February 2007, Volume 49 Issue 2, Pages 129-254.


Cover Caption:
Tree ring and climate change
Annual growth of the tree ring is an important indicator of climate changes and eco-disturbance. The cover shows the growth rings of the secondary root of Cymbaria dahurica L. The size and orientation of cells and vessels contribute to the delineation of growth rings. The wider vessels at the beginning of growing season are earlywood, while the narrower vessels in the late growing season are latewood. This structure could be used for the studies of climate and grassland ecology. See pages 144-149 for more details.

 

          Hot Topic
Tree Rings and Ecology: The 7th International Conference on Dendrochronology
Author: Qi-Bin Zhang and Xuemei Shao
Journal of Integrative Plant Biology 2007 49(2): 129-130
DOI: 10.1111/j.1744-7909.2007.00448.x
      
    Tree rings have long been recognized as a useful indicator of past environmental changes. Besides traditional applications in studies of climate change and archaeology, the technique of dendrochronology has been widely used in answering ecological questions. This has been partly reflected by the broad topics on tree rings and ecology presented at the 7th International Conference on Dendrochronology (ICD), which was held in Beijing, June 11C17 2006. At this conference, Dr Henri Grissono-Mayer, the plenary speaker for the theme, defined dendroecology as the science that uses tree rings, dated to their exact year of formation, to analyze temporal and spatial relationships between living organisms and their environment. The five papers included in this issue of the Journal were selected from the 7th ICD presentations that addressed applications of dendrochronological techniques in different aspects of ecological studies. The paper by Du and Yamamoto (page 131−143) presents a review of the biology of reaction wood formation and its recent research progress. Knowledge of the types of reaction wood and the mechanisms of their development is useful for interpreting such tree-ring features from the viewpoint of environmental events and their influences.The paper by Campbell et al. (page 168−178) addresses the disturbance ecology of forest insect activities through investigating mountain pine beetle outbreaks in central British Columbia, Canada. Their results provide evidence that radial growth releases in surviving host trees match data from aerial surveys of mountain pine beetle outbreaks when taking into account the climate and stand characteristics. Liu et al. (page 150−156) tackle the hydroecology of Oasis forest trees by studying the radial growth of Populus euphratica trees in the lower reaches of the Heihe Basin, Northwestern China. The results are particularly useful for management of water resources and protection of oasis forests in this region of frequent water shortages. Lin et al. (page 157−167) touch on conservation ecology by conducting dendroecologyical analyses of the age distribution and growth dynamics of an endangered tree species (Amentotaxus formosana Li) in Taiwan. The fifth paper, by Liu and Zhang (page 144−149), reports the characteristics of growth rings in the main roots of perennial forb species from Inner Mongolian grasslands in northern China, demonstrating the feasibility of using herb chronology for studies of climate change and disturbance effects in grasslands. The topics of the above five papers represent only a small part of the research fields in dendroecology. At the 7th ICD, 76 oral presentations and 35 posters touched on different aspects of the field of dendroecology(detailed information of the sessions, presentations and posters can be found at the conference website, http://7thicd.ibcas.ac.cn). However, compared to active research in the world, dendroecological study in China is very weak. Given that China is currently in a stage of rapid economic development and that the global climate continues to change, we propose that future dendroecological studies in China should receive more attention in the following areas: (i) understanding disturbance regimes, such as droughts, flooding, fire and insect outbreaks, and their relationships with changing climates in typical forest types; (ii) conducting interdisciplinary studies(such as ecology, climatology and hydrology) to understand better the effects of global change on forests as well as the interactions among different factors that shape landscapes; (iii) communication with personnel in forestry management to apply dendroecologial techniques and theories for answering questions in practical management; and (iv) dissemination of ecological and environmental knowledge to the public from the viewpoint of dendroecology. We would like to end this introductory article by expressing our thanks to the editors of the Journal of Integrative Plant Biology for agreeing to and assisting in the publication of the selected papers in the Journal.Our thanks extend to the Institute of Botany of the Chinese Academy of Sciences (CAS) for organizing and hosting the conference, the Tree-Ring Society, the Association of Tree-Ring Research, and the Tree-Ring Working Group of the International Union of Forest Research Organization for support and assistance in the organization of the conference. We are grateful to PAGES, Tree-Ring Society, National Natural Science Foundation of China, State Ministry of Education of China, CAS and CASs Key Laboratory of Quantitative Ecology at the Institute of Botany for their financial support of the conference. We thank the 272 registered participants and a number of uncounted others from 35 countries and regions for attending the conference. We also thank the conference committee members for their efforts in making the conference a success. We hope that the tree-ring and ecology presentations at the conference and the selected papers in this issue will stimulate interest in the broad areas of dendroecological research in the future. Particularly, we hope there will be a growing number of presentations on Chinas dendroecological research at the 8th International Conference on Dendrochronology that will be held in Rovaniemi, Finland in 2010.
Abstract (Browse 3722)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Invited Expert Reviews
An Overview of the Biology of Reaction Wood Formation  
Author: Sheng Du and Fukuju Yamamoto
Journal of Integrative Plant Biology 2007 49(2): 131-143
DOI: 10.1111/j.1744-7909.2007.00427.x
      
