We investigated the root endophytic fungi of lupine using
four approaches: (1) occurrence of fungal colonization in field-collected
roots; (2) growth response of L. latifolius to inoculation
with two types of fungi; (3) structure of root colonizations of
Pinus and Lupinus by Phialocephala fortinii, a septate endophytic
fungus of lupine; and (4) comparison root morphology, mycorrhizal
colonization and natural ¹⁵5N-abundance N₂ fixation of three
legumes. In part 1, three species of Lupinus were never observed
to have fungal colonization; nine species were colonized by VA
mycorrhizal fungi; seven species were colonized by fungi with
septate hyphae which often formed intracellular scierotia, here
called septate endophytes. In part 2, shoot weight of 16 week old
L. latifolius seedlings in the greenhouse was significantly
reduced by Glomus spp. in one experiment; p. fortinii significantly
increased nodule weight in one experiment and reduced it in the
other. In part 3, P. fortinii colonized root epidermal and cortical
cells in the root hair zone on ultimate lateral pine roots, as well
as cortical and epidermal cells of primary roots of Pinus and
Lupinus. Fungal colonization was inter- and intracellular with
scierotia forming in cells of both hosts. Labyrinthine tissue, a
type of fungal differentiation which occurs in the Hartig net of
ectomycorrhizae, formed sporadically on pine roots. In part four,
Roots of Lupinus albicaulis cv. hederma had a significantly larger
proportion of coarse roots (> 1 mm diameter) and significantly
less mycorrhizal colonization than two other legumes, Medicago
lupinula and Trifolium hybridum. Estimated aboveground N
derived from fixation ranged from 6.1 to 39.9 kg per hectare
(average = 22.0 kg/ha) and did not vary significantly among
species. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36088 |
| Date | 12 May 1992 |
| Creators | O'Dell, Thomas E. |
| Contributors | Trappe, James M. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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