Show simple item record

dc.contributor.advisorDavis, Arthur R.en_US
dc.creatorWist, Tyler Jonathanen_US
dc.date.accessioned2005-10-28T00:24:06Zen_US
dc.date.accessioned2013-01-04T05:07:05Z
dc.date.available2005-10-28T08:00:00Zen_US
dc.date.available2013-01-04T05:07:05Z
dc.date.created2005-10en_US
dc.date.issued2005-10-06en_US
dc.date.submittedOctober 2005en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-10282005-002406en_US
dc.description.abstractThe goals of this research project were to identify the various insects observed to visit inflorescences of Echinacea angustifolia DC, and to rank these visitors according to their importance as pollinators of E. angustifolia in Saskatchewan. Studying nectar and the nectary is essential to understanding the interaction of disc florets with pollinators. Nectar-sugar production by disc florets of E. angustifolia and E. purpurea (L. Moench) was quantified from anthesis to cessation with production per disc floret peaking in the afternoon of the staminate phase (191.7 µg) and at midday of the first day of the pistillate phase (156.6 µg), respectively. Morphology of the disc-like floral nectaries of both Echinacea species was studied, as well as the ultrastructure of the nectary of E. purpurea. Modified stomata on the nectary rim are the most likely exits for nectar, but creases in the epidermis may also participate. The nectary of E. purpurea is vascularized by phloem alone, which occurred adjacent to the epidermis. Companion cells possessed wall ingrowths, and these cells may unload arriving sugar destined for either an apoplastic or symplastic pathway. Lobed nuclei were a key feature of secretory parenchyma cells, as was a predominance of mitochondria, suggesting that energy-requiring eccrine secretion predominates in E. purpurea. E. angustifolia exhibited a generalist pollination system, with pollinating insects belonging to the orders Coleoptera, Diptera, Hymenoptera, and Lepidoptera. The pollination efficiency of visitors was determined by single insect visits to bagged, virgin inflorescences followed by quantifying pollen tubes at the bases of receptive styles and/or calculating the percentage of shrivelled styles. It was determined that bumble bees (Bombus spp.) were efficient pollinators, indicating that they would likely contribute much to the pollination of E. angustifolia. Grasshopper bee flies (Systoechus vulgaris Loew) were plentiful but individually were not efficient pollinators, but taken together, they provided much pollination. Golden blister beetles (Epicauta ferruginea Say) were efficient pollinators but where yellow-petalled flowers occurred, their numbers on E. angustifolia decreased. Honey bees (Apis mellifera L.) were efficient pollinators and were present in low numbers without managed introduction. Pierid (2003) butterflies were regular visitors and efficient pollinators, and likely contributed significantly to E. angustifolia pollination. When introduced, the alfalfa leafcutter bee (Megachile rotundata Fabr.) preferred not to forage on E. angustifolia and as such, these solitary bees were not suitable as managed pollinators. In large agricultural plantings of E. angustifolia, however, native insects may not be capable of providing sufficient pollination for seed production when floral competition occurs.en_US
dc.language.isoen_USen_US
dc.subjecthoney beeen_US
dc.subjectbumble bee (Bombus spp.)en_US
dc.subjectinsect cross-pollinationen_US
dc.subjectfloral morphologyen_US
dc.subjectnectary ultrastructureen_US
dc.subjectnectar dynamicsen_US
dc.subjectlight microscopyen_US
dc.subjectalfalfa leafcutter bee (Megachile rotundata)en_US
dc.subjecttransmission electron microscopyen_US
dc.subjectbreeding systemen_US
dc.subjectscanning electron microscopyen_US
dc.subjectEchinacea purpureaen_US
dc.subjectEchinacea angustifoliaen_US
dc.subjectseed productionen_US
dc.subjectshrivelled-style techniqueen_US
dc.subjectEpicauta ferrugineaen_US
dc.subjectSystoechus vulgarisen_US
dc.subjectgeneralist pollinationen_US
dc.subjectLepidopteraen_US
dc.subjectpollen-tube quantifyingen_US
dc.titlePollination biology of Echinacea angustifolia and E. purpurea (Asteraceae) in Saskatchewanen_US
thesis.degree.departmentBiologyen_US
thesis.degree.disciplineBiologyen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M.Sc.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberWilson, Kenneth E.en_US
dc.contributor.committeeMemberRichards, Kenen_US
dc.contributor.committeeMemberRandell, Roberten_US
dc.contributor.committeeMemberBarl, Brankaen_US


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record