灭多威和吡虫啉对棉苗缩合单宁含量的影响

为明确常用杀虫剂对棉花抗虫性的影响,研究了灭多威和吡虫啉营养液处理对棉苗中抗虫次生物质缩合单宁含量的影响。结果表明,25mg/L灭多威处理3叶期棉苗后第6、9、12和15天,50mg/L灭多威处理棉苗后第6天和第15天,棉叶中缩合单宁含量均显著增加,其中25mg/L灭多威处理棉苗15天,棉叶中缩合单宁的含量较对照增加74%。50mg/L吡虫啉处理棉苗后第2天,棉叶中缩合单宁含量与对照相比增加了45%,而吡虫啉的其它处理浓度和处理时间未对棉苗缩合单宁含量产生显著影响。杀虫剂对棉苗缩合单宁含量的影响与杀虫剂本身的性质密切相关,其中灭多威对棉苗缩合单宁含量影响较大,而吡虫啉影响则较小。此外,杀虫剂对棉苗缩合单宁含量的影响还具有一定的剂量效应与时间效应。

Effects of methomyl and imidacloprid on contents of condensed tannin in cotton seedlings

In order to examine the effects of commonly used pesticides on the insect resistance of cotton, the effects on the contents of condensed tannin, one of the insect resistance materials of cotton, in cotton seedlings were determined after hydroponically treatment with methomyl and imidacloprid. The 3-leaf stage cotton seedlings were treated with 25 and 50mg/L methomyl, 25 and 50mg/L of imidacloprid respectively for 15 days, at different treating time, the cotton leaves were harvested for determination of the contents of condensed tannin by vanillin assay. The results showed that the contents of condensed tannin in cotton seedlings increased significantly after treated with 25mg/L methomyl for 6, 9, 12 days and 15 days and with 50mg/L of methomyl for 6 days and 15 days, with the condensed tannin in cotton seedlings increased 74% than that in untreated control cotton seedlings. After treated with 50mg/L of imidacloprid for 2 days, the condensed tannin in cotton seedlings increased 45% than that in untreated control cotton seedlings, while the contents of condensed tannin in cotton seedlings did not show significantly differences between the other treatments of imidacloprid and the control, even no significant differences were observed at the other treating time. So, the effects on the contents of condensed tannin in cotton seedlings were closely related to the insecticides used, and methomyl application has a serious impact on contents of condensed tannins in cotton seedlings, but imidacloprid does not. The effects of the concentration of insecticides and the treating time on the contents of condensed tannin in cotton seedlings were observed.