棉花品种的抗螨机制研究

 研究表明，苗期高抗叶螨的辽阳1号与感螨的爱字棉4-42相比可显著抑制叶螨的产卵和幼若螨的存活。辽阳1号抗生性的化学基础是苗期叶片具有较高的单宁和儿茶酚基酚的含量，但游离棉酚与其它感螨品种无显著差异。用帕拉膜取食系统中充入稀释8倍的棉花叶片匀浆液，其中加入不同浓度的次生化学物质，研究对叶螨取食行为和生物学影响表明，随着单宁和儿茶酚浓度的提高，对叶螨取食的排拒性增强，当单宁和儿茶酚的浓度分别达15.6g/L和4.6g/L时,24h将雌成螨排拒到帕拉膜边缘虫胶上的扩散率达90%;取食不同浓度单宁2d后的雌成螨在棉叶盘上产卵随浓度的增加而下降,相关关系显著。体外研究表明，单宁和香豆素对朱砂叶螨的蔗糖转化酶、淀粉转化酶和海藻糖酶的活性具有抑制作用，表明这二种物质可影响叶螨对碳水化合物的吸食利用，但儿茶酚未表现这种作用。

A Study on Resistance Mechanism in Cotton Cultivar to Tetranychus cinnabarinus

A study on resistance mechanism in cotton cultivar to the carmine spider mite, Tetranychus cinnabarinus (Boisduval) was carried out. The result revealed that the leaves of Liaoyang 1. (HR) inhibited oviposition and survival of larvae compared on Alkra 4-42 (S) at the seedling stage. This antibiotic was based on higher concentration of tannin and catechol-based phenolics within leaves. Effects of parafilm feeding system, which contains 8-fold dilution of cotton leaf homogenate as substrate by varying contents of tannin and catechol on feeding behavior and oviposition for the mite, were observed. The results showed increasing repellence to the mite with their content increases. Rate of dispersal achieved 90% when the contents of tannin and catechol were 15. 6g/L and 4. 6g/L within the substrate respectively. On the other hand, increasing tannin content may reduce the number of eggs that the female laid. Inhibitory effects of invertase, amylase and trehalase with the mite in vitro by tannin and caumarin were determined, but catechol was not. This result suggests that the former two phenolics can reduce digestive ability of carbonhy-drates for the mite.