What are the 3 types of pollination?

There are plenty of ways for plants to pollinate themselves, be it with wind or insects. Read on to find out exactly how plants are able to reproduce.

In the middle you can see the pistil of a male flower, the stamens with pollen are located on the outside [Photo: yogo/ Shutterstock.com]

Now, what was that about the birds and the bees? Long after that fateful lesson in Biology class, it’s easy to forget exactly how plants are able to reproduce. Here’s a little refresher on pollinators, animal flowering, self- and cross-pollination, and more.

What is pollination?

Pollination is the process of transferring pollen to the stigma or ovule of a plant. Here, as with human reproduction, two halves of genetic material come together: one from the male pollen, the other from the female ovary. If all goes well, pollen moves through the plant’s pollen tube to reach the pistil of the flower. After several days, it will reach the embryo sac. Here, the pollen fuses with the female ovary, and the genetic material is finally combined.

What are the different types of pollination?

When it comes to pollination fertilising the plant, there are two types: self-pollination and cross-pollination.

Self-pollination

Self-pollinators that reproduce with themselves. They combine their own ovary with their own pollen to produce seed plants. As such, a few individual plants can produce an entire colony relatively quickly. Pioneer plants are often self-pollinators. Examples of self-pollination include: snowdrops (Galanthus nivalis), barley (Hordeum vulgare), beans (Phaseolus vulgaris), and peas (Pisum sativum).

Due to a lack of pollinators, snowdrops often pollinate themselves [Photo: macrowildlife/ Shutterstock.com]

Cross-pollination

Cross-pollinators cannot fertilise themselves. In order to reproduce, the pollen and ovaries must come from different individuals of the same species. Cross-pollination encourages genetic variability, meaning the plants can adapt to changes in the environment more readily.

Cross-pollination occurs in: primroses (Primula), loosestrife (Lythrum salicaria), wood sorrel (Oxalidaceae), irises (Iris), sage (Salvia), and maize (Zea mays).

In order to reproduce, primroses have to be cross-pollinated [Photo: Orlando Tomassini/ Shutterstock.com]

Some plants tend to only self-pollinate. Others cross-pollinate. But some can do both! Cross-pollination is by far most common, and in fact, most plants have evolved to prevent self-pollination because cross-pollination leads to adaptability. However, whichever type of pollination a plant uses says nothing about whether it is pollinated by insects, the wind, bats, birds or even water.

Expert tip: Several evolutionary mechanisms prevent self-pollination. These include: separate flowering times for the male and female flowers, as is the case for the hazelnut (Corylus avellana); structuring the flower so that pollinating insects will graze foreign pollen onto the plant’s stigma before collecting its own pollen; enzymatic self-sterility, where the pollen is either prevented from germinating or specialised enzymes stop the pollen tube in the pistil before it reaches the ovary.

In hazelnuts, the female flowers first appear after the male catkins [Photo: Mickis-Fotowelt/ Shutterstock.com]

Insect pollination

Many plants depend on insects for pollination. No prizes for guessing what this is called: “insect pollination”. All insect-pollinating plants are brightly coloured, strongly scented or otherwise characterised with features that entice insects. Incidentally, many plants are specialised for “their” pollinators – and the same applies for the insects. Flower shape and depth, nectar composition, the insects’ flight height and distance, the time of flowering and hatching of insect larvae are all precisely coordinated by the plants to optimise insect pollination. You are likely familiar with bee pollination. But butterflies, flies, moths and many insects are just as important.

Pollination by insects is one of the many different types of pollination [Photo: CaravanAtelier/ Shutterstock.com]

Examples of insect pollinators include: fruit trees such as apple (Malus), pear (Pyrus) and cherry (Prunus), lunkweed (Pulmonaria), arum (Arum), lime/linden (Tilia), chestnut (Aesculus), and meadow clover (Trifolium pratense), to name just a few!

