REGULATION OF ADVENTITIOUS ROOT FORMATION IN MICROCUTTINGS

Current theory on control of adventitious rooting is reviewed.
Techniques are described by which difficult materials can be conditioned in vitro to enhance their capacity to form adventitious roots.
Shoot cultures of apple (Jonathan, Richared) were subcultured (26°C) with BA (10 mgl^-1) under continious illumination (90-100 μE m^-2s^-1). There was a progressive improvement in the rooting of microcuttings with increasing numbers of subcultures.
Freshly cultured materials did not form roots but 95% of Jonathan microcuttings formed roots after the 9th subculture.

Prolonged subculture leads to various morphological, anatomical and physiological changes including (i) progressive reduction in endogenous GA and ABA (ii) reduction in decarboxylation of applied IAA-1-C¹⁴.

Enhancement of adventitious rooting with prolonged subculture under specific environmental conditions occurs also in D’Ente prune and the technique may be applicable to microcuttings of many woody perennials including ornamentals.
The physiology of conditioning is discussed.

Propagation of Ornamental Plants

M. G. Mullins

https://doi.org/10.17660/ActaHortic.1985.166.6