    Reaction wood possesses altered properties and performs the function of regulating a trees form, but it is a serious defect in wood utility. Trees usually develop reaction wood in response to a gravistimulus. Reaction wood in gymnosperms is referred to as compression wood and develops on the lower side of leaning stems or branches.In arboreal, dicotyledonous angiosperms, however, it is called tension wood and is formed on the upper side of the leaning. Exploring the biology of reaction wood formation is of great value for the understanding of the wood differentiation mechanisms, cambial activity, gravitropism, and the systematics and evolution of plants. After giving an outline of the variety of wood and properties of reaction wood, this review lays emphasis on various stimuli for reaction wood induction and the extensive studies carried out so far on the roles of plant hormones in reaction wood formation. Inconsistent results have been reported for the effects of plant hormones. Both auxin and ethylene regulate the formation of compression wood in gymnosperms. However, the role of ethylene may be indirect as exogenous ethylene cannot induce compression wood formation. Tension wood formation is mainly regulated by auxin and gibberellin. Interactions among hormones and other substances may play important parts in the regulation of reaction wood formation.
Abstract (Browse 2932)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Plant Terpenoids: Biosynthesis and Ecological Functions  
Author: Ai-Xia Cheng, Yong-Gen Lou, Ying-Bo Mao, Shan Lu, Ling-Jian Wang and Xiao-Ya Chen
Journal of Integrative Plant Biology 2007 49(2): 179-186
DOI: 10.1111/j.1744-7909.2007.00395.x
      
    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
Abstract (Browse 6743)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Research Articles
Growth Rings of Roots in Perennial Forbs in Duolun
Author: Yong-Bo Liu and Qi-Bin Zhang
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00426.x
      
    Annual growth rings of roots in perennial forbs have been used in studies of climate change and the ecology of grasslands. However, little has been done in this aspect of research in China. In this study, we report the characteristics of growth rings in the main roots of 13 herb species sampled in Duolun of the Inner Mongolia grassland in northern China. The results show that around two thirds of the species possess clearly demarcated annual rings in the root xylem. Some species of the same genera show different patterns in anatomical structure of the root xylem. Standardized annual ring widths of three species, Potentilla anserine L., Cymbaria dahurica L. and Lespedeza daurica (Laxm.) Schindl., show a common linear trend, indicating a continued favorable growth condition in the sampling sites. Our results provide evidence that growth rings in roots of some perennial forbs in the Inner Mongolia grassland can serve as a new and useful indicator of past changes in the grassland environment.
Abstract (Browse 2135)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Hydrological Response of Populus euphratica Olve.Radial Growth in Ejinaa Banner, Inner Mongolia
Author: Pu-Xing Liu, Jian-Feng Peng and Fa-Hu Chen
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00425.x
      
    Populus euphratica Olve. is a dominant tree species in Ejinaa Oasis of the lower reaches of the Heihe River, Inner Mongolia, China. In recent years, the population of this species has shown signs of degradation that are suggested to be probably associated with the decrease of surface water. In this study, the history of river runoff in this region was examined with a drochronological study of P. euphratica from four sites. It is found that tree-ring widths in the all sites have negative correlation with runoffs of all months at the Zhengyixia hydrological station. Principal component (PC) analysis of the tree-ring chronologies shows that the first PC (PC1) accounts for 49.98% of the total variances. The first PC is found to have a significantly negative correlation with runoffs in March and April (C 0.52 and C 0.43, respectively, P < 0.05). This negative correlation might be related to variations in the depth of underground water.
Abstract (Browse 2051)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Age Structure and Growth Pattern of an Endangered Species, Amentotaxus formosana Li
Author: Chinsu Lin, Ming-Hsun Chan, Feng-Sheng Chen and Ya-Nan Wang
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00429.x
      
