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Registro Completo |
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Biblioteca(s): |
Embrapa Cerrados. |
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Data corrente: |
05/10/2010 |
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Data da última atualização: |
02/08/2013 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
LAVRES JUNIOR, J.; SANTOS JUNIOR, J. de D. G. dos; MONTEIRO, F. A. |
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Afiliação: |
JOSÉ LAVRES JUNIOR, CENA/USP; JOÃO DE DEUS GOMES DOS SANTOS JUNIOR, CPAC; FRANCISCO ANTONIO MONTEIRO, ESALQ. |
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Título: |
Nitrate reductase activity and spad readings in leaf tissues of guinea grass submitted to nitrogen and potassium rates. |
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Ano de publicação: |
2010 |
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Fonte/Imprenta: |
Revista Brasileira de Ciência do Solo, v. 34, p. 801-809, 2010. |
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Idioma: |
Inglês |
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Conteúdo: |
Nitrogen and K deficiency are among the most yield limiting factors in Brazilian pastures. The lack of these nutrients can hamper the chlorophyll biosynthesis and N content in plant tissues. A greenhouse experiment was carried out to evaluate the relationship among N and K concentrations, the indirect determination of chlorophyll content (SPAD readings), nitrate reductase activity (RNO3 -) in newly expanded leaf lamina (NL) and the dry matter yield for plant tops of Mombaça grass (Panicum maximum Jacq.). A fractionated 52 factorial design was used, with 13 combinations of N and K rates in the nutrient solution. The experimental units were arranged in a randomized block design, with four replications. Plants were harvested twice. The first harvest occurred 36 days after seedling transplanting and the second 29 days after the first. Significance occurred for the interaction between the N and K rates to SPAD readings and to RNO3 - assessment taken on the NL during the first growth. Besides, RNO3 - and SPAD readings increased only with the NL N concentration, reaching the highest values of both variables up to about 25 g kg-1, but were ratively constant at higher leaf N. Significant relationships either between SPAD readings or RNO3 - activity and shoot dry mass weight were also observed. The critical levels of N concentration in the NL were, respectively, 22 and 17g kg-1 in the first and second harvest. Thus, SPAD instrument and RNO3 assessment can be used as complementary tools to evaluate the N status in forage grass. MenosNitrogen and K deficiency are among the most yield limiting factors in Brazilian pastures. The lack of these nutrients can hamper the chlorophyll biosynthesis and N content in plant tissues. A greenhouse experiment was carried out to evaluate the relationship among N and K concentrations, the indirect determination of chlorophyll content (SPAD readings), nitrate reductase activity (RNO3 -) in newly expanded leaf lamina (NL) and the dry matter yield for plant tops of Mombaça grass (Panicum maximum Jacq.). A fractionated 52 factorial design was used, with 13 combinations of N and K rates in the nutrient solution. The experimental units were arranged in a randomized block design, with four replications. Plants were harvested twice. The first harvest occurred 36 days after seedling transplanting and the second 29 days after the first. Significance occurred for the interaction between the N and K rates to SPAD readings and to RNO3 - assessment taken on the NL during the first growth. Besides, RNO3 - and SPAD readings increased only with the NL N concentration, reaching the highest values of both variables up to about 25 g kg-1, but were ratively constant at higher leaf N. Significant relationships either between SPAD readings or RNO3 - activity and shoot dry mass weight were also observed. The critical levels of N concentration in the NL were, respectively, 22 and 17g kg-1 in the first and second harvest. Thus, SPAD instrument and RNO3 assessment can be used as complementary tool... Mostrar Tudo |
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Palavras-Chave: |
Guinea Grass; Pasture. |
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Thesagro: |
Clorofila; Estado Nutricional; Gramínea Forrageira. |
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Thesaurus Nal: |
chlorophyll; nitrogen; nutritional status; potassium. |
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Categoria do assunto: |
-- |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/86935/1/lavres-junior-J-01-2010.pdf
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Marc: |
LEADER 02298naa a2200253 a 4500
001 1863616
005 2013-08-02
008 2010 bl uuuu u00u1 u #d
100 1 $aLAVRES JUNIOR, J.
245 $aNitrate reductase activity and spad readings in leaf tissues of guinea grass submitted to nitrogen and potassium rates.
260 $c2010
520 $aNitrogen and K deficiency are among the most yield limiting factors in Brazilian pastures. The lack of these nutrients can hamper the chlorophyll biosynthesis and N content in plant tissues. A greenhouse experiment was carried out to evaluate the relationship among N and K concentrations, the indirect determination of chlorophyll content (SPAD readings), nitrate reductase activity (RNO3 -) in newly expanded leaf lamina (NL) and the dry matter yield for plant tops of Mombaça grass (Panicum maximum Jacq.). A fractionated 52 factorial design was used, with 13 combinations of N and K rates in the nutrient solution. The experimental units were arranged in a randomized block design, with four replications. Plants were harvested twice. The first harvest occurred 36 days after seedling transplanting and the second 29 days after the first. Significance occurred for the interaction between the N and K rates to SPAD readings and to RNO3 - assessment taken on the NL during the first growth. Besides, RNO3 - and SPAD readings increased only with the NL N concentration, reaching the highest values of both variables up to about 25 g kg-1, but were ratively constant at higher leaf N. Significant relationships either between SPAD readings or RNO3 - activity and shoot dry mass weight were also observed. The critical levels of N concentration in the NL were, respectively, 22 and 17g kg-1 in the first and second harvest. Thus, SPAD instrument and RNO3 assessment can be used as complementary tools to evaluate the N status in forage grass.
650 $achlorophyll
650 $anitrogen
650 $anutritional status
650 $apotassium
650 $aClorofila
650 $aEstado Nutricional
650 $aGramínea Forrageira
653 $aGuinea Grass
653 $aPasture
700 1 $aSANTOS JUNIOR, J. de D. G. dos
700 1 $aMONTEIRO, F. A.
773 $tRevista Brasileira de Ciência do Solo$gv. 34, p. 801-809, 2010.
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