© 1988 Heron Publishing—Victoria, Canada
Root growth in Sitka spruce and Douglas-fir transplants: dependence on the shoot and stored carbohydrates
J. J. Philipson
Forestry Commission, Northern Research Station, Roslin, Midlothian EH25 9SY Scotland / Received November 19, 1987
Summary
When dormant Sitka spruce (Picea sitchensis (Bong.) Carr.) transplants were lifted from the nursery in March and transferred to favorable growing conditions in a controlled
environment chamber, new roots emerged and elongated even when the plants were bark-ringed so that the roots could not receive
metabolites from the shoot by phloem translocation. Carbohydrate analysis showed that starch reserves in the roots of the
bark-ringed plants were depleted, indicating that these reserves provided the energy source for new root growth. The shoot
also had a role in new root growth as excised root systems showed greatly reduced root growth. This response is compared to
that of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in which bark-ringing prevented root growth indicating that current photosynthate is needed for new root
growth. The findings are discussed in relation to the problems of establishing these species in forest plantations.
