Popis: |
1. 1.Three month-old seedlings of Taxodium distichum , Nyssa aquatica , Cephalanthus occidentalis and cuttings of Salix nigra were acclimated to simulated natural swamp conditions (ambient temperature, saturated soil) and then used to assess direct high temperature injury of root tissue. 2. 2.Electrolyte leakage from excised root tissue exposed for 30 min to temperatures ranging from 30 to 66°C was used to assess cellular injury. 3. 3.The relationship between leakage and temperature was sigmoidal for each species. 4. 4.Inflection point temperatures on the response curves, ranged from 45.4 to 51.0°C, were species-specific, and indicated differences in thermal tolerance of root membranes. 5. 5.Root of C. occidentalis and N. aquatica were more heat tolerant than roots of T. distichum and S. nigra . |