corcobado

Transcription

corcobado

Vzdělávací materiál projektu
Indikátory vitality dřevin
(INVID)
Tento projekt je spolufinancován Evropským sociálním fondem a Státním rozpočtem ČR INVID – CZ.1.07/2.3.00/20.0265
THE ROLE OF Phytophthora
cinnamomi Rands
Rands,, MEDIATED BY SOIL
PROPERTIES AND ECTOMYCORRHIZAE, IN Quercus
ilex L. DECLINE
Tamara Corcobado Sánchez
Federal Research Centre for Forests, Natural
Hazards and Landscape (BFW), SeckendorffGudent-Weg 8, 1130 Vienna, Austria.
G
General
l
Introduction
GENERAL INTRODUCTION
Quercus ilex decline
Holm oak (Quercus ilex L.) decline among other Quercus
At the end of 80, 90
-Delatour,1986.
Delatour 1986 Le problème de Phytophthora cinnamomi sur le chêne rouge (Quercus rubra).
rubra)
-Robin et al., 1998. First record of Phytophthora cinnamomi on cork and holm oaks in France
and evidence of pathogenicity.
-Hansen & Delatour,1999.
Delatour 1999 Phytophthora species in oak forests of north-east France.
France
-Ragazzi et al., 1989. The oak decline: a new problem in Italy.
-Ragazzi
Ragazzi et al., 2000. Decline of oak species in Italy.
-Brasier 1992b. Oak tree mortality in Iberia.
y p
cinnamomi involvement in Iberian oak
-Brasier et al.,, 1993. Evidence for Phytophthora
decline.
-Brasier, 1996. Phytophthora cinnamomi and oak decline in southern Europe. Environmental
constraints including climate change.
-Tuset et al.,1996. Implicación de Phytophthora cinnamomi Rands en la enfermedad de la "seca“
de encinas y alcornoques.
-Gallego et al., 1999. Etiology of oak decline in Spain.
-Sánchez et al., 2000. El decaimiento y muerte de encinas en tres dehesas de la provincia de
Huelva.
2
-Delatour,1986.
rubra)
France
-Ragazzi
y p
decline.
Huelva.
2
-Delatour,1986.
rubra)
France
-Ragazzi
y p
decline.
Huelva.
2
ROOT ROT
CROWN
BRANCH
LEAFCANKERS
YELLOWING
DEFOLIATION
DIEBACK
MYCORRHIZAL REDUCTION
3
Servicio de Protección del
Medio Natural (Romeralo,
2008; Solla et al., 2011, datA
no pub.):
b ) Phytophthora
Ph
hh
spp.
University of Extremadura, La
Orden Research Centre,
Iprocor Gobex (RodríguezIprocor,
(Rodríguez
Molina et al., 2002,2005; del
Pozo, 2006; Solla et al., 2009;
Cardillo et al.,
al 2012):
Phytophthora cinnamomi/
Links with soil, lithological and
climatic factors.
factors ¿¿¿How do
they influence??
Agroforestry Institute (PérezSierra et al., 2013):
Phytophthora spp.
University of Huelva, University of Córdoba
(Grupo de investigación ETSIAM) (Navarro
et al., 2004; Tapias et al., 2005; Sánchez et al.,
2006): Phytophthora
cinnamomi/drough/decline model
4
PHYTOPHTHORA Genus
OOMYCETES Class
STRAMENOPILA Kingdom
*
Oogonium and antheridium
Oospore
Chlamydospore
SEXUAL
*
ASEXUAL
Encystment
Root
LIFE CYCLE
P. cinnamomi
Sporangium
Zoospore
Z
Zoospores
release
l
Cytoplasmic division
* In: Michale Crone (2012)
5
GENERAL INTRODUCTION.
Drought Soil compaction
Growth and root
expansion
Factors influencing Q. ilex
decline
Shallow soil
Hydromorphic
soil
Root access to water
table
Anoxia
Infiltration rate
Mechanical damage
Root rot/Root
elongation
Water
at in gaps of
o
difficult access
Waterlogging/water
deficit
Orography Management Xylophage.
fungi,
bacteria
Water
availability
Shrub layer
Fertilization/cattle
Mechanical
work/motor
vehicle/cattle
Resprouting
removal/excessive
pruning
Recruitment
6
Factors influencing
Phytophthora cinnamomi
Soil water
content
Orography (slope
vs. stream bank)
FFungii
Bacterias
Mycorrhizae
pH
-Fertility
-Organic
matter
-Nitrogen
Phytophthora cinnamomi-Q. ilex
decline relation
Q ilex
Q.
