Changes in Enzyme Activities of Rice with Respect to the Viviparity and the Duration of Lodging Time

The Japonica cultivar 'Janganbyeo' was cultivated and about half of paddy field was totally lodged at 30 days after heading. Both lodged paddy and unlodged paddy were harvested at intervals. The lodged paddy and brown rice did not show any signs of viviparity until the $4^{th}$ day of lodging. The activities of $\alpha$-amylase, diastase, and lipase of lodged paddy and brown rice began to increase on the $2^{nd}$ day of lodging and then increased slowly afterwards. The activities of protease and phytase of lodged paddy and brown rice reached the maximum values on the $2^{nd}$ day and then decreased until the final day of lodging. In contrast, unlodged paddy and brown rice showed relatively small increase in viviparity and in activities of $\alpha$-amylase, diastase, protease, lipase, and phytase. Especially, activities of diastase and lipase were observed even in unlodged paddy and brown rice.