Prolific direct plant regeneration from cotyledons of white clover.

A facile procedure has been developed to regenerate white clover (Trifolium repens L.) plants, rapidly and directly from cotyledon explants of 3 day old seedlings. Scanning electron microscopy and histological sectioning demonstrated that shoot meristems developed from individual epidermal cells on the adaxial surface of the cotyledonary stalk, proximal to the site of excision. Initial cell divisions occurred after 2 days of culture and regenerated plants were transferred to soil within 6-8 weeks. Regenerated plants were normal, flowered and set seed. The highest shoot regeneration frequency (an average of 20 shoots per cotyledon) was obtained using an MS based medium containing 1.0 mg 1(-1) 6-benzylaminopurine and 0.05 mg 1(-1) α-napthaleneacetic acid. A similar regeneration frequency was obtained from cotyledon explants taken from eight different white clover cultivars.