© 1993 Heron Publishing—Victoria, Canada
In vitro shoot proliferation determined by explant orientation of juvenile and mature Quercus rubra L.
A. M. Vieitez, F. Pintos, M. C. San-José and A. Ballester
Plant Physiology, CSIC, Apartado 122, 15080 Santiago de Compostela, Spain / Received April 1, 1992
Summary
Shoot cultures of Quercus rubra (L.) were established from both juvenile and adult plant material. Initial explants from epicormic shoots formed on the basal
zone of the trunks had a greater capacity for in vitro establishment than explants from crown branches. The growth of vigorous
axillary shoots was obtained by culturing decapitated shoots horizontally on Woody Plant Medium supplemented with 0.2 mg l–1 of 6-benzylaminopurine. After 3 weeks of culture the shoots were transferred to fresh medium for two more weeks, giving a
5-week multiplication cycle. Efficient shoot production was achieved by combining three treatments favoring the growth of
lateral buds: excision of the apex, horizontal culture and cytokinin treatment. The addition of indoleacetic acid or indolebutyric
acid to the multiplication medium did not improve shoot proliferation rates, and naphthaleneacetic acid was detrimental. Recycling
the same explant for several successive subcultures improved the efficiency of the propagation procedure. Using the optimal
multiplication procedures, nine clones (six of juvenile origin and three from adult trees) were tested in vitro and it was
found that genotype and age affected performance.
Keywords:
horizontal shoot culture, micropropagation, propagation coefficients, recycling, red oak, vegetative propagation.