FACTORS AFFECTING THE INTERACTION
P. cinnamomi
● WATER CONDITIONS
Optimal
Waterlogging
Water deficit
W t l
Waterlogging
i  Water
W t deficit
d fi it
● OROGRAPHY
Slope/Stream bank
● SOIL TEXTURE
Fine/Coarse
8
Phytophthora cinnamomi-Q. ilex
decline relation
Q ilex
Q.
FACTORS AFECCTING THE INTERACTION
● OTHER ORGANISMS
P. cinnamomi
OTHER Phytophthoras/Pythium
Nutrients, water
Mycorrhizae
Lack of mycorrizal
association
ECTOMYCORRHIZAE
C b h d
Carbohydrates
Tree vigour
g
Defense
Root destruction, carbohydrate
reduction
9
P. cinnamomi
infection and
decline relation
Section I, IV and V
Relationship
ectomycorrhizal
abundance and
decline
Section II and III
Relationship
ectomycorrhizal
abundance and P.
cinnamomi infection
Section II and III
IInfluence
fl
off soil
il
properties in the
relationship decline/
P. cinnamomi
S ti I and
Section
d IV
Relationship decline
and soil properties
Section I and IV
N-NO3Relationship
P. cinnamomi
i f ti and
infection
d soil
il
properties
Section I and IV
Soil water
table
Redox
potential
N-NH4+
Density
Soil
water
content
Texture
pH
horAh depth
10
OBJETIVES
• ANALIZE THE ROLE OF Phytophthora cinnamomi AS BIOTIC AGENT CAUSING HOLM OAK
DECLINE.
• STUDY THE INFLUENCE OF SOIL WATER CONTENT,
CONTENT SOIL WATER TABLE,
TABLE PHYSICAL AND
CHEMICAL SOIL PROPERTIES IN THE DECLINE OF HOLM OAK AND Phytophthora cinnamomi
INFECTION PROCESS.
• ANALIZE THE ECTOMYCORRHIZAL ABUNDANCE AND DIVERSITY AND ITS RELATIONSHIP
WITH P. cinnamomi presence and Quercus ilex decline.
• ESTUDY HOLM OAK SUSCEPTIBILITY TO P. cinnamomi AFTER EXTREME CLIMATIC EVENTS.
11
Section 1
Combined effects of
soil properties and
Phytophthora
cinnamomi infections
on Quercus ilex decline
Corcobado et al. (2013) Plant & Soil
(i) are the mortality and health status of Q. ilex
trees related to soil pproperties?
p
(ii) do P. cinnamomi infections vary
with soil properties?
(iii) do soil properties interact
with P. cinnamomi by modulating the intensity of
oakk decline?
d l ?
Section I. Combined effects of soil properties and infections
Materials & Methods
● STUDY SITE: 96 STANDS (EXTREMADURA)
Texture
Orography
COARSE
FINE
SLOPE
24
24
STREAM BANK
24
24
● HEALTH STATUS (3 holm oak with DECLINING
SYMPTOMS y 3 holm oaks WITHOUT DECLINING
SYMPTOMS)
● STAND MORTALITY & DECLINE INTENSITY
● PARAMETERS:
Soil depth
P. cinnamomi isolation
horAh depth,
Redox potential
[N-NH4+]
Texture, pH
Soil density
[N-NO3-]
13
SECTION I. Combined effects of soil properties and infections
Results & Discussion
(i) are the mortality and health status of Q.
Q ilex trees related to soil properties?
AT STAND LEVEL
AT TREE LEVEL
STEPWISE MULTIPLE REGRESSION
TWO-WAY ANOVA
Mortality
p-value
Soil density
Declining/Non
declining (health
status)
r2
p-value
l
p<0.001
r2 = 0.138
N-NO3-/N-NH4+ Ratio
Clay at 1,5 m
p = 0.010
p = 0.039
r2 = 0.220
MANOVA
Declining/Non
declining (health
status)
p value
p-value
Redox potential
p = 0.036
14
(ii) do P. cinnamomi
do P cinnamomi infections vary
infections vary with soil properties?
?
AT STAND LEVEL
NON-METRIC
NON
METRIC MULTIDIMENSIONAL SCALING (NMDS) y MULTIRESPONSE
PERMUTATION PROCEDURE (MRPP)
p = 0.020
p = 0.047
15
(ii) do P. cinnamomi
do P cinnamomi infections vary
infections vary with soil properties?
