September 1999, Volume 41 Issue 9

 

          Research Articles
An Insight into Paleovegetation on the Emerged Shelf at the Last Glaciation: Pollen Date of the South China Sea
Author: SUN Xiang-Jun, CHEN Xu-Dong, LUO Yun-Li and LI Xun
Journal of Integrative Plant Biology 1999 41(9)
      
    Vegetation on the emerged continental shelves of the South China Sea (SCS) during the Last Glacial Maximum (LGM) was deduced based on pollen of hemipelagic sediments from the continental slopes and the consideration of pollen transport dynamics and source areas. During the LGM (including the top of Oxygen Isotope Stage 3) the sea level might be more than 100 m lower than that of the present. Consequently, both northern and southern continental shelves of the SCS were exposed. The northern continental shelf was covered by grassland mainly of Artem/s/a. The climate should be cold and dry, whereas on the southern continental shelf (Sunda Land) was spread tropical lowland rainforest and mangroves were scattered by the river mouths and along the coast. The climate might be cooler than that in the present day, but drop of humidity was not observed.
Abstract (Browse 1577)  |  Full Text PDF       
Characteristics and Conservation Priority of Rare and Endangered Plants in the Yangtse River Valley
Author: XIE Zong-Qiang and CHEN Wei-Lie
Journal of Integrative Plant Biology 1999 41(9)
      
    127 rare and endangered species listed in ¡¶China Plant Red Data Book¡· were found in Yangtse River valley. 1/3 of them belonged to 4 families with high economic values such as Pinaceae, Magnoliaceae, Lauraceae and Ranuculanceae. Of all the plants, 66.93 % existed in forests and 71.65 % were threatened with damage of habitats. The rare and endangered plants in the studied region formed a geographical pattern with 2 distribution areas and 6 small distribution centers. The 2 areas were in the high mountains in western Sichuan and northern Yunnan or around the Sichuan Basin. The 6 centers included the fragmented montane forests in the eastern part of the valley. These showed that human activities were the main factor threatening the survival of plants, and preserving forests were the effective approach to save the rare and endangered plants in the valley. Takings¡Ü 10 as the number of population in a unit of area for categorizing the endangered plants is basically in accord with the criterion defined in the ¡¶China Plant Red Data Book¡·. Thus the rare and endangered plants in the valley could be divided into 5 ranks for priority conservation. The plants in the first rank composed cf 8 endemic species natively grown the valley with only one population for which effective measures should be taken for active preservation.
Abstract (Browse 1678)  |  Full Text PDF       
Anatomical Characteristics of Leaves and Woods of Fagus lucida and Their Relationship to Ecological Factors in Mountain Fanjingshan, Guizhou, China
Author: FEI Song-Lin, FANG Jing-Yun, FAN Yong-Jun, ZHAO Kun, LIU Xue-Jiao and CUI Ke-Ming
Journal of Integrative Plant Biology 1999 41(9)
      
    An eco-anatomic study on leaves and woods of Fagus lucida Rehd. et Wils., which grows at an elevation of 1 260¡«2 020 m above sea level in Mountain Fanjingshan, Guizhou Province of Southwestern China, was carried out. Anatomical characteristics of leaves (including the thickness of upper epidermis, palisade mesophyll, spongy mesophyll, lower epidermis and lamina) and woods (vessel length, vessel width, vessel frequency, fiber length, ray width, ray height and ray frequency), and leaf surface characters (stomatal density, stomatal width and stomatal length) were determined and compared along the latitudinal gradient. As the results, 1) Lamina thickness was between 119.2 and 364.3¦Ìm; 2) Vessel frequency 75.2¡«133.6 per mm , vessel width 50.7¡«85.6 ¦Ìm, vessel length 479.8¡«748.6 ¦Ìm; fiber length 936.4¡«1 326.9 ¦Ìm; total frequency of single and muhiseriate rays 6¡«9 per mm; 3) No solitary trichome was found on mature foliage, and the stomatal density was 72¡«113.6 per mm . Climatic indices at different altitudes were obtained by means of climatological method. Multi-statistical analysis was used to clarify the relationship between the morphological characters of the leaves and woods and climatic factors. The results showed that: 1 ) The thickness of palisade mesophyll, lower epidermis and lamina, and the vessel width increased with the humid/ add index (Bailey¡¯s index); 2) With an increase of annual precipitation, spongy mesophyll thickness, vessel length and fiber length increased, but vessel frequency and stomatal density decreased; 3) Morphological features of leaves were closely related to low winter temperature, namely, lamina thickness decreased with coldness index, and the stomatal size decreased as the increase of mean temperature of the coldest month.
Abstract (Browse 1855)  |  Full Text PDF       
Discovery of Paratingia and Paratingiostachya from the Shanxi Formation of the Early Early Permian in the Wuda Area of Inner Mongolia, China
Author: SUN Ke-Qin, DENG Sheng-Hui, CUI Jin-Zhong and SHAN Ping
Journal of Integrative Plant Biology 1999 41(9)
      
