Rice plant tolerance response to the exposure of heavy metals and its Impact on Plant Overall Morphological and Histological Features

Abstract

Heavy metals bioaccumulation in the food supply chain is a critical environmental issue, required drastic action plans for health risk reduction. In this study, we aim 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 metal of Cd, Zn and Fe, while the combined metals were Cd+Zn, Cd+Fe and Zn+Fe, each at 5 different concentrations on 21st day of the germination. The results showed that all single and combined heavy metals upon solo and multiple exposures have a significant effect to the plant growth, where heavy metals influence root length, stem length, tree height, number of leaves, number of tillers, number of root hairs and total rice yield. The heavy metal content in paddy plants were in the order of root>stem>grain>leaf. CO2 influences the growth of rice plants, but the effect of heavy metal exposure has influenced the rate of growth. A positive correlation was obtained between single exposure and double exposure in soil and paddy plant. The accumulation of single and combined heavy metals in greenhouses and CO2 greenhouses alters the cell structure and tissues of rice plants. Our findings also suggested that paddy plant has the ability to regulate its internal structure and adapt to high accumulation of heavy metals in plant structure, seemed to have some degree of tolerance to heavy metals.