AT TREE LEVEL
MANOVA
TWO-WAYS ANOVA
Soil bulk density
Soil depth
Ah horizon depth
Infected/Not
infected
Infected/Not
infected
p-value
p-value
p = 0.041
Sand percentage
p = 0.046
p = 0.002
y Sand ratio
Clay/
p = 0.054
p = 0.071
16
AT STAND LEVEL
AT TREE LEVEL
TWO-WAYS ANOVA
PEARSON Chi
CUADRADO
Infected/Not
infected
Infected/Not
infected
p-value
p-value
Mortality
p = 0.006
0 006
Decline Intensity
p = 0.003
Declining/Non declining
((health status))
p = 0.006
17
(iii) do soil properties interact with P. cinnamomi
do soil properties interact with P cinnamomi by modulating the intensity of oak
by modulating the intensity of oak decline?
AT STAND LEVEL
Infected/Not
infected
ANCOVA
p-value
Mortality
p = 0.011
0 011
AT TREE LEVEL
THREE-WAYS ANOVA
(b)
70
N declining
Non
d li i (○)
D li i (●)
Declining
p = 0.016
60
% Clay
50
Hor Ah
depth
*
***
40
30
20
10
0
Non-infected trees
P. cinnamomi infected trees
18
Section 2
Ectomycorrhizal
E
h l
symbiosis
y
in decliningg
and non-declining
Q
Quercus
ilex
il trees
t
infected or not with
Phytophthora
cinnamomi
(Forest Ecology and Management, 2014)
(i) Does the relative abundance of
ectomycorrhizal
y
tips
p differ between non-decliningg
and declining trees and between P. cinnamomiinfected and non-infected trees?
(ii) Does the ectomycorrhizal community
depends on the soil properties?
((iii)) D
Do the
h relations
l
bbetween soill properties and
d
ectomycorrhizal abundance vary depending on
whether Q. ile x trees are declined, infected or
f
free
off infection?
i f ti ?
SECTION 2. Ectomycorrhizal symbiosis
Materials & Methods
● SITE STUDY: 96 STANDS (EXTREMADURA)
Texture
O
Orography
h
COARSE
FINE
SLOPE
24
24
STREAM BANK
24
24
● HEALTH STATUS (3 holm oak with DECLINING SYMPTOMS
y 3 holm oaks WITHOUT DECLINING SYMPTOMS)
● PARAMETERS:
Soil depth
horAh depth, redox
potential, root abundance
[N-NH4+]
Texture, pH
Soil bulk
density
[N-NO3-]
20
Materials & Methods
● PARAMETERS
DESCRIPTORS
((Montecchio et al., 2004; Scattolin et al., 2012))
● NV tips (non-vital, %)
ECTOMYCORRHIZAE
● NM tips (vital non-mycorrhizal, %)
● EM ti
tips (vital
( it l ectomycorrhizal,
t
hi l %)
21
(i) Does the relative abundance of ectomycorrhizal tips differ between nonnon
declining and declining trees and between P. cinnamomi-infected and noninfected trees?
● NV (22.2  10.2 %)
● NM (29.4  11.3 %)
● EM (48.3  12.3 %)
Cenococcum geophilum
(57 %)
Tomentella spp.
(21 %)
Russula spp.
(14 %)
Others
(8 %)
22
p < 0.001
0 001
Non-vital (NV)
GENERAL MIXED MODEL
Root tips (%
%)
100
Vital non-mycorrhizal (NM)
p < 0.001
Vital ectomycorrhizal (EM)
p < 0.001
a
b
80
60
a
b
z
y
z
z
40
20
b
a
c
a
0
3
0
3
0
Non-infected
Infected
23
CAP. 2.
Ectomycorrhizal symbiosis
GENERAL MIXED MODEL
Tomentella spp.
p = 0.012
p < 0.001
Russula spp.
Other EM
EM root tips ((%)
E
60
40
a
20
0
a
a
z
a
z
z
ab
b
z
a
z
0
y
z
3
Non-infected
a
0
z
3
Infected
24
(ii) Does the ectomycorrhizal community depends on the soil properties?
Fine soil texture
Orography
Soil
NV
NM
EM
Texture
Mid
Slope
Fine
Coarse
Stream bank
Fine
C
Coarse
20.1
31.5
48.4
± 1.4
14a
± 1.8
18m
± 2.1
2 1 yz
22.7
29.7
47.6
± 1.7 ab
± 1.6 m
± 1.9 yz
25.7
28.8
45.5
± 1.9 b
± 2.0 m
± 2.1 y
20.3
27.8
51,9
± 1.5 a
± 1.9 m
± 2.0 z
Coarse soil texture
30
p = 0.049
b
b
ab
ab
ab
20
a
10
(b)
Russula spp. ro
R
oot tips (%)
GENERAL MIXED MODEL
C. geopp
philum root tipss (%)
(a)
0
0
3
0
3
p = 0.021
30
20
c
10
bc
ab
a
a
abc
ab
ab
0
0
3
Non-infected
0
3
Infected
25
(iii) Do the relations between soil properties and ectomycorrhizal abundance vary
depending on whether Q. ile x trees are declined, infected or free of infection?
