高、低Cd积累水稻和小麦籽粒中Cu、Zn的富集特性

Accumulation of Copper and Zinc in Grains of Rice and Wheat Cultivars With Contrasting Cadmium Uptake Capacities

Cu、Zn含量过低不仅直接关系到稻麦植物的生长发育和籽粒的营养品质,而且与人类的饮食健康密切相关。采集我国水稻优势产区典型土壤,选择Cd高、低积累性明显不同的水稻和小麦品种各2个,通过温室盆栽试验研究稻-麦轮作体系下植物可食部分Cu、Zn吸收性差异。结果表明,高、低Cd积累水稻糙米Cu平均含量分别为5.07和5.75 mg·kg^(-1),Zn平均含量分别为42.10和33.60 mg·kg^(-1),品种间差异显著(P<0.05);高、低Cd积累小麦籽粒Cu平均含量分别为4.37和4.94 mg·kg^(-1),Zn平均含量分别为34.40和35.40 mg·kg^(-1),差异不显著。高、低Cd积累小麦籽粒Cu、Zn含量差异不显著,可能与小麦籽粒Cu、Zn变异系数大多属于强变异有关。稻麦籽粒对Zn的富集系数均高于Cu;对于东北地区土壤,高和低Cd积累水稻糙米Cu、Zn富集系数分别为0.31、0.73和0.41、0.64,而高和低Cd积累小麦Cu、Zn富集系数分别为0.19、0.44和0.22、0.42,即糙米Cu、Zn富集能力显著高于小麦。因此,与小麦相比,在北方种植水稻能更有效地提高Cu、Zn在作物中的富集。上述结果表明,从稻麦的安全品质和营养品质方面考虑,种植高、低Cd积累稻麦不会导致Cu、Zn含量过低而引起营养失衡。

Low contents of copper(Cu)and zinc(Zn)in rice and wheat grains will affect not only plant growth and grain nutritional value but also the suitability of the grains in human diet.A pot experiment was conducted using selected typical paddy soils in the dominant rice producing areas of China to study the differences in Cu and Zn uptake in rice-wheat rotation systems with two cultivars of rice and of wheat with contrasting cadmium(Cd)accumulation capacities.There were significant differences in the average concentrations of Cu and Zn in high and low Cd accumulating rice cultivars,with Cu concentrations of 5.07 and 5.75 mg·kg^-1 and Zn concentrations of 42.10 and 33.60 mg·kg^-1,respectively.However,there were no significant differences in the average Cu and Zn concentrations in the high and low Cd accumulation wheat cultivars,with 4.37 and 4.94 mg·kg^-1 Cu and 34.40 and 35.40 mg·kg^-1 Zn,respectively.Summarizing the previous results,the differences in high and low Cd accumulation in wheat were not significantly related to the large differences in Cu and Zn in the wheat grains.The Zn bio-concentration factors(BCF)of rice and wheat were higher than those of Cu.The Cu and Zn BCF of high and low Cd accumulation rice cultivars grown in soils from northeast China were 0.31 and 0.73,and 0.41 and 0.64,respectively.However,the Cu and Zn BCF of the high and low Cd accumulation wheat cultivars were only 0.19 and 0.44,and 0.22 and 0.42,respectively.Growing rice in the northern region can therefore increase the enrichment of Cu and Zn in rice more effectively than in wheat.These results indicate that,in terms of the safety and nutritional quality of rice and wheat,planting high and low Cd accumulating rice and wheat will not result in Cu and Zn nutrient imbalance.