稗叶枯菌及其毒素的研究——Ⅱ.病菌寄主范围和对稗的致病性

病原菌孢子悬浮液经人工接种可侵染稗、高梁、玉米和大麦,但不侵染水稻、小麦和小米.病菌的培养滤液稀释液对稗、高粱、小米表现毒性,对水稻、小麦、玉米、大麦不表现毒性.用培养滤液配成的孢子悬浮液接种2叶期稗苗.10d 后最高死苗率为60.5%,病情指数为86.63.     

Fluazifop-butyl causes membrane peroxidation in the herbicide-susceptible broad leaf weed bristly starbur (Acanthospermum hispidum)

In order to clarify the action mechanism of fluazifop-butyl, an aryloxyphenoxypropionate (AOPP) herbicide in bristly starbur (Acanthospermum hispidum DC.), a unique fluazifop-butyl-susceptible broad-leaved weed, ethylene evolution and membrane lipid peroxidation in the plant seedlings were investigated. Foliar application of fluazifop-P-butyl induced ethylene evolution only from bristly starbur, but not from oat (Avena sativa L.), another fluazifop-butyl-susceptible species, and two tolerant species, pea (Pisum sativum L.) and hairy beggarticks (Bidens pilosa L.). The other AOPP herbicides, quizalofop-ethyl and fenoxaprop-ethyl, and a cyclohexanedione (CHD) herbicide, sethoxydim, did not enhance ethylene production from bristly starbur. This fluazifop-butyl-induced ethylene production in bristly starbur was completely suppressed by aminoethoxyvinylglycine (AVG), a 1-aminocyclopropane-1-carboxylic acid (ACC) synthase inhibitor, but not by p-chlorophenoxyisobutyric acid (PCIB), an anti-auxin compound, suggesting this evolved ethylene was not auxin-induced. Phytotoxic action by fluazifop-P-butyl (5 μM) in bristly starbur was reduced markedly by two lipid-soluble antioxidants, vitamin E, and ethoxyquin. The ethylene production from the plant was also inhibited by these two antioxidants. Content of malondialdehyde, an indicator of lipid peroxidation, increased only by fluazifop-P-butyl in bristly starbur seedlings but not in oat, and this increase was inhibited by ethoxyquin. These results strongly suggest that the primary site of action for fluazifop-butyl in bristly starbur is on the membranes and active oxygen species and/or free radicals are involved in peroxidation. Ethylene evolution is probably induced by these reactive oxygen species.     

群体遗传惯性理论与选择极限 续

2 群体遗传惯性与选择极限的理论分析根据群体遗传惯性理论,我们可以把外部力量(主要是选择)对群体的作用力称为选择压(Se-lection Pression,Sp),由这种选择压的作用而引起群体期望能获得的遗传反应称为期望选择反应(Expected Selection Respones,ER),或者简称选择反应(Selection Respones,R)。而把群体实际所获得的遗传值的变化定义为遗传增量(GeneticGain,△G),或称为获得遗传反应(Observed Se-lection Respones,OR)。这样我们就把群体的实际遗传增量定义为选择反应与群体遗传惯性力之差,即:     

THE URBAN PLANNING OF THE RESERVIOR AREA OF THREE GORGES ALONG THE YANGTZE RIVER

Looking back on the urban planning of the reeervior area of three sorges alonsthe Yangtze River and integrating with the development of the theory of urban planning and the reqirements of building the reservior area ,ten principles of planning and reconstruction are put for-warded .     

藕炭疽病病原及生物学特性

 该病为国内首次报道,在南宁、贵港等市县近年来有日趋严重之势。4~5月见病,夏秋时节病重,病叶率达70%以上。     

水产品在我国膳食中的地位和作用

本文从我国水产品生产地区分布上不平衡的特点出发,结合畜禽产品和国外情况,重点分析考察了沿海渔业区、淡水渔业区和山地高原非渔业区水产品在膳食中可能提供的动物蛋白质数量水平及其地位作用。着重指出了人口为全国30%的沿海渔业区占有全国73%的水产品,而人口为70%的淡水渔业区和非渔业区只占有全国水产品的27%。因而尽管1989年全国水产品蛋白质人均占有量仅为3.1克/人日,但沿海渔区却达到相当于世界多数渔业国的7.4克/人日的平均数量水平,并在动物蛋白质中占有平均40%的高比例水平,对保证膳食营养具有重要作用。在人口为40%的淡水渔业区蛋白质的平均占有量为2.0克/人日,在动物蛋白质中只占16.6%,但在淡水生产较快发展的前景下,90年代末仍有可能提高到现有全国平均水平3.1克/人日,部分省区有接近现有沿海渔业区水平的可能。但占有30%人口的非渔业区水产品蛋白质平均占有量仅为0.3克/人日,在提高膳食中动物蛋白质的作用上,不具有任何实质意义。     

辣椒黄绿苗突变体的选育及遗传分析

磁带 椒黄绿苗突变体是辣椒叶色隐性突变体。该突变体黄绿色遗传性状稳定，苗期遗传标记性状明显，抗苗期疫病等，在杂交育种及品种纯度鉴定上有极大的利用价值。     

马铃薯脱毒小薯密度试验及其田间实用性探讨

本文研究了马铃薯脱毒小薯５个不同粒度水平和３个密度水平下的生产能力和种薯的投入产出情况．通过试验，分析和比较了不同处理的主要经济性状的表现．综合评价了不同处理的利用价值，筛选了可用于生产的较好的粒度和密度水平。试验结果表明：０．５～１０．ｇ的脱毒小薯是田间生产较好的粒度水平，合理的种植密度为９０００株／亩。     

光耦合线性放大器

本文介绍了一种采用光耦合器和运算放大器组成的光耦合线性隔离放大器线路,对线路的工作原理和误差进行了定量分析。它具有线性度好、隔离电压高、频带宽等特点,可用于需要将信号放大,并在输入和输出之间进行电气隔离的地方。如漏电流将危及人身安全的医用仪器,过程控制中的计算机和外部设备的接口中。后者因现场干扰使计算机不能正常工作。