Abstract

With the object of establishing mass production methods of Eucalyptus globulus, factors affecting its in vitro multiplication stage by temporary immersion were studied. For this, five microshoots per flask containing 250 mL of Murashige and Skoog medium were disposed. Factors such as immersion frequency (6, 12, 24, 48 h), immersion time (1, 2 and 3 min) and macronutrients concentration (25, 50 and 100 %) were studied. In a second stage, the addition into medium of 6-bencylaminopurine (0, 2.2 and 4.4 ?M), polyvinylpyrrolidone (0, 250 y 500 mg L -1) and sucrose concentration (43.8 and 87.6 mM) was analyzed. A completely random design with factorial arrangement was used in each stage. Variables evaluated were number of new shoots per flask, dry and fresh weight rate and final pH of culture medium. The best rate of multiplication and less hyperhydration was obtained with immersion time of 2 min, a frequency of 12hours, macronutrients at 50 %, 2.2 ?mol of 6-bencylaminopurine, 43.8 mM of sucrose and 250 mg L -1 of polyvinylpyrrolidone. Time and frequency of immersion interaction affects multiplication rate and microshoot hyperhydration. Use of 6-bencylaminopurine (2,2 ?M) and polyvinylpyrrolidone (250 mg L -1) increases multiplication rate without influence on microshoot hyperhydration. A reduction on sucrose concentration decreases hyperhydration without affecting formation of new shoots.