水分胁迫对紫背天葵光合生理特性的影响

在光辐射大于100μmol蛐（m2.s）的条件下,经多水处理紫背天葵（Begonia fimbristipula）叶片利用强光的能力较强,少水处理则其光合速率受到抑制.在弱光条件下,适水处理后紫背天葵叶片的净光合速率较高,光补偿点较低,叶绿素a的含量高,具有较高的光合能力.紫背天葵叶绿素的含量随土壤含水量下降而减少.在多水和少水处理条件下,紫背天葵叶片可溶性糖及MDA的含量有增加趋势;适水处理后紫背天葵具有良好的光合生理特性.紫背天葵在弱光条件下对水分胁迫有一定的适应性.

Effects of Water Stress on Photosynthesis Physiological Characteristics of Begonia fimbristipula

The capacity of utilization strong light for leaves of B.fimbristipula was stronger under watery treatments,but its photosynthesis capacity had been restrained under droughty treatments under ray radiation upon 100 μmol·（m2·s）-1.Under weak light conditions,there were higher net photosynthesis rates,lower light compensation points and more chlorophyll a contents in leaves of B.fimbristipula under moistness treatments,which indicated its stronger photosynthesis capacity.The chlorophyll contents of leaves of B.fimbristipula were cut down along with descending soil moisture contents.There were increasing trends for contents of soluble sugar and MDA in leaves of B.fimbristipula under watery or droughty treatments,but leaves of B.fimbristipula of moistness treatments displayed better photosynthesis physiological characteristics.B.fimbristipula had certain adaptability against water stress under weak light conditions.