Pollination

Just a little note before I start:

This post starts the beginning of my ‘back to basics’ in the garden. I decided to have this heading in my blog not only for my followers who are just starting to learn about gardening but also for those of you who might need to recap over certain areas, maybe learn a new fact along the way. I’m a great believer in that as humans we never stop learning so let’s get started by untangling those garden roots and finding out all about gardening!

 

What is pollination?

Put simply, it’s the movement of pollen grains by a pollinator, from the male part of the flower (called the anther) to the female part of the flower (called the stigma).

It is an important and essential process that takes place, more often than not unnoticed whilst we go about our daily lives and chores.

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The stigma (left) and anther (right) of a butternut squash. You can just about see some pollen on the anther!

Why does pollination occur and is it important?

The end product of pollination is the formation of seeds. These seeds are the offspring of that plant. Pollination has to take place in order for future generations of our plants to continue to exist, without this it’s not only a bleak future for a great majority of plants but also for humans too!

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Take a moment to think about what you may eat or wear on a day to day basis. I can guarantee that at some point plants and pollination will have been involved. Are you wearing a cotton shirt that started life as a cotton plant? Did you have milk on your cereal this morning? Yes OK, milk comes from a cow, but what does the cow eat? Grasses that need to be pollinated! Some of the medicines in your bathroom cabinet may have been created after the discovery of medicinal compounds found from certain plants. The list is endless but even with the few examples above, it highlights the importance of plants and of pollination in our lives.

There are two types of pollination

Self pollination: takes place when pollen grains from an anther are put on the stigma of the same flower or on a flower that belongs to the same plant.

Cross pollination: takes place when pollen grains from an anther are put on the stigma of another flower of a different plant but which is of the same species.

Who are the pollinators?

In order for pollination to occur there has to be a pollinator, or in other words, a pollen carrier.

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Wind is an effective pollinator of grasses.

Wind is an example of a pollinator, but one that nonchalantly blows pollen in which ever direction it is travelling. Other pollinators are found in the animal kingdom and are more precise when it comes to transferring pollen.

Pollination is a ’round the clock job’ with a majority of pollinators performing their ‘duties’ during the day shift and a minority preferring the night shift. Bees are notably the most proficient and effective pollinators during the day but that’s not to say that butterflies, ants, beetles, birds and even humans don’t contribute their little bit! At night, it is bats and moths that take over from the day shift.

Please note that whilst gardeners go out of their way to intentionally pollinate their flowers, the pollinating ‘duties’ of insects, birds and other mammals on the other hand are secondary to their primary reason for being on the flower in the first place, which is to find food. As the insects move along a flower in search of something tasty, they are unintentionally picking up pollen on their bodies and then dropping it off onto another flower in their continued quest for food, completely unaware of their importance in pollination.

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Look at how the pollen clings to every part of the bee’s body.

How do flowers encourage pollinators to visit?

Flowers are clever little things and have evolved over time to be the best they can to attract pollinators. Some examples are below:

  • They can be rich in nectar to encourage hungry mouths.
  • The shape of the flower may have evolved over time to suit the pollinator or in some cases the pollinator evolves so that it is able to reach the nectar at the base of a flower. An example of this was a moth that was discovered in Madagascar, whose tongue had elongated over the years to enable it to retrieve an orchid’s nectar.
  • Beautiful and attractive flowers.
  • Fragrant scents which are great for poor sighted bees who use smells to guide them. There are some plants, however, who are well known for releasing pungent, nasty smells to attract flies.
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What bee wouldn’t love this!

Do we need pollinators?

Yes, absolutely in order for pollination to continue to occur and for future generations of plants to exist. Wind as a pollinator can be a bit unreliable unless of course you live in an area where there are constantly blowy weather conditions! Humans also are somewhat unreliable and would not be able to complete pollination duties as effectively as bees and other insects, for one thing it would take us too long to finish. Could you just imagine finishing your job for the day and then going home or to a field to help pollinate? We have enough to do in the garden as it is. This is why our little garden pollinators are so invaluable to us and deserve a lot of respect for what they do!

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Some examples of barriers to effective pollination:

  • Bee numbers have unfortunately been noted to be declining over the years as a result of insecticide use, destruction of bee homes in the wild for building and farming as well as pollution and climate change. It’s time for us to all do our bit and help save the bees. If you are interested in finding out more there are plenty of reliable websites to guide you in the right direction.
  • Greenhouses can be enormous obstacles for tiny insects, even if you do have the door and window open. It’s certainly not easy for poor sighted fliers and if you hit a window pane a few too many times, you also would avoid that area for a longtime. In these circumstances you may need to help pollinate flowers that are growing in the greenhouse. Did you know tomatoes in particular need wind or bees for pollination? Something to be aware of if you grow tomatoes in your greenhouse!
  • Have you ever grown pumpkins? If not, pumpkin plants have separate male and female flowers.
    pollinationC

    Female pumpkin flower with visible fruit.

    If you have, you probably already know that male flowers only live for one day and then die. You may also have experienced like me that by the time you have spotted a female flower that has the tiny pumpkin fruit on, you may be lacking in the number of your male flowers.

    pollinationB

    Male pumpkin flower.

    This can reduce the chance of pollination significantly and so this is where human pollinators are going to increase that chance by getting involved. I can often be found in pumpkin growing season trying my best to imitate a bee and taking the pollen from the anther and rubbing it on the stigma!

 

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