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Developmental Mechanism and Distribution Pattern of Stomatal Clusters in Begonia peltatifolia
TANG Min, HU Yu Xi, LIN Jin Xing, JIN Xiao Bai
J Integr Plant Biol 2002, 44 (4): 384-390.  
Abstract (Browse 9772)  |   Save

The function of stomata in plants is controlling gas exchange and modulating water balance. The distribution pattern of stomata in most vascular plants follows a certain regulation with at least one normal epidermal cell between two stomata. However, some plants restricted in several genera of vascular plants have stomatal clusters in which more than one stoma is adjacently arranged with no epidermal cells among them. The developmental process of stomatal clusters in plants, especially in non mutant (wild type) vascular plants, has rarely been documented, and very few studies concerning the distribution pattern of stomatal clusters on leaf epidermis have been carried out. We reported the developmental mechanism and distribution pattern of stomatal clusters in Begonia peltatifolia Li native to China. The results indicated that the clustered arrangement of meristemoids at the juvenile stage of the leaf development contributed greatly to the pattern of stomatal clusters. Additionally, satellite meristemoids derived from subsidiary cells around the mature stomata also had an impact on the development as well as the pattern of stomatal clusters. Regarding stomatal cluster and singly occurring stoma both as a stomatal unit, we found that the stomatal unitdensity (i.e., number of stomatal unit per area) increased gradually from the middle part to the edge and the apex of the leaf, while stomatal unit size (i.e., number of stomata per stomatal unit) decreased. The possible reason of this pattern was discussed.

盾叶秋海棠叶表皮气孔簇的发育及分布格局

唐敏  胡玉熹  林金星  靳晓白*

(中国科学院植物研究所,北京,100093)

气孔是植物控制气体交换和调节水分散失的门户.大部分高等植物气孔的分布格局是相邻气孔之间被一至多个表皮细胞所间隔.而在有限分布的几个科属的植物种中发现气孔成簇分布的现象,即由2至多个紧密相邻的气孔器组成相对独立的单元,称为气孔簇(stoma tal cluster).以中国原产的盾叶秋海棠(Begonia peltatifolia Li)为研究对象,探讨了叶表皮气孔簇的发育机制及其分布格局.结果表明:气孔发育初期,气孔拟分生组织的成簇(相邻紧密)排列可能是气孔簇形成的主要机制;气孔副卫细胞恢复分裂形成的卫星拟分生组织也对气孔簇的形成起一定的作用.把气孔簇和单个气孔视为一个气孔单元发现,盾叶秋海棠气孔单元密度(单位面积中气孔单元数)和气孔单元大小(气孔单元所包含气孔数)在叶片上呈有规律的分布:前者由叶片中部向叶尖、叶缘逐圈增多,而后者逐圈减少.对这种分布格局的成因进行了讨论.

关键词 盾叶秋海棠 发育 分布格局 气孔簇

*通讯作者 Email: xbjin@gengenp.rug.ac.becn

 

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Contributions of Chinese Botanists to Plant Tissue Culture in the 20th Century
CHU Chih-Ching
J Integr Plant Biol 2002, 44 (9): 1075-1084.  
Abstract (Browse 9446)  |   Save

This paper looks back to the development of plant tissue culture in China in the last century. Since 1934, tissue culture studies in China has kept up with the international development in the fields. Progress has been made by Chinese in nea rly every branches of tissue culture, including in vitro organogenesis, shoot tip culture, anther culture, ovary culture, endosperm culture, protoplast culture as well as mass cell culture. On the basis of reviewing the articles written by Chinese on plant tissue culture, the internationally recognized contributions are specially mentioned. The applications of plant tissue culture to agriculture and industry in China are also introduced.

二十世纪我国植物学家对植物组织培养的贡献
朱至清
(中国科学院植物研究所,北京100093)


摘要: 回顾了上一世纪我国植物组织培养的发展。1934年以来,我国的植物组织培养研究一直与国际发展同步进行。我国学者在离体器官发生、茎尖培养、花药培养、子房培养、胚乳培养、原生质体培养和细胞大量培养等分支领域都取得重要进展。本文在引证我国研究者发表的植物组织培养论文的基础上,着重评述了那些被国际同行公认的研究成果。此外,还介绍了植物组织培养在我国农业和工业上应用的情况。
关键词: 植物组织培养;器官发生;茎尖培养;花药培养;子房培养;胚乳培养;原生质体培养;植物细胞大量培养

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The Distribution of Stomata and Photosynthetic Pathway in Leaves
Lin Zhi-fang, Li Shuang-shun and Lin Gui-zhu
J Integr Plant Biol 1986, 28 (4): null.  
Abstract (Browse 8999)  |   Save
The stoma freguency and distribution on both epidermis of leaves of 65 species of C3 plants, 49 species of C4 plants and 16 species of CAM plants were studied by impres- sion method with colorless nail oil. The results indicated that distribution of stoma on both epidermis of leaves was in relation to the photosynthetic pathway and living type. The stoma ratio of upper/lower of C3 plants was 0.45 (sun herb) and 0.07 (shade herb), no stoma was found on upper epidermis of leaves of ferns, shrubs and trees. Plants with C4 photosynthetic pathway, except a few species, showed a higher stoma ratio of upper/lower 0.64 (Cyperaceae), 0.82 (dicot) and 0.94 (Oramineae). Much less stoma frequency was found in CAM plants than in C3 and C4 plant, but the stoma ratio of upper/lower was equal. In C3 crop plants, the species with shorter growth period and higher yield, such as sunflower, peanut and some leafy vegetables had higher stoma ratio of upper/lower. It is supposed that the stoma ratio of upper/lower might be used as an helpful index for identifing the C4 plants in monocot grass. It was also considered that the photosynthetic rate of amphistomatous leaves of C3 plants with same living type was related to the stoma ratio of upper/lower.
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Plant terpenoids: Biosynthesis and ecological functions
Ai-Xia Cheng, Yong-Gen Lou, Ying-Bo Mao, Shan Lu, Ling-Jian Wang and Xiao-Ya Chen
J Integr Plant Biol 2007, 49 (2): 179-186.  
doi: 10.1111/j.1744-7909.2007.00395.x
Abstract (Browse 7446)  |   Save
Among plant secondary metabolites terpenoids are a structurally most diverse group; they function as phytoalexins in plant direct defense, or as signals in indirect defense responses which involves herbivores and their natural enemies. In recent years, more and more attention has been paid to the investigation of the ecological role of plant terpenoids. The biosynthesis pathways of monoterpenes, sesquiterpenes, and diterpenes include the synthesis of C5 precursor isopentenyl diphosphate (IPP) and its allylic isomer dimethylallyl diphosphate (DMAPP), the synthesis of the immediate diphosphate precursors, and the formation of the diverse terpenoids. Terpene synthases (TPSs) play a key role in volatile terpene synthesis. By expression of the TPS genes, significant achievements have been made on metabolic engineering to increase terpenoid production. This review mainly summarizes the recent research progress in elucidating the ecological role of terpenoids and characterization of the enzymes involved in the terpenoid biosynthesis. Spatial and temporal regulations of terpenoids metabolism are also discussed
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The plant vascular system: Evolution, development and functions
William J. Lucas, Andrew Groover, Raffael Lichtenberger, Kaori Furuta, Shri-Ram Yadav, Ykä Helariutta, Xin-Qiang He, Hiroo Fukuda, Julie Kang, Siobhan M. Brady, John W. Patrick, John Sperry, Akiko Yoshida, Ana-Flor López-Millón, Michael A. Grusak, and Pradeep Kachroo
J Integr Plant Biol 2013, 55 (4): 294-388.  
doi: 10.1111/jipb.12041
Abstract (Browse 7332)  |   Save

The emergence of the tracheophyte-based vascular system of land plants had major impacts on the evolution of terrestrial biology, in general, through its role in facilitating the development of plants with increased stature, photosynthetic output, and ability to colonize a greatly expanded range of environmental habitats. Recently, considerable progress has been made in terms of our understanding of the developmental and physiological programs involved in the formation and function of the plant vascular system. In this review, we first examine the evolutionary events that gave rise to the tracheophytes, followed by analysis of the genetic and hormonal networks that cooperate to orchestrate vascular development in the gymnosperms and angiosperms. The two essential functions performed by the vascular system, namely the delivery of resources (water, essential mineral nutrients, sugars and amino acids) to the various plant organs and provision of mechanical support are next discussed. Here, we focus on critical questions relating to structural and physiological properties controlling the delivery of material through the xylem and phloem. Recent discoveries into the role of the vascular system as an effective long-distance communication system are next assessed in terms of the coordination of developmental, physiological and defense-related processes, at the whole-plant level. A concerted effort has been made to integrate all these new findings into a comprehensive picture of the state-of-the-art in the area of plant vascular biology. Finally, areas important for future research are highlighted in terms of their likely contribution both to basic knowledge and applications to primary industry.

Lucas WJ, Groover A, Lichtenberger R, Furuta K, Yadav SR, Helariutta Y, He XQ, Fukuda H, Kang J, Brady SM, Patrick JW, Sperry J, Yoshida A, L´ opez-Mill´an AF, Grusak MA, Kachroo P (2013) The plant vascular system: Evolution, development and functions. J. Integr. Plant Biol. 55(4), 294–388.

