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971.
值此中华人民共和国成立三十六周年之际,迎来了《昆虫学报》创刊三十五周年。这是一件值得祝贺的事。自从党的十一届三中全会以来,我国形势有了巨大进展。十二届三中全会又作出了关于经济体制改革的决定,鼓舞了全国人民的雄心壮志。展现在我们面前的政通人和,一派兴旺发达的景象,无论在工农业生产和各条战线都取得了伟大成就。科学工作在此大好形势下,蒸蒸日 相似文献
972.
G. W. KOCH E.-D. SCHULZE F. PERCIVAL H. A. MOONEY C. CHU 《Plant, cell & environment》1988,11(8):755-767
Abstract. Wild radish plants deprived of, and continuously supplied with solution NO?3 for 7 d following 3 weeks growth at high NO?3 supply were compared in terms of changes in dry weight, leaf area, photosynthesis and the partitioning of carbon and nitrogen (NH2-N and NO?3-N) among individual organs. Initial levels of NO?3-N accounted for 25% of total plant N. Following termination of NO?3 supply, whole plant dry weight growth was not significantly reduced for 3 d, during which time plant NH2-N concentration declined by about 25% relative to NO?3-supplied plants, and endogenous NO?3-N content was reduced to nearly zero. Older leaves lost NO?3 and NH2-N, and roots and young leaves gained NH2-N in response to N stress. Relative growth rate declined due both to decreased net assimilation rate and a decrease in leaf area ratio. A rapid increase in specific leaf weight was indicative of a greater sensitivity to N stress of leaf expansion compared to carbon gain. In response to N stress, photosynthesis per unit leaf area was more severely inhibited in older leaves, whereas weight-based rates were equally inhibited among all leaf ages. Net photosynthesis was strongly correlated with leaf NH2-N concentration, and the relationship was not significantly different for leaves of NO3?-supplied compared to NO?3-deprived plants. Simulations of the time course of NO?3 depletion for plants of various NH2-N and NO?3 compositions and relative growth rates indicated that environmental conditions may influence the importance of NO?3 accumulation as a buffer against fluctuations in the N supply to demand ratio. 相似文献
973.
本文记述钩蛾亚科距钩蛾属13种,内有3亚种,包括4新种及1新亚种,此记录已超过前人记载。为节省学报篇幅,旧种记述略去,新种亦只扼要记述。详细记述将来另行发表。模式标本存于动物研究所。 中国的钩蛾科只有两亚科,其中山钩蛾亚科已整理发表,钩蛾亚科将陆续发表。本科与圆钩蛾科(已发表)的地理分布最为奇特,绝大多数种类为中国产。研究其发源地及扩展方向,颇饶兴趣。 相似文献
974.
Detection of lettuce necrotic yellows virus by an enzyme-linked immunosorbent assay in plant hosts and the insect vector 总被引:1,自引:0,他引:1
An enzyme-linked immunosorbent assay (ELISA) system for the rapid detection of the plant rhabdovirus, lettuce necrotic yellows virus (LNYV) in plant hosts and individual aphid vector is described. The method has been shown to be reliable and sensitive, and to have a number of advantages over the conventional methods of detecting LNYV in plants and insects by infectivity tests. 相似文献
975.
The addition of pollen to spores of Botrytis cinerea Fr. in droplets of distilled water stimulates spore germination, growth of germ tubes and lesion development. Aqueous diffusate from pollen is as effective as pollen grains, and frozen pollen is more stimulatory than freshly collected pollen. The presence of pollen grains reduces considerably the number of spores needed to allow infection to occur. The lost germination ability and infectivity of old spores is restored by pollen. The stimulatory effect of the presence of pollen has been demonstrated both in vitro and on the surfaces of strawberry petals, strawberry fruits and broad bean leaves. Complete removal of the source of pollen, the anthers from strawberry fruits, markedly affected the speed and severity of infections of strawberry fruits. On broad bean leaves the addition of pollen grains to spores induced the development of spreading aggressive lesions. Preliminary work indicates that the effective principle in pollen is water-soluble, dialysable and heat-stable. Although glucose and fructose are important components of diffusate, neither glucose solution nor fructose solution nor a mixture of the two showed as marked effects as did pollen. Orange juice produces similar effects. 相似文献
976.
977.
金银花Lonicera japonica Thunb.是药用植物,在山东、浙江等省种植很广,经济价值 相似文献
978.
鲤科鱼类鲈鲤的亚种分化和分布 总被引:4,自引:0,他引:4
鲈鲤属过去只记载1种、2亚种;整理后增加一新亚种,命名为后背鲈鲤Percocypris pingi retrodorslis subsp. nov. 本新亚种主要特征是背鳍后位,吻部及口裂较宽,触须发达,体色和斑纹较淡。健游和肉食是本属分化的主要倾向。性状—功能—适应三位一体,互相联系。其性状分化表现在:背鳍起点位置,体色花纹,触须长短,比例性状的差别,前上颌骨和下颌骨的形态等。综合比较结果:不同类群因适应不同环境,而形态产生不同;再从分布图可看出在水系和地域的联合上,牠们各占一方。鲈鲤占领金沙江水系,分布面最大;后背鲈鲤占领澜沧江和怒江部分上游干支流,次于鲈鲤;花鲈鲤见于抚仙湖和南盘江的个别地方,面积最小。物种分化是适应和占领环境的结果,各占一方是物种分化的证据。 相似文献
979.
Paternal inheritance of mitochondria DNA in sheep was discovered by examination of 152 sheep from 38 hybrid families for mtDNA D-loop polymorphisms using PCR-RFLP, amplification of repeated sequence somain, and PCR-SSCP of the D-loop 5′ end region of a 253 bp fragment. Our findings have provided the first evidence of paternal inheritance of mtDNA in sheep and possible mechanisms of paternal inheritance were discussed. 相似文献
980.
硝基精氨酸抑制巨噬细胞内一氧化氮合成的研究 总被引:1,自引:0,他引:1
运用体外分离培养方法,研究硝基精氨酸(Nω-nitro-L-arginine,L-NNA)抑制巨噬细胞内诱生性一氧化氮合成.发现L-NNA能抑制一氧化氮的合成,而且在一定的范围内,其抑制作用随L-NNA作用剂量的增大而增强;在培养体系中加入L-精氨酸能够逆转这种抑制作用.说明L-NNA可能通过竞争性地与诱生型一氧化氮合成酶(iNOS)活性位点结合,抑制巨噬细胞内的一氧化氮合成. 相似文献