The photosynthesis of azalea exhibited a midday depression on bright sunny days in the end of spring under field conditions. The Pn increased rapidly in a few hours after sunrise, reached the first peak at about 10:30 A.M., followed by a marked decease untill about 2:10 P.M., then increased again and reached the second lower peak at about 3-00P. M. Shading the leaves by the shadow of willow tree or by the cover of gauze with 50-34% of Light intensity of natural light, no midday depression was found. The pat...