钙对蓝藻固氮受氯化钠胁迫的缓解效应及其与生理条件的关系

THE MITIGATIVE EFFECT OF CALCIUM ON NITROGENFIXATION OF BLUE-GREEN ALGAE ANABAENA 7120UNDER SODIUM CHLORIDE STRESS AND ITSRELATION TO PHYSIOLOGICAL CONDITIONS

摘要:

氯化钠胁迫导致蓝藻固氮活性的下降，可因加人适当浓度的氯化钠而有一定程度的缓解．在光合作用受抑（暗处理或添加光合抑制剂）、厌氧（Ａｒ或Ｎ２中）和有分子氧的情况下，此种缓解作用减弱．光合作用、需氧代谢（通气）和羟化反应（同时供给氢和氧）正常进行以及碳架（添加外源蔗糖或提高ＣＯ２浓度）供应良好时，钙对氯化钠胁迫的缓解效应增大．改善合成固氮酶的物质基础供应（同时供应ＣＯ２和Ｎ２）对此也有一定的正效应．

Abstract:

The paper deals with the mitigative effect of calcium on NaCl stress upon nitrogenfixation of Anabaena 7120 under different physiological conditions.The followingobservations have been made:1.The nitrogen-fixing activity of Anabaena under NaCl stress was mitigated with theincrease of calcium chloride in culture solution.Over 5×10-4 mol/L CaCl2,there was amarked weakness in mitigative effect of calcium on nitrogen-fixing activity of Anabaenaunder NaCl stress.2. Under dark condition or in the presence of photosynthetic inhibitors, such as DNPand CCCP, the mitigative effect of calcium on NaCl stress upon nitrogen fixation byAnabaena was diminished,but enhancing effect occurred when exogenous sucrose wasadded to the culture solution.3.The mitigative effect of calcium on NaCl stress upon nitrogen fixation by Anabaenaunder anaerobic condition(in Ar or N2)was lesser than that under aerobic condition.4.The addition of H2 together with O2 could accelerated nitrogen-fixing activity ofAnabaena under NaCl stress, while further depress was observed by adding oxygen alone.5.The mitigative effect of calcium on NaCl stress upon nitrogen fixation by Anabaenawas slightly enhanced to a certain degree by the preincubation of 5% CO2 or of 5% CO2 with40% N2 respectively,but was abated by the addition of N2 alone.The mitigative effect of calcium on NaCl stress upon nitrogen fixation by Anabaenaand its regulatory mechanism were discussed.