Angiosperms - Flowering Plants
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Land Plant Evolution: Land Plant Evolution:
Algae to Angiosperms Algae to Angiosperms
The greatest adaptive radiation . . .
• is the largest radiation of
plants
• involves series of dramatic
adaptations to the problem of
life on land and being non-
motile
• exhibits successive rounds
of speciation and subsequent
extinction
• sets the stage for the
development of a land-based
ecosystem with fungi and
animals
Angiosperms - Flowering Plants Fungi?
• Fungi collectively are not a natural group
Angiosperms focus of the course
• More closely related to animals than to plants
• comprise the phylum Magnoliophyta
• contains majority of plant diversity take Botany 332 – spring 2019
What are the non-angiosperm land plants?
• DNA evidence has clarified much but not all
of the relationships of other phyla
See first pages of Chpts 1 & Chpts 3-4 for
more detail (Plant Systematics, 2nd ed.)
1Fungi? Charales - stoneworts
• Green algal lineage take Botany 330 – fall 2019
Recent view of • Closest relatives to land plants
eukaryotic
relationships
• root is in microbes with
fungi/animals/plants
forming a crown radiation
Fungi are here Green Plants are here
we are here
Charales - stoneworts Extinct Land Plants - the first plants
Ordovician Period (505 - 440 mya)
• Green algal lineage take Botany 330 – fall 2019
• First evidence of land life at 460 mya
• Closest relatives to land plants
Microfossils of spores
with sporopollenin
(degradation resistant
material like lignin) and
similar to modern day
bryophytes such as
liverworts
Starry stonewort
Nitellopsis obtusa L. Found worldwide in shales that were
deposited at the marine-terrestrial interface
Wisconsin’s latest (and
greatest?) lake invasive
2bryophytes bryophytes
• earliest land plants - non vascular
• gametophyte dominant, 16000 species
• 3 lineages — they are not a natural group
hornworts mosses mosses
Liverworts - Marchantiophyta
Mosses - Bryophyta
Hornworts -
Anthoceratophyta
liverworts liverworts
Extinct Land Plants - first vascular plants Lycopodiophyta - club mosses
Early Devonian Period (410 - 390 mya) • 3 families, 1150 species
Rhynia seen in the early Devonian (Rhynie • sporophyte dominant, vascular, free sporing
Chert fossil) is one of first vascular plants • they are sister to all other vascular plants
20 cm tall, no roots, no leaves, primitive
vascular tissue
Lycopodium -
club mosses
Isoetes - quillworts Selaginella - spike mosses
3Extinct Land Plants - the first ferns Polypodiophyta - ferns
Late Devonian Period (390 - 360 mya) • 11000 species (or called “Monilophyta”)
• immense variation in habit and habitat
• spores produced in specialized sporangia
• need a lot of systematic work - tropics!
First true ferns [Protopteridium] - free sporing
with complex sporangia & megaphylls
Polypodiophyta - ferns Polypodiophyta - ferns
• includes the horsetails as unusual ferns! • includes the strange whisk ferns!
• 15 species in Equisetum • 6 species in 2 genera
• vascular plants, reduced leaves, terminal • vascular plants, leafless green stemmed,
sporangia lateral sporangia
Psilotum habit Psilotum branch Psilotum sporangia
4Extinct Land Plants - the seed plants Extinct Land Plants – first gymnosperms
Late Devonian Period (390 - 360 mya) Permian Period (286 - 245 mya)
First “seeds” - “seed ferns” [Archaeosperma]
Plants fern-like with dissected compound leaves,
but produce naked seeds (embryo within • Big trees with net-veined
protective coverings)
leaves
• Seed bearing (derived from
female gametophyte) and
pollen forming (from male
gametophyte)
Pinophyta - gymnosperms Pinophyta - gymnosperms
• 870 species • 870 species
• seed plants but seeds naked • seed plants but seeds naked
• often divided into 4 phyla conifers • often divided into 4 phyla
• is one closer to angiosperms? • is one closer to angiosperms?
cycads
pine spruce juniper male strobilus female strobili
5Pinophyta - gymnosperms Pinophyta - gymnosperms
• 870 species • 870 species
• seed plants but seeds naked • seed plants but seeds naked
• often divided into 4 phyla • often divided into 4 phyla
• is one closer to angiosperms? • is one closer to angiosperms?
gnetophytes
mature seeds
ginkgo Gnetum
Ephedra
male strobili
Welwitschia mirabilis
Extinct Land Plants – first flowering plants Magnoliophyta - angiosperms
Cretaceous Period (146 - 65 mya)
Near the Jurassic/Cretaceous border, the
first Angiosperms are seen
• 275,000 + species (400,000 ?)
