PHYSIOLOGISCHE UNTERSUCHUNGEN AN DER TROPISCHEN BASIDIOMYCETEN-FLECHTE CORA MONTANA (SW.) R. SANT.

Abstract

According to the hydratur of the atmosphere the basidiolichen Cora montana (Sw.) R. Sant increases and decreases its weight as shown in fig. 1. The relative transpiration is 100%. At an air temperature of 25° C the thallus of the lichen is in equilibrium with 85 % humidity. The maximum of the water content of the plant correspondes to 75-80%. The maximum of photosynthesis of more than 1 ml CCVh/g was readied in less than 1 hour in case of the thallus was allowed to swell in wet air (Fig. 2). In case the plant material was exposed to swell in water not only the maximum of photosynthesis was found to be less but also was readied in a longer period of time (Fig. 3). The longer the time of desiccation endured, the longer was the time the lichen needed to reach positive values of photosynthesis (Fig. 4). All maximum values of the photosynthetic ratio obtained correspond with those found in other lichens. A period of 3-4 month airdryness cannot be tolerated and afterwards no assimilation takes place. In other words, Cora montana is less adapted to desiccation than lichens of deserts. Exposed in dest. water Cora montana exudates substances, which increase the electric conductance considerably. The exosmosis of substances can be caused only partly by H ions because the equilibrium is reached already at a pH of 4.8.