This is the tissue below the epidermis, and closest to the top of the leaf. It has the highest concentration of chloroplasts and performs maximum photosynthesis. Chloroplasts are concentrated particularly in the parenchyma cells of the leaf mesophyll. The inner stem cells and underground organs, such as the root system or bulb, contain no chloroplasts.
Why palisade tissue has more chloroplasts compared to other tissues?
The palisade mesophyll lies under the upper epidermis and above the spongy parenchyma in dicots. The palisade tissue has more chloroplasts compared to other tissues. This is the position of light reaction. The higher concentration of chloroplasts is the reason that the topmost surface of the leaf is darker compared to the lower surface.