plant tissues Flashcards
name the two types of tissues
- meristematic tissue
2. permanent tissue
explain meristematic tissue
- they are actively dividing cell (mitosis)
- usually found at root and shoot tip (apical meristems )\
- responsible for increase in girt( thickness ) of root and stem
- these tissues eventually form permanent tissue
what are permanent tissue
cells are not actively dividing for growth, only for repair
- have become structurally specialised to perform specific functions
- found throughout the plant body except in meristematic regions
give example sof permeant tissue
- simple ground tissue
2. complex tissue
name the two types of complex tissue
epidermal (root stem leaves )
conducting tissue (phloem and xylem)
list the three types of simple ground tissue
parenchyma
collenchyma
sclerenchyma
what is the structure of parenchyma
Thin cell wall
Large vacuole
Round to oval inshape.
If Intercellular chloroplasts present then known as chlorenchyma.
What is the function of parenchyma
Acts as packing tissue.
Stores water,sugar(infruit)an starch.
Intercellular air-spaces-allow the gases and water to pass through the tissue
What is the structure of collenchyma
Similar to parenchyma cells
walls are unevenly thickened.
no intercellular air spaces
large vacuole
What is the function of collenchyma
Act as supporting tissue,
in young stems and leaves.
Flexible -allows plant to bend without breaking
What is the structure of sclerenchyma
Have evenly thickened cell walls impregnated with lignin.
Cells have no cell contents.
What is the function of sclerenchyma
Provide mechanical support.
waterproof n strong due to lignin
thickened cells provide stength and support stem and roots
Name the two types of complex epidermal tissues
Guard cells
root hair cell
What is the structure of guard cell
. they have no intercellular air-spaces because they are tightly packed
cells which surround a pore are kidney shaped with chloroplasts and are known as guard cells
the tissue is covered by a cuticle which is waxy and transparent, and which serves to reduce the loss of water vapour
What is the function of guard cell
Protects the inner tissues in a plant
Cuticles restrict water loss by evaporation and protect against infection by pathogens.
cuticle is transparent to allow sunlight ro pass through for photosynthesis
stomata in leaves allow for gases to enter and leave the plant.
lenticels in the stem allow gases to enter and leave the plant.
What is the structure of root hair cell
No cuticle is present
Some epidermal cells, which are modified into root hair cells, have an elongated extension
What is the function of root hair cells
modified epidermal cell sin root hair cells increase surface area to improve water absorption from thesoil.
Name the two types of conduction tissues
Phloem a
Xylem
What is the structure of phloem
Sieve tubes
Elongated, hollow cells joined end to end
Holes called pits are found on the end walls forming sieve plates
? No nucleus present
Companion Cells
? Found next to a sieve tube
? Has a large nucleus, in addition to other organelles
What is the function of phloem
Phloem transports manufactured food in solution from the leaves to all parts of the plant
A companion cell controls the functioning of a sieve tube element.
What is the structure of xylem
Xylem vessels
? consists of dead cells
elongated, hollow and joined end to end to form long tubes
? walls lignified with incomplete thickenings
cross walls are also perforated or absent (disintegrated) to allow for rapid movement of water
Tracheids
consists of dead cells
? long and tapered at both ends
walls are lignified with pits.
What is the function of xylem
xylem transports absorbed water and mineral salts from the roots to the stem and leaves.
xylem tissue gives plants strength and flexibility.
