Pollination, Pollinizer, and Pollinator
Pollination is a crucial process in the production of fruits and nuts, as it is required for fruit development in many plant species. Understanding the roles of pollination, pollinizer, and pollinator is essential for proper orchard management and fruit production.
What is Pollination?
Pollination refers to the transfer of pollen from the male part of a flower (the stamen) to the female part of a flower (the pistil). This transfer is necessary for fertilization to occur, which results in the formation of seeds and the development of fruit. Pollination can be achieved through various mechanisms, such as:
- Wind: For trees like many nut trees (e.g., almonds, walnuts).
- Insects: Bees (especially honeybees) are the primary pollinators for most fruit trees.
- Animals: Certain animals, including birds and bats, can also transfer pollen.
- Water: Some plants depend on water to carry pollen.
After pollen transfer, it must germinate and travel to the ovary of the flower, where fertilization takes place, with the male pollen cell merging with the female egg cell. Successful fertilization depends on environmental conditions and compatibility between the pollen and pistil.
Key Terms Related to Pollination
- Pollinizer:
The pollinizer is the source of pollen, typically referring to the cultivar or variety that provides pollen for cross-pollination. For example, in apple orchards, the Golden Delicious variety may be used as a pollinizer for Red Delicious apples.
- Pollinator:
A pollinator is the agent responsible for transferring pollen from the stamen of one flower to the pistil of another. Common pollinators include bees, butterflies, moths, wind, birds, and even humans in some cases.
Self-Pollination vs. Cross-Pollination
- Self-Pollination:
Occurs when the pollen from a flower fertilizes its own pistil or a pistil on the same tree. Self-pollinating plants can produce fruit without requiring pollen from another plant.
Example: Most peach varieties (e.g., Red Haven) can produce fruit by self-pollination.
- Cross-Pollination:
Happens when pollen from one flower fertilizes the pistil of another flower, typically from a different tree or variety of the same species.
Example: In apple orchards, the Golden Delicious variety is often used to cross-pollinate the Red Delicious variety.
Self-Fruitful vs. Cross-Fruitful
- Self-Fruitful:
A variety is self-fruitful if it can produce satisfactory fruit without needing pollen from another variety. This can occur either through self-pollination (like peaches) or through parthenocarpy (seedless fruit production).
Example: Some satsuma varieties of citrus are self-fruitful because they can set fruit without pollen from another variety.
- Cross-Fruitful:
A variety is cross-fruitful if it requires cross-pollination from another variety to produce satisfactory fruit. For example, the Red Delicious apple requires pollen from varieties like Golden Delicious for optimal fruit production.
Parthenocarpic Fruits
Parthenocarpic refers to fruits that develop without the need for fertilization, resulting in seedless fruit. These fruits do not require pollen or pollination to form fruit.
Example: Satsuma mandarins are parthenocarpic, meaning they can produce seedless fruit without pollen from another variety.
Perfect-Flowered Plants
A perfect-flowered plant has both functional male and female reproductive parts. This means that the flowers contain both stamens (male parts) and pistils (female parts), allowing the plant to potentially self-pollinate.
Example: The Carlos muscadine grape is a perfect-flowered variety, meaning it has both male and female flower parts and can serve as a pollinizer for female muscadine varieties like Fry.
Role of Pollinators and Pollinizers
- Pollinator:
The pollinator is the agent that physically transfers pollen from one flower to another. Common pollinators include:
- Bees (especially honeybees)
- Wind
- Butterflies and moths
- Birds (like hummingbirds)
- Humans (in some managed systems)
- Pollinizer:
A pollinizer is the source of pollen. It typically refers to the cultivar of a plant that provides pollen for the purpose of cross-pollination.
- Example: In apple orchards, a Golden Delicious apple tree may act as the pollinizer for Red Delicious apples.
Arranging Pollinator Varieties in Plantings
- Self-Fruitful Plants:
For self-fruitful plants (like many peach and some citrus varieties), only a single variety is needed for fruit production. They do not require another variety for cross-pollination. - Cross-Pollination Requirements:
For plants requiring cross-pollination, growers should plant two or more varieties to ensure sufficient pollen transfer.
- Example: In apple orchards, it’s common to plant Red Delicious and Golden Delicious varieties together to ensure cross-pollination.
- For optimal pollination, pollinizer trees can be planted as every third tree in every third row of an orchard.
