摘要：Medium pH that is one of the important factors of the physico-chemical environment during development of plant tissues in conditions of in vitro culture which is modifi ed during preparation of media, but also changes with developing explants. Th e present experiments were performed to monitor the changes of medium pH and to determine the e. ect of medium pH on physiological characteristics of mature Pinus sylvestris L. tissue cultivated in vitro . Th e fi nal changes of medium pH aft er addition of agar and autoclaving were towards alkalinity in the range of initial pH 3.0 to 5.5. Results of the experiments proved that in general cultivation of pine buds causes acidifi cation of the medium. Th e degree of acidifi cation of medium during cultivation depends on initial pH of medium, morphogenesis of explants and duration of cultivation period without transplantation. Lowered activity of oxidative enzymes in buds cultivated on more acidic medium and less necessity for acidifi cation to reach the equilibrium in medium pH suggest that a low initial pH is more suitable for successful pine bud morphogenesis