PEARSON CORRELATION
Non infected
Infected
Non declining
Declining
Non declining
Declining
ns
ns
ns
ns
0.35***
0.34***
0.23*
0.36***
ns
ns
ns
ns
-0.18**
-0.19**
-0.24*
ns
0.29*
0.87***
ns
ns
Sand content (%)
-0.13**
-0.16**
ns
ns
Lime content (%)
ns
ns
ns
ns
Clay content (%)
0.14**
0.16**
ns
ns
Fine root abundance (n m-2)
0.12*
0.20**
ns
ns
Soil depth
p ((m))
Ah horizon depth (m)
Soil bulk density (g cm-3)
N-NO3- /N-NH4+ Ratio
pH
26
Section 3
Seasonal dynamics of
ectomycorrhizal
symbiosis in declining
Quercus ilex
woodlands: influence
of tree health status
and Phytophthora
cinnamomi root
infections
(Forestry, 2015)
(i) Do tree decline status and P. cinnamomi root
infections influence seasonal changes in
ectomycorrhizal fungi in Q. ilex trees?
(ii) Do the relations between the
ectomycorrhizal community and the physiology
of Q. ilex trees differ depending on whether trees
are declined, infected or free of infection?
SEECTION 3. Seasonal dynamics of ectomycorrhizal symbiosis
Materials & Methods
● STUDY SITE: 5 STANDS (EXTREMADURA)
● OROGRAPHY (topographic position)
● HEALTH STATUS (3 holm oaks WITH DECLINING SYMPTOMS
and 3 holm oaks WITHOUT DECLINING SYMPTOMS)
● PARAMETERS
Soil water
content
Stomatal conductance (gs), net leaf
photosynthesis (A) and intrinsic water use
efficiency (iWUE; A/gs )
Maximum PSII photochemical efficiency
Pre-dawn leaf water
potential (pd)
28
CAP. 3.
Ectomycorrhizal symbiosis
Materials & Methods
● PARAMETERS
DESCRIPTORS
((Montecchio et al., 2004; Scattolin et al., 2012))
● NV tips (non-vital, %)
ECTOMYCORRHIZAE
● NM tips (vital non-mycorrhizal, %)
● EM tips (vital ectomycorrhizal, %)
29
SECTION 3. Seasonal dynamics of ectomycorrhizal symbiosis
(i) Do tree decline status and P.
P cinnamomi root infections influence seasonal changes in
● NV (35.6  1.4 %)
● NM (25.5  1.2 %)
● EM (38.8  1.3 %)
(EMCg; 64 %)
Russula spp.
(EMR;13 %)
Tomentella spp.
(EMT;13 %)
Others
(10 %)
30
GENERAL MIXED
MODEL
● Year and Season for DESCRIPTORS; p<0.017
p 0.017
Cenococcum geophilum p < 0.001
Russula spp.
p < 0.001
p = 0.845
Other EM
p < 0.001
Tomentella spp.
70
60
Root tips (%
%)
50
40
30
20
10
0
Spring Summer Autumn Winter Spring Summer Autumn Winter
2009
2010
31
GENERAL MIXED
MODEL
70
Non declining (○)
Declining (●) p = 0.039
60
NV (%)
50
*
40
30
20
10
0
S i
Spring
S
Summer
A t
Autumn
Wi t
Winter
S i
Spring
S
Summer
A t
Autumn
Wi t
Winter
2009
2010
32
GENERAL MIXED MODEL
Non-vital (NV)
p = 0.016
p = 0.017
Vital non-mycorrhizal (NM)
p = 0.861
0 861
Vital ectomycorrhizal (EM)
100
Root ttips (%)
80
60
a
b
ab
b
y
z
zy
z
a
a
a
a
0
3
0
3
40
20
0
Non-declining Declining Non-declining Declining
Non-infected
Infected
33
GENERAL MIXED MODEL
Tomentella spp.
Russula spp.
p = 0.043
0 043
Other EM
p = 0.009
Root tips (%)
40
30
a
a
a
a
z
b
z
ab
b
z
ab
20
10
0
z
a
z
zy
y
y
0
3
0
3
Non-declining
Non
declining Declining Non-declining
Non declining Declining
Non-infected
Infected
34
(ii) Do the relations between the ectomycorrhizal community and the physiology of Q.
ilex trees differ depending on whether trees are declined, infected or free of infection?
