The application of different reproduction techniques for rare species waterlily tulip (Tulipa kaufmanniana Regel.) propagation under ex situ conditions

Abstract

T. kaufmanniana is a threatened and endemic species of the Tien Shan Mountains with a complex of valuable ornamental features. However, the commercial usage of the plant is limited due to the restricted availability of the bulbs in nature, difficulties in overcoming seed dormancy and low efficiency of the species reproduction. Results of the investigation of the reproductive biology of this species in the culture conditions allowed us to characterize T. kaufmanniana as viable with successful seedage. In the work reported here the effect of low temperature on the proper development of embryos is addressed, and an attempt is made to clarify the effect of cytokinins (TDZ, BAP) and auxin (NAA) on the regeneration capacity of isolated T. kaufmanniana embryos for the adventitious shoots and bulblets formation. Direct shoot organogenesis was induced by the combined action of chilling and BAP or TDZ treatment. Among the variants tested, TDZ promoted the formation of adventitious bulbs in 48 % of the chilled embryos, compared to non-chilled embryos (0.0%) and embryos exposed to the same concentration of BAP (39%). The best culture condition for T. kaufmanniana embryos growth and bulblets formation consisted of chilling for 10 wk in the dark at 4 °C, 4 wk at 20 °C under 16 h light photoperiod and 10 wk at 4 °C in the dark. Sufficiently effective protocol for clonal micropropagation was developed for the first time for T. kaufmanniana by the use of immature zygotic embryos as primary explants.

Keywords

• Tulipa species
• seed production
• embryo culture
• immature zygotic embryos
• chilling
• bulblet formation