State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing, China; College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, P.O. Box 821, Nanjing, China.
Ecotoxicol Environ Saf. 2021 Jan 1;207:111224. doi: 10.1016/j.ecoenv.2020.111224. Epub 2020 Sep 2.
The roots of 4 japonica, 4 indica, and 7 hybrid rice varieties were obtained by hydroponic experiment and used to explore the relationship between charge characteristics and exchangeable manganese(II) (Mn(II)) on rice roots and Mn(II) absorption in roots and shoots of the rice. Results indicated Mn(II) adsorbed on rice roots mainly existed as exchangeable Mn(II) after 2 h. The roots of indica and hybrid rice carried more negative charges than the roots of japonica rice. Accordingly, this led to more exchangeable Mn(II) to be adsorbed on roots of indica and hybrid rice after 2 h and more Mn(II) absorbed in the roots of the same varieties after 48 h. However, this was contrary to the result of Mn(II) absorption in rice shoots after 48 h. Coexisting cations of K, Na, Ca, and Mg reduced the exchangeable Mn(II) on rice roots through their competition with Mn(II) for sorption sites on rice roots, which led to the decrease in Mn(II) absorption in rice roots and shoots. Ca and Mg showed a greater decrease in the Mn(II) absorbed in roots and shoots than K and Na. The reduction of Mn(II) absorption in the roots of indica rice and hybrid rice induced by Ca and Mg was more than that of japonica rice. This was attributed to more negative charges on the roots of the former than the latter. Therefore, the absorption of Mn(II) by rice roots was determined by surface charge properties and exchangeable Mn(II) on the rice roots. The results suggested that Ca and Mg have potential to alleviate Mn(II) toxicity to rice.
通过水培实验获得了 4 个粳稻、4 个籼稻和 7 个杂交稻品种的根系，用于探讨水稻根系电荷特性与可交换性二价锰（Mn(II)）和 Mn(II)在水稻根系和地上部吸收之间的关系。结果表明，水稻根系吸附的 Mn(II)在 2 h 后主要以可交换性 Mn(II)的形式存在。籼稻和杂交稻的根比粳稻的根带更多的负电荷。因此，这导致在 2 h 后，籼稻和杂交稻的根上吸附了更多的可交换性 Mn(II)，在 48 h 后同一品种的根中吸收了更多的 Mn(II)。然而，这与 48 h 后水稻地上部吸收 Mn(II)的结果相反。共存的 K、Na、Ca 和 Mg 阳离子通过与 Mn(II)竞争水稻根系上的吸附位点，减少了水稻根系上的可交换性 Mn(II)，从而导致 Mn(II)在水稻根系和地上部的吸收减少。Ca 和 Mg 比 K 和 Na 导致根和地上部吸收的 Mn(II)减少得更多。Ca 和 Mg 诱导的籼稻和杂交稻根系对 Mn(II)吸收的减少大于粳稻，这归因于前者的根比后者带更多的负电荷。因此，水稻根系对 Mn(II)的吸收取决于根系表面电荷特性和可交换性 Mn(II)。结果表明，Ca 和 Mg 具有缓解 Mn(II)对水稻毒性的潜力。
