Abstract: A laboratory experiment was conducted to study the effects of mechanical stimulation on the physiological characters of rice plant. Mechanical stimulation decreased the permeability of rice leaf plasma membrane, but, with the increase of stimulation intensity and treatment time, the permeability presented an increasing trend. The leaf chlorophyll a (Chl-a) content was increased by mechanical stimulation treatments, while the leaf chlorophyll b (Chl-b) content presented a decreasing trend. Low intensity mechanical stimulation increased the activities of protective enzymes peroxidase (POD), superoxide dismutase (SOD), and polyphenol oxidase (PPO) in rice leaves. In mechanical stimulation treatments, the leaf 3indoleacetic acid (IAA) content was reduced with time, whereas the leaf abscisic acid (ABA) content and the root activity showed an opposite trend. These results indicated that mechanical stimulation could be one of the important reasons leading to the morphological and physiological variations of rice plant. The findings from this study could provide a theoretical basis to further study the effects and action mechanisms of mechanical stimulation on the rice plant growth in rice-duck farming system.

Key words: biomass, Neolamarckia cadamba, sewage sludge, heavy metal.