太子参光合速率变化特征初探

Preliminary study on variation characteristics of photosynthetic rate in Radix Pseudostellariae

为探明太子参Radix pseudostellariae光合速率变化特征,采用Li-6400光合测定系统,在晴朗的天气测定了太子参倒二叶的光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gc)的日变化和不同生长期的变化。研究结果表明:太子参的光合作用日变化呈单峰型,不存在"光合午休"现象,光合速率和蒸腾速率都在很大程度上决定于气孔导度,气孔导度与光合速率和蒸腾速率均表现为极显著(P<0.01)的正相关关系。太子参光合速率和蒸腾速率都随着整个生长期的推进,先缓慢升高后在倒苗期间急剧降低。

In order to prove up the variation characteristics of photosynthetic rate in Radix Pseudostellariae. Under the proper condition of sunny day, Li-6400 portable photosynthesis system was used to study the diurnal and different growth periods variation in photosynthetic rate （Pn）, transpiration rate （Tr）, stomatal conductance （Gc） of the top second leaf in R. pseudostellariae. The results showed that the curves of diurnal variation in photosynthetic rate of R. pseudostellariae represented single peak type, and it did not exhibit the midday depression phenomena. The photosynthetic rate and transpiration rate of R. pseudostellariae, were depended on the stomata conductance in great extent, and both were extremely significantly positive correlated （P〈0. 01） with the stomata conductance. The photosynthetic rate and transpiration rate increased slowly, and then decreased rapidly during the withering period along with the growth of R. pseudostellariae