Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 5 of 5
Full-Text Articles in Plant Sciences
Evidence Of Ecological Speciation In Phacelia., Pamela Michele Glass
Evidence Of Ecological Speciation In Phacelia., Pamela Michele Glass
Electronic Theses and Dissertations
Phacelia purshii Buckley and P. fimbriata Micheaux are two species that are nearly morphologically indistinguishable. Seed germination experiments showed that the high elevation endemic, P. fimbriata requires lower temperatures to trigger germination. Following interspecific crosses, pollen tubes enter ovules and maternal tissue of the gynoecium matures but hybrid diploid and triploid organs fail to develop. DNA sequences from the ribosomal DNA internal transcribed region showed that P. fimbriata and P. purshii comprise a monophyletic clade but that P. fimbriata is more differentiated from related species. In contrast, P. purshii supported significantly higher levels of intraspecific polymorphism. Phacelia fimbriata and P. …
Crop/Livestock Integration Effects On Soil Quality, Crop Production, And Soil Nitrogen Dynamics, Ellen B. Mallory
Crop/Livestock Integration Effects On Soil Quality, Crop Production, And Soil Nitrogen Dynamics, Ellen B. Mallory
Electronic Theses and Dissertations
Regional integration of potato and dairy farms has developed in Maine through arrangements where manure, feed, and sometimes land, are exchanged between neighboring farms. The effects of integration on soil quality, crop production, nitrogen (N) cycling, and N loss were investigated in field and laboratory studies of contrasting amended (manure, compost, green manure, and supplemental fertilizer) and nonamended (fertilizer only) soil management systems within 2-year potato (Solanum tuberosum L.) rotations in the Maine Potato Cropping Systems Project (MPEP). Additionally, soil quality of 48 integrated and nonintegrated Maine potato and dairy farm fields was assessed. The MPEP’s amended soil system enhanced …
Myriophyllum Heterophyllum Michx. (Haloragaceae): Control And Vegetative Reproduction In Southwestern Maine, Jacolyn E. Bailey
Myriophyllum Heterophyllum Michx. (Haloragaceae): Control And Vegetative Reproduction In Southwestern Maine, Jacolyn E. Bailey
Electronic Theses and Dissertations
Native to the southeastern United States, variable-leaf watermilfoil (Myriophyllum heterophyllum) is an invasive species in the Northeast and has been documented in Maine lakes for twenty years. Variable-leaf watermilfoil is targeted by the Maine Department of Environmental Protection as a species of grave concern as it has aggressively colonized twenty-six water bodies in Maine. This aquatic invasive plant grows in dense mats and outcompetes native vegetation. It is causing both ecological and economic disruption to Maine's lakes and ponds. The plants clog boat motors and deter people from swimming and other water related activities. Allofragmentation and autofragmentation occur …
Systematics Of The Lobulomycetales, A New Order Within The Chytridiomycota, David Rabern Simmons
Systematics Of The Lobulomycetales, A New Order Within The Chytridiomycota, David Rabern Simmons
Electronic Theses and Dissertations
Based on molecular phylogenetic analyses, the polyphyletic order Chytridiales, one of the four orders in the Chytridiomycota, contains several well-supported clades. One species, Chytriomyces angularis, however, does not group within the robust clades of the Chytridiales or any other chytrid order. The light-level morphology and zoospore ultrastructure of this aquatic species also differ from those of the type species of the genus Chytriomyces. I amassed nine additional pure culture isolates of soil-inhabiting chytrids with morphologies or rDNA sequences similar to C. angularis, including two isolates of C. poculatus, and studied the molecular phylogeny of these ten …
The Impact Of The Strawberry Bud Weevil (Anthonomus Signatus) On Raspberry (Rubus Idaeus) In Maine, Christina S. Howard
The Impact Of The Strawberry Bud Weevil (Anthonomus Signatus) On Raspberry (Rubus Idaeus) In Maine, Christina S. Howard
Electronic Theses and Dissertations
The response of red raspberry (Rubus idaeus) plants to the loss of flower buds through the feeding and oviposition activities of the strawberry bud weevil (Anthonomus signatus), and the potential impact of this bud loss on fruit yield and quality, was studied through greenhouse and field experiments. With two cultivars of raspberry (‘Killarney’ and ‘Encore’) grown in a greenhouse, manual clipping of flower buds to simulate strawberry bud weevil (SBW) damage demonstrated that the impact on yield is dependent upon the number of buds lost, their position on the inflorescence and cultivar. In a 2006 greenhouse study, removal of primary …