1993 - Mycological Society of America

Poster C8; Sunday pm
Mycorrhizal colonization of grasses and spore
abundance in semi-arid regions of west ex as
. . and John C. Zak. Ecology Group, Dept.
Shivcham S. Dhllllm
of Biological Sciences, Texas Tech Univ., Lubbock, Texas
79409-3131.
Root colonization of Schizachynum scoparium, Andropoga halli, Spore
bolos nyhndrus, Aristida pu&rea and Erapfis sp; by vesiculararbuscular
mvcorrhizal fund and the abundance of mvcomhizal
spores in CR6 (~onservatioi Reserve Program) grassland and sandshinnery
oak (Quercus haomdifl communities were examined for one
year. VAM fungal sporulation in both communities showed similar
seasonal patterns, although abundance of spores in CRP soil was
higher than that on sand-shinnery oak site. Colonization levels were
significantly higher in the roots of S. scoparium, A. halli and S. cryptandrus,
than in A. purpuren and Eragrosfis sp. on both sites. Seasonal
pattern in colonization varied according to species and were essentially
similar for each species in both sites. Mycorrhizal inoculum
potential varied according to species and site. The results suggest that
within a semi-arid region different species of grasses and VAM fungi
may show similar seasonal patterns, although colonization levels of
individual species and abundance of spores of VAM species can vary.
Mycorrhizal inoculum potential data suggest that CRP site is a higher
inoculum source than the native sand shinnery oak site.
Aquatic fungi associated with
West Virginia mountain streams
Tuesday, 4:s pm
Tara Dubev, Steven L. Stephenson, and Pamela J. Edwards.
Dept. of Biology, West Virginia Institute of Technology,
Montgomery, WV 25136; Dept. of Biology, Fairmont State
College, Fainnont, WV 26554; and USDA Forest Service,
Timber and Watershed Laboratory, Parsons, WV 26287.
The distribution pattern of the aquatic fungi occurring in six streams
located on or near the Femow Experimental Forest in Tucker County,
West Virginia, were studied d d g the 1991 and 1992 field seasons.
Water pH averad >5.5 in three of the streams, whereas the others
were relatively more acidic (average pH = 4.2,3.9 and 3.2, respectively).
Sampling methods used induded (1) isolating conidia from stream
water by me-= of a membrane filtration techniqie, (2) placing litter
bags prepared with leaves from four different tree species in the
streams for periods ranging from 14 to 112 days, and (3) "baiting" the
streams with various types of organic material. The mycoflora of the
streams we sampled indudes at least 142 taxa (44 chytridiaceous fungi
and water molds, 49 non-Ingoldian hyphomycetes, and 49 Ingoldian
hyphomycetes). The total numbee total number (27 taxa) of chytridiaceous
fungi and water molds present in the stream with the highest
pH (7.9) was appreciably higher than the numbers (15-18 taxa)
recorded for the other streams. The general pattern for aquatic hyphomycetes,
based on the presence of conidia filtered from water samples,
was for the number of taxa to decrease with decreasing pH, whereas
the lowest numbers of conidia per 1000 ml of water were recorded at
the two extremes of the pH gradient. Red oak (Quercus rubra) litter was
colonized by an average of 14.6 taxa of aquatic hyphomycetes in the six
streams, sugar maple (Am saccharurn) litter by 12.6 taxa, and mixed
red maple (A. rubrum) and beech (Fagus grandifilia) litter by 10.6 taxa.
For all three types of litter, numbers were generally high& for the less
acidic streams and lower for the more acidic streams. (Supported - - in
part by funds provided by the USDA Forest Service.)
Wednesday, 9:OO am
The possible effects of Diflubenzuron on
the growth, sporulation, and enzymatic
activities of aquatic hyphomycetes
Tara Dubey, Steven L. Stephenson, and Pamela J. Edwards.
Dept. of Biology, West Virginia Institute of Technology,
Montgomery, WV 25136; Dept. of Biology, Fairmont State
College, Fairmont, WV 26554; and USDA Forest Service,
Timber and Watershed Laboratory, Parsons, WV 26287.
The possible effects of Diflu-n (DFB) on the growth, sporulation,
and leaf litter colonization of aquatic hyphomycetes under
natural conditions were studied by (1) isolating conidia from samples
of stream water by means of a membrane filtration technique and (2)
direct microscopic and (2) direct microscopic examination of the fungi
cole nizing litter bags containing leaves of red oak (Quercus rubra) and
sugar maple (Am sacdrmum) placed in two treated and two control
watersheds of the Femow Experimental Forest prior to the application
of this chemical insecticide. In addition, mycelial mowth and cellulase
enzyme activity of six species of hyphomycetes isolated from the
watersheds were studied in the laboratory. Cellulase enzyme activity
was assessed using a depth of clearance @C) test and spectrophotometric
analysis of the reducing sugars produced as a result of exoglucanase
and endoglucanase activities. Appreciable increases in (1) the
numbers of conidia filtered from water samples and (2) the extent of
colonization of litter bags were noted two days after application of
DFB to the treated watersheds. The tolerance of aquatic hyphomycetes
to different concentrations of DFB varied among the species tested, but
DC was maximum at 5 ppm for five of the six species tested. In liquid
culture an increase in endoglucanase activity at 20 ppm of DFEI was
noted for four of the six species, whereas three species displayed a
decrease in ex~~lucanaseactivity in the presence of DFEI. (Supported in
part by funds provided by the USDA Forest Senrice.)
Wednesday, 1030 am
Unusual fungi isolated from cherry fruits
Frank M. Dusn and Rodney G. Roberts. USDA, ARS, Tree ,
Fruit Research Laboratory, 1104 N. Western Ave., Wenatchee,
WA 98801.
Fruits of Pnmus aoium L. cv. 'Bing' were surface disinfested and incu-
bated for recovery of potentially pathogenic fungi. A small number of
isolates were provisionally classified as Leptodiscelln africana, Cladospaspa-
urn pomphorum and Sporonnia subticinensis. These fungi are seldom
reported and not previously isolated from cherry; C. porophorum
demonstrated pathogenicity to fruit. Other unusual isolates were
assigned to Phaeolamukrrin and Mycmllosielh. The Phaeormnulnria dif-
fered from P. hachijoensis chiefly in the relative proportions of septate
and nonseptate conidia.
Tuesday, 10:15 am
Adhesives in fungi: the adhesive lcnob
of capilliconidia of Basidiobolus ranarum
exhibits unique ultrastructural features
-. College of Veterinary Medicine, North
Carolina State Univ., Raleigh, NC 27606.
Adhesives are of major importance to fungi for dispersal purposes as
well as attachment to potential substrates prior to penetration. Nematode-trapping
fungi capture prey with adhesives, plant pathogens
produce materials to attach to host surfaces prior to penetration, and
~pkaerobolus produces adhesive materials atthe surfice of the glebal
mass, allowing it to attach to potential substrates following discharge.
The capilliconidia of Basidiobolus rrmmum produce an apical droplet of