Hydrocarbon stress response of four tropical plants in weathered crude oil contaminated soil in microcosms

Abstract

Responses to hydrocarbon stress of four tropical plants Panicum maximum, Zea mays, Centrosema sp. and Pueraria sp. grown in crude oil contaminated soils (1%, 5% and 10% w/w) were evaluated in a green house. Plants’ percentage survival, shoot heights, biomass development, and phytotoxicity susceptibility were used as indicators of growth, stress response and hydrocarbon tolerance. Relative to control, shoot heights and biomass of plants reduced with increasing hydrocarbon concentration, but 1% w/w oil-in-soil, stimulated shoot heights (5.9% and 6.4%) and weights (21.9% and 2.3%) in P. maximum and Centrosema sp. respectively. P. maximum tolerated the contaminant stress with biomass yields of 113% and 57% of control respectively in 1% and 10% w/w oil-in-soil. All the plants had 100% survival in 1% w/w, but considerably reduced survival in 10% w/w oil-in-soil. These results show that P. maximum has great potential for phytoremediation of petroleum contaminated soil.

Keywords:

• Hydrocarbon contaminant stress
• Phytoremediation
• Phytotoxicity susceptibility

Acknowledgements

This work was partially supported by a grant from the Federal University of Technology, Owerri, Nigeria. The authors are grateful to Mr Ogbonnaya Obi of the Central Laboratory, National Root Crops Research Institute (NRCRI), Umudike, for his invaluable advice and technical assistance with some of the laboratory analysis of samples. They also wish to thank Miss Ihuoma Umezurumba of Plant Biotechnology Unit, NRCRI, Umudike, for her assistance during the plant growth studies.