August 1999, Volume 41 Issue 8

 

          Research Articles
The First Record of Dynamics of Male-Female Nuclear Fusion in Viable Tobacco Central Cell During in Vitro Fertilization
Author: SUN Meng-Xiang, Alessandra MOSCATELLI, YANG Hong-Yuan and Mauro CRESTI
Journal of Integrative Plant Biology 1999 41(8)
      
    In vitro double fertilization in tobacco (Nicotiana tabacum L. ) was carried out and one of its significant events, the dynamics of bisexual nuclear fusion in the viable central cell, was observed by video- enhanced microscopy for the first time. The observation revealed that after in vitro fertilization the male nucleus was first fused with one of the polar nuclei, then the other. The whole fusion process could be finished within two seconds. Morphologically the fusion was very similar to common protoplast fusion mediated by polyethylene glycol. It also went through a series of processes, namely touch, adherence, membrane fusion and content mixture. The male nucleolus moved closely towards the female one but no further fusion was recorded although eventually a big nucleolus was observed in the primary endosperm nucleus. The technique for in vitro fertilization and the observation of the nuclear fusion process may enable us to peep at the mechanism of male and female gamete fusion.
Abstract (Browse 1662)  |  Full Text PDF       
Comparison of Polypeptide Synthesis in Leaf of Panicum repens Grown in Different Habitats
Author: WANG Wei, CHEN Liang and CUI Hong
Journal of Integrative Plant Biology 1999 41(8)
      
    he polypeptide synthesis in leaf of Panicum repens L. grown naturally in different habitats was analyzed using SDS-PAGE. Preliminary experiment indicates that the overall changes in polypeptide synthesis were relatively small, but the synthesis of a 30.6 kD polypeptide was enhanced in P. repens grown in sandy beach (salinity 1.5% 3.0 % ) and that of a 130 kD pelypeptide markedly decreased. However, the content of the 130 kD protein increased in P. repens grown in sandy farmlands (salinity 0.1%0.3% ), especially in water marsh (salinity 0.3 % 0.5 % ).
Abstract (Browse 1632)  |  Full Text PDF       
New High Resolution Pollen Records from Two Lakes in Xizang (Tibet)
Author: TANG Ling-Yu, SHEN Cai-Ming, LIU Kam-Biu and J. T. OVERPECKShort Communication
Journal of Integrative Plant Biology 1999 41(8)
      
    Studies on the pollen from cores of Lake Hidden (29~48.77' N, 92~22.37' E) and Ren Co (30%3.97'N, 96~40.97'E) in Southeast Xizang (Tibet) showed climatic changes and the evolution of vegetation since the last Glacial Maximum (LGM). Before 16 ka BP pollen assemblages were dominated by Chenopodiaceae (20% -50% ) and Artemidis (10% ~ 30% ) and pollen influx values were very low from Lake Ren Co in Basu county. The vegetation around the lake was probably a desert-steppe during the LGM. The data also suggest that the climate in the Basu area was cold and dry during the LGM and the last glacial time. The mean annual temperature was probably 4 ~ 6 colder than the present, and the mean annual precipitation was only 250 mm, about 40% of the present. The Southwest monsoon became stronger from 12 ka BP to 6 ka BP reaching its acme by 7 ka BP, but weakened gradually from 5 ka BP to the present. The paleovegetation was dominantly forest or forest-meadow around Lake Hidden and Ren Co during the 9.2 ~ 5 ka BP. The mean temperature in January was probably 2 ~ 3 higher than the present, and the mean annual precipitation was 100 mm more than the present. The timing of vegetational and climatic changes based on pollen records generally supports the results of global climatic-model experiments that predict a strengthened monsoon system during the early to middle Holocene followed by a weakened monsoon system.
Abstract (Browse 1756)  |  Full Text PDF       
The Community Dynamics of the Forest Secondary Succession in Heishiding Natural Reserve of Guangdong Province
Author: ZHOU Xian-Ye, WANG Bo-Sun, LI Ming-Guang and ZAN Qi-Jie
Journal of Integrative Plant Biology 1999 41(8)
      
