| Bemisia tabaci, Myzus persicae and Plutella xylostella, three important pests of cruciferous vegetables, are the major impact factors on the quality and yield of Brassica juncea and Brassica olracea. In this study, the effects of tuber mustard, red cabbage and two chimeras between them on the biological characteristics of these three herbivorous insects were investigated, and the impacts from both the morphological characteristics and secondary metabolites content of the chimeras were discussed. The results are summarized as follows:(1) We analyzed the difference among grafted parents tuber mustard (TTT: LI-LII-LIII), red cabbage (CCC:LI-LII-LIII), and chimeras (TTC, TCC, T:come from the tuber mustard, C:come from the red cabbage) in morphological characteristics. The stoma size of CCC is smaller than TTT, but the density is similar, with 10 and 9/field (each field of vision equal to 135μm×110μm) respectively. The stoma densities of two chimeras were 19 and 14/vision, showing significantly higher than that of two parents but no significant difference between them. Trichome density in chimera TTC is 38/cm2, which is significantly higher than the other three plants. No significant differences have been found between the parent TTT and the chimera TCC, the hair densities are 22/cm2 and 24/cm2 respectively. In addition, there are also significant differences in terms of leaf color and morphology.(2) In a Y-type olfaction instrument, we found that more B. tabaci adults were attracted to plants with more genetic information of cabbage, and when the difference of plants increased to two cell layers or more, the difference of attraction reached to significant level. In a cage choice experiment, more eggs were laid in tuber mustard. However, the number of eggs was not significantly different for the other three plants.The genetic differences of plants also have a great impact on oviposition and development of B. tabaci. Although eggs on tuber mustard, red cabbage and two chimeras can hatch normally, the chimera CCC harvested the largest egg laying, and there is no significant difference of egg laying among the other plants. However, there were significant differences in survival rate of the nymphs on different plants. The order of nymph survival rate is TTC> CCC= TCC> TTT. The shortest developmental time of nymphs (19.35 days) occured in tuber mustard, while it needs 3days more in red cabbage, and the time needed in chimera is between them..(3) Chimeras impact the development and fecundity of aphids. Tuber mustard and two chimeras, the genetic background of L I cell layer is same with tuber mustard, have no significant effects in development time of aphids. The green peach aphid is parthenogenesis. The different amount of nymph, in five days, showed us that the two parents have significantly difference. The number of nymph in tuber mustard is higher than in red cabbage. Each two of red cabbage and chimera TCC, TTC and tuber mustard have significant difference. To some extent, aphids do more harmful to tuber mustard.(4) Chimeras were used to test the impact on development of P. xylostella L. The development time of larvae on different plant has no significant difference, but survival rates vary greatly. Larvae on tuber mustard almost can develop to the fourth instars. Survival rates on red cabbage and chimera are only about 80%. During the pupation process, there are significant differences among chimeras and their parents. On chimera TCC, the rate of pupation is only about 50%, and on red cabbage and tuber mustard, the pupation rate are as high as 66%. To some extent, chimera is superior to the two parents. As to the weight of single pupa, there are no significant differences among them.(5) The variety of glucosinolate content in chimeras was also studied. The content in chimeras can be classified into two kinds. First, tuber mustard and red cabbage have significant differences, and chimera are between the two of them, and represented by 2-propenyl GS,3-butenyl GS and methyl-indole GS. The second is represented by 3-methylsulphinylpropyl GS and 4-methylsulfinylbutyl GS. This kind is superior to the two parents. |
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