佛甲草(Sedum lineare)在干旱条件下的气体交换

在干旱条件下,测定了广州市1、4、5和年期屋顶绿化植物佛甲草叶片的气体交换参数、相对含水量(RWC)和比叶重(LMA),探讨了佛甲草在屋顶绿化中的生理生态适应性.结果表明不同生长期佛甲草叶片的RWC和LMA相对较低,分别在81.79%～87.58%和0.059～0.072 kg·m^-2之间,RWC和LMA在不同生长期的差异不显著(P>0.05).不同生长期佛甲草的气体交换参数CO₂同化速率(A)、气孔导度(g_s)和蒸腾速率(E)均呈现相似的日变化格型,A、g_s和E的日均值差异不显著(P>0.05).A、g_s和E之间的日变化呈明显的正相关关系(P<0.01).根据植物的RWC和气体交换参数的特征,推断佛甲草属兼性CAM植物,不同生长期佛甲草的主要生理生态指标相似.

Gas exchange of Sedum lineare under drought condition

To investigate ecophysiological adaptability of roof greening plant Sedum lineare of one,four,five and six years old,relative water content(RWC),mass per unit leaf area(LMA),and diurnal variation of gas exchange parameters in leaf were measured under drought condition in Guangzhou,China.Both RWC and LMA were low,and their values were 81.79% 87.58% and 0.0590.072 kg·m^-2, respectively.S.lineare in different growth stages did not show significant change in leaf RWC and LMA(P<0.05).Gas exchange parameters including CO₂ assimilation rate(A),stomatal conductance(g_s),and transpiration(E)presented similar diurnal variation pattern in different growth stages of plant.There was also no significant variation in A,g_s and E(P<0.05)in different growth stages.A, g_s and E were significantly correlated with each other during a 24 h time-course(P<0.01).S.lineare is considered to be a facultative crassulacean acid metabolism(CAM) plant according to its characteristics of RWC and gas exchange parameters.There are similar major ecophysiological indices in 5.lineare in different growth stages.