    Specimens of Paratingia and Paratingiostachya were collected from the Shanxi (Shansi) Formation of the early Early Permian in the Wuda area of Inner Mongolia, China, including Paratingia datongensis Zhang and Paratingiostachya cathaysiana gen. et sp. nov. A pair of specimens of Paratingiostachya are well preserved together with those of Paratingia datongensis, which show Paratingiostachya in close association with Paratingia datongensis. Therefore, Paratingiostachya cathaysiana gen. et sp. nov. probably is referred to the reproductive organ of Paratingia datongensis. The discovery of Paratingiostachya cathaysiana gen. Et sp. nov. may provide some important evidences for the geographical distribution, classification and evolution of the genus Paratingia.
Abstract (Browse 1726)  |  Full Text PDF       
Chemical Constituents of the Roots of Maackia tenuifolia (Leguminosae)
Author: ZENG Jia-Feng and ZHU Da-Yuan
Journal of Integrative Plant Biology 1999 41(9)
      
    Three new con,pounds (2R,3R)-2' ,4'-dihydroxymaackiaflavanonol (1), maackiaphenone (2), 4-( 1,2-dimethyl-2-propenyl)- 1,3-dihydroxybenzene (3) along with ten known compounds euchrenone a7 (4),maackiaflavanonol (5), 1-medicarpin (6), fomononetin (7), di-O-methyldaidein (8), genistein (9), 7-drimen- 11-ol (10), methyl-3,4, 5-trimethoxycinnamate ( 11 ),¦Â-sitosterol ( 12 ), piceatannol (13), wereisolated from the CH2C12-soluble portion of the ethanolic extract of the roots of Maackia tenuifolia ( Hemsl. )Hand.-Mazz. (keguminosae). Their structures were established by spectroscopic methods. All the compounds except 5, 7 and 8 were isolated from this plant for the first time.
Abstract (Browse 1851)  |  Full Text PDF       
Changes of Photosystem ¢ò and Respiratory Enzyme Activity in Transgenic Tobacco Enriched BADH Gene
Author: YI Yan-Jun, LIU Jia-Yao, LUO Ai-Ling, ZHANG Qi-De, MA De-Qin, WNAG Xue-Chen and LIANG Zheng
Journal of Integrative Plant Biology 1999 41(9)
      
