短期低夜温处理对番茄光合作用的影响

为探讨短期低夜温胁迫对番茄光合作用影响的机理,以15℃夜温为对照,研究了6℃夜间低温处理7 d对番茄净光合速率、气孔开口面积和羧化效率日变化的影响。结果表明:6℃低夜温处理7 d后,番茄叶片净光合速率、气孔开口面积和叶片羧化效率全天皆低于对照;气孔导度(Gs)、胞间CO2浓度(Ci)、蒸腾速率(Tr)下降,气孔限制值(Ls)增大;气孔张开率上午提高,下午则显著降低;叶面积明显减小,叶片变厚,气孔器密度加大,而单叶气孔器数差异不显著,平均单叶气孔器变小。因此,低夜温处理后番茄光合作用降低的原因既有气孔限制因素,又有羧化限制因素;而且导致气孔限制的主要原因是气孔开口面积减小和午后气孔张开率降低。

Effects of low night temperature in short time on photosynthesis of tomato

Effects of low night temperature of 6 ℃ for 7 days(15 ℃ as control) on the net photosynthetic rate,stomata opening area and the diurnal changes of carboxylation efficiency were studied in tomato leaves,and the possible mechanisms were discussed.The results showed that the net photosynthetic rate,stomata opening area and carboxylation efficiency were lower than control during the whole day after tomato seedlings were treated for 7 days under low night temperature.The stomata conductance(Gs),intercellular CO2 concentration(Ci),transpiration rate(Tr) were decreased but stomata liminitation(Ls) was increased.The stomata opening ratio was increased in the morning after 7 days treatment,in contrast with the afternoon.Leaf area was significantly decreased.The thickness of leaf blade was thicker than control.The density of stomata organ in leaves was increased,but no significant difference was found about the quantity of stomata organ in each leaf,and the stomata organ in each leaf was decreased at average.These indicated that not only stomata limitation but also carboxylation efficiency limitation was the reason for the decreased photosynthetic rate during the treatment under the low night temperature.Moreover,the main reasons for stomata limitation can be that the stomata opening area and the stomata opening ratio were decreased.