高温胁迫下不同耐热性萝卜幼苗生理响应分析

利用耐热性差异显著的萝卜自交系为材料,研究了高温(38℃)胁迫下萝卜幼苗丙二醛(MDA)、游离脯氨酸、可溶性蛋白和可溶性糖含量变化与耐热性的关系。结果表明:高温处理前耐热材料中可溶性蛋白含量高于不耐热材料;可溶性糖、游离脯氨酸和MDA含量无显著差异。处理24、48、72h,耐热材料中可溶性蛋白、可溶性糖和游离脯氨酸含量均显著高于不耐热材料,MDA含量显著低于不耐热材料。处理24h,4个指标的含量都比处理前显著增加,可溶性蛋白含量在处理48、72h时逐渐降低,但耐热材料下降得较慢。与处理24h相比,处理48、72h时可溶性糖、游离脯氨酸和MDA含量在耐热材料中没有显著变化,而在不耐热材料中处理48h显著高于处理24h时的含量。表明这4个指标的含量变化能准确反映萝卜幼苗耐热性差异,可考虑用于萝卜幼苗的耐热性鉴定评价。

Physiological Response to High Temperature Stress in Radish Seedlings with Different Heat Tolerance

Under high temperature stress（38 ℃）, the variation of MDA, soluble protein, soluble sugar, free proline contents in radish（Raphanus sativus L.）seedling with different heat resistance were analyzed. The soluble protein content was higher in heat resistant inbred lines than that in heat-sensitive ones, while the content of soluble sugar, free proline and MDA exhibited no significant difference among inbred lines. Under the treatments of 38 ℃ for 24 h, 48 h and 72 h, the contents of soluble protein, soluble sugar and free proline in heat resistant inbred lines were significantly higher than those in heat-sensitive ones, while the MDA content was significantly lower in heat resistant materials. Under the treatment of 38 ℃ for 24 h, the contents of all the 4 indexes were significantly increased. The soluble protein content declined continuously for 48 h and 72 h, but it declined much slowly in heat resistant inbred lines. As compared with the treatment of 38 ℃ for 24 h, the contents of soluble sugar, free proline and MDA were significantly higher for 48 h in heat-sensitive materials, while in heat resistant materials, there were no significant increases for 48 h and 72 h. It was suggested that the variation of these 4 indexes was related with the heat resistance and could be used for evaluation of heat resistance in radish seedlings.