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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

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

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

Applying drought stress

0

5

10

15

20

25

30

35

So

il m

c%

1st DA 2nd DA 1st DS 2nd DS 1st R 2nd R

Drought acclimated & stressed (DAS)

Non acclimated but stressed (NAS)

Non acclimated & non stressed (NA)

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

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

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

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

Trea

tmen

ts <5g

5-20g

20-50g

50-100g

>100g

↙

↙

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

% l

ea

f N

Treatments

A

A

A

a

a

a

*

*

Highly significant difference (p<0.01) among treatment groupsRB-NA > RB-DAS ***

WUE % Leaf N

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

-500

0

500

1000

1500

2000

2500

3000

Fv-NA Fv-DAS Fv-NAS RB-NA RB-DAS RB-NAS

Area

of st

omat

al op

enin

g (µm

2 )

Treatments

a

ab

c

ac

ae

bc

Overall highly significant difference (p<0.001) among treatment groupsFv12: 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

Size

of s

tom

ata

(µm

2 )

Treatments

a

b

c

c

c c

Overall highly significant difference (p<0.001) among treatment groupsFv12: NA > NAS > DAS

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

Are

a of

cuti

cle

plat

elet

s, m

icro

n

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

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

Fv-NA Fv-DAS Fv-NAS RB-NA RB-DAS RB-NAS

Area

of xy

lem

vess

el (µ

m2 )

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

Stem

wat

er co

nten

t (%

)

Treatments

Overall highly significant difference (p<0.001) among genotypes & treatment groupsV1002 > Fv12 ***, RB > Fv12 ***

aj

deg

ab

cj

dj

aefj

gj

ehj

aih

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

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

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

}

}

}

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.

Tre

atm

en

ts

<5g

5-20g

20-50g

50-100g

>100g

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

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)

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

www.usask.ca

Thank you