Influence of growth regulators (IBA, BA) on anatomical and morphological changes in bromeliads in in vitro culture

Abstract

The subject of study were <em>Tillandsia coronata</em> and <em>Guzmania monostachya</em>. The material has been obtained by means of in vitro propagation. The plants were grown for 18 weeks on various kinds of media. Morphological changes were recorded in both species subjected to action of growth regulators. The changes in plant habit were linked with anatomic build. The effect of cytokinin BA upon growth of the stem pith was found, transversely to its axis, through development of numerous meristematic centres and growth and development of adventitious shoots. Leaves of plant grown on media containing cyto-kinin BA were build of a higher number of cell layers of assimilation parenchyma. In plants grown on media with addition of cytokinin the size of stomatal cells was smaller and was accompanied by analogous changes in size of epidermis cells proper. The bushy type of the plants, caused by presence of cytokinin in medium, resulted from the increase of thickness and breadth of leaves and growth of the stem pith, with simultaneous inhibition of cells' elongation. Auxin IBA did not favour the growth of the existing axillary shoots, but stimulated elongation of the stem pith. The stomata of plants of both species grown on media with addition of auxin were bigger. As result of the applied growth regulators a higher frequency of appearance of binucleate cells was found in parenchyma cells of the stem and leaves in both the species studied.