Abstract:

【Objective】In order to reveal the differences in cadmium stress for different rice varieties,【Method】fifty rice varieties with different genetic background were used to analyze the effects of cadmium stress (0 mmol/L, 0.5mmol/L, 0.1 mmol/L, 0.2 mmol/L) on seed germination rate, germination index, vigor index, germ length, radicle length, germ fresh weight and germ dry weight of different rice varieties．【Result】Cd had an increased inhibition to the germination and growth of rice with the increasing cadmium concentration. 0.05 mmol/L cadmium stress had no significant impact on the germination rate and germination index, but it had a significant effect on seed vigor index and the growth of roots and shoots．The inhibitory effects of various cadmium treatments on the radicle of rice seeds were significantly greater than that on their germs. Under 0.1 mmol/L and 0.2 mmol/L cadmium stress, there are highly significant and positive correlation among indexes. Significant differences of cadmium tolerance were noted in different rice varieties.【Conclusion】According to the results of cluster analysis based on the relative value of each trait at germination stage under cadmium stress, the 50 rice varieties were divided into three types: sensitive,intermediate and tolerant．

Key words: cadmium stress, rice, variety, seed, germination period, trait

摘要：

目的为了研究不同水稻品种的镉胁迫抗性差异,为早期预测镉污染,选育镉低积累水稻提供参考。方法采用50个不同遗传背景的水稻品种(系)种子,研究了0(蒸馏水,对照)、0.5、1.0、2.0 mmol/L等4种不同镉浓度胁迫对不同水稻品种种子发芽率、发芽指数、活力指数、胚芽长、胚根长、胚芽鲜质量与胚芽干质量等性状的影响。结果镉胁迫对水稻种子的萌发及幼苗生长具有抑制作用,且随着镉胁迫浓度的增高,抑制作用逐渐加强。0.5 mmol/L Cd²⁺胁迫浓度对各水稻品种种子的发芽率和发芽指数影响不显著,而对其种子活力指数、胚根与胚芽生长则具有显著的抑制作用;不同镉胁迫浓度对水稻种子胚根的抑制作用明显大于胚芽;1.0 mmol/L和2.0 mmol/L Cd²⁺两种胁迫浓度处理下,不同水稻品种种子萌发期的各性状指标间差异达极显著水平,且达到极显著正相关。不同水稻品种对不同镉胁迫浓度的耐性存在明显差异。结论根据不同水稻品种萌发期不同镉胁迫浓度处理的各性状指标与对照的相对值进行聚类分析,可将50个供试水稻品种(系)分为镉胁迫敏感型、中间型和耐受型等3种类型。

关键词: 镉胁迫, 水稻, 品种, 种子, 萌发期, 性状