Influence Of Seasonal Cues On Plant Interaction

Abstract

Phenotypic plasticity is the ability of an organism to express different phenotypes in response to environmental changes. A given genotype may change their morphology, physiology, developmental timing, and/or behavior in response to changes in biotic factors (e.g. presence/absence of neighbors) and/or abiotic factors (e.g. temperature). For example, the annual plant Arabidopsis thaliana responds to seasonal temperature cues by altering its flowering schedule. When seeds are cold treated (cold stratification, germinating after winter) plants flower earlier than if not (germinating before winter). They may also flower earlier if shaded by a neighbor. Plants rarely experience only one environmental factor and their plastic ability depends on their genotype. To test the hypothesis that plasticity to seed stratification influences plant interactions, I planted 3 inbred genotypes of A. thaliana with different flowering time responses to cold stratification in the center of a 3x3 grid (1.5 cm apart) with other plants (interaction) or with no surrounding plants (no interaction). To test if plants respond to differences in genotype of surrounding plants, they were planted in all possible inter- and intra-strain combinations. Replicates of interaction treatments were cold stratified or not and the center plant monitored for age at first flowering and number of fruits. To examine whole genome expression patterns in these environments, leaf tissues were harvested for hybridization to microarrays. We found that A. thaliana RILs are capable of recognizing neighbor genotypes but this ability was influenced by cold stratification of seeds. Additionally, A. thaliana RILs differentially expressed different genes in response to cold stratification of seeds and neighbor interaction.