水稻土中7个水稻品种对土壤Cd、Pb的富集与转运:田间研究

A Field Study on the Accumulation and Translocation of Cadmium and Lead from A Contaminated Paddy Rice Field by Seven Rice Cultivars

近年来,稻米Cd、Pb含量超标问题频繁出现,稻米质量安全备受关注。通过在Cd-Pb复合污染土壤上,采用田间试验方法研究了7个水稻(Oryza.sativa L.)品种(宜优673、东联5号、花优63、春优84、浙优18、甬优9号和台粳8号)对土壤Cd和Pb的富集与转运能力,并探讨了影响稻米富集Cd和Pb的因素,以期为Cd、Pb污染农业土壤的安全利用提供依据。研究结果表明,Cd、Pb主要富集在水稻根中,Cd、Pb在各组织中的含量分别表现为根>茎>叶>糙米、根>叶>茎>糙米。糙米Cd、Pb含量分别为0.06~0.18、0.09~0.31 mg·kg^(-1),品种间Cd、Pb含量差异均达显著水平(P<0.05);供试水稻糙米中Cd含量均未超标(0.2 mg·kg^(-1),GB2762—2017),除台粳8号以外,其他品种糙米Pb含量也未超标(0.2 mg·kg^(-1),GB2762—2017)。糙米Cd含量随稻谷产量的升高而升高,糙米Pb含量则随稻谷产量的升高而降低。不同水稻品种对土壤Cd的富集能力表现为:春优84>甬优9号>浙优18>宜优673>东联5号、花优63、台粳8号,最大相差2.4倍;对土壤Pb的富集能力表现为:台粳8号>宜优673>浙优18>花优63、春优84、甬优9号>东联5号,最大相差3.3倍。高根表铁膜Cd含量促进了水稻根系对Cd的吸收,但高根表铁膜Pb含量则抑制了根系对Pb的吸收。糙米Cd含量随Cd在茎-糙米和叶-糙米之间的转移系数的升高而升高(P<0.01),但糙米Pb含量与Pb在茎-糙米和叶-糙米之间的转移系数无明显相关(P<0.01)。台梗8号是低产低Cd累积品种,东联5号为高产低Cd积累品种,东联5号和甬优9号为高产低Pb积累品种,在Cd污染、Pb污染或Cd-Pb复合污染的农田上可以酌情选种。

In recent years, cadmium and lead contaminated rice, becomes a well-recognized threat to human health and food quality. A field experiment was carried out on Cd/Pb polluted paddy rice field, in order to study the accumulating ability and translocation of Cd and Pb from the soil by 7 rice （Oryza.sativa L.） cultivars （Yiyou 673, Donglian 5, Huayou 63, Chunyou 84, Zheyou 18, Yongyou 9 and Taigeng 8）, factors affecting the accumulation of Cd and Pb in rice grains were also studied. The results showed that Cd and Pb were mainly concentrated in rice roots, whereas, the contents of Cd and Pb in brown rice were 0.06~0.18 mg·kg-1 and 0.09~0.31 mg·kg-1, respectively. There was a significant difference between the Cd and Pb contents in brown rice （P〈0.05） of different rice cultivars. The Cd content in brown rice of the cultivars was below the limit for rice （0.2 mg·kg-1, GB2762—2017）, except for Taigeng 8, the Pb contents in other cultivars were lower than the limit for rice （0.2 mg·kg-1, GB2762—2017）. The Cd content in brown rice increased, whereas, the Pb content in brown rice decreased with increasing rice yield. The transfer factor of Cd from soil-to-brown rice decreased in the order of Chunyou 84〉Yongyou 9〉Zheyou 18〉Yiyou 673〉Donglian 5, Huayou 63, Taigeng 8 with the largest difference of 2.4. Also, the transfer factor of Pb from soil-brown rice decreased in the order of Taigeng 8〉Yiyou 673〉Zheyou 18〉Huayou 63, Chunyou 84, Yongyou 9〉Donglian 5 with the largest difference of 3.3. A higher Cd content in Fe-plaques favors Cd uptake, whereas, a higher Pb content in Fe-plaques inhibited Pb uptake by rice roots. The Cd concentration in brown rice increased with increasing TFstem-grain and TFleaf-grain （P〈0.01）. There was no relationship between the Pb content in brown rice with TFstem-grain and TFleaf-grain （P〈0.01）. Our results showed that Taigeng 8 is a low-yield and low-Cd accumulating cultivar, while Donglian 5 is a high-yield and low-Cd accumulating cultivar, which can be cultivated on Cd-polluted fields. Donglian 5 and Yongyou 9 are high-yield and low-Pb accumulating cultivars, which can be cultivated on Pb-polluted fields. Nevertheless, on Cd/Pb combined polluted fields, the low-Cd and low-Pb accumulating cultivar Donglian 5 can be cultivated.