Abstract Studies on the regulation function of calcium on photosynthesis of Dimocarpus longana under simulated acid rain stress showed that the photoreduction activity of chloroplasts was activated when the concentration of calcium ion in reaction medium ranged from 0 to 5 mmol稬-1,and peaked at the 3.5 mmol稬-1, which was 41.90% higher than that of control. Conversely,the activity of chloroplasts reduced 26.06% in the reaction medium with a concentration of 2 mmol稬-1 EGTA,as compared with the control. Both Mn2+ and Mg2+ could inhibit photoreduction activity. The photophosphorylation activity increased when the concentration of calcium ion in reaction medium ranged from 0 to 6 mmol稬-1,and peaked at the 4.5 mmol稬-1,while superoxidase dismutase (SOD) activity rose from 0 to 6 mmol稬-1 and peaked at 6 mmol稬-1. Calcium ion with the concentration of both 10 mmol稬-1 and 15 mmol稬-1 could increase the content of chlorophyll(Chl),stabilize the membrane structure of leaf discs,and reduce the membrane permeability under simulated acid rain with pHvalue of 3.0. The effect in15 mmol稬-1 were better than in10 mmol稬-1. However,the injury of acid rain to leaves was strengthened when the concentration of calcium was higher than20 mmol稬-1. Net photosynthesis rate (Pn) rose when leaves sprayed with 15 mmol稬-1 Ca(NO3)2 before treatment of acid rain stress of pH2.5. All of the results represented the excellent protection function of calcium on D.longana leaves under simulated acid rain.
QIU Dongliang,LIU Xinghui,GUO Suzhi. Regulation function of calcium on photosynthesis of Dimocarpus longana Lour. cv. wulongling under simulated acid rain stress[J]. Chinese Journal of Applied Ecology, 2002, (9): 1072-1076.