Lange, OL/ Green, TGA/ Ziegler, H 1988: Water status related photosynthesis and carbon isotope discrimination in species of the lichen genus Pseudocyphellaria with green or blue-green photobionts and in photosymbiodemes. - Oecologia [Berlin]75: 494-501. [RLL List # 136 / Rec.# 11021] Keywords: PSEUDOCYPHELLARIA/ WATER RELATIONS/ PHOTOSYNTHESIS/ ISOTOPES/ PHOTOBIONTS/ PHOTOSYMBIODEMES
Abstract: 4 tables. 2 figures. ["Green lichens have been shown to attain positive net photosynthesis in the presence of water vapour while blue-green lichens require liquid water.... The behaviour is confirmed not only for species with differing photobionts in the genus Pseudocyphellaria but for green and blue-green photobionts in a single joined thallus (photosymbiodeme), with a single mycobiont, and also when adjacent as co-primary photobionts. The different response is therefore a property of the photobiont. It is proposed that the presence of sugar alcohols in green algae allow them to retain a liquid pool (concentrated solution) in their chloroplasts at low water potentials and even to reform it by water vapour uptake after being dried."]