March 1999, Volume 41 Issue 3

 

          Research Articles
Effects of Water Stress on the Cyanide resistant Respiration and Expression of the Alternative Oxidase Gene in Wheat Seedlings
Author: HE Jun-Xian, WEI Zhen-Quan, LIN Hong-Hui and LIANG Hou-Guo
Journal of Integrative Plant Biology 1999 41(3)
      
    The effects of water stress on the development and operation of an alternative respiratory pathway and the expression of an alternative oxidase gene in wheat ( Triticum aestivum L. cv. Longchun No. 16) seedlings were investigated. When the roots of the seedlings were osmotically stressed with 0.5 MPa polyethylene glycol ( PEG 6000) solutions for 24, 48 and 72 h, the leaves were subjected to mild, moderate and severe water stress respectively, while the roots only received mild water stress throughout the stress treatment as reflected by changes in relative water content (RWC). In response to the water-stress conditions, the alternative pathway capacity (Vast), the alternative pathway activity (pValt) and its contribution to total respiration ( pValt/Vt ) of leaves decreased progressively, while these parameters of roots were found to decrease at the first 24 h of stress and thereafter recover to the levels close to that of the control (0 h). These data indicate that the alternative pathway is sensitive to water stress and is adaptive to mild water stress. The results of Northern hybridization performed with total cellular RNA and an alternative oxidase gene (Aox) probe revealed that there was a good correlation between Vat (also p Valt ) and the level of Aox mRNA in both leaves and roots, suggesting that the water stress-induced decrease in the development and operation of alternative pathway was due, at least in part, to the inhibition of expressional synthesis of the alternative oxidase protein.
Abstract (Browse 1890)  |  Full Text PDF       
Acosmid Library Constructed to the Elite Rice Cultivar
Author: PENG Kai-Man and ZHANG Qi-Fa
Journal of Integrative Plant Biology 1999 41(3)
      
    A genomic DNA library was constructed to the elite rice cultivar "Minghui 63" using the cosmid SuperCosl as the vector. The library consisted of 45 000 clones with average insert size about 40 kb. It was estimated that this library had a capacity of 4.2 times equivalent of the haploid genome of rice.
Abstract (Browse 1725)  |  Full Text PDF       
Transformation and Expression of Trichosanthin Gene in Tomato
Author: JIANG Guo-Yong, JIN De-Min, WENG Man-Li, GUO Bao-Tai and WANG Bin
Journal of Integrative Plant Biology 1999 41(3)
      
    Trichosanthin (TCS) is a type-I ribosome inactivating protein. Previous studies indicate that TCS has antivirus effect on HIV, HBV, TMV and many other viruses. The authors report that TCS gene was integrated into binary transformation vector pBI121-2 and a new recombinant plasmid pBI121TG24 containing the recombinant TCS-GUS gene was obtained, pBI121TG24 was transferred into Agrobacterium tumefaciens strain LBA4404 and a new genetic engineered strain pBI121TG24/LBA4404 was obtained, pBI121TG24/LBA4404 was used to transform the tomato ( Lycopersicon esculentum Mill. ) eultivar "Peak" and "Meitin 11" by the conmmon leaf-disc method. Results indicated that TCS gene was integrated into tomato genomic DNA evidenced with assays of kanamycin screening X-glu detection, PCR amplification, dot blot and Southem blot. The transformation efficiency of TCS gene was 1.13% for "Peak" and 0.72% for "Meiyin 11". The transgenic plant TP3, TP11 have shown virus-resistance on TMV and CMV.
Abstract (Browse 1782)  |  Full Text PDF       
Middle Jurassic Sporopollen Assemblage from the Yan'an Formation in Binxian County, Shaanxi Province and Its Significance
Author: YIN Feng-Juan and HOU Hong-Wei
Journal of Integrative Plant Biology 1999 41(3)
      
