Xylem and Phloem

• The stem, root and leaves form an organ system that transports substances into, around and out of a plant.
• Transpiration is a process in plants where water is evaporated through the stomata, aiding in the transport of substances through the plant.
• Factors affecting transpiration include environmental conditions such as temperature and humidity.
• Potometers are used to measure water uptake in plants.
• Factors affecting transpiration include environmental conditions such as temperature and humidity.
• Environmental factors can influence the distribution of stomata and guard cells.
• Xylem is the tissue in plants that transports water and minerals from the roots up the plant stem and into the leaves.
• In a mature flowering plant or tree, most of the cells that make up the xylem are specialised cells called vessels.
• Vessels lose their end walls so the xylem forms a continuous, hollow tube.
• Lignin, a carbohydrate material, lines the xylem vessels providing strength and support.
• The cells in xylem are no longer alive.
• Lignin gives strength and support to the plant.
• The cells that make up the phloem are specialised for transport and have no nuclei.
• One or more companion cells attached to each sieve tube provide this energy.
• Each sieve tube has a perforated end so its cytoplasm connects one cell to the next.
• Transport of substances in the phloem is called translocation.
• A sieve tube is completely dependent on its companion cell(s).
• In the xylem, transport is a physical process that requires energy and transports water and minerals upwards.
• In the phloem, transport is a physical process that requires energy and transports products of photosynthesis; includes sugars and amino acids dissolved in water upwards and downwards.
• Companion cells are the cells that lie alongside a sieve tube in the phloem, and provide the sieve tube with energy to transport sugars and amino acids in solution.
• We call lignified cells wood.
• Transport of substances in the phloem requires energy.
• Transport in the phloem is both up and down the stem.
• Chromosomes are structures found in the nucleus of most cells.
• The plural of nucleus is nuclei.
• The nucleus controls what happens inside the cell.
• Transport in the xylem is a physical process that does not require energy.
• Phloem is the tissue in plants that transports the products of photosynthesis, including sugars and amino acids.
• Phloem moves food substances that the plant has produced by photosynthesis to where they are needed for processes such as growing parts of the plant for immediate use and storage organs such as bulbs and tubers.
• A tuber is a swollen, fleshy underground stem of a plant, such as the potato, bearing buds from which new plant shoots arise.
• Developing seeds are a process in plants where seeds are formed and mature.