Building a Better Biofuel: Discovering Physiological Differences Between Switchgrass Varieties

Abstract

As demand increases due to the non-renewable nature of the energy sources we use, fuel and energy are becoming ever more important to society in the USA. Renewable forms have risen in recent years such as ethanol made from corn grain. Although corn currently remains the number one feedstock for producing ethanol, the US Department of Energy is funding research on creating fuel from lignocellulosic plant material Switchgrass (Panicum virgatum L.) is a likely candidate for use in creating biofuel due to the wide array of environments it can survive in. as well as its productivity. There are several varieties of switchgrass however, and some produce more biomass than others in a given environment. By analyzing the physiological traits that may be responsible for the increased production of certain switchgrass varieties, it would be possible to select for these traits and maximize biomass output. This study analyzed twelve different switchgrass varieties (four lowland and eight upland ecotypes) grown in a common setting in order to identify differences in physiology. The different aspects of physiology that were measured included chlorophyll fluorescence in the form of non-photochemical quenching (NPQt) and photosystem II efficiency (Oil), xylem pressure, and root structure. During the night, NPQt and Oil were significantly different between ecotypes and varieties, indicating differences in their response to stress. Measurements for root structure and xylem pressure were not significantly different between varieties or ecotypes. These data suggest that there are minimal differences in water use. physiology and root structure among these twelve varieties, at least in the environment conducted. Future work will continue to look at these traits and others to determine which are most responsible for differences in biomass production.