Propagation of Ornamental Plants
14(3): 101-111, 2014
IN VITRO BULBLET PRODUCTION AND PLANT REGENERATION FROM
IMMATURE EMBRYOS OF FRITILLARIA TUBIFORMIS GREN. & GODR.
Valentina Carasso1 and Marco Mucciarelli2*
1 Natural Park of the Marguareis Massif, 34 S. Anna Road, 12013 Chiusa di Pesio (CN), Italy
2 Department of Life Sciences and Systems Biology, University of Torino, 25 P. A. Mattioli Blvd, I-10125 Torino, Italy, *Fax +39 011 2369144,
Fritillaria tubiformis Gren. & Godr. is an alpine geophyte endemic to mountain prairies of the Southwestern Alps. To satisfy the need for ex situ propagation of this rare species, a simple and efficient protocol suitable for in vitro plant regeneration was developed. Immature zygotic embryos (IZEs) were employed as explant source of somatic embryos (SEs). In consideration of the low temperature requirement for germination of F. tubiformis, we studied whether cold stratification (30, 60, and 90 days of incubation at 4°C) affected in vitro bulblet regeneration. After one month of culture on MS medium, 30 and 60-day cold stratified IZEs begun to dedifferentiate, in contrast 90-day cold stratified embryos died. Callus proliferation was optimal in the presence of plant growth regulators in the medium. The number of somatic embryos positively correlated with callus, however it was more affected by the length of cold stratification than by the presence of exogenous plant growth regulators in the medium. The maximum number of SEs occurred in 30-day cold stratified zygotic embryos on MS2 medium. Transfer onto a maturation medium supplemented with 4% (w/v) sucrose was essential for the conversion of SEs into bulblets. In the presence of 4.92 µM IBA, bulblets sprouted and rooted and, newly established plants were available for pot cultivation. Greenhouse hardened plants were transferred to open air.
Key words: bulb formation, germination, plant regeneration, somatic embryogenesis