Abstract:The avinilent and bacteriocinogenic strain Tm3 of Ralstonia solanacearum had inhibiting effect on tomato virulent strain Ttn46 and could induce hypersensitive response(HR) in tobacco plants. ItS ability to protect tomato plants from bacterial wilt was investigated in greenhouse and the results indicated that strain Tm3 had a good effect on the biological control of tomato bacterial wilt. The possible mechanisms for the protechon were both antibiosis of bacteriocin and induced resistance of hosts.

Abstract:Phytophthora isolates were obtalned from 9 species of diseased floral plants [Rosa chinensis Jacq. , Rhododendron spp. L., Cattleya bowringiana Hort., Dianthus caryophyllus L., Calceolaria crenatiflora Cav., Catharanthus roseus (L. ) G. Don, Euphorbia pulcherrima Willd. ex Klotzsch, Lilium spp. L. and Spathiphyllum pallas Hort. ] collected in Guangzhou region. On the basis of the sexual and asexual characteristics of their single-spore cultures combined with the cardinal temperatures and the eletrophoresis of their proteins patterns, they were identified as: P. citricola Sawada (on Rosa chinensis), P. citrophthora (R. E. Smith & E. H. Smith) Leonian (on Rhododendron spp. ), P. Palmivora (Butler) Butler (on Cattleya bowringiana and Dianthus caryophyllus), and P. nicotianae Breda de Haan (on Calceolaria crenatiflora, Catharanthus roseus, Euphorbia pulcherrima, Lilium spp. and Spathiphyllum pallas ).

Abstract:用生物间遗传学的毒力频率测定和联合致病性分析的方法，对广东省部分将推广稻组合的抗瘟性进行了鉴定，２１个待测杂交稻组合用１００个田间菌株进行接种，其中１４个组合的毒力频率小于２０％，表现出较好的抗性；联合致病性系数（ＰＡＧ）、联合抗病性系数（ＲＡＣ）和联合毒性系数（ＶＡＣ）分析杂交稻组合与稻瘟病菌群体间的相互作用，结果表明：５０个杂交稻组合间的两两搭配的联合抗病性系数较高、联合强毒性较低，均具有较好

Abstract:The experiments were conducted to study the changes of the growth hormones, free amino acids,nucleic acids and suger contents of peanut plants after being inoculated with M. arenaria. The results showed that the activity of cytokinin (CTK) and abscisic acid (ABA), the content of indole acetic acid(IAA) in the root and leaves of infected plants increased, and that the content of gibberellic acid (GA3) decreased. The contents of methionin(Met) in the root-knots and the healthy roots of infected Plants were 7. 83 and 6. 43 ug/g in fresh-weight respectively, while that of uninfected plants was zero.The contents of cysteine, lysine, arginin and reducing sugars in the roots of infected plants increased,while the contents of proline, threonine, total sugars and disreducing sugers decreased. The content of Pro in the leaves of uninfected plants was 106.18ug/g in fresh-weight, and that of infected plants was zero.The contents of Thr, glycine(Gly), alanin(Ala), histidine(His), Arg, RNA, total sugars, disreducing sugers and total free amino acids in the leaves of infected plants were significantly lower than those of uninfected plants, while the contents of DNA and phenylalanine(Phe) in the leaves of infected plants were bigger than those of uninfected plants. Ih the same infected plants,the contents of DNA, RNA, valine,Phe and Lys in root-knots were bigger than those of healthy roots, while the content of His of root-knot was lower.

Abstract:The resistane heredity of Ridgegourd downy mildew was studied by a diallel cross arnong six culivare. The results showed that both general companing ability and specifil companing ability were important to resistance; the heredity of resistance could be explained by the additive dominative genehcal model. The ratio of dominant gene by recessive alleles, heritability in narrow sense was 69. 63%. The least number of additive gene was 4.

Abstract:Experiments of orthogonal design were used to select the optimum artificial dieis for Pachlioptera aristolochia(Fabricius). Four factors, including leaf flour of Aristolochiae tagala, wheat germs,yeast flour, Spirulina platensis flour, sorbic acid, each at three different level, were tested by assessing larval stadium, pupation rate, mean pupal weight. There were no significant difference between the optimal diets and bo leaf of A. tagala on the larval stadium and mean pupal weight to rear P. aristolochiae. The pupation rate of optimal diets Selected was significantly higher than those of other artificial diets

Abstract:Chicken embryo fibroblasts (CEF) infected with each of five stains of infectious bursal disease virus(IBDV) and control CEF were harvested and tested at various stages post-infection. Upon Agarose gel electrophoresis, DNA extracted from IBDV-infected and control CEFs exhibited a laddering Pattern. The amount of the DNA fragments was measared with enzyme-linked immunosorbent assay (ELISA). There was a significant increase in the amount of DNA fragments in each IBDV-infected group, as compared with the control group, and the amount of DNA fragmets showed some differences among the infected groups. These results demonstrated that the five IBDV strains all could induce apoptosis, but different IBDV strains exhibited variation in the capacity to induce apoptosis; quantitative change in apoptosis was better detected with ELISA.

