盐胁迫下海马齿叶片结构变化

用石蜡切片法制片、光学显微镜观察了海马齿植物营养器官--叶片的盐适应结构变化,以明确盐生植物对盐渍生境适应的叶片结构变化特征,为盐生植物的耐盐机理研究提供依据.结果表明:(1)海马齿植物叶片表现出许多适应干旱和盐渍环境的特点,其基本特征为:叶片肉质化,为典型的等面叶;栅栏组织发达,且含有大量叶绿体;叶表皮气孔微下陷,叶表皮细胞外壁的角质层较薄,表皮细胞大小不等,外切向壁外凸,参差不齐,有些表皮细胞特化为泡状细胞,其数量与盐胁迫的浓度呈正相关.(2)叶的海绵组织中含有大量的薄壁细胞,幼叶海绵组织的薄壁细胞在0.5%～2.5% NaCl胁迫下均变大,且数量也增加;而老叶海绵组织的薄壁细胞只有在低浓度(0.5% NaCl)的盐胁迫下变大,而在高浓度下其薄壁细胞反而变小或成不规则形状.(3)盐晶广泛分布在海马齿的叶肉组织细胞内,且其数量随着盐胁迫浓度增加而增加.

Leaf Anatomical Structure of Sesuvium portulacastrum L.under Salt Stress

The leaf anatomical structure of Sesuvium portulacastrum was studied by using wax-slides and photo-microscopy.The observation of the leaf adapted structure will be meaningful for understanding the mechanism of halophytes in response to high salinity.The results indicate that anatomical acclimation to the salinity are described as the follows:the leaf of S.portulacastrum is isobilateral,and the stomatal apparatus are trapped in both sides of the epidermal cells which are varied in cell size,and less cuticularized cell wall.The vesicular bodies specified from epidermal cells are distributed in up-,and down-epidermal cell layers,which the numbers are increased to reflect the stressed salt concentrations.Double palisade mesophylls locate downstream of the epidermis,which are rich in chloroplasts.Many larger- vacuolated parenchyma cells distribute in the spongy tissue of leaves.These cells are larger in cell size and cell numbers in the young leaves of plants with 0.5%～2.5% NaCl stress,or old leaves of plants with 0.5% NaCl stress;while they become small or abnormal in shape in the old leaves of plants with 1.5%～2.5% NaCl stress.The salt crystals are found in the leaf tissue,those cells containing salt crystals were obviously increased as the treated salt concentration addition.