3.3.1 transport in plants Flashcards
dicotyledonous plants
plants with 2 seed leaves & branching pattern of veins from leaf
meristem
layer of dividing cells (pericycle)
phloem
transports dissolved assimilates
vascular tissue
consists of cells specialised for transporting fluids by mass flow
xylem
transports water & minerals
why do multicellular plants need a transport system?
- smaller SA:Vol
- deliver nutrients & remove waste products
- different nutrient requirements - eg. autotrophic
- metabolism in plants is generally slower (than animals)
- nutrients supplied at lower rate
- transport system doesn’t need to be as effective
- no need for pump
- some nutrients supplied by diffusion eg. photosynthetic gases
what does the transport system in plants consist of
specialised vascular tissue
name the 2 specialised vascular tissue & what they transport
- xylem tissue = water & soluble mineral ions travel upwards
- phloem tissue = assimilates (eg. sugars) travel up OR down
describe the distribution of vascular tissue in dicotyledonous plants
- distributed throughout the plant
- xylem & phloem found together in vascular bundles
- bundles may also contain other tissues (eg. collenchyma, sclerenchyma) which give bundle more strength/support plant
where is the vascular bundle found
centre of young root
describe the structure of the vascular bundle in the root (diagram)
- central core of xylem (often in X shape)
- phloem found between arms of X-shaped xylem tissue
–> provides strength to withstand pulling forces to which roots are exposed
what components are also present around the vascular bundle in the root
- around bundle, special sheath of cells called endodermis
- inside endodermis = layer of meristem cells called pericycle
in a plan diagram of a root, where is the medulla located
between central vascular bundle & endodermis
endodermis key role
getting water into xylem vessels
draw & label plan diagram of a root
pg. 208 of textbook & in class booklet
where are the vascular bundles found within the stem
found near outer edge
what are the vascular bundles like in non-woody plants
separate & discrete
what are the vascular bundles like in woody plants & what does this provide the plant with
bundles are separate in young stems, but become continuous ring in older stems
–> provides strength & flexibility to withstand bending forces to which stems/branches are exposed
describe stem plan diagram referring to only phloem and xylem
- xylem found towards inside of vascular bundle
- phloem on outside of vascular bundle
- in between phloem/xylem = cambium
what’s the cambium
layer of meristem cells that divide to produce new xylem/phloem
phloem consists of
sieve tube element & companion cell
draw a plan diagram of a stem
pg 209 in textbook & in class booklet
describe leaf plan diagram/structure
- vascular bundles form midrib & veins of leaf
- dicotyledonous leaf has branching network of veins that get smaller as they spread away from the midrib
- each vein = xylem located on top of phloem
name components of leaf plan
- xylem & phloem (midrib)
- upper epidermis
- palisade mesophyll
- vein
- spongy mesophyll
- lower epidermis
