Abstract:Experiments showed that the nuaber of pods borne by the individual yardtong bean plant was an important agronomic character determining its output,and the weight of the pods borne on the main vine of the yard long bean accounted for 70-90 per cent of the total output of the whole plant;the other 10-30 per cent coming from the lateral vines.Moreover,the weight of the pod flesh constituted over 80 per cent of the weight of the pod.Analyses showed that the length of the pod decide determined its protein content level.The longer the pod,the higher the protein level.That the heritability of the pod length in the broad sense came up to as 93.6 per cent showed that it was not easily influenced by environmental cinditions but easy to fix in progenies,easy to measure with the eye and favourable to seed selection.Therefore,when yardtong bean seeds are to be selected for breeding,atten-tion must be paid to select pods from individual plants or plant lines which are able to bear more and longer pods with thick flesh to provide seeds for propagating progenies,and so as to raise the output and protein content of the pod and to facilitate the breeding of new varieties with high yield and superior quality.

Abstract:The cellulase A(buffer-soluble)and B(salt-soluble)activities in abseission zone of fruit explants of "Anliu-cheng" orange(Citrus sinensis Osbeck)rose markedly during prenalure drop just after petal fall(first fruit drop),cellulase A activity in the abscission layers of fruit explant and attached fruit also increased significantly in the course of the shedding at the disc(second fruit drop),but there was little change in rellulase B during that time.2,4-D could inhibit not only the abscission of fruit explants collected in the two fruit drops just mentioned above,but also first fruit drop in the field by low concentration spraying,due to the marked depression of the exo-and endo cellular cellulase,cellulase A activity and ethylene production.But it had no significant effect on cellulase B activity in this experiment.The use of gibberellic acid in decreasing fruit shedding during the second drop was more effective than that of 2,4-D.The relationships among fruit abscission,cellulaseactivity and ethylene production and the regulating mechanism of 2,4-D on fruit drop were discussed.

Abstract:Seventy seven current cultivars,including early-crop and late-crop types,were subjected to 15 treatments of natural and artificial daytength ranging through 8.0,10.0,10.5,11.0,11.5,12.0,12.5,13.0,13.5,14.0,15.0,18.0,21.0,24.0 hours for 17 seasons within 8 years in 1980-1987.Data were treated statistically by means of the computer.Thus,according to their photoperiod qualities,the current rice cultivars could be divided into 4 types:insensitive type,weakly sensitive type,strongly sensitive type,extremely sensitive type;and considering day length and temperature together,could be divided into 4 types too.1.the dayltength sensitive and temperature weakly to moderately sensitive type,2.the day length weakly sensitive and temperature moderately sensitive type,3.the daylength strongly sensitive and temperature moderately sensitive type,4.the daylength extremely sensitive and temperature moderately to strongly sensitive type.In addition,regression equations of the representative type cultivars were established.The daylength extremely sensitive type had a strictly critical daylength.With increased leafage,the daylength strongly sensitive type became less stringent in its heading daylength.

Abstract:本文研究氮、钾肥配施对赤红壤上甜玉米生长的影响,于1986年秋作和1987年春作进行两次盆栽试验及植株和土壤的化学分析。结果表明:氮、钾肥配施可增加供试土壤有效氮和速效钾含量,可增加甜玉米穗叶(吐丝明)含N量和含K量,降低穗叶含P量、含Ca量和含mg量。不施钾肥处理的甜玉米穗叶含K量≤1.30％,吐丝前有明显的缺K症。施高量钾肥(0.33克KCl/公斤土)处理的穗叶含Mg量≤0.15％;吐丝后出现明显的缺Mg症;施K_1水平(0.17克KCl/公斤土)的钾肥较适宜。单施氮肥处理,甜玉米果穗和籽粒的产量随施氮量增加而显著降低。配施钾肥处理,甜玉米增产率随施氮量增加而增大。增施氮肥可明显增加籽粒粗蛋白质含量,降低水溶性糖含量。施钾肥与不施钾肥比可明显增加水溶性糖含量,增加粗蛋白质总量(克/盆),但降低租旦白质含量。在供试赤红壤盆栽甜玉米条件下,氮钾肥配施以N_2K_1处理为宜

