Structure of a Leaf Flashcards
Where are stomata found in the leaf
Lower epidermis
What is meristem tissue
Meristem tissue is made up of plant stem cells.
Where are meristem found
They can be found on the growing tips of the shoots and roots.
Which structures help minimise water loss
- Waxy cuticle which is impermeable to water
- Guard cells which can close stomata
Is the leaf an organ, cell, or tissue?
Organ
Why is the waxy cuticle transparent?
To allow light to pass through and reach the palisade mesophyll cells which is where photosynthesis occurs
Is the spongy mesophyll layer an organ system, organ, cell, or a tissue?
Tissue
Why does the spongy mesophyll layer have so many air gaps?
To allow CO2 to diffuse from the stomata to the palisade mesophyll cells
How does the level of WATER in the plant affect the opening and closing of stomata?
When there is plenty of water in the plant, the guard cells become turgid which opens the stomata
When there is not very much water in the plant, the guard cells become flaccid which closes the stomata
Name the layers of the plants
Waxy cuticle
Upper epidermis
Palisade mesophyll layer
Spongy mesophyll layer
Lower epidermis
What layer can the xylem and phloem be found in?
Spongy mesophyll layer
Guard cells
Cells control opening and closing of stomata by changing shape
Opens during the day and closes at night
When there is plenty of water in the plant, the guard cells become turgid which opens the stomata
When there is not very much water in the plant, the guard cells become flaccid which closes the stomata
Epidermal cells
The two upper layer of cells which have very few chloroplasts. These cells produce the waxy cuticle
Palisade cells
Near the top of leaf to absorb most amount of light as it enters the leaf
Long and narrow. Contains most amount of chloroplast as it carries out most of photosynthesis
Waxy cuticle
Transparent to allow light to pass to palisade cells
Protective layer which prevents water loss by evaporation
Prevents disease-causing microorganisms from entering. E.g bacteria or fungi
Stomata
Air holes/pores in lower epidermis that allows gas exchange to occur
CO2 into - photosynthesis
O2 and water vapour out
Xylem
Transports water and mineral ions TO LEAF
Vessels create a continuous transport system (transpiration stream)
throughout plant from root, stem, and leaf.
Continuously supplied to palisade mesophyll cell bc water is vital for photosynthesis
Phloem
Sugars made during photosynthesis carried away from mesophyll cells to rest of plant
Esp to cells that cannot photosynthesise (root hair cells)
Sugars transported in solution - sucrose dissolved in water
How does the level of LIGHT in the plant affect the opening and closing of stomata?
Guard cells control the opening and closing of the stomata to prevent water loss via the stoma
Open when the light levels increase (daytime)
Close when light levels decrease (night).
