For over a century, documented scientific research and debate has revolved around the therapeutic properties of the medicinal plant Echinacea angustifolia. With overwhelming evidence demonstrating the biological activity of its root phytochemical constituents, the genetic improvement of E. angustifolia by selecting phytochemically rich genotypes has garnered both scientific and commercial interest. This dissertation presents results of multi-disciplinary experiments intended to help establish scientifically based guidelines for breeding efforts aimed at developing therapeutically superior varieties of E. angustifolia in British Columbia. Cultivated E. angustifolia populations from British Columbia and Washington were grown in a common greenhouse environment to identify possible genetically superior populations with respect to root concentrations of therapeutically relevant caffeic acid derivatives (CAD) and alkamides. However, none of the studied cultivated E. angustifolia populations showed significant genetic differences in terms of root phytochemical traits. In the second part, an investigation into correlations between root and shoot phytochemical concentrations in field- and greenhouse-grown plants revealed that concentrations of therapeutically relevant marker compounds in shoots were generally poor predictors of concentrations in roots. Some weak yet significant positive correlations were observed between root and shoot concentrations of CADs but were inconsistent between the two environments. Significant genotype by environment interactions were documented for the first time in phytochemical traits of E. angustifolia in a study of five genetically homogeneous populations grown in three different environments, including 1 greenhouse and 2 field sites in British Columbia. For the final objective, in vitro bioassays showed that environmentally and genotypically related differences in concentrations of CADs and alkamides in E. angustifolia ethanolic root extracts did not translate into significant differences in their anti-inflammatory potential as measured by pro-inflammatory interleukin (IL-6 and IL-8) secretion in human bronchial epithelial (BEAS-2B) cells challenged with rhinovirus. When used in isolation however, pure tetraene alkamide showed a significant inhibitory effect on secretion, thereby further supporting the use of high alkamide production as a selection criterion for therapeutic E. angustifolia cultivar development. A series of recommendations derived from these findings are presented along with ideas for important future studies in the field of Echinacea research.

For over a century, documented scientific research and debate has revolved around the therapeutic properties of the medicinal plant Echinacea angustifolia. With overwhelming evidence demonstrating the biological activity of its root phytochemical constituents, the genetic improvement of E. angustifolia by selecting phytochemically rich genotypes has garnered both scientific and commercial interest. This dissertation presents results of multi-disciplinary experiments intended to help establish scientifically based guidelines for breeding efforts aimed at developing therapeutically superior varieties of E. angustifolia in British Columbia. Cultivated E. angustifolia populations from British Columbia and Washington were grown in a common greenhouse environment to identify possible genetically superior populations with respect to root concentrations of therapeutically relevant caffeic acid derivatives (CAD) and alkamides. However, none of the studied cultivated E. angustifolia populations showed significant genetic differences in terms of root phytochemical traits. In the second part, an investigation into correlations between root and shoot phytochemical concentrations in field- and greenhouse-grown plants revealed that concentrations of therapeutically relevant marker compounds in shoots were generally poor predictors of concentrations in roots. Some weak yet significant positive correlations were observed between root and shoot concentrations of CADs but were inconsistent between the two environments. Significant genotype by environment interactions were documented for the first time in phytochemical traits of E. angustifolia in a study of five genetically homogeneous populations grown in three different environments, including 1 greenhouse and 2 field sites in British Columbia. For the final objective, in vitro bioassays showed that environmentally and genotypically related differences in concentrations of CADs and alkamides in E. angustifolia ethanolic root extracts did not translate into significant differences in their anti-inflammatory potential as measured by pro-inflammatory interleukin (IL-6 and IL-8) secretion in human bronchial epithelial (BEAS-2B) cells challenged with rhinovirus. When used in isolation however, pure tetraene alkamide showed a significant inhibitory effect on secretion, thereby further supporting the use of high alkamide production as a selection criterion for therapeutic E. angustifolia cultivar development. A series of recommendations derived from these findings are presented along with ideas for important future studies in the field of Echinacea research.

For over a century, documented scientific research and debate has revolved around the therapeutic properties of the medicinal plant Echinacea angustifolia. With overwhelming evidence demonstrating the biological activity of its root phytochemical constituents, the genetic improvement of E. angustifolia by selecting phytochemically rich genotypes has garnered both scientific and commercial interest. This dissertation presents results of multi-disciplinary experiments intended to help establish scientifically based guidelines for breeding efforts aimed at developing therapeutically superior varieties of E. angustifolia in British Columbia. Cultivated E. angustifolia populations from British Columbia and Washington were grown in a common greenhouse environment to identify possible genetically superior populations with respect to root concentrations of therapeutically relevant caffeic acid derivatives (CAD) and alkamides. However, none of the studied cultivated E. angustifolia populations showed significant genetic differences in terms of root phytochemical traits. In the second part, an investigation into correlations between root and shoot phytochemical concentrations in field- and greenhouse-grown plants revealed that concentrations of therapeutically relevant marker compounds in shoots were generally poor predictors of concentrations in roots. Some weak yet significant positive correlations were observed between root and shoot concentrations of CADs but were inconsistent between the two environments. Significant genotype by environment interactions were documented for the first time in phytochemical traits of E. angustifolia in a study of five genetically homogeneous populations grown in three different environments, including 1 greenhouse and 2 field sites in British Columbia. For the final objective, in vitro bioassays showed that environmentally and genotypically related differences in concentrations of CADs and alkamides in E. angustifolia ethanolic root extracts did not translate into significant differences in their anti-inflammatory potential as measured by pro-inflammatory interleukin (IL-6 and IL-8) secretion in human bronchial epithelial (BEAS-2B) cells challenged with rhinovirus. When used in isolation however, pure tetraene alkamide showed a significant inhibitory effect on secretion, thereby further supporting the use of high alkamide production as a selection criterion for therapeutic E. angustifolia cultivar development. A series of recommendations derived from these findings are presented along with ideas for important future studies in the field of Echinacea research. / Land and Food Systems, Faculty of / Graduate

The 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.

The 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.