Phosphate supply as a promoter of tolerance to arsenic in pearl millet

Document Type: Research Paper

Authors

1 Department of Bioscience & Biotechnology, Banasthali University, Rajasthan, 333031, INDIA.

2 Laboratory of Agronomy, Faculty of Crop Science, Agricultural University of Athens, 75, Iera Odos st., 11855 Athens, GREECE.

Abstract

Many soils are contaminated by heavy metals, with arsenic posing serious
environmental threat. Enrichment of soil with phosphate is believed to reduce the
arsenic toxicity. However, only a few attempts have already been conducted towards
understanding the precise role of phosphate in controlling As toxicity. Moreover,
there is no adequate information on the effect of phosphate on As-induced oxidative
stress, a major contributor of As toxicity in plant system. Τhe present study aims to
determine the effect of varying concentrations of phosphate on As-mediated
oxidative stress in pearl millet (Pennisetum typhoides). Our study revealed that a
concentration of 100 μM of phosphate was able to protect the test plant from As
(100μM)-mediated oxidative stress, as evident from the data on growth and lipid
peroxidation. This novel finding was further supported by the increased chlorophyll
content of the test plant raised in phosphate supplemented media. Phosphatemediated
improvement of antioxidant enzymes, such as SOD (superoxide
dismutase), CAT (catalase), and APX (peroxidase), could be a crucial factor in
regulating As-induced oxidative stress in pearl millet. The results of the present study
suggest that availability of phosphate in the surrounding media has a clearly pivotal
role in the generation of oxidative stress in P. typhoides exposed to As

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