Common Bean Seed Complements Molybdenum Uptake by Plants from Soil

Molybdenum (Mo) reserve in large seeds can complement Mo uptake by plants from soil, but the content of Mo in common bean (Phaseolus vulgaris L.) seed for this purpose is unknown. We hypothesized that 3.639 +/- 0.751 mu g Mo seed(-1) would be sufficient to complement Mo uptake by irrigated common bean plants from a Mo-poor soil. Three field experiments were performed in a clayey Ultisol naturally infested by native strains of Rhizobium in Zonada Mata, Minas Gerais, Brazil. Treatments were arranged as 4 x 2 factorial combination of Mo contents in seeds [small (0.007 +/- 0.007 or 0.248 +/- 0.057 mu g Mo seed(-1)) or large (3.639 +/- 0.751 or 6.961 +/- 1.844 mu g Mo seed(-1))] and Mo spraying treatments (90 g ha(-1) or unsprayed) with six replications. Phosphorus, N (25 kg ha(-1)), and K were applied together in the furrow during planting time. No topdressing N was applied. Final plant population and seed yield were evaluated in two experiments. Molybdenum contents in the seeds did not affect plant population. On average, unsprayed plants from seeds with small Mo contents yielded 1785 kg ha(-1), while those from seeds with large Mo content yielded 2109 kg ha(-1). Foliar application of Mo increased plant N status, plant growth, and yield in plants originated from seeds with small Mo content, but not in plants grown from seeds with large Mo content. We conclude that 3.639 +/- 0.751 mu g Mo seed(-1) sufficiently complement the Mo uptake by common bean plants from soil.