    The transient characteristics of chlorophyll fluorescence induction, the activities of respiratory enzymes (malate dehydrogenase, isocitrate dehydrogenese, suecinate dehydrogenase and cytochrome C oxidase) and the activities of photorespiratory enzymes (hydroxypyruvate reductase, glycolate oxidase and catalase) in the transgenic tobacco (Nicotiana tabacum L. ), in which betaine aldehyde dehydrogenase (BADH) gene had been introduced, were determined and compared with the parent plants. The results showed that the Fy/Fo, Fv/Fm and Fd/Fs of the transgenic plant had no changes; the activities of ma]ate dehydrogenase, isocitric dehydrogenase and succinic dehydrogenase in tricarboxylic acid cycle had a slight increase, and the activity of eytochrome C oxidase in the terminal oxidative pathway had a significant increase. The activities of hydroxypyruvate reductase, glycol]ic oxidase and catalase in the photorespiratory pathway had a marked increase. The possible significance on these changes was discussed.
Abstract (Browse 1645)  |  Full Text PDF       
Selective Fractionation of Maize Sperm Cells by RCA I Sepharose 6MB Affinity Chromatography
Author: XU Heng-Ping, JIN Cheng, YANG Shou-Jun, ZHANG Shu-Zheng and TSAO T H
Journal of Integrative Plant Biology 1999 41(9)
      
    RCA I-Sepharose 6MB was employed for affinity chromatography of maize ( Zea mays L. ) sperm cells. The result indicates that the loading capacity of 0.1 mL RCA I-6MB is about 1.5 ¡Á 10 . If the amount of sperm cells is less than this capacity, about 70% of the sperm cells specifically bind to RCA I-6MB. 42.1% of the absorbed sperm cells can be released from RCA I-6MB in 0.2 mol/L galactose and recovered with less impurities and with some viability, which will facilitate further study on plant sperm cells. It remains to be elucidated whether there are two types of maize sperm cells different from each other in monosaccharide residues on their plasma membranes.
Abstract (Browse 1632)  |  Full Text PDF       
Studies on the Nucleic Acid and Protein Content in the Cotyledon Cells of Lotus Using Fluorescent Imaging System with a Scientificª²grade Charge Coupled Device
Author: LI Su-Wen, CUI Jian-Sheng, LIU Jin-Ying, WANG Chen, TANG Pei-Hua and XUE Shao-Bai
Journal of Integrative Plant Biology 1999 41(9)
      
    Enzyme dissociated cotyledon cells were obtained from red lotus ( Nelumbo sp. ) on the 5th day and 20th day after fertilization respectively. DNA, RNA and total protein content of individual 5 d and 20 d cell were measured correlatively by microfiuorescent imaging system with a cooled scientific-grade Charge coupled deviced (CCD) camera. The results showed that DNA content of the 20 day cell has become polyploidized from 4C to 8C approximately. The window analysis indicated that relative content of RNA and total protein of the 20 day cell was more than 11 times that of the 5 day cell in the same 4C DNA window respectively. The multiple in-creased of RNA and total protein content was about the same as that of DNA in 2 DNA windows (4C and 8C) of the 20 day cell. These data showed that the enormous accumulation of storage proteins in the cotyledon cells of red lotus depends on both DNA ploidy and selective expression of the subunit genes of the storage proteins during the developmental process.
Abstract (Browse 1580)  |  Full Text PDF       
Studies on the Salicylic Acid Inducted Lipid Peroxidation and Defense Gene Expression in Tobacco Cell Culture
Author: YU Di-Qiu, CEN Chuan, YANG Ming-Lan and LI Bao-Jian
Journal of Integrative Plant Biology 1999 41(9)
      
    Salicylic acid (SA) could inhibit catalase activity, induce rapid lipid peroxidation and PR-1 gene expression of the tobacco ( Nicotiana tabacum L. ) cell culture which was incubated with exogenous SA. ¦±-ihydroxybenzene and H2O2 could also induce lipid peroxidation and PR-1 gene expression at different level, but they were not able to inhibit the catalase activity of tobacco cells. Inhi0itors of mRNA and protein-synthesis (a-amanitine and cycloheximide, respectively) could not induce both lipid peroxidation and PR-1 gene expression of tobacco cell culture. However, coordinated action with SA respectively, a-amanitine or cycloheximide was able to induce lipid peroxidation effectively, but strongly blocked the activation of PR-1 gene expression by SA in tobacco cell culture. These results suggested that the generation of reactive metabolites or free radicals, which were induced by SA or other inducers through reaction with catalase or other compounds, initiated lipid peroxidation, subsequently activated pathogen-resistance genes expression. Obviously the lipid peroxidation molecule played an important role in SA signal transduction in tobacco.
Abstract (Browse 1687)  |  Full Text PDF       
Isolation of Glycoproteins from Verticillium dahliae and Their Phytotoxicity
Author: CHU Zhao-Qing,JIA Jun-Wei, ZHOU Xiang-Jun and CHEN Xiao-Ya
Journal of Integrative Plant Biology 1999 41(9)
      
