Plant Physiology - Skeleton Notes.pptx

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Chapter 9 Plant physiology Vascular tissue Vascular tissue is transport tissue that is composed of phloem and xylem. Xylem Xylem tissue transports water and minerals from the roots up to the leaves. Phloem Phloem transports...

Chapter 9 Plant physiology Vascular tissue Vascular tissue is transport tissue that is composed of phloem and xylem. Xylem Xylem tissue transports water and minerals from the roots up to the leaves. Phloem Phloem transports sugars produced by photosynthesis from the leaves to other parts of the plant for storage. Photosynthesis and the structure of the leaf Plants are autotrophic, which means they can produce their own food. Photosynthesis and the structure of the leaf The chlorophyll molecule absorbs light energy from the sun and uses this energy to combine hydrogen from water and carbon dioxide from the atmosphere to produce glucose and oxygen. Photosynthesis and the structure of the leaf Excess oxygen is excreted by the stomata. Photosynthesis and the structure of Stomata allow for The palisade layer the of leaf gaseous exchange to cells are packed with occur, with carbon chloroplasts and it is dioxide diffusing into these cells that carry the leaf for out the majority of photosynthesis and photosynthesis. oxygen and water vapour diffusing out. The opening and closing of the stomata are controlled by the guard cells. Respiration Both plant and animal cells obtain their energy in the form of ATP by aerobic respiration. Respiration Glycolysis is the first stage of respiration. It occurs in the cytosol of the cell and produces two molecules of pyruvic acid and a small amount of energy. Oxygen is not required for this stage. Respiration Inside the mitochondria, in the presence of oxygen, the pyruvic acid is completely broken down into carbon dioxide and water. This produces a large of amount of ATP. Water transport The movement of water from the roots to the leaves of plants is caused by a combination of: Root pressure Cohesion–tension Transpiration. Water transport The movement of water in the xylem vessels from the roots to the leaves is called the transpiration stream. Root pressure Root pressure is caused by the continuous movement of water by osmosis from the soil into the root hairs. Transpiration Water is constantly lost through the stomata in the leaves by evaporation, which draws the water out of the xylem vessels to replace water lost. Nutrient absorption Root hairs greatly increase the surface area for the uptake of water and the absorption of nutrients from the soil. The nutrients are absorbed into the root hairs from the soil solution by active transport. Nutrient absorption The endodermis cells are embedded in the Casparian strip. The Casparian strip is an important barrier that regulates the uptake of water and nutrients and also protects the plant. Nutrient absorption Some symbiotic relationships between plants and microorganisms help to improve the uptake of nutrients from the soil. Credit slide Shutterstock

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