Cytomorphological studies on somatic embryogenesis of Gentiana tibetica (King) and G. cruciata (L.)

The process of plant regeneration via somatic embryogenesis of two gentianas, <em>Gentiana tibetica</em> and <em>G. cruciata</em> was described. For this purpose seedling explants were cultured on agar medium and later maintained in cell suspension. For callus initiation seedling explants like: cotyledons, hypocotyl and root were plated on a callus induction medium (CIM) composed of MS (1962), supplemented with 0.5 mg/l 2,4-D and 1.0 mg/l Kin. For the formation of cell suspension culture, embryogenic callus was transferred into liquid maintained medium (MM) composed of MS (1962), supplemented with 1.0 mg/l Dic + 0.1 mg/l NAA + 2.0 mg/l BAP + 80.0 mg/l SA. The conversion of somatic embryo into plantlets required a new medium (ECM) based on MS (1962) mineral salts, supplemented with 0.5 mg/l GA₃ + 1.0 mg/l Kin + 0.5 mg/l NAA. For cytomorphological studies of particular stages of embryogenesis, specimens were stained with dyes and reagents: 1. PAS reaction with leukofucsin, 2. Safranin + fast green, 3. Erlich's hematoxylin.