State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China.
State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China; Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610299, China.
Sci Total Environ. 2024 Jun 1;927:172269. doi: 10.1016/j.scitotenv.2024.172269. Epub 2024 Apr 5.
Despite the extensive research conducted on plant-soil-water interactions, the understanding of the role of plant water sources in different plant successional stages remains limited. In this study, we employed a combination of water isotopes (δH and δO) and leaf δC to investigate water use patterns and leaf water use efficiency (WUE) during the growing season (May to September 2021) in Hailuogou glacier forefronts in China. Our findings revealed that surface soil water and soil nutrient gradually increased during primary succession. Dominant plant species exhibited a preference for upper soil water uptake during the peak leaf out period (June to August), while they relied more on lower soil water sources during the post-leaf out period (May) or senescence (September to October). Furthermore, plants in late successional stages showed higher rates of water uptake from uppermost soil layers. Notably, there was a significant positive correlation between the percentage of water uptake by plants and available soil water content in middle and late stages. Additionally, our results indicated a gradual decrease in WUE with progression through succession, with shallow soil moisture utilization negatively impacting overall WUE across all succession stages. Path analysis further highlighted that surface soil moisture (0- 20 cm) and middle layer nutrient availability (20- 50 cm) played crucial roles in determining WUE. Overall, this research emphasizes the critical influence of water source selection on plant succession dynamics while elucidating underlying mechanisms linking succession with plant water consumption.
尽管人们对植物-土壤-水相互作用进行了广泛的研究，但对于植物在不同演替阶段的水分来源的作用仍知之甚少。在这项研究中，我们结合使用水稳定同位素（δH 和 δO）和叶片 δC，研究了中国海螺沟冰川前缘在生长季（2021 年 5 月至 9 月）的水分利用模式和叶片水分利用效率（WUE）。我们的研究结果表明，在原生演替过程中，表层土壤水分和土壤养分逐渐增加。优势植物物种在展叶高峰期（6 月至 8 月）优先从上层土壤中吸收水分，而在展叶后期（5 月）或衰老期（9 月至 10 月）则更多地依赖下层土壤水源。此外，演替后期的植物从最上层土壤层吸收更多的水分。值得注意的是，植物对水分的吸收百分比与中晚期的有效土壤水分含量呈显著正相关。此外，我们的研究结果表明，随着演替的进行，WUE 逐渐降低，浅层土壤水分的利用对所有演替阶段的整体 WUE 产生负面影响。路径分析进一步强调了表层土壤水分（0-20cm）和中层养分供应（20-50cm）在决定 WUE 方面的关键作用。总的来说，这项研究强调了水源选择对植物演替动态的关键影响，同时阐明了演替与植物水分消耗之间的内在联系。
