AN EFFICIENT PLANT REGENERATION SYSTEM VIA DIRECT ADVENTITIOUS BUD FORMATION IN CHICORY

An efficient plant regeneration system through direct adventitious bud formation is established using leaf segments of asepsis seedlings of chicory(Cichorium intybus L.).After 5～7d of culture,adventitious buds appeared directly from explants without any intervening callus on Murashige and Skoog(MS) medium supplemented with different concentrations of N-6-benzyladenine(BA) alone or together with 0.5mg/L α-naphthaleneacetic acid(NAA).According to histological observations,adventitious buds were originated from thin wall cell of vascular bundle of the leafs,and the vascular bundle systems of adventitious buds are closely connected with that of leaf explant.6-BA was necessary for direct adventitious bud formation.The frequency and number of adventitious bud formation were strongly influenced by the development stage of explants and sucrose concentration.After 15 days culture,the 100% frequency of bud formation as well as an average of 36～38 adventitious buds per explant were obtained on MS medium supplemented with 2.0mg/L 6-BA,0.5mg/L NAA,100mg/L Vc,100mg/L V_(B1),300mg/L proline and 40 g/L sucrose using 20-day-old leaves.When transplanted and cultured for about 10d on the 1/2 MS medium added 0.5mg/L indole-3-butyric acid(IBA), 97.58% rooting frequency was obtained.Plantlets grew well and appeared normal with no mortality after transfer to soil.