Plant organisation Flashcards
Waxy cuticle
Reduces evaporation from the surface of the leaf
Helps prevent the leaf from drying out
Upper and lower epidermis
Protects surface of the leaf
Upper is transparent that allows light to pass through for photosynthesis
Lower epidermis has stomata - controls water vapour levels
Palisade cells
Packed full of chloroplasts, where photosynthesis occurs
As chlorophyll absorbs sunlight
Spongy mesophyll
Air spaces to allow carbon dioxide to diffuse from the stomata through the spongy mesophyll so it can reach palisade cells for photosynthesis
Allows oxygen to diffuse through the spongy mesophyll to the stomata
Stomata
Allows carbon dioxide to enter and oxygen to leave the leaf
Also controls amount of water vapour to pass out of the leaf by osmosis
As there’s a high concentration of water inside than outside leaf
Guard cells
Opens and closes stomata to control water vapour loss
Xylem
Made up of dead cells with lignin
Transports water and minerals from the roots to stem and leaf
Dissolved mineral ions (Mg+ ions) to make chlorophyll
Water for photosynthesis
Phloem
Transports products of photosynthesis to where it is needed ie sucrose and amino acids. This is translocation
Can be used for respiration
Store east starch
Adaptation: Large surface area
Absorbs more light
Adaptation: Network of veins
To support the leaf and transport water, mineral ions and sucrose
Adaptation: Thin
Shorter diffusion distance
Epidermal tissue
Made of epidermal cells at the top and bottom
Cover the leaf to protect the surface
Translocation
Movement of sugars through the phloem tissue
Meristem tissue
At growing tips such as shoots/roots
Contain stem cells that can differentiate into any different type of cell
Transpiration
When water vapour evaporated from surface of the leaves because the plant takes in too much water at a given time for photosynthesis to remove excess
