FLORAL DETERMINATION IN ADVENTITIOUS SHOOT MERISTEMS REGENERATED FROMLEAVES OF DAY-NEUTRAL TOBACCO

The developmental patterns of adventitious shoots regenerated from cul tured leaf tissue and the petioles of leaf cuttings of flowering day-n eutral tobacco plants were assessed. Leaf tissue, removed from leaves within the inflorescence, was cultured on hormone-free medium and prod uced a limited number of adventitious shoots. These shoots produced th e same number of nodes that would be produced by a seedling meristem. Most leaf-cutting derived shoots produced the same number of nodes tha t would be produced by a seedling meristem prior to flowering, while a few shoots produced very few nodes and flowered. Some plants appeared to be intermediate in response. Results indicated that the developmen tal, state or the developmental response of all petiole cells is not t he same. The influence of position and the potential reversibility in developmental fate of cell populations within leaves is discussed in t he context of existing theory.