Root phenotyping€¦ · Static root traits – measured at single time point Dynamic root traits – related to dynamic changes Nagel et al. 2009, Functional Plant Biology Nagel

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Root phenotyping at Jülich Plant Phenotyping Centre (JPPC)

new routes to explore non-invasively the hidden half of plants

Kerstin A. Nagel - 17/02/2014

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Phenotyping the hidden half of plants – Why?

• Root system architecture can strongly affect yield

• Sustainable plant production requires root systems

optimised for growing conditions in the field

• Many of the traits required in future crops are tightly

linked to root properties:

- abiotic/biotic stress tolerance

- water and nutrient use efficiency

- yield...

However, root phenotyping is a challenging task,

mainly because of the hidden nature of this plant organ

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Non-invasive phenotyping of roots

• Allows repetitive analysis of the same plant or plant organ

• This enables finding phenotypic differences that occur:

- transiently

- at certain developmental stages

- under certain environmental conditions

• Combined with robotic systems – enables high-throughput screening

of large numbers of genotypes

• Overcome the phenotyping bottleneck

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Fiorani et al. 2012, Current Opinion Biotechnology

Non-invasive technologies are key to quantify plant structure and function

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Imaging plant function and structure is more than ‘taken pictures‘

Aim: measuring

quantitatively traits

Interpretation of images requires knowledge of

• sensor physics • sensor calibration • image analysis • plant traits

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Requirements for high throughput phenotyping

Automation of:

• quantitative image analysis

• plant cultivation (sowing – harvest)

• environmental monitoring

• data storage

• quality monitoring

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Development of root phenotyping facilities at JPPC

• reproducibly quantification of growth and architecture of roots

• elucidating dynamic establishment of roots in space and time

• interaction of root responses with aboveground plant part

• from artificial growth media to soil

• from controlled conditions to field environment

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Throughput: 300 plants – 15 min

Concept: plant-to-sensor

Nagel et al. 2009, Functional Plant Biology

Root phenotyping in artificial growth media

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Image analysis - quantify root system architecture

A

D C

B

• Image preprocessing

• Identification of local root elements

• Concatenating local root elements by following roots

• Crossings and branching

Mühlich et al. 2008, LNCS Nagel et al. 2009, Functional Plant Biology

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Root traits Global root traits • total root length • spatial distribution of roots

- root length density - rooting depth - root system width - area covered by roots

Root traits derived from individual roots • root length • number of roots • root diameter • branching angle

Static root traits – measured at single time point Dynamic root traits – related to dynamic changes

Nagel et al. 2009, Functional Plant Biology Nagel et al. 2012, Functional Plant Biology

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Nagel et al. 2009, Functional Plant Biology Füllner et al. 2012, Plant, Cell and Environment

Vertical temperature gradients for more realistic representation of field heterogeneity

Biomass (g)

Root temperature treatment (°C) 10 15 20 20-10

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Branching angle of laterals is temperature dependent

Time after sowing (d)4 6 8 10 12 14

Branching angle (°)

40

45

50

55

60

65

70

75

10°C 15°C 20°C 20-10°C

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Root phenotyping of soil grown plants

Throughput: 60-240 plants – 60 min Concept: sensor-to-plant / plant-to-sensor Nagel et al. 2012, Functional Plant Biology

GROWSCREEN-Rhizo

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Simultaneous phenotyping of root and shoot traits

Shoot traits

Root traits

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Projected shoot area - 2D images (cm²)

0 100 200 300 400 500 600

Shoot biomass (g)

0

5

10

15

20

R² = 0.9505

Projected shoot area correlates with shoot biomass


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Some parts of the root system are hidden in the soil

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0° 25° 43°

Ratio

visibl

e vs.

total

root le

ngth

(%)

0

10

20

30

40

Visible portion of a root system depends on the inclination angle of rhizotrons

α β


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Plant species Visible portion of root system

Arabidopsis 77%

Rapeseed 42%

Barley 33%

Wheat 33%

Rice 32%

Brachypodium 24%

Maize 17%


Visible portion seems to depend on root diameter

Arabidopsis Maize

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Visible root length correlates with total root length

Total root length (cm)0 500 1000 1500 2000 2500 3000

Visible root length (cm)

0

100

200

300

400

500

600

700

800

900

BarleyR² = 0.91


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Root biomass (mg)0 20 40 60 80 100 120

Visible root length (cm)

0

100

200

300

400

500

600

700

800

900

BarleyR² = 0.92


Visible root length correlates with root biomass

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Mechanical impedance affects root system architecture


Time after sowing (d)6 8 10 12 14 16 18 20

Root system length (cm)

0

100

200

300

400

500

Low compactionModerate compaction

Root length density (cm cm-2)0.0 0.1 0.2 0.3 0.4 0.5

Depth (cm)0

20

40

60

80

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Pfeifer et al. 2014, Functional Plant Biology

On ‘low compacted side‘ of split root system • roots grow deeper and • lateral roots emerged earlier

Time after transplanting (d)

Lateral root development

low high

Split-root

high/high

low/low

Barley roots respond to localized soil compaction

low/low high/high low/high Split-root

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Root phenotyping non-invasively

• Screening for phenotypic plasticity

• Selection of root system architecture ideotypes for improved resource

use efficiency

• Identification of candidate genotypes with improved plant productivity

• Development of new phenotyping concepts for crop breeding

Root phenotyping€¦ · Static root traits – measured at single time point Dynamic root traits – related to dynamic changes Nagel et al. 2009, Functional Plant Biology Nagel

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