Wind pollination

Wind is considered the original pollinator. In primeval forests, pollen was carried from plant to plant with wind alone. Wind pollinators can be recognised by their long, hanging catkins. The pollen in these catkins resembles dust, and is blown to the inconspicuous female flowers. These female flowers are often difficult to spot. They often lack petals or decorative features, leaving only stigma branches on which the pollen lands.

The male catkins of the willow hang down, while the female catkins stand upwards [Photo: Elena Kirey/ Shutterstock.com]

Examples of wind pollination: hazelnut (Corylus avellana), willow (Salix), alder (Alnus), birch (Betula).

For more information on pollination by bees, check out our special article.

The Joshua tree has a unique insect-pollinator, the yucca moth.

The bumblebee pollinates the morning glory in the cool beginnings of a new day.

And a gentle breeze is responsible for spreading the pollen of the spruce tree.

Tracey and I have learned that the moth, bee, and wind all act as pollinators for these plants. They are responsible for getting the pollen from the male part of the flower to the female part so that pollination can occur and a seed will form.

Although there are many different types of pollinators, there are just two main types of pollination—self-pollination and cross-pollination.

And today, we are having Summer come back to share a bit about pollination along with a summer science activity for you to enjoy!

Hi-ya, peeps! Ulysses and I are super excited to be back sharing another summer science activity with you guys!!

But before we share about self-pollination and cross-pollination, we want to share a bit about what happens when a flower is pollinated.

In pollination, the pollen lands on the pistil of a flower. Then, the pollen sprouts a tube down to the ovule, where the pollen and the ovule meet and join.

This eventually leads to the formation of the seed, which can grow into a new plant.

Self-pollination

In self-pollination, the pollen from the anther of a flower is transferred to the stigma of the same flower or the stigma of a different flower on the same plant. Then, pollination occurs and a seed is able to form.

This transfer can happen when the pollen grains literally spill onto the stigma, or the transfer can occur with the aid of a pollinator, like an insect, wind, or water.

The flowers of plants that use self-pollination to reproduce are generally much smaller.

Cross-pollination

In cross-pollination, the pollen from the anther of a flower on one plant is transferred to the stigma of the flower on another plant of the same species. Then, pollination occurs and a seed is able to form.

This transfer happens when the pollen is moved by an insect, by water, or by the wind. This type of pollination requires that there are two plants of the same variety in the area.

The flowers of plants that use cross-pollination are generally larger. The blooms also usually have a stigma that is taller than the stamens, which gives more of a chance for the pollen to spread to other flowers.

Pollination Activity

(Note – Ulysses and I have adapted the following from this F is for First-grade post.)

You will need the following:

• Several large paper flowers (Ones printed on 8.5 by 11 sheet of paper will work.)
• Several different colors of powdered cake mix, such as yellow, chocolate, and strawberry
• Several small printed bees
• Several craft sticks
• Several cotton balls
• Glue

Here is what you need to do:

1. Have the students each cut out and decorate a flower and a bee.
2. Next, have them glue their bees to a craft stick. After stretching out the cotton balls a bit, have the students glue one to the underside of their bees.
3. Sprinkle a bit of the yellow cake mix on the center of one of the printed flower, a bit of chocolate cake mix on another flower, and a bit of strawberry cake mix on another flower. This will act as the pollen from the flower.
4. Now, have the students use their bees to go from one flower to another to pollinate each one.
5. Afterward, have the students observe what has happened to the cotton balls on their bees and the centers of their flowers.

Here is what should happen:

The students should see that their bees have picked up each type of pollen from the flowers. They should also see that the pollen on their flowers has been spread out and mixed up. The same happens in insect-driven cross-pollination.

Here is what we have learned from Summer:

• Self-pollination is simple, as it only requires one plant of a given species for reproduction.
• Cross-pollination is a bit more complicated, but it allows for a greater variety within a species.

And here are a few books you can read about pollination:

• What If There Were No Bees?: A Book About the Grassland Ecosystem by Suzanne Slade and Carol Schwartz
• What is Pollination? (Big Science Ideas) by Bobbie Kalman
• From Seed to Plant by Gail Gibbons

Now go outside and see some pollination in action!!