SHOOT, ROOT AND FLOWER MORPHOGENESIS ON TOMATO INFLORESCENCE EXPLANTS

Regeneration of de novo shoots, roots and flowers has been obtained on inflorescence explants of tomato (Lycopersicon esculentum Mill.). Indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and alpha-naphthaleneacetic acid (NAA) were added in a 3 x 3 x 3 factorial combination with kinetin, each at 0.001, 0.1 and 10-mu-M concentrations. Direct shoot formation occurred on media with 10-mu-M kinetin and 0.001-mu-M IAA or NAA. Root formation was observed on media with 0.1-10-mu-M IAA or or NAA. Flower formation occurred on elongated shoots with several leaves on media with 10-mu-M IAA and 0.1-mu-M kinetin. Shoot organogenesis was increased by substituting 10-mu-M zeatin or N6-benzyladenine (BA) for kinetin. Eleven tomato cultivars were tested for their ability to undergo de novo shoot regeneration on the improved medium. All tomato cultivars were capable of shoot morphogenesis with a mean number of shoots per explant that ranged from 1.3 ('Red Alert') to 5.3 ('Large Red Cherry'). Histological studies revealed that active cell divisions occurred in subepidermal and cambial tissue during the first week of culture. Meristematic centers of dividing cells were evident by day 14, and well-developed shoot apices and leaf structures were observed on 50% of the explants 28 days after culture initiation.