    Abundant spores and pollen grains including 60 genera and 83 species were collected from the Yan'an Formation in Binxian County, Shaanxi Province. In this assemblage gymnospermous pollen grains amounted to 51.2%, among which Cycadopites made up 27.2% and Quadraeculina 7.2%, also including a certain amount of other genera such as Monosulcites, Eucommiidites, Cerebropollenites, Chasmatosporites, Pinuspollenites , Piceaepoltenites , Piceites Podocarpidites , Psophosphaera , Araucaracites , Classopollis , Callialasporites, etc. Pteridophyte spores amounted to 48.8%, among which Cyathidites made up 21.4%; Deltoidospora 9.1% and Duplexisporites 3.1%. Osmundaciclites , Granulatisporites , Lycopodiumsporites , Neoraistrickia, Densoisporites, Microreticulatisporites, Undulatisporites, Cibotiumsporites, Gleicheniidites, Concavissimisporites, Cyclogranisporites, etc, each constituted less than 3%. Based on stratigraphical ranges of certain important known species and comparison with those from other regions in China and Western Canada, the sporopollen assemblage of the Yan' an Formation under study may be assigned to Middle Jurassic in age. Its palaeovegetation and palaeoclimatic conditions are also discussed.
Abstract (Browse 1754)  |  Full Text PDF       
Fractal Analysis of Grass Patches Under Grazing and Flood Disturbance in an Alkaline Grassland
Author: XIN Xiao-Ping, GAO Qiong, LIN Yi-Yin and YANG Zheng-Yu
Journal of Integrative Plant Biology 1999 41(3)
      
    A fractal analysis was performed for grassland patterns on the Songnen plain in Northeast China, a region with extremely heterogeneous vegetation because of alkalization. Four belt regions were selected according to the different grazing intensity and the flood condition in 1994. Field measurements on patch shape and size of plant communities were carded out along each region in 1997. The perimeter-area exponent and Korcak exponent were evaluated by regression method to determine the fractal dimension of the patch boundary and patchiness of the grassland. 1. The patchiness (Korcak exponent) of Leymus chinensis (Trin.) Tzrel, the dominant species of zonal vegetation, increased with the grazing gradient. The perimeter-area exponent (complexity of boundaries) was the highest (0.64) in the lightly grazed grassland, and lower in the forage grassland (0.56) and the heavily grazed grassland (0.59). 2. Both perimeter-area exponent and Korcak exponent of L. chinensis and two subdominant species (Puccinellia spp. and Aeluropus littoralis (Gouan) Parl. var. sinensis Debeaux) of zonal vegetation were lower in the flooded than in the non-flooded grassland. The possible reason is that flood reduces the heterogeneity of soil alkali. 3. In forage grassland, both Korcak exponent and perimeter-area exponent of the dominant species were lower than that of the sub-dominant species, but showed converse results in the heavily grazed flooded grassland. 4. Four of the six Durbin-Watson tests of regression evaluating Korcak exponent displayed significant autocorrelation in residuals. It can be concluded that the dynamics of patchiness occurred on at least two scales in the present data range. No significant autocorrelation was observed in residuals of regression evaluating perimeter-area exponent. It revealed that patchiness and complexity of boundary, had different scale regions.
Abstract (Browse 1897)  |  Full Text PDF       
Research on Regulation of NDVI Change of Chinese Primary Vegetation Types Based on NOAA/AVHRR Data
Author: LI Xiao-Bing and SHI Pei-Jun
Journal of Integrative Plant Biology 1999 41(3)
      
    Supported by the Remote Sensing, Geographic Infonnation System and Global Positioning System, using continuous time series of NOAA/AVHRR Normalized Difference Vegetation Index (NDVI) digital image with spatial resolution of 1 km x 1 km as data resources, according to Principal Components Analyses and unsupervised classification, Chinese vegetation was classified into 35 vegetation types and 9 groups, with the assistance of various basic maps and annual seasonal change of NDVI. By reconstruction of the various processes of NDVI of various vegetation types during 10 years, four regions, in which the changing process of NDVI of various internal types were relatively consistent, were assigned. These four regions show obviously zonal distribution from southeast to northwest. By estimating the correlation among NDVI changes, the four regions were further integrated into two primary regions of higher order, with their regional boundary tallied with the northwest border of the eastern monsoon region of the three natural regions in China. Furthermore, regionalization was worked out on the NDVI changing perspective, including two first-class regions and nine second-class regions.
Abstract (Browse 1928)  |  Full Text PDF       
Genetic Diversity and Clonal Structure of Hedysarum laeve in Mo Us Sandland
Author: GE Song, WANG Ke-Qing and DONG Ming
Journal of Integrative Plant Biology 1999 41(3)
      
