Use of polylactic acid microvessel to obtain microplantlets of Eucalyptus microcorys through indirect organogenesis

Microplants of Eucalyptus microcorys were produced through indirect organogenesis, and the interaction of plant growth regulators (PGRs) (TDZ-thidiazuron and NAA-α-naphthalene acetic acid), juvenile tissues (cotyledon and hypocotyl) and different types of polylactic acid (PLA) microvessels on plant production were evaluated. Cotyledon-derived callus induction increased by 30-60% in all tested combinations of TDZ and NAA concentrations compared the absence of PGRs. Hypocotyl-derived callus induction was improved in most tested combinations of TDZ and NAA concentrations. Moreover, 100% callus induction from both tissues was achieved with TDZ (1, 2 and 3 mg L^-1) + NAA (0 mg L^-1). Bud induction from cotyledon tissues was improved with TDZ (1 and 3 mg L^-1) + NAA (0 mg L^-1) and from hypocotyl with TDZ (1 and 2 mg L^-1) + NAA (0 mg L^-1). Shoot elongation from cotyledon tissues was not improved from any combination of PGRs, whereas TDZ (1 mg L^-1) + NAA (0 mg L^-1), TDZ (1 mg L^-1) + NAA (4 mg L^-1), TDZ (2 mg L^-1) + NAA (4 mg L^-1) and TDZ (3 mg L^-1) + NAA (2 mg L^-1) improved shoot elongation from hypocotyl tissues. Adventitious rooting and acclimatization of microcuttings ranged from 40 to 70% in three of the tested microvessels. The acclimatized microcuttings had low genetic variability. Successful production of E. microcorys microplants was achieved in this study using hypocotyl tissue and cultivated a culture medium supplemented with TDZ and NAA, using PLA-based microvessels.