Transport systems in plants Flashcards
What do dicotyledous plants make?
seeds with two cotyledons
What do cotyledons do?
store for developing plant embryos.
what are the two vascular bundles?
xylem and phloem
How do the vascular bundles help?
provide strength /support
First outer layer of root cell?
exodermis
Second layer of root cell?
epidermis
Inner layer of root hair cell?
endodermis
what does the midrib of the leaf do?
1)Main vein carrying vascular tissue through organ 2)Supports structure of leaf
What does the xylem do
Transports water & mineral ions up the plant (roots to shoots/leaves)
Characteristics of xylem
Supports plant (keeps it upright) uses chemical lignin which is deposited on cell walls
Why does the xylem need to be dead
Xylem needs to be dead in order to deposit the lignin
How does lignin help
helps withstand pressure of transpiration pull
what is the transpiration pull
transport of water up the plant
does the xylem have organelles
no, its a hollow tube
what do non lignified pits do
allow water and minerals out the xylem
2 characteristics of xylem parenchyma cells
1) food store
2) contains tannin- is a bitter chemical defence mechanism against herbivores
characteristics of lignified cell walls
1) rings or spirals
2) provides strength
what does the phloem do
transports sugars (sucrose) up and down the plant
what does assimilates mean
food products (sucrose)
why are sugars converted into sucrose
sucrose is less reactive, isn’t used up in respiration
why does the phloem need to be alive
contains organelles which are needed for active transport (translocation) . It requires energy for this (mitochondria).
what is the plasmodesmata
gaps that link the cytoplasm with the adjacent cells
what does the companion cells do
1) involved in translocation
2) keeps phloem alive