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Rice Research: Past, Present and Future
Hong Ma, Kang Chong and Xing-Wang Deng
J Integr Plant Biol 2007, 49 (6): 729-730.  
doi: 10.1111/j.1744-7909.2007.00515.x
Abstract (Browse 6907)  |   Save
Rice Research: Past, Present and Future Rice (Oryza sativa L.) is a major crop in the world and provides the staple food for over half of the world抯 population. From thousands of years of cultivation and breeding to recent genomics, rice has been the focus of agriculture and plant research. China is the home of both the high-yielding hybrid rice and the largest number of rice consumers. The Chinese government has strongly supported rice breeding and research, with anticipated further enhancement of such support in the near future. In this special issue of JIPB on rice research, a total of twenty-two articles discuss recent advances covering a variety of topics, from domestication and breeding to population genetics, from genomics to proteomics, from hormonal signaling to stress responses, and from evolutionary studies to functional analysis of gene families. Rice domestication, breeding and genetics have laid a great foundation for modern rice research. Sang and Ge discuss the current understanding of rice domestication, including the questions that still remain, and Tang and Shi provide a look at rice domestication from the perspective of population genetics. Jiang et al. report the great progress in rice genetics that has been made in recent years in China, including the molecular identification of genes that are important for key traits, such as male sterility, disease resistance, and tillering. Moreover, Li et al. review the analyses of a number of male sterile and restorer lines and their use in the generation of hybrid rice varieties, which have greatly increased rice production. Also, Cheng et al. describe the accomplishments of breeding super hybrid rice using DNA markers, resulting in greater biomass and yield, and discuss possible future challenges and gains in this technology. In addition, Tan et al. summarize the efforts being made in the development of rice lines by introgression from the wild rice Oryza rufipogon into the cultivated rice O. sativa, with the aim of QTLs (quantitative trait loci) affecting yields. These articles both provide historical overviews and highlight current efforts in rice breeding. Successful rice cultivation is intimately linked with hormonal signaling and appropriate responses to biotic and abiotic stresses, including bacterial and fungal disease, and salt and drought stresses. Fan et al. review the advances in the understanding of signal transduction for the hormone gibberellin (GA), which controls plant height and seed germination; both important traits in agriculture. Specifically, recent molecular analyses have resulted in the identification of a GA receptor as a key regulator of ubiquitin-dependent proteolysis, as well as other mediators of GA signaling as components or targets of the ubiquitination pathway. In addition, Gao et al. present a summary of the current understanding of mechanisms conferring tolerance to abiotic stresses, whereas Xu et al. report molecular and biochemical analyses of members of the Xa3/Xa26 gene family conferring disease resistance to bacterial blight and/or fungal blast diseases in rice. Moreover, Hong et al. describe expression results suggesting that the BWMK1 gene is responsive to both stress and hormone signaling, potentially acting to integrate multiple signals. Kong et al. report the molecular analyses of a newly identified rice receptor-like cytoplasmic protein kinase that is specifically expressed in the pollen. If rice breeding and genetic endeavors have generated genetic materials that paved the way for recent advances in studying specific genes that are important for many developmental and physiological traits, then the sequencing of the rice genome and the subsequent functional genomics and proteomics efforts have yielded great volumes of global molecular and biochemical information on many thousands of genes and proteins. Such information has already greatly benefited rice research and allows researchers to investigate specific processes or pathways with a global perspective of the genome and great comprehensiveness hitherto not possible. This will undoubtedly propel rice to become an ever more popular model organism for plant research. In this issue, several articles showcase the varying approaches investigators have taken to characterize rice genomes and proteome. Tang et al. describe a method to use BAC clones, a resource made available by the rice genome projects, as probes to identify rice chromosomes using fluorescence in situ hybridization. Also, Fan et al. demonstrate the power of a microarray-based method to uncover potentially new genes, using Arabidopsis and rice as examples, again using a functional genomics resource to address the fundamental evolutionary problem of gene origins. Weedy rice is a pest in the USA and Olsen et al. provide a brief overview of an ongoing effort to use evolutionary genomics to determine the origin of the weedy red rice and its relationship to other cultivated and wild varieties. The well-known hybrid rice requires male sterile lines, which are altered in their mitochondrial genomes. Liu et al. present a molecular analysis of fertile and sterile mitochondrial genomes and the identification of regions of structural and expression differences, allowing future functional studies of these regions as potential sterility genes. Furthermore, Chen et al. show a proteomic study of plasma membrane-associated proteins induced by the treatment of chitooligosaccharide elicitors that are relevant to disease responses and the identification of the polyprotein-like protein. The rice genome project indicated that many genes are members of gene families, as is the case in Arabidopsis. The available information on gene families presents both opportunities and challenges. To facilitate functional studies of gene family members, it is important to understand the evolutionary relationships between, and the expression patterns among the members. MADS-box genes play critical roles in plant development. Xu and Kong report phylogenetic analyses of floral MADS-box genes in rice and other grasses and provide evidence for the origin of novel regulatory genes by duplication and divergence. Another family important for plant development is the TCP family, controlling cell division, floral organ symmetry and branch formation. Yao et al. present a genome-wide phylogenetic analysis of the TCP genes in Arabidopsis and rice and describe their expression patterns, providing clues to functional relationships among family members. The WRKY gene family encoding transcription factors contains members that are implicated in stress responses. Ross et al. carried out an extensive study of members of the WRKY family in rice and present their genome-wide results, as well as an overview of their functions in stress and hormonal responses. An area of exciting and rapid progress is the regulation of gene expression by small RNAs, as reviewed by Sunkar and Zhu for rice and other plants. In addition, Sun et al. report an analysis of a family of F-box proteins with Kelch repeats, including phylogeny, genome organization and expression. They showed that while some of the subfamilies remained quite stable during the evolution of flowering plants, one subfamily has greatly expanded in the Brassicaseae since they diverged from poplar. Finally, Rohila and Yang reviewed recent progress in the studies of rice genes encoding mitogen activating protein (MAP) kinases, particularly their functions in mediating stress responses. This selection of articles covers a wide range of topics and is indicative of the rapid advances in many areas of rice research in recent years. Undoubtedly, the future of rice research is very exciting, promising to reveal many more secretes about plant biology to promote agriculture and to ultimately benefit human society.
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The Structure Anomalous Secondary Growth of Stem in Gnetum montanum
Gao Xin-zeng, Chen Yao-tang, Deng Yue-fen and Li Rong-ao
J Integr Plant Biol 1984, 26 (6): null.  
Abstract (Browse 6221)  |   Save
In the stem of Gnetnm montanum Mgr. the general arrangement of various tissues and its pattern of secondary growth are very similar to those of angiosperms. The most conspicuous similarity lies in that the xylem contains vessels and the phloem, sieve elements and “companion ceils”. In climbing species of G. montanum, secondary growth initiates in s normal manner which is followed by the development of new combium at various loci among the parenehyms cells towards the periphery of each bundle. It does not initiate from the phloem parenchyma which is in agreement with the findings of Pearson (1929) and Maheshwari etc. (1961). Gradually these loci become incorporated into a continuous cylinder, producing a normally oriented ring of xylem and phloem separated by broad medullary rays. The growth of the first ring ceases at the commencement of the further formation of the outer, successive rings.
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Advances in the Studies on Water Uptake by Plant Roots
ZHAO Chang-Xing, DENG Xi-Ping, ZHANG Sui-Qi, YE Qing, Ernst STEUDLE, SHAN Lun
J Integr Plant Biol 2004, 46 (5): 505-514.  
Abstract (Browse 5756)  |   Save

In the past decade, our understanding of the mechanisms of water uptake by plant roots at the cell, tissue, and whole-plant levels rapidly progressed due to the introduction of new techniques and concepts. Some aspects of this work were reviewed, mainly including the composite structure of roots and effects of the distribution of roots in the soil. The nature of water flow in plant roots was discussed. A link was provided between root hydraulics and the expression and function of aquaporins. This was related to the regulation of water transport and to the signaling between roots and shoots. The composite transport model of root was mentioned which represents a physical model of water uptake. This is part of a comprehensive analysis of recent findings of studies on water uptake by plant roots and contributes to our current understanding of the basic mechanisms that govern the water uptake by roots.

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Isolation of Rice EPSP Synthase cDNA and Its Sequence Analysis and Copy Number Determination
XU Jun-Wang, WEI Xiao-Li, LI Xu-Gang, CHEN Lei, FENG De-Jiang and ZHU Zhen
J Integr Plant Biol 2002, 44 (2): 188-192.  
Abstract (Browse 5560)  |   Save

In order to isolate the total cDNA of rice (Oryza sativa L.) epsps gene, RT-PCR was carried out with template of rice first strand cDNA and primers designed according to rice EPSP synthase genomic sequence obtained in previous study. A 1 585 bp cDNA fragment was amplified and cloned. The 1 585 bp cDNA contains an open reading frame (ORF) comprising of 1 533 nucleotides (nt) which encodes a 511 residue polypepetides, including 67 amino acids chloroplast transit peptide and 444 amino acids EPSP synthase mature peptide. A comparison between the EPSP synthase of diffe rent sources indicates that the mature peptide shows more than 51% identity except for the fungi EPSP synthase and the transit peptide shows considerably less sequence conservation. The copy number of rice epsps gene is estimated to be one copy per haploid rice genome using southern blot. RT-PCR indicated that rice epsps gene is expressed in rice leaves, endosperms and roots and has the highest expression level in leaves.

水稻EPSP合酶cDNA克隆、序列分析及其拷贝数测定

徐军望  魏晓丽  李旭刚  陈蕾  冯德江  朱祯*

(中国科学院遗传和发育生物学研究所,北京 100101)

摘要:根据本室分离的水稻EPSP合酶基因的基因组序列设计一对引物,利用RT-PCR方法首次从水稻(Oryza sativa L. subsp. indica)叶片的RNA中扩增获得了水稻编码EPSP合酶的全长为1 585 bpcDNA片段,它含有一个完整的开放读码框,编码511个氨基酸,包括444个氨基酸组成的成熟肽序列以及N端的67个氨基酸组成的叶绿体转运肽序列.成熟肽氨基酸序列对比表明,除真菌来源的EPSP合酶变异较大外,其他来源的EPSP合酶同源性较高,均在51%以上.而叶绿体转运肽氨基酸序列同源性较低.Southern杂交表明水稻EPSP合酶基因在水稻基因组中以单拷贝形式存在.RT-PCR分析表明,水稻EPSP合酶基因在根、未成熟种子和叶片中均有转录表达,在叶片中表达量最高.

关键词 水稻EPSP合酶 cDNA序列 序列分析 拷贝数 表达

*通讯作者 Email: zzhu@genetics.ac.cn

 

