Membrane permeability

In the present study physiological responses of three plant species (Boerhaavia diffusa L., Adhatoda vasica Nees and Parthenium hysterophorus L.) to hyperthermia have been investigated. Supra-optimal temperature was found to exert profound influence on stability of photosynthetic pigments, soluble proteins, membrane permeability and enzymes. The least decay in photosynthetic pigments was observed in Adhatoda while Parthenium was characterized by the maximum degradation of photosynthetic pigments. Treatment of leaves at high temperature also led to reduction in extractable aqueous buffer soluble proteins in all the plants. The membrane permeability under hyperthermia also differed markedly.
Apparent differences were observed among these plants with respect to thermostability of the enzymes. Peroxidase was found to be the most thermo tolerant enzyme in all the three plants studied. The enzyme PR of Adhatoda exhibited comparatively better thermotolerance than those of Boerhaavia and Parthenium.