Effect of gibberellic acid and ethephon on the germination of European beech dormant and chilled beechnuts

Abstract

The effect of ethephon (80, 100 and 120 mg·l<sup>–1</sup>) and gibberellic acid (GA<sub>3</sub>) (40, 300 and 1,000 mg·l<sup>–1</sup>) on the germination capacity (GC) and mean germination time (MGT) of European beech (Fagus sylvatica [L.]) dormant beechnuts or beechnuts pre-chilled for four weeks was determined. Compared to the control (dormant untreated seeds) or beechnuts treated with tap water no significant increase in mean GC was detected after the application of ethephon or GA<sub>3</sub> to dormant seeds. Conversely, both ethephon and GA<sub>3</sub> treatments reduced (ethephon significantly) GC when applied to beechnuts chilled for four weeks prior to treatment. The effect of the treatments on germination speed (MGT) and dormancy release significantly improved when beechnuts were chilled for four weeks prior to the application of ethephon or GA<sub>3</sub>. However, the effect of GA<sub>3</sub> on MGT of chilled beechnuts was not so distinct compared to dormant untreated seeds. Reduction in MGT was most obvious in seeds hydrated with 1,000 mg·l<sup>–1</sup> GA<sub>3</sub> prior to germination. Their cold requirement time was reduced by three weeks compared to beechnuts hydrated in tap water.