Title

Budgeting The Defense Efficiently: Effect Of Nutrient Deficiency And Insect Herbivory On Tannin Concentrations In Japanese Knotweed

Author(s)

David Strickland

School Name

South Carolina Governor's School for Science and Mathematics

Grade Level

12th Grade

Presentation Topic

Botany

Presentation Type

Mentored

Mentor

Mentor: Sara Topp, School of Agricultural, Forest, and Environmental Sciences, Clemson University

Abstract

Tannins are polymers of phenolic molecules produced by plants that can act as defense compounds by creating an unpalatable sensation and causing somatic damage to guts of insect herbivores. This study focused on delineating the ability of plants to produce tannins when faced with nutrient-sufficient vs nutrient-deficient environment; also we were interested in assessing the influence of herbivory on the tannin concentration within the above nutrient treatments. We analyzed the concentration of tannins in leaf tissues of Japanese knotweed (Fallopia japonica) that were grown under nitrogen deficient conditions (sugar added) and nitrogen sufficient condition (fertilizer added) from 2009 to 2013 . Green leaves with (10-20% loss of leaf area) and without herbivore damage were collected during June 2014, from plants grown at Musser Fruit Research Farm, Seneca, SC, that were exposed to nutrient treatments. Total tannin concentration did not vary with either nutrient treatment or herbivory. Despite similar total tannin content, the plants grown under nitrogen deficiency had a higher concentration of extractable tannins. The leaves with herbivore-damage had marginally higher fiber-bound tannins. We conclude that under lower soil nutrient levels knotweed produces more extractable tannins to protect the already acquired biomass, and mobility of extractable tannins within plants could enhance the defense capability of knotweed.

Start Date

4-11-2015 8:30 AM

End Date

4-11-2015 8:45 AM

COinS
 
Apr 11th, 8:30 AM Apr 11th, 8:45 AM

Budgeting The Defense Efficiently: Effect Of Nutrient Deficiency And Insect Herbivory On Tannin Concentrations In Japanese Knotweed

Tannins are polymers of phenolic molecules produced by plants that can act as defense compounds by creating an unpalatable sensation and causing somatic damage to guts of insect herbivores. This study focused on delineating the ability of plants to produce tannins when faced with nutrient-sufficient vs nutrient-deficient environment; also we were interested in assessing the influence of herbivory on the tannin concentration within the above nutrient treatments. We analyzed the concentration of tannins in leaf tissues of Japanese knotweed (Fallopia japonica) that were grown under nitrogen deficient conditions (sugar added) and nitrogen sufficient condition (fertilizer added) from 2009 to 2013 . Green leaves with (10-20% loss of leaf area) and without herbivore damage were collected during June 2014, from plants grown at Musser Fruit Research Farm, Seneca, SC, that were exposed to nutrient treatments. Total tannin concentration did not vary with either nutrient treatment or herbivory. Despite similar total tannin content, the plants grown under nitrogen deficiency had a higher concentration of extractable tannins. The leaves with herbivore-damage had marginally higher fiber-bound tannins. We conclude that under lower soil nutrient levels knotweed produces more extractable tannins to protect the already acquired biomass, and mobility of extractable tannins within plants could enhance the defense capability of knotweed.