Extracellular matrix surface network is associated with non-morphogenic calli of Helianthus tuberosus cv. Albik produced from various explants

Abstract

<em>Helianthus tuberosus</em> is economically important species. To improve characters of this energetic plant via genetic modification, production of callus tissue and plant regeneration are the first steps. A new, potentially energetic cultivar Albik was used in this study to test callus induction and regeneration. Callus was produced on leaves, petioles, apical meristems and stems from field-harvested plants but was totally non-morphogenic. Its induction started in the cortex and vascular bundles as confirmed by histological analysis. The surface of heterogeneous callus was partially covered with a membranous extracellular matrix surface network visible in scanning and transmission electron microscopies. The results clearly indicate that: (<strong><em>i</em></strong>) the morphogenic capacity of callus in topinambur is genotype dependent, (<strong><em>ii</em></strong>) cv. Albik of <em>H. tuberosus</em> proved recalcitrant in in vitro regeneration, and (<strong><em>iii</em></strong>) extracellular matrix surface network is not a morphogenic marker in this cultivar.