Slow Growth Cultures - Slow-growth of plantlets ill vitro provides an attractive alternative to freeze preservation of germplasm as it is simpler, cheaper and very effective. Slow growth may be achieved by maintaining the plantlets either at a low temperature (4-9°C or Ca. 15°C) or on a medium having high osmotic concentration (e.g., 20% sorbitol or sucrose) or both.

In addition, the nutritional status of the medium may be lowered to restrict the growth of plantlets. Under the conditions of slow-growth, cultures may be attended to only once in several months, and subculture may, be necessary only after votary long periods" say, once every 12-36 months.