土壤不同肥力对黄瓜体内可溶性有机物组成及棕榈蓟马发生的影响

The Effects of Different Soil Fertility on Composition of Soluble Organics of Cucumber and Occurrence of Thrips palmi

土壤肥力影响作物的各项生理指标,也会影响在作物上栖息取食昆虫的生长发育,最终影响昆虫种群发展.为了评价不同土壤肥力对棕榈蓟马种群数量的影响,本文研究了施用氮、磷、钾3种肥料3种水平下黄瓜叶片可溶性有机物(还原糖、可溶性总糖、可溶性蛋白质、脂类、游离氨基酸、类黄酮、总酚)质量分数,采用五点取样法调查了棕榈蓟马虫口数量的差异.研究结果表明,氮肥和磷肥施用剂量增加均可使黄瓜叶片内游离氨基酸质量分数显著上升,钾肥施用剂量增加则不能达到这样的效果;氮肥施用剂量增加引起顶叶上棕榈蓟马成虫数量和落卵量显著增加,其与黄瓜顶叶中的游离氨基酸质量分数上升呈高度正相关;中叶上若虫数量增加与中叶中游离氨基酸质量分数上升呈高度正相关.磷肥施用剂量增加引起顶叶成虫数量显著增加,落卵量和中叶若虫数量均呈先上升后下降趋势;顶叶中游离氨基酸质量分数与顶叶上成虫数量呈中度正相关;钾肥施用剂量增加仅引起顶叶成虫数量显著增加,落卵量和中叶若虫数量变动不显著.施用氮肥、磷肥和钾肥对植株顶叶类黄酮和总酚质量分数都没有显著影响.以上结果说明,施用氮肥和磷肥引起的叶片内游离氨基酸质量分数增加是促进棕榈蓟马虫口数量上升的重要因素,游离氨基酸质量分数也是判断黄瓜是否具有抗虫性的重要因子,总酚和类黄酮没有起到抗虫作用.

Soil fertility affects not only the physiological indexes of crops,but also the growth and development of insects that inhibit and feed on crops,and finally affects the development of insect populations.To evaluate the effects of different soil fertility on Thrips palmi population,the contents of soluble organic matter(reducing sugar,total soluble sugar,soluble protein,lipids,free amino acids,flavonoids and total phenols)in cucumber leaves were studied under three levels of nitrogen,phosphorus and potassium fertilizers applications.Five-point sampling method was used to investigate the differences in the number of Thrips palmi.The results showed that the content of free amino acids in cucumber leavessignificantly increased with the increasing doses of nitrogen and phosphorus fertilizer,but did not increase with increasing doses of potassium fertilizer.Increase of nitrogen fertilizer significantly increased the number of adult thrips and eggs on the epical leaves,which was highly positively correlated with the increase of free amino acid content in epical leaf of cucumber.There was a high positive correlation between the number of nymphs on the middle leaf and the content of free amino acids in the middle leaf.The number of adults on epical leaf increased significantly with the increase of the dose of P fertilizer,and the number of eggs on epical leaf and nymphs feeding on middle leaf increased first and then decreased.The content of free amino acids in the parietal leaf was moderately positively correlated with the number of adults on the epical leaf.The increase of potassium fertilizer dose only caused a significant increase in the number of adults on the epical leaf,but no significant changes in the number of eggs laid on the epical leaf and nymphs on the middle leaf.The contents of flavonoids and total phenols in epical leaf were not significantly affected by the application of N,P and K fertilizer.These results indicated that the increase of free amino acid content in leaves caused by nitrogen and phosphorus fertilizer application was an important factor promoting the increase of the number of T.palmi.The content of free amino acid is also an important factor to determine whether cucumber has insect resistance.Total phenols and flavonoids had no effect on insect resistance.