Summary: Monocot vs. dicot

Summary: Monocot vs. dicot
Monocots
showy flowered non-showy flowered
commelinids
The angiosperms are
Lily group
the magnoliids, the monocots
Ginger group
and the eudicots.
Eudicots
Grass group
Alismatales
Palms
Magnoliids
Caryophyllids
Laurels
Magnolias
Peperomias
Pipe vines
Star anise group
single cotyledon
tricolpate
pollen
Water lilies
Amborella
Living gymnosperms
Gnetophytes
Conifers
vessels
double fertilization
fruit
flowers
Ginkgo
Cycads
Unknown gymnosperms
Rosids
Asterids
Proteales
Ranunculales
Angiosperm characteristics
Basal
Derived
Leaf retention
evergreen
deciduous
Xylem vessels
absent
present
Rays
all narrow/tall
several types
Flowers
parts present?
complete
incomplete/
imperfect
part number
arrangement
symmetry
ovary position
fusion of parts
pollination
fruit/seed dispersal
many
spiral
radial
superior
not fused
wind or beetles
wind
few: 3,4,5
whorls
bilateral
inferior
fused
many
many
?
?
?
?
Eudicots defined by a single
character: tricolpate pollen
Caryophyllids
11,000 species (7% of flowering plant)
Three main families: Aizoaceae (ice plants)
Cactaceae (cacti)
Caryophyllaceae (carnations)
Other families:
Droseraceae - Dionea (flytrap), Drosera (sundew)
Nepenthaceae - Nepenthes (pitcher plant)
betanin
Distinctive characteristic is presence of red and yellow pigment group betalains
most dramatically demonstrated by red beets.
Most other flowering plants have anthocyanins in their flowers, caryophyllids have betalains
Caryophyllids lack petals, they have modified sepals that look like petals (some have modified stamens
that look like petals).
They have differences in sieve tube plastids that differentiate Caryophyllids from other taxa.
Caryophyllids
Aizoaceae - ice plant Cactaceae - cacti
Caryophyllaceae carnations
Caryophyllids
Nepenthes - pitcher plant
Dionea - Venus flytrap
Rosids: 70,000 species - on of the largest
group of angiosperms
Characteristic Features
- two or more whorls of stamens
- well-developed stipules
-  anthers articulated (jointed)
- embryo relatively large compared to
seed size
contains all angiosperms that form
symbiotic associations with nitrogen-fixing bacteria
in root nodules.
Alfalfa nodules
stipules
Rosids: includes legumes
such as Vicia
Rosids:
spurges
roses
Rosids:
cucurbits
Rosids:
cotton
Asterids, 90,000 species - the largest group of angiosperms
Characteristic features of Asterids
- petals fused = sympetalous
- stamen number usually less than the petal number
- ovules with a single integument (rosids have a
double integument)
- thin-walled megasporangium
sympetalous
Asterids:
Solanaceae
tomato
potato
tobacco
peppers
corolla
ovary
stigma style
anthers
filament
calyx
calyx
fruit
calyx
locule
placenta
seeds
ovary wall
Asterids
Sages (Salvia)
stigma
anther
style
stamen
calyx
stigma
style
anther
corolla
calyx
Asterids
Carrot family Apiaceae
Reproductive strategies
Benefits to self pollination
In extreme environments or with sparse populations self pollination
allows reproduction
Good for pioneer species - no neighboring plants required
Saves energy on pollen, less pollen production necessary in selfing
plants
Benefits of cross pollination:
Produces variable offspring, creating diversity and variation among
populations (shuffling of genes). Variation is required for natural selection
to occur.
Flowers with all four sets of floral parts are complete flowers
Flowers missing one or more parts are said to be incomplete
Male (only) flowers are called staminate
Female (only) flowers are called pistillate
Flowers with male and female parts are called perfect flowers
filament
anther
Meiosis
pollen
sac
tapetum
anther
Pollen sac
microsporocyte two-cell stage four-cell stage
filament
germinated
pollen grain
Mitosis
tube cell
generative cell
pollen tube
sperm cells
stamen
tube nucleus
tube nucleus
pollen grain
(male gametophyte)
microspores
Angiosperm
lifecycle
Flowering plants exhibit
alternation of
generations. The large,
familiar flowering plant
is the diploid
sporophyte, while the
haploid gametophyte
stages are microscopic.
The unique feature
about the life cycle of
flowering plants is a
double fertilization that
produces a diploid
zygote and a triploid
endosperm or nutritive
tissue.!
Wind pollinated
Gymnosperms and some flowering plants (grasses, trees) use wind pollination.
Flowers are small, grouped together
Not a very efficient method
Animal pollinators
Insects – bees, wasps, flies, butterflies, moths
Birds – hummingbirds, honey creepers
Mammals – bats, mice, monkeys
Some reptiles and amphibians
Humans (apple pollination in China) some home garden plants
Coevolution – interactions between two different species as selective forces on
each other, resulting in adaptations that increase their interdependency.
Animal-flowering plant interaction is a classic example of coevolution:
Plants evolve elaborate methods to attract animal pollinators - benefit from
cross pollination.
Animals evolved specialized body parts and behaviors that aid plant pollination benefit by getting food (nectar and pollen).
Bees – are the most important flower pollinators
They live on the nectar and feed
larvae, also eat the pollen.
Bees are guided by sight and
smell
They see yellow and blue colors,
also ultraviolet light (not red)
Bee collecting pollen
Moths and Butterflies also guided by sight and smell
Butterflies can see red and orange flowers
Flowers pollinated by moths and butterflies are usually shaped as a long
tube because of insect’s proboscis
Moth-pollinated flowers are usually white or pale, with sweet, strong odor
– for night pollination.
Flies and Beetles
Flies like flowers that smell like dung or rotten meat.
Lay their eggs there, but larvae die due to lack of food
Beetles pollinate flowers that are dull in color, but have very strong odor
Rafflesia arnoldii - the corpse flower is a parasitic
plant that produces the largest flower known
(up to 1 meter in diameter). It smells like rotting
meat. Each flower produces one seed.
Beetles feeding on nectar and pollinating flowers
Birds
Bird-pollinated flowers are yellow or red
Birds do not have a good sense of smell, so birdpollinated flowers usually have little odor.
Flowers provide fluid nectar in greater quantities than
insect - pollinated flowers
Hummingbird-pollinated flowers usually have long,
tubular corolla
Pollen of bird-pollinated flowers is large and sticky
Bird feeding on flower
Mammals
Bats pollinate at night - flowers are usually white
and open at night
Mouse-pollinated flowers open at night.
Bats feeding on cactus flowers
Rewards for pollinators
Nectar – a sugary solution produced in flower glands called nectaries
Nectar concentration matches energy requirements of the pollinator:
bird- and bee-pollinated flowers have different sugar conc.
Pollen – is high in protein, some bees and beetles eat it.
Attracting pollinators
Visual cues (color)
Scent cues (odor)
Some plants take advantage of the sex
drive of certain insects…
Certain orchids look like female wasps,
and even smell like them!
Next time: More plant reproduction Ch. 9