    Studying on the community structure, species composition and species diversities of the secondary succession of lower subtropical forest in Heishiding Natural Reserve, Guangdong Province, the following results were obtained. In 2 ~4 years of restored stage the seedlings of pioneer species, heliophytes and mesophytes occur simultaneously. In 10 years of restored stage pioneer species are superior as heliophytes maintain stable and mesophytes are being decreased. In the stage of mixed forest pioneer species are on the decreasing and heliopytes are on the increasing trend. In the stage of evergreen broad-leaved forest dominated by heliophytes pioneer species are being declined, heliophytes are dominant and mesophytes are being increased. In the stage of evergTeen broad-leaved forest dominated by mesophytes heliophytes are being declined and mesophytes are superior. The vertical structure, horizontal structure, the structure of species composition determine stability of communities in secondary succession process. The vertical structure of community is building up in the stage of restoration. The community is composed of the stands under the third class. The forest canopy is not stratified. The individual density is stable. From restored stage to mixed forest the vertical structure of community is diversified. There are the third and forth class stands in community. The tree layer is divided into three sub-layers. The individual density declines rapidly because of self-thinning. In the mixed forest the vertical stmcture is relatively stable. The abundance of the fifth class stands and area of breast height reach the first peak in the succession serial. The individual density increases rapidly. In stage of evergreen broad-leaved forest dominated by heliophytes, the vertical structure changes largely. The abundance of the fifth class and area of breast height decline rapidly, but the individual density changes slowly. In the stage of evergreen broad-leaved forest dominated by mesophytes, the vertical structure of community is stable and the composition of every stand class becomes more stable. The area of breast height is the biggest in the succession serial. When succession develops, the coverage of communities increases gradually but the turnover rate of species declines. The species composition tends to be stabilized. The diversity of species and community evenness increase gradually thus, the ecological dominance declines gradually.
Abstract (Browse 2156)  |  Full Text PDF       
Architecture of Clonal Plants and Morphological Responses to Habitat Heterogeneity
Author: LI Zhen-Qing
Journal of Integrative Plant Biology 1999 41(8)
      
    The phalanx and querilla are two extreme architectures. There should be a continuum of interim architecture between phalanx and querilla. The author gives an index describing the continuum v=ln /Inn( v1), and discusses the response of spacer length to habitat patchy quality.
Abstract (Browse 1714)  |  Full Text PDF       
History of Disturbance and Regeneration Strategies of Fagus engleriana and Quercus aliena var. acuteserrata Forests in Shennongjia, Hubei Province
Author: HE Jin-Sheng, LIU Feng, CHEN Wei-Lie and CHEN Ling-Zhi
Journal of Integrative Plant Biology 1999 41(8)
      
    Based on plot investigation, stem analysis and radial growth pattern, the authors studied the history of suppression, release and regeneration strategies of Fagus engleriana Seem. and Quercus aliena var. acuteserrata Maxim. forests, which were widely distributed in Shennongjia of Hubei Province. It was found that (85.9 6.9) % of the Fagus engleriana samples showed periods of suppression during their canopy recruitment. The average number of suppression periods was 2.1 0.8, the average total length of suppression time was (47 24.1) a, the length of longest suppression time was 73 a, the average number of periods of release was 1.60.7, and the average total length of release time was 23 a. (60.8317.3)% of the Quercus aliena var. acuteserrata samples showed periods of suppression but without release. Combined with height and radial growth characteristics, these suggest that Fagus engleriana was shade-tolerant species, and its regeneration strategies was release from seedling sprouts in canopy gaps, while Quercus aliena var. acuteserrata was shade-intolerant species, and its regeneration strategies was seedling establishment and growth in large canopy gaps by producing large amount of seeds.
Abstract (Browse 1729)  |  Full Text PDF       
Membrane Injury and PS Inactivation in Some Subtropical Woody Plants Induced by Photooxidation
Author: LIN Zhi-Fang, PENG Chang-Lian and LIN Gui-Zhu
Journal of Integrative Plant Biology 1999 41(8)
      