    Amentotaxus formosana Li is a native, tolerant, and under-wood species in Taiwan. This particular species is only distributed around the Chachayalaishan and Dawushan areas. Because of its rarity, and the endangered and native properties of the species, we explored the regeneration process of the species in the native environment. This paper, therefore, aims to outline the age distribution and growth characteristics of A. formosana in the native stand using the techniques of tree ring analysis. An inventory was conducted in a site at the Chachayalaishan area from 2004 to 2006. According to the inventory, there are 67 trees in the sampling plot among which 16 individual A. formosana trees were counted. This is roughly 24% of the total population. This particular species is distributed around the understory space, while other species such as Litsea spp., Meliosma squamulata Hance, Schefflera octophylla Harms, Elaeocarpus japonicus Sieb et Zucc and Cleyera japonica Thunb are the major species whose canopy occupying the upperstory space of the stand. Results of tree-ring analysis suggest that the age of most of the trees in the sampling plot is between 31 and 90 years old with an average of 56. For the endangered species, A. formosana, age of the individuals varied from 14 and 126 years old and the average was 58 years old. Age distribution of the species was modeled using the Weibull probability density function and was statistically assessed using Sigmaplot statistical software. The estimate of shape parameter is 1.404 5 indicating a medium regeneration situation. The diameter growth rate of A. formosana is 0.32 cm and ranks 20th among the 26 species in the sampling plot. Using the age as a regressor variable, we can predict the diameter increment of A. formosana efficiently. The coefficient of determination, R2, is 0.832 2. The diameter growth among the trees of the upperstory and understory was competitive. Relationship between the growth change percentage of A. formosana and the surrounding hardwoods is negative.
Abstract (Browse 2024)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Spatial Distribution of Mountain Pine Beetle Outbreaks in Relation to Climate and Stand Characteristics: A Dendroecological Analysis
Author: Elizabeth M. Campbell, Ren I. Alfaro and Brad Hawkes
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00423.x
      
    Principal components analysis, followed by K-means cluster analysis, was used to detect variations in the timing and magnitude of Pinus contorta Dougl. ex Loud. growth releases attributed to mountain pine beetle outbreaks in 31 stands of central British Columbia. Four major growth release patterns were identified from 1970 to 2000. Variations in the timing of growth releases among clustered stands corresponded well to aerial survey data indicating the timing of beetle outbreaks in the study area. Redundancy analysis was used to determine how variations in the timing and magnitude of growth releases attributed to beetle outbreaks changed with variations in climate or stand conditions over the study area. The first RDA axis, which accounted for 39% of the variations in growth patterns among stands, was significantly (P<0.05) correlated with gradients in the percentage of pine in stands killed by mountain pine beetle, summer aridity, variation in summer precipitation, distance from initial infestation site, average pine age, and maximum August temperatures. The second RDA axis explained 6% of the variations and was significantly correlated with gradients in the beetle climate suitability index, extreme cold month temperatures, and site index. Comparisons of growth release patterns with aerial survey data and redundancy analyses indicated that dendrochronological techniques are useful for identifying mountain pine beetle outbreaks in central British Columbia, particularly among stands that had a density high enough to produce a growth release signal. Provided future studies account for interannual weather fluctuations, identification of growth increases due to stand thinning caused by beetle outbreaks will be useful for reconstructing the history of beetle outbreaks over much longer time periods.
Abstract (Browse 2057)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Stress & Phytochemistry
Protein Changes in Response to Pyrene Stress in Maize (Zea mays L.) Leaves
Author: Sheng-You Xu, Ying-Xu Chen, Wei-Xiang Wu, Shao-Jian Zheng, Sheng-Guo Xue, Shi-Ying Yang and Yi-Jin Peng
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00284.x
      
