LAUSR

In order to better understand the physiological and technical aspects of yerba mate vegetative propagation, the present study sought to evaluate the rhizogenic capacity of apical and basal mini-cuttings from different genotypes (named A3, A7, F1 and F2) and the possible relationships between rooting and specific biochemical and anatomical aspects of the species. After 90 days under greenhouse conditions, the following variables were assessed: mini-cuttings rooting percentage, number of roots, roots length, callogenesis, mortality, sprouting and leaf retention. Mini-cuttings samples were collected at the time of planting and after 90 days in the rooting environment in order to investigate the aspects related to stem and roots anatomy as well as the levels of phenolic compounds (PC) and the activities of peroxidade (POD) and polyphenol oxidase (PPO) enzymes. Genotype A3 presented the best rooting performance (65.6% rooting) while F2 had the lower rooting rates (24.5%). Apical and basal mini-cuttings did not differ regarding rooting associated variables. Both mini-cuttings types and the four genotypes showed identical anatomical features, with no evident mechanical barriers to roots emission. Despite specific differences on POD, PPO and PC activities/contents as influenced by topophysis, genotype and/or their interaction, no direct relationship could be stated between the biochemical features at the time of planting or 90 days after and the overall rooting performance of yerba mate the mini-cuttings. The present study not only provides valuable information on technical aspects of yerba mate propagation but also presents insights in the physiological and anatomical traits of adventitious rhizogenesis in this species.