芽库对丘间低地植被发育过程的调控机制

As the base of vegetative propagation, bud bank plays a crucial role in plant population regeneration and colonization in response to disturbance and environmental stress. Although the ecological functions of bud bank in response to environmental stress and disturbance have been partly explored in various ecosystems, how bud bank size and composition and its regenerative contribution respond to wind activities and how the regenerative contribution of bud bank is linked to vegetation development in inter-dune lowlands have not been fully revealed. In view of this, this program will select inter-dune lowlands in Horqin Sand Land in Inner Mongolia as study objects, with the focus on the mainline of bud bank-ramet-vegetation. We will investigate the bud bank size and composition in inter-dune lowlands, monitor the sprouting and establishment of ramets, and dynamically track vegetation development processes. This program aims at exploring the effects of wind activities types (wind erosion or sand burial) and intensities on bud bank size, composition and regenerative contribution, comparing the roles of different bud bank types in plant adaptation to wind activities and vegetation development, and elucidating the processes and mechanisms of bud bank and its regenerative contribution in regulating the vegetation development in inter-dune lowlands. Based on the results, this program will enrich the theories of plant adaptive strategies and functional ecology of clonal plants, and provide guidance for implementing vegetation restoration of sand dune ecosystem in semi-arid region.

芽库作为营养繁殖的载体，在植物响应干扰与环境胁迫下的种群更新与拓殖中发挥至关重要的作用。尽管不同生态系统中芽库应对干扰与环境胁迫的生态功能已得到部分论证，但沙丘生态系统中,芽库大小与组成及其繁殖贡献如何响应风沙活动以及芽库繁殖贡献如何与丘间低地植被发育过程动态关联尚未得到充分揭示。鉴于此，本项目拟以内蒙古科尔沁沙地沙丘生态系统丘间低地为研究对象，以芽库-无性系分株-植被为主线，通过野外调查丘间低地芽库大小与组成，定位监测无性系分株形成与定植，动态跟踪植被发育过程，分析风沙活动类型与强度对芽库大小、组成与繁殖贡献的调控，进而揭示风沙活动下芽库驱动丘间低地植被发育的过程与机制，探讨不同类型芽库在应对风沙活动与植被发育过程中的生态功能差异，阐明芽库及其繁殖贡献对丘间低地植物发育的驱动过程与机制，丰富植物适应对策与克隆植物功能生态学理论，为半干旱区沙丘生态系统植被恢复提供理论依据。

芽库作为植物营养繁殖的基础，在植物响应干扰与环境胁迫下的种群更新与拓殖中发挥至关重要的作用。本项目以内蒙古科尔沁沙地沙丘生态系统丘间低地为研究对象，通过野外调查沙丘生态系统丘间低地芽库大小、组成与植物群落物种组成、多度、高度，室内分析土壤养分、水分及其交互作用对芽库的调控作用。阐明风沙活动类型对芽库大小、组成的调控，探究芽库大小与组成的季节变化及其面积效应，揭示流动与固定沙丘丘间低地芽库大小与组成的关键决定因素。研究表明：1）根茎芽对风蚀的适应性较强，分蘖芽对沙埋的适应性较强，根颈芽对水分亏缺的耐受范围较宽。同时，适度的风沙活动对根颈芽和根蘖芽的密度也有积极的影响；2）流动沙丘丘间低地地下芽库依赖于生长季节和丘间低地面积，生长季节和丘间低地面积之间存在显著的交互作用。首先，总芽库和根茎芽库密度在生长季高峰期达到最高峰，在生长季末最低，这可能受物候调节，而根颈芽则表现出相反的趋势，分蘖芽在生长季节没有明显的变化。另一方面，由于生态功能的差异，中等丘间低地的总芽库和分蘖芽库密度最高，根颈芽则呈相反的趋势，根茎芽不受丘间低地的影响；3）沙丘固定增加了芽库密度。土壤性质与植被密度分别是影响流动沙丘与固定沙丘丘间低地芽库密度的最重要因素。对于不同的芽型，流动沙丘丘间低地的根茎芽和根蘖芽更依赖于土壤水分含量，而固定沙丘间低地的根茎芽和根蘖芽与土壤总碳的相关性更大，分蘖芽与植被密度的相关性更大，根颈芽与所有影响因子无显著相关。本项目对丰富芽库生态功能研究、推动植物适应性策略理论发展，量化芽库对不同干扰与环境因子水平的响应具有积极的推动作用，为半干旱区沙丘生态系统植被恢复提供了理论依据。