三个优质晚稻品种的镉积累分配特性差异分析

Analysis on Difference in Cd Accumulation and Distribution Characteristics among Three High-quality Late Rice Varieties

为比较3个优质晚稻品种(天优华占、星2号、湘晚籼13号)在重度镉污染稻田上的Cd积累分配特性差异,在土壤p H值6.65、人为添加2 mg/kg Cd的条件下开展了盆栽模拟试验。结果表明:水稻各器官Cd含量以根系和茎秆较高,叶片和稻穗较低;穗各部位Cd含量表现为枝梗>空粒>实粒。品种间Cd含量差异显著,整株Cd含量以星2号最高,另外两品种相当;穗、籽粒、糙米Cd含量表现为天优华占>星2号>湘晚籼13号的趋势。3个品种Cd积累总量的80.15%~89.33%来自齐穗之前;孕穗-收获,叶、茎Cd积累量持续增大,而根Cd积累量于灌浆中期达最大,穗Cd积累量于成熟期达最大;整株Cd积累量以星2号最高,天优华占最低;穗Cd积累量以天优华占最高,湘晚籼13号最低。Cd在水稻植株各器官的分配比例存在品种间差异,湘晚籼13号茎秆占全株Cd积累量的比例最高,籽粒所占比例最低,而天优华占则刚好相反。单穴产量以湘晚籼13号最高,天优华占最低,两者差异显著。本试验条件下,天优华占糙米Cd含量略超国家标准(0.2 mg/kg),星2号与湘晚籼13号糙米Cd含量在国家标准以内。可见,在重度镉污染稻田上,星2号与湘晚籼13号能够实现稻米安全生产,综合来看以湘晚籼13号表现较优。

In order to compare the characteristics of Cd accumulation and distribution of three high-quality late rice varieties,Tianyouhuazhan,Xing No.2 and Xiangwanxian No.13,in paddy field with heavy Cd contamination,a pot culture experiment was conducted under conditions of soil pH 6.65 and 2 mg/kg Cd added by men in soil.The results showed that:In organs of rice plant,Cd content of roots and stems was higher,and that in leaves and panicles was lower.Cd content parts of panicle showed the trend of branch>empty grain>filled grain.There existed significant difference in Cd content among varieties.Cd content in whole plant of Xing No.2 was highest,that of other two varieties was equal.Cd content in panicle,grain and brown rice showed the trend of Tianyouhuazhan>Xing No.2>Xiangwanxian No.13.80.15%-89.33%of total Cd was accumulated before heading stage.From booting to harvest,Cd accumulation in leaves and stems was continuously increased,that in roots was reached top point at mid-filling stage,and Cd accumulation in panicle reached maximum at maturity.As for Cd accumulation of whole plant,Xing No.2 was highest,and Tianyouhuazhan was lowest.As for Cd accumulation in panicle,Tianyouhuazhan was highest,and Xiangwanxian No.13 was lowest.There existed varietal difference in distribution ratio of Cd in organs of rice plant.As for Xiangwanxian No.13,ratio of Cd accumulation in stems to whole plant was highest,and ratio of Cd accumulation in grains to whole plant was lowest,while Tianyouhuazhan showed the contrary trend.Yield per hill of Xiangwanxian No.13 was highest,that of Tianyouhuazhan was lowest,and the difference was significant.Under conditions in this study,Cd content in brown rice of Tianyouhuazhan was slightly higher than national standard(0.2 mg/kg),and that of Xing No.2 and Xiangwanxian No.13 was lower than national standard.These results showed that Xing No.2 and Xiangwanxian No.13 could realize rice safety production in paddy field with heavy Cd contamination.Comprehensively,Xiangwanxian No.13 was the better.