Influence of synthetic chelators and LMWOAs on the yield and quality attributes of Panicum maximum Jacq. (Poales: Poaceae) in chromium phytoextraction

Abstract

Phytoextraction is a cost-effective technology for contaminated site remediation. The study was carried out to investigate the potential of Panicum maximum (Jacq.) to remediate Cr-contaminated soil in tannery industries. Using chromium chelators and hyperaccumulating plants (Guinea grass), efforts have been made to decontaminate the chromium-contaminated tannery sites. To evaluate, the pot experiment was conducted, and Guinea grass’s yield and quality parameters were analyzed. The changes in root length, shoot length, and number of tillers were studied for three months, and the maximum values were 12.6 cm, 163.6 cm, and 12.6 cm, respectively, in the treatment with citric acid. The fodder quality parameters such as crude protein (9.2%), crude fibre (27.24%), and green leaf yield (370.3 g/plant) were magnificent in the treatment with citric acid as the chelator. Indeed, maximum hexavalent chromium (2.94 ± 0.06) and total chromium (17.98 ± 0.05) were observed in the citric acid treatment. Among all the treatments analyzed, the low-molecular-weight organic acids (LMWOAs), especially citric acid at 5 mmol/kg, were the best ones that could be recommended for improving the chelating process in the phytoremediation of chromium by Guinea grass. However, among the synthetic chelators, EDTA has resulted in higher chromium chelation and yield attributes such as root length (10.7 cm), shoot length (153.6 cm), number of tillers (10.3), and quality parameters like Guinea grass such as crude protein (8.1%), crude fibre (28.03%), and green leaf yield (342.6 g/plant). The study indicates that the chelators are enhancing Guinea grass growth and incorporating that may assist in the phytoremediation process.