CORRELACIONES DE PEARSON AND HOMOGENEITY-OF-SLOPES
HOMOGENEITY OF SLOPES
ANALYSIS
SOIL WATER CONTENT
PHYSIOLOGICAL PARAMETERS
● NM α 1 for non-declining trees
σ
● EMCg α 1 gs , A & Fv/Fm (p = 0,043, p = 0.050 an
σ
p = 0.012)
(p = 0.026)
● Other EM α σ for non-declining trees
& 1 for declining trees
σ
● EMT α σ Fv/Fm (p = 0.030)
0 023 & p = 0.003)
0 003)
● EMR α σ pdd & iWUE(p = 0.023
(p = 0.008)
● Other EM α σ pd, A & iWUE (p = 0.038,
p = 0.061
0 061 & p = 0.001)
0 001)
35
(ii) Do the relations between the ectomycorrhizal community and the physiology of Q.
Q
ilex trees differ depending on whether trees are declined, infected or free of infection?
HOMOGENEITY-OF-SLOPES
HOMOGENEITY
OF SLOPES ANALYSIS
Non declining (○)
Declining (●)
36
SECTION 4
Quercus ilex forests
are influenced by
annual variations in
water table,
bl soill
water deficit
wate
e c t aand finee
root loss caused by
Ph t phth
Phytophthora
cinnamomi
Corcobado et al. (2013) 169:92-99
Agricultural & Forest Meteorology
(i) Is oak decline related to extreme variations of
the water table depth?
(ii) Is oak decline related to low soil water
content values?
l ?
(iii) Is oak decline related to fine root loss?
SECTION 4. Influence of water table, water deficit and fine root loss
Materials & Methods
● STUDY SITE: 5 STANDS (Experiment 1) &
96 STANDS (Experiment 2) (EXTREMADURA)
● OROGRAPHY (topographic position)
● HEALTH STATUS (3 holm oaks WITH DECLINING
SYMPTOMS and 3 holm oaks WITHOUT DECLINING
SYMPTOMS)
● PARAMETERS
EXPERIMENT 1 (Monthly measurements)
EXPERIMENT 2
Soil water content () & water table
Root density
Stomatal
conductance(gs), Pre-dawn leaf water P. cinnamomi isolation
photosynthesis (A) potential (pd)
P. cinnamomi
P
isolation
38
(i) Is oak decline related to extreme variations of the water table depth?
ANOVA’s
EXPERIMENT 1
(a)
July
Aug
Sep
July
p < 0.05 (*) y p < 0.01 (**)
Aug
Sep
**
-1
-2
**
-3
(b)
p
g
p
Aug
Sep
*
10
5
Aug
Sep
Year 2009
**
July
Year 2010
*
**
0.1
0,1
0
15
y
**
July
**
gs (m
mol m-2 s-1)
g
0
0,2
-4
0.2
( )
y
(c)
A ((μmol m-2 s-1)
 pd (MPa)
0
July
Aug
Sep
July
**
Aug
Sep
39
(i) Is oak decline related to extreme variations of the water table depth?
EXPERIMENT 1
MIXED LINEAR MODEL (ANCOVA type)
Declining (●) Non-declining (○) 40
(ii) Is oak decline related to low soil water content values?
EXPERIMENT 1
Tree status (p ≤ 0.0001); tree status x season (p=0.0004)
Declining (●) Non-declining (○) 41
(ii) Is oak decline related to low soil water content values?
EXPERIMENT 1
Tree status x season x soil depth (p ≤ 0.0001)
Decliningg (●)
( )
Non-decliningg (○)
( )
42
(iii) Is oak decline related to fine root loss?
EXPERIMENT 1
P. cinnamomi
Py. spiculum
13 declining trees and 11 non-declining trees
14 declining trees and 10 non-declining trees
EXPERIMENT 2
GENERALISED LINEAL MODEL & ANOVA´s
Declining
Non-declining
Significance
P. cinnamomi-infected trees
90
63
p = 0.008
Pythium spiculum-infected trees
38
31
p > 0.1
Maximum soil depth (m)
1 18
1.18
1 23
1.23
p > 0.1
01
Coarse root abundance (roots
m-2)
7.9
6.7
p > 0.1
Fine root abundance (roots
m2)
73.7
82.9
p = 0.008
43
Section 5
Drought events
determine
performance of
Q
Quercus
ilex
il seedlings
dli
and increase
subsequent
susceptibility to
Phytophthora
cinnamomi.
(Agricultural & Forest Meteorology, 2014)
(i) Are Q. ilex seedlings able to adapt to prolonged
drought and/or waterlogging events through
physiological and growth adjustments?
(ii) Which combination of drought and
waterlogging events is more linked to higher
mortality rates?
(iii) Will these extreme events affect the response
of seedlings to subsequent infections with P.
cinnamomi?
