Rooting of stem cuttings of Eucalyptus: A rooting inhibitor in adult tissue

Abstract

The available physiological evidence suggests that ontogenetic ageing of E. Grandis seedlings involves a direct and quantitative association between decreased rooting ability of stem cuttings and increased levels of a rooting inhibitor in the tissue forming the base of the cutting. As detected by bioassay, this inhibitor is present only in adult tissue, which very rarely forms roots from stem cuttings. It is absent in easily rooted seedling stems of all Eucalyptus species tested, but it is also absent in the easily rooted adult tissue of the exceptional species E. deglupta. The ability of seedling cuttings of E. deglupta to root very easily in water provides an appropriate bioassay for monitoring the presence of inhibitor in other Eucalyptus species.

Cutting propagation of Quercus acutissima clones after rejuvenation through serial grafting

“…Doorenbos (1954) and Paton et al (1970) also reported similar results using ivy and eucalypts, respectively. Moon et al (1988) reported successful rooting from almost all the ramets of Q acutissima obtained from the second grafts of the 2-year-old rootstocks.…”

Flavonoid Accumulation Is Correlated with Adventitious Roots Formation in Eucalyptus gunnii Hook Micropropagated through Axillary Bud Stimulation

“…However, perhaps under the growth conditions used by these authors endogenous flavonoids rapidly accumulated to toxic levels. In addition, the age of the explants used might have had an influence on rooting ability (22). In our work, the enhanced flavonoid accumulation appeared beneficial for the explants.…”

“…In fact, this capability which is typical for the cuttings taken from Eucalyptus seedlings disappears when the plants, still in juvenile phase, become 12 to 14 months old (6,10,13). Other physiological changes may occur (6,24) that parallel the loss of the ability to form adventitious roots; for example, the accumulation of some phenolic substances was found to be correlated with the loss ofrooting ability in Eucalyptus grandis cuttings (22). However, data concerning in vitro culture are not available.…”

Tissue Culture of Corymbia and Eucalyptus

“…Plantation trees generally display higher adventitious rooting capacity, stem growth, internode length, and developmental commitment to vegetative growth when they are propagated from juvenile, rather than mature, explants or cuttings [54,55,61,62,183,184]. However, many eucalypt species progress through some of these juvenile-to-mature phase transitions at a very young age and low canopy height [11,39,40,44,63,64,67,185]. This may be the one of the reasons why seeds (or in vitro seedlings) have been the initial explant source in 54% of the eucalypt tissue-culture techniques in which an explant source has been stated (Table A1).…”

“…The proliferation capacity of shoot tips, nodes, or axillary buds and the subsequent growth of their plantlets may also be influenced strongly by the position of the tree from which the explant was harvested. Maturation effects such as reduced rooting capacity, shorter internode length, and decreased stem growth [54,55,[59][60][61][62] can become evident from very early stages (i.e., from relatively low explant positions) during the development of eucalypt trees [44,[63][64][65][66][67].…”