Post print of: Shepherd, M, Rose, TJ & Raymond, CA 2013, 'Rejuvenation of mature native tea tree (Melaleuca alternifolia (Maiden & Betche) Cheel) for vegetative propagation', Propagation of Ornamental Plants, vol. 13, no. 3, pp. 103-111.
Many situations arise in horticulture where it is desirable to vegetatively propagate mature specimens of woody species. Circumventing maturation effects often necessitates rejuvenation following decapitation or wounding but severe treatments may unacceptably modify plant form or endanger survival of individuals of high intrinsic value. This study quantified the maturation effect on strike rates for rooted cuttings and compared mild rejuvenation techniques for Melaleuca alternifolia. Paired samples of juvenile and mature foliage were obtained from most trees (37 out of 40) from one of four native stands. Juvenile foliage was sourced from epicormic shoots that were artificially induced or stimulated by natural stresses. Most trees could be cultured, with 33 out of 40 genotypes captured by vegetative propagation. Roots were first detected on cuttings around 41 days post-setting and rates continued to increase to at least 69 days post-setting. Cuttings derived from epicormic shoots rooted at significantly higher rates under a range of propagation conditions (rooting percentage for epicormic shoots over three experiments; 26.1 ± 3.4%, range 12-42%; for mature shoots 11.2 ± 1.9%, range 6-20%), and those originating closer to the plant base rooted more frequently. Relative to the large tissue-type effect, differences in stock-plant age and site conditions were small and non-significant, as were the differences between stands from the same region. The highest strike rates were obtained by inducing epicormic shoots late in winter, harvesting shoots in mid-summer, and setting cuttings (with 3 g l-1 IBA treatment) under a misting system with > 97% humidity and bottom heating of 20ºC.