In this communication are presented results of studying the effect of natural bioregulator Reglalg in combination with microelements B, Zn, Mn, Mo on the growth аnd photosynthesis characteristics of leaves, as well as fruit quality of plum late varieties of local selection Udlinennaia and Superprezident and introduced variety President. Investigations have shown the high responsiveness of plum trees on the exogenous processing, which was manifested in the stimulation of growth and net photosynthetic productivity of leaves, the accumulation of carbohydrates in plum fruits and their better storage.