the flower - what is it?. the flower what is it? from schleiden 1855 foliar theory of flower - j.w....

The Flower - The Flower -

What is it?What is it?

The Flower — What is it?The Flower — What is it?

from Schleiden 1855from Schleiden 1855

• “ “foliar theoryfoliar theory” of flower - J.W. ” of flower - J.W. von Goethe in “von Goethe in “Attempt to Interpret Attempt to Interpret the Metamorphosis of Plantsthe Metamorphosis of Plants” ” (1790)(1790)

• thus, a flower is a specialized shoot that:thus, a flower is a specialized shoot that:

1.1. is is determinatedeterminate (vs. indeterminate) (vs. indeterminate)

2.2. has a has a modified stemmodified stem with compressed internodes with compressed internodes

3.3. possesses possesses modified leavesmodified leaves with various functions, with various functions, these determined by gene arrays (e.g., ABC model)these determined by gene arrays (e.g., ABC model)

4.4. often clustered in an often clustered in an inflorescenceinflorescence (larger branch) (larger branch)

The Flower — What is it?The Flower — What is it?

The FlowerThe Flower

1. 1. PedunclePeduncle: floral stalk, the stem : floral stalk, the stem supporting the flower; sometimes supporting the flower; sometimes referred to as the referred to as the pedicelpedicel

read chpt 9 in read chpt 9 in Plant Plant SystematicsSystematics!!

2. 2. ReceptacleReceptacle: modified floral : modified floral stem or axis from which arise stem or axis from which arise the floral appendages or the floral appendages or modified leavesmodified leaves


3. 3. SepalSepal: the outer whorl of : the outer whorl of leaves, green and protection; leaves, green and protection; collectively called the collectively called the calyxcalyx


4. 4. PetalPetal: the second whorl of : the second whorl of leaves, typically brightly leaves, typically brightly colored, attracting pollinators; colored, attracting pollinators; collectively called the collectively called the corollacorolla


5. 5. PerianthPerianth: collective term for : collective term for sepals and petalssepals and petals

TepalsTepals if both similarif both similar


8. 8. StamenStamen: the male structure : the male structure of flower comprising filament of flower comprising filament and antherand anther

• collectively, stamens are the collectively, stamens are the androeciumandroecium (= ‘house of (= ‘house of males’)males’)

• can be leaf-like in primitive can be leaf-like in primitive angiospermsangiosperms


6. 6. FilamentFilament: slender stalk of : slender stalk of the stamen supporting the the stamen supporting the anther; permits exsertion of anther; permits exsertion of pollen out of flowerpollen out of flower


7. 7. AntherAnther: fertile portion of : fertile portion of stamen that dehisces to release stamen that dehisces to release pollen grainspollen grains; composed of ; composed of anther sacsanther sacs


NectariesNectaries often near base of often near base of stamensstamens

• produce produce nectar rewardnectar reward for for visitors who will move pollen visitors who will move pollen (‘pollinators’)(‘pollinators’)

e.g., grass-of-parnassus & e.g., grass-of-parnassus & fritillaryfritillary


13.13. PistilPistil: flask-shaped, female : flask-shaped, female structure comprising three structure comprising three main partsmain parts

• often referred to as often referred to as carpelcarpel(s)(s)

• all pistils (1 or more) are all pistils (1 or more) are referred to as the referred to as the gynoeciumgynoecium (= ‘house of females’)(= ‘house of females’)


9. 9. OvaryOvary: basal portion of pistil : basal portion of pistil that contains ovules; at maturity that contains ovules; at maturity becomes becomes fruitfruit with seeds with seeds

10. 10. OvulesOvules: fertile portions of : fertile portions of pistil that contain a female pistil that contain a female gametophyte (embryo sac); gametophyte (embryo sac); develop into develop into seedsseeds after after fertilizationfertilization


11. 11. StyleStyle: slender stalk of pistil : slender stalk of pistil above ovary that the pollen above ovary that the pollen tubes must pass through to tubes must pass through to reach eggs in ovulesreach eggs in ovules

12. 12. StigmaStigma: receptive portion : receptive portion at top of style that receives at top of style that receives and recognizes pollenand recognizes pollen


Pollination biologyPollination biology Study of the pollen, its transfer, and movement Study of the pollen, its transfer, and movement down the styledown the style


PistilPistil vs. vs. carpelcarpel

How do you know?How do you know?

3 examples3 examples

Carpels not fusedCarpels not fused 1. 1. MonocarpicMonocarpic 2. 2. ApocarpicApocarpicCarpels fusedCarpels fused 3. 3. SyncarpicSyncarpic


1 floral ‘leaf’ in gynoecium1 floral ‘leaf’ in gynoecium

This gynoecium is This gynoecium is monocarpicmonocarpic(one carpel)(one carpel)

Folded ‘leaf’Folded ‘leaf’ 1 carpel = 1 pistil1 carpel = 1 pistil

MonocarpicMonocarpicThe FlowerThe Flower

This gynoecium is This gynoecium is monocarpicmonocarpic(one carpel)(one carpel)

1 carpel = 1 pistil1 carpel = 1 pistil


legumeslegumes

• If 9 ‘leaves’ in one flower If 9 ‘leaves’ in one flower each each separatelyseparately forms forms carpels, carpels,

• then the flower has 9 then the flower has 9 carpels and 9 pistils, carpels and 9 pistils,

• gynoecium is gynoecium is apocarpicapocarpic (separate carpels)(separate carpels)

