杂交水稻不同器官镉浓度与累积量

以生长于盆钵中的两系杂交稻两优培九、扬两优6号和103S/郑粳2号及三系杂交稻丰优香占、K优818和汕优63为材料，移栽前盆土内加入镉（Cd），使土壤Cd浓度为100 mg/kg，研究水稻植株不同器官Cd的浓度和累积量。与未加Cd的对照相比，Cd处理降低了两优培九和103S/郑粳2号的产量，其主要原因是每穗粒数减少，而对其余组合的产量无显著影响。水稻植株对Cd吸收及分配存在着基因型差异，以汕优63累积量最多，K优818累积量最少。水稻植株不同器官Cd的浓度和累积量的大小顺序为根>茎鞘>叶片。籽粒不同部位Cd的浓度大小顺序为糠层>颖壳>精米。精米中Cd累积量仅为谷粒Cd累积量的30%左右。在抽穗期和成熟期,同一器官Cd浓度及累积量呈显著或极显著正相关，但不同器官之间的相关不显著。在6个供试的杂交稻组合中，精米中Cd的浓度以扬两优6号最高，K优818最低。对不同杂交稻组合植株中Cd浓度和累积量差异的原因进行了讨论。

Concentrations and Accumulation of Cadmium in Different Organs of Hybrid Rice

Six hybrid rice combinations including Liangyoupeijiu, Yangliangyou 6, 103S/Zhengjing 2, Fengyouxiangzhan, Kyou 818 and Shanyou 63 were used in the pot experiments. Cadmium(Cd)was added into pots before rice transplanting and the concentration of Cd in pot soil was 100 mg/kg. The concentration and accumulation of Cd in different plant organs were measured. Compared with the control (no Cd was added), Cd addition significantly reduced the grain yield of Liangyoupeijiu and 103S/Zhengjing 2 mainly due to the reduction of spikelet number per panicle. There was no significant difference in the grain yield between the control and the Cd treatment for the other hybrid combinations. Significant differences in uptake and distribution of Cd were observed among the six combinations, with Shanyou 63 having the highest and Kyou 818 the lowest Cd accumulation in plants. Concentration or accumulation of Cd in various plant organs was in the order of root>culm and sheath >leaf, and Cd concentration in a grain was in the order of bran >hull>milled rice. Cd in milled rice was about 30% of total amount of Cd accumulated in grain. The concentration and accumulation of Cd in the same organ at the heading and maturity stages were positively and significantly correlated, but the correlation was not significant between different organs. Among the six tested hybrids, Yangliangyou 6 contained the highest, and Kyou 818 the lowest Cd concentration in milled rice. The reasons for variations of Cd concentration and accumulation in plants among the hybrids were also discussed.