Ameliorating effect of potassium on iron toxicity in hybrid rice
钾减轻杂交稻铁毒

Toxicity of Fe2+ has been a constraint to lowland rice production, potassium has the ameliorating effect on Fe2+ toxicity .Hybrid rice (Oryza sativa L.) were grown in nutrient solution with three K supplies (0.26, 0.51 and 1.02 mmol/L) and five Fe2+ levels (0.09, 0.18, 0.36, 0.54, and 0.90 mmol/L). Excessive Fe2+ greatly decreased root and shoot dry weights, root length, and shoot height of the hybrid rice, and this depression was obvious even at relatively low Fe2+ levels (above 0.18 mmol/L). Excessive Fe2+ levels notably influenced morphological parameters and concentrations of K, P, and N in the plants. High K supplies ameliorated the negative effects of higher Fe2+, as indicated by increases in biomass and nutrient contents. Proper K supply reduced translocation of Fe2+ from roots to shoots, especially to the upper leaves. Phosphorus, which is antagonistic to Fe2+, was significantly increased by K supply. Ameliorating effects of K may be attributed to the antagonistic effect of K on Fe absorption and translocation to shoots, especially to upper leaves, and to the improvement of plant nutritional status.