Allometric Relationships between Dry Matter Weights of Maize Organs and Their Responses to Drought

To understand the drought response mechanisms of dry matter partitioning of maize, pot experiments under drought conditions were conducted during the vegetative and reproductive growth periods of maize. The aim was to calculate allometric relationships between the dry matter weight of different organs and their responses to drought. Results showed that allometric relationships between the roots, above-ground plant, and total biomass gradually increased with maize growth approaching maturity under a normal water supply. Drought during the vegetative period reinforced allometric relationships during the growth process and after rewatering and increased the size-dependence of the root shoot ratio. However, drought during the reproductive period weakened them. The ear–shoot allometric relationship was more significant during growth than at later growth under normal conditions but strengthened during later growth in those plants suffering droughts during the vegetative and reproductive stages. The ear–shoot allometric relationship and the size-dependence of harvest index at later growth were significantly enhanced by drought during the reproductive period compared to the vegetative period.