dc.contributor.author	Morozov, Ivan Vladimirovitch	en
dc.contributor.committeechair	Foy, Chester L.	en
dc.contributor.committeemember	Westwood, James H.	en
dc.contributor.committeemember	Hagood, Edward Scott Jr.	en
dc.contributor.committeemember	Hagedorn, Charles III	en
dc.contributor.department	Plant Pathology, Physiology, and Weed Science	en
dc.date.accessioned	2014-03-14T21:23:50Z	en
dc.date.adate	1998-05-29	en
dc.date.available	2014-03-14T21:23:50Z	en
dc.date.issued	1998-05-13	en
dc.date.rdate	1999-05-29	en
dc.date.sdate	1998-05-13	en
dc.description.abstract	Broomrapes, <i>Orobanche</i> spp., are holoparasites that affect the growth of a variety of broadleaf crops. One of the distinct characteristics of the family Orobanchaceae is the lack of chlorophyll, and hence inability to synthesize their own food. Broomrapes subsist on the roots of the host plant from which they derive the carbon, water, and nutrients needed for further growth. Parasitism as such leads to yield reductions, and in case of heavy infestations, complete crop failure. Among other plants parasitized by broomrapes are several legumes, some of which are also the world's most economically important crops. As part of their unique biology, legumes provide an ecological niche for diazotropic soil bacteria, which belong to the family Rhizobiaceae. In return, the host plant receives fixed nitrogen from the nodules, specialized structures produced on the roots of most legume plants upon inoculation with bacteria. <i>Orobanche</i> spp. germination depends on the presence of chemical stimulant in host root exudates. It has been reported that inoculation of some legumes resulted in greater infestation by parasitic weeds. In addition, bacterial nodules were assumed to provide a place for broomrape invasion of host legume. Furthermore, infestations were observed to be more intense in aerobic conditions when rhizobia are most active. It is possible that production of the stimulant could be correlated with the infection of roots with <i>Rhizobium</i>, and that the nodules formed on the roots could play a role in broomrape parasitism; however, others have not confirmed this. Studies were conducted to investigate the possibility of interaction between <i>Orobanche</i> spp. attack and <i>Rhizobium</i> nodulation in legumes. Seed germination, number of parasitic attachments, as well as the morphology of two broomrape species, small broomrape (<i>Orobanche minor</i> Sm.) and Egyptian broomrape (<i>Orobanche aegyptiaca</i> Pers.), were studied. <i>O. minor</i> showed a greater percent seed germination, and formed a greater number of attachments on red clover (<i>Trifolium pratense</i> L.) inoculated with <i>Rhizobium leguminosarum</i> bv. <i>trifolii</i> in comparison with non-inoculated plants. However, the addition of the inoculum did not appear to enhance <i>O. aegyptiaca</i> seed germination or the number of its attachments on the host roots compared with the controls. Morphological observations of <i>O. minor</i> attachments on red clover suggest that parasitic attachments were not situated over the bacterial nodules, but perhaps involve parasite-induced enzymatic degradation followed by mechanical protrusion of host plant root cortex, possibly utilizing host plant-rhizobacteria interactions as well.	en
dc.description.degree	Master of Science	en
dc.identifier.other	etd-42998-142825	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-42998-142825/	en
dc.identifier.uri	http://hdl.handle.net/10919/40499	en
dc.language.iso	en	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	1Title.pdf	en
dc.relation.haspart	2Abstract.pdf	en
dc.relation.haspart	Chapter-1.pdf	en
dc.relation.haspart	Chapter-2.pdf	en
dc.relation.haspart	Chapter-3.pdf	en
dc.relation.haspart	Vita.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	Small broomrape	en
dc.subject	Orobanche minor Sm.	en
dc.subject	Egyptian broomrape	en
dc.subject	Orobanche aegyptiaca Pers.	en
dc.subject	red clover	en
dc.subject	nodulation	en
dc.subject	rhizobium	en
dc.title	Egyptian Broomrape (Orobanche aegyptiaca Pers.) and Small Broomrape (Orobanche minor Sm.) Parasitism of Red Clover (Trifolium pratense L.) in Vitro	en
dc.type	Thesis	en
thesis.degree.discipline	Plant Pathology, Physiology, and Weed Science	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en

Egyptian Broomrape (Orobanche aegyptiaca Pers.) and Small Broomrape (Orobanche minor Sm.) Parasitism of Red Clover (Trifolium pratense L.) in Vitro

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