外源化合物诱导后小麦对麦长管蚜和粘虫的抗虫性研究

喷施外源化合物和昆虫取食均可诱导小麦的防御反应，如挥发物组成发生改变、某些次生物质含量增加或减少，进而影响昆虫和天敌的行为反应。本实验中小麦苗经茉莉酸或几丁质喷施诱导，可显著提高小麦中丁布的含量，但茉莉酸甲酯的诱导作用不明显。喷施茉莉酸及麦长管蚜或粘虫取食诱导小麦，会导致小麦挥发物的种类及含量与对照相比有显著不同，3种处理间小麦的挥发物也存在显著差异。用经茉莉酸处理的麦苗饲养麦长管蚜和粘虫，可显著抑制二者的生长发育速度，使体重减轻，并导致麦长管蚜繁殖力下降。经茉莉酸处理的麦苗的挥发物对粘虫寄生蜂有吸引作用，表明茉莉酸在诱导小麦产生直接抗虫性的同时，还能诱导其释放吸引天敌的挥发性化合物从而产生间接抗性。

Wheat resistance induced by exogenous chemicals to the wheat aphid, Sitobion avenae (F.) and the oriental armyworm, Mythimna separata (Walker)

Application of exogenous chemicals and feeding of insect pests can induce wheat to produce various defense responses, such as changing in the composition of volatiles and contents of other secondary metabolites, which in turn will affect the behavior of phytophagous insects and their natural enemies. The concentration of DIMBOA (2,4-dihydroxy-7-methoxy-1,4(2H)-benzoxazin-3-one) increased in wheat seedlings after jasmonic acid (JA) or chitin solution was sprayed, but no change of DIMBOA concentration was found in the wheat treated with methyl jasmonate. Application of JA and feeding on the wheat by the wheat aphid, Sitobion avenae (F.) and the oriental armyworm, Mythimna separata (Walker) could induce the change of volatile profiles in wheat seedlings. The volatiles emitted from JA-applied plants could attract the parasitoid, Microplitis tuberculifer Wesmael, one of the natural enemies of the oriental armyworm. Furthermore, when they were feeding on the wheat sprayed with JA, the development and weight of the wheat aphids and oriental armyworms were restrained significantly, and the fecundity of the wheat aphids decreased significantly. The results indicated that application of JA in wheat seedlings can induce wheat to produce both direct defenses and indirect defenses by emitting specific blends of volatiles that attract natural enemies.