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Comparative Studies on the Physiology of Lowland and Upland Rice I. On the Water Relation and Drought Resistance of Lowland Rice
Yu Shu-veng, Chen Tsing-tsi and Liu Chung-tei
J Integr Plant Biol 1958, 7 (4): null.  
Abstract (Browse 5399)  |   Save
The purpose of the present investigation was to study the water relation and drought resistance of lowland and upland rice in various soil moisture conditions. The plants of two representative varieties “Lao Lai Ching” (lowland rice) and “Nang Ton Xao” (upland rice) were grown in pots with three different conditions; namely: 1. Flooded state with a water layer of 5 cm depth. 2. Moistened state with soil moisture amounting to 70%–75% of the full water-holding capacity. 3. Moistened state with soil moisture amounting to 45%–50% of the full water-holding capacity. The results obtained lead to the following conclusions: It seems that no intrinsic difference in the water relation exists between lowland and upland rice. Both varieties carry on their normal life activities in flooded condition. With regard to the adaptability to upland condition there are distinct differences between them. Cultivation in the moistened state without flooding leads to a poor yield of grain of both varieties, but the reduction in yield being greater in “Lao Lai Ching”. The yield of upland rice is not so much influenced by soil moisture as that of lowland rice. At droughty condition the growth of the upland rice plants far surpasses that of lowland ones, especially in the case of root-system. In upland condition the total water content of leaves is found to decrease, but the degree of decrease is rather greater in “Lao Lai Ching” than in “Nang Ton Xao”. Thus the water dificit of the former is somewhat larger than that of the later. The change of free water content shows the same tendency as the total water content, except that the difference between two varieties is still more significant. The free/bond water ratio of upland rice is also higher than that of lowland rice. In the case of decrease of soil moisture exomosis of electrolytes from leaves increased. However, upland rice is not so sensible to decrease of soil moisture in moistened state. The increase of exomosis owing to the scanty water supply is not so much in “Nang Ton Xao” as in “Lao Lai Ching”. This difference is more marked when exomosis was carried on at high temperature (50 ℃), which indicates that the heat resistance of upland rice is somewhat higher than that of lowland rice. The data presented here supports the suggestion of Prof. Ting, who believes that lowland and upland rice are two ecotypes produced by the edaphic conditions of lowland or upland in the region of cultivation. The relationship of the plant growth, drought resistance and the physiological indicators of water supply has been discussed.
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Advances in Some Plant Groups in ChinaⅠ.A Retrospect and Prospect of Orchidology in China
CHEN Sing-Chi, LUO Yi-Bo
J Integr Plant Biol 2003, 45 (Suppl.): null.  
Abstract (Browse 5205)  |   Save
China is rich in orchid resources and has a long history of orchid appreciation and cultivation. In Chinese ancient literary and artistic works, one can find orchid names as early as about 10th-6th century B. C., orchid paintings in the Northern Song Dynasty (960-1 127) and orchid monographs in the 13th century. Some recent investigations revealed that the cultivation of cymbidiums in China began in the late Tang Dynasty between 860 and 890 A. D. rather than in Confucious times. The first scientific name assigned to Chinese orchids was by Linnaeus in Species Plantarum (1753). Since then many European botanists paid attention to Chinese orchids. Among them R. A. Rolfe, R. Schlechter and recently G. Seidenfaden and P. Cribb are particularly praiseworthy. Their works are considered to be indispensable references until today. In China, H. H. Hu was the first botanist to make a special study on Chinese orchids in 1925, closely followed by S. S. Chien, C. L. Tso, T. Tang and F. T. Wang in the 1930s. After that T. Tang and F. T. Wang continued to study the orchids of China and neighboring areas for decades of years and published many valuable works. They laid a solid foundation for an understanding of the orchid flora of China. At the beginning, the research work was concentrated on the collection, identification and classification of orchids, and then the compilation of the Orchid Flora of China (Flora Reipublicae Popularis Sinicae: Orchidaceae). As a result, a large number of orchid specimens were collected, and nearly ten thousands of colored photographs were taken, and on this ground many books and articles have been published, including three volumes of the Flora Reipublicae Popularis Sinicae (vol. 17-19). Floristic and phytogeographical studies on orchids were made in some areas or mountain chains, such as Sichuan, Xizang (Tibet), Taiwan, Xishuangbanna of southern Yunnan and the Hengduan Mountains. The main achievements include: marking the northern and western limits of lithophytic orchids in China, which almost correspond to those of subtropics; proposing a line, called Kaiyong-Line, separating the Sino-Himalaya and Sino-Japanese Subkingdoms in Sichuan Province; putting forward a suggestion to treat Taiwan as a subdivision of the Malay Subregion of Paleotropical Region floristically; and making a proposal that the proportion of the epiphytic orchid genera amounting to 50% of the total orchid genera might be considered as a symbol of tropical flora. Working on micromorphology of orchids began in the eighties of the last century in China. Nearly 150 species belonging to 40 genera of orchids have been studied cytologically, palynologically, anatomically, embryologically and physiologically. Most of them are natives of China, such as the species of Dendrobium, Cymbidium, Bletilla, Vanda, Pleione, Cypripedium. Hemipilia, Neottianthe, Gastrodia, Anoectochilus, Phaius and Paphiopedilum. Only a few are introduced taxa or hybrids, mostly in Vanilla, Phalaenopsis, Epidendrum, Cattleya and Oncidium. Orchids relate to a thriving industy. Great attention has long been paid to their micropropagation in China. The experiments in tissue culture, seed germination and seedling culture have succeeded in many genera, such as Cymbidium, Dendrobium, Anoectochilus, Spathoglottis, Doritis, Vanilla, Phalaenopsis, Cattleya and Epidendrum. Artificial hybrids have been bred in Paphiopedilum, Cymbidium, Dendrobium, Phalaenopsis, Phaius and Calanthe. However, a lot of work was done more scientifically than commercially. Only few hybrids have been found in markets. Cymbidiums are among the best of the favorable ornamental orchids in China. In recent years, several hundreds of Cymbidium plantations, as well as much more private yards, have been set up in China mainland, Taiwan and Hong Kong. Decades of popular books on their cultivars have been published, and the orchid exhibitions are held frequently. Although it is beneficial to millions of orchid amateurs, many species of Cymbidium have become seriously endangered or quite rare. As a kind of folk drugs, Gastrodia elata Bl. was used in China some 2 000 years ago, and still occupies an important place in traditional Chinense medicine today. A comprehensive study has been made on this species. Its micropropagation, cultivation and production have succeeded by adding Mycena osmundicola Lange to its seeds, and then Armillariella mellea (Vahl. ex Franch.) Karst. to its protocorms. In China, orchid microrrhizae have been studied of 44 species belonging to 20 genera, such as Cymbidium, Dendrobium, Bulbophyllum, Liparis, Vanda, Vandopsis, Eria, etc. Altogether 13 genera of fungi have been isolated and identified: Ceratorhiza, Epulorhiza, Moniliopsis, Fusarium, Mycena, Cylindrocarpon, Myceliophthoreae, Cephalosporium, Ceratorhiza, Chromosporium, Rhizoctomia, Gloiocladium and Pestalotina. The symbiotic germination and growth between Gastrodia elata and fungi, especially Mycena and Armillariella, have been closely investigated. Chinese botanists began to work on pollination biology of orchids in the 1990s. Some species of Satysium, Hemipilia, Changnienia, Holcoglossum, Cypripedium and Paphiopedilum have been observed, but only two articles have been publis hed on Hemipilia and Changnienia until recently. Hemipilia flabellate Bur. et Franch. was reported relying on deception to attract visitors. Its flowers are similar to those of Ajuga forrestii Diels (Labiatae). The latter appears to be the main or exclusive subsidiary nectar source for the pollinators. Recently great attention has been paid to orchid conservation in China. General policies have been carried out and some efforts have been made to improve the situation. This is in fact a complicated problem, not only depending on education and economic development, but also to a large extent on the biological characters of the orchids themselves. It needs a comprehensive study of ecology, population biology, pollination biology, breeding biology and other biological branches. In recent years, studies have been made on some species of Changnienia, Tangtsinia, Paphiopedilum and Cypripedium. However, we still face having little or limited knowledge of the plants themselves, particularly the biological factors that cause orchids to be endangered. China has made good progress in orchidology since the twenties of the last century. Looking forward to the future, the main target is to make scientifically further and comprehensive studies on those taxa endemic or subendemic to China or distributed mainly in China, and commercially applied studies on those of ornamental or medicinal significance. Among the most important genera, for example, are Paphiopedilum, Dendrobium, Cypripedium, Cymbidium, Pleione, Holcoglossum, Anoectochilus and some taxa in subtribe Orchidinae and those introduced from abroad. Of course, more international collaboration will be needed in the future.
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Understanding Abiotic Stress Tolerance Mechanisms: Recent Studies on Stress Response in Rice
Ji-Ping Gao, Dai-Yin Chao and Hong-Xuan Lin
J Integr Plant Biol 2007, 49 (6): 742-750.  
doi: 10.1111/j.1744-7909.2007.00495.x
Abstract (Browse 5022)  |   Save

Abiotic stress is the main factor negatively affecting crop growth and productivity worldwide. The advances in physiology, genetics, and molecular biology have greatly improved our understanding of plant responses to stresses. Rice plants are sensitive to various abiotic stresses. In this short review, we present recent progresses in adaptation of rice to salinity, water deficit and submergence. Many studies show that salt tolerance is tightly associated with the ability to maintain ion homeostasis under salinity. Na+ transporter SKC1 unloads Na+ from xylem, plasma membrane Na+/H+ antiporter SOS1 excludes sodium out of cytosol and tonoplast Na+/H+ antiporter NHX1 sequesters Na+ into the vacuole. Silicon deposition in exodermis and endodermis of rice root reduces sodium transport through the apoplastic pathway. A number of transcription factors regulate stress-inducible gene expression that leads to initiating stress responses and establishing plant stress tolerance. Overexpression of some transcription factors, including DREB/CBF and NAC, enhances salt, drought, and cold tolerance in rice. A variant of one of ERF family genes, Sub1A-1, confers immersion tolerance to lowland rice. These findings and their exploitation will hold promise for engineering breeding to protect crop plants from certain abiotic stresses.

