name three reasons why multicellular plants need transport systems
metabolic demands
size
surface area to volume ratio
explain why transport systems are need to meet the metabolic demands of multicellular plants
not all parts of the plant photosynthesise but still need glucose, oxygen and hormones transported to them
and waste products need to be removed
explain why the size of a plant means a transport system is needed
to transport substances from the roots of very large plants to the top of of the plant eg. leaves
why does a surface area to volume ratio matter when talking about transport systems for plants
larger plants have a low surface area to volume ratio so they can rely just on diffusion to supply their cells with everything they need so transport system is needed
what is a series of transport vessels through stem, roots and leaves called
vascular system
what two transport vessels is the vascular system made out of
xylem and phloem
in stem the vascularbundles are around the edge to give strength and support
label stem
label ts root cell
label ts of leaf
is the xylem a living or non living tissue
non living tissue
what two main functions does the xylem have in a plant
transport of water and mineral ions
support
what are the two main cells in the vessels
xylem vessels and xylem parenchyma
what cell packs around the xylem vessels
xylem parenchyma cells
what do xylem parenchyma cells do
store food and contain tannin deposits
what are tannin deposits for
bitter tasting chemicals which protect plant tissues from being eaten by herbivores
what are xylem fibres
they are long cells with lignified secondary walls that provide extra mechanical strength but do not transport water
what does lignin do
helps reinforce the xylem vessels so they do not collapse under transpiration pull
is the phloem living or non living tissue
living tissue
what does the phloem do
transports food in the form of organic solutes around the plants from leaves
what does the phloem supply to the cells
sugars and amino acids needed for cellular respiration and synthesis of other useful molecules
in which direction is the flow of materials in the phloem
both up and down
in which direction is the flow of water in the xylem
up the plant from roots to leaves
what are the main transporting vessels of the phloem
sieve tube elements
phloem
are phloem tubes liginified
no
what are closely linked to sieve tube elements
companion cells
what are sieve tube elements made of
cells joined end to end to form a long hollow structure
what are the plasmodesmata
microscopic channels through the cellulose cell walls linking the cytoplasm between sieve tube elements and adjacent companion cells