Ecological studies of Phoradendron serotinum (Raf.) M. C. Johnston, American Christmas mistletoe.
Item
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Title
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Ecological studies of Phoradendron serotinum (Raf.) M. C. Johnston, American Christmas mistletoe.
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Identifier
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AAI3103152
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identifier
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3103152
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Creator
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Opler, Annette Arcario.
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Contributor
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Adviser: Dwight Kincaid
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Date
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2003
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Botany | Biology, Ecology
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Abstract
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Mistletoe is the common name for approximately 1700 species of angiosperms, which share a common lifestyle. They are all parasitic or himiparasitic and most are found in the crowns of trees. The study species, Phoradendron serotinum (Raf.) M.C. Johnston is found in the southeastern United States. It grows on at least 58 different species of hosts. Birds disperse the seeds.;Field and laboratory studies were undertaken to gain insight into the role played by P. serotinum in the community. Field studies were performed at two sites in Williamsburg, Virginia. The two study sites were separated by almost 10 km. Further, there was a clear host preference for Gleditsia triacanthos at one site and for Carya cordiformis at the other site. The concentration of mistletoe is equal at both sites. At Carter's Grove there were 39.85 bushes/km2, and at Capital Landing Road, there were 44.81 bushes/km2. Analysis of variance showed no difference between the mistletoe concentration at these two sites (P = 0.84).;A series of laboratory bioassays demonstrated that P. serotinum produces secondary metabolites which exhibit anti-herbivore and allelopathic activities. The anti-herbivore activity was demonstrated against Spodoptera eridania, southern army worm, a voracious and formidable herbivore. The allelopathic activity was demonstrated using soil from the study sites.;In addition, the study species is high in anti-oxidants. It is established that free radical production increases with stress. All canopy residents are exposed to high levels of UV light and in addition mistletoe is subject to water stress when the upper canopy of the host develops low water potential. Therefore, production of phytochemicals capable of neutralizing free radicals is an attribute to be expected from a vulnerable canopy resident.;The production of these defensive phytochemicals by the study species led to prescreening of mistletoe for anti-cancer activity. Although all prescreening assays have yielded positive results, none of the active compounds have been isolated to date.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
