Photosynthesis occurs in green parts in leaves. Various types of tissues are present in the leaf, such as upper epidermis, lower epidermis, vascular tissues and mesophyll tissue. Mesophyll tissue again are of two types-compactly, arranged elongated cells at the upper epidermis are the palisade parenchyma tissue and loosely arranged cells at the lower epidermis is the spongy par-enchyma tissue. In plants, the chloroplasts are primarily located in the leaves. You can consider leaves to be photosynthetic organs. This is not true of all plants–think of a cactus, for example.
Usually photosynthesis occurs in palisade parenchyma cells of the leaf. Palisade parenchyma contains innumerous chloroplasts. The process of photosynthesis completed in these chloroplasts. The portion of palisade parenchyma in a dorsiventral leaf is shown in diagram.