DOUBLE AND SINGLE HEAVY METALS POLLUTION EFFECT ON PADDY PLANTSITI FATIMAH SALIM, KHAIRIAH JUSOH, CHE RADZIAH CHE MOHD ZAIN, NORAINI TALIP AND MOHAMMED BELAL HOSSAIN
Effects of heavy metals single exposure (Cd, Zn, Fe) and double exposure (Cd+Zn, Cd+Fe and Zn+Fe) on the structural and morphological characteristics of paddy plant (Oryza sativa) was carried out at the green house and Open Roof Carbon Dioxide Glass House, UKM Bangi. The objectives of the study were to determine the effects of heavy metals exposure in morphology, to determine the concentration of heavy metals in paddy plant (root, stem, leaf and grain) and structural changes beside the correlation between the accumulation of heavy metals and anatomical changes. Scanning Electron Microscope (SEM) and Light Microscope (LM) were used to study the changes of morphological and structural of paddy plant. The results in this study showed significant effects of single exposures and double exposures. Leaf chlorosis, decreases of roots, tiller number, number of leaf, number of root hair and shoot height of the paddy were detected after single and double exposures of heavy metals. SEM studied for the paddy plant showed cell degeneration, cell walls thickening with the increasing numbers of treachery elements in the vascular cylinder in paddy root, degeneration of epicuticular wax, inhibition of stomata opening in paddy leaf surface, within breakdown of vascular bundles followed further losses of cells shape by Cd, Cd+Zn, Cd+Fe and Zn+Fe exposures. Compact epidermal and mesophyll cell walls within paddy leaf internal structure were also observed. LM studied showed dark deposits in the endodermis cells and vascular cylinder, rupture in the arenchyma tissue mainly with Cd exposure, and reduction in parenchyma tissue with Cd+Zn, Cd+Fe and Zn+Fe exposures, and dark deposits with cell walls thickening with Cd exposure. Results from this study indicated that paddy plant has the ability to regulate its internal structure and adapt to high accumulation of heavy metals in its plant.