Anthurium andraeanum Lind. is an economically important potted and freshcut flower species. However, reduced anthocyanin content under shaded cultivation impacts the color of the spathe, which has negative implications for the marketability of A. andraeanum. Thus, the present study evaluates the use of oyster shell supplementation to the cultivation medium for improving anthocyanin content. Appropriate calcium (Ca) can improve the activity of phenylalanine ammonia lyase (PAL), and PAL activity is positively correlated with anthocyanin content; ...