The main pigments absorbing the light energy are chlorophyll and carotenoid in chloroplast of plant leaves. It seems nothing happens for the chlorophyll A (Chla) in the leaves of plants, even exposure in strong sunlight of summer. However photolysis occurred for the Chla resolved in the organic solution. In order to find the possible reason for this, several experimental investigations were made in this paper. According to the structure of Chla and β-carotene (β-Car) in the chloroplast, the chloroplast ...