    Phytoremediation is a relatively new approach to remove polycyclic aromatic hydrocarbons (PAHs) from the environment. When plants are grown under pyrene treatment, they respond by synthesizing a set of protective proteins. To learn more about protein changes in response to pyrene treatment, we extracted total proteins from the leaves of maize (Zea mays L.) 1 week after pyrene treatment. The proteins extracted were separated with twodimensional gel electrophoresis. In total, approximately 54 protein spots were found by comparing gels from treated and control groups. According to the isoelectric point, molecular weight, and abundance of these protein spots, 20 pyrene-induced proteins were found to have changed abundance. Of these, 15 protein spots were increased and five protein spots were newly appeared in pyrene-treated plant leaves. Six model upregulated protein spots of different molecular weights were excised from the gels and subjected to trypsin digestion followed by peptide separation using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Peptide masses were used to search the matrix-science database for protein identification. Two of the proteins were identified on the basis of the homology of their peptide profiles with existing protein sequences as pyruvate orthophosphate dikinase and the ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit. These proteins are involved in the regulation of carbohydrate and energy metabolism. The present study gives new insights into the pyrene stress response in maize leaves and demonstrates the power of the proteomic approach in phytoremediation of PAHs
Abstract (Browse 2171)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Two New Triterpenoid Saponins from Akebia quinata (Thunb.) Decne.
Author: Gui-Yan Liu, Shuang-Cheng Ma, Jian Zheng, Ji Zhang and Rui-Chao Lin
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00362.x
      
    Two new triterpenoid saponins, hederagenin 3-O--L-arabinopyranosyl-(12)--L-arabinopyranoside named akeboside La (compound 1), oleanolic acid 3-O--L-arabinopyranosyl-(12)--D-glucopyranoside named akeboside Lb (compound 2), along with five known saponins, oleanolic acid 3-O--L-rhamnopyranosyl-(12)--Larabinopyranoside (compound 3), hederagenin 3-O--L-rhamnopyranosyl-(12)--L-arabinopyranoside (compound 4), oleanolic acid 3-O--D-xylopyranosyl-(13)--L-rhamnopyranosyl-(12)--L-arabinopyranoside (compound 5), 3-O--L-rhamnopyranosyl-(12)--L-arabinopyranosyl oleanolic acid 28-O--L-rhamnopyranosyl-(14)--Dglucopyranosyl-( 16)--D-glucopyranoside (compound 6), 3-O--L-rhamnopyranosyl-(12)--L-arabinopyranosyl hederagenin 28-O--L-rhamnopyranosyl-(14)--D-glucopyranosyl-(16)--D-glucopyranoside (compound 7) were isolated from the n-butanol part of the 80% ethanol extracts of the dried stems of Akebia quinata (Thunb.) Decne. Compound 5 was isolated from plants of genus Akebia for the first time. The structures were elucidated on the basis of physicochemical properties and spectral data.
Abstract (Browse 1854)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Triterpenoid Saponins from Pulsatilla cernua (Thunb.)
Author: Tun-Hai Xu, Ya-Juan Xu, Dong Han, Hong-Feng Zhao, Sheng-Xu Xie and Dong-Ming Xu
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00339.x
      
    To investigate saponins from the roots of Pulsatilla cernua (Thunb.) Bercht. et Opiz., two new compounds together with five known triterpenoid saponins were isolated. The structures of the two new triterpenoid saponins, named cernuasides A and B, were elucidated as 3-O-[-D-xylopyranosyl(12)]-[-L-rhamnopyranosyl(14)]--Larabinopyranosyl hederagenin 28-O--D-glucopyranosyl ester (compound 1) and 3-O-[-L-arabinopyranosyl(13)]-[-L-rhamnopyranosyl (12)]--L-arabinopyranosyl hederagenin 28-O--D-glucopyranosyl ester (compound 2) by 1D, 2D-NMR techniques, ESIMS analysis, as well as chemical methods.
Abstract (Browse 1632)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Biotransformation of 4-Hydroxybenzen Derivatives by Hairy Root Cultures of Polygonum multiflorum Thunb.
Author: Chun-Yan Yan, Rong-Min Yu, Zhang Zhang and Ling-Yi Kong
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00400.x
      
