盐度对盐生杜氏藻叶绿体超微结构的影响

Effect of Salinity on Ultrastructure of Chloroplast in Dunaliella salina

研究不同盐度对盐生杜氏藻（ Ｄｕｎａｌｉｅｌｌａｓａｌｉｎａ（ Ｄｕｎａｌ．） Ｔｅｏｄ ．） 叶绿体超微结构的影响．结果显示，在ＮａＣｌ 浓度为２ ．７ ｍｏｌ／Ｌ 的培养液中，其叶绿体为典型的杯状结构．在ＮａＣｌ 浓度从２ ．７ ｍｏｌ／Ｌ 增加到４ ．３ ｍｏｌ／Ｌ时，其杯状叶绿体逐渐离解为多个相互连结或分离的部分；叶绿体内的类囊体片层系统解体并出现大量的嗜锇质体小球；在分离的叶绿体间隙中形成多个线粒体．在培养液的ＮａＣｌ 浓度逐步从４ ．３ ｍｏｌ／Ｌ 降低到２ ．７ ｍｏｌ／Ｌ后，盐藻的叶绿体又逐步恢复为典型的杯状结构．由此可知，不同盐度下盐藻叶绿体的结构变化是一个可逆的过程，这种可逆变化是盐藻得以在高盐度，强光照，易蒸发的自然环境中生存的一种适应机制．

The ultrastructure of chloroplast in Dunaliella salina is studied under varied concentrations of NaCl. The results show that the algal cell has a typical cup shaped chloroplast in the medium containing 2.7 mol/L NaCl. As the concentration of NaCl increases from 2.7 to 4.3 mol/L, the chloroplast breaks into sevaral either independent or contacting parts gradually; the thylakoid system is disintegrated and replaced by numerous osmiophilic plastoglobuli; some mitochondria appear among the chloroplasts. As concentration of NaCl decreases from 4.3 to 2.7 mol/L, the chloroplasts of the alga can resume progressively to a typical cup shaped structure. Therefore, the change of chloroplast of Dunaliella salina is a reversible process, such reversibility makes it possible that the alga can live under the hypersaline, high light and evaporative environments.