The Control of Adventitious Root Production in Tissue-Cultured Douglas-Fir

1989

S. 1322-1329

10 Abb., 6 Tab., 25 Lit. Ang.

Unselbständiges Werk

200088434

Rooting percentage and root number in tissue-cultured Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were influenced by the rooting substrate, the concentration of sucrose and boron in the rooting medium, shoot height, and shoot generation. Peat-perlite was a better substrate than agar, producing 70% compared with 0% rooted shoots, respectively. On peat- perlite, cell divisions were organized and were associated with tracheid nests, whereas on agar proliferation was unorganized and not restricted to the nests. A sucrose concentration of 4% was optimal for the production of nodular or rooted shoots. At 4% sucrose and 3 mg.L-1 boric acid, 100% of the shoots rooted, and the mean root number was 11. Rooting percentage and root number were significantly higher with shoots that were 3 cm tall than 2 or 1 cm tall shoots. Finally, it was found that shoot responses were more rapid in third and fourth generation shoots than in second generation shoots. At least 80% were rooted or nodular after 4 weeks, compared with only 36% from the second generation.