Zhao F J, Wang J R, Barker J H A, Schat H, Bleeker P M, McGrath S P
Agriculture and Environment Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
Crop Performance and Improvement Division, Long Ashton Research Station, Long Ashton, Bristol, BS41 9AF, UK; and.
New Phytol. 2003 Aug;159(2):403-410. doi: 10.1046/j.1469-8137.2003.00784.x.
• Pteris vittata was the first identified arsenic (As) hyperaccumulator. Here we investigated whether phytochelatins (PCs) are involved in the hypertolerance of arsenic by P. vittata. • P. vittata was exposed to 0-500 µm arsenate for 5 d, or to 50 µm arsenate for 0-7 d. In addition, l-buthionine-sulphoximine (BSO), an inhibitor of γ-glutamylcysteine synthetase, was used in combination with different arsenate exposures. The relationships between As accumulation and the concentrations of PCs and glutathione (GSH) were examined. • PC synthesis was induced upon exposure to arsenate in P. vittata, with only PC detected in the plant. The As concentration correlated significantly with PC concentration in both roots and shoots, but not with GSH. The molar ratio of PC-SH to As was c. 0.09 and 0.03 for shoots and roots, respectively, suggesting that only a small proportion (1-3%) of the As in P. vittata can be complexed with PCs. In the presence of arsenate, addition of BSO decreased PC concentrations in roots and shoots by 89-96% and 30-33%, respectively. BSO alone was found to inhibit root growth of P. vittata markedly. • The results suggest that PCs play a limited role in the hypertolerance of As in P. vittata.
• 蜈蚣草是首个被鉴定出的砷超富集植物。在此，我们研究了植物螯合素（PCs）是否参与蜈蚣草对砷的超耐受性。
• 蜈蚣草暴露于0 - 500 μmol/L的砷酸盐中5天，或暴露于50 μmol/L的砷酸盐中0 - 7天。此外，γ-谷氨酰半胱氨酸合成酶抑制剂L-丁硫氨酸亚砜胺（BSO）与不同的砷酸盐暴露联合使用。研究了砷积累与PCs和谷胱甘肽（GSH）浓度之间的关系。
• 蜈蚣草暴露于砷酸盐后诱导了PCs的合成，植物中仅检测到PCs。根和地上部的砷浓度与PCs浓度显著相关，但与GSH无关。地上部和根中PC-SH与砷的摩尔比分别约为0.09和0.03，这表明蜈蚣草中只有一小部分（1 - 3%）的砷能与PCs络合。在有砷酸盐存在的情况下，添加BSO分别使根和地上部的PCs浓度降低了89 - 96%和30 - 33%。单独使用BSO被发现能显著抑制蜈蚣草的根生长。
• 结果表明，PCs在蜈蚣草对砷的超耐受性中起有限作用。
