This study examined the effect of drought acclimation and drought stress history on potato genotypes. Drought acclimation led to more small tubers, higher water use efficiency, and smaller stomatal and cuticle sizes compared to non-acclimated plants. Russet Burbank recovered fastest from severe drought stress. Further experiments will investigate the effects of multi-generational drought stress history on yield components and physiological parameters related to drought resistance.

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Effect of drought acclimation and previous drought
stress history upon drought stress resistance in
contrasting potato genotypes
Pankaj Banik (M.Sc. student)
Helen Tai, Benoit Bizimungu and Karen Tanino

2. Drought stress in potato undergrowth
 Sensitive to drought
• Even a short period of time
• Tuber quality & production
 Stolon formation & tuberization
• Most sensitive stage
• Longer period in tuber formation
• Decrease in tuber number, growth & yield
4 flowering stage

3. Greenhouse Low RH room
(22/20°C, 17-25% RH, 250 µmol/m2/sec)

4. Applying drought stress
0
5
10
15
20
25
30
35
Soilmc%
1st DA 2nd DA 1st DS 2nd DS1st R 2nd R
Drought acclimated & stressed (DAS)
Non acclimated but stressed (NAS)
Non acclimated & non stressed (NA)

5. Stress & Recovery
Severe stress (scale 3)
After recovery (scale 0)
Score % leaves wilted
0 None
1 25%
2 50%
3 75%
4 100%
5 Plant died

6. Hypotheses
 Drought acclimation and recovery are key components
of resistance
 Stomatal aperture parameters are associated with yield
under drought stress conditions
 Drought stress history of genotypes affects subsequent
drought stress resistance

7. Experiment layout (no stress history)
Genotypes Treatments Codes
Fv12246-6
(Fv)
NA (Non Acclimated) Fv-NA
DAS (Drought Acclimated & Stressed) Fv-DAS
NAS (Non Acclimated & Stressed) Fv-NAS
V1002-2
(V)
NA V-NA
DAS V-DAS
NAS V-NAS
Russet Burbank
(RB)
NA RB-NA
DAS RB-DAS
NAS RB-NAS

8. Significant difference among treatment groups across different weight
classes. Drought acclimated & stressed plants (DAS) induced more small
tubers (<5g)
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Fv-NA
Fv-DAS
Fv-NAS
RB-NA
RB-DAS
RB-NAS
Tuber number
Treatments
<5g
5-20g
20-50g
50-100g
>100g
↙
↙

9. Drought acclimation increased WUE over controls (DAS > NA). However, NAS WUE was
greater than DAS. Russet Burbank (RB) maintained highest WUE but acclimated-
stressed treatment (RB-DAS) acquired lower leaf %N than controls (RB-NA)
Treatments ∆
Fv-NA 20.74
Fv-DAS 21.89
Fv-NAS 19.83
V-NA 22.71
V-DAS 22.43
V-NAS 20.33
RB-NA 20.25
RB-DAS 20.56
RB-NAS 18.57 0
1
2
3
4
5
6
7
8
Fv-NA Fv-DAS Fv-NAS V-NA V-DAS V-NAS RB-NA RB-DAS RB-NAS
%leafN
Treatments
A
A
A
a
a
a
*
*
Highly significant difference (p<0.01)amongtreatmentgroups
RB-NA> RB-DAS***
WUE % Leaf N

10. Fv-DAS V-DAS RB-DAS
Fv-NAS V-NAS RB-NAS
Preliminary SEM results showed differences in cuticular and
stomatal morphology
Fresh sample SEM by low vacuum JEOL JSM 6010

11. -500
0
500
1000
1500
2000
2500
3000
Fv-NA Fv-DAS Fv-NAS RB-NA RB-DAS RB-NAS
Areaofstomatalopening(µm2
)
Treatments
a
ab
c
ac
ae
bc
Overall highly significant difference (p<0.001) among treatment groups
Fv12: NA > NAS *** , DAS > NAS ***
RB: DAS > NAS ***
Stomatal aperture (400X)
Acclimation induced
wider stomatal
opening at maximum
stress
Acclimation induced
smallest stomatal size in
Fv12.
Stomatal size did not
change in RB treatments
0
5000
10000
15000
20000
25000
30000
35000
40000
Fv-NA Fv-DAS Fv-NAS RB-NA RB-DAS RB-NAS
Sizeofstomata(µm2)
Treatments
a
b
c
c
c c
Overall highly significant difference (p<0.001) among treatment groups
Fv12: NA > NAS > DAS

