Transport in plants Flashcards
Define transpiration
process by which water evaporates from the leaves driving movement of water through the plants
Why is transipration good for the plant? [3]
1) Transport water for photosynthesis
2) Cools down leaves
3) Transport mineral ions for growth
How does the transpiration stream happen in plants [5]
1) Transpiration is caused by the evaporation/diffusion of water from the surface of leaves
2) This decreases the concentration of water in leaves
3) Water is drawn up from the roots by the xylem
4) To replace water loss
5) This causes a constant transpiration stream of water
Adaptation of the xylem and how it helps the cell
1) Cells are joint end to end to form a long continous tube for transport
2) no cell contents so water pass through freely
3) Outer walls contain lignin and helps support the plant
What happens to the cells when leafs begin to wilt [5]
1) Water moves by osmosis
2) Water is lost from cells
3) Pressure of wate ron cell wall decreases
4) Plants rely on water to prevent wilting
5) Wilted cells are not replaced fast enough
Advantages for plant to wilt [2]
1) CLose the stomata
2) To prevent more water loss
Compare transpiration with translocation
1) They both are in the vascular bundle
2) Transpiration occurs in the xylem Translocation occurs in the phloem
3) Transpiration only travels upward where translocation travels in both directions
4) Transpiration invovle some dead tissues while translocation needs live tissues to function
term ‘source’ when used in the context of plant biology means [1]
1) Parts of the plant that release sucrose or amino acids
What allows water to move up the xylem vessel?
1) The cohesion of water molecules and adhesive to cell walls
2) Water molecules are held together by forces of attractions between water molecules
How to track the movement of water through xylem vessels? [3]
1) Put a cut plant revealing its cross section in a beaker of dye
2) The dye water will travel up the vessel
3) After 3 days the xylem vessel will show up in darker colours as the dye moving up the vessel has stained it
There are many air spaces in the leaf. Explain how this aids water loss with transpiration [2]
1) Increase surface area for water to cling on by cohesion
2) Evaporation is faster because more water vapour can evaporate in the same time
When stomata open, they allow water to escape from the leave. In terms of changes in term of water potential and evaporation, describe how this encourages more water to move towards the leaves.
1) When the stomata opens, carbon dioxide enter the leaf which lowers water potential inside the leaf
2) Water move towards the leaf as water move from areas of high water potential to low water potential
Define sink
Parts of plants that use or store sucrose or amino acids
