Comparative assessment of physiological and biochemical changes in the selected plant species growing under hydrocarbon stress

Abstract

Hydrocarbons have become a serious environmental problem due to industrialization and extensive use of vehicles. Various plant species shows a range of stress responses and adaptations to survive in hydrocarbon stress. This study was conducted to investigate the comparative phytotoxicity of PAHs on plants growing under hydrocarbons stress on the germination and to evaluate the response of seedling growth. For the study two crop plant species (Brassica juncea L. Czern., and Triticum aestivum L.) and two ornamental plants species (Tagetes erecta L. and Helianthus annuus L.) were taken. Pot experiments were conducted in triplicates of 10 days old seedlings were treated with 5, 20, 50 &100 mgkg-1 concentrations of hydrocarbons. After 20 days, biochemical analysis and antioxidant enzyme activity of these plants were studied. Polyphenol and proline increased with increasing concentration of hydrocarbons which were maximum in H. annuus with 0.909 mgg-1 polyphenol and 0.732 µmolg-1 proline at 100 mgkg-1. Increase in antioxidant enzymatic activities was observed with increasing concentration. H. annuus showed maximum activity at 100ppm which was APX (20.37 Unit g-1 FW), POD (0.212 Unit g-1 FW) and SOD (2.13 Unit g-1 FW). HPLC analysis in plants and soil provided the concentration of hydrocarbons present in plants species after 20 days taken up from the treated soil. Plants planted in 100 mgkg-1 concentration were analysed and lowest toxicity observed in H. annuus which was 3.013 mgkg-1 Naphthalene, 7.750 mgkg-1 Phenanthrene and 5.691 mgkg-1 Anthracene while highest toxicity observed in Tagetes 8.476 mgkg-1 Naphthalene, 0.398 mgkg-1 Phenanthrene and 0.416 mgkg-1 Anthracene. These results suggested that H. annuus can be adopted in phytoremediation of hydrocarbons soil.