Theses and Dissertations at Montana State University (MSU)
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Item Impacts of a non-native forb, Alyssum desertorum Stapf., and non-target effects of Indaziflam in the sagebrush steppe of Yellowstone National Park(Montana State University - Bozeman, College of Agriculture, 2021) Meyer-Morey, Jordan; Chairperson, Graduate Committee: Lisa J. RewNon-native plants can reduce biodiversity and disrupt essential ecosystem services and functions. For most non-native plant species however, quantitative evidence of negative effects is lacking, as are fundamental demographic details; such information can inform whether and at what growth stage to implement control. Control strategies can also negatively impact non-target native plant communities; therefore, evaluating the tradeoffs of management and understanding the actual impacts of the invader is essential. I sought to understand the life history, and evaluate the competitiveness and impacts of the non-native annual forb, Alyssum desertorum Stapf., as well as non-target effects of management, across an elevation gradient in a cool, mountain sagebrush (Artemisia tridentata ssp. vaseyana (Rydb.) Beetle) steppe plant community. Seed viability, fecundity, overwintering success, and likelihood of reaching reproductive maturity of A. desertorum all declined as elevation increased; all life stage transition rates were high, suggesting that targeting seed production or fall germination would be the most effective means for control of this species. Replacement series experiments revealed that A. desertorum is a weak competitor with functionally similar species. Additionally, in the field, the presence of A. desertorum did not affect species richness nor Shannon's diversity aboveground or in the soil seedbank, and functionally similar native annual forbs were not displaced in invaded areas. I evaluated the efficacy and non-target effects of the pre-emergent herbicide, indaziflam, in diverse sagebrush steppe with localized infestations of A. desertorum across an elevational gradient. While indaziflam effectively controlled A. desertorum for two years, the richness and diversity of the surrounding community was reduced. Indaziflam inhibited recruitment of forbs, both in the field and in the seedbank. As indaziflam provides residual control of the soil seedbank for up to three years, my results suggest the future community composition may be altered, particularly native annual forb populations. Considering the weak competitive ability of A. desertorum, the species' minimal impacts to richness and diversity, and the negative effects of indaziflam to annual native forb species, I conclude that the non-target effects of indaziflam would outweigh any benefits to controlling A. desertorum in intact sagebrush steppe.Item The Cruciferae of Montana(Montana State University - Bozeman, College of Agriculture, 1949) Clary, GeraldItem The fatty acid elongase of Physaria fendleri increases hydroxy fatty acid accumulation in transgenic Camelina(Montana State University - Bozeman, College of Agriculture, 2013) Snapp, Anna Rose; Chairperson, Graduate Committee: Chaofu LuPlant oils containing hydroxy fatty acids (HFA) are desirable for a wide variety of applications including lubricants, plasticizers, surfactants, polyesters, paints, sealants, biodiesel, and more. Due to unfavorable agronomic attributes of natural accumulators such as castor and lesquerella, many efforts have been made to produce hydroxyl fatty acids in crop plants. The hydroxy fatty acid synthesis pathway has been extensively studied and key genes such as the castor fatty acid hydroxylase, RcFAH, have been discovered. However, insertion of the RcFAH gene into various Arabidopsis backgrounds under the control of seed specific promoters failed to result in high accumulation of the desired HFA products, highlighting a need for more research to uncover additional constraints and factors affecting the fluxes involved with the accumulation of these unusual fatty acids in seed oil. In this study I investigated the effect of co-expressing a fatty acid elongase gene, LfKCS3, from Lesquerella (Physaria) fendleri along with the castor hydroxylase gene, RcFAH, on accumulation of hydroxyl fatty acids in seed oil of the crop plant Camelina sativa. On its own, wild type camelina contains no hydroxy fatty acids but insertion of the RcFAH gene results in accumulation of around 15% HFA in transgenic camelina, however, addition of the LfKCS3 gene resulted in a significant increase in very long chain 20-carbon hydroxyl fatty acids from <2% to 8%; total hydroxyl fatty acids also increased from 15% to 22% in the highest accumulating lines. The presence of the LfKCS3 enzyme effectively increased total HFA levels at all stages of oil accumulation in developing seeds while also decreasing the amount of these fatty acids left on the phospholipid, phosphatidylcholine. This combination of increased 20- carbon and total hydroxyl fatty acid accumulation along with the decreased HFA levels in phosphatidylcholine indicates that the LfKCS3 gene helps to enhance the flux of HFA out of phosphatidylcholine for incorporation of HFA into triacylglycerol, aiding in relief of the metabolic bottleneck for engineering economically viable levels of these fatty acids in oilseed crops.Item Consumer awareness and interest in Omega-3 fats and applications for marketing culinary camelina oil(Montana State University - Bozeman, College of Education, Health & Human Development, 2007) Weems, Tyson Victor; Chairperson, Graduate Committee: Alison HarmonCamelina sativa is a oilseed-bearing plant that grows in Montana and from which can be extracted oil containing 30-42% alpha-linolenic acid, an essential "omega-3" fatty acid. While researchers have associated certain health benefits with replacing other dietary fatty acids with alpha-linolenic acid and other omega-3 fatty acids, these are scarce in most Americans' diets. Current consumption levels are likely related to concurrent knowledge, beliefs, attitudes, and other behaviors about omega-3s and fat in general. The purpose of this study was to interview and survey likely targeted consumers to identify potential challenges and opportunities related to these factors for building interest and commitment to use culinary Camelina oil. Researchers intended results to facilitate determination of practical strategies for introducing Montana-produced Camelina oil as a viable commercial food product. Fifty athletes from the Greater Bozeman area ages 14-70 years participated in focus group discussions and sensory evaluation tests.