The changes of membrane permeability of mosses under high temperature stress

To assess the effects of high temperature stress on membrane permeability in mosses, we studied Plagiomnium acutum (Lindb.) T. Kop. and Thuidium cymbifolium (Doz. & Molk.) Doz. & Molk. in May and June 2001, using changes in conductivity measurements of the medium. The relative membrane permeability increased with the treatment duration within the range of 40-60degreesC. The higher the temperature, the more quickly the relative permeability increased. Regression curves indicate that the relationship between the relative percent permeability, and temperature are S-shaped and fit a logistic model. The 50% injury temperatures (IT50) are 44. 1 and 45.39degreesC, respectively.