Plant Transport
Xylem tissue Phloem
1- What is the function of xylem vessel? 3- What is the function of PHLOEM?
Transport water and minarels Transports amino acids and sucrose
Provides support to the plant from source to sink by Translocation
2- How xylem is adapted to do it's function?
- What are the adaptations of xylem?
Hollow tube ( no cell contents ) to reduce resistance to water flow
No end walls to allow water to flow easily in continuous water culomn
Ligified walls: 1- to provide support
2- acts as waterproof to prevent water loss
Pits to allow movement of water to near by cells
4- Explain how water from the soil reaches
the xylem in root?
Water moves by osmosis from soil ( higher water potential )
to root hair cells ( lower water potential ) through partially
permeable membrane
Water enters cortex layer by osmosis down water potential
gradient through partially permeable membrane
Enters the xylem through pits
, 5- How water moves up to the leaf against gravity ?
- How water from the soil reaches the leaf ?
- How transpiration helps in movement of water up the plant ?
Root
Water diffuses from the soil to root hair cells by osmosis
Down concentration gradient
Through partially permeable membrane
leaf
Water in mesophyll layers evaporates and saturates air spaces of spongy mesophyll cells
Followed by evaporation of water vapour out of the leaf through stomata by transpiration
So water potential in mesophyll cells decreases
So more water will be absorbed from xylem vessels by osmosis
Stem
Causing a water potential gradient between leaf and root
Creating negative pressure in xylem vessels
Creating transpiration pull
Which leads to tension in walls of xylem vessel
So water will move in continuous water culomn maintained by:
COHESION FORCE: Force between water molecules
ADHESION FORCE: Force between water molecules and walls of xylem vessels
Xylem tissue Phloem
1- What is the function of xylem vessel? 3- What is the function of PHLOEM?
Transport water and minarels Transports amino acids and sucrose
Provides support to the plant from source to sink by Translocation
2- How xylem is adapted to do it's function?
- What are the adaptations of xylem?
Hollow tube ( no cell contents ) to reduce resistance to water flow
No end walls to allow water to flow easily in continuous water culomn
Ligified walls: 1- to provide support
2- acts as waterproof to prevent water loss
Pits to allow movement of water to near by cells
4- Explain how water from the soil reaches
the xylem in root?
Water moves by osmosis from soil ( higher water potential )
to root hair cells ( lower water potential ) through partially
permeable membrane
Water enters cortex layer by osmosis down water potential
gradient through partially permeable membrane
Enters the xylem through pits
, 5- How water moves up to the leaf against gravity ?
- How water from the soil reaches the leaf ?
- How transpiration helps in movement of water up the plant ?
Root
Water diffuses from the soil to root hair cells by osmosis
Down concentration gradient
Through partially permeable membrane
leaf
Water in mesophyll layers evaporates and saturates air spaces of spongy mesophyll cells
Followed by evaporation of water vapour out of the leaf through stomata by transpiration
So water potential in mesophyll cells decreases
So more water will be absorbed from xylem vessels by osmosis
Stem
Causing a water potential gradient between leaf and root
Creating negative pressure in xylem vessels
Creating transpiration pull
Which leads to tension in walls of xylem vessel
So water will move in continuous water culomn maintained by:
COHESION FORCE: Force between water molecules
ADHESION FORCE: Force between water molecules and walls of xylem vessels
