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Articles 1 - 10 of 10
Full-Text Articles in Life Sciences
Diversity And Evolution Of Seeds In Cuscuta (Dodders, Convolvulaceae): Morphology And Structure, Magdalena Olszewski
Diversity And Evolution Of Seeds In Cuscuta (Dodders, Convolvulaceae): Morphology And Structure, Magdalena Olszewski
Theses and Dissertations (Comprehensive)
Cuscuta is a genus of nearly 200 obligate stem parasites with a nearly cosmopolitan distribution and considerable agricultural and ecological significance. Dodder seeds are considered “unspecialized”, with no morphological adaptations towards particular dispersal vectors; however, the seed coat anatomy has recently suggested an adaptation to endozoochory. This is the first attempt to provide a genus-wide overview of the diversity in morphology and anatomy of Cuscuta seeds, together with an assessment of the water gap and exploration of various form-function relationships. I surveyed 104 species belonging to all four Cuscuta subgenera. Seeds of the species of the first infrageneric dodder …
Diversity And Evolution Of Fruits In Cuscuta (Dodders; Convolvulaceae), Anna Ho
Diversity And Evolution Of Fruits In Cuscuta (Dodders; Convolvulaceae), Anna Ho
Theses and Dissertations (Comprehensive)
Cuscuta (dodder) is a genus of roughly 200 species of obligate stem parasites with sub-cosmopolitan distribution. The fruit, generally regarded as a capsule, has a thin pericarp containing one to four seeds and opening at the base (circumscissile dehiscence; DE), or remaining closed (indehiscent; IN). IN has evolved multiple times in Cuscuta from DE, and is most common in the North American clades of subgenus Grammica. In addition, some species produce fruits that open irregularly. Characteristics pertaining to the fruits of Cuscuta are important as their seeds contribute most to their distribution and prevalence across the globe, and their reduced …
Comparative Evolutionary Analysis Of Organellar Genomic Diversity In Green Plants, Weishu Fan
Comparative Evolutionary Analysis Of Organellar Genomic Diversity In Green Plants, Weishu Fan
Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research
The mitochondrial genome (mitogenome) and plastid genome (plastome) of plants vary immensely in genome size and gene content. They have also developed several eccentric features, such as the preference for horizontal gene transfer of mitochondrial genes, the reduction of the plastome in non-photosynthetic plants, and variable amounts of RNA editing affecting both genomes. Different organismal lifestyles can partially account for the highly diverse organellar genomes across the tree of green plants. For example, endosymbiotic and parasitic lifestyles can dramatically affect the genomic architectures of plant mitochondria and plastids. In this study, the organellar genomes of several green plants with atypical …
Chemically Mediated Interactions Between Hosts, Parasitic Plants And Insect Herbivores, Muvari C. Tjiurutue
Chemically Mediated Interactions Between Hosts, Parasitic Plants And Insect Herbivores, Muvari C. Tjiurutue
Doctoral Dissertations
Species interactions, by changing phenotypic traits, can alter the outcome of subsequent interactions. Plant-mediated responses to herbivores have been extensively studied, but little is known about plant-mediated responses involving parasitic plants within a broader community context that also includes herbivores. Because parasitic plants are important components of many ecosystems and can shape community structure, it is important to understand how host-mediated interactions influence parasite preference and success. The goal of this thesis is to examine interactions between hosts, parasitic plants and herbivores mediated by chemical traits. We first examined the effects of dodder (Cuscuta sp.) parasitism on induced defenses …
Cuscuta Jepsonii (Convolvulaceae): An Invasive Weed Or An Extinct Endemic?, Mihai Costea, Saša Stefanović
Cuscuta Jepsonii (Convolvulaceae): An Invasive Weed Or An Extinct Endemic?, Mihai Costea, Saša Stefanović
Biology Faculty Publications
Despite their ecological significance, parasitic plants face more conservation challenges than do autotrophic plants. This is especially true for the groups that include weedy or invasive species such as Cuscuta. While approximately half of the Cuscuta (dodders) species may require conservation measures, the genus as a whole is sometimes posted on governmental lists of noxious or quarantine weeds. Our study challenges this stereotype and uses the case of C. jepsonii (Jepson’s dodder) to illustrate the precarious biodiversity and conservation status faced by many dodder species. Until now, Jepson’s dodder has been known only from its type collection. Consequently, its …
Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin
Ecology And Molecular Phylogenetics Of Hydnora (Hydnoraceae) In Southern Africa, Jay Francis Bolin
Biological Sciences Theses & Dissertations
The Hydnoraceae are a clade of root holoparasitic angiosperms that contain two small genera, Hydnora and Prosopanche. This study, focused on Hydnora, presents novel data regarding the pollination biology, germination ecology, parasite-host nutritional relationships, and the molecular systematics of this group. Experimental addition of the primary pollinator, Dermestes maculatus to Hydnora africana chamber flowers demonstrated beetle imprisonment during the carpellate stage. Changes in the inner surfaces of the androecial chamber allowed beetle escape after pollen release. Most beetles escaped, dusted with viable pollen, three days after pollen release. To investigate germination ecology, aqueous root extracts of host and …
Structural Attributes Of The Hypogeous Holoparasite Hydnora Triceps Drège & Meyer (Hydnoraceae), Kushan U. Tennakoon, Jay F. Bolin, Lytton J. Musselman, Erika Maas
Structural Attributes Of The Hypogeous Holoparasite Hydnora Triceps Drège & Meyer (Hydnoraceae), Kushan U. Tennakoon, Jay F. Bolin, Lytton J. Musselman, Erika Maas
Biological Sciences Faculty Publications
The morphology of the hypogeous root holoparasite Hydnora triceps is highly reduced, and as with many holoparasites, the vegetative body is difficult to interpret. The vegetative body of H. triceps has been historically considered a "pilot root" studded with lateral appendages known as "haustorial roots." We found the vegetative body of H. triceps to consist of a rhizome with a thickened root-cap-like structure that covered a vegetative shoot apical meristem. From the apical meristem, procambial strands originated and developed into endarch collateral vascular bundles arranged radially around a pith without an interfascicular cambium. Xylem vessels had scalariform pitting and simple …
Delimitation Of Major Lineages Within Cuscuta Subgenus Grammica (Convolvulaceae) Using Plastid And Nuclear Dna Sequences, Saša Stefanović, Maria Kuzmina, Mihai Costea
Delimitation Of Major Lineages Within Cuscuta Subgenus Grammica (Convolvulaceae) Using Plastid And Nuclear Dna Sequences, Saša Stefanović, Maria Kuzmina, Mihai Costea
Biology Faculty Publications
Subgenus Grammica, the largest and most diverse group in the parasitic genus Cuscuta, includes ~130 species distributed primarily throughout the New World, with Mexico as its center of diversity. To circumscribe the subgenus ans assess the relationships among its major lineages, we conducted the first phylogenetic study of Grammica using plastid trnL F and nrITS sequences from a wide taxonomic sampling covering its morphological, physiological, and geographical diversiity. With the exception of of one species belonging elsewhere, the subgenus was found to be monophyletic. The results further indicate the presence of 15 well supported major clades within Grammica …
New Species Of Phoradendron (Viscaceae) From Mexico And Guatemala And A Synopsis Of Species In Section Pauciflorae, Delbert Wiens, Frank Hawksworth
New Species Of Phoradendron (Viscaceae) From Mexico And Guatemala And A Synopsis Of Species In Section Pauciflorae, Delbert Wiens, Frank Hawksworth
Aliso: A Journal of Systematic and Floristic Botany
As presently interpreted Phoradendron section Paucifiorae consists of 15 species. These mistletoes parasitize primarily conifers. We describe seven new species, make status changes for four species, and provide information on the hosts and distribution of all members of the section. New species described are: Phoradendron abietinurn Wiens, on Abies durangensi s in Chihuahua, Durango, and Jalisco, Mexico; P. acuminatum Wiens, on Cupressus lusitanica in Guatemala; P. flavomarginatum Wiens, on Juniperus fiaccida in Nuevo León, Mexico; P. lta wksworthii Wiens, on Juniperus in New Mexico, west Texas, and Coahuila, Mexico; P. olivae Wiens, on Cupressus lusitanica in Colima and Jalisco, Mexico; …
Dwarf Mistletoe Parasite In Spruce, F. H. Tainter, D. W. French
Dwarf Mistletoe Parasite In Spruce, F. H. Tainter, D. W. French
Journal of the Minnesota Academy of Science
Locations of all known major infection centers of dwarf mistletoe (Arceuthobium pusillum) in Minnesota are presented and compared to botanical ranges of important hosts. A brief summary of disease symptoms and identification of the parasite are included.