November 1999, Volume 41 Issue 11

 

          Research Articles
Structure activity Research of Signal Factors Inducing Agrobacterium vir Genes
Author: XU Dong-Hui, XU Shi-Bo, LI Bao-Jian, LIU Yu and GU Lian-Quan
Journal of Integrative Plant Biology 1999 41(11)
      
    Four rice ( Oryza sativa L. cv. IR72) signal factors with the functions of inducing Agrobaterium tumefaciens (Smith et Townsend) Corm vir genes were constructed. They were 5,7,4'-trihydmxy-3', 5'- dimethoxy-flavone (Fl) and its structure analogues F2, F3 and F4. These four signal factors were detected by Agrobacterium vir:: lacZ fusion gene system as to compare their functions of inducing virA, virB, virC, virD, virE and virG genes. The structure characters and stmcture-activity relationship of these signal factors with the best inducing effects to Agrobacterium exogenous gene transformation system were defined which may provide some basic information for foreign gene transformation in rice.
Abstract (Browse 1684)  |  Full Text PDF       
Steroidal Saponins from Speirantha gardenii (Liliaceae)
Author: CHEN Meng-Jing
Journal of Integrative Plant Biology 1999 41(11)
      
    Two new steroidal saponins were isolated from the rhizome of the Chinese native plant, Speirantha gardenii (Hook.) Baill. Their structures were established as 22-methoxy-(25R)-5-furostane-l, 3,4, 5, 26-pentaol 26-O--D-glueopyranoside ( ) and 22-methoxy-(25R)-5-furostane-l, 2, 3, 4, 5, 26-hexaol 26-O--D-glueopyranoside ( ) on the basis of chemical and spectral evidences.
Abstract (Browse 1760)  |  Full Text PDF       
Two New Phenylpropanetriol Glycosides in the Fruits of Melia toosendan
Author: CHANG Jun, XUAN Li-Jiang and XU Ya-Ming
Journal of Integrative Plant Biology 1999 41(11)
      
    Two new phenylpropanetriol glycosides, named as meliadanoside A (3-methoxy-5-hydroxy-9-(l-O--D-glucopyranosyl)-threo-phenylpropanetriol)and meliadanoside B(4-hydroxy-7,8-(2,1-O--D-glucopyranosyl)-phenylpropanetriol), were isolated from the water-soluble extract of the fruits of Melia toosendan Sieb. et Zucc., along with threo-guaiacylglycerol. Their structures were elucidated by spectroscopic and chemical analysis.
Abstract (Browse 1808)  |  Full Text PDF       
Studies on the Changes in Interspecific Association of Zonal Vegetation in Dinhushan
Author: PENG Shao-Lin, ZHOU Hou-Cheng, GUO Shao-Cong and HUANG Zhong-Liang
Journal of Integrative Plant Biology 1999 41(11)
      
    A 15-year change of interspecific association of zonal vegetation, Cryptocarya community, was studied. The results showed that the composition of dominant species in the community structure was not obviously changed in the 15 years. And there were some changes in the interspecific association. Values of the most positive and negative association coefficiem were seldem. The association coefficient between heliophytes and mesophytes were on the increasing. The differentiation of two sub-associations was much more significant. The results indicate the relative stability of the subtropical zonal climatic community, although passive fluctuation as significant.
Abstract (Browse 1838)  |  Full Text PDF       
The Construction of -TIP Prokaryotic Expression Vector and Preparation of the - TIP Antibody
Author: ZHU Mei-Jun,WANG Xue-Chen,CHEN Jia and DU Min
Journal of Integrative Plant Biology 1999 41(11)
      
    A prokaryotic expression vector, pGEX-TIP, was constructed from Arabidopsis thaliana (L.) Heynh. Employing PCR, 205 bp fragment near 3' end of -TIP cDNA, which has specific aquaporin activity, was amplified and cloned into pGEX-KG. Restriction endonuclease analysis and sequencing confirmed the correct construction, and 0.4 mmoL/L IPTC can induce high expression of GST-TIP fused protein which was about 50% in total of E. coli proteins. The IPTG induced E. coli was collected and ]ysed by supersonic treatment. The fusion protein was mainly recovered as an inclusion body. The expressed GST-TIP was purified by SDS-PAGE according to their molecular weight, which was about 32 kD. The purified protein was used to immune rabbits directly or was electrophoretically eluted before it was used for immunization. The highly qualified antibody for GST-TIP was obtained, which provides a very useful protein probe for the research on localization and function of aquaporins.
Abstract (Browse 1731)  |  Full Text PDF       
The Expression Pattern of Xyloglucan Endotransglycosylase Gene in Fruit Ripening of Actinidia chinensis
Author: CHEN Kun-Song, LI Fang and ZHANG Shang-Long
Journal of Integrative Plant Biology 1999 41(11)
      
