ce has become one of the most powerful methods for assessing photosynthetic performance in plant physiological experiments (Horton and Bowyer, 1990; Krause and Weis, 1991). This has resulted almost entirely from the development of methods to distinguish photochemical and nonphotochemical quenching of fluorescence. Moreover, it is now clear that the process of nonphotochemical quenching itself i...

The quenching of quinine fluorescence intensity in the presence of some anions in aqueous solution at ambient temperature has been investigated. The quenching is found to be collisional or dynamical in nature. This study reveals the order of two groups of quencher: NaI > NaBr > NaCl > NaF and K2Cr2O7 > KMnO4 >Na2SO4 > NaClO3. Increasing anion size in the both groups leads to an  increase in the...