09 - Tree to seed

what are flowers

modified leaves

Sepals

Protect inner flower organs before bud opens

Frequently green

Can be free or fused to form tube

Petals

Typically colorful to attract pollinators

Can be free or fused to form tube

Stamen

Filament + anther

pollen producing

how many pollen sacs do anthers have

4

stigma

Sticky landing platform for pollen

sometimes its key and lock

style

Connects stigma with ovary

helps pollen go down to oavry

Ovary

An ovary can have one to many ovules

An ovule only has one egg cell

Carpels versus pistils

4 free carpels = 4 pistils

3 partially fused carpels* = 1 pistil

3 fully fused carpels* = 1 pistil

One carpel, one pistil, one ovary, one ovule

example

Cherry, peach, apricot, almond, olive

feritlization of single egg cell → cherry pit

Many carpels, many pistils, 1 ovary each, 1 ovule

Blackberry, raspberry

3 carpels, 1 pistil, 3 ovaries, many ovules per ovary

Cucumber, zucchini

Generalized flower structure

1. Sepals (0-3-4-5-many)

2. Petals (0-3-4-5-many)

3. Stamen (0-many)

4. Pistils (0-many)

why is there so many ways flowers reproduce

all the variations = big diversity of reproductive sflowers

sexual organ types plants

Hermaphroditism

Monoecy

dioecy

Hermaphroditism

Complete flower

have female and male organgs on all flowers in the plamt

Monoecy

have only male or only female in each flower, but both in the plant

dioecy

plant only have male/ femlae flowers

percent of Hermaphroditism

and exmaple

75

raspberry, trillium

percent of Monoecy and exmaple

17

corn

hazel nut

percent of dioecy and exmaple

6

hemp, asparagus

Hermaphroditism - ways they reproduce

selfing within flower

selfing between flower

outcrossing

Monoecy - ways they reproduce

selfing between flower

outcrossing

dioecy - ways they reproduce

outcrossing

selfing

within same plant

outcrossing

between diff plants

who can self polinate

Adaptive under certain circumstances

hermaphrodite

which is better selfing or outcrossing

outcrossing

inbreeding can lead to inbredding depresion

how do Monoecious & hermaphroditic species avoid selfing

a. Temporal separation

b. Spatial separation

c. Self incompatibility

a. Temporal separation

Sexual phases separated in time

females open at one time and the males

example of male opening first

fireweed

example of female opneing first

blood root

b. Spatial separation

sexual organs within flowers are spaced out

Special type of spatial separation

(1) Individuals with high anthers and short styles

(2) Individuals with low anthers and long styles

c. Self incompatibility

make it so its gentcially imposible to mate

No fertilization with own pollen! Biochemical self recognition

out of all inbreeding avoidance which is the best

self incompatibility

Self incompatibility

situation in many other tree species in the Rose family

apple, pear, cherry, plum

• Temporal & spatial separations is best for

Gender specialization (mechanics) (getting pollen on insect )

what is self incompability the best for

Selfing avoidance

exam with Spatial, temporal separation AND self incompatibility!

sage

why does sage need all 3 mechanisim

T and S separations: ease of pollen pickup and delivery

→ better mechanics (less pollen waste)

Self-incompatibility: ultimate selfing avoidance!

what did invention of flowers: trigger

largest diversity of plants ever

Forces behind the evolution of flowers

Assurance of seed set

Sheer mechanics, bring female and male gametes together

Inbreeding avoidance

Create high-quality offspring, avoid selfing → avoid inbreeding depression

Pollination syndromes specilization

• Floral architecture to optimize pollen uptake and deposition

• Adaptation to pollinators’ senses for precise attraction (sight, smell, taste, touch)

• Adaptation to food requirements of pollinators (fitting reward) → Flower shape, color, odor; nature of reward

type of Pollination

abiotic and biotic

what is abiotic pollination

non directed and can not be trained

wind, water

what is biotic pollination

directed and cann be tarined

→ pollinator needs reward (pollen, nectar)

→ specialized organ construction

animals

how many plants are wing pollinated

10%

where is wind pollination most common

• Higher latitudes and altitudes

• Dry environments

• Open vegetation '

• Island floras

Habitats with fewer insects or generally more wind

examples of wind pollinated

grass

characteristics of wind pollinated

Small, inconspicuous flowers

No special colors

No nectar

Long filaments

Long (feathery branched) styles/stigmas

not as pretty

Very small fraction of pollen reaches stigma

→ cheap but not very efficient ‘

→ large quantity of pollen necessary

types of Biotic pollination

Specialists and Generalist

Specialists

rely on a more narrow group of pollinators Sometimes: exclusive relationship → one pollinator serves one plant = tight co-evolution

Generalist

flowering plants attract wide range of pollinators

example of generalist species

golden rod

charcetristics of generalist

Multiple flowers making up landing platforms for insects of different sizes to roam

Non-specialized food; pollen and nectar

have to deal with getting pollen from othre species cuz visits many other types of flowers

types of biotic specilized pollinators

bees, flies, butterflies, moths, hummingbirds

is bee polination that importnat and why

Bees: most important pollinator group

Pollinate more plant species than any other animal group

Bees originated appr. 80 MYA → diversified along with the evolutionary radiation of flowering plants

Adult bees live on nectar → nectaries, 30-35% sugar
Larvae (juveniles) live on pollen (rich in protein)

Bee pollination characteristics

Bright colors yellow, blue, UV '

→ bees do not see red

Nectar guides '

Nectar hidden → only bees can reach it (architecture) or open it (power)

Cheating flowers (bees) results

→ limits cost of reproduction

→ relies on the fact that there are more honest than cheating flowers

Cheating flowers (bees) example

→ smell, touch, form mimics female bees

→ attraction of males

→ males try to copulate

→ pollen uptake and deposition

→ coevolution!