SECTION 5. Drought events determine performance and susceptibility
Materials & Methods
2009
Acorn
sampling
p g
2010
Germination
Regular watering (Control)
n=20
2011
2012
Inoculations
Survival
assessment
Regular watering (CC)
n=20
Regular watering
n=16
Waterlogging
gg g ((WW))
n=17
Regular
g
watering
g
n=12
Water stress (WS)
n=18
Regular watering
n=12
Water stress (SS)
n=20
Regular watering
n=12
Waterlogging (SW)
n=20
Regular watering
n=9
Waterlogging (W)
n=60
Water stress (S)
n=60
60
46
Materials & Methods
Installation
Acorn
collection
Germination
Mortality
Waterlogging
Inoculation
Water
treatments
Measurements (mortality,
height, number of leaves,
photosynthesis, stomatal
conductance, root biomass)
Inoculum
Inoculum
preparation:
whole oat-grains,
vermiculite,
multivitamin juice
broth
47
(i) Are Q. ilex seedlings able to adapt to prolonged drought and/or waterlogging events through
physiological and growth adjustments? & (ii) Which combination of drought and waterlogging events is
more linked to higher mortality rates?
RESPONSE TO WATER STRESS
ONE-WAY ANOVA
Photosynthesis
y
2010
Stomatal conductance
Heigth
g
Number of leaves
C
S
W
C
S
W
C
S
W
C
S
W
4.7
±0.4
3.4
±0.4
3.1
±0.4
0.05
±0.01
0.03
±0.01
0.03
±0.01
24.5
±1.7
18.1
±0.6
18.7
±0.8
20.2
±1.4
16.3
±0.6
17.2
±0.8
GENERALIZED
LINEAL MODEL
Treatment
Mortallity after2010
treatments (%)
C
0
W
15
S
1.7
χ2= 11.15
p = 0 004
48
2011
gs
A
CC
WW
WS
SS
6.4 ± 1.8c
2.9 ± 0.7ab
2.7 ± 0.5ab
3.9 ± 0.4b
0.11 ±0.02c
50.0 ± 4.5c 41.2 ± 3.9b
(cm)
Aerial
growth
recim. aéreo,
,g
33.23
23 ± 0.35c
0 35c 22.32
32 ± 0.39b
0 39b
(g)
Root
omasa
radical, g
1.93 ± 0.39a 1.93 ±0.39a
biomass(g)
Ratio 0.54 ±0.07a
roots/aerial
ces/crecim.aéreo
growth
ratio
fine tio raíces
0.45 ±0.6a
roots/leaves
roots/leaves as/hojas
ratio
tio
1.6 ± 0.4a
F
P value
7.25 < 0.0001
0.05 ± 0.01a 0.05 ± 0.01ab 0.08 ± 0.01b 0.03 ± 0.01a 8.34 < 0.0001
Stem
height
tura
tallo,
cm
tio raíces
í
0.57 ±0.05b
Fine root/total root ratio
as/totalraíces
SW
36.1 ± 2.2ab
30.1 ± 1.6a
4.60
0.0023
1 59 ±0.39ab
1.59
±0 39ab
1 38 ± 0.39a
1.38
0 39a 1.34
1 34 ± 0.45a
0 45a 4.67
4 67
0 0020
0.0020
2.00 ± 0.39a
2.06 ± 0.39a 2.98 ± 0.39a 1.60
0.196
0.46 ± 0.05a
0.55 ± 0.05b 0.39 ± 0.04a 3.14
0.025
0.55 ± 0.07a 0,71 ± 0.07ab 0.80 ± 0.07bc 0.93 ± 0.06c 5.85
0.009
0.47 ± 0.6a
0.181
0.59 ± 0.05b
0.39 ± 0.6a
0.60 ± 0.6a
31.9 ± 4.0a
0.46 ± 0.5a
1.66
49
(ii) Which combination of drought and waterlogging events is more linked to higher mortality rates?
KAPLAN-MEIER
2011
Survival probabilitiees
P=0.037
Survival time (months)
50
(i) Are Q. ilex seedlings able to adapt to prolonged drought and/or waterlogging events through
physiological and growth adjustments? & (ii) Which combination of drought and waterlogging events is
more linked to higher mortality rates?
