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the presentation deals with the response of plants to drought at various time scales
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Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Short and long term Short and long term impacts of water deficits impacts of water deficits
and droughts on and droughts on perennial grasses in perennial grasses in
grasslandsgrasslands
Jean-Louis DurandJean-Louis Durand
Marc GhesquièreMarc Ghesquière
Jean-Paul SampouxJean-Paul Sampoux
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Grasslands: Grasslands: a key for C global cycle 13 January 2010 – FAO Properly managed grasslands – even more than forests – could fight fight
climate change by absorbing and storing carbon dioxide,climate change by absorbing and storing carbon dioxide, according to a newly released report by the United Nations Food and Agriculture Organization (FAO).
The world’s nearly 3.4 billion hectares of grasslands store 30 per cent of store 30 per cent of global soil carbonglobal soil carbon in addition to the substantial amount of above-ground carbon held in trees, bushes, shrubs and grasses. They also account for 70 per cent of agricultural land.
In its report “Review of Evidence on Drylands Pastoral Systems and Climate Change,” FAO noted that grasslands could play a major role in supporting the adaptation and reducing the vulnerability to climate supporting the adaptation and reducing the vulnerability to climate change for the more than one billionchange for the more than one billion people who depend on livestock for a living.
The report also noted that grasslands help improve the soil’s water improve the soil’s water retention capacityretention capacity and thus can help its ability to withstand drought, and help safeguard biodiversity.
In addition, it cautioned that grasslands are particularly sensitivegrasslands are particularly sensitive to land degradation, which affects some 70 per cent of pastures as a result of overgrazing, salinization, acidification and other processes. Pressure on the land is also due to the need to meet fast-growing demand for meat and dairy products.
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Projection of 2 French meteorological Projection of 2 French meteorological models for annual rainfalls in Amodels for annual rainfalls in A22 scenario scenario
(2000-2100)(2000-2100)
Livre blanc Escrime ed. 2009
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Plant and population responses to Plant and population responses to drought or water deficitsdrought or water deficits
1.1. The plant (plasticity)The plant (plasticity)
2.2. The sward (from plasticity to The sward (from plasticity to evolution)evolution)
3.3. The community (from population The community (from population dynamics to speciation)dynamics to speciation)
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
1. The plant response to water deficits1. The plant response to water deficits
Potential volume growth rate * carbon costs (g mm-3d-1)
Roots Leavesstems
Absorbed PAR
LAI
Carbon demand
Partitioning according to environmentally
dependant hierarchy.
Photosynthesis-
Respiration
Carbon Carbon supplysupply
MORPHOGENESIS ENERGY ASSIMILATIONgenotype,genotype,
waterwater
genotype,genotype,waterwater
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Adaptive responses to insure survival and competitionAdaptive responses to insure survival and competition
Leaf area
morphogenesis
Rooting depth
Plant water status
TA
MAXIMISE
MAXIMISE
MAXIMISE
MINIMISE
Trade off
ENERGYENERGY
WATERWATER
1. The plant response to water deficits1. The plant response to water deficits
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Expansion of leaf area Expansion of leaf area Expansion of roots.Expansion of roots. Anticipation - > Anticipation - >
• phenology, phenology, • stomatal conductance ?stomatal conductance ?
1. The plant response to water deficits1. The plant response to water deficits
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Festuca arundinaceaFestuca arundinacea
-.8 -0.6 -0.4 -0.2 0
Mean d (MPa)
0
0.2
0.4
0.6
0.8
1
LE
R re
lativ
e to
co
ntro
l (irrigate
d)
b
-0.8 -0.6 -0.4 -0.2 0
Mean d (MPa)
0
0.2
0.4
0.6
0.8
1.0
LE
R re
lativ
e to
irrigate
d c
on
trol
a
D’après Durand et al. 1997
Lolium perenneLolium perenne
1. The plant response to water deficits1. The plant response to water deficits
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Sensitivity of Sensitivity of tissue tissue expansionexpansion
1. The plant response to water deficits1. The plant response to water deficits
Spollen et al. 1993
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
0 10 % 20 % 30 %Percentage of water consumption
180
150
120
90
60
30
0
Dep
th (
in c
m)
L. multiflorum: 19 mm L4F4: 35 mm
F. a. ssp. glauscescens: 45 mm
DURAND J.L., & al 1997 Eur. J. Agronomy 7: 99-107.
Depth of water extraction, as a quantitative trait
Lm
LmFg (4x)
Fg
1. The plant response to water deficits1. The plant response to water deficits
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
gS
T A
0SdGTA
d
1. The plant response to water deficits1. The plant response to water deficits
Transpiration use efficiency as an integrated estimate of water status and resource acquisition
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Three levels of changesThree levels of changes
1.1. The plant (plasticity)The plant (plasticity)
2.2. The sward (from plasticity to The sward (from plasticity to evolution)evolution)
3.3. The community (from population The community (from population dynamics to speciation)dynamics to speciation)
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
How do populations change under How do populations change under dry conditions on the longer term?dry conditions on the longer term?
