3d root model: exploring root developmental plasticity to...

3D root model: Exploring root developmental plasticity to soil

nutrients

Sarlikioti V, Pagés L, et al.

Nutrient distribution Root plasticity

Root plasticity Nutrient uptake

3D dimenional: nutrient distribution x root plasticity

To include the plasticity mechanisms:

of root perception and orientation towards nutrient rich zones (Chemotropism)

of adaptation of the linear branching density (IBD)

of the relative growth rate modification of the lateral roots relatively to the mother root (RMDB)

To study the effect of such mechanisms on rootarchitecture and uptake at the root level for four different nutrient scenarios

Layer

Patch

Gradient

Random

Nitrogen sources (3500 sources, d= 0.005m)

Phosphorus sources (2000 sources, d= 0.002m)

Root model 3 modules

Root Meristem

Root Segment

Root Primordium

Meristem length += Actual Growth Rate

Root segment length (SRL)= constant

no Segments= meristem length/SRL

Uptake occurs at the meristem level

If the distance between nutrient source and the root

meristem >= a defined distance

Source uptake

The distance is defined according to the mobility of

each source

No nutrient movement is considered at this stage

Inter-Branching Distance (IBD)

Maximal diameter of the root branch (RMDB)

Chemotropism

The root turns towards a nutrient source if:

The source should be within a defined cone with root meristem as its apex.

The distance between the root tip and the source is equal or smaller a threshold distance.

No distribution Patch distribution

Segment Length = SRL –α*Local_uptake

Local_uptake= average uptake of the last three days

SRL, α are constants

Local_uptake

Segment length

SRL

Patch distribution Random gradient distribution

Primodium diameter =

MRD *(α+β*local uptake)*exp(VAR*R)

Local_uptake= average uptake of the last three days

MRD, α, β are constants

Local_uptake

Primordium Diameter

MRD

Mother Diameter

Daughter Diameter

MRD

Patch distribution Random gradient distribution

Root uptake

Significant effect of nutrient distribution on root

plasticity and architecture

Nutrient uptake higher for gradient and layer

distributions

Most efficient plasticity scenarios

MRDBIBDChemotropism