POLYAMINES AS MARKERS FOR JUVENILITY IN FILBERT
As in other woody species, mature filbert (Corylus avellana L.) tissues, being the most interesting for micropropagation and breeding, has a reduced morphogenic capacity; therefore, cloning of selected mature individuals, both through asexual propagation and in vitro techniques, has several barriers to overcome. Maturation affects several tree features, from what the selection of interesting individuals is not possible during the juvenile phase of tree growth. Despite of recent investigations, little is known about physiological and biochemical processes accompanying the age effect on plant material. Levels of polyamines were higher in juvenile than in adult leaves, being putrescine the main polyamine in showing correlations with the age of the plant material. The ratio putrescine to polyamines increases in relation to the age, and correlates with the morphogenic capacity of the plant material. On the other hand, spermidine is higher in adult plant material which could be related to the reproductive maturity of this plant material. With tissue cultured material, levels of polyamines, mainly putrescine, also increased with repeated subcultures, but decreasing after a certain number of them. This must be related to the lost of morphogenic competence in aged cultures, being necessary to reinitiate the micropropagation programme. In fact, we observed a decrease in the proliferation rate in filbert after two years of continuous subculturing. The presented results can allow to establish a simple assay to test the juvenility degree in filbert tissues, allowing a better control on the initiation of micropropagation programmes from selected mature individuals.
Rey, M., Díaz-Sala, C. and Rodríguez, R. (1994). POLYAMINES AS MARKERS FOR JUVENILITY IN FILBERT. Acta Hortic. 351, 233-238