The Role of Calcium in Proline Accumulation under Osmotic Stress in Leaves of Chinese Fir Seedling

Free proline content in leaves of Chinese fir (Cunninghamia lanceolata) seedlings under different levels of osmotic stress induced by PEG increased quickly. Free proline content incresed with osmotic stress time(24, 48, 72, 96 h) and strength(-1.5, -2.5, -5.0, -10 MPa ). Free proline content in leaves under differet osmotic stress strength for 72 h incresed from 3.8 μg·g -1(Fw) to 5.5, 7.5, 16.0, 28.5 μg·g -1(FW), respectively. Calcium treatment made proline accumulation induced by osmotic stress obviously raisd. Under different osmotic stress time (24, 48, 72, 96 h), free proline contents with calcium treatment were 56.3, 63.6, 75.0, 10.2 per cent higher than that of the control, respectively. After treating for 24 h with calcium chelating agent EGTA(5 mmol·L-1) and calcium channel blocker CoCl2 (30 mmol·L-1), proline accumulation induced by culcium under osmotic stress decreased obviously. The results showed that the calcium in proline accumulation under osmotic stress has an importent role.