Caltha palustris - Caltha palustris - Marsh marigoldMarsh marigold

9 fruits (pistils) from 1 flower9 fruits (pistils) from 1 flowerGynoecium is Gynoecium is apocarpicapocarpic with 9 carpels or 9 pistils with 9 carpels or 9 pistils

ApocarpicApocarpicThe FlowerThe Flower

3 floral ‘leaves’ in 3 floral ‘leaves’ in gynoecium gynoecium fusefuse

This gynoecium is This gynoecium is syncarpicsyncarpic

This gynoecium is This gynoecium is syncarpicsyncarpic

SyncarpicSyncarpicThe FlowerThe Flower

3 carpels = 1 pistil3 carpels = 1 pistil3 styles3 styles

3 carpels = 1 pistil3 carpels = 1 pistil1 style1 style

Placentation typesPlacentation types - arrangement of ovules, - arrangement of ovules, provides hints to the number of carpelsprovides hints to the number of carpels

MarginalMarginal - found in all - found in all monocarpic or apocarpic monocarpic or apocarpic pistilspistils

AxileAxile - found in some - found in some syncarpic pistilssyncarpic pistils


ParietalParietal - found in - found in some syncarpic some syncarpic pistilspistils






Free-centralFree-central - found in - found in a few syncarpic pistilsa few syncarpic pistils




Free-centralFree-central - found in - found in a few syncarpic pistilsa few syncarpic pistils

BasalBasal - found in - found in some monocarpic, some monocarpic, apocarpic, or apocarpic, or syncarpic pistilssyncarpic pistils

Flowers Flowers radiallyradially symmetricalsymmetrical

Flowers Flowers actinomorphicactinomorphic

Flowers Flowers bilaterallybilaterally symmetricalsymmetrical

Flowers Flowers zygomorphiczygomorphic

Symmetry planSymmetry plan - perianth arrangement important in - perianth arrangement important in pollination biologypollination biology


ConnationConnation: fusion of floral : fusion of floral parts from the same whorlparts from the same whorl

Fusion of carpelsFusion of carpels Syncarpic pistilSyncarpic pistil

Fusion of stamensFusion of stamens Staminal tubeStaminal tube Fusion of petalsFusion of petals Corolla tubeCorolla tube


AdnationAdnation: fusion of floral : fusion of floral parts from different whorlsparts from different whorls

No adnation!No adnation!

Connation (fusion of similar Connation (fusion of similar parts) may or may not occurparts) may or may not occur


Adnation of calyx, corolla, & stamens = hypanthium



Inflorescences - Floral DisplaysInflorescences - Floral DisplaysThe vast majority of flowering plants The vast majority of flowering plants possess flowers in clusters called an possess flowers in clusters called an inflorescenceinflorescence. .

These clusters facilitate pollination via These clusters facilitate pollination via a prominent visual display and more a prominent visual display and more efficient pollen uptake and deposition.efficient pollen uptake and deposition.

A shift from widely A shift from widely spaced single flowers to spaced single flowers to an inflorescence required an inflorescence required condensation of shoots condensation of shoots and the loss of the and the loss of the intervening leaves.intervening leaves.

((PrunusPrunus or cherry) or cherry)

The simplest The simplest inflorescence type inflorescence type would thus be would thus be indeterminateindeterminate with the with the oldest flowers at the oldest flowers at the base and the younger base and the younger flowers progressively flowers progressively closer to the apical closer to the apical meristem of the shoot.meristem of the shoot.

= a = a racemeracemeRacemeRaceme

RacemeRaceme

One modification of the basic raceme is to make it compoundOne modification of the basic raceme is to make it compound

compoundcompound

PaniclePanicle

The The paniclepanicle is essentially is essentially a series of attached a series of attached racemes with the oldest racemes with the oldest racemes at the base and racemes at the base and the youngest at the apex the youngest at the apex of the inflorescence. of the inflorescence.

((ZigadenusZigadenus or white camass) or white camass)Panicle

RacemeRaceme

A second modification of the basic raceme is to lose its pedicels

Pedicel lossPedicel loss

SpikeSpike

The spike is usually associated with congested reduced flowers and often, but not always, with wind pollination.

((PlantagoPlantago or plantain) or plantain)SpikeSpike

wind pollinatedwind pollinated

The spike is usually associated with congested reduced flowers and often, but not always, with wind pollination.

SpikeSpike

animal pollinatedanimal pollinated

((CombretumCombretum - Brent’s plants) - Brent’s plants)

Besides these indeterminate inflorescences based on the Besides these indeterminate inflorescences based on the raceme, there is a series of inflorescence types based on raceme, there is a series of inflorescence types based on determinatedeterminate shoots (shoot can not grow up indefinitely). shoots (shoot can not grow up indefinitely). The simplest is the The simplest is the dichasiumdichasium..

RacemeRaceme DichasiumDichasium

The The dichasiumdichasium inflorescence is inflorescence is terminated (i.e., determinate) by the terminated (i.e., determinate) by the oldest flower and flanked by two lateral oldest flower and flanked by two lateral younger flowers. younger flowers.

DichasiumDichasium

((ClematisClematis or virgin’s-bower) or virgin’s-bower)

oldest floweroldest flower

younger flowersyounger flowers

the flower - what is it?. the flower what is it? from schleiden 1855 foliar theory of flower - j.w....

Documents

flower slide

flower gynoecium

flower legumes

style slide

foliar theory of flower

male structure of flower

apocarpic carpels

syncarpic syncarpic