Abstract:应用透射电镜在鸡胸腺内观察一类ＡＰＵＤ（样）细胞，其主要特征是胞质内含有膜包小分泌颗粒，颗粒的形态、大小、数量、内部结构及电子密度等有差异，有的颗粒为中等电子密度，有的为均质状高电子密度，有的在中等电子密度中含有一高电子密度的致密核芯；在高倍放大下，有的颗粒在界膜与内含物之间有一低电子密度的晕轮，宽１０￣２０ｎｍ，根据其超微结构特征，可将这类细胞分为３型：Ⅰ型细胞的分泌颗粒呈圆形，直径１５０－３８

Abstract:The fertility inheritance and expression under the influence of different genetic background of four Photo-Thermo Sensitive Cenic Male Sterile Rice were studied .The results indicated that the fertility of W6154S, W7415S, N12S and N18S was controlled by two pair of nuclear recessive genes, but their expression and genetic mechanism were very complicated due to the great influence of various genetic background. By thoroughly analyzing the fertility segregation of F2, F3 population, the hypothesis, "incomplete dominance and dosage effect of restorer genes", was put forward and the poymorphism of fertility segregation was also discussed in this paper.

Abstract:A recurrent selection breeding procedure was designed by means of laigu genic(Tal) male sterile gene and employed to develop new wheat varieties with resistance to scab. Fu-Fan No. 17 with the gene Tal and other eight wheat varieties(lines) with resistance to scab were used to construct the base population of recurrent selection, New scab-resistant varieties Huanan T2003 and T531 were developed from the plants that were selected after one cycle of selection by pure line breeding method. The experience of developing new wheat variety with resistance to scab using recurrent selection method was briefly summarized.

Abstract:It could increase the separation degree from tillering termination to panicle initiation by transplanting young seedlings with thick space or adopting a nitrogen application system that was able to prolong the vegetative growth period of rice.On the other hand, the separation degree from tillering termination to panicle initiation could be lessened and the overlaping degree enhanced if old seedlings were transplanted, and wide space adopted; or less nitrogen applied in the early growth stage on the main field. The tillering-panicle initiation-overlapping pattem happened usually to the early maturing varieties and the tillering-panicle initiation isolation types could often be seen in the middle or late maturing varieties. Growth pattem of the later-season varieties which strongly sensitive to photoperiod was more easily regulated by the different seedling ages than that of the earlier-season varieties which insensitive to photorerioa.

Abstract:对大蒜愈伤组织诱导条件进行了优化，结果表明：采用带表皮、外植体大小为０．５ｃｍ×０．３ｃｍ×０．２ｃｍ的广州白皮大蒜蒜瓣，在ＭＳ＋３．０ｍｇ／Ｌ２，４－Ｄ＋２．２ｍｇ／ＬＩＢＡ培养基中可促使大蒜愈伤组织大量发生，广州白皮大蒜与大头蒜品种对务组织诱导无显著差异，大蒜外植体４℃低温保藏１８ｄ可降低出愈污染，但对伤组织诱导影响不大。

Abstract:A tobacco cell stain of HHDJY was selected by suspension cultare from 4 tobacco strains cultivated in South China on the level of CoQ10. By using this tobacco cell strain, the effectS of several plant growth regulation on the cell growth and content of CoQ10 were studied. The growth of the cells was greatly enhanced by 0.1 ~ 0. 2 mg/L BA and KT. 2,4-D could increase the content of CoQ10 but becampe unfavorable to cell growth when the concentration was high. IAA and NAA had no effect on cell growth and content of CoQ10. Morcover, CoQ10 crystal was obtained from suspension cells with acetone abstraction,petrolembenzine extraction and silica chromatography. The recovery of CoQ10 was 59. 2%, and the purity reached 97. 7 %.

Abstract:Experimnts of fruit bagging were conducted in close planting litchi orchard at Litchi's Extension Base of Guangdong Province from 1997 to 1998. The bags were made of cellopane paper, cotton,screen mesh, newspaper and kraft paper respectively. The results showed that the treatments with cellophane paper or cotton bags hastened coloration by 10 days as compared with unbagged fruits, and improved the quality of colouration through increasing the phenol, flavonoid and chlorophyll, and PAL activity. The treaments with newspaper and the paper bags suppresed the accumulation of anthocyanins significantly, and also inhibited PAL activity. Effect of the treatment with screen mesh bag on coloration of fruit peel was insignificant.