    Genetic diversity and clonal structure of eight populations of Hedysarum laeve Maxim. in sandland were studied using starch gel electrophoresis. Allozyme data of 15 loci of 10 enzymes indicated relatively high levels of genetic variability in this species with a proportion of polymorphic loci P = 37.0 and an average number of alleles per locus of A = 1.48 and an average expected heterozygosity of He = 0. 101. It exhibited a low degree of population differentiation among the eight populations with GST value of 0.067. There was no significant difference of the genetic diversity between the populations in the fixed dunes and in the semi-fixed dunes. The clonal diversity was very high (D = 0.915 6) in H. laeve populations according to the analysis based on 7 polymorphic loci. The sizes of different clones, however, varied greatly. In addition, there was great clonal differentiation among populations with only 3.2 % of the widespread genotyes. The analysis of clonal structure demonstrated that the spatial distribution pattern of H. laeve clones was one of the guerilla architectures.
Abstract (Browse 1764)  |  Full Text PDF       
Unequal Distribution of 6 methoxy-2- benzoxazolinone(MBOA)Is the Main Reason for Phototropism in Maize Coleoptiles
Author: CHEN Ru-Min
Journal of Integrative Plant Biology 1999 41(3)
      
    The distribution of 6-methoxy-2-benzoxazolinone (MBOA) which is induced by blue light stimulation in maize ( Zea mays L. ) coleoplile was investigated by HPLC analysis. The results showed that: 1. The MBOA content on the irradiated side of the coleoptile was 1.5 fold more than that on the shaded side. 2. There was little change of IAA on both sides of the coleoptile which was treated with phototropic stimulation. 3. The growing coleoptile bent towards the side which was treated with MBOA, 5,6-dimethoxy-2-benzoxazolinone (DMBOA) or 2-chloro-5,6-dimethoxy-2-benzoxazolinone ( C1-DMBOA). The above results indicated that the phototropic bending of the coleoptile was attributed to unequal distribution of MBOA.
Abstract (Browse 1861)  |  Full Text PDF       
Purification and Characterization of Glycerol-3-phosphate Dehydrogenase in Dunaliella salina
Author: ZHANG Xue-Wu and LIU Cheng-Xian
Journal of Integrative Plant Biology 1999 41(3)
      
    Glycerol-3-phosphate dehydrogenase (EC1.1.1.8)has been isolated from the unicellular green algae Dunaliella salina (Dunal) Teed. and the electrophoretic homogenous enzyme was obtained by PEG fractionation and column chromatography on DEAE Sepharose Fast Flow, Blue Sepharose CL 6B and Mono Q HRS/5. The purified enzyme has a specific activity of 12.6 U/mg and a molecular weight of about 270 kD determined by native gradient polyacrylamide gel electrophoresis (4% to 20% acrylamide). The enzyme has only one kind of 65 kD subunit determined by SDS-PAGE. Combining the results from the two kinds of electrophoresis, the authors deduce that the enzyme may be a tetramer. The optimum pH is 7.5 for reduction of dihydroxyacetone phosphate (DHAP) and 10 for glycerol-3-phosphate (G-3-P) oxidation. The apparent Km for reduced nicotinamide adenine dinucleotide (NADH), DHAP, nicotinamide adenine dinucleotide (NAD), G-3-P are 63 ¦̀mol/L, 272 ¦̀mol/L, 1.53 mmol/L, 6.52 mmol/L, respectively. The enzyme is unstable during storage. NADH can delay activity losing, but NAD can not. NaC1 at low concentration protects the enzyme, whereas at high concentration NaC1 accelerates the activity loss of the stored enzyme. The higher the concentration, the faster the activity loss.
Abstract (Browse 1854)  |  Full Text PDF       
Effects of HCO3£­ on Surface Calcification and CO2 Fixation in Marine Emiliania huxleyi
Author: WU Qing-Yu, SHIRAIWA Yoshihiro
Journal of Integrative Plant Biology 1999 41(3)
      
