A REGENERATION PROTOCOL FOR SPINACIA-OLERACEA USING GIBBERELLIC-ACID

A reliable plant regeneration procedure by organogenesis has been obta ined for Spinacia oleracea L. cv. Hybrid 102. The optimum procedure ut ilises a sequence of three different media. Explants from sterile seed ling cotyledons or hypocotyls are incubated for 4 weeks in the dark on medium containing 4.6 mu M kinetin and 4.5 mu M 2,4-dichlorophenoxyac etic acid (2,4-D). The calli are then transferred to medium without 2, 4-D but containing kinetin and gibberellic acid (GA(3)). From this poi nt 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 occu r. Calli destined to form shoots usually first undergo some root proli feration ('rooty calli'). Shoots can be induced to form roots by trans fer to hormone-free medium. It is suggested that GA(3) stimulates the development of shoot primordia induced by 2,4-D. The presence of kinet in (but not 6-benzylaminopurine) results in more rapid shoot formation .