固氮蓝藻Nostoc commune和Anabaena azotica Ley耐盐性及机理研究

文章考察了两种固氮蓝藻Nostoc commune（地木耳）和Anabaena azotica Ley（固氮鱼腥藻）在不同浓度Na2CO3（0.2×10^-4～1.8×10^-4g/m l）的BG110培养基中的耐盐性。分别测定了两种固氮蓝藻在不同培养阶段的叶绿素a含量、胞外多糖含量、氨基酸含量和固氮酶活性的变化。研究结果表明两种固氮蓝藻都能在Na2CO3盐胁迫条件下生长,且随着Na2CO3盐胁迫性增加,两种蓝藻的叶绿素a含量、胞外多糖含量、氨基酸含量和固氮酶活性都呈现先增加后减少的趋势;而随着培养天数的增加,两种藻类叶绿素a的变化曲线与微生物的生长曲线很相似,胞外多糖和氨基酸的增长和叶绿素a的增长是同步的,其中,Anabaena azotica Ley的固氮酶活性在培养到21天时达到最大值,Nostoc commune的固氮酶活性在培养到28天时达到最大值;比较而言Anabaena azotica Ley的耐盐性好于Nostoc commune的耐盐性,固氮能力也高于Nostoc commune。

Study on the Salt tolerance and Mechanism of Nitrogen-Fixing Cyanobacteria Nostoc Commune and Anabaena Azotica Ley

Two species of nitrogenfixing cyanobacteria belonging to two genera Nostoc commune and Anabaena azotica Ley tolerate of different concentrations of Na2CO3 （ from 0.2 × 10^ -4 g/ml to 1.8 × 10^ -4 g/ml） in BG110 medium. The variation in the chlorophyll（Chl） a content, extracellular saccharide,amino acid and nitrogenase activity are measured respectively. It is found that both of nitrogenfixing cyanobacteria can thrive under Na2CO3 salt stress. When the concentration of Na2CO3 increase, the chlorophyll（Chl） a content ,extracellular saccharide ,amino acid and nitrogenase activity increase first and then decrease. With the increase of time of incubation, the change curve of chlorophyll（Chl） a content of Nostoc commune and Anabaena azotica Ley is similar to the growth curve of microorganism, extracellular saccharide and amino acid increase in a synchronism with chlorophyll （Chl） a, the maximum of nitrogenase activity appears at 21 days for Anabaena azotica Ley and appears at 28 days for Nostoc commune. Compare Anabaena azotica Ley with Nostoc commune, the former possesses better resistance to salt and higher nitrogen - fixing ability.