Mechanisms of accelerated
germination of Astragalus
utahensis with Alternaria and
Aspergillus fungi.
Brad Geary1, Ph.D.; Sean D. Eldredge1; Scott Jensen3, M.S. and John Gardner2 Ph.D.
Plant and Animal Sciences1, Integrative Biology2 , Brigham Young University, Provo, UT;
Shrub Sciences Laboratory3, USDA Forest Service, Provo, UT
Funded by:
US Forest Service
Seed Germination
{
Definition: “…the metabolic awakening of
the latent seed and resumption of
developmental processes.”
Vasquez-Ramos, 2003
{
Primary Step
z
z
Speed in germination allows establishment
Germination in xeric environment Evenari, 1962
optimal moisture
{ fast germination
{ seed bank
{ habitat restriction
{
Astragalus utahensis Utah milkvetch
{
Family:
z
{
Genus:Rios & Waterman, 1997
z
z
z
{
Fabaceae
Wide Distribution
Toxicity
Great Basin & Diversity
Species:Barneby, 1964
z
z
z
z
perennial
non-toxic
herbaceous taproot
xerophyte
Astragalus utahensis-by: Bob Skowron, www.RMRP.com
The Fungi
• Damage encouraging
leaching.
Fu
Ge nga
Un org l ph
ive e B oto
rsi ar s b
ty ron y:
of
,
Gu
elp
h
• AlternariaRotem, 1994
– Ubiquitous
– Parasitic or Saprophytic
– Dematiaceous
hyphomycete
– Optimal growth:
• AspergillusCotty
et al.,
Aspergillus
1994
– Ubiquitous
– Saprophytic
– Aflatoxins
– Wide range of plant
diseases
– Optimal growth:
• Dry, droughty
Findings in the Literature
•25 studies with 35 references
to seed/microbial interactions
Seed-Microbe Study Synopsis
•Fungi dominate these
interactions; 68% (approx. 24
of the 35 references)
•35 references with only 1
linked to beneficial interactions
by the test fungi; 3%.
Passive
Undefined
60%
P ercent Total References
•Beneficial interactions are a
total minority participant; 20%
(only 5 Fungal references;
1 study linked to test fungi)
Active
50%
31.43%
40%
30%
20%
14.29%
22.86%
25.71%
10%
5.71%
0%
B eneficial - 20.00%
Harmful - 54.29%
Interactions
No npro ductive 25.71%
Materials and Methods
{
Confirm response
z Direct Inoculation
{ Scarifiy- 98% H2SO4.
Inoculate with
spore solution.
{ Record
germination.
{
2 test confirmations
st generic-spore
{1
count
{
2nd
precise-spore
count equal to 1.0x106
sprs/mL.
In-Vitro Germination Response
'Fixed Spore Count' Direct Inoculation: Tests 1-3
100%
90%
80%
% germination
70%
60%
A**
50%
ASP
ALT
H20
40%
30%
B*
20%
10%
C*
0%
1
ASP
0
ALT
0
2
3
0.0083 0.0125
0
4
0.025
5
6
7
8
9
10
11
0.0417 0.0708 0.1125 0.1292 0.1583 0.1792 0.1958
0.025 0.0958 0.1333 0.2208 0.2958
0.4
0.4542 0.4875 0.5167
H20 0.0042 0.0083 0.0125 0.0208 0.0333 0.0333 0.0375 0.0417 0.0417 0.0417 0.0417
Time (days)
Time Course Series
Chem TC 1-3 p
1
0.9
0.8
0.7
% germ
0.6
ASP
ALT
0.5
H20
PB
0.4
0.3
A*
0.2
B
B
B
0.1
0
1
2
3
ASP
0
0
0
ALT
0
0
0
H20
0
0
PB
0
0
4
5
6
0.00833 0.02083 0.0375
0
7
8
9
10
11
0.05
0.0875
0.1
0.12917
0.2
0.00833 0.02083 0.03333 0.04167 0.04583 0.09167 0.1125
0.00417 0.0125 0.02083 0.02917 0.0375 0.04583 0.04583 0.04583
0
0.05
0.00417 0.00833 0.02083 0.02917 0.02917 0.04167 0.06667 0.06667
Time (days)
Materials and
Methods
-Scarify: 98% H2SO4, 20 min.
-Flood Inoculate: with
solution @ 1.0X106
spores/mL.
-Plant: Randomized Complete
Block Design.
Greenhouse Trials
Greenhouse Tests 1-3 Day 30
60.00%
Alt
52.59%
50.00%
40.00%
30.00%
Asp
28.89%
20.00%
Cntrl
4.44%
10.00%
0.00%
Treatment
Field Trials
47
BYU
1300 m
2 in
43
Nephi
Fountain
Green
1500 m 1800 m
1.5 in
1 in
40
Materials and Methods
ALMACO equipment
2005 Fall Field Trials
Field Trials @ Nephi F05
%Germination
40.00%
Cntrl
36.13%
35.00%
30.00%
25.00%
20.00%
Field Trials @ Fountain Green F05
% Germination
15.00%
40.00%
10.00%
5.00%
Cntrl 2
4.27%
35.00%
Alt
2.27%
Alt 5
2.00%
Asp
3.73%
Asp 5
2.53%
30.00%
25.00%
0.00%
Treatments
20.00%
15.00%
10.00%
5.00%
Cntrl
8.40%
Cntrl 2
1.07%
Alt
6.00%
Alt 5
5.60%
0.00%
Treatments
Asp
9.73%
Asp 5
8.00%
2006 Field Trials
Field Trials @ Nephi F06
% Germination
40.00%
30.00%
20.00%
Scar
14.80%
Alt
17.33%
Asp
20.67%
Soak
12.13%
Field Trials @ BYU F06
Asp
%Germination
40.00%
10.00%
Unscar
1.20%
0.00%
32.67%
30.00%
Alt
21.07%
Treatment
20.00%
Scar
15.20%
Soak
13.20%
10.00%
Unscar
4.40%
0.00%
Treatment
2007 Field Trials
Field Trials @ Fountain Green S07
% Germination
40.00%
35.00%
30.00%
check scar
25.00%
check soak
20.00%
Alt
15.00%
Asp
10.00%
5.00%
Scar
4.40%
Soak
0.53%
Alt
0.80%
0.00%
Treatment
Asp
1.07%
Unscar
4.67%
unscar
Conclusions
{
{
{
{
Greenhouse tests show a pattern of response
nearly identical to the previously established
in-vitro tests.
Field trials showed variability between sites and
inconsistency in treatment response as compared
with the in-vitro and greenhouse trials.
It is evident from the results that due to
availability of moisture and other factors Fall
plantings supply a greater benefit than Spring
plantings.
It should be noted that the greatest benefit
comes as a result of the greenhouse plantings
and practical application would serve to utilize
treatment as a part of preparing seedlings for
transplant rather than direct seeding in the field.