盐胁迫下盐桦生理响应的变化分析

对组织培养获得的盐桦（Belula halophila）苗在盐胁迫下的生理指标和解剖结构进行了分析，结果显示，随着盐浓度的增加，植物叶片相对含水量逐渐降低；脯氨酸（Pro）含量逐渐增加；叶片丙二醛（MDA）含量和过氧化氢酶（CAT）活性大小存在相关性，在50～200mmol／L盐胁迫下，植物的CAT活性是递增的，200mmol／LNaCl处理时达到最高，同时叶片MDA含量在50～200mmol／L盐处理时变化不明显；CAT活性在300mmol／LNaCl处理时突然降低，此时叶片MDA含量大；植物叶片和根的离子含量测定表明，在盐胁迫下K^＋／Na^＋比值逐渐降低，叶片中K^＋含量始终高于Na^＋含量；石蜡切片和扫描电镜发现盐桦茎、叶中有晶体状物质存在，通过X-ray分析表明这种晶体含有C，O，Ca元素，相关的细胞成分化学实验进一步确定其结晶体的成分。

Physiological Responses of Betula halophila (Betulaceae) to Salt Stress

The physiological responses and the relevant anatomical structure of Betula halophila under salt stress were assayed. Results showed that the relative water and proline contents of the leaf were gradually declined, while the MDA content was correlated with the CAT activity in the leaf under salt stress. The CAT activity was ascended responding to the stability of MDA content at 50-200 mmol/L NaCl, but it was decreased at 300 mmol/L NaCl, which caused the elevation of the MDA. The K^＋/Na^＋ ratios in the leaf and root were declined under salt stress, while the K^＋ content was always higher than Na^＋ content in leaf. Crystals of Betula halophila containing the C, O and Ca element were discovered in the stem and leaf, but not in root, and will be further confirmed by chemical experiment related to cell components.