Week 11 Flashcards
how plants harvest energy
from sunlight
how plants harvest mineral nutrients
from soil
Root system
anchors plants
absorbs water and minerals
stores photosynthetic products
root system branching
increases surface area
shoot system
leaves
stem
leaves
main photosynthetic organs
stems
hold leaves up in sunlight
connect roots and leaves
plant vegetative organs
root and shoot system
monocots
clade of angiosperm
narrow leaved plants like grasses
eudicots
clade of angiosperm
generally broaded leaved plants
processes that develop all organisms
determination
differentation
morphogenesis
growth
determination
commitment
differentiation
specialisation of cells
morphogenesis
organisation of cells into tissues and organs
plant development - influences
meristems
cell walls
totipotency of most cels
meristems
tissue made up of undifferentiated actively dividing cells
can produce new roots, stems, leaves and flower throughout plants life, enabling continuous growth
cell wall
rigid extracellular matrix
cells cant move
Morphogenesis
occurs through changes in the plane of cell division at cytokinesis
changes direction of tissue growth
Two main growth patterns established in embryo
apical basal
radial
apical basal
arrangement of cells and tissues along main axis
radial
concentric arrangement of tissue systems
first division of zygote
uneven
sets up apical basal and polarity
smaller cell
becomes embryo
larger cell
becomes supporting structures
tissue
organised group of cells with similar features that work together
3 types of plant tissue
dermal
vascular
ground
Dermal tissue system
forms epidermis
usually one cell layer
the epidermis cells differentiate
stomata
trichomes
root hairs
stomata
pores for gas exchange
trichomes
leaf hairs
protect from herbivores and damaging solar radiation
root hairs
increase root surface area
cuticle
waxy substance
limits water loss
reflects solar radiation
acts as pathogen barrier
ground tissue system
between dermal and vascular tissue
contain 3 types of cells
3 types of ground cells
parenchyma
collenchyma
sclerenchyma
parenchyma cells
most abundant
large vacuoles and thin cell walls
photosynthesise
store protein and starch
Collenchyma
elongated
thich cell walls
provide support
sclerenchyma
very thich walls reinforced with lignin
undergo programmed cell death
2 types
2 types of sclerenchyma
fibers
sclereids
fibers
elongate
provide rigid support
sclereids
various shapes
pack together densely
vascular tissue system
the transport system
contains xylem and pholem
xylem
carries water and minerals from roots to rest of plant
2 cell types
2 types of xylem
tracheids
vessel elements
tracheids
pits in cell walls that allow movement of water
vessel elements
form pipeline
phloem
moves carbs from production sites to storage and sites of usage
2 types
2 types of phloem
sieve tube elements
companion cells
sieve tube elements
meet end to end, forming sieve tubes
lose most of cellular components
companion cells
connected to sieve tubes by plasmodesmata
perform many metabolic functions
determinate of plants
growth
ceases when adult state is reached
indeterminate of plants
roots and shoots
open ended process that can be life long
primary growth
lengthening of shoots and roots
apical meristems
secondary growth
increase in thickness
lateral meristems
meristem cells
after division, one daugther cell differentiates while the other stays as it is
root apical meristems
daughter cells on root tip form root cap
root cap
protects root as it pushes through soil
cells detect garvity and control downward growth
apical meristems
produce primary meristems
protoderm
ground meristem
procambium
root protoderm
produces epidermis
root ground meristem
produces cortex, with parenchyma cells and endodermis
endodermal cells
have waterproof suberin in cell walls and control movement of water into vascular system
root procambium
produce vascular cylinder (stele) which is made of pericycle xylem and phloem
pericycle functions
give rise to lateral roots
give rise to lateral meristems, contributing to secondary growth
export nutrients
monocots root system
fibrous
roots are equal in diameter
adventitious roots
adventitious roots
arise from stem tissues above initial root
shoot apical meristem
lays down at beginnings of leaf
leaf primordia
bulges that leaves arise from
bud primordia
form above leaf primordia
initiate new shoots
shoot protoderm
gives rise to shoot epidermis
shoot ground meristem
gives rise to shoot cortex
shoot procambium
gives rise to shoot vascular system
leaves
determinate
flat blade attached to plant stem by petiole in eudicots
petioles
allow leaves to adjust orientation
perpendicular
to suns rays to maximise light
parallel
avoid overheating
leaf anatomy
adapted to carry out photosynthesis
gas exchange
limit evaporative water loss
export products of photosynthesis
mesophyll
photosynthetic parenchyma
have air spaces that allows co2 to diffuse
taproots
function in storage
prop roots
help support shoot
eudicot secondary growth
from
vascular cambium
cork cambium
vascular cambium
produces secondary xylem (wood) and phloem (inner bark)
cork cambium
produces waxy walled protective cells
monocots secondary growth
dont have
essential elements
absence disrupts plant growth and reproduction
macronutrients
nitrogen phosphorus potassium sulfur calcium magnesium
micronutrients
iron chlorine copper nickel boron zinc
soil
provides anchorage
mineral nutrients
o2 for root respiration
soil living components
plant roots
bacteria, fungi and other animals
soil non living components
rock fragments water mineral nutrients air spaces dead organic matter
horizons
horizontal layers that soil develops in
topsoil (A)
contains most o soils living and dead organic matter
subsoil (B)
accumulates materials from topsoil and parent rock
parent rock (C)`
from which soil arises
nitrogen fixation
change n2 to NH3
hemiparasites
can photosynthesise
get water and mineral nutrients from living plants
holoparasites
no photosynthesis
water potential
tendency of a solution to take up water from pure water across membrane
aquaporins
membrane channels that water diffuses through
regulates osmosis
proton pump
uses energy from atp to move protons out of cell against a proton concentration gradient
cations movement
move into cell by faciliated diffusion
anions movement
into cell by coupling movement with h+
apoplast
water and ions move through cell walls and intracellular spaces
a continuous meshwork
water and solutes never cross membrane
symplast
water and ions move through continuos cytoplasm of living cells connected by plasmodesmata
transpiration cohesion tension
how xylem moves water up trees
transpiration
evaporation of water from mesophyll cells in the leaves and diffuses out stomata
cohesion
of water molecules in xylem sap due to hydrogen bonding
tension
of xylem sap resulting from transpiration
stomata
pores in epidermis
regulates gas exchange by opening and closing guard cells
stomata at day
open to allow co2 in
stomata at night
closes to conserve water
guard cells - light reaction
absorb light to activate proton pump
translocation
movement of solutes in the phloem from source to sink
source
organ that produces or stores carbs
sink
organ that consumes carbs for growth and storage
loading
transport of solutes from sources into sieve tubes
unloading
transport of solutes from sieve tubes to sinks
apoplastic pathway
solutes enter the apoplast and molecules are actively transported into cells
solutes can be regulated
symplastic pathway
solutes remain in the symplast at all times
no membranes are crossed
monocot stem
vascular tissue scattered
eudicot stem
vascular tissue arranged in concentric circles
monocot leaf ventation
veins usually parallel
eudicot leaf ventation
veins form network
monocot root system
fibrous
no main root
eudicot root system
taproot (main root) usually present
monocot flowers
usually in multiples of 3
eudicot flowers
usually in multiples of 4 or 5
monocot pollen
pollen grain with single furrow or pore
eudicot pollen
pollen grain with 3 furrows or pores
solute potential
solutes reduce the concentration of free water
more solutes the lower the water potential
increases cell tendency to take up water
pressure potential
as plants take up water they swell
cell wall resists swollen and results in turgor pressure which decreases the tendency for cell to evaporate
