Symbioses: Plant, Animal, and Microbe Interactions
Becklin, Katie , Galen, Candace .
The good, the bad, and the costly: Effects of shading and drought on the costs and benefits of mycorrhizae.
Mycorrhizal associations are a widespread mechanism for coping with soil resource limitation in plants. Because the costs and benefits of these plant-fungus mutualisms vary with environmental conditions such as light, water and nutrient availability, their relative importance to plant fitness should depend on the nature and degree of resource limitation. In this study we examined the independent and synergistic effects of mycorrhizal status, shading, and drought on the performance of the native alpine dandelion, Taraxacum ceratophorum, and its invasive congener, T. officinale. To test the effects of mycorrhizal status on plant performance we germinated seeds of each species in a potting mix with or without mycorrhizae. Once established, the seedlings were randomly assigned to one of four treatments in the greenhouse: shaded + wet, shaded + dry, open + wet, and open + dry. Plant size, photosynthetic rate (A), and instantaneous water-use efficiency (WUE) were measured for individuals in each treatment. Results indicate that mycorrhizae exacted a cost in plant size, balanced by a benefit in photosynthesis. Mycorrhizae also increased WUE, providing a potential benefit under open, dry conditions. Data suggest that mycorrhizae may be important to plants in dry habitats as long as light is not a limiting factor. Overall, our study demonstrates that the costs and benefits of mycorrhizal associations are context dependent, and that variation in mycorrhizal status can influence a plantís capacity to tolerate environmental stress.
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1 - University of Missouri-Columbia, Biological Sciences, 105 Tucker Hall, Columbia, Missouri, 65211, USA
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM