The Phenology of Turion Formation in Spirodela polyrhiza as an Adaptation to Unpredictable Environments: Implications for the Evolution of Bet Hedging and Phenotypic Plasticity.

摘要

Reliable environmental cues may lead to the evolution of adaptive phenotypic plasticity. However, when cues are unreliable and the environment is thus unpredictable, "bet hedging" is expected to evolve. Here, the phenology of turion formation in (Spirodela polyrhiza (L.)) is used to study bet hedging and phenotypic plasticity in the field. Mean days to turion germination and formation were found to differ among pond environments-fronds from ponds of greater unpredictability had greater variability in the timing of turion formation. In a transplant study fronds behaved differently from when in their home environments, suggesting phenotypic plasticity in turion formation. In a common garden experiment, comparison of trait expression under homogenous conditions provided evidence for population differentiation. This study provides a test of putative diversification bet hedging, phenotypic plasticity and population differentiation in S. polyrhiza.