In all developmental stages of rice growth, paddy soil has to undergo the changes of moisture regime, such as flooded and nonflooded conditions in accordance with local practices.
Flooding occurs during early growth stages while non-flooding rice soils are present during late growth stages. Data generated in this study showed that allelopathic rice PI312777 released much higher concentrations of allelochemical 5,7,40-trihydroxy-30,50-dimethoxyflavone than non-allelopathic rice Liaojing-9 at early growth stages in flooded soil, whereas the flavone activated enzyme activities of flooded soil.