氯化钠胁迫下蓝藻Anabaena 7120对氧的敏感性和氢的保护作用

OXYGEN-SENSITIVITY AND HYDROGEN-PROTECTION OF NITROGENASEACTIVITY IN BLUE-GREEN ALGAE Anabaena 7120UNDER STRESS OF SODIUM CHLORIDE

正常培养液中NaCl浓度增高时,蓝藻固氮活性下降,对氧的敏感度增大,氧浓度愈高,敏感度愈大。分子氢可以削弱或消除氧对固氮酶活性的抑制,其良好效应主要表现在固氮反应初期。 添加光合抑制剂、CO_2、N_2,以及在厌氧条件下,氢对NaCl胁迫下受氧伤害蓝藻固氮酶活性的保护效应低于对正常生长蓝藻的保护效应。

The nitrogenase activity of Anabaena 7120 was declined with the increase of concentration of sodium chloride in culture medium.The nitrogenase activity of Anabaena was more sensitive to oxygen under stress of sodium chloride than in normal condition.Molecular hydrogen significantly protected the nitrogenase activity from damage by oxygen in Anabaena under stress of sodium chloride as well as the normal condition.The inhibitory effect of oxygen on nitrogenase activity of Anabaena under stress of sodium chloride was occured at the begining of incubation.The protection by molecular hydrogen against O2-inactivation was effective also at the begining of incubation.When molecular hydrogen was added later,its protective action was weakened or disappeared.The highest protective action of molecular hydrogen was found when it was added together with oxygen.The pattern of the protective action of molecular hydrogen at light was similar to those obtained in dark.In the presence of photosynthetic inhibitor,CO2 or N2,or under anaerobic condition the protection of nitrogenase activity by molecular hydrogen against O2-inactivation was occured under stress of sodium chloride,but was not as much in normal condition.