which helps the leaves to capture the energy of the sunlight for the process of photosynthesis. (i) guard cells (ii)stomata (iii)Nucleus (iv)Chlorophyll
Answers
Answer:
Explanation:
Guard cells are specialized plant cells in the epidermis of leaves, stems, and other organs that are used to control gas exchange. They are produced in pairs with a gap between them that forms a stomatal pore. The stomatal pores are largest when water is freely available and the guard cells turgid, and closed when water availability is critically low and the guard cells become flaccid. Photosynthesis depends on the diffusion of carbon dioxide (CO2) from the air through the stomata into the mesophyll tissues. Oxygen (O2), produced as a byproduct of photosynthesis, exits the plant via the stomata. When the stomata are open, water is lost by evaporation and must be replaced via the transpiration stream, with water taken up by the roots. Plants must balance the amount of CO2 absorbed from the air with the water loss through the stomatal pores, and this is achieved by both active and passive control of guard cell turgor pressure and stomatal pore size.
In botany, a stoma (plural "stomata"), also called a stomate (plural "stomates") is a pore, found in the epidermis of leaves, stems, and other organs, that facilitates gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the stomatal opening.
The term is usually used collectively to refer to the entire stomatal complex, consisting of the paired guard cells and the pore itself, which is referred to as the stomatal aperture.[1] Air enters the plant through these openings by gaseous diffusion and contains carbon dioxide which is used in photosynthesis and oxygen which is used in respiration. Oxygen produced as a by-product of photosynthesis diffuses out to the atmosphere through these same openings. Also, water vapor diffuses through the stomata into the atmosphere in a process called transpiration.
Stomata are present in the sporophyte generation of all land plant groups except liverworts. In vascular plants, the number, size, and distribution of stomata vary widely. Dicotyledons usually have more stomata on the lower surface of the leaves than the upper surface. Monocotyledons such as onion, oat and maize may have about the same number of stomata on both leaf surfaces.[2]:5 In plants with floating leaves, stomata may be found only on the upper epidermis and submerged leaves may lack stomata entirely. Most tree species have stomata only on the lower leaf surface.[3] Leaves with stomata on both the upper and lower leaf are called amphistomatous leaves; leaves with stomata only on the lower surface are hypostomatous, and leaves with stomata only on the upper surface are epistomatous or hyperstomatous.[3] Size varies across species, with end-to-end lengths ranging from 10 to 80 µm and width ranging from a few to 50 µm.