高温对20个鸡爪槭品种叶片形态和光合特性的影响

利用自然高温胁迫,研究了高温对20个鸡爪槭品种叶片形态、净光合速率、气孔导度、细胞间CO2浓度、蒸腾速率、水分利用效率和气孔限制值等参数的影响及各参数间的相关性,并以耐热性指标隶属度进行评价。结果表明,20个鸡爪槭品种的耐热性存在明显的差异,d1118和c1116是耐热性最强的2个品种,经过自然高温处理没有出现热害症状,y1106、y1107和x1119耐热性最差,其余品种介于2者之间;多数品种经热处理后净光合速率、气孔导度和蒸腾速率下降显著(P0.05)或极显著(P0.01),水分利用效率提高显著(P0.05),表现出明显的气孔抑制;品种d1118高温处理与对照相比净光合速率、气孔导度和蒸腾速率均显著增加,表现出极强的高温适应性;品种j1123高温条件下净光合速率下降,但仍保持较高的气孔导度和胞间CO2浓度,属于典型的非气孔抑制;高温引起的叶片热害症状与光合参数间不存在显著的相关性,但与蒸腾速率的相对变化值有显著(P0.05)的负相关。

Effects of heat stress on leaf morphology and photosynthetic characteristics of twenty Acer palmatum Thunb. cultivars

Twenty Acer palmatum Thunb. cultivars were treated under natural high temperature to study effects of heat stress on leaf morphology,net photosynthetic rate,stomata conductance,intercellular CO2 concentration,transpiration rate,water use efficiency,stomata limitation and correlations among these parameters. Results showed that（1） There existed significant differences in heat resistance among these Acer palmatum cultivars. Cultivars of d1118 and c1116 had the best heat resistance which showed no symptoms of heat injury after treatment while cultivars of y1106,y1107 and x1119 had the least heat tolerance and other cultivars were found fallen in between;（2） After heat stress,most cultivars showed obvious stomata suppression,which values of net photosynthetic rate,stomata conductance and transpiration rate were decreased significantly（P〈0. 05） or extremely significantly（P〈0. 01） and the water use efficiency was increased significantly（P〈0. 05）;（3） Cultivar of d1118 showed extremely high temperature adaptability because its net photosynthetic rate,stomata conductance and transpiration rate were significantly increased;（4） Cultivar of j1123 belonged to typical non-stomata limitation with decreased net photosynthetic rate but relatively high stomata conductance and intercellular CO2concentration;（5）Leaf heat injury caused by high temperature showed no significant correlation with photosynthetic parameters,but appeared an obvious negative correlation（P〈0. 05） with transpiration rate.