December 1995, Volume 37 Issue 12

 

          Research Articles
Westphalian Sporo-Pollen Assemblages from the Upper Carboniferous in Zhongwei, Ningxia
Author: Wang Yong-dong
Journal of Integrative Plant Biology 1995 37(12)
      
    About 98 species of fossil spores and pollen referred to 55 genera from the Upper Carboniferous Yanghugou Formation in Zhongwei, Ningxia have been studied. Two sporopollen assemblage zones are recognized in ascending order as follows: 1. Laevigatosporites medius-Cyclogranisporites aureus (MA) zone: This assemblage corresponds to the lower part of the Yanghugou Formation, and is characterized by the predominance of pteridophyfic spores and the relative abundance of gymnospermous pollen. Azonotriletes and monoletes are dominant, while zonates are of importance. The most common species are Leiotriletes spp., Cyclogranisporites aureus Potoni6 et Kremp, Granulatisporites granulatus Ibrahim, Microreticulatisporites concavus Butterworth et Williams, M. nobilis (Welcher) Knox, Triquitrites bransonii Wilson et Hoffmeister, Dictyotriletes bireticulatus (Ibrahim) Smith et Butterworth, Ahrensisporites guerickei (Horst) Potonie et Kremp, Lycospora spp., Crassispora kosankei (Potonie et Kremp) Bharadwaj, Cirratriradites saturni (Ibrahim) Schopf, Wilson et Bentall, Laevigatosporites spp., Columinisporites ovalis Peppers, Florinites junior Potnie et Kremp and Vesicaspora wilsonii (Schemel) Wilson et Venkatachata. This assemblage is comparable with those of the Yanghugou Formation in Baiyantaohai of Inner Mongolia (Yu, 1983), the 8th zone of North China by Gao (1979), the Triquitrites sinani-Cirratriradites saturni (SS) Zone and the Microreticulatisporites nobilis-Florinites junior (NJ) Zone of West Europe, which are considered corresponding to Westphatian A-B in age. 2. Torispora seuris-Punctatisporites hians (SH) zone: This assemblage is equivalent to the upper part of the Yanghugou Formation, and is also characterized by dominance of pteridophytic spores and subdominance of gymospermous pollen. In addition to the most commen species mentioned above, the important taxas in the present assemblage comprise Punctatisporites hians Wang, Gulisporites cochlearius Imgrund, Verrucosisporites kaipingiensis Imgrund, Endosporites globiformis (Ibrahim) Schopf, Wilson et Bentall, Densosporites anulatus (Loose) Smith et Butterworth, D. reticuloides Ouyang et Li, Simozonotriletes labellatus Wang, Torispora securis Balme, Thymospora thiessenii (Kosanke) Wilson et Venkatachala, Pit yos porites west phalensis Williams and Plat ysaccus, Illinites, C ycadopites, etc. This zone compares closely with those of the upper part of the Yanghugou Formation in Hengshanbu (Wang Hui, 1984) and Ordos Basin (Geng, 1985), the Benxi Formation in Shanxi (Liao, 1987; Ouyang and Li, 1980; Gao, 1979), as welll as Torispora securis-T, laevigata (SL) Zone and Thymospora obscura-T, thiessenii (OT) Zone of West Europe. Therefore, the present SH Zone should be referred to Westphalian C-D in age. The Westphalian palynofiora in Zhongwei is dominated by Filicopsida and pteridospermopsida; Sphenopsida and lycopsida occupy the subdominant position, while Cordaitopsida and Coniferopsida do not develop well. This palynofiora indicates a tropical-subtropical warm and humid paleoclimate.
Abstract (Browse 1907)  |  Full Text PDF       
Study on the Dynamics and Rhythms of Midmontane Wet Evergreen Broad-Leaved Forest at Xujiaba, Ailao Mountains, Yunnan
Author: Wu Bang-xing
Journal of Integrative Plant Biology 1995 37(12)
      
    According to data of long-term observation, the dynamics and the rhythms of the wet evergreen broad-leaved forest in respect of seed germination, seedling growth, growth laws, and phenological rhythms of the mature trees of constituent species were analyzed. The species numbers of the seeds, germinable seeds and germinated seeds of the forest in rainy season were larger than those in dry season. The growth rate of the seedlings was faster in rainy season as well indicating a season most favourable for the growth of seedlings. The growth of trees was a process of inter-specific competition, self-regulation and self-thinning. The long and indistinctive phenologieal phases of the mature trees differed from those short and distinctive phenological phases of the broad-leaved forests in the temperate. Its continuous flowering, fruiting and fruit-falling were similar to the phenological rhythms of seasonal rain forests in Xishuangbanna. However, leaf-shedding of the seasonal rain forests in Xishuangbanna, the evergreen broad-leaved forests and the temperate broad-leaved forests was in spring (February March), in Winter (November December) and in autumn (SeptemberOctober) respectively. Based on the characteristics in the phenological rhythms of the species and their responses to the climates, the three eeo-phenological types were divided as: 1. The warm temperate eeo-phenological type, whieh accounts for 82 % of the total species number (50); 2. The temperate ecophenological type, 12%; 3. The cool temperate eco-phenological type, 0. 6 %.
Abstract (Browse 1820)  |  Full Text PDF       
Embryological Studies on Convallaria majalis L.
Author: Rao Guang-yuan, Pan Kai-yu and Hong De-yuan
Journal of Integrative Plant Biology 1995 37(12)
      