    Emiliania huxleyi is a ubiquitous species with the largest biomass in marine planktonics. When cells of E. huxleyi were grown in ESM with additional 20 mmol/L HC03- , coccolith scales were formed on cell surface and the weight ratio of calcium carbonate fixed in coecoliths to organic substance in cells was about 2.47: 1. It was only about 0.05: 1 in cells grown in ESM without HCO3- addition, where no coccoliths were observed under scanning electron microscope, and the content of lipid reached 18.1% of dry. cell weight. It was demonstrated that the HCO3- concentration was the key factor to control the calcification on cell surface. Therefore, in addition to the pathway of photosynthesis for CO2 fixation, calcification on cell surface forming coccoliths is an alternative pathway for fixing dissolved inorganic carbon in E. huxleyi. Moreover, being rich in lipids, E. huxleyi cells produced high content of hydrocarbons including extractable organic matter, saturates and aromatics under pyrolysis at 300¡æ. Among those, the yield of saturates from E. huxleyi reached as high as 2.8%, 6-15 times that from other algae. All these suggest that E. huxleyi is a good experimental system for studies on the optimization of environment through carbon cycle and renewable energy in algal biomass.
Abstract (Browse 2135)  |  Full Text PDF       
Expression and Sequence Analysis of a cDNA Relative to Orchid Ovule Development
Author: WANG Ling, ZHANG Xian-Sheng, ZHONG Hui-Wen and LI Quan-Zi
Journal of Integrative Plant Biology 1999 41(3)
      
    The Phalaenopsis sp. cv. SM 9108 flower provides a good system to isolate ovule-specific genes. A cDNA library at mature ovule stage has been constructed. A differential screening approach was used to identify cDNAs representing genes which are expressed in a stage-specific manner during ovule development. The authors have demonstrated that the expression of a cDNA (0138) was regulated stage-specifically and tis-sue-specifically using, Northern blot, and also have analyzed the full sequence of this cDNA. Its further functional characterization in ovule development will be facilitated.
Abstract (Browse 1741)  |  Full Text PDF       
Characterization and Structural Analysis of a SOD-like Material from Rose Fruit
Author: GU Xue-Song, LIN Yong-Qi and ZHU Yu-Xian
Journal of Integrative Plant Biology 1999 41(3)
      
    It is known that SOD activity in rose ( Rosa rugosa var. chamissoniana) fruit is very high. By organic solvent fraction and dialysis, the authors found that the substance of scavenging 02- is mainly a material with low molecular weight (termed as SOD-like material). Ultraviolet spectrophotometry, CD spectra, amino acids analysis and iron determination of the purified peptide indicated that it has approximately 70 amino acids and one atom of iron per molecule. The Cys content of SOD-like material is higher than that of SOD. In the ultraviolet region, a peak at 280 nm was observed. CD spectra showed a characteristic peak of random coil. The N-terminal group of this molecule, as determined by Pansyl Chloride method, was not enzymatically cleaveable. This SOD-like material also has very high temperature and acidic stability.
Abstract (Browse 1782)  |  Full Text PDF       
Cloning of the LFY cDNA from Arabidopsis thaliana and Its Transformation to Chrysanthemum morifolium
Author: SHAO Han-Shuang, LI Ji-Hong, ZHENG Xue-Qin and CHEN Shou-Cai
Journal of Integrative Plant Biology 1999 41(3)
      
    The total length cDNA of Leafy (LFY) was cloned and sequenced from wild type Arabidopsis thaliana (L.) Heynh. The plant expression vector with CaMV 35S promoter for LFY cDNA was constructed and transformed into Chrysanthemum morifolium (Ramat.) Tzvel. The result proved that the LFY eDNA contained 1 263 base pairs in total length, encoding 420 amino acid. After Southern and Northern blot analyses the plants were grown in flowerpot, eight transgenic Ch. morifolium, plants were obtained. Compared with the normal plants, three of them flowered 65,67 and 70 days earlier and two of them delayed flowering 78 and 90 days, respectively.
Abstract (Browse 1948)  |  Full Text PDF       
Cloning and Expression of a cDNA Encoding Endopolygalacturon ase from Feicheng Peach (Prunus persica)
Author: MA Qing-Hu, WANG Li-Mei, SONG Yan-Ru and ZHU Zhi-Qing
Journal of Integrative Plant Biology 1999 41(3)
      
