Transcript Pollination Biology

Let’s Do It
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When the little bluebird
Who has never said a word
Starts to sing Spring.
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It is nature that is all
Simply telling us to fall in
love
When the little bluebell
At the bottom of the dell
Starts to ring Ding dong
Ding dong.
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And that’s why birds do it,
bees do it,
Even educated fleas do it.
Let’s do it, let’s fall in love...
When the little blue clerk
In the middle of his work
Starts a tune to the moon up
above.
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-Cole Porter-
Pollination Biology
Help me!
I am rooted and I cannot move!
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Plants are stationary (usually) and thus depend on
external forces to bring their gametes together.
As a result, plant sex is extraordinarily varied and
competitive.
Some plants species may be specialized for one
pollinator.
Some plants may be served by a wide range of
pollinators. Such plant species are called
generalists.
Me thinks that a generalist might be a wise thing to
be! What thinks you?
Pollination as a science…
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The study of pollination brings together many
disciplines, such as botany, horticulture,
entomology, zoology, and ecology. The
pollination process as an interaction between
flower and vector was first addressed in the
18th century by Christian Konrad Sprengel in
his work Das entdeckte Geheimnis der Natur
im Bau und in der Befruchtung der Blumen
(Berlin 1793).
Christian Konrad Sprengel
(1750-1816)
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One of the founders of pollination ecology as a scientific
discipline. Together with one of his predecessors, Josef G.
Köhlreuter, he is still the classic author in this field.
During his lifetime, his work was neglected, not only because it
seemed to many of his contemporaries as obscene that flowers
had something to do with sexual functions, but also because
the immanent importance of his findings on the aspects of
selection and evolution was not recognized.
Until C. Darwin’s book On the various contrivances by which
British and foreign orchids are fertilised by insects, and on the
good effects of intercrossing. (London 1862), floral ecology was
not considered a 'proper science'.
Plant Pollination
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The greatest percentage of all plant
pollination is biotic in nature (animal
assisted).
Only 10% (some say 20%) of flowering
plants are pollinated without animal
assistance (sometimes called abiotic
pollination).
Abiotic Pollination
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The most common form, anemophily, is
pollination by wind. This form of pollination is
predominant in grasses, most conifers, and
many deciduous trees.
Hydrophily is pollination by water and
occurs in aquatic plants which release their
pollen directly into the surrounding water.
We already know or will know…
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Sperm of seed plants are packaged in pollen grains
for transport to ovules or stigmas (aka pollination).
Conifer pollination occurs largely by wind.
Most flowering plants are pollinated by animals
(insects included here).
Wind pollination predominates in the grasses and
other ecologically dominant families.
Water pollination is rare.
Those observant Babylonians
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1500 BC is when Babylonians first noted that
the yellow pollen of date palms must be
applied to the flowers of fruit-bearing trees in
order for the trees to produce fruit.
So Babylonian date farmers started
spreading the yellow pollen on date flowers
by hand to increase fruit production.
Today, somewhere in the world…
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I wonder if this man is
thinking…”I need to
thank a Babylonian for
this exciting job”?
No Pollination No People
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Pollination remains essential to human
welfare today.
Most human food comes from cereal grains
(Poaceae) and legumes (Fabaceae) all of
which result from pollination.
Nearly all edible fruits would not exist without
pollination.
Those Voluptuous Flowers
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Be us prurient or puritanical, we all know that
bright blooms are just inviting, irresistible
advertisements for ‘falling in love’.
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Flowers are adaptations for pollination. How
they ‘get’ it is how they bloom.
Whilst in Madagascar,
Darwin speculated…
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There had to be a some type of animal
pollinator with a VERY long tongue because
there was an orchid species there whose
flowers had a 30 cm long spur to reach the
flower nectary. He predicted there was a
moth with a tongue long enough.
Floral Pollination Syndromes
(syn FPS)
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The link between floral color, scent, time of
flowering, structure, and rewards on the
plant’s side and animal pollinator sensory
capacity, behavior, and diet on the other is
the basis for FPS.
The link may be strong enough that a plant
and a pollinator adapt to each other, to
coevolve so to speak.
Yucca and FPS
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The yuccas comprise the genus Yucca of
40-50 species of perennials, shrubs, and
trees in the agave family Agavaceae,
notable for their rosettes of evergreen, tough,
sword-shaped leaves and large terminal
clusters of white or whitish flowers. They are
native to the hot and dry (arid) parts of North
America, Central America, and the West
Indies.
Yucca and FPS continued…
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Yucca pollination seldom occurs without the aid of
females of several species of yucca moths,
especially Pronuba yuccasella and Prodoxus
quinquepunctellus.
These moths purposefully transfer the pollen from
the stamens of one plant to the stigma of another,
and at the same time lay eggs in the flower; the moth
larva then feeds on some of the developing seeds,
but far from all.
Yucca and FPS continued yet again…
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The relationship between yucca plants and
yucca moths is one of the classic examples
of an obligate pollination/seed predation
mutualism.
And again… (Yucca and FPS)
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The moth makes sure not to lay too many
eggs in each flower to prevent the larva from
eating all of the yucca seeds.