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Mechanisms of the Anticancer Action of Ganoderma lucidum (Leyss. Ex Fr.) Karst.: A New Understanding
Gao-Qiang LIU and Ke-Chang ZHANG
J Integr Plant Biol 2005, 47 (2): null.  
DOI: 10.1111/j.1744-7909.2005.00037.x
Abstract (Browse 4992)  |   Save
Ganoderma lucidum (Leyss. ex Fr.) Karst., a medicinal fungus called “Lingzhi” in China, has been used in traditional Chinese medicine in China for the prevention and treatment of various types of diseases, such as cancer, hepatopathy, arthritis, hypertension, neurasthenia, and chronic hepatitis. It is clear that the anticancer activity of G. lucidum is mainly due to polysaccharides and/or triterpenoids of the fungus. However, until now, the mechanism of the anticancer action of G. lucidum has not been well understood and, previously, the activation of the immune response of the host was widely considered to be the only mechanism by which G. lucidum prevented and/or treated cancer. However, recent studies reviewed in the present paper have shown that the potential mechanisms of anticancer action include not only the activation of the immune response of the host, but also the induction of cell differentiation, the induction of Phase II metabolizing enzymes, the inhibition of angiogenesis, and the inhibition of the expression of the urokinase-type plasminogen activator (uPA) and the uPA receptor in cancer cells. To further elucidate the mechanisms of action of G. lucidum, more in vivo tests and randomized controlled clinical trials should be carried out, and the molecular mechanisms should be studied intensively. Additionally, whether the anticancer compounds in G. lucidum act synergistically or independently should be further studied.
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Development of Abnormal Plantlets and Their Normalization During Cotton Tissue Culture
Zhang Bao-hong, Li Xiu-lan, Li Feng-lian and Li Fu-guang
J Integr Plant Biol 1996, 38 (11): null.  
Abstract (Browse 4957)  |   Save
There was a high frequency in the occurrence of abnormal plantlets during cotton (Gossypium hirsutum L. ) tissue culture. Their patterns, ways of development and effected factors, and the technique of their normalization were studied. Based on their morphologic characters, they could be classified into ten kinds, viz. growing point-abnormal plantlets, cotyledon-, hypocotyl-, united-, fasciculated-, single-leaf-, albino-, vitreous-, browning-, and callus forming plantlets. The growing point- and the cotyledon-abnormal plantlets, which were more commonly seen and were affected by multiple factors, are mainly influenced by the kind of explants, the medium composition, the method and time of culture. The abnormal plantlets could either developed from abnormal embryos or transformed from normal plantlets. Under suitable culture condition reversion of abnormality to normal was possible, however such normalization varied with different genotypes and media. The authors point out the interaction of external regulation and intrinsic developmental mechanism as the main factor causing the accurrence of abnormal plantlet and also discuss the technical procedures of reducing the occurrence frequency of such abnormal plantlets which greatly impact cotton tissue culture.
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Structure of Embryo Sac Before and After Fertilization and Distribution of Transfer Cells in Ovules of Green Gram
Wang Chun-gang and Xi Xiang-yuan
J Integr Plant Biol 1992, 34 (7): null.  
Abstract (Browse 4868)  |   Save
The structure of embryo sac before and after fertilization, embryo and endosperm development and transfer cell distribution in Phaseolus radiatus were investigated using light and transmission electron microscopy. The synergids with distinct filiform apparatus have a chalazal vacuole, numerous mitochondria and ribosomes. A cell wall exists only around the micropylar half of the synergids. The egg cell has a chalazally located nucleus, a large micropylar vacuole and several small vacuoles. Mitochondria and plasrids with starch grains are abundant. No cell wall is present at its chalazal end. There are no plasma membranes between the egg and central cell in several places. The zygote has a complete cell wall, abundant mitochondria and plastids containing starch grains. Both degenerated and persistent synergids migh.t serve as a nutrient supplement to proembryo. The wall ingrowths occur in the central cell, basal cell, inner integumentary cells, suspensor cells and endosperm cells. These transfer cells may contribute to embryo nutrition at different developmental stages of embryo.
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Vegetation and Climate Variations at Taibai, Qinling Mountains in Central China for the Last 3 500 cal BP
Xiao-Qiang LI, John DODSON, Jie ZHOU, Su-Min WANG,Qian-Li SUN
J Integr Plant Biol 2005, 47 (8): 905-916.  
doi: 10.1111/j.1744-7909.2005.00133.x
Abstract (Browse 4862)  |   Save
Pollen records of two swamp sections, located at Taibai Mountain, the highest peak in the Qinling Mountains of central China, show variations of vegetation and climate for the last 3 500 cal BP. The pollen assemblage at the Foyechi and Sanqingchi sections and the surface soil pollen allowed us to reconstruct a high-altitude vegetation history at Taibai Mountain for the first time. The data indicated that there was a cold-dry climate interval between 3 500 and 3 080 cal BP and a relatively warm and wet period compared with the present from 3 080 to 1 860 cal BP. The warmest period in the late Holocene on Taibai Mountain was from 1 430 to 730 cal BP, with an approximate 2 °C increase in mean annual temperature compared with today. There was a relatively cool-dry climate interval from 730 to 310 cal BP. After 310 cal BP, a mountain tundra vegetation developed again and the position of the modern tree line was established.
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A Study of Safe Moisture Content of Rice Grains during Storage
Chao Tung-fang and Wang Ming-chi
J Integr Plant Biol 1955, 4 (4): null.  
Abstract (Browse 4772)  |   Save
Four quantifies of a late variety of unglutinous flee, Lao-lai-ching, harvested in the current year (1954) were sunned/or different periods of time to have their respective moisture contents reduced to 13.6%, 15.2%, 17.2%and 19.6%. From each of them six equal portions were taken and placed in six replicated 1000-ml bottles, three aerated and three sealed up. These 24 bottles were equally grouped and stored in three incubators at different temperatures, 15℃, 25℃ and 35℃, and they were arranged in such a way that one pair of bottles (one aerated and one sealed up)from each of the above-mentioned four groups with different percentages of moisture content were put in one incubator. Three months later, determinations of the percentage of germination and fatty acid, the vitamin B1 content, the number and kinds of molds and the grade of the dehulled rice turned out therefrom were made. From the results thus obtained we find as follows: 1. From the standpoint of the maintenance of the germination percentage, the appropriate moisture content of rice grains during storage should be less than 13% at 35℃, not over 15% at 25℃ and no more than 17% at 15℃. 2. Laboratory storage of rice with different moisture contents for three months under both sealed-up and aerated conditions at different temperatures showed differences in fatty acid content from the original samples. The factors favouring the increase in fatty acid content are: (1) high temperature and (2) high moisture content. 3. There are certain relations between the fatty acid content and the grade of the dehulled rice. Generally, the higher the fatty acid content is, the lower will be the grade of rice. As regards the vitamin B1 content, however, only very slight changes were noticed. 4. The number of mold spores per gram of rice grains stored under the aerated condition was notoably different from that of mold spores per gram of rice grains stored under the sealed-up condition. Further analysis showed more tremendous differences at different temperatures in the aerated bottles than in the sealed-up bottles. 5. The molds isolated most often from the rice grains were Aspergillus sp. Alternaria tenuis, Brachysporium sp., Cladosporium herbarum, Cephalothecium roseum, Curvularia lunata,Fusarium spp., Helminthosporium oryzae, Helicoceras sp., Nigrospora oryzae Mucor spp., Penicillium spp., Phoma sp., and Trichoconis Padwickii. At 35 ℃, isolations made from rice grains under the aerated condition gave birth chiefiy to Aspergillus spp., Mucor spp., and Penicillium spp., and those from the sealed-up ones brought forth Penicillium spp., and Tricoconis Padwickii. At 25 ℃ and 15℃, all the 14 genera of molds listed above were isolated from individual rice kernels in both the aerated and dealed-up bottles with the agar-plate method. 6. It is a general .experience that the newly-harvested Lao-lai-ching offers superior white unglutinous rice when dehulled. If one intends to maintain this high grade for three months or longer, he has to keep the moisture content of rice grains at less than 14% at 35℃, not over 14% at 25℃ and around 15% at 15℃. This paper discusses certain complex interrelationships amoung the percentage of germination, the fatty acid content., the vitamin B1 content, the number and kinds of molds, and the grade of the dehulled rice. It points out the necessity for further physiological and biochemical investigations in connection with grain storage.
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Metabolic Engineering of Tropane Alkaloid Biosynthesis in Plants
Lei ZHANG, Guo-Yin KAI, Bei-Bei LU, Han-Ming ZHANG, Ke-Xuan TANG, Ji-Hong JIANG and Wan-Sheng CHEN
J Integr Plant Biol 2005, 47 (2): 136-143.  
doi: 10.1111/j.1744-7909.2005.00024.x
Abstract (Browse 4765)  |   Save
Over the past decade, the evolving commercial importance of so-called plant secondary metabolites has resulted in a great interest in secondary metabolism and, particularly, in the possibilities to enhance the yield of fine metabolites by means of genetic engineering. Plant alkaloids, which constitute one of the largest groups of natural products, provide many pharmacologically active compounds. Several genes in the tropane alkaloids biosynthesis pathways have been cloned, making the metabolic engineering of these alkaloids possible. The content of the target chemical scopolamine could be significantly increased by various approaches, such as introducing genes encoding the key biosynthetic enzymes or genes encoding regulatory proteins to overcome the specific rate-limiting steps. In addition, antisense genes have been used to block competitive pathways. These investigations have opened up new, promising perspectives for increased production in plants or plant cell culture. Recent achievements have been made in the metabolic engineering of plant tropane alkaloids and some new powerful strategies are reviewed in the present paper.
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Characterization of the Rice Floral Organ Number Mutant fon3
Li JIANG, Qian QIAN, Long MAO, Qing-Yuan ZHOU and Wen-Xue ZHAI
J Integr Plant Biol 2005, 47 (1): 100-106.  
doi: 10.1111/j.1744-7909.2005.00017.x
Abstract (Browse 4758)  |   Save
A spontaneous rice mutant named floral organ number 3 (fon3) had major mutations in floral organ numbers. Genetic analysis indicated that fon3 acted as a single recessive gene. Microscopic observation showed that the number of floral organs in fon3 increased centripetally. For example, the number of pistils was the more frequently increased than organs in the outer whorls. Homeotic conversion of lodicules and glumes into palea/lemma-like organs was observed in some flowers. Scanning electron microscopy observation showed that the size of flower meristems was maintained the same or similar until the lemma primordium started to differentiate, at which time the floral meristem became enlarged, suggesting abnormal development of the inner whorls of rice florets. The relationship of fon3 with other similar rice mutants is discussed.
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Recent Progress in Arabidopsis Research in China: A Preface
Zhi-Hong Xu
J Integr Plant Biol 2006, 48 (1): 1-4.  
Abstract (Browse 4735)  |   Save
In 2002, a workshop on Arabidopsis research in China was held in Shanghai, when a small group of Chinese plant scientists was working on this model species. Since then, we have witnessed the rapid growth of Arabidopsis research in China. This special issue of Journal of Integrative Plant Biology is dedicated exclusively to the Fourth Workshop on Arabidopsis Research in China, scheduled on November 30, 2005, in Beijing. In addition to reports collected in this special issue, the Chinese Arabidopsis community has been able to make significant contributions to many research fields. Here, I briefly summarize recent advances in Arabidopsis research in China. Fatty acid homeostasis has long been thought as an important mechanism to regulate cellular signaling in a variety of organisms, but little is known about the direct physiological consequence of this regulation in higher plants. The characterization of the MOD1 gene demonstrated that de novo fatty acid synthesis is fundamental for plant growth and development by regulating various cellular signaling activities, such as apoptosis. The MOD1 gene encodes an enoyl-acyl carrier protein reductase, which is a subunit of the fatty acid synthase complex. The mod1 mutation causes premature cell death and a variety of developmental defects (Mou et al. 2000). Analogously, a loss-of-function mutation in the PEAMT gene, which encodes a rate-limiting enzyme involved in an early step of membrane phospholipid phosphatidylcholine biosynthesis, causes a pleiotropic phenotype and temperature-sensitive male sterility, as well as hypersensitivity to salinity, highlighting the importance of this class of complex lipids in plant cellular signaling (Mou et al. 2002). In efforts to elucidate the molecular mechanism of leaf development, ERECTA was defined to act in the ASYMMETRIC LEAVES1 (AS1)-AS2 pathway, in which AS1 and AS2 may form a complex (Xu et al. 2003). Surprisingly, AS1and AS2 act synergistically with the RNA-dependent RNA polymerase RDR6 to repress BREVIPEDICELLUS (BP) and MicroRNA165/166 (miRNA165/166), which likely target class III HD-ZIP proteins (Li et al. 2005). Therefore, this highly interactive network plays a key role in specifying leaf adaxial identity. A systematic characterization of BP function is also reported in this issue (Wang et al. 2006). The WUSCHEL (WUS) gene is well known as a key component of shoot meristem development. A gain-of-function mutation in WUS causes the formation of ectopic floral buds along inflorescence stems, thus revealing a novel function of the homeodomain protein in floral meristem development (Xu et al. 2005). During reproductive development, the SLOW WALKER1 (SWA1) gene, encoding a WD40 protein involved in rRNA biogenesis, was found to be essential for the cell cycle progression during gametogenesis. The swa1 mutation causes asynchronous development of megagametophytes, leading to the developmental arrest of embryo sacs at various stages. In addition, SWA1 also appears to play a role in root development (Shi et al. 2005). Genome-wide identification and characterization of Arabidopsis S-locus F-box-like (AtSFL) genes have shed light on the molecular functions of these Antirrhinum orthologs in plant growth and development. It is interesting to note that mutations in several AtSFL genes cause defective embryogenesis or female gametogenesis (Wang et al. 2004). De novo synthesis of the phytohormone auxin has been thought to be primarily through a tryptophan (Trp)-dependent pathway. However, a Trp-independent pathway was identified and characterized, in which indole-3-glycerol phosphate appears to act as a branch-point compound in this novel pathway (Ouyang et al. 2000). More recently, an indole-3-acetic acid (IAA) carboxyl methyltransferase (IAMT1) was shown to convert IAA into methyl-IAA ester, thereby regulating auxin homeostasis. A gain-of-function mutation in IAMT1 causes dramatic hyponastic leaf phenotypes, consistent with a decreased expression level of several TCP genes that are known to regulate leaf curvature (Qin et al. 2005). In auxin signaling, the BUD1/MAPKK7 gene was characterized as a negative regulator of polar auxin transport and the gain-of-function mutant bud1 displays pleiotropic phenotype characteristics of the auxin-deficient syndrome (Dai et al. 2006). This study provides the first line of evidence showing the involvement of the conserved mitogen-activated protein kinase signaling cascade in the control of auxin signal transduction. In parallel with these findings, Auxin Response Factor (ARF) 10 and ARF16, two key regulators controlling root cap development, were found to be targeted by miRNA160. Overexpression of miRNA160 displays a phenotype similar to that of an arf10/arf16 double mutant, characteristics of uncontrolled cell divisions and blocked cell differentiation in the root distal region, thereby causing the formation of a tumor-like root apex and the loss of gravity sensing. Interestingly, the repression of ARF10 and ARF16 by miRNA160 appears to be auxin independent (Wang et al. 2005). Previous genetic and molecular studies indicate that auxin-mediated lateral root development requires multiple components, such as the transcription factor NAC1 and an F-box protein TIR1. However, two recent studies suggest that the regulatory network is more complicated than expected. Overexpression of the novel transcription factor gene NAC2 promotes the formation of lateral roots, a phenotype similar to that of NAC1. In contrast with NAC1, NAC2 is regulated by auxin, ethylene, and abscisic acid (ABA), as well as by salt stress. Moreover, the salt regulation of NAC2 requires functional auxin and ethylene pathways, although its physiological significance remains unclear. It was proposed that NAC2 functions in regulating lateral root development by the integration of environmental and endogenous stimuli (He et al. 2005). A second new player in lateral root development is the auxin-inducible gene CEGENDUO (CEG), which encodes a novel F-box protein. The formation of lateral roots is promoted in a ceg-knockout mutant, but inhibited in transgenic plants overexpressing CEG. Therefore, CEG appears to negatively regulate lateral root formation in an auxin-dependent manner (Dong et al. 2006). Although polar transport of auxin has been well documented, very little is known about the transport of other plant hormones. Equilibrative nucleoside transporters (ENTs) are a class of evolutionarily conserved proteins that are involved in the transport of nucleosides in all eukaryotic organisms. Molecular and biochemical studies identified eight ENT genes in the Arabidopsis genome (Li et al. 2003). A recent study suggests that AtENT8/SOI33 and AtENT3 appear to function as transporters of cytokinin, a phytohormone derived from nucleosides (Sun et al. 2005). Equally exciting findings were also made in studies on brassinosteroid signaling. Brassinosteroids have long been appreciated as key regulators of cell elongation. However, brassinosteroids were also found to be important for cell division in a CycD3-dependent manner (Hu et al. 2000). Moreover, brassinosteroids were found not only to alter the expression of PIN genes, which encode auxin efflux carrier proteins, but also to promote functional localization of PIN2 modulated by ROP. Consistent with these observations, brassinosteroids were manifested to promote plant tropisms by modulating polar auxin transport (Li et al. 2005). Remarkably, a novel membrane steroid-binding protein (MSBP1) was found to be capable of binding various steroids, including 24-epi-brassinolide, in an in vitro assay. Transgenic studies suggest that the MSBP1 expression level is well correlated with the steroid-binding capacity, reduced cell elongation, and shorter hypocotyls, as well as sensitivities to exogenous progesterone and 24-epi-brassinolide. Thus, the light-responsive MSBP1 acts as a negative regulator of steroid signaling by controlling cell elongation and hypocotyl elongation (Yang et al. 2005). This study identifies the first functional steroid-binding protein in higher plants. Cryptochrome1 (CRY1) is a blue light receptor that mediates light signaling, presumably through its C-terminal domain. In an effort to characterize the N-terminal domain of CRY1 functionally, Sang et al. (2005) revealed that this domain was essential for dimerization of the photoreceptor, which, in turn, was required for light activation of the C-terminal domain. Intriguingly, CRY1 and CRY2 were also shown to be involved in the control of stomatal opening, which is physiologically connected to both water evaporation and photosynthesis in plants (Mao et al. 2005). Calcium has been implied in many aspects of cellular signaling in plants. The PPF1 gene, encoding a putative calcium ion carrier, is functional in both plant and human cells. The PPF1 gene appears to play an important role in multiple signaling pathways, particularly in the control of the flowering time. Indeed, whereas overexpression of PPF1 caused a late flowering phenotype, suppression of PPF1 expression resulted in an opposite phenotype (Wang et al. 2003). On the other hand, biochemical and physiological studies have demonstrated the presence of the Ca2+-permeable channels in the plasma membranes of pollens and pollen tubes. Moreover, dynamic actin microfilaments have been shown to control Ca2+ channel activity, which may, consequently, regulate cytoplasmic Ca2+, thus playing crucial roles in the regulation of pollen germination and tube growth (Wang et al. 2004). Cytosolic free Ca2+ in the regulation of stomatal movement has also been documented. Extracellular calmodulin was found to induce an increased level of H2O2 and cytosolic free Ca2+, leading to a reduction in stomatal aperture. Genetic analysis indicates that the extracellular calmodulin-modulated intracellular signaling is involved in the activation of a heterotrimeric G-protein (Chen et al. 2004). Epigenetic control of plant growth and development has been emerging as a main theme in recent years. In addition to the functional characterization of several microRNAs highlighted above, two recent studies have provided important insights into the epigenetic regulation in Arabidopsis. In root development, the identity of epidermal cells is determined by a small group patterning genes. Hyperacetylation of the core histones H3 and H4, manipulated by trichostatin A (TSA; an inhibitor of histone deacetylase) treatment or a mutation in a histone deacetylase gene, altered the expression of these patterning genes, thereby causing misspecified identity of certain epidermal cells (Xu et al. 2005). In a genetic screen for suppressors of ros1, which causes transcriptional silencing of a transgene and a homologous endogenous gene (Gong et al. 2002), two allelic mutants, namely ror1-1 and ror1-2, were identified. The ROR1 gene, encoding a protein similar to DNA replication protein A2, is involved in epigenetic gene silencing, likely in a DNA methylation-independent manner (Xia et al. 2006). In efforts in functional genomics programs, an ORFeome collection, representing 1 282 Arabidopsis transcription factor (TF) genes, was generated. Using a 70-mer-oligo array, the expression profiles of 66 MADS-box transcription factor genes and the relative distribution of expression abundance of 858 transcription factors were analyzed (Gong et al. 2004). A database of Arabidopsis transcription factors (DATF), representing 1 826 TF genes from 56 families, has been established at Peking University (Guo et al. 2005; see also http://datf.cbi.pku.edu.cn). Among these TF genes, two families, AP2/EREBP (Feng et al. 2005) and MYB (Chen et al. 2005), have been analyzed systematically and intensively. In addition, more than 125 000 T-DNA activation tagging lines were generated. These lines were generated using a 35S enhancer vector (PKU lines; 85 000 lines) and a chemical-inducible vector (IGDB lines; 40 000 lines), of which approximate 30 000 lines have been released to academic users (Qin et al. 2003; Zhang et al. 2005). Whereas these tremendous efforts and impressive achievements have been made during the past few years at a remarkably encouraging pace, the Arabidopsis research community keeps growing and becoming stronger in China. Therefore, we have every reason to believe in a great future for this young and energetic community. Acknowledgements I am grateful to Drs Jia-Yang Li, Yong-Biao Xue, Kang Chong, Hong-Wei Xue, Wei-Cai Yang and Jian-Ru Zuo for critically reading the manuscript. I would apologize to colleagues whose work is not cited in this minireview owing to space limitations.(Author for correspondence.College of Life Sciences, Peking University, Beijing 100871, China.Tel: +86 (0)10 6275 1200; Fax: +86 (0)10 6275 1207; E-mail: xuzh@pku.edu.cn)
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The WRKY Gene Family in Rice (Oryza sativa)
Christian A. Ross, Yue Liu and Qingxi J. Shen
J Integr Plant Biol 2007, 49 (6): 827-842.  
doi: 10.1111/j.1744-7909.2007.00504.x
Abstract (Browse 4702)  |   Save

