南美斑潜蝇为害对黄瓜体内主要营养物质、 次生代谢物质及叶绿素含量的影响

南美斑潜蝇Liriomyza huidobrensis (Blanchard)是一种危害多种蔬菜和观赏植物的多食性害虫。本研究采用蒽酮比色法、 考马斯亮蓝法、 磷钼酸 磷钨酸比色法、 索氏回流法及丙酮法， 分别测定了南美斑潜蝇1~3龄幼虫不同为害程度（系统受害、 轻度受害和重度受害）对黄瓜叶片内可溶性糖、 可溶性蛋白质、 单宁、 黄酮及叶绿素含量的影响。结果表明： 南美斑潜蝇幼虫为害后， 黄瓜叶片中可溶性糖、 可溶性蛋白质和叶绿素的含量随着为害程度的增强而显著降低（P<0.01）， 最大降幅分别为62%， 35%和40%； 单宁和黄酮的含量随着为害程度的增强而显著上升（P<0.01）， 最高升幅分别为26%和53%； 并且具有系统性影响。结果提示， 南美斑潜蝇幼虫为害导致寄主植物营养物质含量下降、 光合作用降低， 而次生代谢物质含量上升， 从而对植食者产生诱导抗性。本研究结果为进一步揭示南美斑潜蝇与其寄主植物相互作用关系及其机理提供了有益的参考。

Effects of infestation of Liriomyza huidobrensis (Diptera: Agromyzidae) on the contents of main nutrients, secondary metabolites and chlorophyll in cucumber leaves

The pea leafminer, Liriomyza huidobrensis (Blanchard), is a polyphagous insect pest on vegetables and ornamental plants. In order to investigate the interaction between this pest and its host plants, we assayed the contents of soluble sugars, soluble proteins, tannins, flavones and chlorophyll in cucumber leaves infested by the 1st to 3rd larvae of L. huidobrensis with different damage levels using anthrone colorimetric method, Coomassie brilliant blue staining, phosphor-molybdenum acid-phosphor-tungstenic acid colorimetry, Soxhlet extraction and acetone spectrophotometry, respectively. The results showed that the contents of soluble sugars, soluble proteins and chlorophyll in cucumber leaves decreased while those of tannins and flavones increased with the increase of damage by the larvae. The largest decrease amplitudes of the former three were 62%, 35% and 40%, respectively, and the highest increase amplitudes of the latter two were 26% and 53%, respectively. The influences of the larval infestation on the above compounds were systemic. The results suggest that the larval damage caused the decrease of nutrient contents and phytosynthesis of host plants while the increase of secondary metabolite contents, and therefore induced the resistance to herbivores. This study may provide a useful reference to further research on the interactive mechanisms between the leafminer and its host plants.