The growth of tulip tissues in vitro
Large numbers of adventitious shoots have been induced to form in vitro on floral stem sections of Tulipa gesneriana L. cultivar Merry Widow. In comparison with explants of scale and axillary bud, floral stem tissues showed the greatest potential for shoot production. A modified Murashige & Skoog medium contained inorganic salts and vitamins at full strength and supplemented with benzylamino-purine and napthalene-acetic acid at 1 mg‾1 induced shoots on 70%-90% of floral stem explants. The stage of development of the bulb was found to be an important factor in determining the ability of explants to regenerate shoots. The shoot producing potential of floral stem tissues was greatest during the 'dormant' phase of the bulbs, but the ability to produce shoots was lost once rapid extension growth and greening of the floral stem had commenced. Morphogenesis in vitro was found to be influenced by the origin of explants from within the floral stem. A study of endogenous plant growth regulators was made within the floral stem in order to elucidate their role in the organogenetic processes occurring in vitro. A study of histological and morphological development in vitro showed that the shoot-like structures arise from the epidermal cell layer and have the potential to form whole plants.