    Leaf discs from the pot-cultured seedlings of tree species and understory shrub species in a natural subtropical forest were treated with methyl viologen (MV) solution under low light or high light illumination. The degradation of chlorophyll and the leakage rate of electrolytes through membrane were enhanced by the increasing MV concentration and prolonged time of treatment. Membrane injury was more serious than oxidative bleaching of chlorophyll under the same condition. When leaf discs were subjected to short term (1 h) exposure of MV-photooxidation in high light (1 300 molm-2s-1), a pronounced decrease of Fv/Fm, PS and qp, as well as A505, A320 and ratio of qp/qN were observed in all tested species, which were accompanied by the increase of qN, KD and Fo. It demonstrated that photooxidation led to PS inactivation expressing in the reduction of the number of PS centre undergoing a stable charge separation and efficiency of the primary photochemical efficiency and noncyclic electron transport of PS . Partial excitation energy might dissipate via the useful nonphotochemical fluorescence quenching, but the lowering of A505 was not consistent with the elevation of qN. Understory shrub Psychotria rubra Poir., Ardisia quinquegona BI. Showed more susceptibility to photooxidation than the upper canopy tree species Schima superba Gardn. et Champ., Castanopsis fissa (Champ.) ex Benth. ) Rend. et Wils. and Syzygium rehderianum Merr. et Perry.
Abstract (Browse 1653)  |  Full Text PDF       
Effect of Different Light Quality on Photosynthetic Characteristics of Cucumber Leaves
Author: CHU Zhong-Xi, TONG Zhe, FENG Li-Jie, ZHANG Qun, WEN Xiao-Gang, SONG Sen-Tian and ZHU Xiao-Feng
Journal of Integrative Plant Biology 1999 41(8)
      
    Cucumber (Cucumis sativus L. cultivar "Changchun Mici") seedlings were cultured in Hoagland solution under irradiation with different light spectra (8 h per day) for 20 days. The red light (max 658 nm, 1/2 25 nm), blue light (max 450 nm, 1/2 43 nm) and white fluorescent light possessed the same fluent rate (20 mol m-2s-1 ). The experimental results showed that chlorophyll content of the leaves grown under white light was 7 % and 22.4% higher than those in red and blue light, respectively. Compared with white and blue light, red light induced a lower Chl a/b ratio and a higher level of Chl b in the cucumber leaves. Measurements of the low temperature (77 K) fluorescence emission spectra and kinetics of Chl a fluorescence induction of the leaves proved that the leaves grown under red light expressed the highest PS and the lowest PSactivities while the leaves under blue light had the lowest PSand the highest PS activities. The O2 evolution rate of red light-grown leaves was 44.9% higher than that of the white light-grown leaves, while blue light effect was similar to that of white in respect of O2 evolution. It is concluded that light quality is an important factor in regulating the development and activities of PS and PSand the O2 evolution of photosynthesis in cucumber leaves.
Abstract (Browse 1806)  |  Full Text PDF       
Effects of Strong Light and Active Oxygen on Photosynthesis in Soybean
Author: XUE Zhi-Fang, LUO Guang-Hua, WANG Ai-Guo, CHEN Yi-Zhu and GUO Jun-Yan
Journal of Integrative Plant Biology 1999 41(8)
      
