蚕丝蛋白溶液处理后生菜幼苗在高温胁迫下的生理生化变化

Physiological and Biochemical Changes of Lettuce Seedlings under Heat Stress after Silk Fibroin Solution Treatment

以瑞比特生菜为材料，4叶1心期幼苗于光照培养箱（20℃，9000Lx）中每天叶面喷施1次20～200mg／L质量浓度的蚕丝蛋白溶液，连续3d，以喷蒸馏水对照，然后置于高温胁迫条件下（昼温／夜温：40℃／30℃）生长3d，测定叶片各项生理生化指标。结果表明，经蚕丝蛋白溶液处理的幼苗，在高温胁迫下，超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性和可溶性蛋白含量均高于对照，而丙二醛（MDA）含量低于对照，其中以50mg／L大分子丝素蛋白和100mg／L小分子丝素蛋白质量浓度处理效果最好。蚕丝蛋白可能具有缓解高温胁迫对生菜幼苗造成的破坏作用。

20-200 mg/L silk fibroin solutions were sprayed on the leaves of lettuce seedlings at the fourth developed leaf stage and the control was sprayed with distilled water. They were growing in illumination box （20℃, 9 000 Ix）for 3 days. Then, the seedlings were stressed at 40℃ in daytime while 30℃ in night for 4 days, and the physiological indices of leaves were measured. The results showed that SOD, POD and CAT activities and soluble protein content in lettuce seedlings pretreated with silk fibroin solution were higher under heat stress than those in control, but the content of MDA was lower than that in control. And mitigative effect of 50 mg/L large molecular silk fibroin solution and 100 mg/L small molecular silk fibroin solution under the high temperature stress were better than others. The silk fibroin might have mitigative effect on the damage of the lettuce seedlings caused by high temperature stress.