Pollination Flashcards
What are the male and female gametes produced in flowering plants?
Male gametes are produced in the pollen grain and female gametes in the embryo sac.
What is pollination?
Pollination is the transfer of pollen grains from the anther to the stigma of the pistil.
What adaptations have flowering plants evolved for pollination?
Flowering plants have evolved an amazing array of adaptations to achieve pollination.
What are the three types of pollination based on the source of pollen?
- Autogamy
- Geitonogamy
- Xenogamy/allogamy/cross pollination
Define autogamy in the context of pollination.
Autogamy is the process of transfer of pollen grains from the anther to the stigma of the same flower.
Provide an example of a plant that undergoes autogamy.
Pea.
What is a chasmogamous flower?
A chasmogamous flower is a normal flower that opens and exposes the anthers and stigma.
What is a cleistogamous flower?
A cleistogamous flower is one that does not open and remains closed, facilitating self-pollination.
Is complete autogamy common in flowering plants?
Complete autogamy is rather rare.
What conditions are required for autogamy to occur?
- Synchrony in pollen release and stigma receptivity
- Proximity of anther and stigma
Fill in the blank: The process of transfer of pollen grains from the anther to the stigma of the same flower is called _______.
[Autogamy]
What are chasmogamous flowers?
Flowers that open to allow pollination.
What are cleistogamous flowers?
Flowers which do not open at all.
What is a characteristic of cleistogamous flowers?
The anther and stigma lie close to each other.
What happens when anthers dehisce in cleistogamous flowers?
Pollen grains come in contact with the stigma and pollination takes place.
True or False: Cleistogamous flowers are invariably autogamous.
True.
What is autogamy?
Self-pollination in cleistogamous flowers.
List advantages of autogamy in cleistogamous flowers.
- Assures seed set in absence of pollinators
- No chance of cross pollen landing on the stigma
What is a disadvantage of cleistogamous flowers?
Causes inbreeding depression.
What is geitonogamy?
Transfer of pollen grains from the anther to the stigma of another flower of the same plant.
How is geitonogamy similar to autogamy?
Genetically similar since pollen comes from the same plant.
What does geitonogamy resemble functionally?
Cross pollination/xenogamy involving pollinating agents.
What is xenogamy?
Transfer of pollen grains from the anther of a flower to the stigma of another plant of the same species.
What is the significance of xenogamy?
Brings genetically different types of pollen grains to the stigma.
