Weed ecological interactions with environment an investigation of temperature response of Commelina benghalensis and a method for description of seed shape /

by Sermons, Shannon Michelle.

SERMONS, SHANNON MICHELLE. Weed ecological interactions with environment: An investigation of temperature response of Commelina benghalensis and a method for description of seed shape. (Under the direction of Dr. Thomas Rufty and Dr. Michael Burton.) One of the most important challenges in agriculture is the threat posed by weeds. In recent years, the federal noxious weed Commelina benghalensis L. has become troublesome in Georgia and there are some indications that it is moving northward. Its tolerance of herbicides, including glyphosate, which is a primary management tool, as well as its reproductive elasticity are of particular concern. Temperature is an important determinant of plant range. Therefore, to help determine the potential for survival of C. benghalensis in North Carolina, a series of experiments examined its growth and reproduction over a range of temperatures. The results were then compared with historical temperature data and temperature responses of other weeds that grow and compete successfully in the North Carolina climate. These comparisons indicated that temperature would not pose a restraint to survival of C. benghalensis in North Carolina and further northward. In addition to these studies, a method was developed for describing seed shape. Seed characteristics can be affected by several factors and can have important impacts on germination and vigor of offspring. Although many studies have addressed seed characteristics, few quantitative tools exist for its study. The method that we have developed provides a more comprehensive, quantitative description of seed shape that can be utilized to evaluate reproductive characteristics of problem weed species.