Abscisic acid and 3-indolacetic acid levels during the reinvigoration process of Pinus radiata D. Don adult material

The maturation and phase change processes in woody species have not been completely clarified, specially the role of growth regulators during the maturation phase. Understanding their role better will allow to comprehend the physiological aspects of the species, which would allow to chose the optimal management conditions in forestry programs and make them more useful. In the present study, the endogenous content of abscisic acid (ABA) and 3-indolacetic acid (IAA) were quantified by high performance liquid chromatography, in the reinvigoration process of elite Pinus radiata material, during the development of homomicrografts (P. radiata/P. radiata) and heteromicrografts (P. radiata/Pinus caribaea), developed under in vitro conditions. The results showed an increase in the endogenous content of ABA through time and a decrease in the content of IAA. Significant differences were found in the endogenous content of ABA, where the maximum values were detected at 120 days of micrograft culture, being similar to the values obtained in juvenile buds. As well, significant differences were also detected in the endogenous content of IAA in the micrografted buds during all the development phases, compared with adult buds. However, no significant differences were detected in the endogenous content of ABA and IAA, regarding the type of rootstock employed. Considering the endogenous content of ABA and IAA, the micrografted plant material would be equal to the juvenile buds, since statistically they were equal to these buds, considering that the values obtained in this case are independent from the type of rootstock used.