Transport In Plants Flashcards
(69 cards)
What do xylem vessels transport?
Water from roots to leaves for use in photosynthesis
What are the characteristics of xylem vessels?
Long, narrow, hollow tubes that are non-living and formed from columns of elongated cells
What happens to the cells that form xylem vessels?
The contents die, cross walls breakdown, and cellulose walls thicken with lignin
How does the structure of xylem vessels facilitate water movement?
Being long, narrow, and hollow with no cross walls allows continuous water flow
What is the role of lignin in xylem vessels?
Lignin provides toughness and strength, helping to support the plant
What is the primary composition of wood?
Almost entirely composed of lignified xylem vessels
List the three mechanisms by which water moves through a flowering plant.
- Root pressure
- Transpiration
- Capillarity
What is root pressure?
A push from the roots that moves water into the xylem
How does water enter root hairs?
By osmosis
What creates root pressure?
Water entering root hairs and moving through cortex cells
Define transpiration.
The loss of water vapour from the surface of leaves
What initiates the pull in transpiration?
Water evaporating from spongy mesophyll cells
How does capillarity assist in water movement?
Xylem vessels act like capillary tubes due to their narrowness
Fill in the blank: The cohesion between water molecules and the _______ of the molecules to the xylem walls helps water movement.
adhesion
True or False: Xylem vessels are living structures.
False
What are the three processes involved in the movement of water through a plant?
- Root pressure
- Transpiration
- Capillarity
What role do palisade cells play in relation to water?
They use some of the water for photosynthesis
What is the waxy cuticle?
A protective layer on the surface of leaves that reduces water loss.
What is the function of the upper epidermis?
It provides protection and helps reduce water loss from the leaf.
What is palisade mesophyll?
A layer of cells in the leaf where most photosynthesis occurs.
What is spongy mesophyll?
A layer of loosely packed cells in the leaf that facilitates gas exchange.
What is the role of the lower epidermis?
It contains stomata for gas exchange and helps control water loss.
What is a stoma?
A small opening on the leaf surface that allows for gas exchange.
What is the transpiration stream?
The flow of water through the xylem vessels from roots to leaves.