Two grasses differ in their absorptive root physiological traits and rooting depth under drought in an alpine steppe

作者：Zhi Zheng, Yurui Zhang, Ziyue Li, Feifei Dong, Lijuan Chen · 发表于：Annals of Botany · 年份：2024 · DOI：10.1093/aob/mcae151 · 被引用次数：4 · 研究领域：Plant nutrient uptake and metabolism、Plant responses to water stress、Tree Root and Stability Studies

BACKGROUND AND AIMS: Absorptive root traits play important roles in acquisition of water and nutrients from soil by plants. Despite numerous reports on the changes in species dominance under long-term drought in grassland communities, few studies have specifically investigated absorptive root traits of these dominant species in grasslands, especially in alpine grasslands. METHODS: Here, two grass species (Leymus secalinus and Stipa purpurea) differing in their responses to drought were selected from an alpine steppe. A series of absorptive root traits were examined under drought in a 3-year glasshouse experiment. KEY RESULTS: We found that drought had no effects on root morphological and architectural traits, whereas root physiological traits and rooting depth differed in their responses to drought. Specifically, drought significantly reduced root respiration and enhanced organ carbon (C) exudation rate, carboxylate exudation rate, acid phosphatase activity and rooting depth of L. secalinus. In particular, L. secalinus released more citrate into the rhizosphere under drought than S. purpurea. In contrast, these root traits of S. purpurea remained relatively unchanged in response to the drought. These differential responses would render L. secalinus more competitive in acquisition of nutrients and water, thus contributing to its dominance in the community under drought. Moreover, root respiration was negatively correlated with organic C exudation rate, carboxylate exudation ra...