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Improvement of the 15 N dilution method for estimation of absorption of NOx by plants supplied with 15 N‐labelled fertilizer
Author(s) -
QIAO Z.,
MURRAY F.
Publication year - 1998
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1046/j.1469-8137.1998.00887.x
Subject(s) - dilution , nitrate , chemistry , fertilizer , isotope dilution , absorption (acoustics) , nox , nitrogen , zoology , chromatography , biology , mass spectrometry , materials science , physics , organic chemistry , composite material , thermodynamics , combustion
To develop further the methods for estimation of NOx absorption by plants supplied with 15 N‐labelled fertilizer, we proposed a new calculation method, total N fixed method (TNF), and compared with the 15 N dilution method and the classical mass balance method (MB). Hydroponically grown soybean plants were supplied with 15 N‐labelled nitrate and exposed to 200–250 nl l −1 NO 2 for 7 d. The proportions of the N derived from NO 2 to total N in exposed plants were estimated by the three methods. The reported rates of NO 2 absorption by several plant species, estimated by the 15 N dilution method, were recalculated using the TNF method. The results of the two methods were compared and showed that: (1) The 15 N dilution method overestimated the content of NO 2 ‐N in exposed plants compared with the MB method whilst the TNF method produced estimations of NO 2 ‐N closer to those by the MB method when the plants were supplied with 5 m M nitrate. (2) The differences in estimations between the MB method and either the 15 N dilution method or the TNF method increased with decreasing supply of 15 N‐labelled nitrate to roots.