In Vitro Axillary Bud Sprouting And Proliferation Of Fraxinus Mandshurica Rupr.

The proper sterilizing method, basic media and hormones for in vitro axillary bud sprouting and shoot proliferation of Fraxinus mandshurica were studied. The explants were stem cuts with apical bud or axillary bud from 1 -year-old seedlings. Shoots and plantlets were obtained for the first time through in vitro axillary bud proliferation. The study made a solid foundation to establish a rapid micropropagation system of Fraxinus mandshurica.The stems with axillary buds or apical buds from one-year old seedlings were collected once per month for in vitro axillary bud sprouting. Results indicated that young stem collected during May to June can be well sterilized, the comtamitation rate for these explants is low (6-10%); young stem cutting from water-cultured super seedlings can be best sterilized, the comtamitation rate is lower than 6.5%. Sterilizing the buds with 0.05% HgCl₂ for 2min resulted in the lowest contamination rate. It was better for vertically implanting explants in the medium than horizotally inplanting ones. The stem with axillary buds is better than that with apical buds. Axillary bud can get more germination in WPM with 8.0 mg/L BA + 20 g/L sucrose + 7. 0 g/L agar and the bud sprouting rate for this treatment could reach 100%.For promote the axillary bud sprouting, we attempted treating them on the high voltage electrostatic field. The results indicated that the treatment of 0¹50 kv/m voltage electrostatic field in 30⁹0 min can promote in vitro axillary bud spouting. However, the axillary buds turn brown seriously, survival rate reduced.In the study of axillary buds proferation, shoot clusters could be obtained by transplanting the new shoots from sprouted axillary buds onto WPM. The statistical results showed that high inducing rate can reach 90% on medium containing 0.1 mg/L NAA+10 mg/L ZT. The proliferation rate could reach 2.75.Roots of sterile plantlets from F. mandshurica induced relatively easy. Sterile plantletsrooted through direct ways. Auxin treatments appeared to be essential for rooting. Whilecytokinin inhibited rooting. NAA has better effect than IBA does. The optimistic concentrationwas 0.5 mg/L when the best rooting rate was 65.4%. Rooted plantlets were easy to surviveafter acclimation.