Pollination Systems and Reproductive Biology


Pollination is the transfer of pollen grains from an anther to a stigma

It is required for sexual reproduction but not for asexual reproduction

Flowers are the focal point for delivery and receipt of pollen


Self-pollination vs. Outcrossing

Self-pollination is when pollen from a plant is transferred to a stigma of the same plant, either within a flower or between flowers.

Outcrossing is when pollen from one plant is transferred to the stigma of another


Pollination Syndromes are lists of features that are associated with a particular mode of pollination


Self Pollination Syndrome

Small, inconspicuous flowers

Usually unpigmented (green or white flowers)

Low pollen: ovule ratio

Anthers positioned close to stigmas


Small pollen grains


Abiotic Pollination

Wind pollination

Water Pollination

Wind Pollination


Wind Pollination Syndrome

Be small and inconspicuous

Have large amounts of tiny pollen grains

Have large feathery stigmas


Water Pollination Syndrome

Water pollinated flowers tend to:

Be small and inconspicuous (and submerged or floating)

Have lots of small pollen grains (sometimes floating)

Have large feathery stigmas (sometimes floating)


Biotic Pollination
All forms of animal pollinators















Rewards vs Attractants

REWARDS: Rewards are the things that animal pollinators visit flowers for.






Fat bodies

ATTRACTANTS: Attractants are the cues that animals use to locate flowers.






Bee Pollination

Bee-pollinated flowers tend to fall into two classes:

Showy, open, bowl-shaped flowers that are relatively unspecialized

Showy, complicated, zygomorphic flowers that are more specialized

All be flowers tend to be yellow or blue, often with UV nectar guides and scented


Butterfly Pollination

Butterfly-pollinated flowers tend to:

be large and showy

be pink or lavender

have long narrow corolla tubes

be scented


Moth Pollination

Moth-pollinated flowers tend to:

be large and showy

be white

have tubular corollas

have a sweet scent produced in the evening


Fly Pollination

Fly-pollinated flowers tend to:

have a strong unpleasant odor

be brown or orange in color


Bird Pollination

Bird-pollinated flowers tend to be:

large and showy



produce a lot of nectar

they usually lack a scent


Bat Pollination

Bat -pollinated flowers tend to:

be large and showy

be firm

be white or light-colored

have a strong scent of cabbage or fermented fruit

open at night



A pollination system, usually found in orchids, where a flower resembles a female wasp, and the male wasp lands on the flower to try to copulate, fails, and makes the same mistake again.


Obligate mutualisms

Yucca/yucca moths

Fig/fig wasps


Reproductive Biology

The study of plant reproductive methods such as phenology, breeding systems, pollination, floral structure, and dispersal.



The inability of a bisexual plant (hermaphrodite) to produce zygotes from its own pollen.

Two types:

Gametophytic--mating opportunities determined by the genotype of the pollen

Sporophytic--mating opportunities determined by the genotype of the sporophytes (pollen and egg parents).



The timing of events, particularly in reference to reproductive events.

Any scale from hourly, daily, or annual.


Breeding Systems

Systems of sexuality in flowering plants which impact the relative rates of inbreeding or outcrossing.



The simplest and most common breeding system is hermaphroditism, where each plant has both female and male functions and all flowers are perfect.



Dioecy is the second most common breeding system found in plants; individuals are either female or male and have either staminate or pistillate flowers.



Monoecy is the another common breeding system found in plants; individuals are hermaphroditic but lack perfect flowers, instead having both staminate or pistillate flowers.



The breeding system in which there are two types of plants, females (with pistillate flowers) and hermaphrodites (with perfect flowers).



The breeding system in which there is a single type of plant, but with two types of flowers, pistillate and hermaphroditic.



The breeding system in which there are two types of plants, males (with staminate flowers) and hermaphrodites (with perfect flowers).



The breeding system in which there is a single type of plant, but with two types of flowers, staminate and hermaphroditic.


Evolution of Breeding Systems

Hermaphroditism and dioecy are stable systems, the other breeding systems are sometimes thought to be transitory between them.

Generally breeding system evolution is thought to be triggered by inbreeding and inbreeding depression, but resource allocation may also play a role.



Movement of plants from place to place, usually in the form of seeds, but sometimes also in the form of pollen.


Dispersal is the mechanism through which gene flow occurs.

Dispersal Vectors

Abiotic elements: wind, water, gravity.


Biotic elements: animals (by eating, sticking to surface, pollination) or by self dispersal (explosive fruits).