The in vivo sensitivity of ATPases to DDT,DDE, and physical immobilization in American cockroaches

American cockroaches injected with sublethal doses of DDT (0.75 μg/roach) at 5-day intervals showed a 40% reduction in oligomycin-sensitive Mg²⁺ATPase from muscle homogenates, and a 23% reduction of Na⁺-K⁺ATPase from nerve cords. Thus, the maximum effect measured occurred with the same enzyme and tissue as determined from in vitro studies. The metabolite, DDE, used at 15 μg per roach, gave no significant change in activity of the ATPase system following injection. In contrast, high single doses of DDT (7.5 μg/roach) and 100 μg DDE and dicofol per roach caused over 30% increase in oligomycin-sensitive Mg²⁺ATPase of muscle and a 10–15% increase in Na⁺-K⁺ATPase of nerve cords measured 24 and 48 hr later. While a similar response was observed for Mg²⁺ATPase activities in cockroaches that were immobilized, the increase in enzyme activities were much greater than that caused by the pesticides.     

Differential tolerance of peas to prometryne and terbutryn

The phytotoxicity of 2,4-bis(isopropyl)-6-(methylthio)-s-triazine (prometryne) and 2-(tert-butylamino)-4-(ethylamino)-6-(methylthio)-s-triazine (terbutryn) to peas (Pisum sativum L. var. Perfection 3040) was studied. No differences were found when the herbicides were applied to the roots of intact plants in nutrient solution or directly to leaf discs. However, prometryne was much more toxic when uptake was from soil. Absorption and translocation of ¹⁴C-labeled prometryne and terbutryn showed that the majority of terbutryn accumulated in the roots, whereas prometryne was uniformly distributed between the roots and the shoot. Thin layer chromatography of extracts from prometryne-treated peas showed that only 20% of the absorbed compound was metabolized to produce one breakdown product. Extracts of terbutryn-treated plants contained three different metabolites. After 120 hr of exposure to terbutryn, about half of the absorbed herbicide was metabolized. The results show that the main factors responsible for the differential toxicity of the herbicides to peas were availability from the soil, translocation pattern and initial detoxication.     

Effect of infections with barley yellow dwarf virus and Fusarium spp. on assimilation of 14CO2 by flag leaves and translocation of photosynthates in wheat

Journal of Plant Diseases and Protection - The effects of infections of Barley yellow dwarf virus (BYDV), Fusarium culmorum and F. graminearum alone as well as double infections of BYDV and...     

银杏幼胚离体培养再生植株的研究

 以佛手银杏幼胚为外植体, 研究了不同大小幼胚在不同培养条件下, 愈伤组织和胚状体的诱导发育情况。结果表明: 大于3 mm的幼胚, 在MK +NAA 1.0 mg·L ^{- 1} +BA 1.0 mg·L ^{- 1}培养基上胚状体诱导率最高, 达到53.6% , 最多的一块愈伤组织形成多达38个胚状体。暗培养不利于胚状体的发生。在MK培养基上添加10%椰汁对胚状体的生长发育有很好的促进作用, 有34.5%生长成苗。     

葡萄自交与杂交后代香气成分的遗传研究

 利用气相色谱- 质谱- 计算机联用系统(GC-MC-CS) 对两个自交组合、1个杂交组合亲本及其后代的香气成分进行研究。结果表明: 同一组合中不同香气成分的分离情况不同, 同种香气成分在不同组合中的分离情况也不完全相同。果实香气成分的遗传主要表现为分离( 1∶1、1∶3、3∶1、15∶1) 与不分离两种方式, 发生分离的成分有些是由单基因控制的, 有些是由多基因控制的。     

低氧胁迫下黄瓜幼苗根系多胺代谢的变化

 利用外源Spd、PAO 抑制剂研究了黄瓜幼苗根系在低氧水培时的生长状况以及内源PAs、H₂O₂ 含量和PAO活性的动态变化。结果表明, 外源PAs对低氧胁迫下黄瓜幼苗根系的生长有促进作用;低氧处理后3种PAs含量都明显上升, 外源Spd和PAO抑制剂增加了根系中的PAs含量, 降低了根系中H₂O₂ 含量, 减缓了低氧伤害; PAs为低氧胁迫的应激产物, PAO为适应酶类, 其活性随PAs含量的变化而发生变化。     

蝴蝶兰组织培养中的褐化控制研究

 系统研究了吸附剂(活性炭、PVP) 与柠檬酸、半胱氨酸、谷胱甘肽、维生素C和硫代硫酸钠5种抗氧化剂对蝴蝶兰组培中褐化的影响。结果表明: 活性炭能有效控制褐化和促进生长, 但不利于分化; 谷胱甘肽控制褐化的效果虽不及活性炭, 但综合效果最佳。     

提高我国水果质量增强市场竞争力

本文分析了我国果品质量的现状、成因及提高果品质量的紧迫性.从13个方面讨论提高我国水果质量、增强市场竞争力的途径.     

蝴蝶花的组织培养和根状茎的诱导

蝴蝶花(IrisjaponicaThunb.)是鸢尾科鸢尾属的多年生常绿宿根草本植物,地下有横走的根状茎;耐荫,是良好的耐荫地被植物。试验于2003年10月至2004年5月进行。选择健康的蝴蝶花植株,取地下的根状茎,选带节的茎段作为外植体,用洗洁精溶液浸泡4～5min,采用75%乙醇60s结合0.1%HgCl212min进行灭菌。根状茎在培养基MS 6BA1.0mg·L-1 KT2.0mg·L-1 NAA0.1mg·L-1,25℃下黑暗培养,腋芽出芽率达65.4%。黑暗比光照更有利于腋芽的萌发,可能是由于蝴蝶花是阴性植物;在自然条件下其根状茎的生长和顶芽的萌发处于暗环境,离体条件下黑暗培养更符合其…