Not available – first paragraph follows: Plant cells without walls (protoplasts) can be isolated from leaves by a process of enzy-matically digesting away the middle lamellae between cells and the cell walls. Tremendously large numbers of protoplasts can be isolated from a single leaf; yields are typically two to four million protoplasts per gram of leaf tissue. Development of techniques and procedures causing isolated protoplasts to reform their walls, proliferate, and regenerate into whole plants is essential for the utilization of the new genetic technology.