油菜素内酯对苦瓜幼苗抗冷性的影响

Effect of brassinosteroid on improving chilling resistance of bitter gourd seedlings

【目的】筛选出油菜素内酯(BR)提高苦瓜抗冷性的最佳浓度,为解决苦瓜低温胁迫问题提供理论依据。【方法】设CK1和CK2为清水对照(CK1为常温处理,CK2为低温胁迫处理),通过对不同浓度(10-4、10-3、10-2、10-1、10mg/L)BR处理后的苦瓜幼苗进行(8.0±0.5)℃72h低温胁迫,并测定植株生长指标及功能叶片中的丙二醛(MDA)含量、可溶性蛋白含量、细胞质相对电导率及超氧化物岐化酶(SOD)、过氧化物酶(POD)活性等。【结果】与CK2相比,不同浓度BR处理可以促进苦瓜幼苗在低温下生长,其鲜物重和叶片叶绿素含量增加,冷害指数降低,POD、SOD活性增加,可溶性蛋白和Pro含量升高,并在一定程度上减缓叶片中MDA的积累,同时可以明显降低细胞质相对电导率。【结论】喷施不同浓度BR可有效提高苦瓜幼苗的抗冷性,其中以10-2mg/L浓度处理最佳。

[Abstract]The objective of the current study was to screen the optimum concentration of brassinosteroid （BR） to improve chilling resistance of bitter gourd seedlings in order to lessen the losses caused by low temperature stress. [Method]The plant growth indices, metabolites, viz., MDA and soluble sugar content, relative conductivity, and activities of peroxidase （POD） and superoxide dismutase （SOD） enzymes in the leaves were investigated in bitter gourd seedlings treated with different concentrations of BR （10-4,10-3,10-2,10-1 and 10 mg/L） under the conditions of low temperature （8.0±0.5℃） stress for 72 h, CK1 （normal temperature） and CK2 （low temperature stress） were set as controls. [Result]Different concentrations of BR treatment promoted the growth of bitter gourd seedlings and decreased the chilling effects （chilling index） by increasing the fresh weight, the contents of chlorophyll, soluble protein, proline, and the activities of POD and SOD enzymes, reducing the accumulation of MDA and decreasing the relative conductivity significantly, compared to CK2. [Conclusion]BR treatment with different concentrations could significantly enhance chilling resistance of bitter gourd seedlings, however, the best seedlings growth was observed in the treatment 10-2 mg/L concentration of BR.