Effect of phosphogypsum on growth, physiology, and the antioxidative defense system in sunflower seedlings

Abstract

Phosphogypsum (PG) is the solid waste product of phosphate fertilizer production and is characterized by high concentrations of salts, heavy metals, and certain natural radionuclides. The work reported in this paper examined the influence of PG amendment on soil physicochemical proprieties, along with its potential impact on several physiological traits of sunflower seedlings grown under controlled conditions. Sunflower seedlings were grown on agricultural soil substrates amended with PG at rates of 0, 2.5, and 5 %. The pH of the soil decreased but electrical conductivity and organic matter, calcium, phosphorus, sodium, and heavy metal contents increased in proportion to PG concentration. In contrast, no variations were observed in magnesium content and small increases were recorded in potassium content. The effects of PG on sunflower growth, leaf chlorophyll content, nutritional status, osmotic regulator content, heavy metal accumulation, and antioxidative enzymes were investigated. Concentrations of trace elements in sunflower seedlings grown in PG-amended soil were considerably lower than ranges considered phytotoxic for vascular plants. The 5 % PG dose inhibited shoot extension and accumulation of biomass and caused a decline in total protein content. However, chlorophyll, lipid peroxidation, proline and sugar contents, and activities of antioxidant enzymes such as superoxide dismutase and catalase increased. Collectively, these results strongly support the hypothesis that enzymatic antioxidation capacity is an important mechanism in tolerance of PG salinity in sunflower seedlings.

Exogenous ascorbic acid improves defence responses of sunflower (Helianthus annuus) exposed to multiple stresses

“…GST together with xenobiotic substances catalyzes the conjugation of GSH and plays an important role in detoxification [31]. Studies already exist showing that GST and GR activities change at sunflower exposed to different stresses [13,14,23,44]. In the present study, GST and GR enzyme activities were shown to be increased all stress groups, compared to control.…”

“…GR plays a major role in cell defense against oxidative stress. It efficiently maintains the reduced pool of GSH [14]. GST together with xenobiotic substances catalyzes the conjugation of GSH and plays an important role in detoxification [31].…”

Comparative photochemistry activity and antioxidant responses in male and female Populus cathayana cuttings inoculated with arbuscular mycorrhizal fungi under salt

“…cathayana cutting roots was suppressed by salt stress, which was mainly due to the direct effect of salt stress on fungi. Salt stress could hamper the colonization capacity by inhibiting spore germination27, hyphal growth in soil25 and hyphal spread after initial colonization9.…”

“…All these impacts contribute to stunted growth and production losses. Plants have various strategies to adapt to or avoid the damages caused by the activation of reactive oxygen species (ROS) and the accumulation of osmotic regulators89. That ROS generation and its scavenging system have a key effect in the defense of plants against various stresses has been well-documented1011.…”

Effects of sewage sludge on bio-accumulation of heavy metals in tomato seedlings

“…The direct and indirect discharges of industrial and urban wastes have resulted in the chemical contamination of the soil by organic pollutants and HMs (Sun et al, 2012;Elloumi et al, 2015). The presence of HMs in sewage sludge (SS), used as agricultural fertilizer is a major problem for soil and crop qualities.…”