Date of Defense

Spring 4-16-1996


Biological Sciences

First Advisor

Stephen Malcolm, Biological Sciences

Second Advisor

Alexander Enyedi, Biological Sciences

Third Advisor

Barbara Cockrell




Under what conditions a plant chooses whether to grow or defend itself are unknown. By applying stressors to well understood plants and ecological interactions, we can begin to address these questions. The experiment I carried out elucidated the effects of cadmium, a possible stressor, on milkweeds. Background was provided for each of the players in the interactions. Latex was collected and analysed for cardenolide, and root, shoot and leaf dry biomass weights were taken. It was found cadmium acts as a stressor up to an undetermined threshold between treatments of 50 µMolar and 500 µMolar Cd++ concentrations, then acts as a growth stimulator from that point to a possible second point where it will lead to the plant's death. Cardenolide levels showed no significant difference among treatments. Together, these findings give some indication that under the regimes imposed by high levels of Cd++, milkweeds would preferentially shunt resources to secondary metabolism, therefore to defend itself primarily.

Access Setting

Honors Thesis-Campus Only