    To explore the role of xyloglucan endotransglycosylase (XET) in the softening of kiwi fruit ( Actinidia chinensis Planch. ) fruit during fruit ripening, the expression pattern of XET gene in relation to fruit softening was investigated. Northern analysis showed that XET mRNA was in very low level in the fruit at harvest time; treatment with 100 L/L ethylene induced mRNA accumulation, the longer the ethylene treatment, the higher the mRNA level, thus promoted fruit softening. The mRNA level reached the highest at 24 h after ethylene treatment and had no significant change during ethylene climacteric as the ripening fruit stored at 20 . A trace of mRNA level was determined in the fruit stored at 0 while fruit firmness did not change significantly. There was no marked change of mRNA level in the fruit when it was transferred to 20 after storing for 168 h at 0 , however, the fruit softened quickly. It is proposed that XET might be a kind of inductase leading to xyloglucan depolymerization in the fruit cell wall and not play a key role of softening of kiwi fruit after ripening.
Abstract (Browse 1823)  |  Full Text PDF       
Relationship Between Isozymes of Starch Synthases and Starch Composition in Germination Pinyon Seedlings
Author: YAN Hai-Yan and J. B. MURPHY
Journal of Integrative Plant Biology 1999 41(11)
      
    The relation between starch synthases and starch composition in the germinating pinyon ( Pinus edulis Engelm) seedlings was studied. Using the method of 14C-glucose transferred from 14C-ADPG in the assay of starch synthases activity. Starch was extracted with 32% HC1O4, separated on glass fiber with DMSO, and assayed with the sulfuric acid-phenol method. After the emergence of radicle, starch content increased rapidly accompanied with the increase of starch grains in number and size, the increase of both soluble and granulebound starch synthase activity and the change of the pattern of Western-blot. Amylopectin was the major composition in pinyon starch, accounted for 84% of the total starch. The activity of soluble starch synthase was 1.3 times higher than that of the granule-bound starch synthase, corresponding to the ratio of amylopectin to amylose. This result supports the conventional theory that soluble starch synthase is the major enzyme responsive for the synthesis of amylopectin, and also supports that granule-bound starch synthase is functional in the synthesis of amylopectin.
Abstract (Browse 1806)  |  Full Text PDF       
Relationship Between nifZ and the Synthesis of P cluster in Nitrogenase MoFe Protein of Azotobacter vinelandii
Author: HUANG Ju-Fu, WANG Dao-Yong, DONG Zhi-Gang, WANG Zhi-Ping, LI Jia-Ge and WANG Yao-Ping
Journal of Integrative Plant Biology 1999 41(11)
      
    In comparison with OP MoFe protein from wild type strain Azotobacter vinelandii Lipmann, the C2H2-reduction activity and atom ratio of Fe to Mo of nifZ MoFe protein from a nifZ deletion strain of A. vinelandii were remarkably decreased. FeMoco, which were extracted from these two proteins under the same condition, were almost similar to each other in activity and metal composition, and the circular dichroism (CD) spectra of these proteins were significantly different from each other. In the visible region except 540 750 nm, the at 380 - 540 nm of nifZ MoFe protein decreased and had a peculiar sharp negative peak around 430 nm; and in the ultraviolet region, the peaks at 208 nm and 222 nm were higher than those of OP MoFe protein. nifZ MoFe protein could be crystallized in a suitable concentration of PEG 8000 and MgCl2, the size of crystals and amount of precipitation seemed to be related to the above-mentioned negative peaks. The results showed that nifZ of Azotobacter vinelanclii might be related to the synthesis of P-cluster, rather than to that of FeMoco, which resulted in its conformation, stability and process of crystallization.
Abstract (Browse 1733)  |  Full Text PDF       
Isolation and Characterization of -1,4- Endoxylanase from Trichoderma pseudokonigi
Author: ZOU Yong-Long, SANG Yue-Chan, PENG Jian-Xin and WANG Guo-Qiang
Journal of Integrative Plant Biology 1999 41(11)
      
