关键词: 喀斯特, 岩性, 植物适应, 水分利用策略, 基岩储水

Abstract: The karst region of Southwest China is characterized by extensive bedrock exposure and limited soil cover, forming a dual structure of soil and water. Such unique geological background makes epikarst water a critical water source for plants, while bedrock lithology is the key factor driving the development and water storage capacity of epikarst zone. Under the combined impacts of extreme climate events and frequent karstic drought, the sustainability of vegetation restoration faces severe challenges. It is crucial to clarify the influences of lithology-regulated water supply on plant adaptation strategies. We summarized research progress in the regulation of karst bedrock lithology on plant water source, transport, and utilization strategies. Lithology determines the water storage capacity of bedrock. Limestone features well-developed fractures and fissures that could store abundant water sources, while dolomite’ dense structure hinders bedrock fissure development, resulting in weaker water storage capacity. Rock moisture serves as a crucial water source for karst plants. Dominant species in limestone habitats typically possess deep root systems that capable of accessing karst aquifer water. Their hydraulic regulation tends to be “anisohydric strategy”, wherein plants maintain stomatal opening under drought stress to gain carbon benefits. Dolomite hillslopes are dominated by shallow-rooted herbaceous plants and shrubs relying primarily on recent precipitation or shallow soil water sources. Their water utilization exhibits a “short water age” pattern, where water remains for a short duration during storage and transport in the root zone. Karst plants cope with drought stress through water-conserving strategies, including switching water source depth, separating hydrological niches, and enhancing water use efficiency. Compared to plants on limestone-derived landscapes, shallow-rooted deciduous shrubs growing on dolomite-developed hillslopes face heavier drought mortality risks. Future research should quantitatively characterize the coupling processes and feedback mechanisms among lithology, water availability, and plant adaptation. This could provide scientific basis for assessing vegetation dynamics and achieving high-quality vegetation restoration in ecologically fragile karst ecosystem.

Key words: karst, lithology, plant adaption, water-use strategy, bedrock water storage