高温强光对双荚决明的影响及其园林应用

The Effect of High Temperature and Intensity Light on the Physio-ecological Indexs of Cassia bicapsularis and its Application in the Landscape and Architecture

对双荚决明的色素、光合和荧光参数的高温强光下的变化进行了测定研究。结果表明:双荚决明的总叶绿素含量相对较高,不同叶位成熟叶片的叶绿素含量相差不大。双荚决明为强阳性植物,其光补偿点为12μmol.m-2.s-1,光饱和点为632μmol.m-2.s-1,最大的光合速率为5.840μmol.m-2.s-1,呼吸速率为0.819μmol.m-2.s-1;其CO2补偿点为70.4μmol.mol-1,CO2饱和点为883.2μmol.mol-1。双荚决明的净光合速率的日变化在4月份呈现出单峰曲线,最大值为4.6μmol.m-2.s-1,出现在12:00;8月份净光合速率的日变化呈现出双峰曲线,最大值分别出现在12:00时和14:00时,其最大值分别是4.2和4.6μmol.m-2.s-1。高温强光虽然对双荚决明的一定的影响但是整体变化幅度较小。双荚决明能适应8月23日平均气温为32℃,最高光强达2 130μmol.m-2.s-1的高温强光,也与净光合速率的日变化、光饱和点的测定数据相一致。根据测定的结果,建议双荚决明在园林中的主要应用形式为中篱、丛植、片植、高速公路或铁路边坡绿化和剪成球形观赏。

The contents of pigment, photosynthesis parameters and fluorescence parameters of Cassia bicapsularis were tested. The results showed that the Cassia bicapsularis was sun plant. The light compensation point was 20 μmol·m^-2·s^-1, light saturation point was 632 μmol·m^-2·s^-1 , the maximal photosynthetic rate was 5. 840 μmol·m^-2·s^-1, the respiration rate was 0. 819 μmol·m^-2·s^-1. Its CO2 compensation point was 70. 4μmol·mol-1, CO2 saturation point was 883.2 μmol·mol^-1 The diurnal change of net photosynthetic rate was a single-apex curve at April, the maximal value was 4. 6 μmol·m^-2·s^-1 at 12：00. The diurnal change of net photosynthetic rate was a double--apex curve at April;the mammal values were 4.2 μmol·m^-2·s^-1 and 4.6 μmol·m^-2·s^-1 at 12：00 and 14：00 respectively. The changes of fluorescence parameters showed that the high temperature and intensity light affect the growth of Cassia bicapsularis, but the ranges were small. The changes of fluorescence parameters showed that the could adapt the climate of August 23rd in 2009, the average temperature of 32℃ ,the maximal intensity light of 2 130 μmol·m^-2·s^-1. Those changes were corresponding with the diurnal change of net photosynthetic rate and light saturation point. On the basis of these results, we suggested that the application mode of Cassia hicapsularis in the landscape and architecture should be as middle-fense, clump planting, linear planting, greening planting on the road and railway slope and plastic reshaping.