Institute of Food Safety and Quality, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
Ecotoxicol Environ Saf. 2012 Feb;76(2):193-9. doi: 10.1016/j.ecoenv.2011.09.022. Epub 2011 Oct 28.
Irrigation with eutrophic water containing microcystins-LR (MC-LR) poses a potential risk to crops. However, the accumulation of MC-LR in rice grains and the mechanism of MC-LR-induced inhibition in rice roots are not understood. In this study, we detected the accumulation of MC-LR in rice grains collected from Taihu Lake region. MC-LR could accumulate in rice grains, but the risk evaluation suggested that MC-LR levels in rice grains from Taihu Lake region may not pose a threat to human health currently. In addition, MC-LR with low concentrations did not affect the growth of rice roots. However, MC-LR with high concentrations impeded the rice root morphogenesis by inhibiting root elongation, crown root formation, and lateral root development from primordia. Treatment with high concentrations of MC-LR stimulated the production of reactive oxygen species (ROS) and inhibited the production of nitric oxide (NO) in rice roots. Exogenous NO treatment reversed the inhibition of rice root growth under MC-LR stress. These results indicated that ROS and NO played important roles in the development of rice roots in responding to MC-LR stress.
富营养化水中的微囊藻毒素-LR（MC-LR）对作物可能构成潜在风险。然而，MC-LR 在水稻籽粒中的积累以及 MC-LR 诱导的水稻根系抑制的机制尚不清楚。在这项研究中，我们检测了来自太湖地区的水稻籽粒中 MC-LR 的积累。MC-LR 可以在水稻籽粒中积累，但风险评估表明，目前来自太湖地区的水稻籽粒中的 MC-LR 水平可能不会对人类健康构成威胁。此外，低浓度的 MC-LR 不会影响水稻根系的生长。然而，高浓度的 MC-LR 通过抑制根伸长、冠根形成和侧根从原基发育来阻碍水稻根形态发生。高浓度 MC-LR 处理刺激水稻根中活性氧（ROS）的产生，并抑制一氧化氮（NO）的产生。外源 NO 处理逆转了 MC-LR 胁迫下水稻根生长的抑制。这些结果表明，ROS 和 NO 在水稻根对 MC-LR 胁迫的响应中发挥了重要作用。
