Response of Nerium oleander to phosphogypsum amendment and its potential use for phytoremediation

•Soils amended with PG were impacted by high metal concentrations and salinity.•Nerium oleander may be used in the phytostabilization of metal polluted soils.•The biochemical response of N. oleander improves defense of plant against oxidative stress.

This work was carried out to check the feasibility of a sustainable disposal of phosphogypsum (PG) by application in agriculture. The objectives of this work were to examine the influence of PG amendment on soil physicochemical proprieties along with its potential impact on several biochemical and physiological traits of Nerium oleander grown under controlled conditions. N. oleander plants were grown on soil substrates amended with PG at rates of 0%, 5%, and 10%. The physicochemical proprieties of soil treated with PG amendment were investigated. The effects of PG on N. oleander growth, photosynthesis parameters, nutritional status, osmotic regulator contents, heavy metal accumulation and its potential to use in phytoremediation were also sought. Electrical conductivity, calcium, phosphorus, sodium, and heavy metal contents in soil amended increased in accordance with PG concentration. At 10% PG, soil pH decreased significantly in comparison with the control and soil amended with 5% PG, suggesting that acidity of the substrate influenced the availability of metal ions. Biomass accumulation, photosynthesis, leaf water potential, leaf chlorophyll and carotenoid contents were affected by 10% PG application in comparison with 5% PG and control. PG induced an increase in the rate of hydrogen peroxide production and lipid peroxidation in foliage, indicating oxidative stress. This redox stress affected photosynthesis, leaf water potential, leaf chlorophyll and carotenoid contents, which decreased in response to increased PG doses. However, soluble sugars and proline contents increased in all PG-treated plants compared with controls. N. oleander foliage contained increased concentrations of Zn, Fe, Ni and Cr. In contrast, low concentrations of Zn and Fe were found in the roots. The bioconcentration factor values of Zn, Ni and Cr in the root of N. oleander L. were greater than 1; which indicates the metals accumulation potential by this species. Translocation factor values of Ni and Cr were less than 1, which shows that Ni and Cr are stabilized in the root part of the plant. According to the metal accumulation patterns of N. oleander, this species seems to be valuable for application in the phytostabilization process of soil contaminated with Cr and Ni.