    13-1,4-endoxylanase from Triehoderma pseudokonigi Rifai has been purified by anion-exchange chromatography on DEAE-Sephadex A50, DEAE-Sepharose CL-6B and mono Q. The endoxylanase was shown to be homogeneous by Native-PAGE and SDS-PAGE. This endoxylanase is a single-peptide chain protein with a molecular weight estimated as 66 kD. The endoxylanase was purified by 10-fold with a specific activity of 15.87 Umg1 Optimum endoxylanase activity was obtained when the enzyme was incubated at pH 4.5, 55 with a Km of 20 mg/mL and Vmax of 3.3 molmin1mg1. Hg2 + and Cu2 + have a strong inhibition while Fe2 + and Mn2 + have a increasing effect on the enzymatic reaction rate.
Abstract (Browse 1912)  |  Full Text PDF       
The Synthesis of Insect specific Neurotoxin Gene tox 34 and Acquirement of Transgenic tobacco
Author: MAO Li-Qun and GUO San-Dui
Journal of Integrative Plant Biology 1999 41(11)
      
    A 762 bp mite (Pyemotes tritici) insect-specific neurotoxin tox34 gene fragment encoding mature protein was fully modified based on plant gene codon usage, tox34 was inserted into bacterial expression vector pBV221. Electrophoresis of protein mixture extracted from the bacteria treated with heat-induction showed that specific protein bands migrated with apparent molecular weight of 32 ~ 33 kD in denaturing gels. Tox34 was inserted into plant high-expression vector and then transferred into tobacco (Nicotiana tabacum L. cv. SRI ) using the Agrobacterium tumefaciens (Smith et Tomnsend) Conn binary vector system, followed by the obtainment of the transgenic tobacco plants. The PCR Southern blot assay indicated that the intact toxin gene was integrated into the tobacco genome. GUS assay of transgenic seedling roots showed positive results. The feeding trail of transgenic plants using bollworms (Heliothis armigeva Hubner) manifested strong toxity to lowstar bollworm larvae.
Abstract (Browse 3299)  |  Full Text PDF       
Isolation of High Molecular Weight DNA from Plant Nuclei
Author: QIU Fang, FU Jian-Min and WANG Bin
Journal of Integrative Plant Biology 1999 41(11)
      
    A method of isolating megabase DNA from plant tissue was studied. Generally it includes isolation of purified nuclei by differential centrifugation, embedment of the nuclei in either low-melting-point agarose plugs or microbeads, and digestion with proteinase K in situ to release high molecular weight (HMW) DNA. The results indicated that the size of the prepared HMW nuclear DNA were influenced by both growth period of plant materials and the ways of embedment. The optimal condition for preparing HMW nuclear DNA was to isolate nuclei from the etiolated seedlings or young green leaves and to embedment the nuclei in agarose plugs. The DNA in one plug prepared in this best condition was between 200 kb and 5.7 Mb in size, mostly in the size of 2.25.7 Mb, and approximately 1820 g in amount. Since most of the organellar DNA was removed, the quality of HMW nuclear DNA prepared by this method was greatly improved comparing to those prepared by embedment of protoplast in agarose. The prepared DNA by this method was ready for partial and complete digestion with restriction enzymes and the digestion result was reproducible. The method is very simple and suitable for a wide range of plant taxa. The authors have used this method in isolating HMW nuclear DNA from rice ( Oryza sativa L. ), soybean ( Glycine max ( L. ) Merr. ), apple ( Malus pumila Mill. ), and com ( Zea mays L. ) successfully. The HMW nuclear DNA thus prepared facilitates plant genome analysis by pulsed field gel electrophoresis (PFGE) and construction of yeast and bacterial artificial chromosomal libraries.
Abstract (Browse 2027)  |  Full Text PDF       
Identification and Interaction Analysis of Six Agronomic Trait Loci of Rice Based on a Recombinant Inbred Population
Author: LI Jing-Zhao, HE Ping, ZHENG Xian-Wu, LU Run-Long and ZHU Li-Huang
Journal of Integrative Plant Biology 1999 41(11)
      
