Successive media to improve the in vitro rhizogenesis of Nothofagus nervosa (Phil.) Dim. et Mil.

G MARTÍNEZ PASTUR; M ARENA; N CURVETTO; D ZAPPACOSTA; E ELIASCO

NEW FORESTS

Año: 2003 p. 201 - 215

0169-4286

In vitro rooting constitutes a difficult step during the micropropagation process of forestspecies. The successive media culture technique represents one way to overcome this barrier and includesmodifying physical (e.g. photoperiod) and chemical (e.g. flavonoids) factors during the rooting phases.The aim of this study was to obtain a successive media protocol based on the incorporation of flavonoidsduring the in vitro rooting of Nothofagus nervosa. The factors evaluated were the type, concentration, andcombination of flavonoids in relation to the rooting phases, the presence of IBA in the culture medium,the photoperiod, and the effect of flavonoids on total tissue peroxidase activity. The photoperiod usedincluded a darkness period during the rooting induction stage and the presence of 0.61 mM IBA in theculture medium. The results showed that flavonoid incorporation at a concentration of 20 mM acceleratedthe appearance of roots and improved the quality of the already formed ones. Each type and concentrationof flavonoid produced different responses, with (6)naringenin giving the best results. The latter caused apeak in the peroxidase activity that was absent in the control treatments. This work allowed identifying anoptimized rooting protocol through a successive media culture technique that improved the speed ofappearance, as well as the quantity and quality of roots for a single N. nervosa clone.