IN-VITRO CULTURE OF CUCUMIS-SATIVUS L .18. PLANTS FROM PROTOPLASTS THROUGH DIRECT SOMATIC EMBRYOGENESIS

A procedure is described for the isolation and culture of protoplasts from embryo,genic callus (gel-like callus GLC) and embryo, genic suspe nsion cultures (ESC) of Cucumis sativus c.v. Borszczagowski. Maximal p rotoplast yields from GLC and ESC were 5 x 10(6) and 1 x 10(7) protopl asts/g tissue respectively. They were obtained following 14-16 h diges tion with 1.2% Cellulase Onozuka R-10, 1.2% Macerozyme R-10 and 0.3% D riselase. At a plating density of 2 x 10(5) / ml, first divisions occu rred in 4-5 days and 7-8 days in ESC- and GLC-derived protoplasts resp ectively. The highest percentage of direct embryogenesis (over 80%) wa s observed with ESC. It was possible to obtain approximately 5000 embr yo structures / g tissue. Some embryos converted into plants after 6 w eeks, but most of them after 2 months of culture. ESC-derived plants, when transferred into the glasshouse, bloomed normally, and set seeds.