    A recombinant inbred line (RIL) population including 107 stable lines was obtained from a cross between an indica variety ZYQ8 and a japonica variety JX17 of rice ( Oryza sativa L. ) through successive selfing up to 9 generations. The quantitative trait loci (QTLs) responsible for six agronomic traits (days to heading, plant height, nmnber of spikelets per panicle, number of grains per panicle, 200-grain weight, seed set percentage) were surveyed and analyzed based on the molecular linkage map constructed from this RIL population. All six traits displayed continuous distribution in the RIL population. For days to heading, two QTLs were identified on chromosomes 8 and 12, of which, qHD-8 was a major gene located on chromosome 8. For plant height, two QTLs were identified on chromosome 1 and 4, of which qPH-1 was a major gene located on chromosome 1. Meanwhile, interaction analysis between these QTLs affecting rice productivity was carried out, and the results showed that there were a total of 24 coadaptive interactions affecting days to heading, plant height, number of spikelets per panicle, number of gains per panicle and seed set percentage, explaining 6.2 % 10.9 % variation respectively.
Abstract (Browse 1891)  |  Full Text PDF       
Pathogen resistant Transgenic Plant from Dwarfing Rootstock of Cherry by Introducing Antibacterial Polypeptide Genes
Author: FANG Hong-Jun, WANG Guan-Lin, WANG Huo-Xu, JIA Shi-Rong, DONG Yun-Zhou and TANG Yi-Xiong
Journal of Integrative Plant Biology 1999 41(11)
      
    A shoot regeneration system of high frequency from shoot of Chinese cherry ( Prunus pseudocerasus Lindl. ) dwarfing rootstock was established and 19 transformed plants were obtained from the dwarfing rootstock by introducing gus gene and antibacterial polypeptide genes, using Agrobacteriuan tumefaciens (Smith et Townsend) Corm as mediator. The results of Southern blot analysis proved that antibacterial polypeptide gene was integrated into the cherry genome. The results of tumor test, X-gluc reaction and bacterial-resistant test of leaf extract against Agrobacterium tumefaciens C58 indicated that antibacterial polypeptide gene may be expressed efficiently in the transformed plant. The tube shoot was characteristic in its resistance to root nodule disease. This study on the characteristics of germ line transformation of shoot meristem suggested that it was a highly efficient transformation system.
Abstract (Browse 1777)  |  Full Text PDF       
Enhancement of Rice Disease Resistance by Two Antifungal Protein Genes
Author: FENG Dao-Rong, XU Xin-Ping, WEI Jian-Wen, LI Bao-Jian, YANG Qi-YUN and ZHU Xiao-Yuan
Journal of Integrative Plant Biology 1999 41(11)
      
    Hasmid pGB12 containing a rice basic chitinase gene RC24 and an alfalfa fl-l, 3-glucanase gene -1,3- Glu and p35H containing hygromycin phosphotransferase gene hpt were simultaneously bombarded into an elite indica rice (Oryza sativa L. ssp. indica ) variety" Qisiruanzhan" grown in South China. 17 independent lines co-harboring RC24 and -1,3-Glu were obtained by Southern blot. Northern blot analysis revealed substantial variations among these transfonnants. The introduced RC24 and -1,3-Glu were stably inherited and expressed in the second and third generations. To the five isolates of Magnaphortha grisea varieties, evaluation of leaf blast of the second generation showed a different degree of resistance. And every progeny of 18 R1 transgenic rice plants showed resistance to the three dominant isolates. Based on bioassay of leaf blast with R2 transgenic rice plants and data from the molecular analyses, ten homologous transgenic lines were primarily obtained, which exerted higher inhibitor efficiency on the growth of Rhizoctonia solani Kiilm.
Abstract (Browse 1819)  |  Full Text PDF       
Elicitation of the Hypersensitive Responses in Tabacco by a10.6 kD Proteinaceous Elicitor from Phytophthora palmi
Author: ZHANG Hong-Ming, CAI Yi-Ying and CHEN Jia
Journal of Integrative Plant Biology 1999 41(11)
      
    A 10.6 kD heat resistant, proteinacious elicitor was purified from the culture filtrate of Phytophthora palmivora Butler but not from P. melonis Katsura. The 10.6 kD elicitor is a holoprotein devoid of glycoside. It can cause hypersensitive necrosis of the detached tobacco ( Nicotiatna tabacum L. ) leaves 48 h post-inoculation with dosages of above 40 g. Four cell types were investigated by using Confocal microscopy, and 2' ,7'-dichlorodihydrofluorescein diacetate (DCFDA) as a probe of H2O2 production. It was showed that oxidative burst occurred in cultured suspension cells as well as in mesophyll cells, epidermal cells and guard cells within 10 min upon the elicitor treatment. The hypersensitive cell death appeared 6 h after the treatment when inoculated with fluorescein diacetate (FDA) as indicator of cell viability. These results suggest that H2O2 accumulation was the main cause of the hypersensitive cell death in tobacco induced by the 10.6 kD elicitor. This 10.6 kD elicitor may belong to the family of elicitins.
Abstract (Browse 1805)  |  Full Text PDF       
Boron Deficiency Causes Changes in the Distribution of Major Polysaccharides of Pollen Tube Wall
Author: YANG Xiao-Dong, SUN Su-Qin and LI Yi-Qin
Journal of Integrative Plant Biology 1999 41(11)
      
