Allometric relationships of canopy development in rice and maize

Functional-structural plant modelling requires the linkage of plant physiological function and its structure at organ level for improved ability in agronomic application. Allometric relationships among organ development represent endogenous coordination that can be used to bridge plant morphology and function. However, there are insufficient allometric relationships available. This study aimed to investigate allometric relationships between organ morphology and biomass (physiological phenotypes) using data from a glasshouse experiment of rice (Nippon Bare and a mutant with low tillering) and a field experiment of maize (Pioneer 34N43 and 31 H50). Allometric relationships were determined with the highest coefficients of determination (R²). Leaf area and fresh biomass relationship was fitted by a linear function for rice, and linear function for phytomers at the ear and below, but replaced by a curvilinear function for phytomers above the ear, in maize. Leaf lamina length and biomass was fitted by exponential functions for both rice and maize. Sheath length and biomass relationship was fitted by a logarithmic function for rice (maximum 9 sheaths) and for phytomers below 9 in maize and an exponential function for phytomers above 8 in maize. Intemode length and biomass was fitted by two exponential functions separated at ear position in maize only, since no data exists on internodes in rice. This study indicated that organ morphology can be predicted from crop physiological process, which facilitates the establishment of feedback of structure and functions of plant modeling.