Mustard Insect Resistance And Resistance Mechanism Research

The interaction of plants and herbivores is an active field in evolutionary ecology. The role of sequestered plant defence chemicals (allelochemicals) on herbivore susceptibility has been explored in several studies. Glucosinolates (GS) are known to act as feeding deterrents or to have directly toxic effects on insect herbivores, and insect herbivores have the ability to detoxify or sequester defensive compounds from their host plant.In order to demonstrate the effects of mustard cultivars (Brassica juncea Linne) (Yongzha4?Yongzha2?Potherb mustard) on plant-herbivores interactions, the following questions are addressed:(1) Effects of mustard cultivars on egg numbers and development characteristics of the beet armyworm (Spodoptera exigua (Hubner)) and the Small White (Pieris rapae Linne). (2) Effect of the induced plant resistance treated by herbivory damage on body weight and detoxification enzyme of S.exigua. (3) Effect of the induced plant resistance treated by herbivory damage on body weight and detoxification enzyme of P. rapae. This study has significant importance to screening high quality of cruciferous vegetables and to defense the herbivores insects. The results showed as follows:1?GS content of different mustard cultivar is Yongzha4 > Yongzha2> Potherb. The oviposition choices of S. exigua and P. rapae have no significant correlation with GS content. The development duration and pupal stage of S. exigua feeding potherb are longest, the pupa weight is minimum,the longevity of the adult is shortest; the development duration and pupal stage of P. rapae feeding Yongzha4 are longest, pupa weight is minimum, the longevity of the adult is shortest. The result shows that the growth and development has been inhibited.2?After the induced plant resistance treated by herbivory damage, the body weight of S. exigua larval grow slowly,the body weight has a significantly reduce when feeding at 48 h and 72 h between feeding induction and direct feeding. The TI activitie of S. exigua is highest at 48 h by direct feeding and has no significant difference at different times by feeding induction. The GSTs activity of S.exigua larval showed significant increases after direct feeding 48 h and feeding 48 h after induction.3?The body weight of P. rapae larval grow faster by induction, and has a significantly growth when feeding at 72 h between feeding induction and direct feeding. The TI activity of P. rapae has no significant difference at different times by different treatments. There had no significant difference on GSTs activity of P. rapae at different times by direct feeding. The GSTs activity of P. rapae larval showed significant increases after feeding 48 h and 72 h after induction.