Allometric Relationships of Maize Organ Development under Different Water Regimes and Plant Densities

Abstract

Allometric relationships of plant organs reflect internal coordination of different aspects of organ development, allowing the linking of plant structural development and underlying physiological processes for the development of functional-structural plant models (FSPMs). This paper aims to (i) explore the allometric relationships between organ morphology and fresh biomass in maize; (ii) develop equations to describe these relationships; and (iii) examine the response of allometric relationships to crop water availability and plant density. Datasets were obtained from field experiments in which three commercial maize cultivars (Pioneer 34N43, Pioneer 31H50 and NongDa 108) were grown under different water regimes and plant densities. Relationships are described between (i) lamina length and biomass for all phytomers by a power function, (ii) lamina maximum width and biomass by a power and a logarithmic function separated at ear position, (iii) sheath length and biomass by power and logarithmic functions separated at eighth sheath position where the sheath length peaked, and (iv) internode length and biomass by two power functions separated at the ear position across water regimes and plant densities. The allometric relationships of organ development were not affected by the mild water stress, but were modified by the increased plant densities. Consequently, the allometric relationships found in this study and their expressions using mathematical equations enable plant morphology to be predicted from physiological output (biomass accumulation), which provides a biologically robust mechanism of realizing functional-structural communication used in FSPMs.