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The more advanced forms of reproduction and nutrients transport - Coggle…
The more advanced forms of reproduction and nutrients transport
Flowering plants
Origins
first flowers 125 mya, came around much later than the first plants on land.
angiosperms; fruiting plants.
ancestral flower
based on molecular data
bisexual
androecium - 2+ whorls of anthers
gynoecium - 5+ carpels
radial symmetry
multiple whorls of petals
first flower fossil
archaefructus sinensis
likely herbaceous and aquatic
124.6 BYA
most primitive extant
amborellaceae
amborella, only line in this group
dioecious
male plants
female plants
it's a shrub, kinda
new caledonia
anther looks like a leaf folded over. this makes sense.
general trends through time
flowers indefinite in number of parts, so flowers have few parts that are definite in number.
floral axis shortened
original spirals arrange no longer evident in derived flowers
floral parts ofren fused, more complex structures
ovary becomes inferior
perianth has become differentiated in distinct calyx and corolla
radial symmetry, irregularity
derived flowers are bilaterally symmetrical
#
Parts
perfect, complete flower
a flower is a stem with leaf-like structures
complete flowers have all 4 floral appendages
sepals - sterile
outermost floral appendage
modified leaves that surround maturing flower parts
protect the flower bud as it develops
may be colorful on occasion
altogether, they are called the calyx.
petals - sterile
above sepals and receptacle.
leaf-like, but not pigmented with chlorophyll.
attract pollinators
collectively, are a corolla.
sepals and petals, collectively, are the perianth.
not present in wind-pollinated species.
stamens - male FX
above petals
collectively called the androecium
diploid anther cells undergo meiosis to produce 4 microspores
microspores undergo mitosis to form a resistant cell wall
microgametophyte - pollen grains
carpels - female FX
modified megasporophyll
stigma, style, and ovary
stigma catches pollen
style elongates the organ
ovary is where megaspores are produced
within ovary are placentae that bear the ovules
after fertilization of egg, ovule turns into a seed.
ovary wall becomes fruit.
incomplete flowers lack at least one floral appendage.
Modification
carpel position
whorl inserted relative to ovary.
superior - carpel above
inferior
receptacle surrounds carpel
carpel below
perianth and stamen insertion
hypogynous
perianth and stamens on receptacle beneath ovary
example: lillies
epigynous
perianth and stamens above ovary
example: apple flower
perigynous
perianth and stamens adnate to calyx
example: cherry flower
imperfect flowers
lacks a whorl of organs
hermaphroditic = perfect
monoecious = male flowers and female flowers present on the same plant
dioecious = male flowers and female flowers present on separate plants
display variation
inflorescence
taxonomic importance
various ways to ensure cross-pollination
pollination syndromes
syndromes: trait modification
major traits
color
some colors are more attractive than others
colors require resources; they are omitted when not necessary.
some are in UV spectrum
smell, organic volatiles
signal to pollinators
sometimes use own preferences and sexual pheromones
:some common chemicals
benzaldehyde (almond)
linalool (lavender)
beta ocimene (green)
limonene (citrus)
may have scent glands
bloom time
diurnal
daytime
nocturnal
night time
shape
floral symmetry
actinomorphic, radial symmetry
:sunflower:
zygomorphic, irregular and bilateral
rewards, such as nectar
nectar
yum yums for everyone
pollen
yum yums for ants
oil
bee perfume.
they're all to attract pollinators.
major syndromes
abiotic
anemophily, wind
no bright colors, nectar, or special odors
small, most don't have petals
stamens and stigmas exposed to air currents
pollen smooth, light, easily airborne
stigma feathery to catch pollen from wind
hydrophily, water
rare.
lots and lots of pollen, small flowers
long filaments for pollen transport on surface of water
oblong, heavier pollen for submarine transport
biotic
melittophily, bee :bee:
full of nectar
sweetly aromatic or minty in fragrance
open in daytime; diuretic
#
brightly colored petals, usually blue or yellow (bees can't see red)
have landing platforms
usually bilaterally symmetrical
#
flowers often tubular
psychophily, butterfly :butterfly:
in clusters, and provide landing platforms
red, yellow, orange
diurnal
lots of nectar, but it's deeply hidden.
nectar guides
may be clusters of small flowers
phalenophily, moth
many night pollinated species, nocturnal
heavy scent
tubular corollas
white
myophily, sapromyophily, fly
pale and dull to dark brown or purple.
sometimes flecked with translucent patches
putrid odor
nectar guides not present.
flowers are funnel-like, or complex flytraps
sapromyophily, for carrion mimics.
produce pollen
orinthophily, birds :bird:
tubular and have petals that are recurved to be out of the birds' way.
tubes, funnels, cups
odorless (birds can't smell nuthin)
strong supports for perching
brightly colored, red yellow and orange.
diurnal
modest about pollen, designed to dust the birds' heads and backs with pollen as the bird gets nectar.
