Molecular-level carbon traits of fine roots: unveiling adaptation and decomposition under flooded conditions

作者：Mengke Wang, Peng Zhang, Huishan Li, Guisen Deng, Deliang Kong, Sifang Kong, Junjian Wang · 发表于：Biogeosciences · 年份：2024 · DOI：10.5194/bg-21-2691-2024 · 被引用次数：4 · 研究领域：Plant responses to water stress、Coastal wetland ecosystem dynamics、Plant nutrient uptake and metabolism

Fine roots are vital for plant development and carbon biogeochemical cycling in terrestrial ecosystems. Flooding is known to regulate the physiology and morphology in plant roots; however, its impact on molecular-level characteristics of carbon compounds (carbon traits) in fine roots remains largely unexplored, which limits our understanding of root adaptation and decomposition under changing environments. Here, we used a sequential extraction method, starting from nonpolar to polar solvents, in order to obtain dichloromethane- and methanol-extractable ( F DcMe ) fractions, base-hydrolyzable ( F KOHhy ) fractions, and CuO-oxidizable ( F CuOox ) fractions from fine roots of Dysoxylum binectariferum , which is naturally grown in soil and water. Subsequently, we characterized them using targeted gas chromatography–mass spectrometry and nontargeted Fourier transform ion cyclotron resonance mass spectrometry. Also, decomposition experiments were conducted on soil- and water-grown roots under aerobic and anoxic conditions. Results showed a consistent increase in the unsaturation degree and aromaticity of the analytes from F DcMe to F CuOox fractions. Both analyses were sufficiently sensitive to show that, compared to soil-grown roots, the water-grown roots developed more polyphenolics with a high unsaturation degree and aromaticity and had more nonstructural compositions. Furthermore, although flooding provided an anoxic condition that slowed down root decomposition, the adaptive s...