Pollination is the process of transfer of pollen grains from the anther of a stamen to the stigma of a carpel of a flower.
Pollination
- Self-pollination
- Cross-pollination
Self-pollination
The transfer of pollen grains from the anther of a flower to the stigma of the same flower or another flower on the same plant is called self-pollination. Examples: Wheat, tobacco, pea etc.
Types
Autogamy: Transfer on the same flower.
Geitonogamy: Transfer on different flowers of the same plant.
Xenogamy: Transfer between same kind of flowers on different plants.
Favouring Conditions:
- Bisexuality, monoecious
- Homogamy
- Cleistogamy
Cross-Pollination
The transfer of pollen grains from the anther of a flower on one plant to the stigma of a flower on another plant of the same species is called cross-pollination. Examples: Hibiscus, china rose, brinjal etc.
Also Read Respiration in Plants
Favouring Conditions:
- Unisexuality
- Self-sterility
- Self-poisoning
- Heterostyly
- Herkogamy
- Dichogamy
- Protandry
- Protogyny
Agents
| Agent | Method | Examples of plants |
|---|---|---|
| Insect | Entomophily | Sweet pea, Dahlia |
| Wind | Anemophily | Maize |
| Water | Hydrophily | Vallisneria |
| Bird | Ornithophily | Bignonia, canna |
| Bat | Chiropterophily | Agave, Saguaro |
| Snail | Malacophily | Volvulopsis nummularium |
| Elephant | Elephophily | Rafflesia |
| Bee | Melittophily | Apple, almond |
| Butterfly | Psychophily | Asclepias tuberosa, Echinacea purpurea |
| Moth | Phalaenophily | Liatris spicata, Camassia scillioides |
| Fly | Myophily/ Sapromyophily | Habenaria obtusata, Trichopoda sp. |
| Beetle | Cantharophily | Pond lily, Magnolia |
Differences
| Self | Cross |
|---|---|
| It is the transfer of pollen grains from the anther to the stigma of the same flower. | It is the transfer of pollen grains from the anther of one flower to the stigma of another flower of a different plant of the same species. |
| It does not require any external agent, such as wind, water or insects to carry out pollination. | It requires an external agent for pollination to occur. |
| It can take place even when the flower is closed. | It can occur only when the flower is open. |
| In self-pollinated flowers, the anther and stigma mature at the same time. | In cross-pollinated flowers, the anther and stigma mature at different times. |
| It preserves parental characters. | It does not preserve parental characters. |
| New varieties cannot be produced. | New varieties can be produced |
| As new variations are not possible, the off-springs cannot adapt to changing environmental conditions. | As new variations are possible, the offspring are healthier and are able to adapt to changing environmental conditions. |
Fertilization~ Read here
Follow us