Enrichment of Heavy Metals by Different Varieties of Rice

Abstract

Pot experiment was carried out to compare the difference of Cr accumulation and distribution in different organs of 3 rice cultivars under different treatment of Cr. The results showed that the average values of Cr concentration in root, stem, leaf, chaff and grain of all cultivars were 7.63~141.09, 2.29~8.58, 14.01~39.93, 3.65~5.21 and 0.46~0.92 mg•kg-1, respectivly. Compared with the control, the accumulation and translocation of Cr in rice was significantly affected by the stress of exogenous Cr. At control treament, most of Cr was distributed in leafs, but the proportion of Cr in roots was significantly increased under the stress of exogenous Cr. At the same Cr application rate level, the distribution of Cr in II You-838 and Yixiangyou-10 followed the pattern: root > leaf > chaff > stem > grain, while it showed root > leaf > stem > chaff > grain in Jinfuyou-270. The distribution of Cr in different parts of rice was very uneven for three rice cultivars. With increasing Cr treatment levels, the proportion of Cr in roots was increasing, while a decrease was observed in aerial parts, and their bioconcentration factors (BCF) and translocation factors (TF) of Cr also declined. The transport ability of Cr from root to leaf was stronger, but weak ability in translocating Cr from root to stem, chaff and grain. There were different in Cr accumulation and distribution in organs of 3 rice cultivars. The falling sequence of accumulation and translocation ability of Cr in rice was Jinfuyou-270 > Yixiangyou-10 > II You-838. The Cr concentration in the grain of Jinfuyou-270 was 0.70~0.92 mg•kg-1, which was quite close to the national food heavy metal limits hygienic standard.