Under high competition, high water and nitrogen status, the frequency of individuals exhibiting vegetative growth is enhanced in a plot sawn 20 years before.
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
The The EFESTEFEST design (Genetic design (Genetic EEvolution of volution of FestFestulolium ulolium populations under summer water deficit)populations under summer water deficit)
March 2005 June 2006 Sept. 2006 June 2007
Sowing Seed harvest Plant sampling Seed harvest
rain fed
rain fed
4x- BC1 pop.
Amphi. pop.
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Delta Delta 1818O soil water profiles in the O soil water profiles in the spaced-plant spaced-plant trial trial for clonal assessment (sampled for clonal assessment (sampled vsvs initial initial
plants)plants)
soil water 18O (o/oo)
-8 -6 -4 -2 0 2
So
il de
pth
(cm
)
-100
-80
-60
-40
-20
0
d1 vs profondeur d2 vs profondeur d3 vs profondeur
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
population
Lm LmFg INITIAL LmFG FINAL Fg
Me
an
18 O
of
stu
bb
le w
ate
r (o / oo)
-5,5
-5,0
-4,5
-4,0
-3,5
-3,0
1818O plant water in O plant water in spaced-plant trialspaced-plant trial with response of with response of plants sampled in sward compared to the initial seed plants sampled in sward compared to the initial seed
batch of the batch of the FestuloliumFestulolium population population
Lolium FestucaInitial Sampled
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Estimation of plant selection within the Estimation of plant selection within the FestuloliumFestulolium population in sward because population in sward because
of droughtof drought
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0 -0.6 -1.2 -1.8 -2.4 -3 -3.6 -4.2 -4.8 -5.4 -6
Delta O18 in sward 2006
plants sam pled in thedroughted sward
hypotheticaldis tribution at sowing
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0 -0.6 -1.2 -1.8 -2.4 -3 -3.6 -4.2 -4.8 -5.4 -6
Delta O18 in nursery 2008
plants from the initial seed batchplants sam pled in the droughted sward
δ18O in the plants sampled in the rain fed sward has shifted by 0.4 phenotypic standard deviation of the initial population as if 10 % of the least deeply rooted plants (δ18O > - 0.10 o/oo) disappeared because of drought
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Three levels of changesThree levels of changes
1.1. The plant (plasticity)The plant (plasticity)
2.2. The sward (from plasticity to The sward (from plasticity to evolution)evolution)
3.3. The community (from population The community (from population dynamics to speciation)dynamics to speciation)
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
3. Long term evolution and speciation3. Long term evolution and speciation
Biogeography of water deficit tolerance: fine-Biogeography of water deficit tolerance: fine-leaved fescues leaved fescues
Sampoux and Huyghe 2010
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Festuca nigrescens
Festuca rubra ssp fallax
Festuca ovina
3. Long term evolution and speciation3. Long term evolution and speciation
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Modelled ecological probability of presence of Festuca nigrescens (Sampoux and Badeau, 2009)
3. Long term evolution and speciation3. Long term evolution and speciation
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Conclusions / 1Conclusions / 1 Fast responses of plants to water deficit: some Fast responses of plants to water deficit: some
adaptive, most of them mere passive reactions to adaptive, most of them mere passive reactions to low water supply. low water supply.
Plant structures produced Plant structures produced previousprevious to drought to drought and mantained ability of plants and mantained ability of plants following following drought drought are importantare important
Drought is hence a selection pressure at the scale Drought is hence a selection pressure at the scale of the sward. of the sward.
Dense canopies and competition for water and Dense canopies and competition for water and light need be considered together.light need be considered together.
Adaptation to drought tolerance seems to drive Adaptation to drought tolerance seems to drive spatial distribution of tightly related (fine-leaved) spatial distribution of tightly related (fine-leaved) fescue speciesfescue species
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Conclusions: / questions Conclusions: / questions
What are the adaptative characters involved in What are the adaptative characters involved in drought survival in closely related grass drought survival in closely related grass populations ?populations ?• Depth of rooting ?Depth of rooting ?• Transpiration use efficiency ?Transpiration use efficiency ?• Nitrogen status ?Nitrogen status ?• Morphogenesis ?Morphogenesis ?• Phenology ?Phenology ?
How closely linked are the various traits ?How closely linked are the various traits ?
Adaptation of perennial plants to episodic Adaptation of perennial plants to episodic drought: impact on ecosystems 6-8 Oktobdrought: impact on ecosystems 6-8 Oktober 2010er 2010
Thank you for your attention