Pollination of soapweed yucca is dependent
upon the yucca moth (Pronuba yuccasella)
or other pollinating insects such as small flies
(Pseudocalliope spp.)
Yucca FPS Research Results…
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In a study to determine the relationship between
soapweed yucca and the yucca moth, 124 plants
with a mean of 291 ovules per plant had 138 viable
seeds after consumption by (adult?) and larval yucca
moths. The maximum number of larvae per fruit was
19. In Colorado, the number of surviving seeds
increased with elevation despite fewer fruits. This
was likely due to decreased predation by the yucca
moth, which prefers the warmer temperatures of the
Great Plains over those experienced at higher
elevations
Yucca glauca Nutt.
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Great Plains yucca,
Spanish bayonet,
needle and thread,
beargrass,
small soapweed,
soapweed yucca,
yucca.
Montana native
Look for one in your
neighborhood.
Wind Pollination
(aka anemophily)
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Wind pollinated flowering plants are
characterized by the production of large
amounts of pollen that is readily transported
by the wind (small and light).
In many wind-pollinated angiosperms, each
flower has only a few ovules, and often only
one of them produces a seed.
Wind pollination is unusual in the tropics,
especially in lowland rain forests.
Wind Pollination
(aka anemophily)
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Temperate forests, in contrast, are dominated by
wind-pollinated trees such as oaks, beeches,
hickories, walnuts, birches, and many conifers in our
Northern Hemisphere.
Pollen shed in wind-pollinated temperate species
occurs at the beginning of the growing season,
before or as leaves develop as a leafless forest has
fewer obstacles to interrupt pollen flow.
Wind Pollination
(aka anemophily)
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Pollen shed is also timed to avoid high
humidity (moisture weighs pollen down and
reduces its buoyancy).
Pollen shed is also timed to avoid periods of
seasonal rain (which carries pollen down out
of the air currents.)
Wind Pollination
(aka anemophily)
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Corn (Family Poaceae) illustrates another
common feature of wind-pollination:
unisexual flowers.
Corn pollen in borne is staminate flowers in
the tassel at the top of the plant and the
‘female’ stigmas are the “silk” that emerge
from the top of what will become the ear of
corn.
Anemophily, You, and Ah-Chew!
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For those of you (not me fortunately!) that
suffer from ‘hay fever’, your symptoms of
watering eyes to sneezing might be caused
from an allergic reaction to proteins in the
outer pollen wall of some wind-pollinated
species such as ragweed (Ambrosia spp.),
Carolus L.’s ‘food of the gods!’
'Safe Sex in the Garden'
Sticking to Female Plants May Help Reduce Allergies, Book Says
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More than 35 million Americans suffer from
seasonal allergies, according to the
American Academy of Allergy, Asthma and
Immunology. Part of the problem, says
horticulturist Thomas Leo Ogren, is rooted in
the types of plants commonly used in
landscaping.
'Safe Sex in the Garden'
Sticking to Female Plants May Help Reduce Allergies, Book Says
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For about 50 years, commercial and residential
landscapers have been planting single-sex male
trees and shrubs almost exclusively. Males don't
litter the ground with seeds, fruits or pods but they
do emit high quantities of pollen into the air and up
our noses.
Cities like Billings forbid the intentional planting of
cottonwood trees unless they are ‘cottonless’ (aka
male…)
'Safe Sex in the Garden'
Sticking to Female Plants May Help Reduce Allergies, Book Says
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The solution, Ogren suggest, may lie in a
form of gardening girl power. In his book,
Safe Sex in the Garden, Ogren argues that
boosting the use of female plants, which
absorb pollen in the air, could help
dramatically reduce the suffering of those
affected by pollen allergies.
Believe it or not.
Water Pollination
(aka hydrophily)
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Water pollination is limited to about 150
angiosperm species in 31 genera and 11
families.
Almost half of these species are marine or
grow in brackish water.
Nine of the eleven families are monocots.
Water Pollination
(aka hydrophily)
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Pollen may be transported above, on, or
below the water surface.
Plants that pollinate under water often have
filamentous, or eel-shaped pollen borne in
mucilaginous strands.
Animal Pollination
(aka biotic pollination)
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Thought to be an important factor in the
evolutionary success of angiosperms.
Animals are often more efficient transporters
of pollen than wind, and they can be found
where there is little wind (dense tropical
forests).
Animals promote cross-pollination (thus plant
vigor) by moving between plants.
Animal Pollination
(aka biotic pollination)
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Animal pollination has driven diversification
in many plant groups.
Evolution associated with animal pollination
is nowhere more evident than in the
Orchidaceae. Many species in the large
family are separated by floral structure
reproductive isolation (whilst in Madagascar,
Darwin speculated…)
This may or may not be such a good thing…
Animals and FPS
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Flowers attract their pollinators with color:
Bees – blue, yellow, purple.
Butterflies – bright, often red.
Moths – white or pale colors (see them at
night)
Birds – bright, often red
Bats – white (see them at night)
Animals and FPS
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Flowers open and emit scents when their pollinators
are active:
Bees – fresh, strong scented flowers open during the
day.
