几种楝科植物种核油对褐稻虱的拒食作用试验

某些楝科种核油对褐稻虱具有特殊的作用,它与常规的化学杀虫剂不同,并不直接杀死害虫,而是引起褐稻虱对使用种核油的水稻产生拒食或避忌,对褐稻虱重要天敌蜘蛛类并不伤害。     

武昌东湖软体动物的生态分布及种群密度

本文报道1963年4—5月和10—11月两度在东湖101个采样点上进行软体动物定量采集的结果。软体动物计41种,隶10科、20属,其中腹足类的种类多,生物量也大,瓣鳃类则全系小型种类主要为河蚬(Corbicula fluminea),个体数及生物量都很低。根据10—11月的调查结果,全湖软体动物平均生物量为30.5克/平方米(平均个体数为134个/平方米),其中以铜锈环稜螺(Bellamya aerginosa)生物量最大(15.5克),其次为纹沼螺(Parafossarudus striatulus)(5.8克)和长角涵螺(Alocinma longicornis)(6.4克),这3种腹足类占全部软体动物生物量的90%以上,是东湖中的优势种类。它们的分布型式属大小不等的核心分布,其实际分布概率,符合P-E 分布的理论概率。环境分析表明铜锈环稜螺的分布主要取决于水深(r=-0.257;d.f.=99;p0.01);长角涵螺数量的多寡受制于水草的有无(均数比较:d.f.=99时,t′=7.656;t0.01≈2.641);而纹沼螺的分布则与水深有关(r=-0.697;d.f.=99;p0.01),又与水草的有无有关(平均数比较:d.f.=99时,t′=6.93;t0.01≈2.641)。       

昆虫保幼激素类似物对棉蚜形态和不育的效应

认识昆虫保幼激素对昆虫生长发育所起的调节作用已有较长时期,而探索用人工合成昆虫保幼激素类似物防治害虫还是近一、二十年的事。近年来,一些试验结果证明ZR-777等对蚜虫有很高的生理活性;Nassar(1973),Tamaki(1973),Benskin(1973),Kubr(1973)及广东农林学院(1976)等都有报道,但对不育类型,不育个体的不育程度与寿命,尤其是对胚胎发育影响,尚未见系统报道。本文比较系统地讨论这一问题。在室内和田间试验基础上,还初步提出该类化合物对蚜虫活性测定程序和鉴定指标。     

土生空球菌及其在火炬松上形成的菌根

土生空球菌(cenococcum geophilum)是一种寄主范围最广、研究最多的外生菌根真菌。本文首次报道了该菌在中国的发现及该菌与火炬松所形成的菌根,全面描述了该菌根的形态学和组织学特征,并对该菌进行了分离培养,描述该菌在纯培养下的特征,对该菌在火炬松上形成的菌根的特征进行了比较,同时讨论了该菌在造林中的重要性。     

蛋白质组学技术及其在生物医学上的应用

蛋白质组学部分承用了创立于二十多年前的二维电泳技术。基于其高分辩能力 ,二维电泳主要用于分离和检测复杂混合物中的蛋白质。虽然没有获得更多的改进 ,但是二维电泳结合了通过质谱测定蛋白质的最新进展而成为蛋白质组学中的一项重要技术。随着人类基因组计划项目的完成及由此而产生的大量基因数据库和使用这些数据的生物信息技术 ,科学家们的下一个目标是解析生物体的完整蛋白质组 ,把蛋白质组学数据与基因组学数据关联起来并有机地结合而成为一项有力的工具以阐明病理学中的蛋白质功能、衰老的过程及发现新药目标蛋白质和疾病标识物等。文章综述了蛋白质组学技术的最新知识及其在生物医学研究中的潜在应用     

黑粉菌属的聚类分析

本文对我国黑粉菌属(Ustilago)51个样本,选取33个形态学和生物学编码性状进行了类平均法的系统聚类分析。根据聚类分析结果,建议将我国黑粉菌属分为3个表观群(Phenons);茭白黑粉菌目前以放在黑粉菌属内为妥;还认为 Ustilago ocrearum 是 Ustilagokoenigiae 的变种;Ustilago kusanoi 是 Ustilago minima 的变种;Us(?)ilago aoenoe 和 Usti-lago nuda 是两个不同种。     

