XVI International Botanical Congess

The development of alpine tundra species is characterized by extreme preformation: leaves and inflorescences are initiated as many as three years prior to maturation and function. Such protracted periods of development are predicted to delay, or preclude, morphological responses to environmental variation. Yet, the capacity for phenotypic response is likely to be critical in the highly variable alpine environment. Are alpine plants phenotypically plastic? Developmental and experimental analyses demonstrate that plasticity of vegetative traits is constrained within but not among years. Plasticity of reproductive traits occurs both within and among years through over-initiation and abortion. Development of alpine perennials is plastic, yet due to preformation, there is a delay in the morphological (and potentially the functional) expression of plasticity.