Differentiation of Callus and Root Initiation in Pinus banksiana Seedling Cuttings
File(s)
Date
1981-01Author
Montain, Cheryl R.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
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Show full item recordAbstract
Jack pine (Pinus banksiana Lamb.) is an important
forest species in the Lake States Region and across
Canada to the Rocky Mountains. Jack pine can maintain
itself on unproductive, dry, nutrient poor soils. Opportunities
for genetic improvement within the species are numerous as wide variations are found in vigor, wood and
cone characteristics, stem and crown form, and insect
and disease resistance.
Vegetative propagation is an important tool used in
stock improvement. Through vegetative propagation genetically
superior stock may be introduced quickly into tree
improvement programs.
Some tree taxa, for example Salix and Populus,
root quite easily because they contain preformed root
initials (Carlson, 1938). However, latent root initials
have not been described for any of the conifers commonly
used in forestry (Dalgas, 1973). In these hard-to-root
species, root initiation has been found in callus (Satoo,
1955), a tissue composed of large thin-walled cells developing
as a result of injury (Esau, 1977).
An accurate understanding of the processes and factors
affecting root initiation in cuttings of Pinus
species is lacking. Nienstadt et al. (1958) say,
"The mysteries of root initiation (in cuttings)
remain mostly unsolved . . . We are aware of the
important environmental factors governing rooting
but we know extremely little of the internal
mechanisms controlling root initiation . . ."
I have attempted to study the development of callus
on seedling cuttings of Pinus banksiana and the development
of roots and associated anatomical features in
that callus. Material for this study, supplied by Dr.
Bruce Haissig, plant physiologist, at the U.S. Forest
Service Forestry Sciences Laboratory in Rhinelander,
Wisconsin, was control (untreated) material from a physiology
study of effects of different growth substances
on root initiation.