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土壤生态学快报（英文）
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2026年3期
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Root carboxylate release of native plants in the Hengduan Mountains: Insights from X-ray fluorescence results on leaf manganese concentrations in herbarium specimens
Root carboxylate release of native plants in the Hengduan Mountains: Insights from X-ray fluorescence results on leaf manganese concentrations in herbarium specimens
摘要
Root carboxylate release is a key strategy to mobilize poorly-available soil phosphorus (P). China?s Hengduan Mountains (HDM) are a global biodiversity hotspot covering various landscapes low in P availability, with the significance of root-released carboxylates in native species remaining unexplored due to challenges to assess exudates in natural habitats. Recently, leaf manganese (Mn) concentrations [Mn] as a proxy for root carboxylate exudation has been gaining acceptance. In the present study, using a handheld X-ray fluorescence (XRF) spectroscopy system, we analyzed leaf [Mn] rapidly and nondestructively, of herbarium material of 219 species of Cyperaceae, Asteraceae, Fabaceae, Brassicaceae, Polygonaceae, and Poaceae collected from HDM. We found more than 75% and 34% of analyzed species exhibited a mature leaf [Mn]? 100 and 300 mg Mn kg
?1 respectively, which is similar to that of positive reference species of Cyperaceae, of which most species release large amounts of carboxylates. We observed major variation in leaf [Mn] in Fabaceae and grew six of these in low-P nutrient solution. Fabaceae with high leaf [Mn] tended to show rapid root carboxylate-exudation rates.
Astragalus tongolensis showed low leaf [Mn] but also exhibited a rapid exudation rate of carboxylates, likely due to exudation of cations which may increase soil pH and reduce soil Mn availability. We show a rapid and nondestructive pipeline to analyze leaf [Mn] of herbarium material for an exploratory survey, and our validation within Fabaceae confirms the correlation between leaf [Mn] and carboxylate exudation. Moreover, because of the widespread occurrence of high leaf [Mn] across multiple families in the HDM, this proxy warrants further cross-family investigation. Many of the native plant species, including several putative mycorrhizal species in the HDM region, likely exhibit a P-mining carboxylate releasing strategy.
年，卷(期)：
2026, 8(3)
在线出版日期：
2026年9月11日
