Record Details
Ecophysiology of the cyanolichen Lobaria oregana
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Ecophysiology of the cyanolichen Lobaria oregana |
| Names |
Antoine, Marie E.
(creator) Winner, William E. (advisor) |
| Date Issued | 2001-10-30 (iso8601) |
| Note | Graduation date: 2002 |
| Abstract | This thesis consists of three manuscripts describing ecophysiological research on the cyanolichen Lobaria oregana. The first manuscript includes a re-evaluation of the assumptions underlying past estimates of N fixation by this species and provides an estimate of annual N fixation at the Wind River Canopy Crane (WRCC). Based upon litterfall data, canopy biomass data, N content of lichen tissue, and published growth rates, L. oregana fixes 0.4-1.6 kg N₂ ha⁻¹ yr⁻¹. The second manuscript presents a series of physiological response curves and a model of N fixation by L. oregana. Temperature is the most important parameter controlling nitrogenase activity in hydrated thalli. The model is used to predict annual N fixation at the WRCC and at the H.J. Andrews (HJA) Experimental Forest. Lobaria oregana fixes 1.4-1.8 kg N₂ ha⁻¹ yr⁻¹ at the WRCC, and low winter temperatures often inhibit nitrogenase activity. Temperatures at the HJA are slightly warmer during the winter, and L. oregana fixes 2.6-16.5 kg N₂ ha⁻¹ yr⁻¹ depending on its stand-level biomass. The third manuscript investigates the effects of thallus water content, light, and temperature on CO₂ exchange in L. oregana. This species shows a typical photosynthetic response upon rehydration, and like other lichens it becomes light-saturated at low PAR levels. Positive net photosynthesis in L. oregana occurs only between 1-12°C. High respiration rates prevent carbon gain at warmer temperatures. The temperature constraints on carbon gain and nitrogen fixation may explain some of the landscape distribution patterns of L. oregana. |
| Genre | Thesis/Dissertation |
| Topic | Epiphytic lichens -- Ecophysiology |
| Identifier | http://hdl.handle.net/1957/29326 |
