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Diagnosis of nitrogen status in Chinese cabbage ( Brassica rapa chinensis ) using the ratio of amide II to amide I in leaves based on mid‐infrared photoacoustic spectroscopy
Author(s) -
Li Chunyang,
Du Changwen,
Ma Fei,
Zhou Jianmin
Publication year - 2015
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/jpln.201500283
Subject(s) - amide , nitrogen , chemistry , photoacoustic spectroscopy , photoacoustic imaging in biomedicine , fourier transform infrared spectroscopy , analytical chemistry (journal) , brassica rapa , chromatography , organic chemistry , biochemistry , optics , physics , gene
In order to quickly diagnose the nitrogen status of Chinese cabbage ( Brassica rapa chinensis ), Fourier transform mid‐infrared photoacoustic spectroscopy, a nondestructive and rapid approach was used. Two clear stable peaks, in the range 1680–1650 cm −1 associated with amide I and in the range of 1530–1520 cm −1 associated with amide II, were observed and responded positively to nitrogen treatments. The characteristic bands of amide I and amide II were also accurately separated by curve‐fitting via deconvolution using a Gauss expansion function. The ratio of the photoacoustic intensities of amide II to amide I was used for correlation analysis with nitrogen treatment, and the correlation coefficients ( R 2 , n = 59) at seedling and growth stage were 0.9769 ( P ≤ 5%) and 0.9884 ( P ≤ 5%), respectively. The ratio of the amide II and amide I peaks was found to be an indicator of nitrogen input during the seedling stage such that a ratio of less than 0.9 indicated a low nitrogen input, a ratio between 0.9 and 1.0 indicated a moderate nitrogen input, and a ratio of more than 1.0 implied an excessive N input.