盐胁迫下海马齿叶肉细胞超微结构观察

Ultrastructural Observation of Mesophyll Cells of Salt-stressed Sesuvium portulacastrum L.

通过透射电镜,在超显微结构水平上对淡水和海水栽培的海马齿(Sesuvium portulacastrumL.)植物叶肉细胞结构进行了比较。结果显示:海水栽培的海马齿叶肉细胞质膜明显向内折叠,出现大量大小、形状各异的质膜突起,以及质膜片层;而淡水栽培的海马齿叶肉细胞质膜向内折叠不明显,质膜突起少见。相对于淡水栽培,海水栽培的海马齿植物叶肉细胞叶绿体变小、数量增多;形状变短,由肾形、梭形或弓形变成椭圆形或一端膨大的不规则形状;叶绿体基粒片层结构清晰完整,垛叠程度增加,叶绿体没有受到明显伤害;叶绿体中淀粉粒数量增多,体积变大,淀粉粒表面出现皱褶,形状由长椭圆型变成短椭圆形或不规则形状,电子密度变低;叶绿体上脂质体增多且体积变大。线粒体数量增加,但体积变小;形状由圆球状或棒状变成椭圆体状;线粒体内膜向内折叠所形成的嵴清晰,但海水栽培的海马齿叶肉细胞线粒体外膜模糊,受到轻微伤害。

The ultrastructural comparison between salt-stressed and non-salt-stressed mesophyll cells of Sesuvium portulacastrum was performed by using transmission electron microscope（TEM）. The results showed that cell plasma membranes of salt-stressed mesophyll cells invaginate obviously and form more vesicles varying in size and shape than those of the controls. In comparison with the non-salt-stressed cells, the salt-stressed cells had smaller chloroplasts but larger in quantity and short in shape（from kidney-shaped, spindle-shaped or arch shaped to oval or irregular shape with one end enlarged）. The chloroplasts in leaves of the salt-stressed S. portulacastrum had clearer and more integral grana lamella with more grana stacks of thylakoids than those in the plants under non-salt-stressed conditions and were hence not obviously injured. More and larger starch grains with uneven surface and lower electronic density were developed inside the chloroplasts of the salt-stressed plants, and the starch grains changed their shapes from oblong to narrow oval or to irregular shape. Inside the chloroplasts of the salt-stressed plants, the lipid bodies were increased in both quantity and size. The mitochondria inside the mesophyll cells of the salt-stressed plants were increased in quantity, but smaller in size with their shapes changing from spherical or clavate to ellipsoid. Internal membranes of mitochondria were inwardly folded and form clear cristae, but their out membranes were blurred with slight injury.