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United States Department of Agriculture

Agricultural Research Service

Research Project: PRODUCTION, STABILIZATION AND FORMULATION OF MICROBIAL AGENTS AND THEIR NATURAL PRODUCTS

Location: Crop Bioprotection Research

Title: Captive bubble and sessile drop surface characterization of a submerged aquatic plant, Hydrilla verticillata

Authors
item Dunlap, Christopher
item Biresaw, Girma
item Shearer, Judy -

Submitted to: Current Topics in Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2012
Publication Date: November 15, 2012
Citation: Dunlap, C.A., Biresaw, G., Shearer, J.F. 2012. Captive bubble and sessile drop surface characterization of a submerged aquatic plant, Hydrilla verticillata. Current Topics in Phytochemistry. 11:53-58.

Interpretive Summary: This research determined the chemical and physical properties of the plant surfaces of the invasive aquatic weed, hydrilla. Hydrilla has been labeled as one of the world’s worst weeds and causes millions of dollars in ecological and economic damage in the U.S. each year by clogging waterways. This research utilized different techniques to characterize these properties of the weed. The knowledge of these parameters is needed to understand how weed control products will adhere to them. This is the first report of characterizing these properties for a submerged aquatic plant. These results will allow us to more effectively design new bioherbicide formulations to control the submerged weed. This research benefits scientists and the broad group of stakeholders looking for new hydrilla control options.

Technical Abstract: The surface energy parameters of the invasive aquatic weed, Hydrilla verticillata, were determined using contact angle measurements using two different methods. The abaxial and adaxial surfaces of the leaves and stem were characterized for the weed while submerged in water using captive air and octane bubbles. For comparison, the adaxial surface of air-dried leaves was characterized using sessile drops of three liquids. The results of captive bubble experiments estimate the surface energy parameters to be similar for each of the plant components with a surface free energy of ~45 dyn/cm with polar and dispersive contributions approximately equal. While air-dried leaf surfaces had an estimated surface free energy of ~47 dyn/cm with a dispersive component of 38 dyn/cm and a polar component of ~9 dyn/cm. These results highlight the need to take into account the hydration status of these types of surfaces when analyzing their surface energy components. This report is the first to characterize the surfaces of this important weed and submerged plant components.

Last Modified: 10/30/2014
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