WRKY genes encode transcription factors that are involved in the regulation of various biological processes. These zinc-finger proteins, especially those members mediating stress responses, are uniquely expanded in plants. To facilitate the study of the evolutionary history and functions of this supergene family, we performed an exhaustive search for WRKY genes using HMMER and a Hidden Markov Model that was specifically trained for rice. This work resulted in a comprehensive list of WRKY gene models in Oryza sativa L. ssp. indica and L. ssp. japonica. Mapping of these genes to individual chromosomes facilitated elimination of the redundant, leading to the identification of 98 WRKY genes in japonica and 102 in indica rice. These genes were further categorized according to the number and structure of their zinc-finger domains. Based on a phylogenetic tree of the conserved WRKY domains and the graphic display of WRKY loci on corresponding indica and japonica chromosomes, we identified possible WRKY gene duplications within, and losses between the two closely related rice subspecies. Also reviewed are the roles of WRKY genes in disease resistance and responses to salicylic acid and jasmonic acid, seed development and germination mediated by gibberellins, other developmental processes including senescence, and responses to abiotic stresses and abscisic acid in rice and other plants. The signaling pathways mediating WRKY gene expression are also discussed.

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A Note from the Executive Editor
Chun-Ming Liu
J Integr Plant Biol 2007, 49 (1): 1-2.  
doi: 10.1111/j.1744-7909.2006.00423.x
Abstract (Browse 4629)  |   Save

