Damage of PSII by Sulfite Sulfite Injure to Activity of PSII Particle and the Effect of Ca2+ Photoreduction of Cytochrome b559 in the Photosystem Ⅱ Reaction Center Complex Effect of copper stress on photosynthesis of navel orange seedlings EFFECTS OF Ca2+ ON PHOTOREDUCTION ACTIVITY OF ISOLATED CHLOROPLASTS AND RELATIONS TO CALMODULIN THE O2 AND NO2- PHOTOREDUCTION IN CHLOROPLASTS OF SUN AND SHADE LEAVES OF WOODY PLANTS