Apricot (Prunus armeniacana) is one of the important fruits in moderate regions. Progress in classical breeding of apricot is impeded by its complex genome and the long breeding cycle. Therefore, its improvement by classical methods of breeding is difficult and time-consuming. Protoplast transformation and culture is one of the suitable tools for breeding of this fruit. Different factors such as source of explants, plasmolysing pretreatment, digesting enzyme solution and digestion time affect the quantity and quality of isolated protoplast. The purpose of this study was to determine the effect of plasmolysing pretreatment and digestion time on frequency and viability of isolated protoplasts from leave mesophyll of apricot. In order to isolate the protoplasts, the leaves were plasmolised in sorbitol 13% under 3 time treatment (6, 9 and 12 h). Then, the leave mesophyll were incubated in enzyme solution that consists of cellulase R-10 (1%), Pectolyase Y-23 (0.1%, 0.2% and 3%) and macerozyme (0.5%, 1% and 2%) under five digestion times (10, 12, 14, 16 and 18). The results showed that quantity and viability of isolated protoplasts was significantly affected by plasmolysing, enzyme concentration, and digestion time. Plasmolysis of leaves for 90 min in a 13% sorbitol solution greatly increased the number of protoplasts obtained. The best of enzyme solution was consists of cellulase R-10 (1%), Pectolyase Y-23 (0.1%) and macerozyme (0.5%). After 16 h. enzyme treatment, 108 protoplasts with 85% viability was obtained, that this time is the best time-term treatment for protoplast isolation from mesophyll cells of apricot.
