单性木兰幼苗与成年植株叶片光合功能及结构比较

Comparison of Photosynthetic Function and Structure of Leaves between Kmeria septentrionalis Seedlings and Adult Plants

关键词:  单性木兰  光合特性  叶片结构  幼苗与成年植株  光响应

Key words:  Kmeria septentrionalis  photosynthetic characteristics  blade structure  seedlings and adult plants  light response

摘要:

为探究单性木兰（Kmeria septentrionalis）幼苗、成年植株叶片结构和光合特性的差异情况以及内在联系，揭示单性木兰叶片结构对光合速率的影响规律，本研究采用Li-6400便携式光合仪测定单性木兰幼苗和成年植株叶片的光合-光响应曲线，并通过电镜扫描比较其幼苗和成年植株叶面解剖特征的差异。结果表明：单性木兰成年植株的净光合速率显著高于幼苗；最大净光合速率（P_max）和光饱和点（LSP）存在显著性差异；成年植株对强光的利用能力高于幼苗，而幼苗较成年植株有更好的弱光利用能力；幼苗和成年植株的总叶绿素[Chl（a+b）]、类胡萝卜素（Car）、叶片厚度（LT）、气孔面积（SA）、气孔密度（SD）、栅栏组织厚度（PPT）和气孔横轴长度（SW）均存在显著性差异；Car、Chl（a+b）、SA和SD对光合生理特性的影响最为显著。因此，建议在单性木兰的引种栽培中，将幼苗进行遮阴处理，随着植株生长可适当减小遮阴度，待植株成年后可不做遮阴处理。

Abstract:

To explore the differences and internal connections in leaf structure and photosynthetic characteristics between Kmeria septentrionalis young and adult plants, so as to reveal the influence of leaf structure on photosynthetic rate and understand the response mechanism of young and adult plants to light, Li-6400 portable photosynthetic instrumental chemistry was used to analyze the light response curve of the leaves of the young and adult plants of K.septentrionalis.The research results indicate that the net photosynthetic rate of adult plants of K.septentrionalis is significantly higher than that of young plants;There is a significant difference in maximum net photosynthetic rate (P_max) and Light Saturation Point (LSP).Adult plants have a higher capacity to utilize strong light than seedlings, while young plants have a better capacity to utilize weak light than adult plants. There were significant differences in total chlorophyll Chl (a+b), Carotenoid (Car), Leaf Thickness (LT), Stomatal Area (SA), Stomatal Density (SD), Palisade Parenchyma Thickness (PPT) and Stomata Width (SW) seedlings and adults, Car, Chl(a+b), SA and SD in leaf structure have the most significant effects on photosynthetic characteristics.Therefore, it is recommended that in the introduction and cultivation of K.septentrionalis, young plants should undergo certain shading treatment.As the plant grows, the shading degree can be appropriately reduced, and shading treatment may not be required after the plant reaches adulthood.