PROLIFIC nectar producers, deeply hidden nectar
chiropterophily, bats :bat:
large in size, 1 to 3.5 inches
pale or white in color
very fragrant, fermenting or fruit-like odor.
copious dilute nectar
open at night, nocturnal
watching them eat was so funny.
cantharphily, beetle :beetle:
bowl-shaped with sexual organs exposed
strong fruity smell
moderate nectar producers
diurnal
may be large solitary flowers, eg magnolia or pond lillies.)
may be clusters of small flowers
deception
may look like pollinator
may smell like pollinator
uses trickery
usually no reward. :cry:
saprophily included!
Fruits
fruit formation
ovary sometimes with other proportions of flower, or inflorescence develops into fruit
ovary wall
pericarp
thickens and differentiations
exocarp
fruit skin
mesocarp
part that we eat
endocarp
the protective layer surrounding the seed(s)
Accessory fruit
any fruit with accessory tissue (tissue besides the ovary is included in the fruit
can be simple, aggregate, or multiple
parthenocarpic fruit
fruit development
without fertilization
without seed development
banana, seedless watermelon
simple fruits
single carpel
2+ united carpels
examples:
bean
cherry
tomato
major fleshy types
berries :tomato:
drupes :peach:
pomes :apple:
major dry types
dehiscent
indehiscent
aggregate fruits
apocarpous gynoecium
carpel retains its identity in mature state
examples
magnolias
raspberries
strawberries
multiple fruits
derived from an inflorescence
combined gynoecia of many flowers
examples
fig
mulberry
pineapple
Transport
Cohesion-tension theory
transpiration stream
#
water movement from soil to atmosphere.
water enters root hairs through osmosis due to hypotonic soil solution
hypotonic to hypertonic
root hairs increaase surface area
water passes through endodermis, filtering solution, which prevents embolism and infection.
casparian strip of root endodermis is good about this.
forces symplastic movement
embolism = air pocket
makes tracheary element impossible to use.
water pulled up through stem under tension, in an unbroken column
as water diffuses out of xylem in leaves, cohesive force pulls water up thru xylem all the way from the roots.
water in the uppermost tracheary elements must lift the weight of the entire water column
tension is placed on these molecules, and consequently, pressure potential is negative.
straw.
water remains unbroken due to cohesion of water molecules
due to water polarity
adhesion along cell walls fights gravity
the taller the plant, the more powerful and negative the water gradient must be.
follows high to low moisture levels.
less negative to more negative water potential.
plants lose water to dry atmosphere.
happens through stomata.
creates water potential differential.
stomata open shortly after daybreak
closes during stress
closes at night
equilibrium with soil. reduces stress. Dr. Dudley sees this as them sleeping, which I think is adorable and I like that a lot.
once stomata open, water potential gradient forms from mesophyll cells all the way back to xylem.
draws water from vein
water evaporates from intercellular spaces.
starts domino effect of water potentials.
more negative the higher into the atmosphere you go.
Pressure flow
from source to sink
sources are leaves that have chloroplasts.
transport assimilate from where it's made,
materials moved to sinks
actively growing areas, like apical meristem
storage areas
fruits are the strongest sinks.
steps
assimilate loaded into sieve tube elements with the help of companion cells from source.
sugars transported as sucrose
active transport into sieve element, done by companion cell
decreases water potential of the sieve tube element.
increases osmotic concentration, decreases water potential in sieve tube
creates a water potential gradient between sieve tube elements and surrounding cells,
water enters sieve tube from xylem due to water potential differential, creating turgor pressure
this is why phloem is always close to xylem
xylem has higher water potential than phloem
water moves from less negative water potential to more negative water potential
#
photosynthate moves via bulk flow to nearest/strongest sink and is unloaded.
2 more items...
water movement - no energy
photosynthate movement - yes energy
water flow
water free energy
transpiration depends on this
potential for water to move
due to its polarity
attracted to other substances
potential is lower when surrounded by ions.
water moves from hypotonic to areas that are hypertonic.
transpiration
moves water from soil to atmosphere
major input of water cycle
evaporation of water from stomata
reason for rain.
plant sweat.
huge amount of water goes through an individual plant alonne.
water potential
Water potential
Based on the free energy of water.
