INVESTIGADORES
PIECKENSTAIN Fernando Luis
congresos y reuniones científicas
Título:
Ontogenic changes in nitrogen and ammonium and ureide metabolism in Phaseolus vulgaris root nodules
Autor/es:
LLUCH C, JA HERRERA-CERVERA, F PIECKENSTAIN & N TEJERA
Lugar:
Seattle, USA
Reunión:
Congreso; Annual Meeting of the American Society of Plant Biologists; 2005
Institución organizadora:
American Society of Plant Biologists
Resumen:
Phaseolus vulgaris is the most important food legume for human consumption worldwide. Symbiotic nitrogen fixation (SNF) potential in common beans is considered to be low in comparison with other legumes. The impact of four phosphate doses (0, 0.05, 1.5 and 5.0 mM9, applied to the nutrient solution, on growth, nitrogen fixation and enzymes activities of ammonium, ureides and phosphorous metabolisms was investigated at different plant stages. Higher P doses (1.5 and 5 mM) increased plant biomass at different harvests, however maximum values were reached at reproductive period. This result was significantly correlated with the behaviour observed for the leaf area. Likewise these P treatments also induced an increase on nodule number and nodule dry weight and consequently stimulated the total acetylene reduction activity per plant. Maximum nitrogen requirements in common beans were obtained at the end of the vegetative growth as evidenced by the increase on the nitrogenase activity. Nitrogen metabolisms enzymes (GS/GOGAT) were not affected by the P deficiency in all stages tested. As observed for the nitrogenase activity, highest GS/GOGAT activities were also found at the vegetative stage. Neither and stimulatory effect on ureides enzymatic activities (xanthine DH, uricase and aspartate amine transferase) by P treatment was observed. On the other had, acid phosphatase on nodules was highly stimulates by P deficiency, mainly on the flowering period (27 days after sowing). On addition ATP content in nodule and root, and nitrogen and phosphorous concentration in shoot and root augmented with exogenous P application. Our results suggested that 1.5 mM is an adequate P dosage for development of Phaseolus vulgaris growing under symbiotic conditions.