The lower epidermis is located on the underside of leaves. Stomata are usually present on the lower epidermis. In order to minimize transpiration that occurs with gas exchange, most dicot plants have their stomata on the lower epidermis. On the other hand, monocot plants such as corn can have their stomata on both the top and bottom sides of leaves. This is because corn leaves grow upright rather than parallel to the ground and therefore both upper and lower surfaces of leaves experience transpiration.
Chloroplasts and Photosynthesis Inside chloroplasts, there are membrane bound structures called thylakoids that are surrounded by the stroma see Figure 2. Stomata and Gas Exchange Stomata or pores in the leaf surface are surrounded by specialized leaf cells called guard cells see Figure 3. How is the opening and closing of stomata regulated? Glossary Air spaces: Spaces between spongy mesophyll cells where gas exchange takes place. Carbon dioxide: A gas used by plants for photosynthesis; a gas produced as waste by animals during cellular respiration.
Chlorophyll: A class of pigments produced in plants that give plants their green colour. Chloroplast: An organelle found in plants and some algae where photosynthesis takes place. Cuticle: A waxy layer usually present on the outside of the epidermis in plants. Dicot: A group of flowering plants. The seeds in this group of plants contain two seed leaves.
Epidermis: A single layer of cells that covers all parts of a plant. Grana singular granum : A stack of thylakoid discs that resembles a stack of coins or pancakes.
Guard cells: Specialized cells surrounding stomata that also control stomatal opening and closing. Lamellae: Connect grana stacks together. Monocot: A group of flowering plants. The seeds in this group of plants contain one seed leaf.
Osmosis: The movement of molecules through a semi-permeable membrane from a region of higher concentration to lower in order to equalize the concentration on both sides of the membrane. Oxygen: A gas used by animals during respiration; a gas produced by plants during photosynthesis. Palisade mesophyll layer: Tightly packed layer of elongated cells located directly below the upper epidermis. Phloem: Specialized cells within vascular bundles that transport nutrients throughout the plant.
Photosynthesis: The process used by plants to change light energy into biochemical energy sugar. Potassium: A major ion present inside cells. Protons: Positively-charged particles that are found in the nucleus of every atom. Respiration: The process used by plants and animals to get energy from sugar molecules.
Spongy mesophyll layer: A loosely packed layer of irregularly-shaped cells. Stomata singular stoma : Small pores holes located on leaves. Stroma: The fluid surrounding the grana within chloroplasts. Thylakoids: A membrane bound structure within the chloroplast. Transpiration: The process of water movement through plants and eventual evaporation from small pores, or stomata, in leaves. Vacuole: An organelle that stores food, nutrients or waste for a cell.
Vascular bundles: Strands of vascular tissues connecting all of plant parts in order to transport nutrients and water through phloem and xylem. Water vapour: Water molecules in the form of gas. Xylem: Specialized cells within vascular bundles that transport water throughout the plant. When the plant is photosynthesising during the day, these features allow carbon dioxide to diffuse into the spongy mesophyll cells, and oxygen to diffuse out of them.
To enter the leaf, gases diffuse through small pores called stomata. As the stomata open, water is lost by the process of transpiration. Closing the stomata helps to control water loss. To enter the leaf, gases diffuse through small pores called stomata. As the stomata open, water is lost by the process of transpiration. Closing the stomata helps to control water loss. Plant issues - epidermis, palisade mesophyll and spongy mesophyll The structure of a leaf Plant leaves are adapted for photosynthesis , and the exchange of gases required for the process.
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