Fly pollination

Dull, white or reddish flowers

Putrid or otherwise deceptive smell

melt away snow and pokes out atrract flies

Butterfly pollination

Sight and smell is nice and sweet

Red and orange as the most distinct colours

Long narrow flower tube → long proboscis of butterflies → no nectar robbing by non-pollinating insects

plat form for lands cuz they cant hover

Moth pollination

Moths: night-active

White or dull flowers with a very strong smell (mostly emitted after sunset)

Long and narrow floral tube

Hummingbirds pollination

Good sense of colour, attracted to red or yellow

Bad sense of smell → little flower odour

Birds lap up nectar with their tongue → more fluid nectar than for insects, and more of it

Long, tubular corolla suited to long beak, wider than for moths/butterflies

no platforms cuz can hover

What plant sexual system is described in the following statement?

Each individual flower contains both male and female organs

Hermaphroditic

1. Where are pollen produced

In the anthers

1. What plant sexual system is described in the following statement?

Each individual flower is unisexual and hence contains either male or female organs, but both sexes are present on one plant individual, ie one plant individual has more than one flower and sex

Monoecious

1. What plant sexual system is described in the following statement?

Each individual flower and individual plant is unisexual, thus this sex expression is identical to the most common form among animal

Dioecious

1. In which sexual system is selfing impossible?

Dioecy

1. Which sexual systems needs mechanisms to avoid selfing? Choose all appropriate answers

Hermaphroditism, Monoecy

What is the (legitimate) pollinator most likely after when visiting a flower which is dark red, relatively large and giving off a smell of decaying flesh?

Rotting animal protein for its offspring

1. What syndrome/mechanism is described in the following sentence? 

Tissue of a particular part of the carpel recognizes the genetic makeup of a pollen grain or a germinating pollen tube and rejects genetically similar or identical pollen tubes from fertilization

Complete self-incompatibility

If the farmer Rajit wants to grow and harvest fruits like apples, cherries or pears, how many individuals of trees per species does he need to plant at least on his farm? Note that all these tree species are hermaphroditic.

2

1. What type of pollen dispersal syndrome is described as the cheapest

wind

Your granddad comes home from a walk in the Rouge Urban National Park and tells you about a beautiful flower he discovered. It was blue and he had never before seen a flower of that color. He sat down next to it because he wanted to see who would pollinate the flower, but it was rather windy and cold, so no pollinators came while he waited. What is the most likely pollinator?

bee

1. Depending on the sexual system and number of flowers per plant individual of a particular plant species, in which of the three adaptations (temporal separation of genders, spatial separation of genders, complete self-incompatibility) can selfing accidents happen? Choose all appropriate solutions

Temporal separation of sexes

Spatial separation of sexes

1. What fits the following description?

Typically, multiple small flowers make up a two- or three-dimensional structure for pollinators of various sizes and identities to land and collect pollen and nectar

Generalist pollination 

1. What fits the following description?

Typically, a flower is constructed to suit the body size and shape of one particular pollinator (group). Also, the floral reward and advertisement are tailored toward one particular pollinator (grou

Specialist pollination

1. In sexually deceptive orchids, what is the most likely pollinator?

Male bee

In sexually deceptive orchids, through what means is a visitor made to believe that the flower is a sexual partner? Choose all appropriate answers

Through deceptive odors, 

Through deceptive surface structures, 

Through deceptive visual cues

1. What is the most likely pollinator of the inflorescence in the photo? On the left is a shot of the whole inflorescence, while on the right is a close-up of individual flowers.

Generalist pollinators

1. What costs can a flower targeting insects as pollinators mimicking rotting flesh avoid?

nectar

The flower is small and inconspicuous. There is no nectar or odor

-  Wind                    

The flower is orange, it produces nectar and a pleasant odor

- Butterfly                     

The filaments are very long and weak which leads to anthers dangling loosely

- Wind              

The flower is red, does not produce any odor but a lot of runny nectar presented at the bottom of a long corolla (floral tube) which is approximately 7 mm wide

- Hummingbird           

The flower is dark red, relatively large and if gives off a smell of decaying flesh

- fly

The flower is green and the stigma is strongly dissected or branched and extending as much as possible away from the flower

- Wind 

The flower is red, it has a small landing platform for the pollinator to rest on while visiting, and the flower tube is long and narrow

-  Butterfly          

The flower is white, it has a very small landing platform for the pollinator to rest on while visiting, and it produces nectar hidden at the bottom of a long and narrow corolla

- Hawkmoth            

The flower has a small landing platform for the pollinator to rest on while visiting, and it produces a strong and pleasant odor just in the night.

-  Hawkmoth 

The flower is blue and has dark stripes pointing towards the center of the flower

-Bee