Multi-nutrient stoichiometry of Chinese hickory (Carya cathayensis) saplings: plant organs vary in their response to nitrogen fertilization.
Multi-nutrient stoichiometry of Chinese hickory (Carya cathayensis) saplings: plant organs vary in their response to nitrogen fertilization.
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DOI：
10.1093/treephys/tpac030
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发表时间：
2022-03
期刊：
影响因子：
4
通讯作者：
Hongtao Xie;Xue-qin Li;Yu-dan Tang;Lauren S. Pile Knapp;Songheng Jin
中科院分区：
文献类型：
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作者：
Hongtao Xie;Xue-qin Li;Yu-dan Tang;Lauren S. Pile Knapp;Songheng Jin
在管理林中，过量施肥导致的氮(N)积累会在多个尺度上影响生物地球化学循环，但我们对N的有效性如何改变器官(根、茎和叶)内和器官之间的多种营养化学计量(包括常量营养素：N、P、K、Ca、Mg和微量营养素：Mn、Fe、Zn)的了解仍然有限。为了解不同器官对施氮反应的化学计量平衡差异，通过水培六水平供氮试验，研究了2年生山核桃幼树的茎生长、根、茎和叶中多种养分的浓度和化学计量比。结果表明，施氮显著提高了叶长、叶宽、地径和幼树高度。施氮量的增加也显著改变了根、茎和叶中的多种养分浓度。在器官内，大量营养素的反应通常比微量营养素更积极。在各器官中，叶和茎对氮素供应的反应普遍比根积极。不同器官中养分的化学计量比随施氮量的增加而发生显着变化，但变化的方向和程度因器官而异。特别是，增加氮素供应降低了植物器官中大量和微量营养素与氮的比率，而增加氮素供应则提高了磷与其他养分的比率。施氮后，叶片和茎中微量营养元素的比例降低，而根中的比例增加。叶N和茎锰化学计量学对氮素有效性的反应强烈，表明促进了N的吸收，但降低了Mn2+积累过量N的风险。总体而言，山核桃幼苗在茎生长方面对增加N有效性做出积极反应，但多种营养的化学计量学动态平衡明显依赖于器官。这些结果有望在器官水平上加深我们对氮素诱导的多种营养物质动态平衡变化的理解，并可能为植物如何适应增加的氮肥施用量提供新的见解。
Nitrogen (N) enrichment from excessive fertilization in managed forests affects biogeochemical cycles on multiple scales, but our knowledge on how N availability shifts multi-nutrient stoichiometries (including macronutrients: N, P, K, Ca, Mg and micronutrients: Mn, Fe, Zn) within and among organs (root, stem and leaf) remains limited. To understand the difference among organs in terms of multi-nutrient stoichiometric homeostasis responding to N fertilization, a six-level N supply experiment was conducted through a hydroponic system to examine stem growth, multi-nutrient concentrations and stoichiometric ratios in roots, stems and leaves of two-year-old Chinese hickory (Carya cathayensis) saplings. Results showed that N supply significantly enhanced leaf length, width, basal diameter and sapling height. Increasing rates of N also significantly altered multi-nutrient concentrations in roots, stems and leaves. Macronutrients generally responded more positively than micronutrients within organs. Among organs, leaves and stems generally responded more actively to N supply than roots. The stoichiometric ratios of nutrients within different organs changed significantly with N supply but their direction and degree of change varied by organ. Specifically, increased N supply reduced the ratios of both macronutrients and micronutrients to N in plant organs while increased N supply elevated the ratios of P to other nutrients. With N fertilization, ratios of micronutrients decreased in leaves and stems and increased in roots. In particular, leaf N and stem Mn stoichiometries responded strongly to N availability, indicating stimulated N uptake but decreased risk of Mn2+ accumulation to excessive N. Overall, Chinese hickory saplings responded positively to increasing N availability in terms of stem growth, but the multi-nutrient stoichiometric homeostasis were distinctively organ-dependent. These results are expected to enhance our understanding of N-induced changes in nutrient homeostasis of multiple nutrients at the organ level and may offer new insights into how plants adapt to increasing N fertilization.