Wang Lihong, Duan Guilan
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
J Environ Sci (China). 2009;21(3):346-51. doi: 10.1016/s1001-0742(08)62275-5.
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 micromol/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 micromol/L. In short, P deficiency increased the sensitivity of rice to arsenate and increasing of external phosphate supply could alleviate As toxicity.
磷（P）缺乏被认为会加剧水稻中砷（As）的植物毒性。开展了实验以研究在缺磷条件下，外部磷供应对水稻中砷积累及其毒性的影响。用缺磷营养液（-P）预处理14天的水稻幼苗比用正常供磷营养液（+P）预处理的幼苗积累了更多的砷。用-P预处理的水稻在暴露于50微摩尔/升砷酸盐4小时后出现了砷中毒症状，而+P处理的水稻未表现出任何中毒症状。通过提高外部磷浓度可缓解砷中毒症状。水稻植株中砷酸盐的吸收速率和积累与砷中毒情况相符。随着外部磷浓度的增加，水稻根中的砷浓度降低。当外部磷浓度达到100微摩尔/升时，砷积累量最低而磷积累量最高。简而言之，缺磷增加了水稻对砷酸盐的敏感性，增加外部磷供应可缓解砷毒性。
