Fig. 3

In vitro culture establishment of beech via whole shoots and shoot tips of seedlings. a Seeds collected from Grosshansdorf (DE) were germinated in March in a plant growth chamber in cultivation soil. Once the first true leaf pair fully expanded, the leaves were removed, and the shoots were sterilized. The plants were divided into whole shoots (WS) and shoot tips (ST) and cultured on WPM with 2% sucrose and 0.65% agar, pH 5.6, supplemented with no hormones (M0) or different hormone concentrations (M2, M2.1, M2.2, and M3). b Bud break on cotyledonary nodes (white arrow) after 4 weeks of culture. c–f Explant phenotypes after 8 weeks c on M0 and d on M2. Some explants on M2.2 and M3 showed e hyperhydricity or f chlorosis. g Shoot multiplication occurred via axillary branching after 12 weeks. h Explant with resting buds (black arrow) after 12 weeks. i–k After 8 weeks, explants on M2, M2.1, M2.2, and M3 were transferred to M2, whereas M0 explants remained on M0. The groups were named according to their initial media. Analyses based on the media used were conducted for i percentage of vital shoot-forming explants after 4, 8, and 12 weeks (ST and WS were pooled). Box plots show j the median number of shoots per explant and k shoot length after 12 weeks. Each dot represents data from a single explant, with ST and WS differentiated by color. Significant differences from medium M0 were determined by i Pearson’s Chi-squared or j, k Dunn’s test (*p < 0.05, **p ≤ 0.01, ***p ≤ 0.001)