What makes trees so different?

Phenotyping drought stress tolerance in Populus tremula

Wageningen, October 14th 2011

Faculty of Forest-, Geo-, Hydrosciences, WG molecular physiology of woody plants

Doris Krabel, Matthias Meyer, Bjrn Gnther, Gerd Helle

Trees are organisms of a long life

Age of some forest trees:

Quercus spec.: 750 years

Tilia spec: 600 years

Fagus sylvatica: 400 years

http://de.wikipedia.org/wiki/Hutebaum

- http://de.wikipedia.org/wiki/Eiche_am_Emmertshof

What makes trees so different?

TU Dresden, Oct.14th 2011 Doris Krabel et al. Slide 2

What makes trees so different?

- Period of reproduction starts late (earliest flowering of

forest trees after around 10-15 years, depending on

the species)

breeding takes time!!!

TU Dresden, Oct.14th 2011 Doris Krabel et al. slide 3

What makes trees so different?

- They are tall

http://www.waldwissen.net/technik/holzernte/ar

beit/wsl_langseiltechnik/index_DE

http://www.sz-

online.de/nachrichten/artikel.as

p?id=2705236

1 year old poplar

Foto: K. Morgenstern

What makes trees so different?

TU Dresden, Oct.14th 2011 Doris Krabel

slide 5

Foto: K. Morgenstern

What makes trees so different?

- Traits of interest are usually first apparent after

decades of vegetation cycles

TU Dresden, Oct.14th 2011 Doris Krabel et al.

slide 6

What makes trees so different?

- Not always easy to propagate

Root cuttings of trembling aspen (Populus tremula)

What makes trees so different?

TU Dresden, Oct.14th 2011 Doris Krabel et al.

slide 8

- compared to other organisms trees show a high genetic diversity

Species

Chromosome number (n)

Genome size (bp x 106)

Number of genes (n)

Escherichia coli - 41,000

Homo sapiens 23 ca. 3,000 < 25,000

Pinus sylvestris 12 ca. 25,000 unknown

(modified after Finkeldey 2010)

Traits of interest

- Wood quality: stem straightness or crookedness, basal

sweep; crown architecture as a whole; forking and

associated defects (ramicorns etc.); branching pattern

(thickness, angle, density); chemicals, wood anatomical

traits

TU Dresden, Oct.14th 2011 Doris Krabel et al. slide 9

Traits of interest

- Stem architecture as a whole

TU Dresden, Oct.14th 2011 Doris Krabel et al.

slide 10

Traits of interest

TU Dresden, Oct.14th 2011 Doris Krabel et al. slide 11

- Resistance/tolerance to pest and diseases (depends on the

species)

- Early and constant flowering (for breeding purposes)

- Resistance/tolerance to abiotic stress (e.g. drought, early

frost, late frost, winter frost)

- Fast growth (e.g. for energy purposes)

- water demand economics - water deficit adaptations

reference for SRC locations: Landgraf (P&P) pers. communication,

no guarantee for completeness

Demand for

tree breeding:

Minimisation of yield

losses under water deficits

Climatic water balance for

Germany; period

01.05. 31.08.2010

Why drought tolerance in Poplar?

The approach

comparison group

ca. 400 aspen trees

free succession

(different age)

mapping population 103

aspen trees

F1 crossbred family

(1998 2003)

QTL-Mapping for water deficit tolerance related traits

yield (radial increment,

aggregate woody biomass)

carbon isotope ratio (13C)

fibre / vessel element length

vessel lumen cross-sectional area

wood density (X-ray densitometry)

Physiological/ anatomical traits

tree ring

archive

How to phenotype drought tolerance in trees?

Methods for measuring fibre and vessel length, wood density, radial increment

North

South

How to phenotype drought tolerance in trees?

Periods of water deficit

mo

nth

ly p

recip

ita

tio

n

[mm

]

30 20 10

0

-6.0

-6.5

-7.0

-7.5

-8.0 de

pth

to

gro

un

dw

ate

r

[m u

nd

er

TG

S]

240

140 120 100 80 60 40 20 0

2000 2003

9.5 C 9.9 C 10.6 C 9.1 C 9.8 C 9.7 C

me

an

mo

nth

ly

tem

pe

ratu

re

[C

]

month in year

month in year

Mapping population

Radial increment (ir)

[m

m]

4.00

3.00

2.00

1.00

0.00

1 2 3 4 5 7 6 8 9 10 1

2 3 4 5 7 6 8 9 10

comparison group mapping population

tree ring

3.00

2.00

1.00

0.00

4.00

1,10 0,88 0,84

1,97

2,35 2,54

1,17

2,17 2,26

2,78 2,84

3.27 3,01

2.58 2.57

2,00

tree ring

Results

1998 2003

1.40

1.60

1.00

0.80

0.60

0.40

0.20

1.20

[1

0-

mm

]

0.45 0.44 0.46

0.85

0 .89

tree ring

1 2 3 4 5 6

Results

Mean vessel lumen

cross-sectional area (AG)

0.71

Mapping population

548

514 518

543

426

(g

/cm

)

0.40

0.65

0.60

0.55

0.50

0.45

588

548

518

551 550 546 558 549

534 525

585

1 2 3 4 5 7 6 8 9 10 1 2 3 4 5 7 6 8 9 10

Mean wood density (XD) - assessed by X-ray densitometry

comparison group mapping population

tree ring tree ring

Results

0.40

0.65

0.60

0.55

0.50

0.45

Results

Vessel- and fibre cell length juvenile trend of cell length

Vessel lumen cross-sectional area, tree ring 2003

Results

Concluding remarks

TU Dresden, Oct.14th 2011 Doris Krabel et al. slide 22

- Phenotyping drought tolerance in trees is possible

by investigations on a combination of wood anatomical traits

- The specific developmental stage of the plant has to be

taken into consideration (juvenile trends)

We are far away from high throughput phenotyping in trees!

200 years of forestry education in Tharandt

www.

.org

Acknowledgement

Free State of Saxony, Ministry of

Environment and Agriculture

www.TU-Dresden.de/Forst/ISOWOOD

ISOWOODISOWOOD

breedingbreeding

1313CC

ISOWOODISOWOOD

breedingbreeding

1313CC

Acknowledgement