BIOLOGICAL ACTIVITY OF EXTRACT OF STELLERA CHAMAEJASME AGAINST FIVE PEST INSECTS

Abstract Biological activity of an extract of the root of Stellera chameajasme with ethanol by dip (SCEE) against 5 insect pests, Pieris rapae, Plutella xylostella, Spodoptera litura, Myzus persicae , and Ostrina fumalis as tested. The LD, of stomach poison of SCEE against the fifth instar larvae of P. rapae was 12. 32 μarvae day 2 after treatment. With SCEE at concentration of 5, 2. 5 and 50 mg/mL, the fifth instar larvae of P. rapae , the third instar larvae of P. xylostella , and the third instar larvae of S. litura by disc leaf dipped method, had corrected mortalities of 100%, 31. 03 % and 16. 67 % 7 days after treatment respectively. The LC₅₀ of SCEE against M. persicae was 0. 599 2 mg/mL after day 2 treatment by leaf dipped method. With SCEE at 10 mg/mL for the third instar larvae of O. furnucalis by mixture pesticide method, the corrected mortalities of 65. 52% and 85. 72% days 7 and day 14 after treatments respectively. The results showed that SCEE possessed strong biological activity to P. rapae, O. furnacalis , and M. persicae , while possessed weak biological activity to S. litura and P. xylostella .     

THE DIET, PREY SIZE AND CONSUMPTION OF PHILINE ORIENTALIS (OPISTHOBRANCHIA: PHILINIDAE) IN HONG KONG

Philine orientalis occurs on Hong Kong's beaches for {smalltilde}2 months each year, in May and June when it breeds, laysegg capsules and dies. It is believed to have a life span ofone year. Hoi Sing Wan, a sandy beach in the New Territoriesof Hong Kong is dominated at lower levels by the venerid bivalveTapes philippinarum, the population of which in May and June,following spring recruitment, mostly comprises juveniles. P.orientalis, occurring at a density of {small tilde} 1.m^–2,feeds voraciously upon these juveniles consuming, in laboratoryexperiments, a mean of 25.day^–1. At Hoi Sing Wan, P. orientalisappears to be highly prey specific. It is, however, known tofeed on other prey items and probably has a catholic diet, duringits annual migration from deeper to shallower sediments, accordingto the prevailing fauna. In terms of wet weight, P. orientalis consumes a mean of {smalltilde}4.4% (2.2–6.7%) of its body weight day^–1.In terms of dry weight, however, this figure increases to amean of 35.5% and one figure of 208% has been recorded. Althoughthis is because of the large body fluid content of this, essentiallyshell-less, gastropod, using a hydrostatic skeleton to achieveburrowing, such figures further attest to the voracity of thebreeding adults. This study joins others in questioning ourpresent understanding of the scale of energy budgets on suchshores, i.e., are our estimates of loss to predation grosslyunderestimated? ^*Present address: Department of Biology, Baptist College, WaterlooRoad, Kowloon, Hong Kong. (Received 20 May 1989; accepted 3 July 1989)     

Differential Responses of Buds along the Shoot to Factors Involved in Apical Dominance

Intact and decapitated 6-node shoots of Hygrophila sp. weregrown aseptically immersed in liquid half-strength Knop's solutionwith microelements and 2% (w/v) sucrose (control medium), andin medium with 0.1 mg l^–1 benzyladenine (BA). In intactshoots grown in control medium apical dominance suppressed outgrowthof the lateral buds; in decapitated shoots buds grew out atseveral of the most apical nodes, increasing in size acropetally.There was a lag in outgrowth of the bud at the most apical node,attributable to its initially smaller size. Lateral shoots grewout first at basal nodes of intact shoots in BA medium, decreasingin size acropetally; in decapitated shoots in BA medium lateralshoots of approximately equal size grew out at all nodes. Differentialeffects of decapitation and cytokinin treatment on lateral shootoutgrowth along the shoot could be interpreted by postulatinga basipetally decreasing gradient of endogenous auxin concentrationin the intact shoot. Application of 20 mg l^–1 indoleaceticacid (IAA) in agar to decapitated shoots completely preventedbud outgrowth for at least 7 d in control medium, inhibitingit thereafter, and inhibited bud outgrowth in BA medium, thussupporting the hypothesis. Comparison of lateral shoot outgrowthin whole decapitated shoots and severed decapitated shoots (isolatednodes) lent no support to the alternative hypothesis that theremight be an acropetally decreasing concentration gradient ofa bud-promoting substance in the intact shoot, and demonstratedmuch greater lateral shoot growth in isolated nodes. The resultsemphasize important correlative relationships between the partsof a shoot with several nodes.