    The biotransformation of four 4-hydroxybenzen derivatives (1,4-benzenediol (compound 1), 4-hydroxybenzaldehyde (compound 2), 4-hydroxybenzyl alcohol (compound 3) and 4-hydroxybenzoic acid (compound 4)) by the hairy root cultures of Polygonum multiflorum Thunb. as a new biocatalyst was investigated. It was found that the substrates were transformed to their corresponding glucosides, 4-hydroxyphenyl -D-glucopyranoside (arbutin, compound 1a), 4-hydroxymethylphenyl -D-glucopyranoside (gastrodin, compounds 2a, 3a) and 4-carboxyphenyl -Dglucopyranoside (compound 4a), respectively. In the meantime, the hairy roots of P. multiflorum were able to stereoselectively and regioselectively glucosylate phenolic hydroxyl groups of compounds 1C4, but the cultures could not glucosylate the aldehyde group of compound 2 or the benzylic hydroxyl group of compound 3, and no glucosyl esterification of carboxyl groups of compound 4 was detected. On the other hand, the result also showed that the hairy roots of P. multiflorum were able to reduce the 4-hydroxybenzaldehyde to its corresponding alcohol. This is the first report that substrate 4 has been converted into its -D-glucopyranoside by a plant biotransformation system.
Abstract (Browse 1663)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
New Isoflavonoid Glycosides from the Rhizomes of Iris leptophylla Lingelsh.
Author: Min-Jian Qin, Rong Li, Xin Wang and Wen-Cai Ye
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00378.x
      
    Two new isoflavonoid glucosides, 5-hydroxy-6,7-methylenedioxy-isoflavone-4''-O-D-glucopyranosyl (21)-L-rhamnoside (irilone-bioside) (compound 1) and 5,4''-methoxy-6,7-methylenedioxyisoflavone-3''-O--D-glucoside (irisleptophyllidin) (compound 2), together with five known compounds, nigricanin- 4''-O--D-glucoside (compound 3), irifloside (compound 4), irigenin (compound 5), 5, 3'', ''-trimethoxy-6,7-methylenedioxyisoflavone (compound 6), and nigricanin (compound 7) were isolated from the alcoholic extract of rhizomes of Iris leptophylla Lingelsh. Their structures were elucidated by pectroscopic methods.
Abstract (Browse 1792)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Two New Coumarins from Fraxinus chinensis Rexb.
Author: Dong-Mei Zhang, Li-Li Wang, Jia Li and Li-Hong Hu
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00340.x
      
    The ethanol extract of the stem bark of Fraxinus chinensis Roxb. showed good inhibitory bioactivity against VEGF receptor-1 kinase (IC50: 13.8 g/mL). In order to find new and bioactive compounds, the chemical constituents of the stem bark of F. chinensis were investigated and two new coumarins, namely 6'-O-sinapinoyl esculin (compound 1) and 6'-O-vanillyl esculin (compound 2), together with eleven known compounds (compounds 3C13) were isolated.The structures of the two new compounds were identified by their physicochemical properties and spectral analysis, particularly one- and two-dimensional nuclear magnetic resonance spectral methods. The known compound, oleuropein (compound 11), exhibited moderate activity (IC50: (8.7 1.3) mol/L) to inhibit VEGF receptor-1 kinase.
Abstract (Browse 1525)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Omics & Epigenetics
Varied Transcriptional Efficiencies of Multiple ArabidopsisU6 Small Nuclear RNA Genes
Author: Xia Li, Dan-Hua Jiang, Kelan Yong and Da-Bing Zhang
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00393.x
      
    Arabidopsis U6 small nuclear RNA (snRNA) promoters are those transcribed by RNA polymerase III, but all the core elements for transcriptional initiation are located in the 5'' promoter region. Previously, three Arabidopsis U6 snRNA genes (U6-1, U6-26, and U6-29) were identified. Herein, we have further identified three new U6 loci (U6-4, U6-5, and U6-6) in the Arabidopsis genome. Alignment of these revealed that the upstream sequence element and TATA elements were contained in six U6 promoters. In addition, a unique, highly conserved element named the CAT element was observed in the promoter region. To understand the expression patterns of these U6 genes in Arabidopsis, we fused these promoters to the DNA segment of -glucuronidase and then transferred these six constructs into Arabidopsis. Real-time reverse transcription-polymerase chain reaction analysis of these fused transcripts indicated that the newly identified U6 genes are active in Arabidopsis and that the U6-26 promoter seems to have higher transcriptional activity in leaf, stem, flower and silique. These results help to understand the function of these U6 snRNAs in Arabidopsis.
Abstract (Browse 2465)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Signal Transduction
Overexpression of OsJAC1, a Lectin Gene, Suppresses the Coleoptile and Stem Elongation in Rice
Author: Jia-Fu Jiang, Yun-Yuan Xu and Kang Chong
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00428.x
      
