石生南亚毛灰藓在不同温度和干旱条件下的生理生化特性

通过模拟高温和干旱处理,对喀斯特石漠化生境中南亚毛灰藓(Homomallium simlaense(Mitt.)Broth.Mitt)在胁迫条件下生理特征的变化进行了研究。结果表明,南亚毛灰藓在高温和干旱条件下,各项生理指标均与相对含水量呈显著正相关;丙二醛、渗透调节物质和叶绿素含量均随处理时间的增加和含水量的降低而减少,但植株仍保持较高的可溶性糖含量以维持渗透压的平衡。在极端干旱和高温的条件下,南亚毛灰藓可通过降低生理活性,保持一定的可溶性糖含量度过胁迫期,同时丙二醛含量保持最低状态。高温和干旱处理结束后,进行复水处理,植株的渗透调节物质和丙二醛含量显著升高,光合作用迅速恢复。研究结果表明,南亚毛灰藓适应干旱和高温的极端条件可能与丙二醛含量有关,但复水结束后丙二醛含量升高,胁迫反而增强,说明南亚毛灰藓对高温和干旱具有一定耐受性,原因可能与其长期生存于喀斯特的石生环境有关。

Physiological and biochemical characteristics of epilithic moss Homomallium simlaense (Mitt.) Broth. Mitt under high temperature and drought stress

Desert karst habitats are an important factor restricting the growth of karst plants. High temperature and drought stress caused by extreme climatic events bring new challenges to the adaptation of karst moss plants to environmental changes. In this study, we simulated high temperature and drought stress experiments to investigate the physiological changes and adaptability of epilithic moss (Homomallium simlaense (Mitt.) Broth. Mitt) under stress conditions in the karst environment. Results showed that the physiological and biochemical indices of H. simlaense exhibited significant positive correlations with the relative water content in plants under high temperature and drought treatment. The MDA, osmotic adjustment substances, and chlorophyll content decreased with decreasing moss water content and with increasing temperature and drought treatment duration. However, H. simlaense maintained a higher soluble sugar concentration to maintain the balance of osmotic pressure. In addition, H. simlaense also survived extreme drought and high temperature stress by decreasing physiological activity and maintaining soluble sugar content within a certain range. At the same time, the MDA content was at the lowest level. Restoring water after drought, the osmotic adjustment substances and MDA contents were higher than that of plants under continual high temperature and drought stress, and the photosynthetic capacity also recovered rapidly. Results suggested that the adaptation of H. simlaense to drought and high temperature may be closely related to increasing MDA content. Thus, H. simlaense showed resistance to high temperature and drought stress partly due to its long-term residence in harsh karst environments.