A procedure for shoot organogenesis in vitro from leaves and nodes of an elite Eucalyptus gunnii clone: comparative histology

• Published in: Plant science (Limerick) 2001-09, Vol.161 (4), p.645-653
• Main Authors: Hervé, Philippe, Jauneau, Alain, Pâques, Marc, Marien, Jean-Noël, Michel Boudet, Alain, Teulières, Chantal
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Economic plant physiology; Eucalyptus; Fundamental and applied biological sciences. Psychology; Histology; In vitro culture; Plant physiology and development; Regeneration; Tissue culture; Tissue cultures, protoplasts; Woody plant
• ISSN: 0168-9452; 1873-2259
• DOI: 10.1016/S0168-9452(01)00451-4

In Eucalyptus, shoot regeneration has mainly been achieved from juvenile material (i.e. seedlings). Here, we present a procedure for shoot regeneration from different organs (leaves, internodes, nodes) of micropropagated E. gunnii clones derived from selected trees using a basal regeneration medium that included 0.04 μM picloram and 2.25 μM N6-benzyladenine (BA). About 10% of the leaves or internodes regenerated an average of four buds after 10–12 weeks of culture and more than 50% of the nodes regenerated an average of 20 buds after 6–8 weeks of culture. Explant browning was reduced by increasing the BA concentration in a two-step procedure. The ability to regenerate buds was strictly correlated with the formation of protuberances of chlorophyll-containing cells from the different organs tested. Node-derived protuberances originated from pre-existing meristematic areas, whereas leaf-derived protuberance formation involved the leafs vascular system. Histological studies revealed that adventitious buds originated from the peripheral layers of both leaf-derived and node-derived protuberances.