Combined effect of rice genotypes and soil characteristics on iron plaque formation related to Pb uptake by rice in paddy soils
Journal
Journal of Soils and Sediments
Journal Volume
16
Journal Issue
1
Pages
150-158
Date Issued
2016
Author(s)
Abstract
Purpose: The formation of iron plaques and their ability to sequester heavy metals are influenced by soil properties and rice genotype. Lead accumulation in paddy soil is increasing, but in order to assess soil suitability for rice cultivation, a better understanding of the effects of iron plaques on Pb uptake by paddy rice is needed. Materials and methods: Two rice cultivars, Taikang 16 (TK16) and Taichung Sen 10 (TCS10), were grown in pots to assess lead (Pb) uptake. Three paddy soils (C, D, and N) sampled from potentially contaminated sites in central Taiwan were used for the experiment, with additional Pb spiking (0, 150, and 300 mg kg−1). Results and discussion: Pb uptake by rice plants was positively correlated with soil Pb availability. However, Pb uptake by rice plants in soils D and N, even with higher Pb availability, was much less than in soil C. We attribute this to the large amount of iron plaques coating the root surfaces of plants in soils D and N. Moreover, TCS10, which is an indica rice sensitive to metal stress, took up more Pb than TK16, which is a japonica rice. Iron plaque formation on the roots of TK16 was superior to that on the roots of TCS10. Conclusions: Iron plaque formation that inhibits Pb uptake appears to be driven primarily by the soil properties and secondarily by the rice genotype. Nevertheless, the capacity of iron plaques to sequester Pb is limited by a high level of Pb contamination in the soil.
Type
journal article