杂交棉及其亲本光合特性的研究

A STUDY ON COTTON HETEROSIS AND PHOTOSYNTHETIC CHARACTERS

本文研究了2种类型杂交棉及其亲本的光合特性，结果表明：棉花的干物质生产具有明显的杂种优势，这种优势主要来自叶面积的增大，而不是光合速率的提高。陆海与陆陆杂种的叶面积中亲优势率分别达到80％和30％。在自然强光条件下，海岛棉的光合速率低于陆地棉，但在9000lx的弱光条件下，则高于陆地植。陆海杂种的光合速率介于双亲之间，不表现杂种优势，陆陆杂种的光合速率亦接近双亲。海岛根与陆海杂种的光补偿点低于陆地棉，在3680～4500lx之间，陆地棉的光饱和点可达77000～86000lx，高于海岛棉。海岛棉的叶绿素含量比陆地棉高，但叶素a／b比则比陆地棉低，表明其属于光系统Ⅱ的捕获光能的叶绿素a／b蛋白复合物比较发达。陆海杂种的叶绿素含量与叶绿素a／b比均介于双亲之间。

Both total dry matter of cotton interspecific hybrid (G. barbadense × G.hirsutum) and cotton intraspecific hybrid shows significant superiority of heterosis. The su-periority does not comes from the increase of net photosynthetic rate (NPR) but from the en-largement of leaf area per plant. Under natural conditions, the NPR of G' barbadense is low-er than G. hirsutum, but under weak light, the NPR of G. barbadense is higher. The NPR of interspecific hybrid is between its parents and that of intraspecific hybrid close to its parents.The light compensation point of G. barbadense and interspecific hybrid is lower than that of G. hirsutum, while the light saturation point of G. hirsutum is higher than G' barbadense-G. barbadense has a higher content of chlorophvil than G. hirsutum, but its chlorophyll a/bvaule is lower than the latter. All this shows that G- barbadense has affluent light-trapping chlorophyll a/b protein cdmplex which belongs to ligh system Ⅱ.