The cuticle is the waxy, non-living surface of the leaf that traps water inside. The outer layer, or epidermis, is one cell thick and protects the most important parts of the leaf. The mesophyll or middle tissue layer is made up of several components, including palisade cells that serve as the primary site of photosynthesis. Palisade cells are elongated and perpendicular to the surface of the leaf in order to maximize photosynthetic output by maintaining greater access to sunlight. Sometimes located in the palisade layer is collenchyma tissue, which is composed of elongated cells with irregularly thickened walls. The spongy layer, another component of the mesophyll, is the secondary site of photosynthesis and is spaced apart to allow carbon dioxide and oxygen to reach the palisade cells. The third part of the mesophyll, vascular tissue, transports water and nutrients throughout the leaf and contains xylem and phloem cells. The lower epidermis contains openings for gas exchange called stomata and guard cells that regulate the opening and closing of the stomata. Within the mesophyll are chloroplasts, which are mostly made up of empty space called the stroma. Chloroplasts also contain thylakoids, individual chlorophyll-containing units, and stacks of thylakoids called granum. Photosynthesis occurs on the membrane …show more content…
Enzymes for photosynthesis work best in environments between 60 and 95 degrees Fahrenheit. Any temperatures higher or lower than this will denature enzymes and cause the rate of photosynthesis to decline. Light intensity also affects photosynthesis--the brighter the light, the greater the rate of photosynthesis. This relationship continues until the plant grows too hot and a max output of photosynthesis will become evident; this is due to a lack of enzymes and other limiting reactants like water. Water availability can also alter the rate of photosynthesis. Little water will cause photosynthesis to slow down, while a large amount of water will lead to a faster photosynthesis rate. If no water is available to a plant, then no photosynthesis can