Abstract:The physiological changes of Yangshan chestnut (Castanea mollissia Blume) during storage were studied. Respiratory rate dropped with the the. The activity of superoxide dismutase (SOD) remained at a higher level in the preliminary phase (about 60 days after storage), and thereafter dropped,whereas the activities of peroxidase (POD), catalase (CAT) increased gradually. The electrical conductivity kept at a lower level during the preliminary phase (about 60 days after storage), and then increased.

Abstract:Based on the technique of Geographic Information System (GIS), Red Soil Resourcees (RSR)of Zhejiang province were classified to 84 types by computer-aided overlay analysis. The spots on the RSR classification map were selected asevaluation edts, and evaluation medels were established with three mathematical metheds. The qualitative ranks of RSR of the whole province were evaluated, and the evaluation methods and results were comared and analyzed.

Abstract:Combinations of TM remote sensing images of South China forest area are analyzed and com pared. The result shows that the TM453 cembination is better for the forest vegetation recognition by visu al interpretation and computer automatic classification. The TM472 color composite image is helpful to the interpretation of young growth, sparse woods and barren mountain. And on the TM472 color-composite image Chinese fir forest can be easily interpreted.

Abstract:采用组平均聚类法、模糊聚类法、主成分分析法对广东不同坡地利用地土壤养分含量的影响进行聚类分析，综合３种分类方法，可分为５大类：第１类包括鹤山茶和鹤山坡地花生；第２类包括鹤山茶园空地、林地有覆盖和无覆盖、芒果地、草地、荒坡和丰顺坡地青榄；第３类包括鹤山坡地龙眼、番薯、丰顺坡地龙眼和高明坡地荒果；第４类包括鹤山坡地龙眼，丰顺坡地茶曲江坡地花生和沙田柚；第５类包括高州坡地甘蔗、南雄坡地黄烟、银杏、三华李

Abstract:1400m2 plots in a Castanopsis carlesii forest at Luoba, Shixing county, north of Guangdong Province, were surveyed. Importance value, species diversity index (Shannon-Wiener Index), evenness index, ecological dominance of the community in relation to thent layers, i. e. tree layer, shrub layer,herbaceous layer and interlayer, were computed. Growth volume of the dominant species Castanopsis carlesii was also measured and calculated. Results showed that Shannon-Wiener Index of tree layer, shrub layer, herbaceous layer and inter-layer were 2.024 8, 2.902 1, 2.903 4 and 2.269 8 respectively;evennss index were 0.391 6, 0.549 1, 0.605 1 and 0.756 6 respectively; ecological dominance were 0.394 6, 0. 150 3, 0.217 1 and 0.241 5 respectively. This study can provide theoretical foundation for the management of Castanopsis carlesii forest.

Abstract:The present paper conducts the comparative observation on leaf venational morphology of 3genus and 5 species in Calycanthaceae. The result shows that 1st veins are moderately stout,2nd veins are much more, 1st veins conshtute brochido-camptodromous or reticulo-camptodromous pinnatoides with 2nd veins; 3rd veins are percurrent or reticulate, at the margin; veinlets are incomplete, areole has not a norm in shape and area, it is imperfect in system development.

Abstract:Weed community of paddy field in Nanhong, Hainan province, was studied by the help of fuzzy clustering analysis. With the dominance, the samples are aggregated to a tree diagram. The layers of the weed community are also discussed. The result can act as a guidance in the weed prevention.

Abstract:The planting system of Guangdong province is evaluated by using energy and emergy analysis theory. The results show that the emergy input level of planting system in Guangdong is lower than that in developed countries, Which suggest the emergy input should be increased. The focal point of emergy input is to raise the level of farming technology and increase renewable resource emergy input, especially using agricultural ecolopcal engineering technology and biotechniques.

Abstract:In this paper computer simulation method is provided for bending test on reinforced concrete beam cross section. The distribution and variation process of stress and strain can be seen on the screen while load increasing. on this basis we can study how to use the utilization of the steel strengthening property abundantly to design the ductile members of the structure.

Abstract:A new way of thinking about genetic code and homochirality, which remain the major difficulties in the field of the origin of life, is suggested. The author reasons that procodons must have been twoout-of-three triplets. They originated synchronously with the dipeptides coded thereby via polymerization of certain amino acid-tRNA-oligopeptides complexes. The polymorphism of genetic code reflecting the evolutionary track is the outcome of differentiation of the third position bases of the procodon, step by step; and that homochirality, as an unique behavior of life molecules tuming over in metabolic system,must have originated synchronously with the latter. A key role could have been played by the primitive glycogenesis-like pathway.