Mini-cutting condition on the identification of rooting-biomarkers in easy- and a hard-to-root Ilex paraguariensis clones.

Abstract

Main conclusion: The mini-cutting physiological condition is vital for the rooting process. For accurate interpretation, considering all mini-cutting responses in an experiment is necessary to identify significant rooting-biomarkers. The study investigates rooting-biomarkers during vegetative propagation, focusing on Ilex paraguariensis (yerba mate) clones of contrasting mini-cutting rooting performance as a case study (i.e., hard vs. easy). To this end, leaf samples were collected at the time of the rooting experiment and stored in an ultrafreezer. After 120 days, five rooted and five dead cuttings from each clone were selected, and their previously-stored leaves were used for metabolite analysis. Utilizing gas chromatography-mass spectrometry analysis, we identified factors influencing rooting processes, stressing the significance of evaluating both rooted and dead mini-cutting for accurate interpretation. The analysis uncovers 86 compounds, being 47 metabolites identified in the leaves, including vital metabolites such as myo-inositol, sucrose, and 6-kestose, displaying varying concentrations among different clones and their responses. The research underscores the importance of assessing the mini-cutting response to prevent misinterpretations. This was evident in the study, particularly concerning variables like myo-inositol in both clones and chlorogenic acids and 6-kestose in the hard-to-root clone. In summary, the findings highlight the critical role of mini-cutting physiological conditions in the rooting process, providing valuable insights to enhance our understanding of plant propagation techniques.