Abstract:
While previous experiments on the physiological activity of primary and secondary cyanolichens have been done, an analysis of photomorphs has never been attempted. Photomorphs of Peltigera britannica (Gyelnik) Hotan-Hartw. & Tonsberg were studied to compare the physiological response of a primary cyanolichen to an additional symbiotic partner (green algea) while keeping all species of partners (fungi and cyanobacteria) unchanged. Peltigera neopolydactyla (Gyelnik) Gyelnik was examined due to availability. Nitrogenase and photosynthetic activity were measured using the acetylene reduction assay and the Li-Cor 6400, respectively. Measurements were taken in the Willamette National Forest from January to May 2001. Peltigera britannica 2° Exhibited lower nitrogenase and slightly higher photosynthetic activity than both primary cyanolichens studied for most of the sample period. The May sampling was the first observation where P. britannica 2° exhibited higher nitrogenase activity than its primary photomorph. The May sampling also showed P. britannica 2° with twice the photosynthetic activity of both primary cyanolichens. The May sampling had the highest observed temperature (21 °C), while lichen water contents remained similar. Further investigation may show secondary cyanolichens remain more physiologically active at higher temperatures (with equal water contents) than primary cyanolichens, due to their additional green algal photosynthetic partner.