RESPONSE TO WATERLOGGING
ONE-WAY ANOVA
Photosynthesis
y
2010
Stomatal conductance
Heigth
g
Number of leaves
C
S
W
C
S
W
C
S
W
C
S
W
4.7
±0.4
3.4
±0.4
3.1
±0.4
0.05
±0.01
0.03
±0.01
0.03
±0.01
24.5
±1.7
18.1
±0.6
18.7
±0.8
20.2
±1.4
16.3
±0.6
17.2
±0.8
GENERALIZED
LINEAL MODEL
Treatments
Mortality after 2010
treatments (%)
C
0
W
15
S
1.7
χ2= 11.15
p = 0 004
51
2011
gs
A
Stem
height(cm)
tura
tallo, cm
Aerial
growth(g)
recim.
aéreo, g
Root
omasa
radical, g
biomass(g)
CC
WW
WS
SS
6.4 ± 1.8c
2.9 ± 0.7ab
2.7 ± 0.5ab
3.9 ± 0.4b
SW
1.6 ± 0.4a
F
P value
7.25 < 0.0001
0 11 ±0.02c
0.11
0 02
0 05 ± 00.01a
0.05
01 0.05
0 05 ± 00.01ab
01 b 0.08
0 08 ± 00.01b
01b 0.03
0 03 ± 00.01a
01 8.34
8 34 < 0.0001
0 0001
50.0 ± 4.5c
41.2 ± 3.9b
36.1 ± 2.2ab
30.1 ± 1.6a
31.9 ± 4.0a
4.60
0.0023
3.23 ± 0.35c 2.32 ± 0.39b 1.59 ± 0.39ab 1.38 ± 0.39a 1.34 ± 0.45a 4.67
0.0020
1.93 ± 0.39a
1.93 ±0.39a
2.00 ± 0.39a
2.06 ± 0.39a 2.98 ± 0.39a 1.60
0.196
Fine roots/total tio raíces
0.57 ±0.05b
root ratio
0.59 ± 0.05b
0.46 ± 0.05a
0.55 ± 0.05b 0.39 ± 0.04a 3.14
0.025
0.54 ±0.07a
0.55 ± 0.07a 0.71 ± 0.07ab 0.80 ± 0.07bc 0.93 ± 0.06c 5.85
0.009
0 45 ±0.6a
0.45
±0 6a
0 47 ± 0.6a
0.47
0 6a
0 181
0.181
as/totalraíces
Root/aerial
growth ratio
tio
ces/crecim.aéreo
Fine roots/leaves oots/
tio
raíces ea es
ratio
0 39 ± 0.6a
0.39
0 6a
0 60 ± 0.6a
0.60
0 6a
0 46 ± 0.5a
0.46
0 5a
1 66
1.66
as/hojas
52
KAPLAN-MEIER
2011
P=0.037
53
RESPONSE TO CHANGING WATERING CONDITIONS
2011
gs
A
CC
WW
WS
SS
6.4 ± 1.8c
2.9 ± 0.7ab
2.7 ± 0.5ab
3.9 ± 0.4b
0.11 ±0.02c
50.0 ± 4.5c 41.2 ± 3.9b
height(cm)
Aerial
growth
recim. aéreo,
,g
33.23
23 ± 0.35c
0 35c 22.32
32 ± 0.39b
0 39b
(g)
Root
omasa
radical, g
1.93 ± 0.39a 1.93 ±0.39a
biomass(g)
tio
0.54 ±0.07a
Roots/aerial
growth
ratio
ces/crecim.aéreo
Fine root/leaves oot/ ea es
as/hojas
ratio
tio raíces
0.45 ±0.6a
1.6 ± 0.4a
F
P value
7.25 < 0.0001
0.05 ± 0.01a 0.05 ± 0.01ab 0.08 ± 0.01b 0.03 ± 0.01a 8.34 < 0.0001
tura Stem
tallo, cm
tio raíces
í
0.57 ±0.05b
Fine roots/total roots ratio
as/totalraíces
SW
36.1 ± 2.2ab
30.1 ± 1.6a
4.60
0.0023
1 59 ±0.39ab
1.59
±0 39ab
1 38 ± 0.39a
1.38
0 39a 1.34
1 34 ± 0.45a
0 45a 4.67
4 67
0 0020
0.0020
2.00 ± 0.39a
2.06 ± 0.39a 2.98 ± 0.39a 1.60
0.196
0.46 ± 0.05a
0.55 ± 0.05b 0.39 ± 0.04a 3.14
0.025
0.55 ± 0.07a 0.71 ± 0.07ab 0.80 ± 0.07bc 0.93 ± 0.06c 5.85
0.009
0.47 ± 0.6a
0.181
0.59 ± 0.05b
0.39 ± 0.6a
0.60 ± 0.6a
31.9 ± 4.0a
0.46 ± 0.5a
1.66
54
SECTION 5.Drought events determine performance and susceptibility
RESPONSE TO CHANGING WATERING CONDITIONS
KAPLAN-MEIER
2011
P=0.037
55
SECTION 5.Drought events determine performance and susceptibility
(iii) Will these extreme events affect the response of seedlings to subsequent infections with P.
cinnamomi?
