NATIVE AND ATRAZINE-INDUCED FLUORESCENCE OF CHLOROPLASTS FROM PALISADE AND SPONGY PARENCHYMA OF BEECH (FAGUS-SYLVATICA L) LEAVES

Native and atrazine-induced fluorescence of chloroplasts from palisade and spongy parenchyma of european beech (Fagus sylvatica L.) leaves a re investigated by high-resolution laser-scanning microscopic imaging. and 3D-image processing software. The effects of light as environmenta l factor for leaf morphology (sunny and shade leaves) and atrazine as a D1-protein receptor blocker of the chloroplast-thylakoid antenna pro tein complex on chlorophyll fluorescence are studied by successive z-s cans (depth scan). Significant differences in chlorophyll fluorescence intensities of sunny and shade leaves are observed. The diffuse and n ondiffuse chlorophyll fluorescence of sunny leaf are higher than those of the shade leaf at each z-depth. Strong fluorescence of grana stack s from palisade parenchyma chloroplast due to atrazine treatment indic ates a high number of D1 protein binding sites at the grana stacks of palisade parenchyma chloroplast at each z-depth. It seems that a shutt erlike arrangement of D1-D2-Cytochrome b559-CP43-CP47 complexes exists , and apparently it regulates the light absorption, photosynthetic qua ntum conversion, and the fluorescence and protects the PSII antenna st ructures from thermal disturbances. As compared to chlorophyll fluores cence at atrazine bound sites, the generation of native chlorophyll fl uorescence is suggested to take place at other than D1-associated chlo rophyll protein complexes.