Thermal Time normalization
Thermal time normalization makes it possible to compare plant growth for both organogenesis (organ numbering) and development (organ size) aspects.

Light interception: PAR, LAI and the Beer-Lambert Law
Only part of light energy is used in plant crops. A limited fraction of the light spectrum is absorbed by the leaves; this part is restricted to the upper leaf area and decreases in the canopy.

Photosynthesis, Light Use Efficiency
The photosynthesis process converts absorbed light energy into biomass with a ratio proportional to Light Use Efficiency.

Biomass common pool
Biomass produced by the source organs (leaves) builds a common storage pool, to be shared among all competing growing organs.

Organ competition. Sinks
Growing organs compete for biomass allocation. They are sinks.

Density effect
At individual plant level, density limits light absorption capabilities, and thus dynamically limits biomass production.