Journal of Environmental Biology
pISSN: 0254-8704 ; eISSN: 2394-0379 ; CODEN: JEBIDP
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Abstract - Issue Sep 2008, 29 (5) Back
Ontogenetic changes in foliar features and psoralen content of
Psoralea corylifolia Linn. exposed to SO2 stress
S.Tanvir Ali Mahmooduzzafar1, M.Z. Abdin2 and Muhammad Iqbal*1
of Botany, Faculty of Science, Jamia Hamdard,
of Biotechnology, Faculty of Science, Jamia Hamdard,
(Received: Nov 29, 2006; Revised received: August 08, 2007 ; Accepted: August 23, 2007)
Abstract: Field-grown Psoralea corylifolia plants were exposed to 0.5 ppm and 1.0 ppm concentrations of sulphur dioxide gas and sampled for observation at the pre-flowering, flowering and post-flowering stages of plant ontogeny. One ppm SO2 concentration caused a significant decline in leaf number and leaf area per plant, total leaf dry weight, and the size and amount of midrib vasculature. The density and size of stomata decreased and many stomata were damaged. Interestingly, new epidermis developed over some of the damaged leaf stomata, thus showing a unique defence strategy against SO2 stress through dedifferentiation of the epidermal cells. Decline in the concentrations of leaf chlorophylls and carotenoids in treated plants were up to 20% and 29% respectively. Stomatal conductance, intercellular CO2 content and net photosynthetic rate lowered by over 52%, 20% and 35%, respectively, under the SO2 stress. Concentration of psoralen, a basic linear furanocoumarin known for its use in the treatment of dermal diseases, was highest (5.32%) in seeds and lowest (0.28%) in roots. It was heavily reduced in SO2? treated plants, the maximum decline occurring in seeds (86.70%) and leaves (56.27%). In the roots and shoots of the treated plants, it was low in pre-flowering stage, compared with the control, but showed a recovery during the post-flowering phase of plant growth.
Key words: Leaf vasculature,
Photosynthesis, Psoralea corylifolia, Psoralen
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