Meharg Andrew A, Macnair Mark R
Department of Biological Sciences, Hatherly Laboratories, Prince of Wales Road, Exeter EX4 4PS, UK.
New Phytol. 1991 Oct;119(2):291-297. doi: 10.1111/j.1469-8137.1991.tb01033.x.
Arsenate influx isotherms in Deschampsia cespitosa (L.) Beauv. and Agrostis capillaris L. showed that tolerance to arsenate in these grasses is achieved at least in part by adaptation of the arsenate uptake system, which leads to reduced influx of arsenate in arsenate-tolerant plants. In D. cespitosa, this reduction in arsenate ioflux was by suppression of the V of the high-affinity uptake system and by an increase in the K of the low-affinity uptake system. In A. capillaris the reduction in arsenate uptake in arsenate-tolerant plants was by a decrease in the V of both uptake systems and by an increase in the K of the high-affinity uptake system. The differences in the rates of arsenate influx between tolerant and non-tolerant plants was much greater for D. cespitosa than for A. capillaris. The mechanism of arsenate tolerance in D. cespitosa and A. capillaris was the same mechanism of tolerance that had been demonstrated in arsenate-tolerant Holcus lanatus L. Reduced arsenate influx by adaptation of the arsenate uptake mechanism is a mechanism of tolerance that has evolved in three separate species.
苔草（Deschampsia cespitosa (L.) Beauv.）和细弱剪股颖（Agrostis capillaris L.）中砷酸盐流入等温线表明，这些禾本科植物对砷酸盐的耐受性至少部分是通过砷酸盐吸收系统的适应性实现的，这导致耐砷酸盐植物中砷酸盐的流入减少。在苔草中，砷酸盐流入量的减少是通过抑制高亲和力吸收系统的V值以及增加低亲和力吸收系统的K值来实现的。在细弱剪股颖中，耐砷酸盐植物中砷酸盐吸收的减少是通过两个吸收系统的V值降低以及高亲和力吸收系统的K值增加来实现的。耐砷和非耐砷植物之间砷酸盐流入速率的差异在苔草中比在细弱剪股颖中要大得多。苔草和细弱剪股颖中砷酸盐耐受机制与耐砷酸盐的绒毛草（Holcus lanatus L.）中所证明的耐受机制相同。通过砷酸盐吸收机制的适应性来减少砷酸盐流入是在三个不同物种中进化出的一种耐受机制。
