植物吸收土壤有机氮的研究进展

传统的氮循环模式认为,土壤有机氮只有经过微生物分解转化为无机氮(NH₄⁺+NO₃^-)后才能为植物吸收利用。然而,近年来许多研究证实多种陆地植物具有从土壤中获取小分子有机物质(如自由态氨基酸)的能力,对传统的氮循环模式形成巨大的挑战。论文从土壤中氮素的形态、植物吸收有机氮的证据、有机氮吸收的机制、以有机氮为重要氮源的生态系统类型以及根系吸收与分泌有机氮之间的平衡等5个方面进行了综述,分析了当前研究方法的优缺点,针对本领域内核心科学问题,提出了未来植物吸收有机氮的改进方法及研究方向,为进行植物利用有机氮的研究提供方法基础。

Advances in Studies on Organic Nitrogen Uptake by Terrestrial Plants

Traditional concept of nitrogen cycling in terrestrial ecosystems has assumed that organic nitrogen can be used by terrestrial plants only after it is decomposed by soil microorganisms into inorganic nitrogen (NH₄⁺+NO₃^-). Recent studies have confirmed that a variety of plant species have the capacity to take up soil organic nitrogen in the form of low molecular weight substances, e.g. free amino acids, challenging the core of the traditional concept of nitrogen cycling. We here reviewed major advances made in the studies of organic nitrogen uptake by plants from five aspects: nitrogen forms in soil, evidence of organic nitrogen uptake by plants, mechanisms responsible for organic nitrogen uptake by plants, main plants and ecosystems with importance of organic nitrogen uptake and the balance between exudates and uptake of organic nitrogen by roots. We also assessed advantages and limits of research approaches. According to the central question within this research field, we suggested several directions we should focus on in future studies. We call for new research for a better understanding of organic nitrogen uptake by plants.