Scientific contribution No. 1143 from the New Hampshire Agricultural Experiment Station.
Response of balsam fir and hemlock roots to injuries
Article first published online: 7 JUN 2007
European Journal of Forest Pathology
Volume 12, Issue 6, pages 357–364, December 1982
How to Cite
Tippett, J. T., Bogle, A. L. and Shigo, A. L. (1982), Response of balsam fir and hemlock roots to injuries. European Journal of Forest Pathology, 12: 357–364. doi: 10.1111/j.1439-0329.1982.tb01289.x
- Issue published online: 7 JUN 2007
- Article first published online: 7 JUN 2007
- Receipt of Ms. 29. 3. 1982
Drill wounds in balsam fir and hemlock roots activated the nonspecific resistance mechanisms of compartmentalization in wood and necrophylactic periderm in bark. Tangential bands of resin ducts localized around the wounds constituted the barrier zones in the secondary xylem of conifer roots. Barrier zones were more extensive in roots which showed symptoms characteristic of invasion by fungi and bacteria after wounding. This observation supports an expanded definition of barrier zones; barrier zones may form not only in response to mechanical wounds but also in response to xylem injury caused by pathogens.
Multiple bands of resin ducts were common in young xylem when bark lesions developed around wounds. Necrophylactic periderms isolared dead bark from living bark. Development of phellem cells with dark contents and thick suberized walls, typical of exophylactic periderm, followed initiation of necrophylactic periderm. The wound responses were similar in both balsam fir and hemlock.