Plant Phenotypic Expression in Variable Environments
Phenotypic expression is the result of a complex interplay between an organism’s genes and its environment.
During growth and development, organisms undergo a programmed series of phenotypic changes. Phenotypic expression thus varies throughout growth and development, even when the environment in homogenous and static. This has been termed “ontogenetic drift.”
Phenotypic expression may also vary with environmental conditions. The ability to vary phenotypic expression in response to environmental conditions is known as “phenotypic plasticity.”
The ability of an organism to express variable phenotypes in heterogeneous environments has been thought to confer adaptive benefits that increase fitness. Plants, as immobile organisms, cannot relocate to more favorable environments; plant phenotypic plasticity could be under strong selective pressure in predictably variable environments.
Plant growth rates and developmental trajectories are generally plastic; i.e., they frequently vary with local environmental conditions.
Whenever environmentally induced plasticity in growth and development occurs, interpretations of phenotypic plasticity are confounded with changes in phenotypic expression associated with ontogenetic drift.
Plant phenotypic plasticity should be evaluated in a developmentally explicit context. Phenotypic expression should be characterized in light of developmental trajectories of phenotypic change whenever possible.
Comparing plant phenotypes at a common age versus a common developmental stage may result in incorrect conclusions regarding the nature of the observed phenotypic variation.
Selection of methodological approaches to evaluate plant phenotypic expression should align with the hypothesis under investigation.
KeywordsPhenotypic Plasticity Phenotypic Expression Biomass Allocation Leaf Area Ratio Belowground Resource
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