C4 Transport Flashcards
types of vascular tissues
xylem and phloem
function of xylem tissues
1) to transport water and mineral salts absorbed by the roots to the leaf and stems
2) to provide mechanical support to the plant
function of phloem tissues
1) to transport organic compounds which are synthesized by the leaves through photosynthesis to the stem and roots
examples of vascular plants
mango tree
examples of non-vascular plants
alga, moss
composition of xylem
1) xylem vessels and tracheid
structural adaptions of xylem tissues
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composition of phloem
companion cell and sieve tube
structural adaptions of phloem tissues
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three movements that helps the transportationn of water from soil to leaves
1) traspirational pull
2) capillary action
3) root pressure
explain transpirational pull
is produced when the water that is evaporated from the stoma, pulls water from the leaves
explain capillary action
is produced from adhesion force and cohesive force of water molecules which moves water upwards in stem against gravity
explain root pressure
transport water from soil into the xylem vessels of root via osmosis
how does water moves from root to xylem vessels
1) The water potential of the root hair cell is lower compared to the water potential in the soil
2) This is because mineral ions are actively pumped by root hair cell into the vacuole, causing the cell sap of root hair cell to have low water potential compared to the soil
3) Water diffuses from the soil into the root hair cell and epidermal cell via osmosis
4) The high water potential in the root hair cell causes the water to diffuse from root hair cell into the cortex via osmosis
5) This condition causes osmosis to continuously occur throughout the cortex, endodermis and pericycle layeres.
6) This causes root pressure to push water into the xylem vessels of the leaves and then into the xylems vessels of the stem.
How does water moves in the xylem vessels
1) For tall plants, root pressure cannot transport water to the leaves, especially the shoots
2) Therefore the movement of water is also helped by transpirational pull and capillary action
3) the adhesion and cohesion force produces a pulling force which can continuously moves the water in the xylem vessels
4) When transpiration process occurs, the water diffuses out as water vapour from the spaces between the cell to the surrounding through opened stoma
5) The spongy mesophyll cells lose water and have low water potential compared to adjacent cells
6) water molecules diffuses from the neighbouring cells via spongy mesophyll cells by osmosis
7) This movement produces a force, transpirational pull that pulls water molecules in the xylem vessel of the leaves to the outside of theleaves.