Semester

Summer

Date of Graduation

2005

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Biology

Committee Chair

Richard B. Thomas.

Abstract

The purpose of this study was to determine the effects of increased temperatures associated with climate change on an understory medicinal herb, Panax quinquefolius. Three-year old P. quinquefolius were grown in a greenhouse at low (25°C day/20°C night) or elevated (30°C/25°C) temperatures for one growing season. Elevated temperatures decreased photosynthesis and accelerated leaf senescence. At the end of the growing season, biomass was detrimentally affected by increased temperatures; yet the concentration of root ginsenosides, secondary metabolites thought to be the primary pharmacological components, was higher in plants grown in the elevated temperature treatment than in plants grown in the low temperature treatment. Changes in the pharmacological activity of these extracted ginsenosides were determined by treating estrogen receptor-positive human breast cancer MCF-7 cells with known concentrations of total ginsenosides. Extracts from plants grown in the low temperature treatment were effective at lower concentrations and were overall more effective at decreasing the number of MCF-7 cells than extracts from plants in the elevated temperature treatment. This response was consistent for extracts harvested early and late in the season. Increased global air temperatures associated with climate change may have important implications for the ecology and pharmacological activity of sensitive understory herbs.

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