MEDIUM SUPPLEMENTS AND SUPPORT MATRICES FOR BETTER IN VITRO GROWTH OF DATE PALM (PHOENIX DACTYLIFERA L.)
Despite its extensive use as gelling agent for tissue culture media, agar possesses many shortcomings including impurities, scarcity and high cost in local markets and sensitivity to the harsh local environment. In view of the need to find alternative gelling agents or solid support matrices, growth and development of date palm (Phoenix dactylifera L.) cultures were evaluated on polyurethane (PU) foam discs in comparison with agar-gelled medium. Incorporating activated charcoal in tissue culture media has been shown to affect growth and development of various organisms. It plays a critical role in the micropropagation of date palms by adsorbing inhibitory compounds in media and decreasing toxic metabolites, phenolic exudation and brown exudate accumulation. However, in some cases activated charcoal adsorbs hormones required for the callus growth and shoot development thereby retarding active growth. A comparative study of in vitro growth responses of two date palm cultivars in the medium containing charcoal and no charcoal showed significant differences in all the growth parameters. Date palm cultures growing on PU foam showed significantly superior rates of shoot multiplication and shoot elongation as compared to cultures in agar-gelled media. The rooting response of cultures on PU foam and agar-gelled media was nearly similar. It is argued that enhanced aeration and better suited physical characteristics of the material may be the reasons for superior performance of PU foam as support matrix in comparison with agar. It is therefore suggested that a polyurethane matrix can be used satisfactorily for micropropagation of date palms. The poor response of date palm cultures in the charcoal containing medium may be attributed to the lowering of pH of medium during autoclaving as reported by earlier workers thereby inhibiting the uptake of required growth regulators. Polyurethane can also be used for special applications where low pH of culture medium is required, and its composition and resulting physical properties may be precisely modified during manufacture to suit specific culture requirements. At the same time the matrix is very cheap as compared to agar even in a single use cycle.
Al-Khalifah, N.S., Khan, F.A., Askari, E., Hadi, S. and Shanavaskhan, A.E. (2010). MEDIUM SUPPLEMENTS AND SUPPORT MATRICES FOR BETTER IN VITRO GROWTH OF DATE PALM (PHOENIX DACTYLIFERA L.). Acta Hortic. 882, 815-825
polyurethane foam, support matrix, date palm, tissue culture, micropropagation, activated charcoal, phenol