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The effects of phosphate on arsenic uptake and toxicity alleviation in tobacco genotypes with differing arsenic tolerances

Zvobgo, Gerald, Hu, Hongliang, Shang, Shenghua, Shamsi, Imran Haider, Zhang, Guoping
Environmental toxicology and chemistry 2015 v.34 no.1 pp. 45-52
Nicotiana tabacum, arsenic, catalase, genotype, hydroponics, leaves, malondialdehyde, nutrient content, nutrient uptake, photosynthesis, superoxide dismutase, tobacco, toxicity
Phosphate (PO₄³–) has been reported to suppress arsenate (Asᵛ) uptake in plants. However, its effects on controlling the availability of Asᵛin tobacco genotypes with different arsenic (As) tolerances has not been fully explored. In the present study, the effects of PO₄³–on Asᵛuptake were investigated in a hydroponic culture using 2 tobacco (Nicotiana tabacum) genotypes (ZY90 and FSMY) that differed in Asᵛtolerance. A total of 9 treatment combinations comprising Asᵛtreatments of 0 µM, 10 µM, and 100 µM and PO₄³–treatments of 0 µM, 50 µM, and 500 µM were used. The results showed that ZY90 had greater reductions in leaf photosynthetic parameters, root and shoot dry weight, length, and nutrient content than did FSMY when exposed to Asᵛstress. The addition of 500 µM external PO₄³–significantly suppressed Asᵛ(100 µM) uptake in both FSMY and ZY90, with the effect being more pronounced in FSMY. Greater PO₄³–uptake in plants significantly reduced the influx of Asᵛ, causing an increase in photosynthesis and nutrient uptake. Phosphate supply increased superoxide dismutase activity, catalase activity, and malondialdehyde content. The present study showed that PO₄³–is an effective competitive inhibitor of Asᵛ, and it can be effectively used to control Asᵛaccumulation in tobacco plants. Environ Toxicol Chem 2015;34:45–52. © 2014 SETAC