Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China.
Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; State Key Laboratory of Desert and Oasis Ecology, Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China; Cele National Station of Observation and Research for Desert-Grassland Ecosystems, Cele 848300, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2024 May 15;925:171767. doi: 10.1016/j.scitotenv.2024.171767. Epub 2024 Mar 16.
Soil water conditions are known to influence soil nutrient availability, but the specific impact of different conditions on soil phosphorus (P) availability through the modulation of P-cycling functional microbial communities in hyper-arid desert ecosystems remains largely unexplored. To address this knowledge gap, we conducted a 3-year pot experiment using a typical desert plant species (Alhagi sparsifolia Shap.) subjected to two water supply levels (25 %-35 % and 65 %-75 % of maximum field capacity, MFC) and four P-supply levels (0, 1, 3, and 5 g P m y). Our investigation focused on the soil Hedley-P pool and the four major microbial groups involved in the critical phases of soil microbial P-cycling. The results revealed that the drought (25 %-35 % MFC) and no P-supply treatments reduced soil resin-P and NaHCO-Pi concentrations by 87.03 % and 93.22 %, respectively, compared to the well-watered (65 %-75 % MFC) and high P-supply (5 g P m y) treatments. However, the P-supply treatment resulted in a 12 %-22 % decrease in the soil NH-N concentration preferred by microbes compared to the no P-supply treatment. Moreover, the abundance of genes engaged in microbial P-cycling (e.g. gcd and phoD) increased under the drought and no P-supply treatments (p < 0.05), suggesting that increased NH-N accumulation under these conditions may stimulate P-solubilizing microbes, thereby promoting the microbial community's investment in resources to enhance the P-cycling potential. Furthermore, the communities of Steroidobacter cummioxidans, Mesorhizobium alhagi, Devosia geojensis, and Ensifer sojae, associated with the major P-cycling genes, were enriched in drought and no or low-P soils. Overall, the drought and no or low-P treatments stimulated microbial communities and gene abundances involved in P-cycling. However, this increase was insufficient to maintain soil P-bioavailability. These findings shed light on the responses and feedback of microbial-mediated P-cycling behaviors in desert ecosystems under three-year drought and soil P-deficiency.
土壤水分条件已知会影响土壤养分的有效性，但在极度干旱的荒漠生态系统中，不同水分条件通过调节磷循环功能微生物群落对土壤磷有效性的具体影响在很大程度上仍未得到探索。为了弥补这一知识空白，我们进行了为期 3 年的盆栽实验，使用典型的荒漠植物物种（沙生白刺），设置了两种供水水平（田间持水量的 25%-35%和 65%-75%，MFC）和四种磷供应水平（0、1、3 和 5 g P m y）。我们的研究重点是土壤 Hedley-P 库和参与土壤微生物磷循环关键阶段的四个主要微生物群。结果表明，与水分充足（65%-75% MFC）和高磷供应（5 g P m y）处理相比，干旱（25%-35% MFC）和无磷供应处理分别降低了 87.03%和 93.22%的土壤树脂磷和 NaHCO3-Pi 浓度。然而，与无磷供应处理相比，磷供应处理导致土壤中微生物偏好的 NH-N 浓度降低了 12%-22%。此外，干旱和无磷供应处理下参与微生物磷循环的基因（如 gcd 和 phoD）丰度增加（p<0.05），表明这些条件下 NH-N 积累增加可能会刺激解磷微生物，从而促进微生物群落投资资源以增强磷循环潜力。此外，与主要磷循环基因相关的 Steroidobacter cummioxidans、Mesorhizobium alhagi、Devosia geojensis 和 Ensifer sojae 等微生物群落在干旱和无磷或低磷土壤中得到了富集。总体而言，干旱和无磷或低磷处理刺激了参与磷循环的微生物群落和基因丰度的增加。然而，这种增加不足以维持土壤磷的生物有效性。这些发现揭示了在三年干旱和土壤磷缺乏条件下，荒漠生态系统中微生物介导的磷循环行为的响应和反馈。
