Q. Yang et S. Laliberte, CELL-DIVISION AND MICROCOLONY FORMATION IN PROTOPLASTS FROM MATURE MATERIAL OF HYBRID LARCH (LARIX X EUROLEPIS HENRY), PLANT SCI, 117(1-2), 1996, pp. 159-165
Protoplasts were isolated from needles of in vitro shoots initiated fr
om short shoot buds of stecklings from an 8-year old hybrid larch (Lar
ix x eurolepis Henry) tree. Protoplast yield and viability have reache
d, respectively 8.8 x 10(5) protoplasts/g fresh weight and 91.8% when
needles were enzymatically digested for 16 h in osmoticum containing 0
.5% Cellulase R-10, 0.5% Macerozyme R-10 and 0.5% BSA. First cell divi
sions were observed after 2 days of culture in a modified liquid (or s
olid) Murashige and Skoog medium (MSG) containing 2 mg/l 2,4-D and 0.5
mg/l BAP. After 1 week, 15-25% of the protoplasts had divided, and so
me had formed microcolonies with a plating efficiency from 3.9-7.9%. P
rotoplast-derived cells which had undergone division were concentrated
mainly in size classes between 25.0 and 44.5 mu m, and division frequ
ency increased with diameter.