氯化钠影响下蓝藻Anabaena 7120的固氮活性和去铵阻抑

NITROGENASE ACTIVITY AND NH_4^+-DEREPRESSION OF BLUE-GREEN ALGAE Anabaena 7120 UNDER INFLUENCE OF SODIUM CHLORIDE

正常培养液中NaCl浓度增高时,蓝藻固氮活性明显下降,去铵阻抑速率也减慢。NaCl浓度越高,阻抑程度越大。如果NaCl浓度过高,固氮酶活性即完全丧失,铵阻抑效应也不能消除。低光照度、光合抑制剂、O_2、N_2以及N_2+CO_2都加剧高浓度NaCl对蓝藻固氮酶活性和去铵阻抑的阻抑,而外源蔗糖、H_2和H_2+O_2则有一定程度的促进。

In this paper we found that the nitrogenase activity and the rate of H4+-derepression in Anabaena 7120 were declined with the increase of concentration of sodium chloride in culture solution.Over 1.5×10-1mol/L of sodium chloride there was a marked inaction in the nitrogenase activity and rate of NH4+-derepression.Under weak light condition or in presence of ph-otosynthetic inhibitors,such as DNP and salicyladoxime,MSX and chlor-amphenical,a great inhibition of nitrogenase activity arid rate of NH4+-der-epression of Anabaena influenced by increase of sodium chloride in culture solution were observed.But enhancing effect,occurred when external sucrose was added to culture solution.The characteristics of nitrogen fixation in Anabaena influenced by sodium chloride,depend upon the physiological conditions.It has been observed that.1.The addition of H2 together with O2 could accelerated nitrogenase activitty and NH4+-derepression of,Anabaena,influenced by higher concentration of sodium chloride,while depress by the oxygen alone.2.Under an atmosphere containing 5% CO2 or 5% CO2 and 20% N2 the nitrogenase activity and rate of NH4+-derepression in Anabaena influenced by sodium chloride in medium were decreased,but were promoted in normal cells of Anabaena.