Mechanisms of arsenate tolerance in Cytisus striatus
Mechanisms of arsenate tolerance in Cytisus striatus
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DOI：
10.1046/j.1469-8137.2003.00542.x
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发表时间：
2003-01-01
期刊：
影响因子：
9.4
通讯作者：
Ernst, WHO
中科院分区：
文献类型：
--
作者：
Bleeker, PM;Schat, H;Ernst, WHO
在不同的磷供应速率下，比较了富砷金矿和非金属矿区的金雀花种群对砷的耐受性、吸收和砷诱导的植物螯合蛋白(PC)的积累。砷的吸收是磷酸盐抑制的，在矿山植物中要低得多。在相同的胁迫水平下，矿生植物和非金属植物表现出相似的砷积累，这表明砷的吸收减少是耐性增强的主要原因。砷诱导的PC积累发生在两种植物类型中。γ-谷氨酰半胱氨酸合成酶抑制剂L-丁硫氨酸亚磺胺在两种植物类型中都引起了砷酸过敏，这表明基于PC的砷隔离对于正常和增强的砷耐性都是必不可少的。矿生植物比非金属植物产生更长的磷酸盐，这可能是由于砷积累的不同时间模式所致。我们的结果与条纹草和禾本科植物对砷的高度耐受的类似机制是一致的，即通过抑制磷酸盐转运体的活性来减少对砷的吸收。
Arsenate tolerance, uptake and arsenate-induced phytochelatin (PC) accumulation were compared at different phosphorus supply rates in two populations of the broom, Cytisus striatus, one from an arsenic-enriched gold mine and one from a nonmetalliferous site.After 7 d of exposure, arsenate tolerance was higher in the mine population. Arsenate uptake was phosphate-suppressible, and much lower in the mine plants. When compared at equal levels of stress, the mine plants and the nonmetallicolous plants exhibited similar arsenic accumulation, suggesting that reduced arsenate uptake is mainly responsible for superior tolerance.Arsenate-induced PC accumulation occurred in both plant types. The gamma-glutamylcysteine synthetase inhibitor, L-buthioninesulfoximine, caused arsenate hypersensitivity in both plant types, suggesting that PC-based arsenic sequestration is essential for both normal and enhanced arsenate tolerance. Mine plants produced longer PCs than the nonmetallicolous plants, possibly due to a differential temporal pattern of arsenate accumulation.Our results are consistent with a similar mechanism underlying arsenate hypertolerance in C. striatus and grasses, that is reduced arsenate uptake through suppression of phosphate transporter activity.