    Polygalacturonase (PG, EC3.2.1.15) is the key cell wall hydrolase in fruit ripening. The identification and characterization of a full-length cDNA(pMT18) encoding for PG from Feicheng peach ( Prunus persica (L.) Batsch cv. Feicheng) is described. The pMT18 clone is 1 188 bp in length, with an open reading frame of 393 amino acids. The homology and phylogenetic analyses indicate a remarkable similarity between peach PG and other ripening-related PG. And seven consensus sequences have revealed in peach PG compared to the PG from other plants. However, the profound divergence with other PG and the unique structure features suggest that peach PG probably belongs to a new evolutionary class. In RT-PCR analysis, pMT18-related RNA was undetectable in leaves, and was much abundant in ripe fruits. The ripening-specific expression pattern of this cDNA will be useful in investigating the roles of PG in fruit ripening and developing a transgenic peach with the improved pest-harvesting quality in the future.
Abstract (Browse 2024)  |  Full Text PDF       
Study on Chromosome Cbanding in Leymus racemosus and Its Related Species
Author: WANG Su-Ling, QI Li-li, CHEN Pei-Du and LIU Da-Jun
Journal of Integrative Plant Biology 1999 41(3)
      
    The karyotype analyses with chromosome C-banding were carried out in Thinopyrum bessarabicum (Savul. & Rayss. ) A. love, Psathyrostachys juncea (Fisch.) Nevski and Leymus racemosus (Lam.) Tzvel. The C-banding patterns between Th. bessarabicum and P. juncea were distinctively different, indicating the interspecific differentiation. Most of the C-bands distributed on chromosome telomere in Th. bessarabicum, P. juncea and L. racemosus, being more prominent in L. racemosus than in Th. bessarabicum and P. juncea. Most chromosomes of the three tested species lacked centromeric bands and intercalary bands. In C- banded karyotype of L. racemose, the banding patterns of some Leymus chromosome were similar to those in Th. bessarabicum and P. juncea. The genome relationships among Th. bessarabicum, P. juncea and L. racemosus were discussed.
Abstract (Browse 1818)  |  Full Text PDF       
Comparative Physical Location of Rice Xa 21 Gene in Rice and Maize Using the BAC-FISH Approach
Author: YAN Hui-Min, SONG Yun-Chun, LI Li-Jia, LI Xia and FU Bin-Ying
Journal of Integrative Plant Biology 1999 41(3)
      
    In grasses, comparative genome analyses have demonstrated that there were widespread syntenies and colinearities of the genes among different species within a family. As a model genome, analysis of the rice ( Oryza sativa L. ) genome has allowed us to reveal the basic evolutionary units of the cereal genomes. The authors used a rice genomic clone of the gene Xa21 inserted in the plasmid pBluescript as a probe to screen rice bacterial artificial chromosome (BAC) library. A contig of three BAC clones was constructed. One of the BAC clones was adopted as the tested probe. The tested plants were O. sativa subsp, indica cv. "Guang Lu Ai 4" and the inbred line of Zea mays cv. Huang Zhao 4. The biotin-labeled BAC clone was hybridized onto the rice and maize metaphase chromosomes by fluorescence in situ hybridization (FISH). The Xa21 cloned in Bluescript was also hybridized onto the maize chromosomes. The results obtained from the BAC and plasmid clones were the same. In rice, the Xa21 was located in the long arm of the chromosome 11, the percent distance from the centromere to the signal was about 24. This result was in accordance with the rice genetic map. In maize, three hybridized sites were detected ant located on the long arms of chromosomes 1, 3, and 8 respectively. It suggested that the homologous sequences of Xa21 were triplicated in maize. By BAC-FISH technique, the detection rate was over 40 %, much higher than that by FISH with plasmid clones, for which it was only about 15%. Moreover, the rate of signals which were detected simultaneously on two members of a homologous chromosome pair and sister chromatids was higher by BAC-FISH technique than that by FISH with plasmid clones. It demonstrated the feasibility and advantage of BAC-FISH technique in gene comparative physical location. Cot I DNA was necessary for blocking the nonspecific DNA because the tested results were interfered seriously by repeated sequences. The signals could be found on many chromosomes without blocking.
Abstract (Browse 1967)  |  Full Text PDF       
Floral Syndrome and Insect Pollination of Liriodendr on chinense
Author: HUANG Shuang-Quan,GUO You-Hao, PAN Ming-Qing and CHEN Jia-Kuan
Journal of Integrative Plant Biology 1999 41(3)
      
