Expression of beta-tubulin during dormancy induction and release in apical and axillary buds of five woody species

Cell cycle activity was studied in apical and axillary buds of Norway maple (Acer platanoides L.), apple (Malus 'M9'), pedunculate oak (Quercus robur L.), Scots pine (Pinus sylvestris L.) and rose (Rosa corymbifera 'Laxa') during dormancy induction and release. Flow cytometric analyses revealed that in dormant buds, cells mainly were quiescent at the G(0)/G(1) phase, while in non-dormant buds, a significantly higher frequency of G(2) cells was found in all species. In western blots accumulation of 55 kDa beta-tubulin was found in active growing plant material, whereas in dormant buds the accumulation was much lower or below detection level. It was observed for all species that during dormancy induction the amount of beta-tubulin decreased, while during dormancy release a fast accumulation of bern-tubulin occurred, The dynamics of the beta-tubulin accumulation reflected the dormancy status of tree buds of the five species studied suggesting that the beta-tubulin level might be useful as a marker for the dormancy status in buds of temperate woody species.