Japanese hops (Humulus japonicus) is an introduced species from eastern Asia whose current distribution extends over most of the eastern U.S.A. H. japonicus is capable of rapid growth and can form dense blankets of foliage. It's been observed that native species fare poorly in the presence of H. japonicus. A set of experiments were designed to test for the potential of H. japonicus to produce chemicals that may inhibit germination and growth in its competitors. A standard laboratory germination assay was preformed using extracts from foliar material of H. japonicus testing for inhibition in germination of 3 target species—Festuca rubra, Raphanus sativus, and Lactuca sativa. A field experiment using soils from areas colonized with H. japonicus and adjacent areas where hops was absent was preformed looking for and effect on germination and growth in silver maple (Acer saccharinum). Lastly a laboratory assay was designed using extracts obtained from soils, colonized with H. japonicus and without, investigating the potential for H. japonicus to promote its own germination. The results of the germination assay showed a consistent and significant delay in germination in all target species treated with H. japonicus foliar extract vs. controls. The field trial showed a significant delay in germination in A. saccharinum as well. Humulus japonicus also proved to promote its own germination in soils occupied by H. japonicus vs. controls. These results support the idea that H. japonicus may use allelopathic chemicals to delay or inhibit germination in native competitors while promoting its own success.
|Commitee:||Barry, Kelly, McCraken, Vance|
|School:||Southern Illinois University at Edwardsville|
|School Location:||United States -- Illinois|
|Source:||MAI 55/03M(E), Masters Abstracts International|
|Subjects:||Biology, Plant sciences|
|Keywords:||Allelopathy, Humulus japonicus, Invasive, Self facilitation|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be