Different relationships of fine root traits with root ammonium and nitrate uptake rates in conifer forests
Different relationships of fine root traits with root ammonium and nitrate uptake rates in conifer forests
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DOI：
10.1080/13416979.2022.2102752
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发表时间：
2021-11
影响因子：
1.5
通讯作者：
Tatsuwo Ito;Ayumi Tanaka‐Oda;Taiga Masumoto;Maiko Akatsuki;N. Makita
中科院分区：
文献类型：
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作者：
Tatsuwo Ito;Ayumi Tanaka‐Oda;Taiga Masumoto;Maiko Akatsuki;N. Makita
树木细根对氮的吸收是了解根系生理功能的重要基础。然而，直接调查原位铵和硝酸盐的吸收率是有限的。因此，我们的目的是澄清树种之间的无机氮吸收速率，并确定控制氮吸收的因素，通过与细根性状在冷温带针叶林。采用溶液耗竭法研究了完整根系对NH 4+和NO3 -的吸收速率与根径、比根长和根组织密度的关系。在这项研究中，针叶类植物的根更喜欢NH 4+而不是NO3 −。在不同物种中，NH 4+吸收与直径，SRL和RTD之间存在显着关系;相反，只有RTD对NO3 −吸收有显着影响。氮素吸收速率与根系形态性状的关系在NH 4+和NO3 -处理间存在差异。我们发现，无机氮的吸收与形态性状的关系取决于通过土壤吸附的N形态的特性和树木的N同化效率。研究结果在理解根系生理功能和预测氮素吸收策略方面取得了突破性进展。
ABSTRACT Nitrogen (N) uptake by fine roots of trees is important for understanding root physiological function in forest ecosystems. However, direct investigations of in situ ammonium and nitrate uptake rates are limited. Thus, we aimed to clarify inorganic N uptake rates among tree species and determine the factors controlling N uptake through relationships with fine root traits in cool temperate coniferous forests. Using a solution depletion method for measuring N uptake, we observed the relationship of N uptake rate in the form of NH4 + and NO3 – by an intact root system with root morphological traits, such as root diameter, specific root length (SRL), and root tissue density (RTD). The coniferous roots in this study preferred NH4 + to NO3 −. Across species, there were significant relationships between NH4 + uptake and diameter, SRL, and RTD; in contrast, only RTD had a significant impact on NO3 − uptake. Relationships between N uptake rates and root morphological traits differed between NH4 + and NO3 –. We found that the relationship of inorganic N uptake with morphological traits depended on the characteristics of the N form adsorbed through soil and on tree N assimilation efficiency. Our results make a breakthrough in the understanding of root physiological function and the prediction of fundamental N acquisition strategies.