Método simplificado para determinação de nitrato, nas fôlhas, com o ácido fenoldissulfônico1 1 Trabalho feito com ajuda da Fundação Rockefcller, U.S.A,, e do Instituto Brasileiro do Café, através de seu Grupo Executivo de Racionalização da Cafeicultura (GERCA). Recebido para publicação em 21 de setembro de 1964.
Simplified procedure for nitrate determination in leaves, with phenoldisulfonic acid
J. Romano Gallo; W. L. Lott.
SUMMARY
Leaf analyses for nitrate-nitrogen in petioles (cotton, potato) and midribs (corn, sugar cane) and in the whole leaf (coffee) are being studied as a method for evaluating the nitrogen status oi these plants.
Because of its sensitivity and accuracy the nitrophenol-disulfonic-yellow color reaction was used to determine nitrates in plant material, the procedure being largely adapted from the work of Johnson and Ulrich (3). The procedure as described here is suitable for leaf samples in the absence of excess chloride.
The present method differs from the previous work in the extraction of nitrate for certain samples that give highly colored plant extracts. Clear extracts from coffee leaves are obtained by use of copper sulfate, calcium hydroxide, and magnesium carbonate, with details taken from the procedure for clarifying and decolorizing soil extracts described by Chapman and Pratt (4) and Jackson (5).
Data of Table 1 show the precision obtained on leaf samples at different levels of nitrate.
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Datas de Publicação
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Publicação nesta coleção
19 Fev 2010 -
Data do Fascículo
1965
