岩溶木本植物对干旱的生理生态适应

受全球气候变暖和季风气候影响,西南岩溶区年降水量及其在季节间的分配发生明显变化,无雨期频率和持续时间增加,且基岩风化严重,基质储水能力差,致使岩溶木本植物面临的季节性和地质性干旱加剧。该文通过参考相关文献分析结构性状和生理调节探讨岩溶木本植物如何适应地质性和季节性干旱。结果表明岩溶木本植物应对干旱的策略与其他干旱、半干旱区的植物大体一致,主要有抗旱和避旱两种策略:抗旱性植物一般具有比叶面积小、叶肉多汁、储水组织发达、细胞液浓度高等适应干旱的特征,可通过增加木材密度、增强木质部导管的抗栓塞性和提高水分利用效率以适应干旱; 避旱植物则可通过小而密的气孔和叶脉、发达的表皮毛、栅栏组织和维管束鞘等结构特征减少水分丧失,并可通过落叶、深根吸收深层水源和脱落酸(ABA)介导提早关闭气孔以适应干旱。虽然关于岩溶植物形态结构和生理调节对干旱适应机制的研究取得了一定进展,但仍然存在一些亟待解决的问题,例如:深入研究岩溶地区基岩水分状况及其对植物的贡献; 加强岩溶木本植物根系结构和生物量分配、树木构型及根际微生物与木本植物干旱适应的协同关系研究; 同时探索如何将岩溶植物生态适应研究成果应用于生产实践中,科学指导石漠化治理与生态修复。

Physiological and ecological adaptation of karst woody plants to drought

Affected by global warming in southwest karst area and monsoon climate, the annual precipitation in southwest karst area and its distribution between seasons have changed obviously, and the frequency and duration of non-rain period are increasing. In addition, karst woody plants face more serious seasonal and geological droughts due to the strong weathering of bedrock and poor water storage capacity. This paper discusses how karst plants adapt to geological and seasonal drought by analyzing their structural characters and physiological regulation by referring to relevant literatures. The results indicate that like plants in arid and semi-arid areas, karst woody plants have two strategies to cope with drought: drought resistance and drought avoidance. Drought-resistant plants generally have some drought-resistant characteristics, such as small specific leaf area, succulent mesophyll, well-developed water storage tissue and high cell fluid concentration and so on, and can adapt to drought by increasing wood density, enhancing vessel anti-embolism and improving water use efficiency. Drought-avoidant plants can reduce water loss by small and dense stomata and leaf veins, developed superficial fur, palisade tissue and vascular sheath, and adapt to drought by defoliation, deep root absorption of deep water and early stomatal closure mediated by Abscisic acid(ABA). Although some progress has been made in the research on karst plants adapting to drought through morphological structure and physiological regulation, there are still some problems to be solved urgently, such as the study of bedrock water condition in karst area and its contribution to plants, the root structure and biomass allocation of karst woody plants, the relationship between tree configuration and drought adaptation and synergistic relationship between rhizosphere microorganisms and woody plants. At the same time explore how to apply the results of physiological and ecological adaptation of karst woody plants to drought in production practice, and scientifically guide the control and ecological restoration of rocky desertification.