盐胁迫下藜的形态结构与生理响应

本文采用石蜡切片、扫描电镜和体视显微镜对藜进行了形态结构观察和多种生理指标检测，研究在盐胁迫下藜的结构和生理变化。结果表明：在花期，藜的株高和茎粗显著降低，叶未产生明显肉质化。高盐（300mmol·L^-1）胁迫下，叶维管束的导管数量及形成层层数增加，茎的维管束密度增加，根木质化程度增强，大导管密度显著降低。叶下表面的盐囊泡较上表面多，叶和茎细胞中均含有簇状结晶。随着盐浓度的升高，叶片中含水量降低，相对电导率升高，丙二醛（MDA）含量无显著变化，叶绿素含量在苗后期先升高后降低，在花期，其含量随盐浓度升高而降低。300mmol·L^-1盐胁迫下，苗后期的可溶性糖、脯氨酸7L-N-菜碱含量显著增J／w；至花期，脯氨酸及甜菜碱含量显著高于对照。以上结果初步显示，高浓度盐胁迫对花期的藜形态结构及部分生理指标均比苗期产生显著影响，但300mmol·L^-1盐胁迫下藜仍能完成其生活史。

Morphology and Physiological Responses of Chenopodium album L. under Salt Stress

The present study investigated the morphology and physiological changes in Chenopodium album under salt stress by observation of paraffin sections, scanning electron microscope and stereo microscope. The results showed that the plant height and stem diameter decreased significantly at flowering stage, while the leaf succulence was not evident. Under high salt （300 mmol.L1） stress, the number of vascular vessle and layer of cambium in leaf increased, and the vascular bundle density in stem also increased, the lignified degree of root enhanced, the density of large vessle in root reduced significantly. The salt bladders on the abaxial surface were more than those on adaxial surface, and some clusters of crystallization were observed in cells of leaf and stem. With the increase of salt concentration, water content decreased; the relative electric conductance increased, while MDA content showed no difference. The content of chlorophyll increased first and then decreased at the late seedling stage and decreased also at flowering stage with the increase of salt concentration. The contents of soluble sugar, proline and betaine increased significantly under 300 mmol.L^-1 NaCl at the lately seedling stage, and the proline and betaine at flowering stage were the same. The preliminary results suggested that under high salt concentration the morphology and physiological parameters showed more significant changes at flowering stage compared with the late seedling stage in C. album, however, 300 mmol.L^-1 NaCl stress did not affect its normal life cycle.