Biological and adaptive significance of the amphicarpy of Amphicarpaea edgeworthii
Amphicarpic plants produce aerial and subterranean fruits on an individual plant, and these heteromorphic diaspores give rise to plants that differ in growth and ecology. I use field surveys, anatomical and physiological tools determined the adaptive significance of the amphicarpic plants Amphicarpaea edgeworthii. I found that (1) aerial seeds are smaller, more dormant, and more likely to be dispersed and form a seed bank than suberrranean seeds; (2) vegetative and reproductive growth of plants produced by aerial and subterranean seeds respond differently to light/shading; (3) when immature subterranean seeds were artificially exposed to an aboveground environment, they developed into aerial seeds, and vice versa. I conclude that production of aerial and subterranean seeds represents the optimal strategy in a wide variety of contexts by ensuring that at least some offspring can function appropriately in a variety of environmental conditions.