When Professor Xing-Guo Han, one of the Chief Editors of Journal of Integrative Plant Biology (JIPB) and President of the Botanical Society of China, and Professor Ke-Ping Ma, the Director General of the Institute of Botany, the Chinese Academy of Sciences (CAS), asked me if I would like to be the Executive Editor for JIPB, it really took me a few days to think about it. The major reason for me to be so reluctant to take such a position was that I felt I really did not have enough time to manage a journal promptly, by hiding away from my daily business. At the moment, I run my own laboratory, and take care of the management job for the Center of Signal Transduction & Metabolomics. In addition, I also did not have any experience in editorial business. However, they managed to convince me to take the challenge, by giving me their full support. Anyway, I agreed in the end. I will do my best to assist the Editors to bring up the quality of the journal. Regardless of whether or not I reach my goal, it will be a valuable experience for me. JIPB was established in 1952, for the first 52 years published under the name of Acta Botanica Sinica, and changed to its current name in 2005. It was a quarterly magazine first, and then published bimonthly from 1981, and monthly since 1989. During its 54-year history, the Journal has always been the leading plant science journal in China. It has also witnessed the dark period of the country, when the Journal was stopped for a period of 7 years (between mid-1966 and mid-1973) due to the cultural revolution? In January 2005, the Journal formally entered into a co-publishing partnership with Blackwell Publishing, and now it appears online in Blackwell Synergy, which is available to over 3 000 universities worldwide. Over the last few weeks, I have spoken to many plant scientists, and Dr. Jin-Zhong Cui, the managing editor, to get their advice. The general idea is that to improve the quality of the journal, we need to rethink the strategy. After these discussions we came to the following conclusions: 1) The general scope: with the aim to bring the Journal to a higher standard, we need to have a clear scope for the Journal. We will publish invited reviews to bring our readers to state-of-the-art scientific developments, and research articles with broad interests to plant scientists, with particular focus on those articles that could answer basic biological questions by using reproducible experimental and statistical analyses. We will not consider those purely descriptive observations or confirmation works. The way of describing and discussing the results must be appropriate for a wide audience of plant biologists. 2) The reviewing process: one major change we made in terms of the peer-review process was to establish a board of enthusiastic scientists (see the list below) to be Area Responsible Editors (ARE). These Editors take full responsibility of an area of his/her expertise, and facilitate the peer-reviewing process and decision-making thereafter. To speed up the publication cycle, we are making several changes to the review process: a) we will use Stanford University Library抯 HighWire Press software (the same publication platform used by Plant Cell and Plant Physiology) for handling the manuscript processing; b) at the time when the corresponding author submits the article, he/she must identify the proper ARE; c) we will eliminate the page restriction for each issue, to allow a fast publication even when too many or too few papers have been accepted; d) we will have a PubExp column for rapid publication of papers with exceptional discoveries whereby the manuscript is submitted directly to the Executive Editor; e) we will hire two or three new editorial staff to support the communication, editing and typesetting. 3) New protocols: we will publish methodology papers to describe procedures that could be used reproducibly in other laboratories for studies in plant sciences. Of course, the most important thing to make a good journal is to get the support from you, the readers, the authors, the reviewers and the editors. I hope we can work together with you to allow JIPB to be an internationally recognized journal. To reach this goal, we need good manuscripts, critical reviewers, speedy publication and the best services. If you have suggestions and comments, please do not hesitate to contact me. Sincerely, Chun-Ming Liu, PhD The ARE members 1) Ecology Prof. Jianguo (Jingle) Wu (landscape & urban ecology) Arizona State University, USA Prof. Jianxin Sun (ecosystems & modeling) Institute of Botany, CAS, China Prof. Jiquan Chen (forest ecology, conservation biology) The University of Toledo, USA Prof. Weixin Cheng (ecosystem) University of California, USA 2) Stress & Phytochemistry Prof. Wei-Hua Wu (membrane channel) China Agricultural University, China Prof. Zhi-Zhong Gong (abiotic stress) China Agricultural University, Beijing Prof. Daoxin Xie (viral and bacterium diseases) Tsinghua University, China Prof. Ninghua Tan (phytochemistry & functional products) Kunming Institute of Botany, CAS, China Prof. Xiao-Quan Qi (metabolites/fungal diseases) Institute of Botany, CAS, China 3) Omics & Epigenetics Prof. Jun Yu (transcriptome, bioinformatics) Beijing Institute of Genomics, CAS, China Prof. Dabing Zhang (rice functional genomics) Shanghai Jiao Tong University, China Prof. Bin Han (genomics; genome evolution) National Center for Gene Research, CAS, China Prof. Tai Wang (proteomics) Institute of Botany, CAS, China Prof. Xiaofeng Cao (epigenetics) Institute of Genetics & Developmental Biology, CAS, China 4) Development & Photosynthesis Prof. Da Luo (flower development) Institute of Plant Physiology & Ecology, CAS, China Prof. Yuxin Hu (vegetative organ development & architecture) Institute of Botany, CAS, China Prof. Wei-Cai Yang (pollen, embryo sac and embryo development) Institute of Genetics & Developmental Biology, CAS, China Prof. Yong-Biao Xue (fertilization and self-incomparability) Institute of Genetics & Developmental Biology, CAS, China Prof. Jin-Xing Lin (cell biology) Institute of Botany, CAS, China Prof. Cong-Ming Lu (photosynthesis) Institute of Botany, CAS, China 5) Signal Transduction Prof. Hongwei Xue (auxin and BR signaling) Institute of Plant Physiology & Ecology, CAS, China Prof. Xiangdong Fu (GA signaling) Institute of Genetics & Developmental Biology, CAS, China Prof. Hongwei Guo (ethylene signaling) Peking University, China Prof. Jianru Zuo (cytokinin/regeneration/programmed cell death) Institute of Genetics & Developmental Biology, CAS, China Prof. Qi Xie (ABA & protein degradation) Institute of Genetics & Developmental Biology, CAS, China Prof. Chentao Lin (light signal transduction) University of California, Los Angeles, USA 6) Evolution Prof. Yang Zhong (molecular evolution, bioinformatics, statistics) Fudan University, China Prof. Shuang-Quan Huang (reproductive ecology) Wuhan University, China Prof. Song Ge (conservation genetics, molecular systematics) Institute of Botany, CAS, China Prof. Xiao-Quan Wang (biogeography, molecular ecology) Institute of Botany, CAS, China About Professor Chun-Ming Liu Professor Chun-Ming Liu received his BSc degree in 1984 from Shandong Normal University (Jinan), MSc degree in 1987 from Shanghai Institute of Plant Physiology (Shanghai), the Chinese Academy of Sciences, and his PhD degree in 1996 from John Innes Center/University of East Anglia (Norwich, UK). Thereafter, he went to Professor David Meinke抯 laboratory (Stillwater, USA) for his 3-year post-doctoral training. Between 1999 and 2005 he worked as a senior scientist and group leader at Plant Research International (Wageningen, The Netherlands). From the beginning of the year, he became a Professor and Director of the Center for Signal Transduction & Metabolomics, Institute of Botany, the Chinese Academy of Sciences, Beijing. His research is always associated with seed development, in particular in embryogenesis, endosperm development and meristem formation. Selected publications Liu CM, Xu ZH and Chua NH (1993). Auxin polar transport is essential for the establishment of bilateral symmetry during early plant embryogenesis. Plant Cell 5: 621-630. Liu CM, Xu ZH and Chua NH (1993). Proembryo culture: in vitro development of early globular-staged zygotic embryos of Brassica juncea. Plant J 3: 291-300. Liu CM and Meinke DW (1998). The titan mutants of Arabidopsis are disrupted in mitosis and cell cycle control during seed development. Plant J 16: 21-31. Liu CM, McElver J, Tzafrir I, Joosen R, Wittich P, Patton D, van Lammeren AAM and Meinke D (2002). Condensin and cohesin knockouts in Arabidopsis exhibit a titan seed phenotype. Plant J 29: 405-415. Fiers M, Hause G, Boutilier K, Casamitjana-Marinez E, Weijers D, Offringa R, van der Geest L, van Lookeren Campagne M and Liu CM (2004). Mis-expression of the CLV3/ESR-like gene CLE19 in Arabidopsis leads to a consumption of root meristem. Gene 327: 37-49. Xu J, Zhang HY, Xie CH, Xue HW, Dijkhuis P and Liu CM (2005). EMBRYONIC FACTOR 1 encodes an AMP deaminase and is essential for the zygote to embryo transition in Arabidopsis. Plant J 42: 743-756. Fiers M, Golemiec E, Xu J, van der Geest L, Heidstra R, Stiekema W and Liu CM (2005). The 14-amino acid CLV3, CLE19 and CLE40 peptides trigger consumption of the root meristem in Arabidopsis through a CLAVATA2-dependent pathway. Plant Cell 17: 2542-2553. Fiers M, Golemiec E, van der Schors R, van der Geest L, Li KW, Stiekema WJ and Liu CM (2006). The CLV3/ESR motif of CLV3 is functionally independent from the non-conserved flanking sequences. Plant Physiol 141: 1284-1294. Fiers M, Ku KL and Liu CM (2007). CLE peptide ligands and their roles in establishing meristems. Curr Opin Plant Biol (in press).

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Pollen Morphology of Parnassia L. (Parnassiaceae) and Its Systematic Implications
Ding WU, Hong WANG, De-Zhu LI and Stephen BLACKMORE
J Integr Plant Biol 2005, 47 (1): 2-12.  
doi: 10.1111/j.1744-7909.2005.00008.x
Abstract (Browse 4600)  |   Save
The pollen morphology of 28 species of Parnassia L. was investigated with light microscopy and scanning electron microscopy (SEM). The shape of pollen grains in this genus varies from subspheroidal to prolate in equatorial view and is three-lobed circular in the polar view. Pollen grains are usually radially symmetrical, isopolar, tricolporate or syntricolporate, with reticulate sculpture. The pollen characteristics among species are fairly similar to each other. Morphological information regarding the pollen grains shows that Parnassia is a natural genus. Based on exine ornamentation observed under SEM, three types of pollen grains were recognized: (i) type I, with foveolate-reticulate sculpture; (ii) type II, with a finely reticulate sculpture; and (iii) type III, with a coarsely reticulate sculpture. Most sections of this genus have one type of sculpture of pollen morphology, but Sect. Nectarotrilobos has three types of sculpture and Sect. Saxifragastrum has two types of sculpture. All three types of sculpture can be found in Southwest China, with species with the longest (Parnassia delavayi Franch.) and shortest (Parnassia faberi Oliv.) colpi, implying that Southwest China is the center of diversification of the genus.
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Fine Structure of Tapetal Cells and Ubisch Bodies in the Anther of Ophiopogon japonicus
Liu Ning, Wang Fu-xiong (Wang Fu-hsiung) and Chen Zu-keng
J Integr Plant Biol 1992, 34 (1): null.  
Abstract (Browse 4594)  |   Save
The development of the tapetum in Ophiopogon ]aponicus is of secretory type Tapetum develops at their peak during the microspore mother cell stage. There are abundant organelles, consisting of a lot of mitochondria, dictyosomes and plastids, especially endoplasmic reticulum. Pro-Ubisch bodies e. merge as early as at the stage of microspore mother cell. At tetrad stage, a large number of pro-Ubisch bodies accumulate between inner tangential face of the plasmalemma and the cell wall. At the early microspore stage, pro-Ubisch bodies are distributed in the small embayments of the plasmalemma. As the sporopollenin begins to deposit on them, proubisch bodies develop into Ubisch bodies which consist of two types: single and aggregated. Tapetal cells degenerate completely when pollen grains reach maturity.
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Effect of Hillslope Gradient on Vegetation Recovery on Abandoned Land of Shifting Cultivation
Yi Ding, Run-Guo Zang and You-Xu Jiang
J Integr Plant Biol 2006, 48 (6): 642-653.  
doi: 10.1111/j.1744-7909.2006.00262.x
Abstract (Browse 4524)  |   Save
In the present study, we investigated the effect of hillslope gradient on vegetation recovery on abandoned land of shifting cultivation in Hainan Island, south China, by measuring community composition and structure of 25-year-old secondary forest fallows along a hillslope gradient (up-, middle-, and down-slope position). A total of 49 733 free-standing woody plant stems higher than 10 cm and belonging to 170 species, 112 genera, and 57 families was found in the three 1-hm2 investigation plots. Stem density was highest in the down-slope stand and lowest in the up-slope stand. Species richness and the Shannon-Wiener index were both highest in the middle-slope stand, and lower in the down-slope and up-slope stands. The recovery forest fallows on different hillslope positions were all dominated by a few species. The five most abundant species accounted for 70.1%, 58.8%, and 72.9% of total stem densities in stands in the up-, middle-, and down-slope positions, respectively. The five species with the greatest basal areas accounted for 74.5%, 84.3%, and 74.7% of total stem basal area for the up-, middle-, and down-slope positions, respectively. The number of low-density species (stem abundance less than five) increased from the up-slope position downward. Of the nine local common species among three different functional groups, the short-lived pioneer species dominated the up-slope position, but long-lived pioneer species dominated the middle- and down-slope positions. The climax species of primary tropical lowland rain forest was found in the down-slope position. Both the mean diameter at breast height (DBH) and mean height of the trees increased with decreasing hillslope gradient. The stem density and basal area in different size classes were significantly different in stands in different slope positions. Our results indicated that the rate of secondary succession varies, even over small spatial scales caused by the hillslope gradient, in early vegetation recovery.(Author for correspondence.Tel: +86 (0)10 6288 9546; Fax: +86 (0)10 6288 4972; E-mail: zangrung@forestry.ac.cn)
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Intergeneric Somatic Hybridization Between Brassica napus L. and Sinapis alba L.
You-Ping WANG, Karin SONNTAG, Eicke RUDLOFF and Jian-Min CHEN
J Integr Plant Biol 2005, 47 (1): 84-91.  
doi: 10.1111/j.1744-7909.2005.00009.x
Abstract (Browse 4519)  |   Save
Electrically induced protoplast fusion was used to produce somatic hybrids between Brassica napus L. and Sinapis alba L. Seven hybrids were obtained and verified by the simple sequence repeat and cleaved amplified polymorphic sequence analysis of the gene fae1, indicating that the characteristic bands from S. alba were present in the hybrids. The hybridity was also confirmed by chromosome number counting because the hybrids possessed 62 chromosomes, corresponding to the sum of fusion-parent chromosomes. Chromosome pairing at meiosis was predominantly normal, which led to high pollen fertility, ranging from 66% to 77%. All hybrids were grown to full maturity and could be fertilized and set seed after self-pollination or back-crosses with B. napus. The morphology of the hybrids resembled characteristics from both parental species. An analysis of the fatty acid composition in the seeds of F1 plants was conducted and the seeds were found to contain different amounts of erucic acid, ranging from 11.0% to 52.1%.
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Abscisic Acid and Antioxidant Defense in Plant Cells
JIANG Ming-Yi, ZHANG Jian-Hua
J Integr Plant Biol 2004, 46 (1): 1-9.  
Abstract (Browse 4477)  |   Save

