镁对黄瓜生长和光合特性的影响

温室条件下研究了镁胁迫对黄瓜开花结果期生长和光合特性的影响.结果表明,镁胁迫抑制了黄瓜的生长,降低了黄瓜产量和黄瓜叶片叶绿素a、叶绿素b、类胡萝卜素的含量;黄瓜叶片净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)的日变化在缺镁胁迫下呈单峰曲线变化,而在多镁胁迫下Pn和Tr呈近似双峰曲线,Gs和Ci呈近似倒抛物线;多镁和适镁处理叶片的光饱和点、CO2饱和点以及表观量子效率和羧化效率均大于缺镁处理.缺镁胁迫下黄瓜光合作用主要是受非气孔限制,而多镁胁迫下气孔因素和非气孔因素二者兼具.

Effects of Magnesium Stress on Growth and Photosynthetic Character of Cucumber

The effects of magnesium stress on the growth and photosynthetic character of cucumber were studied in green house.The results showed that plant growth was inhibited and yield, the contents of chlorophyll A, chlorophyll B and carotenoids were decreased under magnesium stress.Net photosynthesis rate(P_n),stomata conductance (G_s)and transpiration rate (T_r) changed in one-peak curve under Mg-deficiency, and those decreased with the decrease of magnesium supply, P_n and T_r changed in double peak curve and T_r in Inverted parabolic curve under Mg-excessive in daytime.Light saturation point,CO₂ saturation point increased in Mg-excessive and decreased in Mg-deficiency leaves P_n maximum at saturated light decreased in Mg-deficiency leaves.The main limiting factor of photo-synthesis of cucumber seedling is non-stomata factors under magnesium deficiency;They were both stomata and non-stomata factors under magnesium excessive.