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Intra-specific variation in pea responses to ammonium nutrition leads to different degrees of tolerance
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Orientador(es)
Resumo(s)
The form of nitrogen nutrition affects many biochemical and physiological processes in plants, leading to
markedly different growth responses. Many plant species have been characterized asammoniumtolerant
or sensitive. The objective of this work was to assess the range of physiological adaptative responses
involved in tolerance of ammonium nutrition at the intra-specific level.
Pisum sativum L. was selected as a model of tolerance for the study, and four varieties of agricultural
importance (Snap-pea, Rondo, Tristar and Eclipse) were grown hydroponically withammoniumor nitrate
(0.5, 2.5, 5.0 and 10.0mM)as the sole nitrogen source. Physiological parameters including photosynthesis,
respiration and ammonium contents were analyzed. Activities/expression of key enzymes of the nitrogen
metabolism was also determined, for which novel antibodies against glutamate dehydrogenase and
glutamine synthetase were obtained.
Snap-pea was considered a reference plant for ammonium tolerance, since its biomass accumulation
was not affected by nitrogen source. It avoided the physiological effects of ammonium through low
growth potential, high respiratory rates and activity of the alternative pathway. A multivariate analysis
of the results showed that each of the four varieties had distinct adaptative responses to ammonium
nutrition, highlighting the flexibility of response to ammonium nutrition at the species level. A general
activation of glutamate dehydrogenase (GDH) was observed, regardless of the degree of tolerance to
ammonium, which may be due to GDH being part of a common stress response to carbon deficit rather
than an ammonium tolerance mechanism.
Descrição
ACESSO via B-on: http://dx.doi.org/ doi:10.1016/j.envexpbot.2010.09.014
Palavras-chave
Ammonium nutrition Ammonium tolerance Ammonium stress Glutamate dehydrogenase Glutamine synthetase Pisum sativum L.
Contexto Educativo
Citação
Environmental and Experimental Botany 70 (2011) 233–243