高温、加富CO_2耦合对温室黄瓜光合作用及叶片衰老的影响

Effect of High Temperature and Elevated CO_2 Coupling on Photosynthesis and Leaf Senescence of Cucumber in Greenhouse

为了研究高温条件下,加富不同浓度CO_2对光合作用及叶片衰老的影响。以温室嫁接黄瓜为试材,研究了高温、加富不同浓度CO_2条件下黄瓜叶片的生长量、净光合速率及SPAD值的变化及功能叶和老叶中淀粉、可溶性糖和丙二醛(MDA)含量的变化,结果表明:与对照相比高温与不同浓度CO_2耦合,在处理7~19 d均提高了黄瓜叶片的净光合速率及SPAD值,但高温+高浓度CO_2处理,在试验开始13 d达到最大值后下降;高温+中浓度CO_2处理的黄瓜叶片的净光合速率及SPAD值,在叶片生育期10~19 d均显著高于对照、高温+低浓度CO_2以及高温处理。高温+高浓度CO_2处理的老叶与功能叶相比,淀粉含量显著上升,可溶性糖含量显著下降;而高温+中低浓度CO_2处理的老叶与功能叶的淀粉及可溶性糖含量并未出现明显变化。高温+高浓度CO_2处理的老叶丙二醛含量较功能叶显著增加,且老叶中丙二醛含量显著高于对照、高温+中低浓度CO_2及高温+低浓度CO_2处理。说明高温条件,加富高浓度CO_2能够快速促进光合作用增加,但会加速叶片老化,加富中浓度CO_2和低浓度CO_2能够促进光合作用持续增加,延缓叶片老化。

The changes of leaf area increase,photosynthetic rate,SPAD values of cucumber leaves and contents of starch,carbohydrate and MDA between functional leaves and old leaves were studied in greenhouse under high temperature and elevated CO2 coupling. The purpose of research was to investigate the effect of high temperature and elevated CO2 coupling on photosynthesis and leaf senescence of cucumber in greenhouse. Main results were as follows：Both the net photosynthetic rate and SPAD values increased markedly under high temperature and elevated CO2 coupling. But the values under high temperature with high concentration of CO2 reached at the peak level after treatment of 13 days; the values under high temperature with medium concentration of CO2 were significantly higher than control,high temperature with low concentration CO2 and high temperature treatments during 10-19 days. Comparing with the functional leaves,contents of starch went up and contents of carbohydrate declined remarkably in old leaves under high temperature with high concentration of CO2; while there was no significant change in contents of starch and carbohydrate under high temperature with medium and low concentration of CO2. The content of MDA in old leaves under high temperature with high concentration of CO2 grew significantly,and it was higher than those in other treatments except in high temperature treatment. The result above illustrated that under high temperature photosynthesis of cucumber would be increased quickly,but the speed of leaf senescence would also grew up with high concentration of CO2; while photosynthesis of cucumber would be increased continually,and the speed of leaf senescence would be decreased with medium concentration of CO2.