Abstract
The effects of diesel oil pollution on Thespesia populnea (L.) Sol. Ex. Corr. were investigated in a series of artificially and freshly
polluted sandy soil with 0, 0.5, 0.75, 1.0, 2.5, 4.0 and 5.0 mL diesel oil per 100g soil. Emergence of seedlings was impeded and
germination losses occurred at high diesel oil concentrations. All the parameters of seedling growth viz. height, number of leaves,
stem diameter, hypocotyl and epicotyl lengths, cotyledon area per seedling, area of the largest leaf, total leaf area per seedling and dry
biomass of shoot, root and seedling declined progressively with increase of diesel oil concentration in the rhizosphere. Chlorophyll –
a, b and total chlorophyll contents in fresh leaves declined significantly. Against control where around 10 internodes were produced,
under diesel oil pollution only six or at the most seven internodes were produced. Diesel oil shortened the internodes. Diesel oil
reduced the number of days of retention of cotyledons and primary and secondary leaves with the seedlings i.e., diesel oil pollution not
only enhanced the cotyledon abscission but also the abscission of primary and secondary leaves and even the tertiary leaves under
very high concentrations. In spite of the extreme diesel toxicity to T. populnea under very high diesel oil contamination, the plant
showed good potential of phytoremediation against diesel pollution in sandy soil contaminated up to 10, 000 ppm of petrodiesel.
