Environmental Variability and Phenotypic Flexibility in Plants (Illinois)

The hypothesis is tested that genotypes within species or populations that have evolved in habitats with greater environmental variability will possess a greater ability to respond phenotypically to this variability than genotypes within species or populations that have evolved in habitats with less environmental variability. The phenotypic response quantified in this thesis is phenotypic flexibility, the growth advantage resulting from the phenotypic responses of traits. (1) The plasticity and acclimation of traits in the annual plant Abutilon theophrasti in response to growth in and transfer between growth light intensities was quantified by comparing the treatments at the same biomass. (2) The growth advantage attributable to plasticity in the two light environments was quantified by comparing the growth and assimilation of the high- and low-light phenotypes within each light environment. (3) Measurements of environmental variability (spatial and/or temporal variability in soil moisture; light intensity; leaf area index; transpiration, growth, and reproduction of plants, shading conditions experienced by individual plants) were made in old fields, tallgrass prairies, and deciduous forest floors in Illinois. The fields had the most, and the forest the least, variability in conditions as experienced by individuals and of the kinds likely to confer a growth advantage on phenotypic flexibility. (4) Twelve species of herbaceous perennials, four from each habitat, were raised in high and low light. Their phenotypic flexibility was estimated by two methods. Phenotypic flexibility was greater in the old field species group than in the prairie species group and greater in the prairie species group than in the forest species group, in agreement with the hypothesis.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Plant Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Rice, Stanley Arthur

• Biology, Ecology

Identifier

(UMI)AAI8711862

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/71285