不同品种水稻对砷的吸收转运及其健康风险研究

Arsenic Uptake and Translocation of Different Rice Cultivars and Its Health Risk

为了比较不同品种水稻砷的积累特点,筛选可食用部分低砷积累水稻品种,研究通过盆栽试验,分析了江苏省常见的11个水稻品种根、茎、叶、谷壳和籽粒中的砷含量、砷的转运系数和根表铁膜厚度及其对砷固持的影响,并预估了不同品种水稻籽粒砷的健康风险。结果表明,不同品种水稻各部位的砷含量差异显著(P <0.05),泰瑞丰5号籽粒中的砷含量最高,而镇稻16号籽粒中的砷含量最低,后者大约是前者的一半。砷在水稻相邻部位的转运系数存在品种间差异(P <0.05),砷在水稻叶与籽粒间的转运系数最大的水稻品种是泰瑞丰5号,最小的是镇稻16号。根表铁膜量在不同品种间差异显著(P <0.05),其中淮稻6号的铁膜量是武运粳23的2.17倍。根表铁膜量与铁膜中的砷含量及水稻根叶中的砷含量均呈显著正相关关系(P <0.05)。不同水稻品种间的目标风险指数(THQ)也存在显著差异,其中泰瑞丰5号的THQ值最高,而镇稻16号的THQ值最低,两者相差0.99倍。研究表明,镇稻16号由于较低的砷吸收和转运能力,在中低砷污染土壤上种植风险较小,而泰瑞丰5号风险最大。

In order to compare arsenic(As) accumulation characteristics among different rice cultivars and screen out rice cultivars with low As uptake capacity in edible parts, eleven rice cultivars widely grown in Jiangsu Province were employed in our pot experiment for analyzing As concentrations and As transfer factors in various rice tissues, iron plaque on root surface and As sequestration by iron plaque. Health risk of As in grain of different rice cultivars was also assessed. The results showed that As concentrations in various rice tissues among different rice cultivars were significantly different(P < 0.05), with the highest grain As concentration for Tairuifeng 5 and the lowest for Zhendao16, and the concentration in Zhendao 16 was about 50% of that in Tairuifeng 5. Transfer factors of As between adjacent tissues were significantly different among different rice cultivars, with the highest leaf-to-grain transfer factor for Tairuifeng 5 and the lowest for Zhendao 16. There was significant difference in iron plaque amount among different rice cultivars. Iron plaque amount of Huaidao 6 was 2.76 times as much as that of Wuyungeng 23. There was positive correlation between iron plaque and As sequestrated by iron plaque(r = 0.889, P < 0.001). Positive correlation between iron plaque and As concentrations in roots or leaf was also found. Target hazard quotient(THQ) was significantly different among different rice cultivars, with the highest for Tairuifeng 5 and the lowest for Huaidao 6. It is indicated that Zhendao 16 grown in soil with mild As pollution level has lower health risk because it has a lower uptake and transfer capacity of As, but Tairuifeng 5 has higher health risk.