    Verticillium dahliae Kleb. is a phytopathogenic fungus that causes cotton wilt-disease. Glycoproteins secreted by V. dahliae have been found to play an important role in wilting syndrome. In this study the glycoproteins were purified consecutively by ConA-Sepharose 4B affinity chromatography, Sephadex G-150 gel filtration, two-dimensional gel electrophoresis and SDS gradient gel electrophoresis. The N-terminal residual sequence of a 26 kD glycoprotein was analyzed. Plant-wilting tests were carried out by injection of glycoproteins, and those treated by heat, ConA and zeatin, into cotton leaves, respectively. Results showed that heat and ConA treatment abolished the wilt-causing activity of the glycoproteins, and zeatin alleviated the wilt syndrome of cotton. Furthermore, the glycoproteins were found to be effective elicitors in inducing the biosynthesis of sesquiterpene aldehyde phytoalexins in suspension cell cultures of Gossypium barbadense L., and heat-treatment lowered, but not abolished the elicitor activity. However, application of native glycoproteins at the concentration higher than 5 mg/L resulted in cell death.
Abstract (Browse 1692)  |  Full Text PDF       
Purification and Identification of Antifreeze Proteins in Ammopiptanthus mongolicus
Author: JIANG Yong, WEI Ling-Bo, FEI Yun-Biao, SHU Nian-Hong and GAO Su-Qin
Journal of Integrative Plant Biology 1999 41(9)
      
    The conventional protein chromatography technique was adopted to purify the antifreeze proteins (AFPs) from the leaves of Ammopiptanthus mongolicus ( Maxim. ) Cheng f. Two bands on native PAGE gel showed thermal hysteresis activity, one was band Bi, whose thermal hysteresis was 0.46 cE at 8 g/L, which showed two bands (67 kD, 21 kD) on SDS-PAGE gel; the other was B3, whose thermal hysteresis was 0.45 cE at 10 g/L, and it contained only a single protein (39.8 kD). Both B1 and B3 are not glycoproteins, because neither do they interact with Shift-reagent, nor show ultraviolet characteristics of a typical glycoprotein.
Abstract (Browse 1844)  |  Full Text PDF       
Influence of K£« on the Coupling Between ATP Hydrolysis and Proton Transport by the Plasma Membrane H£«-ATPase from Soybean Hypocotyls
Author: QIU Quan-Sheng
Journal of Integrative Plant Biology 1999 41(9)
      
    The plasma membrane vesicles were purified from soybean ( Glycine max L. ) hypocotyls by two-phase partitioning methods. The stimulatory effects of K+ on the coupling between ATP hydrolysis and proton transport by the plasma membrane H+-ATPase were studied. The results showed that the proton transport activity was increased by 850% in the presence of 100 mmol/L KC1, while ATP hydrolytic activity was only increased by 28.2%. Kinetic studies showed that Km of ATP hydrolysis decreased from 1.14 to 0.7 mmol/L, while Vmax of ATP hydrolysis increased from 285.7 to 344.8 nmol Pi¡¤mg- l protein¡¤min-1 in the presence of KC1. Experiments showed that the optimum pH was 6.5 and 6.0 in the presence and absence of KC1, respectively. Further studies revealed that K+ could promote the inhibitory effects of hydroxylamines and vanadates on the ATP hydrolytic activity. The above results suggested that K+ could regulate the coupling between ATP hydrolysis and proton transport of the plasma membrane H+ -ATPase through modulating the structure and function of the kinase and phosphatase domains of the plasma membrane H + -ATPase.
Abstract (Browse 1651)  |  Full Text PDF       
RAPD Linkage Mapping in a Populus adenopoda¡ÁP. alba F1 Family
Author: YIN Tong-Ming, HUANG Min-Ren, WANG Ming-Xiu, ZHU Li-Huang, HE Ping and ZHAI Wen-Xue
Journal of Integrative Plant Biology 1999 41(9)
      
