吉贝和攀枝花对温度升高的生理响应

以吉贝和攀枝花的半年生幼苗为材料，研究了2种植物随温度升高的生理变化。结果表明：吉贝和攀枝花的相对电导率都随温度升高而升高，其高温半致死温度分别为47.4 ℃和49.6 ℃。45 ℃处理后吉贝的叶绿素b和叶绿素(a + b)显著升高，37 ℃处理类胡萝卜素含量显著提高；随温度升高，攀枝花的叶绿素含量及其组分无显著变化，但类胡萝卜素含量也从37 ℃开始显著升高。45 ℃处理后，吉贝和攀枝花的初始荧光均显著升高，最大荧光及最大光化学效率均显著下降，但吉贝比攀枝花的变化幅度更大。2种植物的丙二醛含量随温度升高均呈上升趋势，其中吉贝的上升幅度大于攀枝花的上升幅度，但各温度处理间差异不显著。随着温度升高，吉贝的可溶性糖含量和脯氨酸含量及攀枝花的可溶性糖含量均无显著变化，攀枝花的脯氨酸含量显著升高。因此，攀枝花比吉贝的抗热性稍强，2种植物对温度升高的响应存在一定差异。

Physiological Response of Ceiba pentandra and Bombax ceiba to Temperature Increase

The physiological responses of Ceiba pentandra and Bombax ceiba to temperature increase were studied with half-year-old seedlings. The results showed that the relative electrical conductivity of C.pentandra and B.ceiba increased with the increase of temperature, and the semi-lethal high temperatres of them were 47.4 ℃ and 49.6 ℃, respectively. For C.pentandra, chlorophyll b and chlorophyll (a + b) increased significantly at 45 ℃, and carotenoid content increased significantly from 37 ℃. The chlorophyll content and composition of B.ceiba did not vary significantly with the increase of temperature, but the carotenoid content also increased significantly from 37 ℃. Fo increased and Fm and Fm/Fv decreased significantly for both the tree species at 45 ℃, but the variation of all the indexes mentioned above were greater in C.pentandra than those in B.ceiba. The content of malondialdehyde (MDA) in both of C.pentandra and B.ceiba not significantly increased with the increase of temperature, and MDA increased by a greater extent in C.pentandra. The content of soluble sugar and proline in C.pentandra and content of soluble sugar in B.ceiba did not vary with the increase of temperature, but the content of proline increased significantly in B.ceiba. In conclusion, the thermotolerance of B.ceiba is higher than that of C.pentandra, and they might adopt different mechanisms to cope with the increasing of temperature.