State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing, China.
University of Chinese Academy of Sciences, Beijing, 100049, China.
Environ Sci Pollut Res Int. 2024 May;31(21):30399-30414. doi: 10.1007/s11356-024-33228-7. Epub 2024 Apr 12.
The rapid increase in soil acidity coupled with the deleterious effects of cadmium (Cd) toxicity had led to a decline in worldwide agricultural production. Rice absorbs and accumulates Cd(II) from polluted paddy soils, increasing human health risks throughout the food chain. A 35-day hydroponic experiment with four japonica and four indica (two each of them tolerant and sensitive cultivars) was conducted in this study to investigate the adsorption and absorption of Cd(II) by rice roots as related with surface chemical properties of the roots. The results showed that the three chemical forms of exchangeable, complexed, and precipitated Cd(II) increased with the increase in Cd(II) concentration for all rice cultivars. The roots of indica rice cultivars carried more negative charges and had greater functional groups and thus adsorbed more exchangeable and complexed Cd(II) than those of japonica rice cultivars. This led to more absorption of Cd(II) by the roots and greater toxicity of Cd(II) to the roots of indica rice cultivars and more inhibition of Cd(II) stress on the growth of the roots and whole plants of indica rice cultivars compared with japonica rice cultivars, which was one of the main reasons for more declines in the biomass and length of indica rice roots and shoots than japonica rice cultivars. Cd(II) stress showed more toxicity to the sensitive rice cultivars and thus greater inhibition on the growth of the cultivars due to more exchangeable and complexed Cd(II) adsorbed by their roots induced by more negative charges and functional groups on the roots compared with tolerant rice cultivar for both indica and japonica, which resulted in greater decreases in the biomass and length of roots and shoots as well as chlorophyll contents of the sensitive cultivars than the tolerant cultivars. The roots of sensitive rice cultivars also absorbed more Cd(II) than tolerant rice cultivars due to the same reasons as above. These findings will provide useful references for the safe utilization and health risk prevention of Cd-contaminated paddy fields.
土壤酸度的迅速增加加上镉 (Cd) 毒性的有害影响，导致全球农业产量下降。水稻从受污染的稻田中吸收和积累 Cd(II)，增加了整个食物链中人类健康的风险。本研究进行了为期 35 天的水培实验，用四个粳稻和四个籼稻（每个各有两个耐受和敏感品种），以调查 Cd(II)在水稻根系中的吸附和吸收与根系表面化学性质的关系。结果表明，所有水稻品种的可交换态、络合态和沉淀态 Cd(II)三种化学形态均随 Cd(II)浓度的增加而增加。籼稻品种的根系带更多的负电荷，具有更多的功能基团，因此比粳稻品种吸附更多的可交换态和络合态 Cd(II)。这导致籼稻品种的根系吸收更多的 Cd(II)，Cd(II)对籼稻品种的根系毒性更大，Cd(II)对籼稻品种根系和整个植株生长的抑制作用更大，这是导致籼稻品种根系和地上部分的生物量和长度比粳稻品种下降更多的主要原因之一。Cd(II)胁迫对敏感水稻品种的毒性更大，因此由于其根系上更多的负电荷和功能基团吸附更多的可交换态和络合态 Cd(II)，导致其生长受到更大的抑制，这对于籼稻和粳稻的耐受品种都是如此，这导致敏感品种的根系和地上部分的生物量和长度以及叶绿素含量的下降大于耐受品种。由于上述相同的原因，敏感水稻品种的根系也吸收了比耐受品种更多的 Cd(II)。这些发现将为受 Cd 污染的稻田的安全利用和健康风险预防提供有用的参考。