    In an attempt to understand the functions of boron in the regulation of pollen tube growth, the structure and localizations of two major polysaccharide components, pectins and callose, in cell walls were studied in pollen tubes cultured in standard medium and boron-deficient medium, respectively. Immunochemical localization of acid pectin and methyl-esterified pectin in the walls of pollen tubes of tobacco ( Nicotiana tabacum L. cv. "Petit Havana" ) and lily ( Lilium longifiorum Thunb. ) was investigated by using monoclonal antibody JIM7 and JIM5 and observed by means of confocal laser scanning microscopy (CLSM). Most of the boron-deficient pollen tubes were remarkably labelled by JIM5 in the wall of tip region, demonstrating an abnormal accumulation of acid pectin in the pollen tube tip, which is the only growth region of the cell. The localization of (1-3)--D-glucan (callose) in the walls of pollen tubes was revealed by ultraviolet excitation of aniline blue staining. The accumulation of callose was also found in the wall of the tipregion of the pollen tubes cultured in the boron-deficient medium. In addition, the changes in the structures of pectins and phenols were investigated by fourier transform intfrared (FTIR) microspectroscopy. It was further confirmed that boron deficiency caused the increment of acid pectin in the pollen tube walls. The increase in the content of phenolics and the decrease in that of phenolic esters were also revealed in boron-deficient pollen tubes. These results imply that boron may function as a regulatory factor of pollen tube growth by affecting the activity of the corresponding enzymes that induce the changes of polysaccharide network and thus the extensibility of the cell wall. The accumulation of free phenolic compounds influences the integrity of plasma membrane, which might also contribute to the regulation of pollen tube growth.
Abstract (Browse 2071)  |  Full Text PDF       
Regeneration of Diploid Intergeneric Somatic Hybrid Plants Between Microcitrus a Electrofusion
Author: LIU Ji-Hong, HU Chun-Gen and DENG Xiu-Xin
Journal of Integrative Plant Biology 1999 41(11)
      
    Leaf-derived protoplasts of Rough lemon ( Citrus jambhiri Lush, 2n = 2x = 18) were electrofused with embryogenic suspension protoplasts of its relative, Microcitrus papuana 5wingle (2n = 2x = 18), with an intention of creating novel germplasm. Six plants were regenerated following protoplasts fusion. Cytological examination demonstrated that they were diploids with 18 chromosomes (2n = 2x = 18). RAPD (random amplified polymorphic DNA) analyses with six arbitrary 10-mer primers showed that the regenerated plants had identical band pattems to those of Rough lemon for primers OPA-07, OPAN-07, OPE-05 and OPA-08, whereas for the other two primers, OPA-04 and OPS-13, bands specific to M. papuana could be detected in the regenerated plants. Cytological and RAPD analysis revealed that the regenerated plants were diploid somatic hybrids between M. papuana and Rough lemon. The putative hybrids were morphologically similar to Rough lemon. This is the first report on production of diploid somatic hybrid plants between citrus with its related genus via symmetric fusion.
Abstract (Browse 1755)  |  Full Text PDF       
Hybridization of Aegilops caudata with Triticum durum, Triticum aestivum and the Detection of Alien Chromatins
Author: KONG Xiu-Ying, ZHOU Rong-Hua, DONG Yu-Shen and JIA Ji-Zeng
Journal of Integrative Plant Biology 1999 41(11)
      
