Methods For Viewing Pollen Under The Microscope

Pollen is a feature of most everyday of our life. Whether you wake up to find your car covered in pollen, or you’re walking around a park and find yourself sneezing and spluttering, pollen can very often be the cause of these problems!

Methods For Viewing Pollen Under The Microscope

While pollen is a nuisance, it is also a very interesting and intricate part of nature and it really is fascinating to view under the microscope!

There are many different ways to view pollen under the microscope, and you will find that you see very different things with each of the methods.

This article will explore all of these methods, so that you can start exploring the pollen world using your various telescopes! 

What Is Pollen?

Pollen is a yellow dust which is made up of some cells which create a grain. It is usually dispersed by wind or insects, such as bees. It can also sometimes be dispersed by other means, such as humans or other animals. 

The grains that pollen is made up of are very small and can only be seen under the microscope. Pollen is released from the male part of the flower and contains the ingredients needed to fertilize the female part of the flower – the ovule.

As mentioned, the pollen reaches the ovule when it is transported by the wind or animals. 

Pollen is created in the flowers of a plant, in the sacs which are inside the anthers. During the process, a pollen is created which is the male reproductive seed. 

How Does Fertilization Of A Plant Work?

When the pollen is transported through the wind and animals to the female ovule, it will begin absorbing water, which, in turn, means that the pollen grain will become active.

When the pollen becomes active, the gametophyte within it will start to form a tube which leads the way to the ovule – the female reproductive part of the flower.

When this happens, the male cells can move to the female cells to allow them to fertilize.

How To Look At Pollen Under The Microscope

When you have collected your pollen, it should be used immediately or you can freeze it. 

The procedure for how to study pollen under the microscope will be different depending on the type of microscope you are using. 

Pollen Microscopy

In order to study pollen under the microscope, you will need the following tools:

  • Needle 
  • Pipette tips 
  • Tweezers 
  • Microscope

A pollen microscopy is a great way to study and identify the types of pollen. 

Procedure

The procedure for using a pollen microscopy is quite simple. 

  1. Collect the pollen grains. In order to get these in this case, you should collect healthy anthers from certain flowers. You want to make sure that you use flowers with a healthy and high pollen count. 
  2. With your needle, you should scrape the anthers to remove the pollen, and place this inside the tube or pipette tip.

Looking At Pollen Under A Stereo Microscope

What Is A Stereo Microscope?

A stereo microscope is a certain type of microscope which gives a 3D view of what you are viewing.

Also known as a dissecting microscope, this microscope has different eyepieces and objective lenses, meaning you can look through different lenses in each eye. This is what creates the 3D view. 


What You Will Need

In order to study pollen under a stereo microscope, you will need the following: 

  • A stereo microscope
  • 50 percent glycerine 
  • Alcohol 
  • Microscope slide 

The reason it is advised that you have alcohol is because it is good to look at treated and untreated pollen to compare the similarities and differences between the two. In order to treat the pollen, you should wash it with a small amount of alcohol.

The reason it is good to get a look at the pollen after it has been treated with alcohol is because sometimes the oily surface of the pollen means that you can’t see clearly. 

Procedure

In order to study pollen under a stereo microscope you should follow the steps laid out below.

  1. Firstly, you should wash the pollen grains using the alcohol as explained above. 
  2. Next, you should place the pollen sample that you are hoping to study on the slide.
  3. When you have the pollen on the slide, you should add 50 percent glycerine to the pollen sample. 
  4. Place the slide under the stereo microscope and start viewing the pollen.

Looking At Pollen Using The Glycerol Jelly Method Using A Compound Microscope

The glycerol jelly technique is the most popular method to study pollen. This method requires quite a few different pieces of equipment compared to the methods explored above. You will need:

  • Pollen sample that has been collected the same day
  • A compound microscope
  • Alcohol solution
  • Water 
  • Glycerine jelly 
  • Microscope cover slips
  • Glass slide
  • Distilled water

What Is Glycerol Jelly?

