Transport in Plants Flashcards
why is water important for plants (4)
turgor pressure
cools the plant
photosynthesis
transport minerals and assimilartities
name the specific palnt to know to descivre vascular systems in plants
dicotyledonous plant
what are main features of dicotyledonous plant
embroyonic leaf in seed bearing plants
why are plant transport systems important
To take substances from & retuen waste to enviornment
which vascular vessel is used in transpiration
xylem
which vascular vessel is used in trasnlocation
phloem
name cell types forund in plant stem (3)
epidermis, vascular bundle, parenchyma
name types of cells found in roots(4)
endodermic, vascular bundle, medulla, epidermis
name cells found in leaves (2)
palisade mesophyll cells, vascular bundle
what is the bulge in leaf crosssection
midrib of leaf
endodermis defintiion (2)
a layer of cells surrounding the vascular bundle in the root of the plant(1), helping in water movement in the Casparian strip (2)
parenchyma definition
a packing tissue in plants which fills spaces between other tissues
collenchyma definition (3)
cells with thick cellulose walls (1) strengthens vascular bundles & outer parts of stems (2) whilst allowing some flexibility(3)
sclerenchyma definition
plant cells that have lignified walls (1) used to strengthen stems & midribs(2) solid & non living cells (3)
How are xylem vessels formed (2)
lignin fills cell wall - waterproof & kills the cell (1)
end walls & contents decay (2)
give 3 functions of lignin
kills xylem cells(1)
strengthens vessel walls to prevent collapse of stem(2)
waterproof xylem (3)
what three patterns can lignin thicken around xylem
reticulate, rings, annular
Features of xylem vessel (4)
continuosus narrow column (1)
bordered pits in cell wall (2)
lignified cells (3)
no cytoplasm or nucleas; dead cells (4)
why are bordered pits present in xylem vessels
gaps in cell wall where lignification isn’t complete (1) lets water pass sideways to adjacent vessels/tissues (2) as lignin is water proof(3)
why is lignin laid down in reticulate, rings, annular
allows xylem to stretch as plant grows = bend due to fleivibility
what is carried in phloem
assimilates
what are in assimilates
sucrose & amino acids
phloem defintiion
vascular vessel that transports assimilaties up and down the plant in translocation
which vascular vessel goes up and down the plant
phloem
name 2 features of phloem
sieve tube elements & companion cells
what are the cells which provide metabolic activity to phhloem
companion cells
what are companion cells
small cells with nucleus & many mitochondria (1) carry out metabolic activities for phloem (2) and loads assimilates into phloem (3)
what are sieve tube elements
cells which make up phloem vessel
sieve tube features (3)
end to end alignment (1) no nucleus & little cytoplasm(2) contains sieve plates (3)
what are sieve plates
perforates sieve tube elements end wall (1) allows sap movement & keeps lumen open (2)
why are sieve plates in phloem, why not just hollow
Sieve plates are sites of callose deposition (1) after plant is injured or infected (2)
which vascular vessel is lignified
xylem
what is plasmodesmata
cytoplasmic connections between adjacent plant cells passing through pits in cell wall
give an example of when sucrose can be trasnported upwards by plant (2)
In spring, the roots act as a source; this pushes the sucrose solution away from the root.(3)
give an example of when sucrose can be trasnported down by plant (2)
In summer, the leaves are making sugars and become the source for that sieve tube.
why woudl roots of xerophytes be adapted to be long
to reach water deep in soil;
why woudl roots of xerophytes be adapted to be widespread
to absorb water from a
large area when it does rain
why can’t many plants survive arid conditions (3)
They lose water through transpiration. (1) If water is not available from soil, the cells will become flaccid, (2) and the
plant will wilt and die. (3)
why is rolled leaf/pits/hairs an adaptation for xerophytes
- lower water potential gradient
- water must diffuse a greater distance from the leaf
why do some plants die if completely submerged in water (3)
Roots gain oxygen from air spaces in soil (1) water logged soil has no air (2) Roots cannot gain oxygen and respiration
fails to produce enough energy. (3)
explain why leaves in water can’t transpire (2)
Transpiration is the loss of water vapour from the leaves. (1)
If the leaves are submerged, the water vapour in the
leaves cannot move out by diffusion (2)
xerophytes adaptations in leaf advantages (3)
curled leaf/ hairs
spines instead of leaves
thick waxy cuticle
stoma is in sunken pits
how does waxy cuticle reduce water loss from leaves (2)
it acts as a barrier to evaporation a(1)nd also the shiny surface reflects heat and so lowers temperature.(2)
how do assimilarties diffuse from companion cells to sieve tubes
by plasmodesmata
transpiration definition
evaporation of water vapour from aerials parts of plant via stomata
what are the three types of pathways of water transfer
symplast, apoplast, vacuolar
name a feature about trasnpiration stream
its continous
