富钾入侵植物调控根系分泌物和根际解钾菌联合解钾机制研究

提高土壤营养元素有效性以促进自身生长是外来植物成功入侵的机制之一。土壤中98%以上钾素为非交换态，须经活化为有效态方可被植物利用，但不少入侵植物却能够提高土壤钾素有效性并大量富集钾素，而富钾入侵植物如何通过根际过程活化土壤钾素尚未得到深入研究。本研究以富钾入侵植物加拿大一枝黄花（Solidago canadensis）为例，对比研究不同钾素水平下入侵植物和伴生土著植物的生长和钾素积累特性，阐明根际土壤中钾素空间分布、形态转化和有效性变化规律，揭示入侵植物钾素活化特征；在此基础上，通过根系分泌物释放量、解钾活性和关键解钾化学组分的变化，以及受根系分泌物调控的根际解钾菌遗传多样性、解钾活性和关键调控组分的变化，阐明根系分泌物和根际解钾菌的联合解钾机制。通过本项目研究有助于阐明基于提高土壤钾素有效性并富集钾素的入侵植物-土壤反馈作用机制，为深入揭示外来植物成功入侵机理及制定有效防控方案提供依据。

Soil nutrients availability is frequently enhanced by exotic plant species invasion which promote its capacity for further invasion. More than 98% of total potassium is non-exchangble in soils and can be uptake only after being activated. However , many notorious invasive species can activate soil potassium and accumulate large amount of potassium in tissues. Up to now, how invasive species activates soil potassium via rhizosphere processes is unknown. This project aims to elucidate the processes of how invasive plant species responds to different soil potassium availability, regulates chemicals profile of root exudates and diversity of potassium-solublizing bacteria and enhances soil potassium availability. In this study, one of the potassium-rich and notorious invasive plant species, Solidago canadensis, is selected as an target species and compared to several accompanying native species. We study spatial distribution and transformation of potassium in soil and absorption by plants; the amount and chemicals profile of root exudates and their ability to activate soil potassium in response to soil potassium availability; diversity of potassium-solublizing bacteria and their ability to activate soil potassium and promote plant growth regulated by root exudates. This study will reveal the mechanisms of how potassium-rich invasive plant species enhances its ability to increase soil potassium availability and therefore may add more evidences how exotic species become successful in succeed in invaded regions.