短时间高温对蓝藻Anabaena 7120固氮酶活性的影响

蓝藻Anabaena 7120经短时间高温处理后,其固氮酶活性、吸氢和放氧活性均下降,固氮酶活性对氧和pH变化的敏感性增大,受分子氢支持和一氧化碳抑制的程度增高。光合抑制剂或弱光加剧短时间高温处理对蓝藻固氮酶活性的抑制程度。

EFFECT OF HIGH TEMPERATURE ON NITROGENASE ACTIVITY OF BLUE-GREEN ALGAL Anabaena 7120

The results showed that the nitrogenase activity of Anabaena 7120 was decreased when treated at high temperature (45℃) in short time,The rate of nitrogenase activity was declined with the increase of temperature. Over 80℃) there was a marked inaction in the rate of acetylene reduction.The characteristics of nitrogen fixation in Anabaena 7120 influenced by high temperature in short time,depend upon the physiological conditions. It has been observed that:1. nitrogenase activity of Anabaena 7120 influenced by high temperature was more sensitive to oxygen and higher pH value of culture solution;2. the nitrogenase activity of Anabaena 7120 influenced by high temperature was suppressed by CO; 3.the nitrogenase activity of Anabaena 7120 influenced by high temperature _was more obvious than that of normal ones when H2 is present;4.the suppression of nitrogenase activity by CO2 and N2 in Anabaena 7120 influenced by high temperature was near to those obtained in the normal cells of algal.Under weak light condition or in presence of photosynthetic inhibitors, such as DNP and CCCP, a great inhibition of nitrogenase activity of Anabaena 7120 by high temperature was observed.The physiological significance of high temperature on nitrogen fixation blue-green algal Anabaena 7120 in short time was discussed.