Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, PR China; College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China.
College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, PR China.
Ecotoxicol Environ Saf. 2018 Oct;161:534-541. doi: 10.1016/j.ecoenv.2018.06.015. Epub 2018 Jun 18.
Iron plaque (IP) on root surface can enhance the tolerance of plants to environmental stresses. However, it remains unclear the impact of Fe on cadmium (Cd) toxicity to rice (Oryza sativa) seedlings. In this study, the effects of different Fe and Cd concentration combinations on rice growth were examined hydroponically. Results indicated that Fe concentration up to 3.2 mM did not damage rice roots while induced IP formation obviously. Cd of 10 μM repressed rice growth significantly, while the addition of 0.2 mM Fe to 10 μM Cd solution (Cd+Fe) did not damage rice roots, indicating that Fe could ameliorate Cd toxicity to rice seedlings. Microstructure analysis showed Cd+Fe treatment induced the formation of IP with dense and intricate network structure, Cd adsorption on the root surface was reduced significantly. Cd concentration of rice roots and shoots and Cd translocation from roots to shoots with Fe+Cd treatment were reduced by 34.1%, 36.0% and 20.1%, respectively, in comparison to a single Cd treatment. Noteworthy, the removal of IP resulted in a larger loss of root biomass under Cd treatment. In addition, Cd+Fe treatment increased the activities of root superoxide dismutase and catalase by 105.5% and 177.4%, and decreased HO and O· accumulation of rice roots by 56.9% and 35.9%, and recovered Cd-triggered electrolyte leakage obviously, when compared with a single Cd treatment. The results from this experiment indicated that the formed dense IP on rice roots decreased Cd absorption and reactive oxygen species accumulation, and Fe supply alleviated Cd toxicity to rice seedlings.
铁斑块（IP）在根表面可以增强植物对环境胁迫的耐受能力。然而，铁对水稻幼苗镉毒性的影响仍不清楚。在这项研究中，通过水培实验研究了不同铁和镉浓度组合对水稻生长的影响。结果表明，铁浓度高达 3.2mM 不会损害水稻根系，同时明显诱导 IP 形成。10μM 的镉显著抑制水稻生长，而向 10μM 镉溶液中添加 0.2mM 铁（Cd+Fe）不会损害水稻根系，表明铁可以减轻镉对水稻幼苗的毒性。微观结构分析表明，Cd+Fe 处理诱导了致密而复杂的网络结构的 IP 形成，根表面的镉吸附量显著减少。与单一 Cd 处理相比，用 Fe+Cd 处理后，水稻根系和地上部分的 Cd 浓度以及 Cd 从根系向地上部分的转运分别降低了 34.1%、36.0%和 20.1%。值得注意的是，在 Cd 处理下，去除 IP 会导致根生物量更大的损失。此外，与单一 Cd 处理相比，Cd+Fe 处理使水稻根系超氧化物歧化酶和过氧化氢酶的活性分别增加了 105.5%和 177.4%，使 HO 和 O·在水稻根中的积累分别减少了 56.9%和 35.9%，并明显恢复了 Cd 引起的电解质渗漏。实验结果表明，水稻根系上形成的致密 IP 减少了 Cd 的吸收和活性氧的积累，铁的供应缓解了镉对水稻幼苗的毒性。
