中文摘要：

【目的】对发状念珠蓝细菌细胞进行重金属离子Cu2＋（CuSO4）、Cr2＋（CrCl2）和Pb2＋（PbCl2）胁迫,探讨发状念珠蓝细菌细胞对重金属离子胁迫的响应。【方法】25℃,80μmol/（m.s）光照下,BG11培养液培养发状念珠蓝细菌,利用不同浓度（0、0.1、1.0、10、100 mg/L）Cu2＋、Cr2＋和Pb2＋胁迫发状念珠蓝细菌细胞,测定其质膜透性、超氧化物歧化酶活性、丙二醛含量、脯氨酸含量、可溶性蛋白含量以及海藻糖含量,分析发状念珠蓝细菌细胞对重金属离子胁迫的响应。【结果】在Cu2＋、Cr2＋和Pb2＋胁迫下,发状念珠蓝细菌细胞的外渗率和丙二醛（malondialdehyde）含量随着重金属离子浓度的升高而升高,相对渗透率和膜脂过氧化水平的变化趋势一致。超氧化物歧化酶（superoxide dismutase）活性随重金属离子浓度的升高先升后降,脯氨酸含量随着重金属离子处理浓度的升高,呈先降后升的趋势,可溶性糖含量随浓度的增大而减少。【结论】低浓度的重金属离子可以诱导发状念珠蓝细菌细胞产生结构和生理的应激响应,高浓度会导致发状念珠蓝细菌细胞膜结构和功能的严重损害。

英文摘要：

[Objective] This study aimed to investigate the effects of Cu2＋,Cr2＋ and Pb2＋ stress on Nostoc flagelliforme cell.[Methods] The response of Nostoc flagelliforme cell was analyzed under the stress.The modified BG11 culture medium containing different heavy metal ions of 0,0.1,1.0,10,100 mg/L was used to cultivate Nostoc flagelliforme cell at 25℃ and light intensity of 80 μmol/（m·s）.Electrolyte leakage,the activities of superoxide dismutase,the content of malondialdehyde,proline,soluble protein and trehalose were analyzed.[Results] Under 1-100 mg/L Cu2＋,Cr2＋ and Pb2＋ stress,electrolyte leakage and malondialdehyde contents in Nostoc flagelliforme cell were higher than those in the control group during heavy metal ions stress.Meanwhile,superoxide dismutase activity increased slightly under 10 mg/L,but was lower afterwards.The contents of proline,soluble protein and trehalose increased under 10mg/L heavy metal ions stress,while declined under extreme heavy metal ions stress（100 mg/L）.[Conclusion] Nostoc flagelliforme cell has resistance to low heavy metal ions stress,but is damaged badly under extreme heavy metal ions stress.