Assessment of Growth Performance of Two Cultivated Okra Species (Abelmoschusesculentus (L.)) Moench and Abelmoschuscaillei (A. Chev.) Stevels) Exposed to Crude Oil Contaminated Soil

Abstract

Six accessions of cultivated Okra (Abelmoschuscaillei (A. Chev.) Stevels) and Abelmoschusesculentus (L.) Moench) were evaluated using growth parameters in crude oil contaminated soil. Seeds were collected from collected from Nigerian Institute of Horticulture (NIHORT), Ibadan and from home gardens in Benin City. Contaminated soil sample were collected from Nigerian National Petroleum Coperation (NNPC) substation in Auchi. The contaminated soil had higher concentrations of heavy metals than control soil obtained as top soil from the experimental garden of the Department of Plant Biology and Biotechnology, University of Benin. Morpho-agronomic characters such as numbers of days from sowing to germination, dry and fresh weight of the accessions in both soil sample was determined. Others were copper (Cu), Zinc (Zn), Manganese (Mn), Cadmium (Cd) and Lead (Pb) concentration in plant parts (leaves and fruits). The growth responses of the different accession varied considerably although A. esculentus accessions performed better. Soil chemical analysis revealed decreased levels of pH, Phosphorus and Potassium in the contaminated soil. The chemical analysis of plants grown in these soils showed that heavy metals like Cu, Zn, Mn, Cd and Pb were present in all the organs of the accession. These heavy metals accumulate in the tissue and make the plant unsafe for consumption. The study suggests that Okra diversity is vulnerable to crude oil contamination.

Key words: Crude oil, Soil, Growth parameters, Abelmoschusesculentus, A. Caillei, Heavy metals