Transport in Plants Flashcards
dicotyledonous plants
plants with 2 seed leaves and a branching pattern of veins in the leaf
meristem
a layer of dividing cells (the pericyle)
phloem
transports dissolved assimilates
vascular tissue
consists of cells specialised for transporting fluids by mass flow
xylem
transports water and minerals
companion cells
cells that help to load sucrose into the sieve tubes
sieve tube elements
make up tubes in phloem that carry sap up and down the plant (separated by sieve plates)
plasmodesmata
gaps in the cell wall containing cytoplasm that connects 2 cells
potometer
device that can measure rate of water uptake as a leafy stem transpires
transpiration
the loss of water vapour from the aerial parts of a plant, mostly through stomata in the leaves
adhesion
the attraction between water molecules and walls of the xylem vessel
cohesion
attraction between water molecules cause by hydrogen bonds
hydrophyte
a plant adapted to living in water or where the ground is very wet
xerophyte
a plant adapted to living in dry conditions
assimilates
substances that have become part of the plant
sink
a part of the plant where those materials are removed from the transport system
source
a part of the plant that loads material into the transport system
translocation
the transport of assimilates throughout a plant
xylem tissue consists of
vessels to carry water and dissolved mineral ions, fibres to help support plant, living parenchyma cells as packing tissue to separate and support the vessels
function of phloem tissue
transport assimilates (mainly sucrose and amino acids) around the plant
cambium
layer between xylem and phloem, has meristem cells that divide to form new xylem and phloem
pericycle
parenchyma cells which remain meristematic and divide to form lateral roots
cortex
large space surrounding vascular bundle composed of parenchyma
3 pathways in root hair cells taken by water
symplast, vascular, apoplast
where does water evaporated from in plants
via stomata of leaves, cuticle of leaves, stems (via lenticles on woody stems and somata on herbaceous stems) and flowers
transpiration
driving force behind the uptake of water from the soil and its delivery to the leaves due to transpiration stream
stomata
a pore essential for exchanging gases for photosynthesis/respiration but allow water loss
guard cells
2 kidney shaped cells which open and close the stomata via change in their turgidity (cellulose walls are thickened –> less flexible)
when stomata are closed…
guard cells less turgid, less curved, water being lost
when stomata are open…
guard cells more turgid, more curved, water being gained
hydathodes
specialised structures at tips/margins of hydrophyte leaves, they can release water droplets which may evaporate from the leaf surface
what happens if phloem vessel if cut
pores in the sieve plates become blocked very quickly by proteins than callose which stops the sap from flowing
2 types of terrestrial plants
xerophytes and hydrophytes
