Developmental Anatomy of Adventitious Shoot Formation on Antirrhinum majus L. Hypocotyls In Vitro

Abstract

<jats:p>Adventitious shoot formation in vitro from <jats:italic>Antirrhinum majus</jats:italic> L. hypocotyls was investigated using two inbred lines, the most and least regenerative lines selected from screening. Time course analysis indicated cell division in the most regenerative line occurred first in one or a small number of epidermal cells with periclinal and anticlinal divisions. Subsequently, cortical then vascular cells were recruited beneath the dividing epidermal cells. Once shoots formed, their vascular system was continuous with the original hypocotyl explant. The least regenerative line had no cell division directed toward organogenesis. Shoot formation on hypocotyls of <jats:italic>A. majus</jats:italic> was adventitious in origin, by direct organogenesis and genotype dependent.</jats:p>