准噶尔盆地无叶假木贼幼苗更新过程的生态学研究

Seedlings growth is crucial stage of desert plant life strategy in the arid and semi-arid area, which directly determines establishment and regeneration of plant population. Research about seedlings regeneration of desert plant is widely reported. But, some crucial ecological mechanism of seedlings regeneration is less involved, especially the responses of seedlings regeneration to snowmelt and rain pulse in global climate change. Anabasis aphylla is one of main constructive species of soil desert area in Junggar Basin, and has important role on maintaining water and soil safe of diluvial fan and plain. Furthermore, it is one resource plant species with great value. Through method of combining field investigation and observation with simulation experiment, ecological mechanism of seedlings regeneration is studied. First, effects of seeds size and burial depth on seedlings emergence are researched, and it will reveal ecological meaning on pushing diaspores to the soil surface. Second, the coupling mechanism between environment factors and snowmelt is studied, and effect on seedling regeneration due to shorter snowmelt period will be illuminated. Third, effect of rain pulse on seedlings growth and regeneration is considered, and which will discuss the meaning of rain pulse increase for seedlings regeneration. This project can get a better understanding about adaptation mechanisms of desert plant, has profound guiding significance on protection of resource plant and vegetation restoration in the desert area.

在干旱、半干旱区，幼苗是荒漠植物生活史中的关键阶段，直接决定着植物种群的建立和更新。有关荒漠植物幼苗更新的研究已有大量报道，但对一些关键的幼苗更新问题的生态学机制涉及较少，尤其是幼苗更新对全球气候变化要素中的融雪和降雨脉冲的响应。无叶假木贼是准噶尔盆地土质荒漠的建群种，对维护山前洪积扇的水土安全具有非常重要的作用，而且也是一种利用价值较高的资源植物。本项目拟采用野外定点观测与人工模拟相结合的方法，研究融雪植入和种子大小对出苗的影响，揭示植物繁殖体"融雪植入"土壤的生态学意义；研究融雪后环境因子动态及其对幼苗更新的影响机制，阐明全球气候变化下融雪环境持续期缩短对幼苗更新的影响；研究降雨脉动对荒漠植物幼苗生长和更新的潜在意义，探讨全球气候变化下降雨脉动增多对幼苗更新的促进作用。项目研究能够加深对荒漠植物适应机制的理解，对荒漠区资源植物保护和植被恢复具有指导意义。

项目针对旱生植物无叶假木贼的关键生态过程开展研究，以种群可持续发育为研究目标，主要从无叶假木贼种子生态适应性、无叶假木贼幼苗对降水的响应、无叶假木贼植株沙埋生态过程研究、无叶假木贼对干旱环境在解剖和生理方面的适应性研究、无叶假木贼种群格局及种内关联、无叶假木贼群落优势物种种群空间格局和竞争关系等方面开展了研究，重点研究了无叶假木贼幼苗更新障碍机制和探讨了全球气候变化背景下多因素耦合对幼苗建成的生态意义，提出了无叶假木贼群落恢复的策略，为荒漠资源植物的保护与利用提供依据。主要结论:1) 无叶假木贼种子能在低温条件下完成萌发是荒漠植物特殊的生物特性，在融雪期间进行萌发的现象是一种生态适应性。2）早春的融雪期持续的时间越长以及积雪量越大越有利于无叶假木贼种群的更新，而在全球气候变化背景下越早萌发的种子越有较高的存活概率。3）无叶假木贼大种子能在0.2～0.5厘米的覆沙中有较高的存活率，这可以减少融雪期后的迅速升温带来的干旱胁迫。4）在干旱区荒漠植物幼苗在定居过程中受降雪量、脉冲降雨量和频次、微地形等因素影响较大，而在全球气候变化背景下干旱区无叶假木贼幼苗的成功更新就与积雪量、脉冲降雨量和频次、微地形等因素的耦合才能完成，这就是在野外无叶假木贼幼苗有些年份几乎没有更新的原因。5）无叶假木贼幼苗在种群分布格局及其竞争关系方面以及对沙埋、降水、干旱等环境因子的响应是对干旱区极端环境的生态适应性。本研究发表论文5篇，其中sci收录3篇，出版专著1部。