    Aegilops caudata L. carries resistance genes against wheat diseases as well as genes of high crude protein and lysine contents, which can be useful for wheat improvement. An amphiploid of Triticum durum - Ac. caudata was synthesized and the hybridization of T. aestivum with the amphiploid Am 8 was carried out. Chromosome in situ hybridization was carried out for the PMC (pollen mother cell) of the synthesized amphiploid (AABBCC) and ( T. aestivum Beijing 837 Am 8) F2 by using the pAeca 212 as a probe. The results showed that the 7 bivalents from C genome had hybridization signals in the amphiploid. The detection for F2(Beijing 837 Am 8) indicated that translocation, even (pure) home translocation, occurred in F2 generations spontaneously. The study showed the bright prospect in transferring alien resistance genes from C genome to wheat.
Abstract (Browse 1743)  |  Full Text PDF       
Ultracytochemical Localization of Acid Phosphatase During Differentiation and Dedifferentiation of the Secondary Xylem in Eucommia ulmoides Trunk
Author: WANG Ya-Qing, CHAI Jing-Jing and CUI Ke-Ming
Journal of Integrative Plant Biology 1999 41(11)
      
    The role of acid phosphatase (APase) played in the differentiation and dedifferentiation of the secondary xylem in Eucommia ulmoides Oliv. in respect of enzyme localization was studied. APase was initially prominent along the nuclear membrane and in the dictyosomes of the young xylem parenchyma cells, and present in the whole nucleus in the highly differentiated cells. At a later stage of differentiation of the xylem parenchyma cells , APase was concentrated in the debris of other organelles and along the cell wall in the mature cells. APase aggregated in the nucleus, plasma membrane and pits of the immature vessel element, from which part of the plasma membrane became indistinct or disappeared and the nucleus eventually degenerated. APase mainly aggregated along the primary cell wall of the nearly mature vessel element, and in the secondary cell wall in the mature vessel element. On the 1st and 2nd day after girdling, the enzyme was sparsely scattered in the cytoplasm during the dedifferentiation of the xylem parenchyma cells. On the 4th and 7th day after girdling, APase was present in the cytoplasm of the dilated xylem parenchyma cells in the surface layer and also that of the adjacent dedifferentiating parenchyma cell. On the 14th and 21st day after girdling, few APase was found in the cytoplasm and none in the cell wall of the inner immature dedifferentiating vessel element. The localization of APase in the secondary xylem formed from the new cambium was as similar as that in the normal vascular tissue, and that in the mature and nearly mature vessel element that could not dedifferentiate after girdling was the same as that before girdling. Comparison of the distribution of Apase activity between the differentiation and dedifferentiation stages of the secondary xylem indicates that different isoforms of APase may respectively play functions in the protoplast degeneration and the secondary wall formation during programmed cell death of the secondary xylem. The intensity of APase activity may be an important decisive characteristic in cell dedifferentiation.
Abstract (Browse 1840)  |  Full Text PDF       
An Ultrastructural Study of the Development of Blepharoplast and the Origin of Multilayered Structure in the Sperm of Lygodium japonicum
Author: LIU Zhao-Hui, LIU Ning and ZHOU Yun-Long
Journal of Integrative Plant Biology 1999 41(11)
      
    The blepharoplast, an elliptical, compact spherical body ranging 0.50.6 /m in diameter, appears in the cytoplasm of the sperm mother cell during the sperm development of Lygodium japonicum (Thunb.) Sw. It consists of cartwheel tubular subunits arranged in radiant pattern and amorphous material. Numerous microtubules extended from the blepharoplast into cytoplasm. In the process of sperm cell development, the blepharoplast became loose, and the centrioles originated from the subunits separated from each other and dispersed towards the surface, with the amorphous material in the center. Accompanying the differentiation of the centrioles, muhilayered structure with the spline ( i. e. microtubular band) and lamella strata came into existence, with one end attaching to the amorphous material in the center. Then the muhilayered structure (MIS) associated with a mitochondrion and moved towards the nucleus, and a dent facing the MIS is formed in the nucleus. A cotton-like structure consisting of amorphous material and dardyed small tubular structure appeard in late stage of spermatogenesis. Microtubules were seen protruding from the surface of the cotton-like structure. It is suggested that this structure might be relevant to the origin of the blepharoplast.
Abstract (Browse 1715)  |  Full Text PDF       
Cytogenetic Studies on the Cross generations Between Triticum aestivum and Eremopyrum orientale
Author: ZHANG Gui-Fang, LIU Jian-Wen, HUANG Yuan-Zhang, DING Min, TANG Shun-Xue and JIA Xu
Journal of Integrative Plant Biology 1999 41(11)
      