KAPLAN-MEIER
RESPONSE TO P. cinnamomi
P=0.009
2011-2012
Mortality after
P. cinnamomi
infestation (%)
CC
68.8
WW
66.7
WS
100
SS
91.7
SW
66.7
Survival prrobabilities
Treatments
χ2= 11.37
p = 0.010
Survival time (weeks)
56
Conclusions
GENERAL CONCLUSIONS
S
Stream
b k
bank
*
Fine texture
Soils with high
water-holding
t h ldi
capacity
Slope
Waterlogging
++
+++
Coarse texture
Soils with low
water-holding
capacity
p y
+
Decline
Acid pH
Ah horizon
length
+++
No decline
low
Root rot
high
Low soil bulk
density
++
+++
Decline
Ectomycorrhizal
-Abundance
+++
+
High N-NO3-/N-NH4+ ratio
++
+
P. cinnamomi
activity
Slight water
deficit
Stream
valley
Russula
R
l spp.
Other ectomycorrhizae
+
Slight
humidifying
Tree death
Slope
Stream bank
Severe water
deficit
High humidifying
+
++
*Arrows without symbol:
y
There is an association.
Arrows with symbol + : Denote an effect in the next element.
58
1. The oomycete Phytophthora cinnamomi is the main biotic factor involved in Quercus
ilex decline in Extremadura region.
2. Soil water content values are not too low to cause Quercus ilex decline or to
explain the low water potential values observed. However, if there is a reduction in
fine root density, and then, a low water-holding capacity and/or water content deficit
would originate decline.
3. Quercus ilex decline is associated with a feedback consisting in root rot, a lower
tree water uptake, then a rise in water content, favourable condition for P.
cinnamomi growth and infection, and again root rot.
44. It
I was demonstrated
d
d an influence
i fl
off soilil properties
i in
i P.
P cinnamomi
i
i activity
i i and
d in
i
decline intensity. Fine texture and thicker Ah horizons, which are positive soil
properties for the vigour and tree vitality under a Mediterranean climate, favour
tree decline wether P.
P cinnamomi is present.
present These soil properties in combination
with orographic position which keep high soil humidity, benefit P. cinnamomi activity
and contribute to decline.
59
5. Q. ilex decline is independent of soil compaction and mineral N content (within
the studied ranks), parameters related to grazing. However, the significant relation of
decline to nitrate/ammonium ratio could be associated to the pprogressive
g
soil
degradation in the studied agroforestry systems.
6. Q. ilex decline was related to the vitality of the root system; but not with the
ectomycorrhizal abundance in several stands.
7. Ectomycorrhizal abundance was higher in spring and summer than in autumn and
winter. Neither the holm oak health status or P. cinnamomi presence influenced the
seasonal dynamic of the ectomycorrhizal abundance and diversity. The percentage of
dead root tips varied depending on the season and the tree health status, being
especially
i ll higher
hi h in
i declining
d li i than
h in
i non-declining
d li i trees during
d i summer.
8. The presence of the pathogen alter the abundance of the ectomycorrhizal
morphotypes less abundant in declining and non-declining
non declining trees,
trees being the
abundance higher in infected non-declining trees.
60
9. A lower percentage of mycorrhizal root tips was detected compating to other
studies with holm oak. The ectomycorrhizal diversity was also poor in the studied
stands which is consistent with the degradation
g
of the holm oak woodlands.
Cenococcum geophilum, Russula spp. and Tomentella spp. were the most abundant
morphotypes.
10. The relation between the abundance of some ectomycorrhizal morphotypes and
Q. ilex physiology changes depending on the tree health status. The relation between
stomatal conductance or photosynthesis and C. geophilum abundance turned
negative for the declining trees, while this relation becomes positive with Russula
spp. for declining trees and negative for non-declining trees.
11. The
11
Th ectomycorrhizal
hi l community
i was influenced
i fl
d by
b the
h soilil properties,
i increasing
i
i
its abundance with those soil porperties associated with soil fertility (Ah horizon
thickness, pH and clay content), and influenced by the topographic position. The
presence of the pathogen weakens the natural association between soil properties
and ectomycorrhizal abundance.
12. Q.
12
Q ilex seedlings exposed to prolongued or recent drought events followed by P.
P
cinnamomi infection, are more predisposed to death than those under higher soil
water content conditions, including waterlogging.
61
ACKNOWLEDGMENTS
Financed
i
by: the agreement between the University off Extremadura and Extremadura government, and
within the action COST “Established and emerging Phytophthora: increasing threats to woodland and forest
ecosystems in Europe” (FP0801). Financed also by Extremadura government (regional proyects III-PRI 08A78 & IV
IV-PRI
PRI IB10088), European funds and by the Sciences and Innovation Government (AGL2007
(AGL200764690/AGR & AGL2011-30438-C02-02).
THANK YOU
VERY
MUCH!

corcobado

Transcription

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