Effect of High Temperature on Sucrose Content and Sucrose Cleaving Enzyme Activity in Rice Grain During the Filling Stage

Dynamic changes of sucrose, fructose, glucose contents and differences in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase in rice grain after flowering stage were studied under natural and high temperatures by using two japonica rice varieties Koshihikari and Sasanishiki. In rice grains, the sucrose synthase activity was higher than that of invertase, which was significantly correlated with starch accumulation rate, indicating that the sucrose synthase played an important role in sucrose degradation and starch synthesis. Under high temperature, the significant increase in grain sucrose content without any increase in fructose and glucose contents, suggested that the high temperature treatment enhanced sucrose accumulation, while diminished sucrose degradation in rice grains. Compared with the control plants, the decrease in activities of sucrose synthase, vacuolar invertase, and cell wall bound invertase with high temperature treated plants indicated that the deceleration of sucrose-degradation was related to the decrease in activities of sucrose synthase and invertase.

A rescaling method for correcting log-layer mismatch in detached eddy simulation

In order to correct the unphysical log-layer mismatch commonly encountered in detached eddy simulation(DES) of flows with attached boundary layers,a function M,ML,which has a multi-layer structure with scaling laws in each layer and a plateau related to the Kármán constant,is defined.The height of this plateau is found to be crucial for obtaining the correct log-layer.A target scaling function is designed which equals M,ML in the near-wall region,but with the height of plateau determined analytically from the classical log-law.This scaling function is used as a target function according to which the resolved turbulent fluctuations are renormalized,in order to recover the height of plateau prescribed by the log-law.The renormalization procedure guarantees the height of M,ML required by log-law,resulting in correct log layer slope.The method is also shown to maintain similar turbulent properties in the large eddy simulation(LES) region of DES method.Hence it predicts the turbulent intensity correctly.The results demonstrate the relationship between constant M,ML and log-law profile of mean velocity,and relate the Kármán constant to turbulent fluctuations,implying a complete description of turbulent structural ensemble dynamics.The proposed method can be extended to more general flows with log layers since it uses only the log-law with Kármán constant as the input,while the intercept of log layer depends on the solution of Spalart-Allmaras(SA) model in the near-wall field,where Reynolds-averaged Navier-Stokes(RANS) solutions are accurate.