RICE SCIENCE

• Research Paper • Previous Articles     Next Articles

Effect of Grain Position within a Panicle and Variety on As, Cd, Cr, Ni, Pb
Concentrations in japonica Rice

CHENG Wang-da 1,2, ZHANG Guo-ping 1 , YAO Hai-gen 2, TANG Mei-ling 2   

  1. 1 Department of Agronomy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou 310029, China; E-mail:
    chwd228@ yeah.net; 2 Jiaxing Academy of Agricultural Sciences, Jiaxing 314016, China
  • Received:2005-01-31 Revised:1900-01-01 Online:2005-03-28 Published:2005-03-28
  • Contact: ZHANG Guo-ping

Abstract: Two japonica rice varieties, a compact panicle (CP) Xiushui 63 and a loose panicle (LP) Xiushui 11 were grown in a slightly
contaminated paddy field, to determine the effect of grain positions within a panicle and variety on grain As, Cd, Cr, Ni and Pb
concentrations. There was a significant difference in grain As, Cd, Cr, Ni and Pb concentrations among grain positions, and the extent
of the difference was variety- and metal-specific; Xiushui 63 showed greater difference than Xiushui 11, and As, Cd, Cr and Pb being
greater than Ni. The top grains (TG) of a panicle had higher As, Cd and Ni concentrations than the middle ones (MG), and the bottom
ones (BG) contained the lowest. With regard to Cr and Pb, the case was opposite. Significantly positive correlations were found
between grain weight and As, Cd, Ni concentrations, but there was a negative correlation between grain weight and Cr, and Pb
concentrations. There was a remarkable variation in grain filling pattern among grains within a panicle, and between Xiushui 63 and
Xiushui 11. In comparison with MG and TG, BG had the lowest grain filling rate and grain weight, leading to obvious difference in grain
weight among grains within a panicle, and a greater difference for Xiushui 63 than for Xiushui 11. The regression analysis showed that
grain As and Cd concentrations were positively correlated with the maximum grain filling rate (GRm),while negatively correlated with
the required time for reaching the maximum grain filling rate (Tpoi). Concerning Cr and Pb, the case was just reverse. It is suggested
that As and Cd accumulation in grains might be accompanied by the carbohydrate accumulations, while Cr and Pb accumulation
displayed a different pattern.

Key words: rice (Oryza sativa), grain position, heavy metal, grain weight, grain filling