Effect of biosolid application and bacterial inoculation on the chlorophyll content of Canavalia ensiformis during copper phytoremediation in soil

Abstract

Copper (Cu) mining pollution is an environmental challenge in many countries, as it compromises the quality of soil, water, and air, and affects living organisms. The chlorophyll content of plants growing in contaminated soils is a sensitive indicator of their nutritional status, photosynthetic capacity, and the stress induced by heavy metals. This study aimed to evaluate the effect of biosolid application and inoculation with Azospirillum brasilense and Bacillus aryabhattai on the chlorophyll content of Canavalia ensiformis grown in Cu-contaminated soil. The experiment was conducted in a greenhouse using a 3×2 factorial design, with three biosolid doses (equivalent to 0, 45, and 90 kg N ha⁻¹), with and without bacterial inoculation. Shoot and root dry mass and chlorophyll content were determined using a chlorophyll meter. The results indicated that biosolid application and bacterial inoculation did not significantly increase plant biomass, although there was a trend toward increased root biomass with bacterial inoculation. Increasing biosolid doses linearly enhanced leaf chlorophyll content. However, bacterial inoculation did not significantly influence this parameter. Biosolid application is a promising strategy to improve the physiological performance of C. ensiformis during the phytoremediation of Cu-contaminated soils.