    Random amplified polymorphic DNAs(RAPDs) were used to construct linkage maps of the parents of a Populus adenopoda Maxim. x P. alba L. Fl family. A set of 620 random oligonucleotide primers were screened and 128 primers were selected to generate RAPD markers within a sample of 80 Fl progenies. A total of 333 segregating loci [ (326( 1:1 ) ,7(3:1 ) ] were identified. Among the 326 1:1 segregating loci (238 loci from P. adenopoda and 88 loci from P. dba),36 loci (26 loci in P. adenopoda and 10 loci in P. dba) were found distorted from the normal 1:1 ratio. Altogether 290 loci segregating 1:1 (testcross configuration) were used to construct parent-specific linkage maps,212 for P. alba and 78 for P. adenopoda. The resulting linkage maps consisted of 189 marker loci in 20 groups (four or more loci per group), 6 triples and 16 pairs for P. dba, which cover the map distance about 2 402.4 cM, and 41 linked marker loci for P. adenopoda which cover map distance about 479.4 cM. Further study is warranted to locate some important quantitative trait loci (QTLs) based on the maps.
Abstract (Browse 1894)  |  Full Text PDF       
Identification of a RAPD Marker Linked to Fusarium Wilt Resistant Gene in Wild Watermelon Germplasm (Citrullus lanatus var. citroides
Author: XU Yong, OUYANG Xin-Xing, ZHANG Hai-Ying, KANG Guo-Bin, WANG Yong-Jian and CHEN Hang
Journal of Integrative Plant Biology 1999 41(9)
      
    Random amplified polymorphic DNA(RAPD) was employed to detect a molecular marker linked to Fusarium wilt resistant gene in the wild watermelon ( Citrullus lanatus (Thunb.) Mansfeld var. citroides ) germplasm P1296341. The resistance to race 1 Fusarium wilt of PI296341 was controlled by one dominant gene. A RAPD marker OPPO1/700 was proved to be linked to the resistant gene. The genetic distance is 3.0 cM (centimorgan). This work has provided a solid basis for molecular marker-assisted selection (MAS) for disease resistance, and made location and cloning of disease resistant genes possible.
Abstract (Browse 1847)  |  Full Text PDF       
Studies on Insect Resistance of Bt Transplastomic Plants and the Phenotype of Their Progenies
Author: ZHANG Zhong-Lin, CHEN Xi, QIAN Kai-Xian and SHEN Gui-Fang
Journal of Integrative Plant Biology 1999 41(9)
      
    Insecticidal protein gene CrylA (c) from Bacillus thuringiensis (Bt toxin gene) was placed under the control of psbA5'- and 3'- regulatory regions of rice (Oryza sativa L. ) chloroplast to construct Bt expression cassette, which was ligated with selectable marker aadA cassette and homology regions of tobacco ( Nicotiana tabacum L. ) chloroplast genome to generate transformation vector pTRS8. Leaves of tobacco plant cv. NC89 were transformed with particle bombardment method, plastid transformants were selected by their resistance to 500 mg/L of spectinomycin. Some transplastomic plants were toxic to the third-instar larvae of Helicoverpa zea, and the growth of the survived insects was remarkably inhibited. Genetic and molecular analyses of T1 and T2 progenies of plants with highly efficient insect resistance showed that Bt toxin gene had been inherited in progenies, and spectinomycin resistance was inherited maternally.
Abstract (Browse 1778)  |  Full Text PDF       
Precise Identification of the Introgressed Segments in Powdery Mildew-resistant Introgression Lines of Triticum aestivum-T.timopheevi
Author: TAO Wen-Jing, LIU Jin-Yuan, LIU Da-Jun and CHEN Pei-Du
Journal of Integrative Plant Biology 1999 41(9)
      
