绿僵菌粗毒素对竹织叶野螟幼虫血细胞的影响OA北大核心CSTPCD

The effects of Metarhizium anisopliae crude toxins on Algedonia coclesalis larvae hemocytes were investigated by determining the insecticidal potency of different concentrations(200,500,1 000,2 000,and 5 000 mg·L-1)of the crude toxins against A.coclesalis larvae.Changes in hemocyte counts and morphologies were then assessed in A.coclesalis larvae,which were fed M.anisopliae crude toxins at 5 000 mg·L-1 concentration.Cumulative collective mortality after feeding 4 to 5 instar larvae for 9 days with 5 000 mg·L-1 M.anisopliae crude toxins using the leaf dipping method was 97.37%,and the LT50 was 3.91 days.After feeding on crude toxins,the total hemocyte concentration in A.coclesalis larvae first increased,then decreased with extended treatment time,displaying a maximum value of 5.92×106 pcs·mL-1 when the duration of treatment reached 2.0 d,significantly higher than that of the control(P<0.01).Among the hemocytes,the concentrations of granulocytes and plasmatocytes showed increasing,followed by decreasing trends with prolonged treatment time.Both reached their respective maximum values(26.99×105 pcs·mL-1 and 22.85×105 pcs·mL-1)when the duration of treatment reached 2.0 d.These values were significantly higher than that of the control(P<0.01);prohaemocytes and spherulocytes reached their maximum densities when duration of treatment reached 1.5 d and 2.0 d,respectively significantly higher than that of the control(P<0.01)then rapidly decreased.Oenocytoid concentration showed a decreasing trend with prolonged treatment time.Our analyses of the proportions of various types of hemocytes in the larvae of A.coclesalis after feeding on M.anisopliae crude toxins revealed a rather high proportion of granulocytes,ranging from 42.1%to 47.9%.The proportion of plasmatocytes increased significantly with prolonged treatment time to 39.9%at 3.5 d(P<0.05).Microscopic observation revealed ruptured,vacuo lated hemocytes that exuded their contents when A.coclesalis larvae fed on the crude toxins for 2.0 d.Collectively,M.anisopliae crude toxins exhibited strong toxicity against A.coclesalis larvae,exerting a huge impact on hemocyte concentration and hemocyte morphology within 2-3 days.