• seed plants with seeds encased in
ovary
Triassic • flowers a “key innovation”
Archaefructus
6Angiosperms - Flowering Plants Angiosperms - Flowering Plants
• tremendous adaptive radiation on • tremendous adaptive radiation on
land (and back into water) land (and back into water)
• Eucalyptus regnans
(Myrtaceae) over 100m tall and
19m dbh
Eucalyptus regnans
(Myrtaceae) -Tasmania
Angiosperms - Flowering Plants Angiosperms - Flowering Plants
• tremendous adaptive radiation on • tremendous adaptive radiation on
land (and back into water) land (and back into water)
• Wolffia microscopica • Wolffia microscopica
(Araceae) less than 1mm long (Araceae) less than 1mm long
0.1 mm
• Amorphophallus titanum
(Araceae) over 2 m tall
7Angiosperms - Flowering Plants Angiosperms - Flowering Plants
• tremendous adaptive radiation on • tremendous adaptive radiation on
land (and back into water) land (and back into water)
• largest inflorescence • largest numbers of flowers —
Amorphophallus titanum (Araceae) Corypha palm
Angiosperms - Flowering Plants Angiosperms - Flowering Plants
• tremendous adaptive radiation on
land (and back into water)
• largest flower: Rafflesia arnoldii Magnoliophyta classification
(Rafflesiaceae) from New Guinea,
up to 1m across and 20lbs • previously divided into two
classes — dicots and monocots
• artificial!
• we will use Angiosperm
Phylogeny Group (APG III)
classification system of 2009
8Angiosperms or Flowering Plants The Flower — Why Important?
the Phylum Magnoliophyta The Flower: most significant feature of angiosperms
1. unlike anything else in other plants & extremely
Today & Monday: overview of the morphology variable & co-evolved with animals
and evolution of the flower – optionally read first 2. floral features used in describing and id’ing
part of Chpt. 6 in Plant Systematics, 2nd ed. – 3. plant specimens (herbarium) must include flowers or
available at Canvas/Learn@UW derived features
4. classification of angiosperms relies on flowers
Lab next two weeks: (1) vegetative features
& conifers – 1st half of Chpt 9 in Plant Calochortus - fairy lanterns & mariposas (images: T. Givnish)
Systematics; (2) finish overview of flower
and examine floral, fruit, & inflorescence
diversity – 2nd half of Chpt. 9
The Flower — What is it? The Flower — What is it?
• “foliar theory” of flower - J.W.
• specialized shoot = stem +
von Goethe in “Attempt to Interpret
leaves (folia)
the Metamorphosis of Plants”
(1790)
• shoot is highly modified and
determinate (ceased to grow)
from Schleiden 1855
9The Flower — What is it? The Flower — What is it?
• developmental/evolutionary origin of the • developmental/evolutionary origin of the
flower still debated flower still debated
1. Euanthial theory - (foliar
theory) - single shoot, cone
or strobilus
anthers (male)
? ovules (female)
2. Pseudanthial theory -
compound shoot or cone,
different shoots “coalesce”
or “condense”
? ?
The Flower — What is it? The Flower — What is it?
• thus, a flower is a specialized shoot that: The ‘ABC’ model of
floral part identity
1. is determinate (vs. indeterminate)
2. has a modified stem with
B
compressed internodes A C
sepals petals stamens carpels
3. possesses modified leaves with
various functions, these determined
by gene arrays (e.g., ABC model)
10The Flower — What is it? The Flower — What is it?