    On the basis of the reported location of the Pm6 gene, 36 homoeologous group-2 specific probes were selected to detect polymorphism between wheat/Triticum timopheevi Zhuk. Pm6 introgression lines and their recurrent parent "Prins". Two Pm6 introgression lines IGV1-456, IGV1-458 were distinguished from the others. Nineteen long ann specific and six short ann specific probes detected the RFLPs between resistant IGV1456, IGV1-458 and susceptible control "Prins", indicated that the introgressed T. timopheevi 2G chromatin involve beth arms spanning across the centromere between markers Xcdo405 and Xbcd135. Only 6 of the nineteen long ann specific probes and two additional probes£­BCD292, CDO678 showed RFLPs between chromosome 2B of "Prins" and IGV1-463. This means that the introgressed T. timopheevi segment in IGV1- 463 with breakpoints between markers Xbcd307 and Xcdo678 is smaller than those detected in IGV1-456 and IGV1-458. Two of the six long arm specific probes PSR934, BCD135 detected polymorphism between IGV1- 464 and "Pr ins", and only one clone BCD135 revealed RFLPs between IGV1-465 and "Pr ins", which indicated that the introgressed segments in these two lines are smaller than those in others. As the introgressed segments in all the introgression lines bear the Pm6 gene, after comparison of the overlaps of the introgressed segments, it might be reasonable to map the gene Pm6 in the region of marker Xbcd135-2BL flanked 2BL.
Abstract (Browse 1729)  |  Full Text PDF       
Study on Optimization of Transformation of Populus tomentosa
Author: HAO Gui-Xia, ZHU Zhen and ZHU Zhi-Ti
Journal of Integrative Plant Biology 1999 41(9)
      
    Several factors affecting transformation of Populus tomentosa Carr. were studied, and a simple and effective protocol with optimized condition for transformation of P. tomentosa was developed. The results demonstrated that the transformation frequency was extremely increased with the presence of acetosyringone, and likely with the Agrobacterium tumefaciens (Smith et Townsend) Conn density, duration of infection and co-cultivation. It was found that removal of CoCl2¡¤6H20 from the co-culture medium was benefitial to obtain Kanr shoots.
Abstract (Browse 1623)  |  Full Text PDF       
Molecular Characterization of a Chinese Soybean Mosaic Virus Isolate by RT-PCR, cDNA Sequence Analysis and Direct Expression of PCR Products in Bacteria
Author: ZHANG Jing-Feng, ZHAO Hui, GUI Jin-Gang, LIU Kun-Fan and WANG Dao-Wen
Journal of Integrative Plant Biology 1999 41(9)
      
    Soybean mosaic virus (SMV) causes one of the most severe viral diseases in soybean ( Glycine max L. ) and is known to contain many pathogenically and serologically related isolates. In the present study, the authors have obtained cDNAs to all cistrons of a Chinese SMV isolate, SMV-ZK, by RT-PCR. By analyzing the nucleotide and amino acid sequence of the HC-PRO, Nib and CP cistrons, it was found that SMV-ZK was highly homologous to the G2 strain of SMV, thus confirming the existence of G2-1ike isolates in soybean crop in China. The amplified cDNAs were directly cloned into a bacterial expression vector. With the exception of the P3 cistron, expression of the cDNAs of all other cistrons in bacteria gave rise to polypeptides of expected molecular weight. The expressed viral proteins were subsequently purified by gel elution. The preparation of viral-specific cDNAs and gene products will be useful in future functional study of the SMV genome.
Abstract (Browse 1727)  |  Full Text PDF       
Screening,Identification and Distribution of Endophytic Associative Diazotrophs Isolated from Rice Plants
Author: YANG Hai-Lian, SUN Xiao-Lu, SONG Wei, WANG Yun-Shan and CAI Miao-Ying
Journal of Integrative Plant Biology 1999 41(9)
      
