硝酸钾缓解氯化钠胁迫蓝藻Anabaena 7120固氮的生理基础

PHYSIOLOGICAL BASIS OF MITIGATIVE EFFECT OF KNO3 ON NaCl STRESS IN NITROGEN FIXATION OF BLUE-GREEN ALGAE ANABAENA 7120

摘要:

营养液中添加适量ＫＮＯ₃可在一定程度上缓解ＮａＣｌ对鱼腥藻固氮活性的抑制作用。暗处理或加光合抑制剂时，ＫＮＯ₃对ＮａＣｌ胁迫的缓解作用便消失。供给外源蔗糖、提高ＣＯ₂浓度、同时供给ＣＯ₂和Ｎ₂时，ＫＮＯ₃对缓解ＮａＣｌ胁迫的作用则增高．同时供给Ｏ₂和Ｈ₂对ＫＮＯ₃的缓解作用增高影响较小，而在厌氧（Ａｒ或Ｎ₂中）或单加氧下，ＫＮＯ₃的缓解效应则明显减弱或消失．

Abstract:

The NaCl-induced inhibition of nitrogen-fixing activity of blue-green algae Anabaena 7120 was removed to a certain degree by the introduction of appropriate KNO3 into the culture medium.When the preincubation of algae cells was done in dark before experiment for 24 hours or in the presence of photosynthetic inhibitors,such as DNP or CCCP, the benefical effect of KNO₃ on the nitrogen-fixing activity of Anabaena treated with NaCl stress weakened or disappeared.In the addition of O₂ together with H₂ the mitigative effect of KNO₃on nitrogen-fixing activity of Anabaena was reinforced under NaCl stress.But a marked inaction in nitrogen-fixing activity of Anabaena occurred under NaCl stress when O₂was introduced into the test system alone.When algae cells treated with NaCl stress were incubated in the aerobic condition(in air)the benefical action of KNO₃ was higher than that in anaerobic condition(in Ar).The KNO₃supported nitrogen-fixing activity of Anabaena was more evident under NaCl stress in the prensence of the exogenous sucrose or CO₂.The migatative effect of KNO₃ on nitrogen-fixing activity of Anabaena was accelerated under NaCl stress in the addition of N₂ together with CO₂, while it was depressed by adding N₂ alone.