Responsiveness of Melanoxylon brauna to mini-cuttings technique

Abstract

Abstract Melanoxylon brauna is a species native to the Brazilian Atlantic Forest. It has significant ecological and economic value and is at risk of extinction. The usual method for Melanoxylon brauna propagation is by seeds. However, pest attacks and the short viability of its seeds represent a problem for continuous seedlings production. The aim of this study was to evaluate the potential of vegetative propagation of M. brauna through mini-cuttings technique from juvenile shoots obtained from seedlings, evaluating plant growth regulator dosages and types of mini-cuttings. Five concentrations of indole-3-butyric acid (0, 2,000, 4,000, 6,000, and 8000\xa0mg\xa0kg−1) and two types of mini-cuttings (apical stem and leaf) were evaluated, with four replications. After 90 days in greenhouse, percentage of survival and rooting, number of roots, length of the largest root, surface area, volume, roots diameter, dry weight of the root and aerial part, and total dry weight were evaluated. Results indicated that the mini-stumps of the mini-clonal hedge of M. brauna showed low productivity, always with the dominance of one sprout. M. brauna has low ability for vegetative propagation through mini-cuttings technique in a greenhouse with rooted mini-cuttings values of up to 35.0%. Under controlled conditions of humidity and temperature, rooting of apical stem and leaf M. brauna mini-cuttings is possible. However, leaf cuttings did not show shoot emission and aerial part growth during the 90-day period. Application of IBA influences rooting responses and quality of the adventitious root of M. brauna mini-cuttings, with higher means in the concentrations 4,000, 6,000, and 8000\xa0mg\xa0kg−1 applied to the apical mini-cuttings.