摘要： 探索生育后期氮肥施用对水稻镉积累的影响，为稻米镉消减提供技术支持。采用大田小区试验，以杂交稻株两优819（早稻）和常规稻湘晚籼12号（晚稻）为试验材料，设粒肥用量占总氮20%的不同生育期施粒肥处理，分别为始穗期施粒肥（F1）、齐穗期施粒肥（F2）、灌浆期施粒肥（F3）及不施粒肥处理（CK）。试验结果表明，合理施用粒肥可显著提高晚稻籽粒生物量，齐穗期和灌浆期施用粒肥显著提高了早稻籽粒生物量。不同生育期施粒肥对降低籽粒富集系数、镉在植株内转运系数存在显著差异；不同生育期施粒肥水稻成熟期各部位镉含量不同，施粒肥提高了早稻根系和茎叶的镉含量，但显著降低了籽粒镉含量，其值表现为CK > F1 > F3 > F2；晚稻的根系镉含量在始穗期施粒肥处理显著提高，茎叶镉含量均显著大于CK，灌浆期施粒肥处理的籽粒镉含量有小幅度降低；与CK相比，早晚稻籽粒镉含量最大降幅分别为44.87%，22.31%。可知，不同生育期施粒肥对早晚稻籽粒的镉含量影响有差异，齐穗期施粒肥可显著降低早稻籽粒的镉含量，灌浆期施粒肥能降低晚稻籽粒的镉含量。

关键词: 水稻, 籽粒镉含量, 镉积累, 氮肥, 转运系数

Abstract: The aim of the study was to explore the effects of nitrogen fertilizer application on rice cadmium accumulation in late growth stage, and provide technical support for rice cadmium reduction. A field plot experiment was conducted with hybrid rice Zhuliangyou 819 (early rice) and conventional rice Xiangwanxian 12 (late rice) as experimental materials. Grain fertilizer was applied at 20% of total nitrogen at different growth stages, including grain fertilizer at the beginning of heading stage(F1), grain fertilizer at the full heading stage(F2), grain fertilizer at the filling stage(F3), and no grain fertilizer treatment was as CK. The results showed that the application of grain fertilizer significantly increased the grain biomass of late rice, and the application of grain fertilizer at the full heading stage and the filling stage significantly increased the grain biomass of early rice. There were significant differences in reducing grain enrichment coefficient and cadmium translocation coefficient in plants between different growth stages. Cadmium content in different parts of rice was different at different growth stages. The application of grain fertilizer increased cadmium content in roots, shoot of early rice, but significantly decreased cadmium content in grains which the value represented as CK > F1 > F3 > F2. Cadmium content in roots of late rice increased significantly under the treatment of grain fertilizer at the beginning of heading stage. Cadmium content in shoot was significant higher than CK, but it decreased slightly in grain fertilization at grain filling stage. Compared with CK, the maximum reduction of cadmium content in early and late rice grains was 44.87% and 22.31% respectively. The effects of grain fertilizer application at different growth stages on cadmium content in early and late rice grains were different. Grain fertilizer application at full heading stage could significantly reduce cadmium content in early rice grains, and grain fertilizer application at grain filling stage could reduce cadmium content in late rice grains.

Key words: Rice, Grain cadmium content, Cadmium accumulation, Nitrogen fertilizer, Transport coefficient

中图分类号: 

• S511.01