Adel-maize and Adel wheatas tools for simulating the dynamics of 3D canopies

Bruno Andrieu and Christian Fournier

INRA, UMR EGC 78850 Thiverval-Grignon

Bruno.andrieu@grignon.inra.frChristian.Fournier@grignon.inra.fr

Why models of plant architecture ?

• Component of FSPMs

• Tools to simulate the time curse of 3D canopy structure – Modelling the environment perceived by

individual plant organs – Improving prediction of statistical

variables

• Intermediate approachs : eg 3D models interfaced with crop models

Specific aspects

• Kinetics of development, extension and senescence of individual plant organs

• Patterns of size of mature blade, sheaths, internodes

• 3D geometry– Leaf geometry and orientation– Axe orientation

Adel-maize

Scheme of development

Schedule of organ extension

0

3

6

9

12

15

18

0 300 600 900

Thermal time (°Cj)

Ran

k of

the

Phy

tom

er

Size of mature leaves along the shoot

0

200

400

600

800

1000

1200

0 10 20 30Phytomer number

Are

a of

the

lam

inae

(cm

²)

Parametrisation of midrib curvature

Prévot et al, 1991

Ax²+bxcx²+dy²+e=0

Phi ?

Measured vs simulated light interception

Tau

x de

cou

vert

ure

Indice foliaire

,

,

,

, ,

Exemple of application B. Andrieu, G. Popa, Y. Sohbi, C. Fournier

•A field experiment was reproduced in silico, enabling incident PAR to be calculated for all individual leaf

Final width of all laminas above 4 could be interpreted as the product of two simple functions : Wmax = (n) *f(E)

(n) f(E) # ln(E)

0

0,5

1

0 10000 20000 30000 40000

Cumulated flux (KJ/m²)

f(E

)

F4 à F6

F7 à F9

F10 à F13

F14 à F16

0,139*log(E/14,3414)

0

5

10

15

0 5 10 15Phytomer

(n

)

•Thus response of width of lamina to density appear to be a function of local light availability.

In progress• Ability to simulate a range of

contrasted genotypes• More generic description of leaf

geometry• Investigation on plasticity of

architecture under contrasted environmental conditions (density, cold).

Still far from mechanistic simulation

But good progress in identifying the degree of freedom

Wheat architecture

D 250

T0

T1

f11 f 12

D 70

T1

T0

Feuille

Entre-nœud

Bourgeon axillaire

PHYTOMERE

f8 f7f7f 9

f 8 f 7

f 8f 6f 6

Size of matures laminae along the shoot

D 70

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Phytomer

Le

ng

th o

f la

min

ae

(c

m)

T0

T1

T2

T3

T4

T5

T6

D 70

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Relative phytomer number

bm

t1

t2

t3

t4

t5

t6

Le

ng

th o

f la

min

ae

(c

m)

A unique shift applies to laminae, sheath and internodes

Sheath D70

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Relatif phytomer number

Lo

ng

uer

(cm

)

bm

t1

t2

t3

t4

t5

t6

len

gth

(cm

)

Entrenoeud D70

0

5

10

15

20

25

30

35

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Phytomere relatif

L en

tren

oeud

bm

t1

t2

t3

t4

t5

t6

Kinetics of leaf extension follows a single pattern

along the shoot

See also Fournier et al New Phytol 2005

Prevot et al (1991) maize leaf fitted to wheat leaves

See also Fournier et al 2003 in PMA03Evers et al, New Phytol 2005

In progress• with UCL (J. Watt, J. Hillier, P. Lewis)

– Multi-genotype version– Duration of leaves– Use in Remote sensing

• With WUR (J. Evers, J. Vos)– Extension to spring wheat– Tillering– Incorporating photosynthesis

Blade length

Sheath length

Internode length

After J. Watt

To be further investigated

• Still few is known about the quality of 3D representation for RT investigations– Tropism, shade avoidance <-> clumping

• How far can we decrease the number in model parameters (due to low RT sensitivity, or stable patterns)– eg in describing leaf shape (in progress)

• Genericity over a range of genotypes, species

Remaining to be modelled

• Distribution and time curse of leaf exchange properties (Cab, H20, etc ..) and death to drive a leaf reflectance model

• How kinetics of extension and mature size of organs is driven by environment (H20, Nitrogen, density)

• Ear development and optical properties

In progress• with UCL (J. Watt, J. Hillier, P. Lewis)

– Multi-genotype version– Duration of leaves– Use in Remote sensing

• With WUR (J. Evers, J. Vos)– Extension to spring wheat– Tillering– Incorporating photosynthesis