SUPPRESSION OF THE HIGH-AFFINITY PHOSPHATE-UPTAKE SYSTEM - A MECHANISM OF ARSENATE TOLERANCE IN HOLCUS-LANATUS L
SUPPRESSION OF THE HIGH-AFFINITY PHOSPHATE-UPTAKE SYSTEM - A MECHANISM OF ARSENATE TOLERANCE IN HOLCUS-LANATUS L
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DOI：
10.1093/jxb/43.4.519
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发表时间：
1992-04-01
影响因子：
6.9
通讯作者：
MACNAIR, MR
中科院分区：
文献类型：
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作者：
MEHARG, AA;MACNAIR, MR
毛茛Holcus lanatus L.磷酸盐和砷酸盐由同一运输系统吸收。短期吸收动力学的高亲和力砷酸盐运输系统测定离体根的砷酸盐耐受和非耐受基因型。在耐受植物中，在无磷培养基中生长的植物中的离子吸收的V（max）与非耐受植物相比降低，并且吸收系统的亲和力低于非耐受植物。V（max）的降低和K（m）的增加都导致了进入耐受根的砷酸盐流入减少。当这两种基因型生长在营养液中含有高水平的磷酸盐，有耐受植物的吸收动力学变化不大。在非耐性植物中，V（max）显著降低到耐性植物的水平，而K（m）变化不大。这表明，在广泛的范围内不同的根磷酸盐状态的砷酸盐吸收率低是由于损失的诱导合成的砷酸盐（磷酸盐）载体。
In Holcus lanatus L. phosphate and arsenate are taken up by the same transport system. Short-term uptake kinetics of the high affinity arsenate transport system were determined in excised roots of arsenate-tolerant and non-tolerant genotypes. In tolerant plants the V(max) of ion uptake in plants grown in phosphate-free media was decreased compared to non-tolerant plants, and the affinity of the uptake system was lower than in the non-tolerant plants. Both the reduction in V(max) and the increase in K(m) led to reduced arsenate influx into tolerant roots. When the two genotypes were grown in nutrient solution containing high levels of phosphate, there was little change in the uptake kinetics in tolerant plants. In non-tolerant plants, however, there was a marked decrease in the V(max) to the level of the tolerant plants but with little change in the K(m). This suggests that the low rate of arsenate uptake over a wide range of differing root phosphate status is due to loss of induction of the synthesis of the arsenate (phosphate) carrier.