【摘要】 研究了不同温度、光照强度和O2水平下人参叶片光合速率对CO2水平的响应特性。结果表明:人参叶片光合作用CO2补偿点为36.6μmol.mol-1。CO2在36.6~500μmol.mol-1范围内,随CO2增加光合速率快速提高,羧化效率迅速下降;当CO2超过500μmol.mol-1时,随CO2的增加光合速率缓慢提高,羧化效率缓慢下降。低温和低光照强度均可成为人参叶片光合速率的限制因子。25 d叶龄的人参叶片光合速率对CO2水平的响应较敏感,当CO2从150μmol.mol-1增加到1 800μmol.mol-1时,光合速率提高216.7%(3.9μmol.m-2.s-1);63 d叶龄的人参叶片光合速率对CO2水平的响应不敏感。无O2时人参叶片的光合速率显著高于正常O2含量时的光合速率,但这种差异随CO2量的增加而逐渐缩小。更多还原

【Abstract】 Response characteristic of photosynthetic rate in leaves of Panax ginseng to CO₂ level under different temperatures,light intensity and oxygen levels was studied.The results showed that photosynthetic CO₂ compensation point was 36.6 μmol·mol^-1 in leaves of Panax ginseng.Under the range of 36.6500 μmol·mol^-1,the net photosynthetic rate increased quickly with the increase of CO₂ level,however,the carboxylation efficiency decreased significantly.The net photosynthetic rate increased slowly with the increase of CO₂ level beyond the 500 μmol·mol^-1,the carboxylation efficiency decreased slowly.Low temperature and low light intensity were limited factors for photosynthetic rate in leaves of Panax ginseng.It was sensitive that the response of photosynthetic rate to CO₂ level in the leaves of 25 days after full-unfolding of Panax ginseng.The net photosynthetic rate increased 216.7%(3.9 μmol·m^-2·s^-1)with CO₂ level increasing from 150 μmol·mol^-1 to 1 800 μmol·mol^-1.However,it was not sensitive that the photosynthetic rate responded to CO₂ level in the leaves of 63 days.Under low CO₂ level,the net photosynthetic rate under O₂-free conditions was significantly higher than that under normal O₂ conditions in leaves of Panax ginseng,but the difference was smaller and smaller with the increase of CO₂ level.更多还原