The evolution of the ‘ABC’ • thus, a flower is a specialized shoot that:
model of floral part identity
The Plant Cell, 2010
1. is determinate (vs. indeterminate)
2. has a modified stem with
compressed internodes
3. possesses modified leaves with
various functions, these determined
by gene arrays (e.g., ABC model)
4. often clustered in an inflorescence
(larger branch)
The Flower The Flower
read chpt 9 in Plant Systematics!
• 1st half deals with
vegetative features - we will
cover in lab 2 this week
• 2nd half deals with
flowers/fruits - lab 3 next
week
1. Peduncle: floral stalk, the stem
supporting the flower; sometimes
referred to as the pedicel
11The Flower The Flower
2. Receptacle: modified floral stem or 3. Sepal: the outer whorl of leaves,
axis from which arise the floral green and protective; collectively
appendages or modified leaves called the calyx (CA)
The Flower The Flower
4. Petal: the second whorl of leaves, 5. Perianth: collective term for Tepals if both similar or if only
typically brightly colored, attracting sepals and petals (P) one reduced set (sepals)
pollinators; collectively called the
corolla (CO)
12The Flower The Flower
8. Stamen: the male structure of collectively, stamens are the 6. Filament: slender stalk of the stamen supporting
flower comprising filament and androecium (= ‘house of the anther; permits exsertion of anther with pollen
anther males’) (A) out of flower
The Flower The Flower
Nuphar
7. Anther: fertile portion of stamen that
dehisces to release pollen grains; composed of
anther sacs • stamens can be leaf-like in primitive angiosperms!
13The Flower The Flower
Nectaries often near base of stamens - 13. Pistil: flask-shaped, female • all pistils (1 or more) are
produce nectar reward for visitors structure comprising three main referred to as the gynoecium
who will move pollen (‘pollinators’) parts – often referred to as carpel(s) (= ‘house of females’) (G)
The Flower The Flower
13. Pistil: flask-shaped, female 12. Stigma: receptive portion 13. Pistil: flask-shaped, female 11. Style: slender stalk of pistil
structure comprising three main at top of style that receives structure comprising three main above ovary that the pollen tubes
parts – often referred to as carpel(s) and recognizes pollen parts – often referred to as carpel(s) must pass through to reach eggs
in ovules
14The Flower The Flower
13. Pistil: flask-shaped, female 9. Ovary: basal portion of pistil 13. Pistil: flask-shaped, female 10. Ovules: fertile portions of pistil
structure comprising three main that contains ovules; at maturity structure comprising three main that contain a female gametophyte
parts – often referred to as carpel(s) becomes fruit with seeds parts – often referred to as carpel(s) (embryo sac); develop into seeds
after fertilization
The Flower The Flower
Study of the pollen, its transfer, and movement
Pollination biology Pistil vs. carpel
down the style
How do you know?
3 examples
Carpels not fused
1. Monocarpic
2. Apocarpic
Carpels fused
3. Syncarpic
15The Flower The Flower
When pistil = carpel When pistil = carpel
1. Monocarpic – when flower has only 1 pistil
legume
flower
1 floral ‘leaf’ in gynoecium Folded ‘leaf’ 1 carpel = 1 pistil 1 carpel = 1 pistil
This gynoecium is
monocarpic
The pistil (vase-shaped structure) is made up of ONE carpel (one carpel)
The Flower The Flower
When pistil = carpel When pistil = carpel
1. Monocarpic – when flower has only 1 pistil 2. Apocarpic – when flower has 2+ pistils
• e.g., 6 leaves (carpels)
separately form pistils
• then the flower has 6
legume carpels and 6 pistils,
flower
legume 1 carpel = 1 pistil
fruit This gynoecium is
monocarpic
(one carpel) 6 fruits (pistils) from 1 flower
Gynoecium is apocarpic with 6 carpels and 6 pistils
Caltha palustris - Marsh marigold
16The Flower The Flower
When pistil =/ carpel
3 floral ‘leaves’ in 3 carpels = 1 pistil 3 carpels = 1 pistil
gynoecium fuse 3 styles 1 style tomato – 2 carpels passion fruit– 3 carpels starfruit – 5 carpels
