In 1902, Haberlandt published on his unsuccessful but pioneering attempt to cultivate cells from leaves of several angiosperms (5). Today, nearly 75 years later, plant cell and organ cultures are established as potent research tools and economical agricultural practices. Cell cultures enabled the demonstration of totipotentiality of plant cells as Haberlandt first suggested (22). Furthermore, they played a critical role in the discovery of cytokinins, an important group of plant hormones (8). Cell and organ cultures provide unique systems to explore organ initiation (17), cell and tissue differentiation (21), and other morphogenetic processes. They furnish new opportunities in somatic cell genetics (2). Organ growth and development can be studied with minimum interference by correlative influences (1, 14, 18, 19, 24).