The impact of heavy metal tolerant bacterium and Sargassum ilicifolium as organic fertilizer on growth and antioxidant enzymes of sunflower under lead (Pb) and nickel (Ni) stress

Abstract

Abstract Heavy metal pollutants i.e. lead and nickel are introduced to cultivable land through many sources and get accumulated in the soil profiles and contaminate water bodies which affect the growth and production of several crops. Seaweeds are rich in nutrients and have the ability to improve soil fertility by adding nutrients and organic contents to soil. In this study, S. ilicifolium was used with and without plant growth promoting rhizobacteria (PGPR) P. aeruginosa which showed heavy metal biodegradation capacity of 99.06% for lead and 98.8% for nickel against said metal stress. The individual and combined treatment of Sargassum ilicifolium as soil amendment and P. aeruginosa improved sunflower growth under 0.5 mM lead (Pb) and nickel (Ni) contaminations. The morphological characteristics of plants including shoot and root length and fresh weight were improved under stress and non-stressed condition. The biochemical analysis of proline, total phenols, peroxidase (POD), superoxide dismutase (SOD) and DPPH-radical scavenging activity also indicated that plant tolerance was improved under heavy metal stress.