Chapter 4: Transport in plants Flashcards
What are the two main types of vascular tissues?
- xylem
- phloem
What is the necessity of transport in plants?
- needs a transport system to transport water and mineral salts
Plants that have a transport system are known as ______ _______. ___-______ _____ like alga and moss do not have any transport system.
- vascular plants
- non-vascular plants
The xylem tissue consists of ____ _____ and ______.
- xylem vessels
- tracheids
What does the xylem vessel consist of?
- dead cells at maturity which do not have cytoplasm
What is the structure of the xylem vessel?
- arranged longitudinally from end to end to form a continuous tube
Why does the xylem vessel have lignin thickening?
- give strength to prevent them from collapsing due to the tension force
- prevent it from being bent
Explain tracheids.
- consists of dead cells
- a long, narrow, and hollow tube with a tapered end
- has small openings called pits to allow water movement to adjacent cells
What does phloem tissue consist of?
- sieve tube
- companion cells
Explain the sieve tube.
- made up of living cells with no nucleus
On both ends of the sieve tube, there is a _____ _____ that has pores through which organic substances can flow from one sieve-tube to the other.
- sieve plate
Explain companion cells.
- located beside a sieve tube
- consists of a nucleus, cytoplasm, and many mitochondria
- the mitochondria provide energy to sieve tubes to transport organic substances through active transport
Explain transpirational pull.
- produced when water that is evaporated from the stoma, pulls water from the leaves
Explain capillary action.
- produced from adhesive force and cohesive force of water molecules which moves water upwards in the stem against gravity
What is root pressure?
- moves water from the soil into the xylem vessels of the root via osmosis
What are the three things that help water and mineral slats movement from the soil to the leaves?
- transpirational pull
- capillary action
- root pressure
How does water move from the soil into the xylem vessel?
- water potential in the root hair cells is lower because the mineral ions are actively pumped into the vacuole
- diffuses into root hair cells and epidermal cells via osmosis
- high water potential in the root hair cells causes the water to diffuse into cortex cells
- causes osmosis to continuously occur throughout the cortex, endodermis, and pericycle
How does water move in the xylem vessels?
- is helped by capillary action and transpirational pull
- capillary action causes water to move water upward in the xylem vessel
- during transpiration, water vapour diffuses out from the air spaces through the stoma
- spongy mesophyll cells lose water and have low water potential
- water diffuses in from the adjacent cells
- this produces a transpirational pull
What is guttation?
- a secretion of water droplets at the end of leaf veins without involving the stomata caused by a high root pressure
When does guttation occur?
- when the air humidity is high and the surrounding temperature is low
What are the similarities between transpiration and guttation?
- occur through leaf
- cause water loss from plant
What are the differences between transpiration and guttation?
Transpiration - happens on hot a day - in all plants - released as water vapor - released through the stoma - controlled by stomatal opening and closing Guttation - night and early morning - only in herbaceous plants - released as water droplets - released through the end of leaf veins - when root pressure is high
What occurs if plants do not undergo guttation?
- root pressure cannot be maintained which abrupts water absorption
- waste substances cannot be released
- causes leaf veins to burst and exposing them to pathogens
What occurs if plants do not undergo transpiration?
- optimum temperature cannot be maintained and can denature cells
- mineral ions cannot be transported
- die in the long run
What is translocation?
- transporting organic substances such as sucrose and amino acids in the phloem from the leaves to other parts of the plant
Explain the necessity of translocation in plants.
- helps in transporting photosynthetic products
- transports excess photosynthetic products to other parts of plants such as rhizomes or tubers
What are the pathways of translocation in plants?
- sucrose is actively transported into the sieve tube
- reduces water potential in the sieve tube that causes water to diffuse from the xylem into the sieve tube via osmosis
- diffusion increases hydrostatic pressure
- this causes the phloem sap to be pushed along the sieve tube to the other organs
- phloem sap ( sucrose ) is transported to parts such as stems, roots, and fruits
- high water potential in phloem causes water to diffuse into the xylem
What is phytoremediation?
- one of the treatment methods which uses plants for the purpose of degradation or elimination of pollute substances from soil and water
_____ _____ removes diesel pollutants in synthetic waste.
- floating fern ( Salvinia molesta )
____ ______ has long roots and accumulates heavy ____ such as copper and lead in water.
- water hyacinth
- metals
Sunflower acts as a __________ which can eliminate heavy metals such as ____, chromium, and lead.
- hyperaccumulator
- zinc
_____ lettuce _____ which has a fast growth rate, can accumulate heavy metals and absorb nutrients in the waste plant.
- water
- plant
What are the uses of phytoremediation?
- remove contaminants and treat polluted water
