Enzymatic Characterization of the Membrane Fraction. The activities of marker enzymes associated with different organellar membranes were determined by spectrophotometric method. (A) Sodium azide-sensitive ATPase (mitochondrial membrane), (B) Potassium nitrate-sensitive ATPase (tonoplast), (C) Latent IDPase (Golgi membrane), and (D) K+-stimulated and sodium orthovanadate sensitive ATPase (plasma membrane). MF represents the membrane fraction, while CH represents the crude homogenate. All experiments were carried out in triplicates with at least two biological samples and average mean values were plotted against individual fractions.