Date of Award

Spring 2018

Document Type

Honors Thesis



First Advisor

Dr. Karen L. Koster

Second Advisor

Dr. Bernard M.W Wone

Third Advisor

Dr. David Swanson


Physcomitrella patens, respiration, desiccation, dehydration, relative humidity, oxygen consumption


The goal of this research was to test the effect of relative humidity on respiration and metabolism in the moss species Physcomitrella patens. Although this moss does not usually survive rapid desiccation, tolerance of extreme water loss can be induced by very slow drying and acclimation for 6-10 days at high relative humidity (RH). During acclimation, numerous changes in metabolite content occur, but metabolic rates during this process have not been measured. My goal was to determine how respiratory metabolism is affected during acclimation of the moss P. patens. I used a Hansatech oxygen electrode to measure O2 uptake by protonema samples of P. patens at full hydration and after varying times, up to 10 days, at 89% RH. The data suggest that respiration rates initially increased for up to 24 hours after the moss was transferred to 89% RH, then declined during the following days of acclimation. However, insufficient data were collected during this initial study to provide conclusive understanding of the effect of relative humidity on respiration in the moss Physcomitrella patens.



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