Moths – sweet, strong smelling flowers opening at
dusk and throughout the night.
Bats – musky, strong flowers opening at night.
Birds – are not attracted by scent but by color and
thus utilize flowers during the day.
Animals and FPS
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About 60 species of non-flying mammals
have been documented as pollinators of
about 100 plant species.
Flowers pollinated by non-flying mammals
have a broad range of floral characteristics
due to differences in morphology and
foraging behavior of the three groups of
pollinating mammals.
Animals and FPS
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Primates – flowers pollinated by primates
tend to be unscented and very large to
accommodate the large size of the animals.
Marsupials – flowers pollinated by
marsupials are usually located in the forest
canopy.
Rodents – flowers pollinated by rodents tend
to be close to the ground and have a yeasty
odor.
Animals and FPS
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Flowers are built to fit their pollinators
physically and to provide them with an
appropriate reward.
In some cases, pollinators are not rewarded,
but rather are deceived into pollinating a
flower.
Deception in the plant world…
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Of the 19,500 species of orchids, about
8,000 offer no food reward to their
pollinators.
Instead they deceive or provide them with
nonnutritive rewards such as fragrant
chemicals
Drug pusher/addict relationship perhaps?
Sounds kind of like co-dependency to me!
Oh, those fraudulent orchids…
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Some orchids mimic female insects, luring males
with odors of potential mates ready for loving.
Some orchids have textures stimulating male insects
into ‘pseudo-copulation’. The insects may be duped,
but the orchid gets what it wants!
Some orchids flutter their flowers in the breeze
making them look like male bees. This provokes
other male bees in the neighborhood to attack one
impersonating flower after another, thus pollinating
them. Exploiting machismo perhaps???
We know rotting flesh attracts flies…
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So, if I am a flower that emits the scent of
rotting meat, I can deceive a fly into
investigating my interior and pollinating me.
I smell good…
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“I just love the way the fragrant chemicals
(pheremones?) in those New World orchids
make my hind tibiae smell. All the girl
euglossines really come a flying when I wear
that cologne, and the orchids really seem to
appreciate me too!!!”
-Calvin Klein aka male euglossine bee-
Self-Pollination
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Some plants are self-fertile or and can
pollinate themselves.
Self-pollination (autogamy): pollen moves to
the female part of the same flower, or to
another flower on the same individual plant.
Avoiding Self-pollination
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It has long been known that many plants
avoid self-pollination and thus the possible
harmful consequences of inbreeding.
Avoiding self-pollination my be achieved by
separating male and female gametes in
space or in time.
Can you think of examples of this???
Cross-pollination
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Some plants have chemical or physical
barriers to self-pollination and need to be
cross-pollinated.
Cross-pollination (syngamy): pollen is
delivered to a flower of a different plant.
Plants adapted to cross-pollination often
have taller stamens than carpels to better
spread pollen to other flowers.
Examples from the continuum…
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Peaches are considered self-fertile because a
commercial crop can be produced without crosspollination, though cross-pollination usually gives a
better crop.
Apples are considered self-incompatible, because a
commercial crop must be cross-pollinated. If all of
the trees in the orchard are clones (ie Red Delicious)
you need to introduce pollen from another variety of
apple or you won’t get any Red Delicious to sell.
To Bee or Not to Bee
Pollination Management
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A branch of agriculture that seeks to protect
and enhance present pollinators and often
involves the culture and addition of
pollinators in monoculture situations, such as
commercial fruit orchards.
The largest managed pollination event in the
world is in California almond orchards, where
nearly half of the US honey bees are trucked
to the almond orchards each spring.
Pollination Management
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The ecological and financial importance of
natural pollination by insects to agricultural
crops, improving their quality and quantity, is
becoming more and more appreciated and
has given rise to new financial opportunities.
Pollination Management
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Agricultural monocultures require great
concentrations of pollinators at bloom time yet deem
vast areas forage poor for the rest of the season.
Pollinator populations are declining due to pesticide
misuse, new diseases and parasites of bees, decline
of beekeeping, suburban development, habitat
destruction, and public paranoia about bees.
Widespread aerial spraying for mosquitoes due to
West Nile fears is causing an acceleration of the loss
of pollinators.
Pollination Management
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The vicinity of a forest or wild grasslands with
native pollinators near agricultural crops can
improve their yield by about 20%. The
benefits of native pollinators may result in
forest owners demanding payment for their
contribution in the improved crop results - a
simple example of the economic value of
ecological services.
Farewell to the Plant Family
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Discovering that plants advertise and compete like
humans makes them more understandable, and
creates a further bond between us. Consider not
only the plants and flowers, but also their partners
and environment as a dynamic and intimately
interactive system. Evolving through deluge and
drought, and flowering with or without pollination,
plants are sublimely optimistic.
-Angela Overy- Sex in Your Garden (Fulcrum, 1997)
Final Assignment
Biology 315/325 class of 2008
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Explain pollination through the use of interpretive dance!
Be creative! Have fun! Dance like there is no tomorrow!
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Due date? You tell me!!! Thanks for being you!!!