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Sheel Bansal, Connie Harrington,
Peter Gould, J. Bradley St. Clair
Pacific Northwest Research Station
USDA Forest Service
Genotypic and environmental effects on water deficit and water
loss in coastal Douglas-fir(Pseudotsuga menziesii
var. menziesii)
Genetic differentiation
Pseudotsuga menziesii var.
menziesii
Pseudotsuga menziesii var.
glauca
U.S. Geological Survey
http://www.galuzzi.it
Barrie Andrian
Pseudotsuga menziesii var. men
ziesii
Genetic differentiation
CaliforniaOregon
Environmental effects
Same populationTwo environments
Temperature
Copyright © 2014, PRISM Climate Group, Oregon State University, http://prism.oregonstate.edu Map created 5 May 2014
PrecipitationSummerSummer WinterWinter
WA coast
CA inland
Climate is getting warmer and drier
Decrease in June, July and August precipitation
Mote and Salathé. 2009. Future climate in the Pacific Northwest
Key questions
Which populations are most at risk?
Which populations are least at risk?
Key questions
Is there variation in drought-resistance among populations?What are the climate factors associated with drought-resistance?How do environmental conditions interact with genotype to influence drought-resistance?
Hypothesis:Populations from warmer, drier climates will be more drought-resistant that those from cool climates.
Test: Genecology, reciprocal transplant study• Multiple populations at multiple
common gardens
0 1 2 3 4 5 6 7 80
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Aridity
Dro
ught
-res
ista
nce
Warmer, drier source-climateCooler, wetter source-climate
Hypothesis:Populations from warmer, drier climates will be more drought-resistant that those from cool climates.
Test: Genecology, reciprocal transplant study• Multiple populations at multiple common
gardens
0 1 2 3 4 5 6 7 80
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Aridity
Dro
ught
-res
ista
nce Warm conditions
Cool conditions
DF Seed-Source Movement Trial
60 populations9 test sites 5-years
Drought-resistance trial
Doorstop (WA high elevation): coldest, wettest siteMean max T = 16.1° CGrowing season precip = 671 mm
Buckhorn (WA low elevation): intermediate siteMean max T = 18.7° CGrowing season precip = 420 mmStone (OR low elevation): warmest, driest siteMean max T = 24.9° CGrowing season precip = 184 mm
35 populations3 test sites
Drought-resistance traits
8 cm of twig collectedtransport in ziplock bag
Leaf drying curve
Transpirationmin
0 1 2 3 4 5 6 7 8 9 100
0.10.20.30.40.50.60.70.80.91
Days
Wei
ght (
g)Mass loss/time
Seal end of twig with wax
Drought-resistance traits
8 cm of twig collectedtransport in ziplock bagfresh weight and leaf areaWater deficit and Specific leaf area
Place end of twig in waterturgid weightdry weightWater deficit (TW-FW)/(TW-DW)
Specific leaf area leaf area/dry leaf mass
Trait
Source-climate
3 test sites
35 populations
significance
G x E interaction• Only at
warm test site
Genetic effects• Trees from
warmer climates had
< water loss
Environmental effects(phenotypic plasticity)• Trees at warm
site had < water loss (cuticle thickening)
Genetic effectsTrees from cooler climates had lower rates of water loss (cuticle thickening)
Winter-drought• Needle
desiccation and mortality
Auto-correlated traits• Cold-hardiness =
drought-resistanceAuto-correlated
climate• cold winters +
warm summersMultiple climate variables• simple linear
relationships inadequate
Multiple regression• transpirationmin = 0.19 +
0.0067*Tmin + 0.00012*PrecipGS (R2 = 0.66)
Multiple regression• transpirationmin = 0.19 +
0.0067*Tmin
+ 0.00012*PrecipGS (R2 = 0.66)
Transpirationmin
ConclusionPopulations from regions with:
a)cool winters + dry summers >> drought-resistance.
b)dry summers + warm conditions > drought-resistance
c)cool-climate have ‘built-in’ protection against drought
