Physiological controls of Water-use and Nutrient-use efficiency in plants

 Water is a major plant growth-limiting factor and can often be the main cause of plant mortality. The interesting fact is that at a given plant water status, some plants will lose more water than others while photosynthesizing. Nutrients such as nitrogen and phosphorus play a pivotal role in controlling plant growth and development under varying water availability. The index of performance for each resource is simply calculated as the ratio of carbon gained per unit resource utilized. My life-long research goal is to understand how different plant species vary these indices at the biochemical level.

Currently, my lab is investigating the physiological and biochemical responses of agronomic and native endophytic grasses to drought stress.  We have found varying changes in stomatal conductance in response to drought in a single agronomic endophytic grass species (Festuca arundinaceae) that forms a symbiosis with an asexual fungus (Neotyphodium coenophialum). We have found that the endophytic plants exhibit changes in photosynthesis to a varying degree in response to drought stress. These physiological findings suggest that there must be biochemical changes that are mediated by the fungus under these conditions. We are interested in answering three questions over the next several years.

1. What are the main biochemical pathways that are upregulated by the fungus?

2. Which genes are being expressed in the presence of the fungus?

3. How generalized are these gene expression patterns among endophytic and non-endophytic grasses?

Research in my lab consists of the following activities:

1. You will learn how to read the primary literature carefully.
2. You will learn how to develop and test hypotheses about plant physiology and biochemistry.
3. You will learn how to write a research proposal.
4. You will learn how to use the CO₂ and H₂O gas analyzer correctly.
5. You will learn how to perform protein and enzyme assays.
6. You will learn about plant water relations.
7. You will learn how to make use of stable isotopes of carbon, nitrogen, oxygen and hydrogen to answer innovative research questions.
8. You will learn about gene expression analyses.
9. You will learn how to communicate scientific findings in the form of poster and oral presentations at regional and national meetings.

 Email me at swarthout@hope.edu if you are interested in working with me over the summer and during the semester.