INDEPENDENCE OF TISSUES DERIVED FROM APICAL LAYERS IN ONTOGENY OF THE TOBACCO LEAF AND OVARY

摘要: Six different homoplastidic periclinal chimeras of tobacco carrying the plastogene DP, were selected after somatic segregation in heteroplastidic seedlings. Direct observation plane division epidermal cells young leaves, and number size sub-epidermal green spots on leaves with Green-White-White (G-W-W) pattern variegation, indicated that ratio to anticlinal divisions L-J during development lamina was 1:3100. The white seedlings obtained from chimeral branches a similar frequency ovary. arrangement tissue mature various types extent participation by three apical layers initiation buttress, axis, formation lamina. During there must be independent initial-groups present. L-I L-II initials remain marginal, but early growth leading edge derived L-III becomes separated submarginal (L-II) products frequent initials. STABLE PATTERNS chlorophyll or plastid variegation have been observed utilized horticulturally for several hundred years. Their interpretation relationships meristem subject many investigations (Baur, 1930; Dermen, 1960; Clowes, 1961; Tilney-Bassett, 1963; Burk, Stewart, 1964; 1965; Neilsen-Jones, 1969; Stewart 1970). classical studies Satina (1944) Blakeslee (1941, 1943) Dermen (1947b, 1953) cytochimeras shown distribution derivatives can traced shoot its appendages. patterns correspond those (Dermen 1947a, 1960). ease which provides more extensive data origin tissues leaf their independence. Studies normal ontogeny outer layer (L-I) gives rise epidermis only. second over entire lamina, as well remaining internal an area irregular width around (Fig. 4). Tissue third (L-III) occupies 1 Received publication 6 April 1970. Cooperative Vegetables Ornamentals Research Branch, Tobacco Sugar Crops Division, Beltsville, Maryland. central, portion leaf. Plastid also pollen egg are normallv L-II. These established (Burk et al., 1964), poinsettia carnation (Stewart, 1965), other plants (Dermen, NeilsenJones, 1969). persistence stability depends upon independence shoot. This is maintained preponderant, if not exclusive, tunica contrast random planes corpus. There has comment literature occurrence consequences, few quantitative presented except (1970). Similarly consequences below st m appendages described, good estimates such available. Chimeras based mutant enabled us evaluate role MATERIALS AND METHODS-Seed self-pollinating DP1 (mutant DNA) plastids (G-M-G). potential chloroplasts letter