    With the use of chlorophyll fluorescence technique, it was found that the net photosynthetic oxygen evolution rate decreased after strong light (2 000 mol m-22-1 ) treatment for two hours in soybean ( Glycine max L. ) leaves. The chlorophyll fluorescence parameters, Fm/Fo, Fv/Fm, PSII, qp and qN decreased along with the increase of light intensity. In strong light, exogenous active oxygen H202OH and 'O2 were harmful to soybean leaves. The destruction of 'O2 andOH to leaves was most evident, as was shown that Fv/Fm and PS H decreased significantly. The antioxidants DABCO, mannitol, ascorbate and histidine protected the leaves, but weakly, from strong light. In darkness, the SOD inhibitor sodium diethyldithiocar- bamate (DDC) had no significant effect on Fm/Fo and Fv/Fm, but NAN,, the ascorbate peroxidase (APX)inhibitor, significantly decreased Fm/Fo, Fv/Fm and PS II. In strong light, however, beth DDC and NaN3 reduced the above-mentioned fluorescence parameters, but NaN3 was more effective than DDC. The results suggested that photoinhibition did take place in soybean leaves under strong light, and it was related to active oxygen in vivo.
Abstract (Browse 1814)  |  Full Text PDF       
Effects of Periodical Soil Drying and Leaf Water Potential on the Sensitivity of Stomatal Response to Xylem ABA
Author: LIANG Jian-Sheng and ZHANG Jian-Hua
Journal of Integrative Plant Biology 1999 41(8)
      
    The study on the changes of stomatal sensitivity in relation to xylem ABA during periodical soil drying and the effect of leaf water status on the stomatal sensitivity has confirmed that xylem ABA concentration is a good indicator of soil water status around roots and the relation between xylem ABA concentration and predawn leaf water potential remained constant during the three consecutive soil drying cycles based on the slopes of the fitted lines. The sensitivity of stomata to xylem ABA increased substantially as the soil drying cycles progressed, and the xylem ABA concentration needed to cause a 50% decrease of stomatal conductance was as low as 550 mnoL/L in the next two soil drying cycle, as compared with the 750 nmol/L ABA in the first cycle of soil drying. The results using the split-root system showed that leaf water deficit significantly enhanced the stomatal response to xylem ABA and the xylem ABA concentration needed to cause a 50% decrease in stomatal conductance was 2 to 4 times smaller in the whole-root-drying treatment than those in the semi-root- drying treatment. These results suggested that the sensitivity of stomata to xylem ABA concentration is not a fixed characteristic.
Abstract (Browse 1720)  |  Full Text PDF       
Distribution of Rare Earth Elements and Structure Characterization of Chlorophyll-Lanthanum in a Natural Plant Fern Dicranopteris dichotoma
Author: HONG Fa-Shui, WEI Zheng-Gui, TAO Ye, WAN Shou-Kang, YANG Yue-Tao, CAO Xin-De and ZHAO Gui-Wen
Journal of Integrative Plant Biology 1999 41(8)
      
    The distribution pattern of La, Ce, Nd, Th, Dy was in the order as leaf > root > stem, that of Pr, Sm, Eu, Cd, Ho, Y was as root > leaf > stem in fern Dicranopteris dichotoma Underw. Light and moderately heavy rare earth elements were easily selectively absorbed and then accumulated by the fern D. dichotoma. Many mainly light rare earth elements are bound to chlorophyll in D. dichotoma. Among the 15 detectable rare earth elements binding to chlorophyll, lanthanum content (50.08 % ) was the highest, and cerium content (19.40%) is the second of all. FXAFS (Fluorescence X-ray absorption fine structure) spectral analysis revealed that lanthanum coordinated 2 porphyrin rings and La-chlorophyll-a may have bilayer structure in D.d/chotoma.
Abstract (Browse 1764)  |  Full Text PDF       
Effects of Altitude on Antioxidative System in Leaves and Roots of Plantago major
Author: CHEN Xiong, WANG Zong-Ling, REN Hong-Xu and ZHU Yuan-Lin
Journal of Integrative Plant Biology 1999 41(8)
      
    Antioxidative systems were investigated in leaves and roots of Plantago major L. which were collected from Mahan Mountain at different altitudes. The content of glutathione (GSH) in reduced form was increased in leaves and roots with the increasing altitude. The activities of peroxidase (POX) and superoxide dismatase superoxide dismutase (SOD) in roots also increased as the altitude was increased, while that in leaves they declined at higher altitude. Analyses of isozymes of SOD and POX in leaves and roots showed that high altitude (3 300 m) induced the SOD isozymes 8 and POX isozyme 5 in roots, which appeared to be required for protection against lower temperature and higher light intensity as altitude was increased. The present study suggested that high altitude had affected differently the antioxidative system in leaves and roots.
Abstract (Browse 1722)  |  Full Text PDF       
Isolation and Purification of ABA Binding Protein from Abaxial Epiderm of Vicia faba Leaf
Author: WU Zhong-Yi, ZHANG Da-Peng and JIA Wen-Suo
Journal of Integrative Plant Biology 1999 41(8)
      