    Embryological studies on Convallaria majalis L. revealed that: 1. The anther was four sporangiate. The development of anther walls conformed to the monocotyledonous type. The tapetum, of which each cell contained two or many nuclei in the later stages, was of glandular type. Meiosis of the microspore mother cells was accompanied by successive cytokinesis, which resulted in the formation of isobilateral and tetrahedral tetrads. The mature pollen grains were of the 2-celled type. 2. The ovary was trilocular. The placentation was axile, but placentas were not fully fused in the center of the ovary. The ovule was bitegminous, crassinucellate and anatropous. The micropyle was formed by the inner integument. 3. The development of the embryo sac was of the Allium type and Endymion type. 4. Raphides were observed in the ovary wall, the funiculus and the outer integument after fertilization. 5. The development of the embryo was similar to the Caryophyllad type, but the basal cell was vertically divided into two cells. 6. The development of the endosperm was of the nuclear type. However, the gigantic endosperm nucleus was formed at the chalazal end.
Abstract (Browse 1832)  |  Full Text PDF       
Water Relations of Tomato Seeds During Imbibition and Osmotic Priming
Author: Liu Yong-qing, Luo Ze-min, Hilhorst H W M and Karssen C M
Journal of Integrative Plant Biology 1995 37(12)
      
    Water uptake of tomato (Lycopersicon esculentum Mill. cv. Moneymaker) seeds during germination was obviously triphasic. The completion of the first phase of water uptake by whole seed could not be realized until 1012 h later after sowing though varies in different parts of seed. The mechanical resistance of endosperm and seed coat restricted water uptake of the embryo envoleped by the endosperm. Water potential of the intact embryo was still 0. 60. 9 Mpa lower than the whole seed when the equilibrium between seed and imbibing solution was established. GA and ABA had no direct effects on the water uptake of tomato seeds. The water potential of embryo was positively correlated with its moisture content. The osmotic potential of tomato embryos decreased slowly during imbibition in water and osmotic solution as well.
Abstract (Browse 2031)  |  Full Text PDF       
Effects of Water Stress on Chlorophyll-Protein Complexes in Wheat Chloroplasts
Author: Lu Cong-ming, Tang Chong-qin, Zhang Qi-de and Kuang Ting-yun
Journal of Integrative Plant Biology 1995 37(12)
      
    The excitation energy transfer from light harvesting chlorophyll protein complexes to PS was inhibited under water stress. The contents of iriternal antennae chlorophyll-protein complexes of PS (CPa), light harvesting chlorophyll-protein complexes of PS (LHC ), light harvesting chlorophyll-protein of PS (LHC ) and chlorophyll a protein complex of reaction center of PS were decreased by water stress. The decrease of chlorophyll-protein complexes of PS was greater than that of PS . It was indicated that the amount of 25 kD polypeptide of LHC in particular, as well as that of 43 and 47 kD polypeptides of CPa, and 21 kD polypeptide of LHC , were reduced by water stress.
Abstract (Browse 1771)  |  Full Text PDF       
Subcellular Localization and Kinetic Characterization of ABA Binding Proteins in Maize Root
Author: Zhu Mei-jun and Chen Jia
Journal of Integrative Plant Biology 1995 37(12)
      
    By means of differential centrifugation, cytosol fraction and microsome were prepared from maize roots which have been grown in dark for 4 d. Highly purified plasma membranes were isolated from the microsome in two-phase aqueous system which is composed of 6.9 % (W/W) Dextran T500 and PEG 3350. The tonoplast was collected from the interface between 1% and 8% (W/W) Dextran T70 after gradient centrifugation. Electron microscopic observation and marker enzyme activities analysis proved that these fractions contained very few other membranes. Microvolume radioactivity ligand binding assay indicated that the specific binding sites of ABA in maize root microsome were mainly distributed on tonoplast and plasma membrane fractions. Their specific binding activity was 2485.4 and 1257.3 fmol/mg protein, respectively, the specific binding activity of cytosol fraction being the lowest (one order of magnitude lower). The dissociation constant (KD) of ABA-BP in plasma membrane was 1.57 nmol/L.
Abstract (Browse 1800)  |  Full Text PDF       
Structural Requirement for Clusters to be Reconstituted with the FeMoCo-Deficient Molybdenum-Iron Protein
Author: Huang Ju-fu, Luo Ai-ling, Li Jia-ge, Xu Ji-qing, Nan Yu-ming and Chen Ya-dong
Journal of Integrative Plant Biology 1995 37(12)
      
