Can iron and zinc in rice grains (Oryza sativa L.) be biofortified with nitrogen fertilisation under pot conditions?

BACKGROUND: Because only grain yield has been investigated, the influence of fertilisation by N on the concentration of Fe and Zn in polished rice has been overlooked in China. So, using the rice cultivars of the indica Zhenong 952 and the japonica Bing 98110, pot experiments were conducted to investigate the amounts of N fertiliser (applied as urea at rates of 0, 0.50, 1.00 and 1.50 g N pot(-1)) that would lead to the optimum Fe and Zn concentrations in polished rice as well as grain yield. RESULTS: For Zhenong 952, the optimal Fe and Zn concentration as well as grain yield was attained at a N application of 1.00 g pot(-1); for Bing 98110 the optimum N was 1. 50 g pot(-1). The ratio of Zn deposited in brown rice was about 40% of the total Zn in the plant irrespective of N application. However, Fe was only about 3%. Fe concentration in brown rice was approximately one-half of the rice husk, one-fifth of the peduncles, and one-tenth of the leaves, and a little more than 1% of the root. CONCLUSION: The optimum N application, alone, on rice crops could increase Fe concentration in polished rice, but had an adverse effect for Zn. Fe appeared not to be as easily accumulated into rice seeds as was Zn. (C) 2008 Society of Chemical Industry.