Abstract:作者根据广东省江门市某鸡场以破行鸡为主的鸡病流行情况,临床症状及病理变化等,作出鸡病毒性关节炎的假定性诊断。 从病鸡的关节滑液中分离到一种病毒,该病毒能在鸡胚卵黄囊内、尿囊腔内和绒毛尿囊膜上生长并致死鸡胚,使鸡胚皮肤呈暗红色。病毒也能在鸡胚肾细胞、鸡胚成纤维细胞上生长并引起细胞病变。病毒对鸡红细胞无凝集作用,用含病毒的鸡胚尿囊液接种敏感鸡后,可复制出与临床所见相类似的疾病。 在电镜下观察,病毒直径为63～74nm,在感染的鸡胚绒毛尿囊膜上可见到胞浆内的包涵体,经测定,病毒含有双股RNA,对氯仿、乙醚、60~0C1小时有抵抗力,对胰酶敏感。 实验结果表明:被分离到的病毒为传染性关节炎病毒,因此江门市某鸡场所发生的以跛行为主要特征的疾病可以确诊为鸡病毒性关节炎。

Abstract:Genetic variants of six blood protein Barkers including plasma amylase(Amy-1 ang Amy-2),alkaline phosphatase(Akp-1 and Akp-2),esterase(Es-1)and hemo-globin(Hb)in Xinghua,Huiyang and Qingyuan chickens,the local breeds of Guangdong,China,were determined by Beans of polyacrytamide get electrophor-esis and cellulose acetate electrophoresls.Phenotypes distribution,gene frequencies,sinitarity coefficients,genetic distances and diversification time for these breeds were calculated.Using systemic cluster analysis,Fuzzy cluster analysis,Tocher cluster analysis and principal component analysis,the relationships among these Guangdong local chicken breeds were studied.The results showed much similarity among these three breeds,and some specific features in phenotype distribution and gene frequencies for every breed were found;and there were close relationships between them,the closest relationship being between Xinghua and Qingyuan chickens.

Abstract:The paper reports study on the mechanical properties,hardening depth and microscopic structure of riding tractor central transmission axle subjected to different thermal treatments.The test revealed that the torsional and bending strength of the axle could be raised,without change in material or size when the final thermal treatment of the axle was converted from high-frequency induction hardening to medium-frequency induction hardening,with the result that the axle was able to meet the requirements of 20% increase in engine power.

Abstract:Resistance of rice to Pyricularia oryzae Cav.was considered in relation to environmental factors,such as temperature and humidity,which caused resistance changes by affecting host predisposition or by affecting infection and development of pathogenic fungus.Rice resistance to blast disease was associated with components of the rice plant.Siticification of the epidermis of rice was considered a major factor in physical resistance to blast;the degree of resistance was found to increase in proportion to the amount of silicon accumulated in the plants.A close correlation was found between susceptibility and bontent of soluble nitrogen or amino acids,and a rapid;browning reaction of infected tissues in resistant rice varieties was correlated with the amount of polyphenols in the plants.Further srudies showed that the rapid browning reaction of the host was a hypersensitive reaction caused by penetration of the pathogen,in which phenomenon could be observed broken cell membrane,granulated cytoplasm and disintegrated chlorplaslsin the epidermal and parenchymatous cells.These granules or particles foundin hypersensitive reactions were considered phytoalexins with which thehost arrested further growth of the invading fungus or killed it.However,resistance or pathogenicity is,in fact,a result of gene-to-gene interaction between a variety and a race.Further investigat ions on host-parasite interaction and the real roles,chemical and biological properties of those granules or particles found in rice leaf tissues infected with P.oryzae will be helpful for the perfect understanding of the resistance mechanism and functions of resistant genes in rice plant.

Abstract:In the present paper,the development status,insecticidat properties and application for control of insect pests in several crops of various chitin synthesis-inhibting insecticides including benzoylphenyl ureas and buprofezin are reviewed.The problems of their applications and the prospects for these insecticides are also discussed