Uncovering geospatial patterns of drought tolerance in Mimulus aurantiacus Nneka Nnatubeugo Bowdoin College University of Oregon – Summer Program for Undergraduate Research Mentor: Dr. James Sobel PI: Dr. Matthew Streisfeld Funded by the National Science Foundation

About Mimulus aurantiacus Red: marine influence: cooler, less seasonal, more days of cloud cover, less reason to be drought tolerant Yellow: seasonal, harsher, higher UV intensity, drier M. aurantiacus var puniceus M. aurantiacus var australis Reason for separation: ability to withstand drought? Or another combination of factors?

Research Question 1 Are there differences in drought tolerance between the ecotypes? Hypothesis: Yellow more drought tolerant than red or hybrid

Experimental Design Drought Tolerance 16 populations - 6 red, 4 hybrid, 6 yellow 189 maternal lines from populations 9-17 lines / population Transplanted three replicates from each line into cones – 567 total plants Grew and watered until differentiation then stopped watering Used qualitative scale to measure appearance of drought stress

Experimental Design Drought Tolerance 16 populations - 6 red, 4 hybrid, 6 yellow 189 maternal lines from populations 9-17 lines / population Transplanted three replicates from each line into cones – 567 total plants Grew and watered until differentiation then stopped watering Used qualitative scale to measure appearance of drought stress

p= Yellow ecotype is more drought tolerant than red ecotype dead Healthy

Yellow ecotype is more drought tolerant than red ecotype p= dead Healthy

Research Question 2 Which traits contribute to differences in drought tolerance? Leaf Area, Resin, Anthocyanin

Factors that affect drought tolerance

Experimental Design Resin & Anthocyanin Transplanted 2 plants per line into 2 ¾ inch pots Grown for 1.5 months and then sampled: Extracted resins and anthocyanin from leaves Analyzed concentrations of resin and anthocyanin via UV spectrophotometry Leaf Area Used program ImageJ to quantify

Red ecotype produces more anthocyanin than hybrid or yellow p=0.0105

Red ecotype produces more resin than hybrid or yellow p=0.0099

Red ecotype has greater leaf area than hybrid or yellow p=

Plants with greatest leaf area die fastest DAY 4DAY 5DAY 6 p=0.2838; R 2 = p<0.0001; R 2 =0.11p<0.0001; R 2 = dying alive

Yellow ecotype more drought tolerant than red ecotype The largest percent of variation in drought tolerance is explained by leaf area

Future Directions Measure vegetative anthocyanin and resin when the plants are stressed to see how the concentrations compare with the unstressed concentrations Measure drought and correct for the effect of leaf area in order to see how much of an impact ecotype has on the drought assessment

Acknowledgements Streisfeld Lab: Matt Streisfeld Jay Sobel Josh Bahr SPUR: Peter O’Day Adam Unger Fellow SPUR interns