    Abscisic acid (ABA) was efficiently cross-linked to Sepharose 4B (6 ~8 mmol ABA/L gel) by an ann of 10-atom carbon chain. Solubilized ABA-BP (ABA binding protein) was allowed to bind to the gel, while unrelated proteins were removed by washing with a gradient of NaC1 buffer. The ABA-BP was eluted with 1 mmol/L ABA. Since ABA at high concemration can interfere with both the binding activity assay and protein analysis, the fractions eluted with ABA were passed through a Sephadex G-25 column to remove the ABA. Fractions containing the binding activity were pooled, concentrated with uhm-fihration. The maximum binding capacity (BMAX) of the purified ABA-BP was 58.33 nmol/g protein, and the Kd was 21 nmol/L, with an approximately 112 folds increase of purity. SDS-PAGE identification of the purified ABA-BP revealed a major protein band with a molecular weight of about 44.2 kD, and a purity of approximately 90 %.
Abstract (Browse 1702)  |  Full Text PDF       
Biological Characterization of Heat-stable Antifreeze Proteins from Leaves of Ammopiptanthus mongolicus
Author: WEI Ling-Bo, JIANG Yong, SHU Nian-Hong, GAO Su-Qin and FEI Yun-Biao
Journal of Integrative Plant Biology 1999 41(8)
      
    Antifreeze protein(afp) was purified from the heat stable proteins in the leaves of Ammopiptanthus mongolicus (Maxim.) Cheng f. by two-dimensional electrophoresis-electrophoretic elution. Its molecular weight and pi are about 40 kD and 9.0 respectively, and its thermal hysteresis activity (THA) is 0.9 at 20 g/L. afp is different from other antifreeze proteins. The N-terminal 20 amino acids of afp is SDDLSFTFNKFVPCQTDILF. alp is abundant in leaves and may play an important role in the antifreeze process in A. mongolicus during the period of ovenwintering.
Abstract (Browse 1809)  |  Full Text PDF       
Effects of Enhanced UV- B Radiation on Protein Metabolism of Bean Leaves
Author: FENG Guo-Ning, An Li-Zhe, FENG Hu-Yuan and WANG Xun-Ling
Journal of Integrative Plant Biology 1999 41(8)
      
    Bean ( Phaseolus vulgaris L. ) seedlings were grown in a greenhouse condition under UV-B (280 ~ 320 nm) radiation and an UV-B-free control condition. At early stage of bean growth, UV-B radiation(UV- BBE: 16 kJm-2d-1 ) increased the synthetic rate of protein in bean leaves. UV-B radiation decreased the synthetic rate of protein and the content of soluble protein, increased the activities of caseolytic enzymes and the content of total amino acids in bean leaves at later growth stage. The results of SDS-PAGE indicated that UV-B radiation increased the contents of polypeptide in a range of 99 kD, 88 kD, 76 kD, 42 kD, 35 kD and 33 kD at the early stage, and increased that of 10 ~ 14 kD, 29 kD, 33 kD and 35 kD at later growth stage. It is suggested that the increase of these polypeptides is an adaptation response of plants to the enhanced UV-B radiation.
Abstract (Browse 1670)  |  Full Text PDF       
RAPD Analysis on High-taxane-contained Accessions of Taxus chinensis var. mairei
Author: HEN Yu-Heng, BAI Shou-Mei, CHENG Ke-Di, ZHANG Shu and LI Ji-Xue
Journal of Integrative Plant Biology 1999 41(8)
      
