Life Sciences Commons^™

Changes In The Barley Stem Proteome In Response To Drought During Grain Filling, Mohammed Al Slamh

Dissertations and Theses @ UNI

Drought is the major environmental factor that limits crop yield worldwide. Crops are particularly vulnerable to drought at the reproductive stage. In cereals, grain filling during drought depends on the contribution of current photosynthesis products from the leaf and spike and carbohydrates stored mainly in the stem and remobilized to the grain. Even though stem reserve is an important source for grain filling, changes in the proteome of barley stem under drought have not been studied. Also, the molecular events associated with differential stem reserve remobilization under drought are not well understood. In this study, barley plants were exposed to …

Community Diversity Influences Selection On Nutrient Resorption In Panicum Virgatum, Michael J. Lashbrook

Dissertations and Theses @ UNI

Panicum virgatum L. (switchgrass) is a bioenergy crop shown to conserve and recycle nutrients through a process known as nutrient resorption. While there are many studies looking at various aspects of nutrient cycling in switchgrass, it remains unclear whether selection is acting upon increased nutrient resorption in this species. Further, there are no phenotypic selection studies coupling empirical sexual and asexual reproduction data.

A field study and a modeling study were conducted to determine phenotypic selection on nutrient resorption and the influence of resorption on asexual reproduction in switchgrass. For the field study of phenotypic selection, I hypothesized selection favors …

The Effect Of Cold Stratification And Perigynia Removal On The Germination Of Three Prairie Carex Species, Christina M. Boeck Crew

Dissertations and Theses @ UNI

Sedges (Carex spp. Linneaus. [Cyperaceae]) are a major component of Midwestern U.S. tallgrass prairie and prairie wetland plant communities, yet they are often lacking in restoration projects because they can be difficult to germinate. Cold-wet stratification and perigynia removal have been shown to increase germination in some Carex species. The germination response of 3 native species, plains oval or shortbeak sedge (C. brevior (Dewey) Mack.), field oval or troublesome sedge (C. molesta Mack.), and prairie or Bicknell’s sedge (C. bicknellii Britton.), was tested to cold-wet stratification (28d) and perigynia removal in stored seed (10 months). Seed treatments …

The Effects Of Nutrient Resorption, Photosynthetic Rate, And Leaf Longevity On The Success Of Typha × Glauca, Clarissa Marie Ruiz

Dissertations and Theses @ UNI

The hybrid cattail Typha × glauca is invasive in the Midwestern United States, and outcompetes wetland natives and its parent species, Typha angustifolia and Typha latifolia under high nutrient conditions. Typha × glauca’s large size and copious litter production are the main factors known to contribute to its success, although research is lacking on physiological processes that contribute to its nitrogen use efficiency.

Nitrogen resorption was investigated as a mechanism of dominance in Typha × glauca. Due to nitrogen resorption being a nutrient conservation strategy, nitrogen resorption should be high in areas of low nitrogen availability. Since nitrogen …

The Effects Of Mycorrhizal Inoculant And Micronutrients On Early Plant Establshment During A Tallgrass Prairie Reconstruction, Christopher L. Barber

Dissertations and Theses @ UNI

Symbiotic relationships between mycorrhizal fungi and land plants are one of the most widespread examples of symbiosis on Earth yet there is still much to discover about their ecological impacts.

Prairie reconstructions are often done on highly disturbed sites such as reclaimed cropland, turf grass, and road rights-of-way. Disturbed soils often lack adequate quantities of both mycorrhizal fungi and micronutrients. I hypothesized that inoculated seeds with mycorrhizal spores or micronutrient seed treatments will aid in the early establishment of a tallgrass prairie.

To test this hypothesis four treatments (T1 control, T2 mycorrhizal, T3 micronutrient, and T4 mycorrhizal and micronutrient) were …

Development Of Leaf Shape And Vein Homologies In Five Species Of The Genus Ipomoea (Convolvulaceae), Austin William Jones

Dissertations and Theses @ UNI

Angiosperm leaves are extremely variable in form while predominantly maintaining the function of the primary photosynthetic organ of the plant. Changes in leaf form can result from myriad physiological processes which may be influenced by ecology, physical stimuli, phylogeny, or other factors. In studying the development of divergent leaf forms among closely related species, conserved morphological elements may be identified that are not apparent in the mature form. The genus Ipomoea (Convolvulaceae) contains over 600 species and a wide range in leaf shapes. Five species, I. purpurea, I. coccinea, I. sloteri, I. quamoclit, and I. cairica show a range in …

Tracking Above- And Below- Ground Seed Persistence And Mortality In A Native Tallgrass Prairie Restoration, Carmen Pellish

Dissertations and Theses @ UNI

The large cost of seed and low seedling establishment rates make restoring native tallgrass prairies expensive and difficult. Tallgrass prairie restorations typically achieve seedling emergence rates of only 10%. This begs the question of what happens to the remaining 90% of seeds that do not emerge as seedlings. This thesis sought to assess or quantify the importance of seed predators and death by microorganisms or to senescence on seed survival and seedling establishment within a newly planted native tallgrass prairie restoration under typical restoration conditions. I hypothesized that small vertebrate seed predators would play be detrimental to overall seedling emergence …