Journal of Environmental Biology

Effects of heavy metal exposure on the morphological and microscopical characteristics of the paddy plant

A.M. Jamila Alfaraas, J. Khairiah, B.S. Ismail* and T. Noraini

School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia,

43600 UKM Bangi, Selangor, Malaysia

*Corresponding Author E-mail: ismail@ukm.edu.my

Publication Data

Paper received:

17 January 2014

Revised received:

10 August 2015

Re-revised received:

27 December 2015

Accepted:

19 March 2016

Abstract

The objective of the study was to determine the effects of heavy metal exposure on the morphology and anatomy of paddy plant (Oryza sativa L.). Paddy plants were treated with single and combined close of Cd and Pb (5, 10, 15, 20 and 25 ppm) at 35 days after germination. The results showed leaf chlorosis, decrease in number of roots and shoot height under both single and combined treatment. Heavy metal content in paddy was in the order of root>stem>grain>leaf and was highest at reproductive stage. A positive correlation was obtained between Cd, Pb and Cd-Pb concentrations in paddy plant parts with the concentrations of these metals in the soil. Scanning Electron Microscopic studies showed changes in the microscopic features due to accumulation of heavy metal and these included cell degeneration and thickening of cell walls, as well as increase in the number of treacherous elements in vascular cylinder and as residue in cells. Light microscope studies showed that Cd exposure caused dark deposits in the endodermal cells and vascular cylinder, as well as rupturing of parenchyma tissue. Results of the study indicated that paddy plants seemed to have some degree of tolerance to heavy metals.

Key words

Heavy metal, Metal accumulation, Morphology, Paddy plant

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