    By incubating the reduced MoFe protein from Azotobacter vinelandii with O-phenanthroline under air and chromatographying the incubated solution on Sephadex G-25 column, inactive MoFe protein could be obtained. Its acetylene-reduction activity was remarkably recovered not only by incubation with the reconstituent solution composed of KMnO4, ferric homoeitrate, Na2S and dithiothreitol, but also with a mixture of 4Fe : 4S clusters and another cluster which had two structure units of 1Mo : 3Fe : 4S-bridged by three -OCH3 at the Mo atoms. Neither the reconstituent solution nor the mixture could reactivate apo-MoFe proteins from the mutants deleting nile and nifH genes and from the mutant UW45, which could be reactivated by the FeMoeo extracted from the MoFe protein. The results indicated that the FeMoeo-defieient MoFe proteins from these mutants seemed to be reconstituted only by the clusters which were probably structures only similar to FeMoeo. The partially metalloeluster-deficient MoFe protein could be reconstituted by the clusters with a certain kind of structure and composition; and was changed into different nitrogenase proteins with the ability to fix nitrogen.
Abstract (Browse 1812)  |  Full Text PDF       
Studies on Nitrate Reductase in Plasma Membrane of Maize Roots
Author: Hong Jian ming, Huang Qing ni, Qiu Ze sheng, Liu Xiang lin, Yin Li ping and Chai Xiao qing
Journal of Integrative Plant Biology 1995 37(12)
      
    Nitrate reductase (NR) activity was identified in the right-side-out and inside-out of high purity plasma membrane (PM) vesicles in maize (Zea mays L. ) roots which was obtained by aqueous two-phase partitioning. The inducement property of the NR activity in PM could be confirmed through culturing the meterial with or without nitrate component. Analysis from experimentation with external electron donor indicated that the maize root NR in PM could utilize not only NADH but also NADPH directly or indirectly as its electron donor. Treatment with Triton X-100 combining with trypsin and inhibitor demonstrated that NR protein was a trans-PM protein mainly facing the apoplastic side, being specially sensitive to trypsin. The possible function of the NR in PM is also discussed.
Abstract (Browse 1853)  |  Full Text PDF       
cDNA Cloning and Structural Analysis of Rice ADP-Glucose Pyrophosphorylase Gene
Author: Qu Li-jia, Ji Mei, Lan Ning, Xie Ming, Gu Hong-ya and Chen Zhang-liang
Journal of Integrative Plant Biology 1995 37(12)
      
    ADP-glucose pyrophosphorylase is a key enzyme in the pathway of starch synthesis. The gene encoding this.important enzyme was cloned by PCR amplification from immature seeds of a Chinese rice cultivar-Oryza sativa var. japonica cv. Zhonghua 10. It was then sequenced and compared with the same gene reported from other rice cultivar. The gene obtained in this study is composed of 1461 bp and encodes 483 amino acid residues. Its nucleotide sequence and deduced amino acid sequence shared 99.6% and 99.7% homology with those of published data respectively. The analyses on the structure and evolution of this gene have been conducted.
Abstract (Browse 1975)  |  Full Text PDF       
Origin of Megagametophytes with Supernumerary Egg Cells Occurring in Oryza sativa
Author: Liu Yong-sheng, Sun Jing-san, Liu Tai-qing, Pan Sheng-fa and Li Xian-yong
Journal of Integrative Plant Biology 1995 37(12)
      
    Cytoembryological observations were attempted to reveal the cytological origin of megagametophyte with supernumerary egg cells. It was shown that all ovules underwent a normal megasporogenesis. The meiosis of megasporocyte consisted of two successive divisions, which gave rise to four haploid megaspores. It was the chalazal spore that developed to form the megagametophyte while the three micropylar megaspores degenerated quickly. After first mitosis in the functional megaspore the two nuclei were separated to the micropylar and chalazal poles by a large central vacuole, meanwhile a differential enlargement of the two-nucleate embryo sac was visualized. The micropylar side enlarged quickly and in contrast, the chalazal side remains almost unchanged. Immediately afterward, the second mitosis took place forming four-nucleate embryo sac. During the second mitosis, nucleus located in the narrow area of chalazal side divided transversely, with its upper sister nucleus migrating to the central or micropylar part of the embryo sac, while the nucleus in the micropylar side divided at an angle of about 45 against the micropylar-chalazal axis. Through the third mitosis, two patterns of nuclear arrangement deviating from polygonum were observed. (i) One nuclear distribution pattern was two, two, four respectively in chalazal, central and micropylar parts. And during maturation the four micropylar nuclei differentiated as egg apparatus consisting of two egg cells and two synergids. The two central nuclei, which presumably suppressed the movement of nucleus toward centre part from both micropylar and chalazal sides developed into central cell with two polar nuclei. And the two chalazal nuclei organized into antipodal cells. Rarely indeed, one nucleus of either chalazal or micropyle side did migrate to join the formation of central cell. (ii) The other nuclei arrangement pattern was two and six respectively positioned in chalazal and micropylar sides. During maturation, five micropylar nuclei differentiated into egg apparatus consisted of three egg cells and two synergids. The sixth one migrated to form the upper polar nucleus. The lower nucleus of the chalazal side developed into antipodal cell which divided quickly, and the upper nucleus became the lower polar nucleus.
Abstract (Browse 1949)  |  Full Text PDF       
 

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