PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Plasticity traits in growth and defense expression among North American and European garlic mustard populations across moisture and nutrient gradients.
Hillstrom, Carl1, Cipollini, Don1, 1 Wright State University, Dayton, OH
ABSTRACT- Garlic mustard is a biennial Eurasian herb that has become invasive in North America. Many of its traits vary in response to its habitat, suggesting that adaptive changes may have contributed to its invasiveness. We examined whether phenotypic plasticity traits varied between populations and whether distinct plasticity traits have evolved among invasive (i.e. North American) populations. Plasticity was evaluated by examining interactive effects in a multifactorial univariate ANOVA on the number of rosette leaves, the length of the largest leaf, constitutive and jasmonic acid (JA) induced trypsin inhibitor (TI) and peroxidase (POD) activity, and chlorophyll fluorescence (Fv/Fm) on garlic mustard plants grown in a greenhouse, subject to a high or low water treatment and a high or low fertilizer treatment. The population, water, and nutrient factors interactively affected the number of leaves. European populations mostly had more leaves across the treatments, and there was an interactive effect between the water treatment and the continental origin on the number of leaves. All populations showed greater growth in response to the water treatment, but the difference was more pronounced among European populations. European populations also showed a greater length of the largest leaf after the water and nutrient treatments, but not before these treatments. The populations and the water treatments had an interactive effect on the POD activity, although each population responded very differently. The data from various chlorophyll fluorescence measurements showed different two-way interactions between the population and another factor affecting the Fv/Fm, but there was no consistency in how the populations were affected. Population, and in one case the continental origin, affected several chlorophyll fluorescence measurements. There is an interactive effect between the populations and JA on the TI activity, where TI activity increases in response to JA in all populations, but the amount by which TI is induced and the TI expression in non JA treated plants varies between populations. While there are clearly several differences in plasticity traits among the populations tested, it is questionable whether any plasticity traits can be clearly attributed to their continental origin.
Key words: garlic mustard, invasive species, phenotypic plasticity, Alliaria petiolata.