The article presents the results of work on preservation of plant tissues and organs of rare and endangered species in conditions of slow growth. Special attention is paid to modeling objects, Silene cretacea and Potentilla volgarica – obligate calcifythes enlisted in the Red book of the Russian Federation. Slower growth of the explants was provided by reducing the cultivation temperature to +5±1 C and introducing into the nutrient medium of osmotic (sucrose 30, 60 or 90 g/l), retardant (chlorcholinechloride) and/or sorbent (activated carbon). It is established that the deposition of S.