Rooting of Aegiphila Brachiata Cuttings: Anatomical, Biochemical and Metabolomic Characterization

Abstract

To improve the production process of Aegiphila brachiata cuttings, the objective of this study was to evaluate the rhizogenic potential of cuttings from rejuvenated and adult mother plants collected in different seasons; we also characterized anatomically the cutting base, analyzed phenolic compounds and proteins contents, and identified polar metabolites. Two rooting experiments were carried out with cuttings from rejuvenated and adult mother plants, both collected in the four seasons of the year, submitted to treatments with indole butyric acid (0, 2000, 4000, 6000, and 8000 mg L− 1 IBA), and kept in a greenhouse for 45 days. The experimental design was completely randomized in a double factorial scheme for cutting experiments (5 [IBA] x 4 seasons), and for biochemical analyses (2 mother plants x 4 seasons, material collected in the moment of rooting experiment installation and after 45 days); for metabolomic characterization, the 2 mother plants were evaluated only at summer experiment installation. Propagules from rejuvenated mother plants collected in the spring are more viable and indicated to produce A. brachiata cuttings (25.25% rooting), not requiring the use of IBA. Despite the higher rooting rate of cuttings from rejuvenated mother plants, there are no anatomical differences from adult mother plants cuttings. The highest contents ​​of phenolic compounds were observed in propagules from rejuvenated mother plants in spring, indicating a positive effect of these compounds on the rhizogenic process. Maleic acid, 2-hydroxy-glutaric acid, mannose-6-phosphate, ribonic acid, glycine, and phosphoric acid were found in higher concentrations in cuttings from rejuvenated mother plants, with possible beneficial physiological effects on cuttings rooting.