    Taxus chinensis var. mairei (kemee et Levi. ) Cheng et L.K. Fu is one of the resource plants in China. The taxot contents from different localities are variable. RAPD and HPLC analysis were carried out with 24 samples from 12_localities. A total of 256 loci were amplified among which 224 loci were polymorphic (87.8%). Based on the HPLC and morphological analysis, the relationship among RAPD markers, morphology and habitat was explored. According to the results, high-taxane-contained accessions are present in three localities. This study might be of benefit to the resource conservation and species improvement.
Abstract (Browse 1901)  |  Full Text PDF       
Desiccation Alters the Stability and Distribution of Pea Seed-borne Mosaic Virus in Pea (Pisum sativum) Cotyledon Cells
Author: ZHANG Jing-Feng, LIU Kun-Fan, WEN Yu-Xiang and WANG Dao-Wen
Journal of Integrative Plant Biology 1999 41(8)
      
    As a seed transmitted pathogen, pea seed-borne mosaic vires (PSbMV) not only replicates in embryonic cells but can also withstand seed desiccation. To understand the mechanism of PSbMV tolerance to seed desiccation, the authors compared the stability of viral coat protein (CP) and the distribution of viral particles in the cotyledon cells of pea ( Pisum sativum L. ) embryos collected before and after the dehydration process. Before dehydration, when the embryo was fresh and immature, degradation of CP was observed and a predominantly perinuclear distribution of viral particles in the cotyledon cells was evident. After dehydration, when the embryo was dry and mature, degradation of CP did not occur and the perinuclear viral distribution disappeared. Instead, aggregates containing PSbMV CP were found in the cytoplasm. Electron microscopy showed that these aggregates were composed of PSbMV particles. The formation of PSbMV particle aggregates is apparently triggered by seed dehydration and may be favorable to the virus survival in the desiccated embryonic cells.
Abstract (Browse 1665)  |  Full Text PDF       
Cloning and Characterization of a Circadian Rhythm regulated psaH cDNA in Pharbitis nil
Author: ZHENG Cheng-Chao and ZHANG Xian-Sheng
Journal of Integrative Plant Biology 1999 41(8)
      
    A cDNA clone encoding a PS H subunit of photosystem from Pharbitis nil Choisy was characterized with regard to its sequence and pattern in response to light treatments. The psaH cDNA contained an open reading frame of 432 nucleotides encoding a 144 amino acid protein of approximately 16 kD which consisted of a 49 amino acid transit peptide and a 95 amino acid mature PS I H peptide. Northern analysis indicated that the expression of the psaH gene was regulated by an endogenous circadian rhythm and light was a key factor for promoting its transcription. Moreover, the level of psaH mRNA was rather different among cotyledon, stem and root of the tested seedling.
Abstract (Browse 1778)  |  Full Text PDF       
Cloning and Analysis of CFL-A LFY-like Gene from Cucumber
Author: LIU Fu-Quan, ZHU Guang-Lian, LUO Da, WU Xiang-Yu and XU Zhi-Hong
Journal of Integrative Plant Biology 1999 41(8)
      
    LFY and LFY-like genes have been shown to control the initiation of floral meristems in higher plants. The homologous eDNA of LFY, CFL, were cloned from cucumber ( Cucumis sativus L. ). Southern blot analysis showed it was a single copy gene in the cucumber genome. Northern blot analysis showed that it expressed in the floral buds and young leaves. The possible role of CFL in the floral and vegetative development of cucumber plant was discussed.
Abstract (Browse 1671)  |  Full Text PDF       
Preparation of DNA from Silica Gel Dried Mini-amount of Leaves of Oryza rufipogon for RAPD Study and Total DNA Bank Construction
Author: XIE Zhong-Wen, GE Song and HONG De-Yuan
Journal of Integrative Plant Biology 1999 41(8)
      
