IN VITRO PROPAGATION OF Quercus sideroxyla FROM MATURE ACORNS

Abstract

Quercus sideroxyla is used to produce firewood, carbon and paper pulp. However, there are no management programs for replacing plants, so their conservation status is in danger in some areas of Mexico. The aim of this study was to develop an efficient methodology for in vitro propagation of Q. sideroxyla. Acorns in the fruiting season were harvested and then analyzed by X-ray. The embryos were induced to germination (stage 1), induction of adventitious shoots (stage 2) and rooting in culture media (stage 3). Four concentrations of Quoirin-Lepoivre medium (QL 10, 20, 30, 40%) were used with and without activated carbon (AC), as well as silver nanoparticles (AgNp) in stage 1. Whilst in stage 2 and stage 3, only the best resulting QL concentration was tested with three concentrations of 6-benzylaminopurine (BAP) and naphthalene acetic acid (NAA) as growth promotors. Experimental analysis in germination was carried out as a completely randomized block design, 16 treatments with five replicates and the Fisher test (p?0.05) for means. Joint analysis of germination and shoots induction included a principal component analysis (PCA); induction and rooting of shoots were analyzed with the Wilcoxon paired analysis. The best results in the germination stage were observed in the treatment QL 30%, where 70% of germinated explants were obtained; but this treatment was not statistically different to the treatment QL 40%, which produced about 65% germination. In the remaining concentrations, explants oxidized completely; thus, a negative correlation medium-germination was observed. For multiple shoots induction stage, the best treatment was the lowest concentration of BAP:NAA which showed a positive behavior in the presence of activated carbon. Activated carbon on culture media, inhibited the oxidation of acorns and promoted the adventitious shoots and roots growth. This is the first report of the successful micropropagation of Q. sideroxyla. Using QL medium, activated carbon, silver nanoparticles and growth regulators promoted explant germination, rooting and vegetative development.