Basidiomycete Responses To Moisture

Opening of a forest canopy by natural or anthropogenic disturbance causes dramatic environmental changes on the forest floor. Following canopy damage in Puerto Rico caused by Hurricane Hugo, the litter layer experienced more rapid drying as a result of greater exposure to solar irradiation and wind (Lodge et al., 1991, 1994), resulting on ridges in higher mortality of Collybia johnstonii — a species that forms superficial mycelial fans on leaf surfaces, and was the dominant litter fungus in tabonuco forest prior to the hurricane (Lodge and Cantrell, 1995; Lodge, 1996). Higher stress tolerance of some marasmioid species allowed them to replace C. johnstonii on ridges (Lodge and Cantrell, 1995).

Effect of moisture on attachment rate of litter by mycelial mats of Micromphale brevipes, Marasmius guyanensis (both terrestrial species), Marasmius crinis-equi and Micromphale sp. (both aerial species), from Luquillo Experimental Forest, was studied by dividing mats and placing them in separate baskets (18 cm x 25 cm, with mesh bottoms) and placing in either shade or partial shade, moistened with 2 l of stream water on alternate days (except on rainy days), and resupplied with litter weekly. Evaporation potential was measured in the mat source environments, and the shade and partial shade propagation areas (using 3 ml vials of distilled water into which a 2 mm diameter cotton wick was inserted with 5 mm of the wick exposed to the air). Mean evaporation potentials were higher in partial (2.5 mm week-1) than in full shade (0.75 mm week-1). There were significant (P = 0.009) differences in attachment rates among species; M. crinis-equi formed significantly more attachments than the other species (Figure 6). Differences between attachment rates were not significant between light environments (P = 0.548), though two of the four species had better attachment rates in full shade, but M. brevipes had better development in partial shade (Figure 5). M. brevipes also had the driest source environment.

0 0

Post a comment