Effect of Low Phosphorus Stress on Fe and Mn Absorption and Accumulation by Rice Shoots

In order to investigate the effect of low-P stress on iron and manganese absorption and accumulation by rice genotypes at tillering, booting and maturity stages, pot experiments were conducted using low-P tolerance rice genotypes 508, 580, 99011, 99112 and low-P sensitive rice genotypes 99012 and 99056. The result showed that the difference relative Fe and Mn contents in stems and leaves between the low-P tolerance rice genotypes and low-P sensitive rice genotypes was not obvious. The low-P stress decreased the Fe contents in stems and leaves at the tillering stage of the low-P sensitive rice genotypes larger than those of the low-P tolerance rice genotypes. At the booting stage, the Fe content of only 99056 significantly decreased, while the Mn content significantly decreased except 99112 under the low-P stress. At the maturity stage, the variations in Fe and Mn contents in rice stems and leaves were seen more complicated than those at early growth stages. The Fe and Mn contents in seeds of the low-P tolerance rice genotypes signifi cantly decreased, but those of the low-P sensitive rice genotypes increased. The low-P stress largely decreased the Fe and Mn accumulations in all the rice genotypes, and the accumulations of Fe and Mn were much higher in the P-tolerance rice genotypes than in the P-sensitive rice genotypes at the early growth stages. The difference in accumulations of Fe and Mn in the two rice genotypes declined, but the relative accumulations of Fe and Mn in the P-tolerance rice genotypes increased at the late growth stage. Fig 4, Tab 4, Ref 25