The preference of nitrate uptake in Chinese prickly ash estimated by δ15N values and cation concentrations

Autor: She-Hong Li, He-Chun Piao, Si-Liang Li, Shijie Wang
Rok vydání: 2017
Předmět:
Zdroj: Environmental Earth Sciences. 76
ISSN: 1866-6299
1866-6280
DOI: 10.1007/s12665-017-6407-1
Popis: The nitrogen isotopic compositions of plant tissue could reflect its uptake of and preference for ammonium or nitrate. However, various factors may influence the field-collected δ15N values under field condition, which causes the interpretation problematic. The spatial variation of nitrogen (N) concentrations and the isotopic compositions were investigated in the soils and tissues of Chinese prickly ash from the southwest China to the east China. The objectives were to investigate the variation in soil and tissue δ15N values and N forms taken up by the plant. The leaf and root δ15N values varied significantly in response to the pattern of soil δ15N values. The difference in δ15N values between the leaves and roots was 2.57‰ and may be caused by an increase in the transport of unassimilated $$ {\text{NO}}_{3}^{ - } $$ and $$ {\text{NH}}_{4}^{ + } $$ to the leaves. Leaf nitrogen was significantly and positively correlated with leaf potassium and negatively related to leaf calcium. Because potassium is the favoured counter-cation for nitrate transport in the xylem, the enrichment of 15N in leaf relative to root induced by preferenced uptake of nitrate should be accompanied by significant and positive relationship of leaf nitrogen with leaf potassium concentrations. These results suggest that Chinese prickly ash prefers $$ {\text{NO}}_{3}^{ - } $$ over $$ {\text{NH}}_{4}^{ + } $$ .
Databáze: OpenAIRE
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