CELL-WALL COMPOSITION AND MORPHOGENIC RESPONSE IN CALLUS DERIVED FROMPROTOPLASTS OF 2 FIBER FLAX (LINUM-USITATISSIMUM L) GENOTYPES

Cotyledonary protoplasts of two French fibre flax (Linum usitatissimum ) cultivars (Ariane and Viking) were isolated and cultured. The optima l conditions for high yield were from 4-5 day old seedlings, where 6-6 .5 x 10(6) and 6.7- 7.4 x 10(6) protoplasts were released from cv. Ari ane and cv. Viking respectively. Culture in glutamine (20 mM containin g medium led to first divisions after 2 days with an efficiency of 19% or 21.9% (cv. Ariane) and 49.3% or 44% (cv. Viking) of divided cells, when plating densities were 10(5) versus 5 x 10(4) protoplasts per mL . Rhizogenesis occurred on protoplast derived calli at high frequency 4 weeks after transfer onto solid medium supplemented with 0.5 muM 2.4 dichlorophenoxyacetic acid. Variations of cell wall sugar composition during culture on inducing and non-inducing media expressed some sign ificant differences. The percentage of galacturonic acid increased on non-inducing medium, but remained constant on root-inducing medium. Gl ucose presented a peak of accumulation concomitant of the emergence of the root meristems 4 weeks after transfer onto 2,4-D containing mediu m. On the contrary galactose and arabinose variations were not charact eristic of the rhizogenic process.