In plants, the two layers that contain chloroplasts are primarily the mesophyll and the epidermis.
The mesophyll is located in the interior of the leaf and is divided into two sub-layers: the palisade mesophyll and the spongy mesophyll. The palisade mesophyll is where the majority of photosynthesis takes place, thanks to its tightly packed cells rich in chloroplasts that absorb sunlight efficiently. The spongy mesophyll, though less dense, also contains chloroplasts, allowing for some photosynthesis and facilitating gas exchange.
The epidermis, which is the outer layer of the plant, typically does not contain chloroplasts in most plants; however, in some cases, particularly in certain aquatic plants or in parts of the epidermis that form structures like guard cells, chloroplasts may be present. Still, the main site for chloroplasts is in the mesophyll layers located beneath the epidermis.
In summary, the two main areas where chloroplasts are found in plants are the palisade and spongy mesophyll layers, which are crucial for photosynthesis.