Many mycorrhizosphere microorganisms can produce
plant growth regulating compounds in vitro. Plant growth
regulating compounds are known to mediate root growth and
development. In reforestation practices, conifer tree
seedling growth and survival are linked to rapid root
growth and development after outplanting. Multifactorial
experiments were conducted to document variations in
conifer seedling growth, survival and endogenous root
indole acetic acid (IAA) content as influenced by
exogenously applied plant growth regulators and
inoculation with ectomycorrhizal fungi capable of
differential in vitro IAA and ethylene production.
Capacity for in vitro IAA and ethylene production by
mycorrhizal fungal isolates was partially correlated to
levels of endogenous root IAA and root growth in
inoculated seedlings as well as field transplanted
nursery-grown seedlings. Although degree of correlation
usually varied with fungal isolate as well as conifer
species, IAA-mediated changes in root growth and seedling
survival could indirectly be attributed to in vitro fungal
plant growth regulator production capability.
Exogenous application of plant growth regulating
substances at different times during seedling growth and
development resulted in significant changes in growth,
survival and endogenous root IAA content of both
experimental seedlings and field transplanted nursery-grown seedlings. Although effects varied with conifer
species and stock types, IAA mediated increases in root
growth and survival are projected to be cost beneficial.
These results are not only indicative of the
complexity of interactions which can occur between
symbionts in the mycorrhizosphere but also suggest
potential methods for manipulating plant growth regulator
mediation of conifer root growth for practical purposes in
reforestation. / Graduation date: 1994
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/35592 |
| Date | 13 December 1993 |
| Creators | Scagel, Carolyn F. |
| Contributors | Linderman, Robert G. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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