Plantlet regeneration from young leaf segments of curaua (Ananas erectifolius), an Amazon species.

The present study reports the first efficient in vitro regeneration of Ananas erectifolius via indirect organogenesis. Leaf segments (leaf base, middle, and apex) excised from 3- or 5-week-old in vitro plantlets were cultured on 1/4 strength MS medium supplemented with different concentrations and combinations of plant growth regulators. The explants were also exposed to pulse treatment with thidiazuron (TDZ) and 2,4-dichlorophenoxyacetic acid (2,4-D) for different periods of time. The results showed that using juvenile rather than old explants enhanced the frequency of callus induction (35.0% and 16.0%, respectively). Among the explant types tested, only leaf base segments induced calli; the highest frequency occurred via culture treatment containing 4-amino-3,5,6- trichloropicolinic acid (picloram; 48.57%), 2,4-D (40%), or TDZ (35.71%). However, only calli generated in treatments containing TDZ or N6-isopentenyladenine (2ip) were able to develop shoots (maximum 35.71% and 14.28%, respectively). A combination of TDZ and 2,4-D improved callus induction (60.0%) but did not increase shooting response. However, both callusing and shooting response increased when 10 days of pulse treatment with TDZ and 2,4-D was applied (66.83% and 48.7%, respectively). Rooted plantlets that exhibited normal growth and development were acclimatized in a greenhouse and had a survival rate of 95%. [ABSTRACT FROM AUTHOR]