© 2003 Heron Publishing—Victoria, Canada
Developmental stages during the rooting of in-vitro-cultured Quercus robur shoots from material of juvenile and mature origin
N. Vidal (1), G. Arellano (1, 2), M. C. San-José (1), A. M. Vieitez (1) and A. Ballester (1, 3)
1. Instituto de Investigaciones Agrobiológicas de Galicia, CSIC, Apartado 122, 15080 Santiago de Compostela, Spain / 2. Present address: Especialidad de Fruticultura-IREGEP-Colegio de Postgraduados, Km. 36.5 carretera México-Texcoco, Montecillo
Edo. de México, CP 56230, México / 3. Author to whom correspondence should be addressed (aballester@iiag.cesga.es) / Received March 19, 2003; accepted May 26, 2003; published online November 17, 2003
Summary
In-vitro-cultured shoots of clones initiated from shoots of the basal parts (BS) and the crown (C) of two mature Quercus robur L. trees were subjected to rooting experiments to relate rooting with shoot topophysical origin. The BS shoots exhibited
morphologically juvenile characteristics and rooted more easily after indole-3-butyric acid (IBA) treatment than C shoots.
When naphthylphthalamic acid (NPA) was applied to BS shoots, rooting capacity decreased and root emergence was delayed at
least 2 days compared with shoots treated with IBA only. During the first days of the rooting process, endogenous indole-3-acetic
acid (IAA) concentration was higher in C shoots than in BS shoots, regardless of whether the shoots were treated with NPA.
Mitotic figures were observed in cells from the basal part of both BS and C shoots 24 h after IBA treatment. After 4 days
of IBA treatment, the occurrence of histological events differed between BS shoots and C shoots. Cells of BS shoots became
meristematic, giving rise to meristemoids and root primordia, whereas no differentiation of root meristemoids occurred in
cells of C shoots. Thus, although adult oak material (C shoots) is capable of responding to the initial stimulus of auxin
during the adventitious rooting process, the endogenous IAA concentration is not the factor limiting rooting in adult material.
Keywords:
anatomical study, endogenous auxin content, oak, root primordium formation.
