IN-VITRO PROPAGATION OF PEONIA-SUFFRUTICOSA ANDR CV MME-DE-VATRY - DEVELOPMENTAL EFFECTS OF EXOGENOUS HORMONES DURING THE MULTIPLICATION PHASE

In this work, the effect of various hormones on in vitro multiplicatio n and elongation of Paeonia suffruticosa is studied and several morpho logical and physiological abnormalities induced by them are described. Among the five cytokinins tested, only benzylaminopurine (BAP) allowe d the development of axillary buds. However, the concentration of this hormone and the age of the shoots used must be taken into account to avoid vitrification. Gibberellic acid (GA3) alone in the culture mediu m allowed neither shoot elongation nor leaf and axillary bud formation or development. The combination of BAP with GA3 increased the multipl ication rate as compared with BAP atone and allowed shoot elongation. This hormonal combination sometimes caused apical and leaf necroses, e specially under low Ca'' concentrations. Consequently, a BAP-GA3 mediu m is not recommended for regular use, although it can be interposed in a culture series on the BAP medium, to stimulate periodic axillary bu d development.