Scholarship & Research

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Physiological traits and stress tolerances of three high-elevation pine species
(Montana State University - Bozeman, College of Letters & Science, 2023) Wasteneys, Chloe Elizabeth; Chairperson, Graduate Committee: Danielle Ulrich
The increasing frequency and intensity of drought and heat events are increasing forest mortality rates worldwide. To improve restoration and management effort effectiveness for at- risk tree species and to accurately predict how these species will respond to future climates, the physiological mechanisms of seedling establishment and survival need to be fully understood. Using a greenhouse common garden approach, we compared the physiological traits and stress tolerances of three high-elevation five-needle pine species, Pinus albicaulis (PIAL), P. flexilis (PIFL), and P. longaeva (PILO). We measured a suite of physiological response curves to determine photosynthetic capacity, high-light tolerance, drought tolerance, and heat tolerance traits. We compared these traits among the three species (Q1), among three different ages of PIAL seedlings (2-, 3-, and 5-years-old; Q2), and among seven families of 2-year-old PIAL originating from different locations (Q3). Among species (Q1), only one heat tolerance trait (Tcrit, the temperature at which minimal fluorescence begins to increase) significantly differed and increased from PILO to PIFL to PIAL, suggesting that PIAL had greater heat tolerance than PIFL and PILO. Among PIAL ages (Q2), two drought tolerance traits, saturated water content (SWC) and leaf mass per area (LMA), and two heat tolerance traits, Tcrit and T50_EL (temperature that results in a 50% increase in electrolyte leakage), significantly differed among ages. SWC decreased, LMA and Tcrit increased, and T50_EL partially increased with increasing age, suggesting that older PIAL seedlings may be more drought and heat tolerant than younger PIAL seedlings. Among PIAL families (Q3), no traits significantly differed. However, we observed four significant correlations between our measured traits and growing season mean temperature and vapor pressure deficit of the seven PIAL families. Families from relatively cooler, wetter locations tended to have greater high-light tolerance and greater heat tolerance (based on T50_EL) while families from relatively warmer, drier locations tended to have greater heat tolerances (based on Tcrit and T50 measured with chlorophyll fluorescence). Together, these findings improve our understanding of physiological mechanisms underlying seedling establishment and our ability to predict how these species may be affected by future climates.
Does the establishment of broadcast milkweed seeds versus containerized plugs differ in Willamette Valley restoration plots?
(Montana State University - Bozeman, College of Letters & Science, 2018) Tierney, Kelly Ann; Chairperson, Graduate Committee: Greg Francis
Monarch butterflies (Danaus plexippus plexippus) have been petitioned for conservation through listing under the Endangered Species Act. In the Willamette Valley, showy milkweed (Asclepias speciosa) acts as monarch natal and feeding ground habitat. Today, restoration ecologists are including showy milkweed in the suite of species used in prairie restoration projects to bolster the dwindling monarch populations. These biologists often started with including it as a portion of the seed mixes sown as part of a restoration. Later, many of these biologists switched to planting started, containerized plants (plugs) after failing to see much in the way of results from the previous seeding. This study focused on the establishment rate of containerized plugs versus broadcast seeding in restoration plots. Three prairie restoration sites were selected which had been seeded, then planted with plots of containerized plugs. Stems were counted at each site, both within the plug area, and at random across the rest of the site. Results from 2017 indicated planting plugs was more successful than broadcast seeding. However, the random sampling returned no plants and insufficient study design required a reexamination of the study sites in Summer 2018. My science advisor also recommended using the Focused (Intuitive Controlled) Survey method to collect sown milkweed instead to see if the results were different. The 2018 sampling yielded several individuals or clusters of milkweed in the sown sections. These were productive enough that we question which whether plugging milkweed is necessary.
Seedling vigor in birdsfoot trefoil
(Montana State University - Bozeman, 1963) Lin, Chuang-Sheng
Seed germination and seedling emergence in Amaranthus spp.
(Montana State University - Bozeman, College of Agriculture, 1985) Webb, David Morton
The effect of various soil amendments and preceding crops on seedling disease of sugar beets caused by Aphanomyces cochlioides Drechs
(Montana State University - Bozeman, College of Agriculture, 1949) Bellingham, Roscoe C.
The effect of seed weight on photosynthetic area development and weight of the sainfoin (Onebrychis spp. Scop.) seedling
(Montana State University - Bozeman, College of Agriculture, 1975) Fransen, Stephen Carl
The effect of the Russian wheat aphid on cold-hardiness of acclimating winter wheat seedlings
(Montana State University - Bozeman, College of Agriculture, 1991) Storlie, Eric William
Temperature and light effects on seedling performance of Pinus albicaulia
(Montana State University - Bozeman, College of Letters & Science, 1989) Jacobs, James Stuart
Relationship of endosperm exhaustion to growth and survival of orchardgrass seedlings (Dactylis glomerata L.) subjected to cold stress
(Montana State University - Bozeman, College of Agriculture, 1963) Murray, Glen A.
Ecotype variation in seedling and mature plant characteristics of basin wildrye (Elymus cinereus Scribn. and Merr.)
(Montana State University - Bozeman, College of Agriculture, 1963) Wilson, Roger Lavern

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