Changes in Ribulose 1,5-Bisphosphate Carboxylase Concentration due to External Nitrogen Supply in Mulberry Leaves (Morus alba L)

Effects of external nitrogen supply on quantity and activityof ribulose 1,5-bisphosphate carboxylase (RuBPCase) in mulberryleaves (Morus alba L. cv. Shin-ichinose) were examined. PhotosyntheticCO₂ fixation and the contents of chlorophyll and phosphoruswere increased by the increased N supply. RuBPCase-protein concentrationand its proportion to total soluble-protein or to total-N rosecorrespondingly as the N supply increased. Specific enzyme activityexpressed on a RuBPCase protein basis was not affected by theN supply. Morus alba L. (mulberry), N nutrition, RuBPCase protein content, photosynthesis