    29 strains of endophyte associated diazotrophs isolated from rice ( Oryza sutiva L. ) "Yuefu" plant were selected by in vitro acetylene reduced activity and 15 N2-flxing activity determination. They were identificated into 14 species of 9 genera: Agrobacterium tumefaciens (Smith et Townsend) Conn, A. radiobacter (Beijerinck et van Delden) Conn; Alcaligenes piechaudii Kiredjian et al., Al. denitrificans (Leifson et Hagh) Ruger et Tan; Bacillus sphaericus Meyer et Neide, B. licheniforrnis Weigmann Chester, B. cereus Frankland et Frankland; Chryseomonas luteola (Kodama, Kinnura et Komagata) Holmes et al.; Enterobacter cloacae ( Jordan ) Honnaeche et Edwards, E. sakazakii Famer et al.; E. agglomeraus (Beijerinck) Ewing et Fife; Pseudomonas pseudoalcaligenes Stanier, P. alcaligeaes Monias, P. putida Biotype A Evans and Aeromonas Kluyver et van Niel, Serratia Bizio, Staphyloccocus Rosenbach, Xanthomonas Dowson. Among them C. luteola, E. sakazakii, E. agglomeraus, P. pseudoalcaligenes have not been previously reported as diazotrophs. Studying on the distribution of endophytic dizoatrophs in rice seeds and rice plants has demonstrated that the diversity of endophytic associated diazotrophs in roots was more than that in other organs of rice plant. Endophytic associative diazotroph E. cloacae not only occurred on the surface but also occurred intercellularly in R48 rice roots as observed with scanning electron microscopy and transmission microscopy.
Abstract (Browse 2421)  |  Full Text PDF       
Induction of Continuous Tepal Differentiation from in Vitro Regenerated Flower Buds of Hyacinthus orientalis
Author: LU Wen-liang, BAI Shu-Nong and Zhang Xian-Sheng
Journal of Integrative Plant Biology 1999 41(9)
      
    Continuous differentiation of tepals was successively induced from regenerated flower buds in Hyacinthus orientalis L. cv. White Pearl by controlling the exogenous hormones and explant ages. In 250 days of subculture, each flower bud differentiated an average of more than 70 tepals, with a maximum of over 140 tepals. Studies on the morphogenesis and characteristics of growth and development of the flower buds indicate that the first whorled organ of the flower bud was perianth which consisted of perianth tube and tepals grown at the top of the perianth tube, which is the same as the flower bud of the wild type in H. orentalis. The second and third whorls of the flower bud, which should be stamen and pistil in the wild type, but remained as the tepals in the regenerated flower bud. Growth of the regenerated flower bud was faster in the first several months of culture, then slowed down gradually with time. After 150 days in culture the flower bud growth and organ differentiation became very slow. Other than the tepal differentiation the regenerated flower buds also differentiated at random positions some small flower buds that also differentiated the tepals only. Histological observation revealed that the origin of the regenerated flower buds was jointly participated by some cells in the epidermal and subepidermal layers at the inner surface of the perianth explant, and the inner small flower buds were originated from the meristem which was formed by the transformation of the parenchyma at the base of the very young tepal. The authors also compared and discussed the similarities and differences of the phenotypes between the regenerated flower bud in Hyacinthus and agamous flower in Arabidopsis, from which, they have hypothesized on the role of the hormones in the promotion and termination of the gene expressions by an order of development in plant.
Abstract (Browse 1755)  |  Full Text PDF       
Plant Development and Reproduction: Advances and Prospectives
Author: XU Zhi-Hong
Journal of Integrative Plant Biology 1999 41(9)
      
    Plant development and reproduction research has been moving very rapidly in the past 10 years due to the progress of molecular biology, the analysis of various developmental mutants, and the cloning of the genes with important function in different stages of plant development. This review focuses on apical mefistem, flower initiation and development, fertilization and embryogenesis. Recent advances and the prospects in the future are discussed.
Abstract (Browse 1711)  |  Full Text PDF       
 

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