Circadian rhythm of the clock gene expression in N. attenuata . Mean (± SE) levels of relative transcript abundance of (A)NaLHY, (B) NaTOC1, and (C) NaZTL in wild-type N. attenuata seedling (n=3) at each harvest time for two days under long day condition (LD, gray lines, 16h light/ 8h dark) and continuous light condition (LL, black line). Gray boxes depict the dark period of LD. A N. attenuata elongation factor gene was used as a control for constitute expression.