Physiological and morphological responses of grass species to drought

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Show simple item record Bachle, Seton 2017-07-31T20:27:45Z 2017-07-31T20:27:45Z 2017-08-01 en_US
dc.description.abstract The impacts of climate change over the next 100 years on North American grasslands are unknown. Climate change is projected to increase rainfall and seasonal temperature variability, leading to increased frequency of drought and decreased rainfall amounts for many grassland locations in the central Great Plains of North America. To increase our ability to predict the effects of a changing climate, I measured multiple morphological and physiological responses from a diverse suite of C3 and C4 grasses. Due to varying characteristics associated with the different photosynthetic pathways, these grass species respond differently to altered temperature and precipitation. I monitored grass physiology and microanatomy in conjunction with varying watered availability to replicate drought. In the second chapter, I observed leaf-level physiology and root level morphology of C3 and C4 grasses when exposed to 100% water reduction. Results indicated that response to water reduction are not always dependent on the photosynthetic pathway. Root-level morphological measurements were found to vary significantly between species in the same genus; F. ovina had the highest specific root length (SRL), which is an indicator of tolerance to environmental variability. Results also indicated that grasses of interest have thresholds that when passed result in a photosynthetically inactive plant; however it was shown that they are able to recover to near pre-drought gas exchange rates when water is re-applied. The third chapter investigated both leaf-level physiology and morphology in dominant C4¬ grasses across Kansas’ rainfall gradient over the growing season. I hypothesized that variation within a species’ physiology would be greater than its’ morphology. I also hypothesized that morphology would predict variability in a species physiological response to changes in climate. This research discovered within a location and species, leaf morphology is fixed across the growing season. Strong correlations between leaf physiology and morphology were observed, however, the strength and relationship changed among the species compared. A. gerardii and P. virgatum exhibited opposing relationships when comparing their photosynthetic rates to the amount of bundle sheath cells. This result highlights strong species-specific relationship between physiology and morphology. My results illustrate the importance of utilizing plant physiology and morphology to understand how grasses may respond to future climate change scenarios. en_US
dc.description.sponsorship National Science Foundation Konza LTER Kansas State University en_US
dc.language.iso en_US en_US
dc.publisher Kansas State University en
dc.subject Ecophysiology en_US
dc.subject Grasslands en_US
dc.subject Climate change en_US
dc.subject Tallgrass prairie en_US
dc.subject Drought en_US
dc.subject Great Plains en_US
dc.title Physiological and morphological responses of grass species to drought en_US
dc.type Thesis en_US Master of Science en_US
dc.description.level Masters en_US
dc.description.department Department of Biology en_US
dc.description.advisor Jesse B. Nippert en_US 2017 en_US August en_US

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