POLYAMINE EVOLUTION IN BUDS AND SHOOTS OF DOUGLAS-FIR (PSEUDOTSUGA-MENZIESII) AFTER THE TRANSITION FROM VEGETATIVE DEVELOPMENT TO SEXUAL DEVELOPMENT

After methanolic extraction and dansylation, polyamines (putrescina, spermidine, spermine) of shoots and buds of Douglas fir (Pseudotsuga menziesii) were separated using reverse phase high performance liquid chromatography (HPLC). They were quantified by fluorescence detection (fig 1). On plant material collected in fall, free polyamine levels were measured in morphologically distinct vegetative, male and female buds of ramets of one clone (1101) and in shoots (needles, stem, and buds) bearing only vegetative buds or vegetative as well as male and female buds of ramets of two clones (1101 and 1200). The distribution of polyamines was different between sexual and vegetative buds. Putrescine was the dominant polyamine in vegetative buds, while spermidine predominated in floral buds (fig 3). The highest concentration of spermidine was observed in male buds. Furthermore, spermine was only found in the sexual buds (fig 3). All polyamines also increased in the shoots bearing sexual buds (fig 4) compared to shoots with only vegetative buds. In general, the spermidine level was higher in buds than in shoots. Finally, the ratio between putrescine and spermidine in sexual buds as well as in shoots bearing these kinds of buds was much lower than in vegetative organs (tables I and II). The possibility of using these polyamine contents as physiological markers of sexual differentiation is discussed.