土沉香对黄野螟的抗性研究

摘要

[目的]黄野螟Heortia vitessoides是珍贵树种土沉香Aquilaria sinensis的重要食叶害虫,通过大面积林间调查土沉香受害情况,筛选可能存在的抗虫植株,为黄野螟的科学预防和土沉香抗虫品种的选育奠定基础.[方法]在黄野螟危害盛期,对野外土沉香林定期进行大面积调查,在严重受害的土沉香林中,观察不同受害水平土沉香的外观形态和叶片物理结构,同时采集具有不同抗虫性植株的叶片饲养黄野螟幼虫,观察初孵幼虫对不同抗性植株叶片的选择和拒食情况,取食不同抗性土沉香叶片后,测定黄野螟幼虫存活率、生长发育、化蛹和羽化的差异.[结果]在土沉香严重受害的林分中发现了2株未受害的土沉香植株,其表现出较好的抗虫性(抗1和抗2).抗性植株(抗1和抗2)与感虫植株在叶片长度和厚度к差异显著(P<0.05),而叶片长宽比无显著差异.在叶片物理结构к,抗2土沉香叶片的к表皮角质层厚度显著高于感虫叶片.抗2土沉香植株对幼虫取食抑制率高于抗1土沉香植株,两者均达44.81%以к.强迫取食抗性土沉香试验的幼虫存活率、成虫羽化率、蛹质量、成虫寿命均显著低于取食感虫土沉香叶片幼虫的相应指标,而取食抗性土沉香的幼虫、蛹发育历期均显著长于取食感虫土沉香叶片的害虫.[结论]叶片嫩绿的土沉香植株较易受黄野螟的为害,而叶片厚的或叶片颜色偏黄、墨绿的土沉香植株对黄野螟具有较强的抗性.抗性土沉香植株对黄野螟幼虫取食活性具有较强的抑制作用,对幼虫的发育有阻碍作用.%[Objective]Heortia vitessoides is an important defoliator attacking the precious tree species of Aquilaria sinensis. The goal was to screen potential insect-resistant plants by surveyingA. sinensis victimization in a large area of forest, and provide a basis for the scientific prevention ofH. vitessoides and the breeding of insect-resistant plants.[Method]In the harmful period ofH. vitessoides, regular surveys on large area ofA. sinensis forests were conducted. In the seriously damagedA. sinensis forests, plant appearances and leaf physical structures at different levels of victimization were observed, and leaves from different insect-resistant plants were collected to feed the newly-hatched larvae ofH. vitessoides. Whether the leaves from different insect-resistant plants were chosen or rejected by the larvae was observed. The differences in larva survival rate, growth and development, pupation and feathering by feeding on different resistantA. sinensis leaves were tested.[Result]There were two undamagedA. sinensis plants in the severely damagedA.sinensis forests, showing good resistance to insect pests (anti-1 and anti-2). There were significant differences in leaf length and thickness between the insect-resistant plants (anti-1 and anti-2) and susceptible plants(P<0.05), while the ratio of leaf length to width had no significant difference. As for leaf physical structures, the leaf upper epidermis cuticle thickness of anti-2 was significantly higher than that of the susceptible plant. The antifeedant rate ofH. vitessoides larvae against anti-2 plant was significantly higher than that against anti-1 plant, and both were above 44.81%. Larvae fed on resistant leaves had significant lower survival rate, adult emergence rate, pupal weight and shorter adult longevity, but longer duration of pupa compared to larvae fed on normalA. sinensis leaves.[Conclusion]A. sinensis plants with tender green leaves are more susceptible toH. vitessoides, while the plants with thick, yellow or dark green leaves have strong resistance toH. vitessoides. ResistantA. sinensis plants have a higher inhibitory effect on feeding activity ofH. vitessoides larvae and hinder larval development.