Species-specific nitrogen resorption proficiency in legumes and nonlegumes
Species-specific nitrogen resorption proficiency in legumes and nonlegumes
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DOI：
10.1007/s10265-020-01211-1
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发表时间：
2020-07
影响因子：
2.8
通讯作者：
Shimpei Oikawa;Yusuke Matsui;Michio Oguro;M. Okanishi;Ryo Tanabe;Tomoki Tanaka;Ayaka Togashi;T. Itagaki
中科院分区：
文献类型：
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作者：
Shimpei Oikawa;Yusuke Matsui;Michio Oguro;M. Okanishi;Ryo Tanabe;Tomoki Tanaka;Ayaka Togashi;T. Itagaki
衰老叶片对氮的吸收使植物能够重新利用氮，从而减少对当前环境中氮吸收的依赖。因此，氮的吸收对植物的生存和适应具有重要意义，特别是对低氮条件下生长的植物。我们研究了日本温带地区25种豆科植物和25种非豆科植物衰老叶片的氮吸收，以验证豆科植物对大气N2的高吸收尚未进化的假设。氮素吸收的程度是通过氮素吸收能力来量化的，氮素吸收能力是用衰老过程中叶片氮浓度降低的程度来衡量的，即衰老的叶片氮浓度越低，叶片脱落的氮素损失越低，氮素吸收能力越高。为支持这一假设，豆科植物衰老叶片氮浓度高于非豆科植物，但组间存在相当大的重叠。豆科植物衰老叶片氮浓度越高，衰老过程中叶片氮吸收率越低，尤其是叶片氮浓度较高的品种。根据等级划分分析，物种对衰老叶片氮浓度总方差的贡献较大，而功能群（豆科/非豆科）的贡献较小。本研究表明，豆科植物并不擅长从衰老叶片中吸收氮，但固氮可能不是氮吸收的唯一最重要决定因素。
Nitrogen (N) resorption from senescing leaves enables plants to reuse N, thereby making them less dependent on current N uptake from the environment. Therefore, N resorption is important for survival and fitness, particularly for plants growing under low N supply. We studied N resorption from senescing leaves of 25 legumes and 25 nonlegumes in a temperate region of Japan to test the hypothesis that high N resorption has not evolved in legumes that fix atmospheric N2. The extent of N resorption was quantified by N resorption proficiency that is measured as the level to which leaf N concentration was reduced during senescence, i.e., the lower the senesced leaf N concentration, the lower the N loss through leaf fall and higher the N resorption proficiency. In support of the hypothesis, senesced leaf N concentration was higher in legumes than in nonlegumes, but there was considerable overlap between the groups. The higher senesced leaf N concentration of legumes was associated with a lower proportion of leaf N resorbed during senescence, particularly in species with higher leaf N concentrations. According to a hierarchical partitioning analysis, there was a large contribution of species to the total variance in the senesced leaf N concentration as opposed to a minor contribution of functional group (legume/nonlegume). This study reveals that legumes are not proficient at resorbing N from senescing leaves but that N2-fixation might not be the single most important determinant of N resorption.