海岛棉叶片翘曲导致叶片光合能力的异质性

Heterogeneity of photosynthetic capacity in different parts of leaf induced by leaf cupping of pima cotton(Gossypium barbadense)

为了研究海岛棉叶片主脉两侧对称部位的光能截获与其形态及光合能力之间的关系,揭示叶片翘曲导致叶片光合能力异质性的生理机制,本研究以海岛棉"新海25号"叶片为材料,对叶片主脉两侧对称部分的光照日辐射、净光合速率、叶绿素含量及叶片面积进行测定比较。结果显示:海岛棉东西向叶片主脉两侧接受的总光能差异极大,南北向叶片差异较小;东西向叶片沿主脉接受光能较少的一侧,其叶片面积和净光合速率均显著低于截获光能较多的一侧,叶绿素a,叶绿素b和叶绿素(a+b)的含量显著高于截获光能较多的一侧,而南北向叶片主脉两侧的叶片面积、叶绿素含量及净光合速率均无显著差异。这表明海岛棉叶片翘曲引起不同方位叶片主脉两侧对称部分所截获的光能异质性,致使叶片面积和叶绿素含量的异质性,进而共同导致其光合能力的异质性。

The aim of this study is to study the relationship between the light interception and the morphology and photosynthetic capacity of the symmetric parts in leaf main vein of pima cotton, and to reveal the physiological mechanism of the photosynthetic heterogeneity induced by leaf cupping. The pima cotton （Xinhai No.25） were used as material, andthe daily photo irradiation net photosynthetic rate, chlorophyll content and leaf area of symmetrical parts in the leaf main veins of the were measured and analyzed in this study. The results showed that there was a obvious difference in the light interception between two sides of main vein in eastward and westward leaves, but less difference between the two sides in southward and northward leaves. At the same time, the leaf area and net photosynthetic rate on the side with less light energy along the main vein of eastward and westward leaves were significantly lower than the side with more light interception, whereas the content of chlorophyll a, chlorophyll band chlorophyll （a＋b） were significantly higher than the side with more light energy intercepted. However, there was no significant difference in leaf area, chlorophyll content and net photosynthetic rate on both sides of the main vein in southward and northward leaves. We concluded that the heterogeneity of light energy intercepted by the symmetric parts in leaf main vein at different orientation induced by leaf cupping of pima cotton results in the heterogeneity of the leaf area and chlorophyll content, thus leading to the heterogeneity of photosynthetic capacity.