银杏叶片三个不同发育阶段光合特性对CO_2浓度升高响应的比较研究

Comparison study on photosynthetic response to short-term elevated CO_2 in leaves of three developing stages of Ginkgo biloba L.

利用LI-6400便携式光合测定系统(L i-cor,USA),研究了银杏幼叶、全展嫩叶和成熟叶三个不同发育阶段Pn对短期CO2浓度升高的响应,并运用photosynthesis assistant software计算了它们的CCP、CE、Vcm ax、Jm ax。结果表明:CO2浓度升高过程中,银杏叶片三个发育阶段的Pn-CO2响应均为二次曲线,同一条件下,叶片光合作用的响应程度为成熟叶>全展嫩叶>幼叶,银杏成熟叶的CCP最低,CE、Jm ax和Am ax最高,作为幼叶与成熟叶过渡阶段的全展嫩叶其光合特性与幼叶更为接近。

LI-6400 photosynthesis measure system was used to measure the responses of Pn to shortterm elevated CO2 in expanding leaves, young fully expanded leaves and mature leaves of Ginkgo biloba L. CCP,CE,Vcmax and Jmax were calculated by photosynthesis assistant software according to Pn- CO2 curve. Results were summarized as follows： The responsive curves of Pn in leaves of three develop- ment stages of Ginkgo biloba L. to elevated CO2 concentration could be described with quadratic equations. On the same condition, the Pn of mature leaves was the highest and that of expanding leaves was the lowest. The CCP of mature leaves was the lowest and the CE,Jmax and Amax were the highest. Photosynthetic characteristics of young fully expanded leaves were more similar to expanding leaves.