葡聚六糖对黄瓜幼苗叶片光合速率及光化学效率的影响

寡糖片段在植物中作为一种早期信息分子可调节植物光合作用,但对于其调控机理尚不明确,有必要进一步探讨。用10μg.mL-1的葡聚六糖(P6)处理黄瓜叶片后能显著提高净光合速率(Pn),其效应可持续7d。葡聚六糖处理对胞间CO2浓度(Ci)无明显影响,但可显著提高气孔导度(Gs)和蒸腾速率(E),诱导24h后与对照相比分别提高107.1%和56.0%,说明其不是通过减少气孔限制来提高光合作用。同时,黄瓜叶片叶绿素含量、PSII反应中心的最大光化学效率(φPo)、光合机构电子传递的量子产额(φEo)、捕获的激子将电子传递到电子传递链中超过QA的其他电子受体的概率(ψO)、单位叶面积反应中心的数量(RC/CSo)等有所升高,而非光化学猝灭的最大量子产额(φDo)、初始荧光(Fo)和最大荧光(Fm)有所下降。可见,葡聚六糖可能通过增加叶绿素含量以及保持高效的光能吸收、传递和转换而使黄瓜叶片捕获更多光能,进而提高光合速率。

Effect of Glucohexaose on Photosynthetic Rate and Photochemistry Efficiency in Cucumber Seedling Leave

Oligosaccharide,act as an early regulatory molecules in plants,can regulate plant photosynthesis,but its regulation mechanism is not yet clear,and necessary to explore further.In the study,net photosynthetic rate of cucumber leaves could be enhanced after treated with 10 μg·mL-1 glucohexaose and the effect could last for 7 days.And intercellular CO2 concentration(Ci) had no significant effect,but stomatal conductance(Gs) and transpiration rate(E) were increased,After induced 24h,they increased by 107.1% and 56.0% compared with the control.so the improvement was not by reducing stomatal limitation.Meanwhile,the values of chlorophyll content,φPo,φEo,ψO and RC/CSo were improved significantly,but the values of φDo,Fo and Fm decrease,compared with the control.It appeared that increasing the chlorophyll content together with efficient light absorption,transmission and conversion contributes to the increasing photosynthetic rate.