Tamiris Daros Salla;C. dos S. Silva;Kleiton Lima de Godoy Machado;Leandro Vieira Astarita;Eliane Romanato Santaré

Pontifícia Universidade Católica do Rio Grande do Su;Pontifícia Universidade Católica do Rio Grande do Sul

Adventitious shoots;Callus;Liquid medium;Micropropagation;Phenolic compounds;Rooting;TEMPORARY IMMERSION SYSTEM;MEDIATED TRANSFORMATION;SECONDARY METABOLISM;PLANT-REGENERATION;SALIGNA;MULTIPLICATION;EXPLANTS;CLONE

Eucalyptus is very recalcitrant to in vitro culture. In this research, an efficient shoot organogenesis system was developed using 60-day-old plants of Eucalyptus globulus grown in vitro and non-aerated liquid medium to improve shoot proliferation. Cultures were initiated with hypocotyls and leaf segments from plantlets cultivated on semisolid A 1/2 MS modified medium supplemented with 4.44 A mu M 6-Benzyladenine (BA) and 16.1 A mu M 1-Naphthaleneacetic acid (NAA). Calli were transferred to shoot induction medium, with either 0.5 or 2.7 A mu M NAA. Shoot multiplication was carried out on 4.44 A mu M BA + 0.5 A mu M NAA medium, and semisolid and non-aerated liquid systems were compared for improving shoot proliferation. Rooting of adventitious shoots was evaluated on medium containing NAA or Indole-3-butyric acid -IBA (5 and 16 A mu M). Callogenesis was obtained from both types of explants, although shoot formation was only obtained from leaf-derived calli. Shoot proliferation on 4.44 A mu M BA + 0.5 A mu M NAA resulted in the most shoots/callus. Non-aerated liquid medium was more efficient in promoting shoot multiplication (53.5 shoots/callus) than was semisolid medium (28.5 shoots/callus). Levels of phenolic compounds were significantly reduced in the shoots cultivated in liquid medium. Efficient rooting (76%) was obtained using 16 A mu M IBA.