Final answer:
The cylindrical shape of palisade mesophyll cells increases photosynthesis in leaves by maximizing light absorption, ensuring close proximity to carbon dioxide, and favoring efficient transport of photosynthetic products due to their large surface area and tight packing.
Step-by-step explanation:
The cylindrical shape of the palisade mesophyll cells in plant leaves plays a crucial role in maximizing photosynthesis. These cells, arranged tightly together, are columnar in structure and packed with chloroplasts, the organelles responsible for capturing light energy. The cylindrical form allows for a large surface area relative to the volume of the cell, which in turn increases the amount of light that the chloroplasts can absorb. This structural adaptation is critical because more light absorption equates to more energy for the photosynthesis process.
In addition to light absorption, the tight packing of the palisade mesophyll cells ensures that carbon dioxide, necessary for photosynthesis, is readily available to all the chloroplasts. The proximity of these cells to the surface of the leaf minimizes the distance that carbon dioxide must diffuse from the stomata (where gas exchange occurs) to the chloroplasts. Furthermore, the vertical orientation of these cells helps facilitate efficient gas exchange as well as the transport of sugars and other photosynthetic products to other parts of the plant.
Lastly, the spongy mesophyll, located below the palisade layer, has irregularly shaped cells with air spaces that also allow for gas exchange and distribution. However, the palisade mesophyll's cylindrical shape is specialized to optimize light interception and the photosynthetic process, making them the primary site of photosynthesis in most dicot leaves.