Water stress is one of the most important environmental factors that affect plant growth and development, and limit plant production. Plants can respond and adapt to water stress by perceiving the stimulus, generating and transmitting the signals, and initiating various defense mechanisms. The plant hormone abscisic acid (ABA), as a stress signal, plays important roles in the regulation of plant responses to water stress. ABA not only regulates water balance by inducing stomatal closure, but also enhances water stress tolerance by inducing the expression of genes that encode dehydration tolerance proteins. Increasing evidence indicates that ABA-enhanced water stress tolerance is related to the induction of antioxidant defense systems by ABA. In this review, recent advances on the roles of ABA in the induction of the generation of reactive oxygen species (ROS), the expression of antioxidant enzyme genes, and the capacity of antioxidant defense systems are presented. Special attention is given to the cross-talk mecha-nisms between Ca2+ and ROS that originates from NADPH oxidase in the ABA-induced antioxidant defense in plants.

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Dimethyl Sulfoxide Is Feasible for Plant Tubulin Assembly In vitro: A Comprehensive Analysis
Chun-Hua XU, Shan-Jin HUANG,Ming YUAN
J Integr Plant Biol 2005, 47 (4): 457-466.  
doi: 10.1111/j.1744-7909.2005.00086.x
Abstract (Browse 4464)  |   Save
It is much more difficult for tubulin from plant sources to polymerize in vitro than tubulin from animal sources. Taxol, a most widely used reagent in microtubule studies, enhances plant microtubule assembly, but hinders microtubule dynamics. Dimethyl sulfoxide (DMSO), a widely used reagent in animal microtubule studies, is a good candidate for the investigation of plant microtubule assembly in vitro. However, proper investigation is lacking about the effects of DMSO on plant microtubule assembly in vitro. In the present study, DMSO was used to establish optimal conditions for the polymerization of plant tubulin. Tubulin, purified from lily pollen, polymerizes into microtubules at a critical concentration of 1.2 mg/mL in the presence of 10% DMSO. The polymers appear to have a normal microtubule structure, as revealed by electron microscopy. In the presence of 10% DMSO, microtubule polymerization decreases when the pH of the medium is increased from 6.5 to 7.4. Both the polymerization rate and the mass of the polymers increase as temperature increases from 25 to 40 °C. Tubulin polymerizes and depolymerizes along with cycling of temperature, from 37 to 4 °C, or following the addition to or the removal of Ca2+ from the medium. When incubated with nuclei isolated from tobacco BY-2 suspension cells, tubulin assembles onto the nuclear surface in the presence of 10% DMSO. Labeling lily pollen tubulin with 5- (and 6-) carboxytetramethyl-rhodamine succinimidyl ester (NHS-rhodamine) was performed successfully in the presence of 10% DMSO. Labeled tubulin assembles into a radial structure on the surface of BY-2 nuclei. The polymerization of lily pollen tubulin is also enhanced by microtubule-associated proteins from animal sources in the presence of 10% DMSO. All the experimental results indicate that plant tubulin functions normally in the presence of DMSO. Therefore, DMSO is an appropriate reagent for plant tubulin polymerization and investigation of plant microtubules in vitro.
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Cis- and Trans-Cinnamic Acids Have Different Effects on the Catalytic Properties of Arabidopsis Phenylalanine Ammonia Lyases PAL1, PAL2, and PAL4
Ming-Jie CHEN, Veerappan VIJAYKUMAR, Bing-Wen LU, Bing XIA and Ning LI
J Integr Plant Biol 2005, 47 (1): 67-75.  
doi: 10.1111/j.1744-7909.2005.00002.x
Abstract (Browse 4452)  |   Save
Cis-cinnamic acid (CA) is a naturally occurring compound, presumably converted from trans-CA in higher plants. To investigate the effect of cis-CA on the activity of Arabidopsis phenylalanine ammonia lyase (PAL), AtPAL1, AtPAL2, and AtPAL4 genes were isolated using reverse transcription polymerase chain reaction. These genes were fused to a glutathione S-transferase gene and overexpressed in a heterologous prokaryotic system of Escherichia coli. The purified PAL1, PAL2 and PAL4 enzymes were characterized biochemically to determine the effects of cis-CA on the kinetic parameter Km. The results showed that cis-CA is a competitive inhibitor for PAL1, but not PAL2 and PAL4, whereas trans-CA acts as a competitive inhibitor for all three PAL isomers, suggesting that cis- and trans-CA have different effects on the catalytic activity of PAL.
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The Fusion of Male and Female Nuclei in Fertilization of Higher Plants
Hu Shi-yi and Zhu Cheng
J Integr Plant Biol 1979, 21 (1): null.  
Abstract (Browse 4436)  |   Save
Studies on the fusion of male and female nuclei in fertilization of Helianthus an- nuus L., Triticum aestivan L., Gossypium hisutum L., Hosta caerulea Tratt., and Pinus tabulaeformis Carr. were made in the present work. The results are summarized as follows: 1. The essential process of the fusion of male and female nuclei during syngamy in four species of angiosperms studied may' be generalized as follows: (1) the male nucleus made contact with the female one, (2) followed by the fusion of nuclear membranes between the male and female nuclei. (3) then the despiralization of male spireme happened and male nucleolus made its appearance inside of the fertilized egg nucleus (4) the male chromatin dispersed and make its appearance indistinguishable from that of the female chromatin, (5) the male and female nucleoli fused together to form a larger nucleolus as a sign of completion of the fusion of the two nuclei. In the first mitotic division of the zygote there was only one common mitotic spindle. 2. The essential process of the fusion of egg and sperm nuclei during syngamy in a gymnosperm-Pinus tabulaeformis could also be outlined as follows: (1) the sperm nucleus made contact with the egg nucleue, (2) the fusion of nuclear membranes happened between the male and female nuclei, (3) the male and female ehromatins condensed to form two separate groups of chromatin threads together with the very apparent apperance of the male and female nucleoli at this stage, (4) the male and female chromosomes grouped respectively in their own spindles while both nucleoli disappeared, (5) then the two spindles fused together and all the chromosomes arranged to form a common equatorial plate, (6) finally two daugter nuclei resulted from the mitotic division. 3. Based on the facts that there were two different patterns of the fusion of male and female nuclei in fertilization discribed, all of these accounts are in general accord with the condition usually described that there are two types of fertilization, the pre- mitotic and postmitotie syngamy in higher plants. The type of angiosperm fertilization and the mechanism of promoting the zygote to divide after fertilization are discussed, and the nuclear fusion in sexual reproduction has been compared with that of somatic cell hybridization.
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Recent Advances in Cloning and Characterization of Disease Resistance Genes in Rice
Liang-Ying Dai, Xiong-Lun Liu, Ying-Hui Xiao and Guo-Liang Wang
J Integr Plant Biol 2007, 49 (1): 112-119.  
doi: 10.1111/j.1744-7909.2006.00413.x
Abstract (Browse 4414)  |   Save

Rice diseases caused by fungi, bacteria and viruses are one of the major constraints for sustainable rice (Oryza sativa L.) production worldwide. The use of resistant cultivars is considered the most economical and effective method to control rice diseases. In the last decade, a dozen resistance genes against the fungal pathogen Magnaporthe grisea and the bacterial pathogen Xanthomonas oryzae pv. oryzae have been cloned. Approximately half of them encode nuclear binding site (NBS) and leucine rich repeat (LRR)-containing proteins, the most common type of cloned plant resistance genes. Interestingly, four of them encode novel proteins which have not been identified in other plant species, suggesting that unique mechanisms might be involved in rice defense responses. This review summarizes the recent advances in cloning and characterization of disease resistance genes in rice and presents future perspectives for in-depth molecular analysis of the function and evolution of rice resistance genes and their interaction with avirulence genes in pathogens.Author for correspondence. Tel: +1 614 292 9280; E-mail: wang.620@osu.edu

