Abstract:
Amphicarpic plants produce both subterranean and aerial fruits on a single plant, which is a bet-hedging strategy for plant adaptation in the face of temporal and spatial variations in environmental conditions. Amphicarpaea edgeworthii (Leguminosae), an annual amphicarpic herb grows within wet to dry habitats, and exhibits considerable morphological variation. To understand the adaptation of A. edgeworthii to water availability, we studied plant growth and reproductive responses from subterranean seeds (SSP) and aerial seeds (ASP) from A. edgeworthii under 300, 450, 600, 750 and 900 mm of rainfall amounts. Vegetative biomass, plant height, leaf biomass, number of leaves, and number of branches in SSP were remarkably increased relative to those in ASP, while root / shoot biomass ratio was lower in SSP. With an increase in water availability, reproductive biomass, aerial reproductive biomass, and subterranean reproductive biomass gradually increased. Aerial reproductive biomass changed more significantly than subterranean reproductive biomass. SSP produced more seeds than ASP. With an increase in water availability, seed mass decreased. Results showed that A. edgeworthii exhibits potent plasticity to respond to the extent of water availability, which enhances the survival and reproductive capacities under uncertain environmental conditions.
Keywords:
Amphicarpy
,
biomass allocation
,
water availability
,
Amphicarpaea edgeworthii