School of Life Science, Northwest Normal University, Lanzhou 730070, People's Republic of China.
Ecotoxicol Environ Saf. 2010 Nov;73(8):1982-7. doi: 10.1016/j.ecoenv.2010.08.041. Epub 2010 Sep 15.
The mechanism of lead-inhibitory effects on seed germination and seedling growth was investigated in wheat cv. Xihan 2 subjected to different Pb(NO(3))(2) concentrations. High concentrations of lead and exogenous H(2)O(2) significantly inhibited seed germination and the growth of roots and shoots. Dimethylthiourea, catalase or diphenylene iodonium could reverse lead-inhibitory effects on seed germination. Significant elevated H(2)O(2) generation was observed in germinating seeds exposed to lead. Analysis using fluorescent dye 2',7'-dichlorodihydrofluorescein diacetate showed significantly increased H(2)O(2) level in the root tissue in response to lead treatment. Nitric oxide (NO) donor sodium nitroprusside could alleviate the Pb-inhibitory effects on seed germination and shoot growth, which was blocked by guanylyl cyclase inhibitor methylene blue. Therefore, NADH-dependent generation of extracellular H(2)O(2) is responsible for Pb-inhibitory effect on seed germination, the protection of exogenous NO against lead toxicity involved in seed germination and seedlings shoot growth may be associated with cGMP signaling pathway.
研究了不同浓度硝酸铅（Pb(NO(3))(2)）处理下西旱 2 号小麦种子萌发和幼苗生长受抑制的作用机制。高浓度的铅和外源 H(2)O(2)显著抑制种子萌发和根、茎的生长。二甲基硫脲、过氧化氢酶或二苯基碘鎓可以逆转铅对种子萌发的抑制作用。在暴露于铅的萌发种子中观察到 H(2)O(2)生成显著增加。使用荧光染料 2'，7'-二氯二氢荧光素二乙酸酯进行分析表明，根组织中 H(2)O(2)水平响应铅处理而显著增加。一氧化氮（NO）供体硝普钠可以缓解铅对种子萌发和幼苗茎生长的抑制作用，而鸟苷酸环化酶抑制剂亚甲蓝则阻断了这一作用。因此，NADH 依赖性细胞外 H(2)O(2)的生成是导致铅对种子萌发抑制的原因，外源 NO 对铅毒性的保护作用可能与 cGMP 信号通路有关。