3. Syncarpic – when This gynoecium is This gynoecium is
3. Syncarpic – when
flower has only 1 pistil flower has only 1 pistil • number of fused carpels is often
syncarpic syncarpic
but 2+ carpels but 2+ carpels clear in a cross section of the fruit
The Flower The Flower
Placentation types - arrangement of ovules, Placentation types - arrangement of ovules,
provides hints to the number of carpels provides hints to the number of carpels
Marginal - found in
almost all monocarpic or
apocarpic pistils
tomato – 2 carpels passion fruit– 3 carpels starfruit – 5 carpels Axile - found in some
syncarpic pistils
= placenta tissue • number of fused carpels is often
clear in a cross section of the fruit
17The Flower The Flower
Placentation types - arrangement of ovules, Placentation types - arrangement of ovules,
provides hints to the number of carpels provides hints to the number of carpels
Parietal - found in Free-central - found in
some syncarpic a few syncarpic pistils
pistils
The Flower The Flower
Placentation types - arrangement of ovules, Numerical plan - merosity, arrangement of perianth
provides hints to the number of carpels • not necessarily stamens or carpels
Basal - found in
some monocarpic,
apocarpic, or
syncarpic pistils
perianth spiralled perianth 5-merous
Common in primitive Common in eudicots
angiosperms
18The Flower The Flower
Numerical plan - merosity, arrangement of perianth Symmetry plan - perianth arrangement important in
• not necessarily stamens or carpels pollination biology
perianth 4-merous perianth 3-merous Flowers radially Flowers bilaterally
symmetrical symmetrical
Occasional in eudicots Common in monocots & some
primitive angiosperms Flowers actinomorphic Flowers zygomorphic
The Flower The Flower
Connation: fusion of floral Adnation: fusion of floral
parts from the same whorl parts from different whorls
• Simple adnation
Stamens fused onto inner
Fusion of carpels Syncarpic pistil
asterids! surface of fused (connation)
petals
legumes!
• Complex adnation
Sepals, petals, and stamens fuse
to form a hypanthium
Fusion of stamens Staminal tube Fusion of petals Corolla tube
19The Flower The Flower
Adnation: fusion of floral Adnation: fusion of floral
e.g., Drimys & sandwort parts from different whorls e.g., cherry & rose parts from different whorls
No adnation!
Connation (fusion of similar
parts) may or may not occur Adnation of calyx,
corolla, & stamens
= hypanthium
The Flower The Flower
Adnation: fusion of floral Adnation: fusion of floral
e.g., feverwort, honeysuckle, apple parts from different whorls e.g., feverwort, honeysuckle, apple parts from different whorls
20The Flower The Flower
Floral formula - shorthand notation
Adnation: fusion of floral
e.g., feverwort, honeysuckle, apple parts from different whorls
CA 4 CO 4 A 8 G 4
calyx, corolla, stamens
4 sepals (CAlyx)
4 petals (COrolla)
ovary 8 stamens (Androecium)
4 carpels (Gynoecium)
hypanthium
pedicel
Oenothera biennis
Evening primrose
Onagraceae
The Flower The Flower
Floral formula - shorthand notation Floral formula - shorthand notation
—
CA 4 CO 4 A 8 G 4 CA 4 CO 4 A 8 G 4
4 sepals (CAlyx) 4 sepals (CAlyx)
4 petals (COrolla) 4 petals (COrolla)
8 stamens (Androecium) 8 stamens (Androecium)
4 carpels (Gynoecium) 4 carpels (Gynoecium)
• Carpels fused = 1 pistil Carpels fused = 1 pistil
• Ovary inferior
Oenothera biennis Oenothera biennis
Evening primrose Evening primrose
Onagraceae Onagraceae
21The Flower
Floral formula - shorthand notation
The “flower” — what is it?
• a flower is a specialized shoot that:
—
CA 4 CO 4 A 8 G 4
1. is determinate (vs. indeterminate)
4 sepals (CAlyx)
4 petals (COrolla)
8 stamens (Androecium) 2. has a modified stem with compressed internodes
4 carpels (Gynoecium)
Carpels fused = 1 pistil 3. possesses modified leaves with various functions,
Ovary inferior these determined by gene arrays (e.g., ABC model)
• Hypanthium (+ hypanthium tube)
4. often clustered in an inflorescence (larger branch)
Oenothera biennis
Evening primrose
Onagraceae
22You can also read
