Plant Responses to
Environmental Stresses with Common Milkweed, Asclepias syriaca:
Tolerance and Resistance to Stress
How plants respond to
environmental stresses at mechanistic levels remains poorly
understood, and yet such understandings are crucial in resolving
ecological and evolutionary questions about plants and their
stressors. The experiments in this proposal involve common milkweed, Asclepias
syriaca, a chemically defended plant with low injury tolerance. In
the main stress response experiment, plants will be pre-exposed to 18
days of soil moisture and interference stress before receiving
simulated herbivory injury. I will collect data on leaf photosynthesis
measures (instantaneous rates and response curves) and gross cardiac
glycoside concentration. The results will test for interactions by
three environmental stressors in affecting A. syriaca leaf
physiology, and indicate whether a trade-off exists in plant capacity
for cardiac glycoside defense and tolerance to leaf injury. In sum, I
will determine whether A. syriaca has a general or multiple
specific responses to environmental stressors.
Kevin J. Delaney
208 Plant Industry
Dept. of Entomology
Univ. of Nebraska
Lincoln, NE 68583-0816
How plants respond to
environmental stresses at mechanistic levels remains poorly
understood, and yet such understandings are crucial in resolving
ecological and evolutionary questions about plants and their
stressors. The experiments in this proposal involve common milkweed, Asclepias
syriaca, a chemically defended plant with low injury tolerance. In
the main stress response experiment, plants will be pre-exposed to 18
days of soil moisture and interference stress before receiving
simulated herbivory injury. I will collect data on leaf photosynthesis
measures (instantaneous rates and response curves) and gross cardiac
glycoside concentration. The results will test for interactions by
three environmental stressors in affecting A. syriaca leaf
physiology, and indicate whether a trade-off exists in plant capacity
for cardiac glycoside defense and tolerance to leaf injury. In sum, I
will determine whether A. syriaca has a general or multiple
specific responses to environmental stressors.