AGAR AS A GELLING AGENT - DIFFERENTIAL BIOLOGICAL EFFECTS IN-VITRO

The effect of seven agar brands (Merck, Daishin, Difco Bacto, MC 29, a nd Becton Dickinson grade A, granulated, and purified) on adventitious shoot and root regeneration, bulblet formation, and axillary shoot fo rmation was studied. Interactions were found between agar performance and plant species, and regeneration processes. Agar quality could affe ct, in principle, all developmental processes, the regeneration of adv entitious shoots and roots being the most sensitive. In well-establish ed cultures agar sensitivity was reduced. It appeared from experiments with 13 plant species that agars that can be identified that, in gene ral, exhibit either good, moderate or bad performance in most regenera tion systems. However, the best results with any regeneration system w ill be obtained when testing of some different types of agar is includ ed in the procedures for development of protocols. It was concluded th at it is not possible to develop a general bioassay for plant-grade ag ars. (C) 1998 Elsevier Science B.V. All rights reserved.