    In studying the relationship between floral syndrome and pollen transfer in an endangered plant Liriodendron chinense (Hemsl.) Sarg., three natural populations in Guizhou, Hunan and Zhejiang Provinces of China were respectively chosen for the field work throughout the florescence. The role of wind-pollination in this species could be ignored as the pollen quantity decreased rapidly with the increasing distance. In spite of morphological protogyny, pollen viability and the life-span of receptive stigmas overlaped more than 24 h. Anatomically, anther sac has four locules with unequally thickened endothecium which may affect anther to dehisce. There were many secretory cells (and groups of fluorescent cells) at the base of petals and styles, but PAS reaction indicated that polyhexose was mostly concentrated in the cells around the vascular bundle of petals. Fluorescent cells and flower fragrance were regarded as attractants, nectar and pollen as rewards to visitors. The floral syndrome seems to be adaptive to insect pollination. During 1994 to 1996, a total number of thirty-nine species of insects including bees, flies and beetles were recognized as the flower visitors. Among which only four were present in all the three populations. The visiting frequency varied distinctly from species to species and among populations. While bees were observed as the most frequent visitors in the population in Guizhou Province, they were substituted by flies in the other two populations in Hunan and Zhejiang Province, and became occasional visitors themselves. The beetles, despite of their frequent activity in flowers, played a much less important role in cross-pollination. Comparing the mean pollen numbers deposited on stigmas pervisit, it was found that bees were much more effective than flies in pollination. SEM examination of insect body also supported this point. Moreover, the visiting frequency was also observed to be closely associated with the characters of flower blossom. Visitors preferred to visit those flowers in early anthesis. Treatments of emasculation and perianth removal showed that the rewards of nectar was more attractive than pollen to pollinators. This species is tend to be cross-pollinated by insects but without its faithful pollinators.
Abstract (Browse 2008)  |  Full Text PDF       
Obtaining Homozygote of Taigu Genic Maleª²sterile Wheat by Chromosome Elimination
Author: SUN Jing-San, LU Tie-Gang and XIN Hua-Wei
Journal of Integrative Plant Biology 1999 41(3)
      
    The fertility of the Taigu genic male-sterile wheat is controlled by single dominative male-sterile gene Tal. So all the male-sterile plants are heterologous (Tal tal ), and homologous male-sterile plants ( Ta 1 Ta 1 ) do not exist in nature. In this work, based on the phenomenon of autonomous paternal chromosome elimination in wheat ( Triticum aestivum L. ) x maize ( Zea mays L. ) cross, the Taigu genic male-sterile wheat was used as maternal plant to cross with maize, and through the process of hormone treatment, embryo rescue and chromosome doubling, new germplasm of homologous dominative Taigu male-sterile wheat ( Ta 1 Ta 1 ), which never existed in nature, were successfully obtained. And this new precious germplasm was retained through long-term cryopreservation by vitrification.
Abstract (Browse 1833)  |  Full Text PDF       
Distribution of NuMA-like Proteins and Its Changes During Cell cycle in Plant Cells
Author: SUN Ying-Li, ZHAO Yun, WANG Jian and ZHAI Zhong-He
Journal of Integrative Plant Biology 1999 41(3)
      