12. Acclimation and a series of stresses (DAS & NAS) induced smaller cuticle
platelet size compared to controls (NA) in both genotypes
0
10000
20000
30000
40000
50000
60000
70000
80000
Fv-NA Fv-DAS Fv-NAS RB-NA RB-DAS RB-NAS
Areaofcuticleplatelets,micron
Treatments
a
b
bc
a
b
b
Overall highly significant difference (p<0.001) among treatment groups
Both genotypes: NA is significantly higher than both DAS & NAS
RB-NA RB-DAS RB-NAS

13. 0
1000
2000
3000
4000
5000
6000
7000
8000
9000
Fv-NA Fv-DAS Fv-NAS RB-NA RB-DAS RB-NAS
Areaofxylemvessel(µm2
)
Treatments
a
b
ab
ab
ab
ab
Overall significant difference (p<0.05) among treatment groups
Stem cross-section (25X)
Xylem cross-section (250X)
Xylem vessel area measured were not related to drought acclimation. But stem %WC
was significantly different among genotypes and treatments
80.0
82.0
84.0
86.0
88.0
90.0
92.0
94.0
96.0
98.0
Fv-NA Fv-DAS Fv-NAS V-NA V-DAS V-NAS RB-NA RB-DAS RB-NAS
Stemwatercontent(%)
Treatments
Overall highly significant difference (p<0.001)
among genotypes & treatment groups
V1002 > Fv12 ***, RB > Fv12 ***
aj
deg
ab
cj
dj
aefj
gj
ehj
aih

14. 22.3 oC 24.2 oC
NAS DAS
Maximum stress
(soil mc is 0% over 1 week)
Russet
Burbank
recovers
After 5 hrs of watering
NAS DAS
19.5 oC 19.6 oC
V1002 recovers within 12 hours
Fv takes 16 hours
Russet Burbank (RB) recovers much more quicker than Fv12 &
V1002 after undergoing maximum drought stress

15. Hypotheses
 Drought acclimation and recovery are key components
of resistance
 Stomatal aperture parameters are associated with yield
under drought stress conditions
 Drought stress history of genotypes affects subsequent
drought stress resistance

16. Drought stress History over 3 generations
Generation 1 NA
(Non Acclimated)
DA
(Drought Acclimated)
Generation 2 NA-NA NA-DAS NA-NAS DA-NA DA-DAS DA-NAS
Generation 3 NA-NA-NA NA-DAS-NA NA-NAS-NA DA-NA-NA DA-DAS-NA DA-NAS-NA
NA-NA-DAS NA-DAS-DAS DA-DAS-DAS
NA-NA-NAS NA-DAS-NAS DA-DAS-NAS
}
}
}

17. Overall highly significant difference (p<0.01) among
treatments across weight classes
0 10 20 30 40 50 60 70 80 90
NA-NA-NA
NA-NA-NAS
NA-NA-DAS
NA-DAS-NA
NA-DAS-NAS
NA-DAS-DAS
DA-DAS-NA
DA-DAS-NAS
DA-DAS-DAS
Gross Tuber No.
Treatments
<5g
5-20g
20-50g
50-100g
>100g

18. Further work
 To address
• Drought stress history of genotypes affects
subsequent drought stress resistance
• Yield
• Stomatal aperture measurement
• Cuticle platelet size
• Cuticle layer thickness
• WUE and NUE
• Recovery rate

19. Summary
 Under drought stress, drought acclimation induced:
• more small tubers (<5g)
• higher WUE over controls and lower % leaf N in Russet Burbank
DAS
• Smallest stomatal size in Fv12
• Wider stomatal opening at maximum stress
• Smaller cuticle platelet size over controls
 Recovery rate from severe stress:
• Russet Burbank had fastest recovery time (5 hrs) after
stress followed by V (12 hrs) and Fv (16 hrs)

20. Acknowledgements
Supervisor
Prof. Karen Tanino
Funding agency
SAGES Project
Committee
Prof. Bruce Coulman
Prof. Tom Warkentin
Prof. Gordon Gray
Greenhouse Team
Eldon Siemens
Jackie Bantle
SEM
Guosheng Liu
Rob Peace
Mass Spec
Darin
Myles Stocki
Statistics
Prof. Sakti Jana
Prasanto Mondol
Spatial analysis
Dr. Winston Zeng
Ting Pei
Lab members
Jun Liu
Jihua Xu

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Thank you