Life Sciences Commons^™

Sequencing Antisense Transcriptome Of Populus Through Antisense/Sense Transcript Pair Enrichment, Emma V. Burke

Dissertations, Master's Theses and Master's Reports

Past transcriptome research on plants focused primarily on protein coding genes, and only recently researchers began looking into the non-protein coding regions that may play significant roles in gene regulation. Antisense RNA transcripts that are found naturally in the cell share complementary sequence with sense transcripts and have been shown to regulate expression of their sense counterparts. Since antisense RNA has been largely under-studied and difficult to sequence because of their low relative abundance, new methods are needed to target antisense RNA for efficient genome-wide profiling. To address this gap in methods to efficiently and cost effectively enrich antisense RNA …

Changes In Poplar Digestibility Due To Overexpression Of Laccase Genes, Fnu Arunima

Dissertations, Master's Theses and Master's Reports

Woody biomass, particularly poplar, is a sought-after feedstock for lignocellulosic biofuels because of its year-round availability and high productivity. Because of cell wall components like lignin, poplar is inherently resistant to enzymatic saccharification. The experiment aims to determine whether the controlled overexpression of laccase genes alters the biomass composition and whether it can create poplar that is more digestible than the wildtype.

Three sets of transgenic poplar (Populus tremula x alba) samples were evaluated: laccase 18, laccase 27, and STTM. Laccase 18 samples, an target of miRNA397a was overexpressed along with Laccase 27. Short Tandem target Mimic (STTM) technology …

Common Garden Study Reveals Frost-Tolerant, Generalist Northern Seed Sources Are Best Suited To Expand Range Of Quercus Rubra, Emily Lindback

Dissertations, Master's Theses and Master's Reports

Climate change is shifting the potential suitable range of northern red oak (Quercus rubra L.) faster than it can migrate, creating an adaptation lag. Quercus rubra is prominent in eastern North American forests and important for its carbon sequestration, ecological roles, and economic significance. Our study addresses which populations of Q. rubra are best suited for climatic conditions at the northern and central range limits. Our findings can inform forestry management policies such as assisted migration, where species are transferred within their native range to mitigate the effects of climate change. We planted over 800 Q. rubra seedlings …

Application Of Short Tandem Target Mimic (Sttm) Technique For Functional Analysis Of Micro-Rna396 In Transgenic Poplar Trees, Surattana Boonsai

Dissertations, Master's Theses and Master's Reports

Short Tandem Target Mimic (STTM) is a commonly technique used for functional studies of a number of genes in several plant model systems. However, very little is known about application of STTM technique in tree species. In this study, STTM was applied to knock down microRNA396 (miR396) in transgenic poplar trees for the first time. STTM396 expression resulted in dramatic decrease in miR396 expression levels leading to taller plants with larger leaves and larger leaf cell size. Additionally, an expression analysis of growth regulating factor genes (GRFs) that are members of miR396 target gene family showed up-regulation of GRF07 gene …

Ecophysiological Responses Of Tropical Woody Species To Ambient And Elevated Temperatures, Kelsey R. Carter

Dissertations, Master's Theses and Master's Reports

Tropical forests cycle one third of Earth’s carbon, yet we are still unsure how tropical vegetation will respond to climate warming. Tropical biomes experience a smaller temperature margin compared to other systems, possibly making them less capable of thermal adjustments. In addition, thermal responses of vegetation have been identified as one of the areas of greatest uncertainty for global carbon models. This dissertation works to quantify tropical forest photosynthetic responses to temperature as well as assessing physiological thermal acclimation of four tropical species. In Chapter, 2 we conducted a meta-analysis to investigate global tropical photosynthetic responses to temperature. We presented …

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic and …

The Abiotic Stress Response Of Hydroponic Vetiver Grass (Chrysopogon Zizanioides L.) To Acid Mine Drainage And Its Potential For Environmental Remediation, Jef Kiiskila

Dissertations, Master's Theses and Master's Reports

Mining activities can generate acid mine drainage (AMD), an acidic discharge that contains elevated sulfate (SO₄^2-), soluble metals, and orange-yellow metal-containing particulates. AMD imposes ecological risks from metal toxicity and physical stress, which may physically spread to nearby water sources or biologically through bioaccumulation. Current methods for AMD treatment, such as chemical or passive biological treatments, are often non-sustainable. Chemical treatments can be expensive and create large amounts of secondary waste, whereas biological treatments like anaerobic wetlands require continuous maintenance through input of organic nutrients. The end goal of this research is to develop a cost-efficient and …

Effects Of In-Situ Leaf-Level Canopy Warming In A Northern Hardwood Forest, Kelsey Carter

Dissertations, Master's Theses and Master's Reports

Rising mean annual temperatures due to climate change have intensified the need to understand the effects of warming on plant physiological processes. Forest photosynthesis is the most important pathways of terrestrial carbon sequestration, yet continued warming could reduce this important carbon sink. Photosynthesis is highly sensitive to temperature and begins to decline after an optimum temperature (T_opt) is reached, leading to reduced carbon uptake. To date, logistical difficulties have limited our ability to test photosynthetic responses to sustained warming in mature forest canopies. In order to understand how elevated temperatures will affect forest ecosystems, we need to be …