The Photosynthesis-yuanmu

Arts-and-Entertainment When the leaf chlorenchyma is differentiated into palisade parenchyma and parenchyma lagunoso, the cloud is said heterogeneous. Depending on the location of the two types of chlorenchyma are three types of mesophyll structure. The dorsiventral mesophyll is the type of structure in which the palisade chlorenchyma is toward the adaxial side of the leaf and chlorenchyma lagunoso to the abaxial surface, as is the case of grapevine ( Vitis ) and privet ( Ligustrum ). This organization is usually found in the leaves that are oriented horizontally. The number of layers of palisade chlorenchyma is variable: there is only one in the case of snuff ( Nicotiana tabacum ) and potato ( Ipomoea batatas ) , two in the pink bay ( Nerium oleander ) and alfalfa ( Medicago sativa ) and three for pear ( Pyrus ) . The number of layers of palisade chlorenchyma may even vary from one sheet to another of the same individual. Thus, in the case of maple ( Acer platanoides ), a broad crown tree, the leaves are more peripheral chlorenchyma layers than those found inside the cup. Also, the leaves are more exposed to the sun are thicker than those in the shade, have a greater development of palisade chlorenchyma and a greater number of chloroplasts. The isobilateral cloud structure is one in which the palisade chlorenchyma is on both sides of the leaf blade and parenchyma lagunoso is in between them. This organization is characteristic of plants with leaves erect or pendulous, such as carnation ( Dianthus ). The central cloud is a type of structure found in species with leaves very narrow, almost cylindrical. In this type of organization of the mesophyll the adaxial palisade parenchyma form an almost continuous layer with the abaxial, eg in Salsola . This structure is common in xerophytic plants and succulents, which contains small cell mesophyll, the palisade chlorenchyma is more developed than the spongy and is often reinforced by sclerenchyma . Transpiration is a process similar to evaporation . Is a part of the water cycle and is the loss of water vapor from parts of the plant , especially the leaves, but can also be produced from the stalks . Most of perspiration, however, occurs through the stomates. The opening and closing of these structures has an associated energy cost, but permits the diffusion of carbon dioxide necessary for photosynthesis from the air into the interior of the sheet, the oxygen outlet from inside the leaf outward and loss water vapor. Transpiration also cools plants and enables mass flow of mineral nutrients and water from the roots to the leaves. This mass flow of water from the roots to the leaves is caused by decreasing the hydrostatic pressure in the upper parts of the plants due to diffusion of water from the stomata to the environment . Water is absorbed from the soil into the roots through the process of osmosis and any dissolved mineral water will be carried to the leaves through the xylem . 36 Transpiration rate is directly related to the evaporation of water molecules from the surface of the plant. Stomatal transpiration represents most of the loss of water by a plant, although some direct evaporation also takes place through the cuticle of the leaves and stems of young. The amount of water that emerges depends somewhat on the amount of water that the plant roots have absorbed. Also depends on environmental conditions such as light intensity, humidity, wind speed and temperature. Transpiration occurs when the sun heats the water inside the leaf. This heating changes much of the water into steam and this gas can escape to the environment through the stomatal pore. Perspiration helps to cool the interior of the sheet because the steam escapes into the atmosphere has absorbed heat. The amount of water lost through plant transpiration stomatal depends on its size, the light intendidad the degree of stomatal opening and the evaporative demand of the atmosphere surrounding the leaf. 37 A fully grown tree may lose several hundreds of liters of water through its leaves on a hot day and dry. About 90% of water entering the roots of the plant is used for this process. In this regard, it is called water-use efficiency to the relationship between the mass of water transpired with respect to the mass of dry matter produced by a plant. This ratio is between 200 and 1000 for most crops, ie crop plants transpire between 200 and 1000 kg of water per kg of dry matter produced. The photosynthesis is the process by which the inorganic matter is converted into organic compounds by the energy provided by light. In this process the light energy is converted into chemical energy stable, with the adenosine triphosphate (ATP), the first molecule in which the chemical energy is stored. Subsequently, the ATP is used inside the cell to synthesize more stable organic molecules such as carbohydrates. Each year, photosynthesizing organisms fixed in form of organic matter around 100,000 tonnes of carbon. About the Author: 相关的主题文章:

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