Effect of external and internal phosphate status on arsenic toxicity and accumulation in rice seedlings

Abstract

Phosphorus (P) deficiency is thought to exacerbate the arsenic (As) phytotoxicity in paddy rice. The experiments were conducted to investigate the effects of external phosphate supply on As accumulation in rice and its toxicity under phosphate deficiency conditions. Rice seedlings pretreated with a phosphorus deficient nutrient solution (-P) for 14 d accumulated more As than those pretreated with a normal phosphorus supply nutrient solution (+P). Rice protreated with -P showed As toxicity symptoms after being exposed to 50 μmol/L arsenate for 4 h, while +P rice did not show any toxicity symptoms. Arsenic toxicity symptoms can be alleviated by increasing external P concentrations. The arsenate uptake rate and accumulation corresponded with the As toxicity in rice plants. Arsenic concentrations in rice roots decreased with increasing external phosphate concentrations. The lowest As accumulation and the highest P accumulation were found when the external P concentration reached 100 μmol/L. In short, P deficiency increased the sensitivity of rice to arsenate and increasing of external phosphate supply could alleviate As toxicity.

Phosphate deficiency signaling pathway is a target of arsenate and phosphate transporterOsPT1is involved in As accumulation in shoots of rice

“…S1C). These results are in agreement with the results of Wang and Duan (2009) and showed that our experimental conditions worked well.…”

Effects of high concentrations of soil arsenic on the growth of winter wheat (Triticum aestivum L) and rape (Brassica napus)

“…Wang and Duan (2009) reported that P deficiency increased the sensitivity of rice to arsenate and increased external phosphate supply could alleviate As toxicity. It could be assumed that the effects of soil As on wheat and rape depended on the concentrations of both P and As in the two plants.…”

“…Some researches reported that As sensitivity was intimately linked to P nutrition in plants, and applying P fertilizers could increase As availability in soils and enhanc plant uptake of As (Geng et al 2006, Wang and Duan 2009. In the other way, different soil As concentrations can also affect soil P availability.…”

Effects of Phosphorus Fertilization on Arsenic Uptake by Wheat Grown in Polluted Soils

“…However, As sensitivity is intimately linked to P nutrition in plants. In rice seedlings, even cultivars found to be susceptible to arsenate can become more resistant by raising level of intracellular P (Geng et al, 2006;Wang and Duan, 2009). Gultz et al (2005) reported that P availability and P demand, which are plant specific, have to be taken in account to predict uptake of As by crop plants.…”