    The cytogenetics of the backcross generations and self-bred progenies (BC2F1, BC3F1, BC2F2, BC3F2 and BC2F3) of intergenetic hybrid of Triticum aestivum L. x Eremopyrum orientale (kedeb) Jaub. Et Spach were studied. The results showed that the plants BC3F1 (2n = 43 ) isolated from the backcross generations of the plants (2n = 44 ) accounted for 41.09%, but the plants (2n = 44) isolated was only 4. 11%, and the plants BC2F2 (2n = 44) isolated from self-cross generations of the plants BC2F1 (2n = 44) accounted for 13.21%. The number of univalents in pollen mother cells was higher in some plants (BC2F1) and the averages of univalents were negatively related to the backcross seed-setting and self-cross seed-setting with a related coefficient of 0.6766* and 0.7429* respectively. The results of genomic in situ hybridization (GISH) showed that some plants of BC2Fs (2n=44) contained different number of alien chromosomes. All those indicated that alien chromosomes caused unusual pairing and segregation of wheat homologous chromosomes and also lowed the hereditary stability of wheat chromosomes.
Abstract (Browse 1714)  |  Full Text PDF       
Distribution of Trans zeatin, GA7/4, (+)ABA and IAA in Tobacco Egg Cells Before and After Fertilization: Immunogold Electron Microscopic Observations
Author: CHEN Yi-Feng, LIANG Shi-Ping, YANG Hong-Yuan and ZHOU Xie
Journal of Integrative Plant Biology 1999 41(11)
      
    Changes in distribution of trans-zeatin (t-Z), gibberellin A7 and A4(GA7/4), ( + )abscisic acid [( + )ABA] and indoleacetic acid (IAA) in the egg cells of Nicotiana tabacum var. macrophylla before and after fertilization were studied with immunoelectron microscopy. The ovules just at pollination or 96 h after pollination were fixed with 2% EDC [ 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide] and then with the mixed paraformaldehyde and glutaraldehyde for acidic phytohormones (or only with the aldehydes for t-Z), then slightly posffixed in 0.5% OsO4 solution for 30 min. After etched in 1% H2O2 for 10 min, the ultrathin sections embedded in Epon 812 resin were immunostained with rabbit anti-t-Z (and t-ZR) polyclonal antibody (PAB), anti-lAA methyl ester PAb, mouse anti-GA7 and GA4 methyl esters monoclonal antibody(MAb), or anti-( + ) ABA methyl ester MAb, respectively. Protein A- or sheep anti-mouse IgG-colloidal gold ( 10 nm) were used to indicate rabbit PAbs or mouse MAbs respectively. In the model system of nitrocellulose membrane via immunogold-silver enhancement, the authors ascertained that immunostaining results at the basis of 1 ng per phytohonnone (t-Z, IAA, GA4, or ( + )ABA) were comparable among the four-kind phytohormones and that t-Z riboside was far less fixed than t-Z with aldehydes. So the anti-t-Z PAb mainly recognized t-Z in aldehyde-fixed tissues. Immunogold electron microscopic observations showed that t-Z was rich in the egg cells before fertilization. In contrast the amounts of GA7/4 and ( + )ABA were lower in egg cells before fertilization but slightly increased after fertilization. Less IAA in egg cells was found either before or after fertilization, t-Z in unfertilized egg cells appeared to concentrate on the nucleus, endoplasmic reticulnm and mitochondria, t-Z is rarely observed in the nuclei of synergids before fertilization but is abundant in the chalazal end of synergids and micropylar end of the central cell adjacent to the unfertilized egg cell. After fertilization, t-Z decreased bviously in the zygotes and the persistent synergids, but appeared in the thickened walls of the zygotes.
Abstract (Browse 1787)  |  Full Text PDF       
Relationships Among Hormone Changes, Transmembrane Ca2+ Flux and Lipid Peroxidation During Leaf Senescence in Spring Maize
Author: HE Ping and JIN Ji-Yun
Journal of Integrative Plant Biology 1999 41(11)
      
    45Ca2+ absorption by plasma membrane vesicles isolated from maize (Zea mays L. ) leaves cultured in vitro was assessed to investigate the relationships among hormone changes, transmembrane Ca2+ flux and lipid peroxidation during leaf senescence. The results suggested that the possible process of leaf senescence in spring maize followed a sequence of endogenous hormonal change then transmembrane Caa + flux which further led to lipid peroxidation, with consequent degradation of chlorophyll and protein.
Abstract (Browse 1712)  |  Full Text PDF       
 

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