Investigation of the effect of phosphogypsum amendment on two Arabidopsis thaliana ecotype growth and development.

The production of phosphoric acid from natural phosphate rock leads to an industrial waste called phosphogypsum (PG). About 5 tons of PG are generated per ton of phosphoric acid produced. This acidic waste (pH 2.2) is mostly disposed of by dumping into large stockpiles close to fertilizer production units, where they occupy large land areas that can cause serious environmental damages. Several attempts were made to test PG valorization via soil amendment because of its phosphate, sulphate and calcium content. The aim of the this study was to evaluate the potential use of PG as phosphate amendment in soil using two wild-type Arabidopsis thaliana ecotypes (Wassilewskija and Colombia) as model plants. Plants were grown in a greenhouse for 30 days, on substrates containing various PG concentrations (0%, 15%, 25%, 40% and 50%). The growth rate and physiological parameters (fresh weight, phosphate and chlorophyll content) were determined. The data revealed that 15% PG did not alter plant survival and leaf's dry weight, and the inorganic phosphate (Pi) uptake by plant seemed to be efficient. However, some alterations in Chlorophyll a/Chlorophyll b ratio were noticed. Higher PG concentrations (40 and 50% PG) exhibited an enhanced negative effect on plant growth, survival and Pi uptake. These inhibitory effects of the substrates may be related to the acidity of the medium in addition to its Cd content.