transport in plants (ch9) Flashcards
vascular (conductive) tissues
take food/water from one part of a plant to another
advantages of vascular tissues?
they allow rapid growth and food storage.
dermal tissue
composes outermost layer of plant, prevents damage and water loss.
what cells is the dermal tissue made out of?
parenchyma cells
ground tissue
most abundant tissue, carries out important functions of the plant (eg: photosynthesis)
primary growth (herbaceous plants)
develop tissues, and then stop growth. will typically die after one growing season.
secondary growth (dicatyledon plants)
will continue to develop additional tissues, which enables plant to grow taller and wider.
3 organs of plant:
root, stem, leaf
what is the aim of plant organs?
they work together to provide the plant with sufficient water.
3 functions of root:
-absorbs nutrients & water.
-anchors plant to ground.
-stores leftover food.
3 functions of stem:
-xylem, transports water & minerals from roots to leaves.
-phloem, transports sugars from leaves to rest of plant.
-plant support.
2 functions of leaf:
-undergoes gaseous exchange with atmosphere.
-absorbs sunlight to manufacture food, through photosynthesis process.
epidermis
waxy outer layer of plant (found on stem & leaf) that prevents water loss.
trichomes
hair like structures on leaves that prevent insects from damaging plant by secreting toxic/sticky fluids.
function of root hair cells?
maximise the surface area of roots for absorption of water.
function of xylem?
transports water & minerals from roots to leaves.
evapotranspiration
the evaporation of water from leavesh
how does evapotranspiration help water transport in plant?
it creates a negative pressure in the xylem, so that water travels up, conflicting gravitational forces.
collenchyma cells
-elongated, thich walled cells that support plant.
-found in herbaceous plants.
lignin
strong polysaccharide which increases rigidity and decreases flexibility of plant cell walls.
sclerenchyma
-provide structural support to dicotylendoneous plants.
-made up of bundles of long, dead cells.
-hollow lumen.
-cells walls are thickened with lignin (support).
stomata
pores in surface of leaf/stem (epidermis tissue) that can be opened/closed by guard cells.
function of phloem?
transports sugars from leaves to rest of plant.
feature of phloem?
composed of stacked tube cells with perforated plates (sieve pores) at each end.
photosynthesis word equation?
carbon dioxide + water -> oxygen + glucose
photosynthesis symbol equation?
6CO2 + 6H2O → C6H12O6 + 6O2
perennial plants
plants with a lengthy life cycle that continuously reproduce
vascular plants
plants that have specialised tranposrt systems
transpiration system
-the movement of water molecules and dissolved mineral ions.
-involves xylem vessels.
-passive process.
translocation system
-the movement of sugars (sucrose) and amino acids.
-involves phloem vessels (sieve and companion cells).
-active (energy using) process.
assimilates
products of photosynthesis
lignification
deposition of lignin in cell walls, provides strength and water proofing
bordered pits
gaps in cell walls that occur when lignification is incomplete.
pits in adjacent vessels are aligned so water can flow between them.
cohesion
the bonding of water molecules through hydrogen bonds.
adhesion
weak bonds between water molecules and walls of xylem vessel.
sieve tube elements
-cells lines up to form sieve tubes.
-no nucleus & little cytoplasm (lots of space for mass flow of sap (sucrose) to move along phloem).
-perforations (sieve plates) at ends allow sap to move from one element to another.
companion cells
-found in between sieve tubes.
-large nucleus & dense cytoplasm containing lots of mitochondria.
-acts as a site of aerobic respiration, produces ATP used for active processes of plant.
sources
anywhere assimilates are loaded into plant
sinks
structures that are in need of assimilates.
plasmodesmata
thin strands of cytoplasm that connects companion cells to sieve tube elements, and allows flow of assimilates between the cells.
root cortex
series of plant cells that extend inwards from epidermis (outer layer of plant)
symplastic pathway
water travels through cytoplasm of plant cells
apoplastic pathway
water travels freely through cell walls, without passing through plasma membrane
vascular pathway
water travels through vacuoles
medulla
central part of stem containing xylem
endodermis
cylinder of living cells that form final boundary between root cortex and medulla.
transpiration
loss of water vapour from a plant through leaves.
transpiration pull
water vapour that is lost must be constantly replaced by water in the xylem
tension
transmitted pulling force