    Immunofluorescence staining with anti-animal NuMA antibodies revealed the existence of NuMA protein-like components in carrot ( Daucus carom L. ) suspension cells and the NuMA-like proteins exhibited regular distribution during mitosis. Furthermore, immunofluorescence staining of the nuclei after cell extraction revealed that the NuMA-like proteins were components of nuclear matrix proteins and the nuclear matrix changed obviously during mitosis. Western blot with anti-animal NuMA antibodies identified two positive bands of the nuclear matrix components with molecular weight of 74 kD and 76 kD. Using selective extraction and diethylene glycol distearate (DGD) embedment and embedment-free electron microscopy, the well-organized nuclear matrix network was observed in interphase carrot cells but not in cells during metosis. These results suggest that NuMA-like proteins are components of nuclear matrix, and are closely related with mitosis.
Abstract (Browse 1766)  |  Full Text PDF       
Generation of Hydroxyl Radicals and Its Relation to Cellular Oxidative Damage in Plants Subjected to Water Stress
Author: JIANG Ming-Yi
Journal of Integrative Plant Biology 1999 41(3)
      
    The hydroxyl radical ('OH) is one of the roost reactive mdieales known to chemistry and is believed to be a major active free radicle responsible for modifications of macmmolecules and cellular damage. Two lines of evidence strongly indicate that 'OH radicals are generated in a Fenton-type Haber-Weiss reactions in plants subjected to water stress. Firstly, water stress causes an increase in the concentration of catalytic metals, which are critical for Fenton-like reactions to proceed in vivo. Furthermore, subrmillimolar concentrations of H2O2 and ascorbic acid(or O2£­ ) in the drought-stressed plants are large enough to support the Fentontype Haber-Weiss reactions. Secondly, there is oxidation of proteins and lipids in the drought-stressed plants; a process that requires a catalytic metal and that, at least for protein oxidation, is mediated by the 'OH radicals. Protein oxidation is thought to involve binding of metal ions to the proteins and subsequent site-specific attack by the 'OH radicals arising from the roetal-catalysed decomposition of H2O2. It has been proposed that protein oxidation may be a better index than lipid peroxidation because the latter fields many different products and these only appear after a lag period. The validity of malondialdehyde (MDA), an early product of lipid peroxidation, as an index of lipid peroxidation has been argued by the non-specific method of its measurement. The 'OH radicals are not the only necessary initiator for lipid peroxidation and lipid peroxidation is not usually involved in plants exposed to water stress.
Abstract (Browse 1955)  |  Full Text PDF       
Resonance Raman Spectra of Purified PS¢̣ Core Antenna Complexes CP43 and CP47
Author: SHAN Ji-Xiu, YANG Kun-Yun, FENG Li-Jie, LI Liang-Bi, KUANG Ting-Yun, WANG Ju-Shuo, ZHAO Nan-Ming, LIU Yu-Long, ZHU Ke and YANG Guo-Zhen
Journal of Integrative Plant Biology 1999 41(3)
      
    PS ¢̣core antenna complexes, CP43 and CP47, were purified from spinach (Spinacia oleracea L. ) by DEAE-Fractogel rISK 650S anion-exchange chromatography. Their normal temperature (298 K) resonance Raman spectra were measured. The results suggest that all ¦Â-carotenoids bound to CP43 and CP47 are in all-trans configuration and likely in twisted conformations.
Abstract (Browse 1967)  |  Full Text PDF       
The Chemical Constituents in the Stem of Goniothalamus griffithii
Author: CHEN Si-Bao and YU Jing-Guang
Journal of Integrative Plant Biology 1999 41(3)
      
    Twelve compounds were isolated from the stem of Goniothalamus griffithii Hook f. et Thorns. Seven of them were identified as styryllactones: goniothalamin (1), 9-deoxygoniopypyrone (2), altholactone (3), goniodiol (4), goniotharvensin (5), goniofufurone (6) and 8-acetylgoniotriol (7). The other five compounds were identified as squamolone (8), pinocembrin (9), succinic acid (10), ¦Â-sitosterol (11) and stigmasterol (12) on the basis of spectral analysis (IR, MS, NMR and 2D-NMR). Among them, compounds 1, 2, 3, 5, 6, 7, 8, 9 and 10 were identified from this plant for the first time.
Abstract (Browse 1807)  |  Full Text PDF       
 

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