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Dormancy Breaking and Storage Behavior of Garcinia cowa Roxb. (Guttiferae) Seeds: Implications for Ecological Function and Germplasm Conservation
Yong LIU, Yu-Ping QIU, Ling ZHANG and Jin CHEN
J Integr Plant Biol 2005, 47 (1): 38-49.  
doi: 10.1111/j.1744-7909.2005.00010.x
Abstract (Browse 4393)  |   Save
The dormancy breaking and storage behavior of Garcinia cowa Roxb. seeds were investigated. The seeds of G. cowa had 8–11 months dormancy in their natural habitat. Seeds were matured and dispersed at the end of the rainy season (mid-late August to late September) and were scatter-hoarded by rodents as food for winter after the seeds had fallen to the ground. Seedlings often emerged in the forest during the rainy season (May to August) the following year. Intact seeds of G. cowa failed to germinate after being sown at 30 °C for 120 d and the mean germination time (MGT) of seeds cultured in a shade (50% sunlight) nursery was 252 d. The most effective method of breaking dormancy was to remove the seed coat totally, which reduced the MGT to 13 d at 30 °C. Germination was also promoted by partial removal of the seed coat (excising the hilum and exposing the radicle) and chemical scarification (immersion in 1% H2O2 for 1 d). Unscarified seeds take up water rapidly in the first 96 h, but water was absorbed by the outside seed coat, without penetrating through it. The moisture content (MC) of G. cowa seeds was high (50% in fresh weight) at shedding. The seeds could tolerate desiccation to some extent, until the MC reached approximately 40%; below that, the viability decreases rapidly and all seeds died at approximately 17% of MC. Seed viability decreased rapidly when seeds were chilled at 4 °C; germination was 2% after storage for 1 week. Even stored at 10 °C, seeds began to be damaged after 4 weeks. Seed storage for 1 yr revealed that in both dry (relative humidity (35 ± 5)%) and moist (wet sand) storage conditions, seed viability declined, but germination percentages for seeds stored under moist conditions are better than for seed stored under dry conditions. Because of their low tolerance to desiccation, marked chilling sensitivity and relatively short lifespan, G. cowa seeds should be classified into the tropical recalcitrant category. The ecological implications of dormant recalcitrant seeds and cues on storing recalcitrant seeds were discussed.
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Nitric Oxide Reduces Hydrogen Peroxide Accumulation Involved in Water Stress-Induced Subcellular Antioxidant Defense in Maize Plants
Jianrong Sang, Mingyi Jiang, Fan Lin, Shucheng Xu, Aying Zhang and Mingpu Tan
J Integr Plant Biol 2008, 50 (2): 231-243.  
doi: 10.1111/j.1744-7909.2007.00594.x
Abstract (Browse 4379)  |   Save
Nitric oxide is a bioactive molecule involved in many biological events, and has been reported as prooxidant as well as antioxidant in plants. In the present study, the sources of NO production under water stress, the role of NO in water stress-induced H2O2 accumulation and subcellular activities of antioxidant enzymes in leaves of maize (Zea mays L.) plants were investigated. Water stress induced increases in the generation of NO in maize mesphyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves. Water stress-induced increases in the production of NO were blocked by the pretreatments with inhibitors of NOS and nitrate reductase (NR), suggesting that NO is produced from NOS and NR in leaves of maize plants exposed to water stress. Water stress also induced increases in the activities of the chloroplastic and cytosolic antioxidant enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), and the increases in the activities of antioxidant enzymes were reduced by the pretreatments with inhibitors of NOS and NR. Exogenous NO increases the activities of water stress-induced subcellular antioxidant enzymes, which decreases accumulation of hydrogen peroxide (H2O2). Our results suggest that NOS and NR are involved in water stress-induced NO production and NOS is the major source NO. The potential ability of NO to scavenge H2O2 is, at least in part, due to the induction of subcellular antioxidant defense.
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Relationship Between Embryo and Endosperm Development and Accumulation of Storage Reserves in Barley
Xi Xiang-yuan and Ye Bao-xing
J Integr Plant Biol 1997, 39 (10): null.  
Abstract (Browse 4358)  |   Save
In barley ( Hordeum vulgare L. cv. Aente 13) the zygote with one or two degenerated synergids was seen on day 1 after anthesis but the free nuclear endosperm had not yet appeared. On day 2 and 3 after anthesis the embryo was 5- and 10-celled when the endosperm was at the free nuclear phase. When the embryo was pear- and long pear-shaped by day 4, 5 and 6 after anthesis, the endosperm reached the cellularization stage. The embryo was at the coleoptilar stage and the aleutone initial cells appeared by day 8 after anthesis. When the embryo produced its first leaf on day 10 after anthesis, the aleurone cells formed 1 to 2 layers. On day 13 after anthesis the embryo became 2-leafed as the subaleurone layer occurred. The 3-leafed embryo was visible by day 17 after anthesis, at which time the aleurone cells were mostly 3-layered and mitotic divisions ceased and the prismatic and irregular cells of endosperm were differentiated. On day 21 to 29 after anthesis, the embryo was 4-leafed as the endosperm differentiation continued. The embryo was 5-leafed and matured about the time (33 days after anthesis) when the endosperm also became mature. Starch and protein firstly accumulated in the 2-leafed embryo and deposition proceeded acropetally in the scutellum, but appeared firstly in the apex cells in the coleoptile and leaf primordia. Starch disappeared in the upper part of the mature scutellum. Starch was firstly found in endosperm cells by day 6 after anthesis and on day 10 after anthesis protein deposition began in the aleurone layer and endosperm cells. Aleumne grains formation began on day 21 after anthesis and ended by day 29 after anthesis. From day 17 after anthesis onwards, protein bodies in the endosperm cells were mostly clustered together and markedly decreased afterwards. Lipid accumulation was detected in both seutellum cells and aleurone cells by day 17 after anthesis. Caryopsis length, especially the ratio of caryopsis length to lamma length and scutellum length could be used as the morphological indicators to identify the stages of embryo development and endosperm development as well.
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A Role for Auxin in Flower Development
Youfa Cheng and Yunde Zhao
J Integr Plant Biol 2007, 49 (1): 99-104.  
doi: 10.1111/j.1744-7909.2006.00412.x
Abstract (Browse 4341)  |   Save

Auxin has long been implicated in many aspects of plant growth and development including flower development. However, the exact roles of auxin in flower development have not been well defined until the recent identification of auxin biosynthesis mutants. Auxin is necessary for the initiation of floral primordia, and the disruption of auxin biosynthesis, polar auxin transport or auxin signaling leads to the failure of flower formation. Auxin also plays an essential role in specifying the number and identity of floral organs. Further analysis of the relationship between the auxin pathways and the known flower development genes will provide critical information regarding mechanisms of organogenesis and pattern formation in plants.

Author for correspondence. Tel: +1 858 822 2670; Fax: +1 858 534 7108; E-mail: yzhao@biomail.ucsd.edu

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Analysis of Global Expression Profiles of Arabidopsis Genes Under Abscisic Acid and H2O2 Applications
Peng-Cheng Wang, Yan-Yan Du, Guo-Yong An, Yun Zhou, Chen Miao and Chun-Peng Song
J Integr Plant Biol 2006, 48 (1): 62-74.  
doi: 10.1111/j.1744-7909.2006.00213.x
Abstract (Browse 4320)  |   Save
To gain insight into the coordination of gene expression profiles under abscisic acid (ABA) and H2O2 applications, global changes in gene expression in response to ABA and H2O2 in Arabidopsis seedlings were investigated using GeneChip (Santa Clara, CA, USA) arrays. Among over 24 000 genes present in the arrays, 459 transcripts were found to be significantly increased, whereas another 221 decreased following H2O2 treatment compared with control. Similar to treatment with H2O2, ABA treatment elevated the transcription of 391 genes and repressed that of 322 genes. One hundred and forty-three upregulated genes and 75 downregulated genes were shared between the two treatments and these genes were mainly involved in metabolism, signal transduction, transcription, defense, and resistance. Only two genes, which encode an APETALA2/dehydration-responsive element binding protein (AP2/DREBP) family transcriptional factor and a late embryogenesis-abundant protein, were downregulated by H2O2, but upregulated by ABA. These results suggest that, similar to ABA, H2O2 plays a global role in gene transcription of Arabidopsis seedlings. The transcriptional responses induced by the application of exogenous ABA and H2O2 overlapped substantially. These two treatments regulated most of the downstream genes in a coordinated manner.(Author for correspondence.Tel: 0378 285 5010; Fax: 0378 285 3079; E-mail: songcp@henu.edu.cn)
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Anatomy of the Lithocyst in the Epidermis of Leaf in Broussonetia papyrifera
Yu Fu-gen and Li Zheng-li (Lee Cheng-tee)
J Integr Plant Biol 1991, 33 (4): null.  
Abstract (Browse 4287)  |   Save
This paper deals with the structure, development and composition of the lithocysts and their cystoliths in the epidermis of leaf in Broussonetia papyrifera (L.) Vent. Both epidermal layers had the hair-like lithocysts. The lithocyst seen in the adaxial epidermis had a central hair-like lithocyst with 1–3 rosette-forming small round lithocysts at its base which was absent in the comparatively fine hairy litbocyst on the abaxial epidermis. All these lithocysts had cystoliths. The hair4ike lithocysts in adaxial epidermis developed more quickly, and showed obvious“gliding growth”. One or two stalks were seen clearly in the early stage of the cystolith development. Later, the stalks were covered gradually by the cystolith deposition. The majority of cystoliths were mainly composed of polysaccharides, also mixed with a little suberin and calcium carbonate. But, large variation in material composition was found in different cystoliths and different developmental stages of individual cystolith. Exceptionally, there were large amorphous and shaped crystals of calcium carbonate in the cystoliths of the hair-like lithocysts. The ultrastructure of cystolith components exhibited no orderly arrangement and there was no stratification as seen under optical micoscope.
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Spatio-Temporal Expression Pattern of Six Novel Candidate Genesin Ginsenoside Biosynthesis from Panax ginseng C. A. Meyer
Zhi-Yong LUO, Shui-Ping LIU, Xiang-Hui CHEN, Ying RUAN, Jian-Qing LUO, Bin WEN, Chun-Lin LIU , Wei-Xin HU
J Integr Plant Biol 2005, 47 (5): null.  
DOI: 10.1111/j.1744-7909.2005.00064.x
Abstract (Browse 4258)  |   Save
To explore the mode of the spatio-temporal expression of six newly discovered ginsenoside biosynthesis candidate gene transcripts, both Northern blotting and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) were used to elucidate the mRNA expression levels of the transcripts in various tissues and organs of Panax ginseng C. A. Meyer during different growth development stages. The six gene transcripts were all differentially expressed in cultured callus, root, stem, leaf, and seed. The mRNA expression levels were significantly higher in four-year-old roots than in one-year-old roots, and results of semi-quantitative RT-PCR assays were in accordance with those of Northern blotting analyses. The results strongly suggest that all six genes were differentially expressed at root-specific developmental stages. In particular, when a quiescent early stage culture suspension of P. ginseng cells was exposed to the ginsenoside biosynthesis-promoting elicitor Aspergillus niger polysaccharide, the GBR6 gene transcript response showed time-dependent increments and was parallel with ginsenoside productivity (P < 0.01). Overexpression of the GBR6 gene is likely to play a critically important role in the biosynthesis of ginsenosides. The results of the present study provided a background for the further elucidation of the structure and physiological function of these six candidate genes.
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The Interactions among DWARF10, Auxin and Cytokinin underlie Lateral Bud Outgrowth in Rice
Shuying Zhang, Gang Li, Jun Fang, Weiqi Chen, Haipai Jiang, ,Junhuang Zou, Xue Liu, Xianfeng Zhao, Xiaobing Li, Chengcai Chu, Qi Xie, Xiangning Jiang, and Lihuang Zhu
J Integr Plant Biol 2010, 52 (7): 626-638.  
doi: 10.1111/j.1744-7909.2010.00960.x
Abstract (Browse 4236)  |   Save

Previous studies have shown that DWARF10 (D10) is a rice ortholog of MAX4/RMS1/DAD1, encoding a carotenoid cleavage dioxygenase and functioning in strigolactones/strigolactone-derivatives (SL) biosynthesis. Here we use D10- RNA interference (RNAi) transgenic plants similar to d10 mutant in phenotypes to investigate the interactions among D10, auxin and cytokinin in regulating rice shoot branching. Auxin levels in node 1 of both decapitated D10-RNAi and wild type plants decreased significantly, showing that decapitation does reduce endogenous auxin concentration, but decapitation has no clear effects on auxin levels in node 2 of the same plants. This implies that node 1 may be the location where a possible interaction between auxin and D10 gene would be detected. D10 expression in node 1 is inhibited by decapitation, and this inhibition can be restored by exogenous auxin application, indicating that D10 may play an important role in auxin regulation of SL. The decreased expression of most OsPINs in shoot nodes of D10-RNAi plants may cause a reduced auxin transport capacity. Furthermore, effects of auxin treatment of decapitated plants on the expression of cytokinin biosynthetic genes suggest that D10 promotes cytokinin biosynthesis by reducing auxin levels. Besides, in D10- RNAi plants, decreased storage cytokinin levels in the shoot node may partly account for the increased active cytokinin contents, resulting in more tillering phenotypes.

Zhang S, Li G, Fang J, Chen W, Jiang H, Zou J, Liu X, Zhao X, Li X, Chu C, Xie Q, Jiang X, Zhu L (2010) The interactions among DWARF10, auxin and cytokinin underlie lateral bud outgrowth in rice. J. Integr. Plant Biol. 52(7), 626–638.

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