    Gene resources of Oryza rufipogon Griff. play a crucial role in rice breeding, and hence to study their conservation is of utter importance. The authors describe a method for preparation of DNA from mini- amotmt of the silica-gel-dried leaves of Oryza rufipogon. The high molecular weight DNAs of 1 168 individuals representing 44 populations have been obtained with high yields, which could be used for RAPD PCR and construction of total DNA bank of this species. The template DNA from silica-gel-dried leaves stored for one year at room temperature gave the same RAPD results as that from the newly prepared silica-gel-dried leaves. The optional template DNA concentrations for amplification ranged from 3.1 ng to 50 ng. In addition, the quality and quantity of the template DNAs that affect RAPD results are also discussed.
Abstract (Browse 1974)  |  Full Text PDF       
Inducible Expression of Translation Elongation Factor 1A Gene in Rice Seedlings in Response to Environmental Stresses
Author: LI Zi-Yin and CHEN Shou-Yi
Journal of Integrative Plant Biology 1999 41(8)
      
    Differences of gene expression between salinity-stressed and control rice ( Oryza sativa L. ssp. indica) cultivar "Zhaiyeqing 8" were compared using differential display PCR (DD-PCR) technique. Sequence analysis of one salt-inducible cDNA clone revealed that this clone represented a new member of rice translation elongation factor lA (eEF1A) gene family and was tentatively named REF1A. Northern blot hybridization using REF1A fragment as a probe was performed to investigate the expression of rice translation elongation factor lA gene in response to various environmental factors. It was observed that expression of the eEF1A gene in rice shoots was dramatically induced by salinity stress or exogenous application of abscisic acid (ABA). The induction of this gene by ABA stress occurred more quickly than that by salinity stress. In addition, expression of rice translation elongation factor lA gene was also induced by drought (15% PEG6000), cold (4 ) or heat-shock (37 ) stresses. The results suggested that the induction of translation elongation factor lA gene expression by environmental stresses might reflect the general adaptive response of rice plants to the adverse circumstances.
Abstract (Browse 2043)  |  Full Text PDF       
Ultracytochemical Localization of Acid Phosphatase in Nucellar Cells of Wheat During Degeneration
Author: TIAN Guo-Wei, SHEN Jia-Heng and YOU Rui-Lin
Journal of Integrative Plant Biology 1999 41(8)
      
    The distribution of acid phosphatase activity in nucellar ceils of wheat ( Triticum aestivum L. ) during degeneration has been studied using the lead precipitation method at the electron microscopic level. Acid phosphatase was localized in the slightly condensed nuclear chromatin in nucellar cells without any sign of ultrastructural degeneration. As the nuceilar cells started degenerating, the enzyme activity in the cell was observed, in the order from small vacuoles to cell walls, mitochondria, plastids and endoplasmic reticulum. Enzyme activity was the highest in most components of the nuceilar ceils adjacent to the embryo sac where the degeneration of nucellar cells was the strongest, but it was not observed in the nuclei of the degenerated nucel]ar cells. The results indicated that the degeneration of nucellar cells was a progressive and orderly process and supported that the degeneration of nuceilar cells was a programmed cell death.
Abstract (Browse 1665)  |  Full Text PDF       
The Existence of Intermediate Filament in Arabidopsis thaliana Cell
Author: ZHAO Da-Zhong, CHEN Dan-Ying, CHEN Min, LIU Chun-Xiang, YANG Cheng and ZHAI Zhong-He
Journal of Integrative Plant Biology 1999 41(8)
      
    The network structure of cytoplasmic filaments of 10 nm in diameter was detected from callus cells of Arabidopsis thaliana (L.) Heynh by selective extraction combined with whole mount electron microscopy. Western blot analysis showed that the major filament components were 6 polypeptides, which reacted with keratin monoclonal antibody of AE1 or AE3 respectively. By indirect immunofluorescence technique, the AE1 and AE3-reactive antigens were localized throughout the cytoplasm in a diffused pattern. The 10 nm-plant filaments could be reassembled in vitro. These results demonstrated that keratin-like intermediate filaments exist in the cytoplasm of A. thaliana. Using conservative sequence of animal IF genes as primer, a cDNA fragment was further cloned from this model material by RT-PCR, which might shed more light on molecular characterization of IF existence in higher plant.
Abstract (Browse 1756)  |  Full Text PDF       
 

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