Nitrate reductase activity in field-grown pueraria lobata (Kudzu) in southeastern Brazil.

AUTOR(ES)
FONTE

Pesquisa Agropecuaria Brasileira

DATA DE PUBLICAÇÃO

2011

RESUMO

Although Pueraria lobata (Willd.) Ohwi (P. thunbergiana) (Sieb. & Zucc.) Benth.) is thus ecologically and economically important in much to world, its physiological ecology and other factor contributing to its invasive growth are not well understood. Nitrate reductase activity (NRA) measurements have long been used to indicate the effect of changes in the environment on a plant's capacity to assimilate nitrate nitrogen. The objective of this paper was to describe how naturally occurring changes in air temperature (Ta) and solar radiation flux density (St), affect the in vivo nitrate reductase activity in field-grown P. lobata and consequently the ability of this species to assimilate nitrate nitrogen in non-native areas. A meteorological thermometer and a thermocouple pyranometer were used to measure changes in the air temperature and the solar radiation flux density, respectively. The highest nitrate reductase activity found in this study [5.8 umol NO2 h-1 (gFW)-1] was observed when Ta was 27.4 Graus C. A significant reduction in nitrate activity was observed with Ta below 21.8 Graus C. or above 33.6 Graus C. Nitrate reductase activity was linear and positively related to St. A 12% increase in nitrate reductase activity was observed when St, rose from 531 to 852 W m-2. These results suggest that P. lobata can be a successful competitor in regions located at the transition between subtropical and tropical biomes.

ASSUNTO(S)

cultura de cobertura ecofisiologia forragem leguminosae assimiliacao de nitrato cover crop ecophysiology forage nitrate assimilation

ACESSO AO ARTIGO

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