Abstract

BREVEDAN1, RE et al. Phosphorus nutrition on nitrogen metabolism of non-nodulated soybean. Phyton (B. Aires) [online]. 2009, vol.78, n.1, pp.49-52. ISSN 1851-5657.

Two experiments were conducted under greenhouse conditions to study the influence of P deficiency on nitrogen nutrition of non-nodulated soybean. There was a reduction of N and P content in P deficient (P-) plants of almost 50% after 50 days. During this period, dry matter of these plants was reduced by 33%. Nitrate reductase activity and shoot nitrate content were lower in P than in P+ plants. Seventy five percent of nitrates in P- plants were in the roots. Nitrate accumulation in roots would be due to the lower nitrate reductase activity in this organ and a reduced water flux to shoots. Root nitrate concentration increases would cause a negative feedback which would reduce plant nitrate uptake.

Keywords : Phosphorus deficiency; Nitrate reductase; Nitrate uptake; Nitrate translocation; Phosphorus-nitrogen interactions.

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