Date of Award

2018

Document Type

Thesis

Degree Name

Bachelors

Department

Natural Sciences

First Advisor

Doan, Tiffany

Area of Concentration

General Studies

Abstract

Mimosa pudica (L.) utilizes a thigmonastic movement as a response to external stimuli. This response to mechanical perturbance if exposed repeatedly, results in a response reflective of habituation in animals. Recent research suggests this behavior in Mimosa pudica may be the primary defense against herbivory. The purpose of the current research is to determine if thigmonastic responses in plants like Mimosa pudica are influenced by changes in ecological variables like salinity, light, and temperature. Data were collected in the Summer of 2017 at the University of Louisville Kentucky. Plants were exposed to varying levels of soil salinity and exposed to a mechanical perturbance. Leaf width measurements were taken prior to mechanical perturbance, four minutes after mechanical perturbance, and upon reopening to the initial width prior to mechanical perturbance. Light levels were determined along with ambient temperature readings. Increases in soil salinity levels significantly negatively correlate with the speed at which Mimosa pudica leaves reopen, resulting in longer times remaining closed. Increases in both temperature and light significantly correlate to the rate at which M. pudica leaves reopen. Large increases in temperature additionally resulted in significantly smaller final leaf widths. Mimosa pudica is a global invasive found all across the tropics and subtropics. With increases in sea level and temperature due to climate change, the ability for Mimosa pudica to utilize this thigmonastic response for defence may be greatly hindered.

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