Abstract

Sunflowers are considered to be a part of a group of plants known as hyperaccumulators that share the ability to accumulate high amounts of heavy metals in the above ground organs, far in excess of the levels found in other species, often without suffering any phytotoxic effects. Quantifying the effects of zinc accumulation through the lens of the elemental defense hypothesis is essential for uncovering if there is a means to increase herbivore resistance in agricultural settings without the use of external interventions such as pesticides. A greenhouse study was conducted on four widely grown commercial cultivars of sunflower. Each cultivar was grown under multiple soil Zn concentrations ranging from 0 to 200 mg/kg of soil. Growth rate measurements were taken at evenly spaced intervals until maturity. Samples of leaves were taken from plants and tested for Zn concentration. A qualitative study using Vanessa cardui was conducted to observe the effects of zinc in the diet of caterpillars. Significant variation in the level of zinc accumulated in the leaves was observed as well as variation in overall biomass per treatment level. V. cardui experienced high rates of mortality at high zinc concentrations suggesting that further study may lead to significant evidence that Zinc accumulation is a form of herbivore resistance.

Thesis Completion

2019

Semester

Spring

Thesis Chair/Advisor

Mason, Chase

Degree

Bachelor of Science (B.S.)

College

College of Sciences

Department

Biology

Degree Program

Biology

Language

English

Access Status

Open Access

Release Date

5-1-2019

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Biology Commons

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