A Regeneration Protocol for Spinacia oleracea Using Gibberellic Acid

Abstract

A reliable plant regeneration procedure by organogenesis has been obtained for Spinacia oleracea L. cv. Hybrid 102. The optimum procedure utilises a sequence of three different media. Explants from sterile seedling cotyledons or hypocotyls are incubated for 4 weeks in the dark on medium containing 4.6 μM kinetin and 4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D). The calli are then transferred to medium without 2,4-D but containing kinetin and gibberellic acid (GA₃). From this point on, incubation is in the light. A number of passages (usually three) of 4-6 weeks are required on this medium for shoot formation to occur. Calli destined to form shoots usually first undergo some root proliferation ('rooty calli'). Shoots can be induced to form roots by transfer to hormone-free medium. It is suggested that GA₃ stimulates the development of shoot primordia induced by 2,4-D. The presence of kinetin (but not 6-benzylaminopurine) results in more rapid shoot formation.