Water moves from less negative water potential to areas of more negative water potential.
Higher pressure pulls water out of the plant. You cannot pull too much or you will cause boiling.
Peaks in water potential at night, dip during mid-day.
There is a permanent wilting point in which after a certain amount of water deprivation, nothing can save the plant.
Components of water potential
Ψp = pressure potential
If water is under pressure, both pressure potential and water potential increase
Effect that turgor pressure has on Ψ
Hydrostatic pressure exerted on water in a cell
In turgid plant cells positive value
Xylem cells negative due to cohesion
Water at atmospheric pressure has a pressure potential of zero.
Ψ(pi) = osmotic potential
Effect that solutes have on Ψ
Adding salutes decreases water's free energy, so Ψ(pi) is always negative
Ψm = matric potential
Adhesion to structured such as cell wals, membranes, and soil particles.
Adhesion can only decrease water's free energy, so Ψm is always negative.
Significant only outside living systems in very dry soils.
Seeds
Origins
earliest seed
Elkinsia polymorpha
4 - 5 lobes fused basal 3rd.
360 MYA
late devonian
primitive ovule
longer, lobate integuments
free from nucellus
moresnetia zalesskyi
8 to 10 lobes fused at chalaza and widely separates.
360 MYA
enclosed ovule
complete enclosure of microsporangium within integument.
increased protection against
dessication
herbivory
eg. stamnostoma huttonense
352 MYA
gnetopsisseliptica.
cupule tissue forms nucellus.
ovule evolution
evolved from shoot apex
gymnosperm nucellus apex similar to shoot apex.
similar genes
innovations
heterospory
protection via integuments
#
pollen capture.
pollen chamber and micropyle.
nucellus
Steps
evolution of the ovule
heterospory
megaspores
microspores
found in some non-seed plants.
megasporangium enclosed in integument
reduce # of megasporocytes/megasporangium to 1
megasporocyte
reduced to 1 per megasporangium.
survuval of 1 megaspore
retention of megaspores within megasporangium.
5 more items...
megasporocyte undergoes meiosis
1 more item...
3 megaspores degenerate
1 more item...
megaspore mother cell
first integument telomes
second integument phyllad origin
Microgametophyte
multicellular haploid individual.
gametophyte dominant stage in early land plants. reduced over time.
reduction
angiosperm, 3 celled
tube cell
generative cell
microspore within microsporangium
mitosis within microspore wall
endosporic male gametophyte = pollen grain
#
antheridia
sperm development in antheridia
sperm rely on water for swimming to archegonia.
pollen
microgametophyte type
exine protects from desiccation.
dispersal does not require water.
some have air bladders which aids in wind dispersal.
hautoria pollen tubes
tubes feeding on nucellus, provide nutrition to developing sperm
process can be extremely time consuming.
Ovule diversity
gymnosperm
megasporangium is nutritious tissue, and nucellus.
nested doll layout.
integument, megaspore wall, megasporangium, archegonium, eggs.
pine ovule
ovule on megasporophyll.
1 microsporocyte
pollen chamber
nested doll layout :
integument, nucellus, megaspore wall, megagametophyte, archegonium, eggs
angiosperm ovule
2 integuments
megasporangium = nucellus
megasporocyte reduced to 1
megaspore reduced to one and retained.
megagametophyte = egg sac
eg. lily ovule
mitosis forms megagametophyte
comparison between gymnosperms and angiosperms
gymnosperm
1 integument
angiosperm
2 integuments
additional protection from ovary wall
double fertilization
both
single sporocyte
single megaspore
the actual seeds
permits dormancy for the embryo.
advantages
increased independence from free water production.
enabled colonization of drier land habitats.
allows for advanced reproductive traits.
embryo dormancy and size allows for greater chance of survival.
gymnosperm
pine example
some fleshy outer layer (aril)
several cotyledons.
integument is seed coat.
double fertilization of angiosperms
#
pollen tube grows down style
generative cell divides into two sperm
pollen tube ruptures inside synergid, releasing sperm
1 sperm fuses with egg
2n diploid
zygote
1 sperm fuses with polar nuclei
3n triploid
endosperm
grains and popcorn is endosperm.
bread is also endosperm.
made to nourish the reproductive tissue.
monocot
one cotyledon
integument becomes seed coat
eg. corn
large amount of endosperm
#
eudicot
eg bean.
2 cotyledons
lots of endosperm, like monocot
integuments also become seed coat.
