Date of Award

Fall 2019

Document Type

Thesis Restricted

Degree Name

Master of Science (MS)

Department

Biology

Committee Chairperson

Gregory Turner, Ph.D.

Committee Member

Jennifer Chandler, Ph.D.

Committee Member

Harry Tiebout, Ph.D.

Abstract

Invasive plant species are one of the most prominent threats to Eastern deciduous forests. One such species, Lonicera maackii, is a shrub that exhibits allelopathic effects in microhabitats immediately surrounding the plant. A native plant, Lindera benzoin, similarly employs this competitive inhibition mechanism. Few studies have made comparisons between exotic and native allelopathic shrubs in Eastern United States deciduous forests. The allelopathic effects of these plants were compared in field, and in laboratory and greenhouse studies. In the field, woody and herbaceous plants were censused beneath both shrub species at three different sites, and a number of potentially influential abiotic factors were also quantified. In the greenhouse, Quercus stellata seedlings were treated with high and low exudate concentrations prepared from L. benzoin and L. maackii. After a period of growth, the Q. stellata specimens were processed and secondary growth variables, such as first order root numbers, were quantified. A germination study was conducted using Ulmus americana seeds with the same exudates and concentrations as those used in the greenhouse study. Analyses of these studies determined that exudates from L. maackii and L. benzoin have effects on Q. stellata root growth and U. americana germination. Given the overall results of these studies, it is possible to suggest that allelopathy, whether from exotic invasive or native shrubs, may influence plant growth and seed germination in the Eastern deciduous forest, and therefore composition and biodiversity.

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