title: Improved survival after cryogenic exposure of shoot tips derived from in vitro plantlet cultures of potato.
abstract: In vitro plantlets were used for axillary shoot tip isolation to avoid microbial contamination which often occurred from use of greenhouse-grown plants. Periodic subculturing gave a supply of uniform plantlets necessary for obtaining shoot tips for cryogenic experiments. Previous results have shown that all cells within a shoot tip did not survive cryogenic exposure and the regrowth percentage depended upon the composition of the culture medium. A medium containing 0.5 mg/liter zeatin, 0.2 mg/liter gibberellic acid, and 0.5 mg/liter indoleacetic acid gave regeneration of a multiple-shoot mass from control and some frozen shoot tips. The two-step cooling procedure (0.2-03 degrees C/min to -35 degrees C followed by immersion in liquid nitrogen) gave high percentages of regrowth in the cultivars Norland and Red Pontiac. Shoots were obtained from treated materials in both cultivars.
mesh_terms: D003451:Cryoprotective Agents / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D005615:Freezing; D005990:Glycerol / Q000494:pharmacology; D018521:Plant Physiological Phenomena; D010944:Plants / Q000187:drug effects
chemical_list: D003451:Cryoprotective Agents; D005990:Glycerol; D004121:Dimethyl Sulfoxide