    Lectin plays an important role in defense signaling in plants, but its function in plant growth and development is not well known. Previously, we cloned a rice (Oryza sativa L.) gene OsJAC1 encoding a mannose-binding jacalin-related lectin, and found that OsJAC1 was jasmonic acid (JA) inducible. Here we cloned the promoter of OsJAC1, and GUS activity was detected in young roots, coleoptiles, sheaths, leaves, nodes of stems, stems, rachises, pistils, stamens and lemmas of OsJAC1::GUS transgenic rice, suggesting that OsJAC1 is a constitutive expression gene in rice. Moreover, OsJAC1-overexpressed (Ubi::OsJAC1) rice showed dwarfism with shorter coleptiles resulting from the failure of cell elongation of coleoptiles. In addition, compared with coleoptiles of wild-type plants, those of OsJAC1 overexpression rice were more sensitive to JA treatment. These data revealed that, besides its roles in defense response, lectin plays an important role in rice growth and development.
Abstract (Browse 1675)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Evolution
Pollen-Ovule Ratio and Gamete Investment in Pedicularis (Orobanchaceae)
Author: Chun-Feng Yang and You-Hao Guo
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00398.x
      
    The Pedicularis species provides ideal materials to study floral evolution because of their substantial flower variation based on a narrow genetic basis, even though they are almost exclusively pollinated by bumblebee. These traits allow us to detect the evolutionary trends of floral parameters without onsidering genetic background and the difference of pollination vectors. The pollen-ovule ratio is widely used to estimate the pattern of resource nvestment in two sexual functions in flowering plants. Forty species epresenting all of the corolla types in Pedicularis were used to study pollen-ovule ratio, gamete investment, and their correlations. Results show that pollen-ovule ratio does not differ among both different corolla types and taxonomic groups. It is therefore suggested that pollen-ovule ratio should be a parallel evolution. The correlations between pollen-ovule ratio and pollen size (C),and ovule size (+) can be successfully explained in terms of sex allocation theory. The biological significance of such relationships was also discussed. Additionally, we analyzed the pattern of resource investment into female gamete, which has been somewhat neglected, and found that plants have different patterns of gamete investment between the two sexual functions. .
Abstract (Browse 1836)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Comparative Analysis of Codon Usage Patterns Among Mitochondrion, Chloroplast and Nuclear Genes in Triticum aestivum L.
Author: Wen-Juan Zhang, Jie Zhou, Zuo-Feng Li, Li Wang, Xun Gu and Yang Zhong
Journal of Integrative Plant Biology 2007 49(2)
DOI: 10.1111/j.1744-7909.2007.00404.x
      
    In many organisms, the difference in codon usage patterns among genes reflects variation in local base compositional biases and the intensity of natural selection. In this study, a comparative analysis was performed to investigate the characteristics of codon bias and factors in shaping the codon usage patterns among mitochondrion,chloroplast and nuclear genes in common wheat (Triticum aestivum L.). GC contents in nuclear genes were higher than that in mitochondrion and chloroplast genes. The neutrality and correspondence analyses indicated that the codon usage in nuclear genes would be a result of relative strong mutational bias, while the codon usage patterns of mitochondrion and chloroplast genes were more conserved in GC content and influenced by translation level.The Parity Rule 2 (PR2) plot analysis showed that pyrimidines were used more frequently than purines at the third codon position in the three genomes. In addition, using a new alterative strategy, 11, 12, and 24 triplets were defined as preferred codons in the mitochondrion, chloroplast and nuclear genes, respectively. These findings suggested that the mitochondrion, chloroplast and nuclear genes shared particularly different features of codon usage and evolutionary constraints.
Abstract (Browse 1935)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
 

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