Phosphate and arsenate uptake by barley from soil is not explained by simple competition for a common transporter

摘要

We have investigated the barley growth response to arsenic in soil at two phosphate (P) levels and 5 arsenate (As) levels. In hydroponic studies P has been shown to have a 'protective' effect in regards to As toxicity, due to phosphate reducing the arsenate uptake. We found a 'protective' effect on growth that was significant at As levels lower than 15ppm. However, there was severe growth inhibition at all levels of As. In addition, our results show that there was no significant difference between As accumulation in shoot and root at high and low P levels below 20 ppm As. This was also the case for root and shoot As concentrations. So our results show that the P 'protective' effect is in fact not due to a reduced uptake of arsenate when P supply to barley grown in soil was increased.