# Cuttings from adult African mahogany individuals through tissue rejuvenation/reinvigoration

## TL;DR

This study explores how to improve the cloning of adult African mahogany trees by rejuvenating their tissues and using specific biochemical indicators.

## Contribution

The study is the first to investigate cloning adult Khaya genotypes, focusing on rejuvenation and biochemical markers for propagation.

## Key findings

- IBA application had no significant effect on survival or rooting in cuttings from Khaya species.
- Adventitious rooting percentages were below 30%, typical for species with low propagation potential.
- Superoxide dismutase and catalase activities were suggested as indicators of tissue rejuvenation in Khaya species.

## Abstract

Most woody species undergo morphological, physiological, and biochemical changes during ontogenetic development from juvenile to adult phases, especially in terms of clonal potential, growth vigor, and adventitious rooting capacity. This study focused on generating information to support the vegetative propagation of adult individuals of Khaya spp., aiming to optimize the mechanisms involved in the induction of adventitious rooting and its association with indole-3-butyric acid (IBA). The experiment evaluated the rejuvenation/reinvigoration of plant tissues from three Khaya species by comparing juvenile and adult materials, epicormic shoots, and tissues rescued from the base of felled trees. In contrast to most studies, which focus primarily on juvenile materials, this is the first to investigate cloning through the rescue of adult genotypes, targeting the multiplication of individuals expressing superior phenotypic traits in the field. The results indicated that IBA application did not significantly influence survival, rooting, or the occurrence of abnormalities in the cuttings. Although adventitious rooting was achieved for all species, the percentages did not exceed 30%, reflecting typical results for species with low propagation potential. Basal cuttings showed enzymatic activities of superoxide dismutase, catalase, and peroxidase similar to those observed in juvenile materials, although total protein and carbohydrate contents were less significant. Based on these findings, the quantification of superoxide dismutase and catalase is recommended as physiological indicators of rejuvenation for K. grandifoliola, while superoxide dismutase is recommended for K. senegalensis and K. ivorensis. The biochemical differences observed among the materials suggest a strong relationship with the degree of physiological maturation and the expression of antioxidant mechanisms, providing important information for future research into clonal propagation and genetic improvement of Khaya spp. Strategies such as successive propagation cycles of rescued materials may contribute to increased adventitious rooting percentages and, consequently, to the rejuvenation/reinvigoration of tissues.