Glycerol Jelly is made up of a few different ingredients which come together. In order to make glycerol jelly, you need to mix together distilled water, glycerol and gelatin. The ratio is as follows: 

  • 10 grams gelatin
  • 35ml distilled water
  • 30 ml glycerol

When you are using this method for studying pollen, it is always better to use pollen that you have collected that day.

Procedure 

  1. Add some of your pollen to a small dish. Place in some of the alcohol solution and leave it to sit for ten minutes. This will ensure that you have a better view of just the pollen, also removing the oily layer from the grains.
  2. Add some warm water to your glycerine. This will allow it to melt.
  3. Place a couple of drops of your pollen and alcohol mix on your glass slide. 
  4. Add this slide to a hotplate. This will allow the mixture to dry. 
  5. When it is dry, place the glycerine jelly (one drop) to the cover slip of your microscope and lower it onto the slide. Ensure you don’t get any air bubbles into the slide here, and ensure that the jelly and the pollen touch.
  6. Place the slide on the hotplate again for around 5 minutes. When you do this, you will allow the glycerine to mix with the pollen grains.
  7. You then need to put the slide aside to allow the jelly to set. It should be left in a cold area. You can use these slides for months if you seal up the edges with nail polish.
  8. Once the jelly has set, you can get viewing!

Why Go To All This Trouble?

When you use the glycerol method, you will get a much better view of the pollen through the microscope.

The stained slide is the side that will give you the best view of the pollen, as it is clearer due to a better level of contrast. You will see little pollen grains that look like they have a very scaly surface. 

Compound Microscope – Wet Mount Technique

What Is A Wet Mount Technique?

Wet mount slides are slides that are prepared using certain liquids placed in the slide with the sample. These liquids are used to allow the sample – in this case the pollen – to move and interact with during the observation. 

For this technique you will need the following: 

  • Glycerol
  • Cover slip
  • Dropper
  • Glass slide 

Procedure

For this technique of viewing pollen under the microscope, the following steps should be followed:

  1. Grab your glass slide and add two drops of your glycerol to it.
  2. Add the pollen
  3. Place the cover slip on the pollen sample. Make sure that you are adding this at an angle in order to remove any air bubbles. 
  4. Again, in order to store the prepared slides, seal up the sides of the slide with a little bit of nail varnish. 
  5. Get viewing! 

Why Use A Wet Mount?

Usually, people use wet mount slides to view live samples. For instance, when you are studying bacteria, these are great to study using a wet mount.

You can either study samples that already live in water or whose movement is easy to detect when placed in water.

For bacteria, if you observe them under a microscope using the dry mount slide method, the bacteria won’t have the opportunity to move around.

Under a wet mount slide, this bacteria moves much more easily and will be able to move around more.

Dry Mount Method – Using A Compound Microscope

Dry Mount Method - Using A Compound Microscope

This method is super easy and doesn’t require much! All you’ll need is a slide, the sample and the microscope. Follow these steps to carry out the dry mount method:

  1. Place your pollen sample onto your slide. 
  2. Cover the sample using the cover slip.
  3. Get viewing!

When To Use A Dry Mount Technique

While making up dry mount slides is very easy, they are not always the best option to go for. These mounts are temporary, so you will have to make up a new one each time you use them.

They are also not as good for viewing and you will not see as many of the intricate details as you would on a wet mount.

Electron Microscopy

Electron microscopy is a lot more complicated than some of the methods that we have explored above. For electron microscopy, you will often use acetolysis to prepare the pollen sample.

Sometimes, however, this method is not the best option, as it has been shown to cause distortions. That is why the newest method of aerosol-OT and amyl acetate are the best options to use here. 

For this method you will need:

  • Pollen sample
  • Water 
  • Ethanol
  • Amyl Acetate 
  • Aerosol-OT 
  • Pipettes
  • Centrifuge tubes
  • SEM microscope (scanning electron)

Procedure 

So, if you want to use this method, follow these steps:

  1. Remove the anthers from the flowers and add 3% aerosol-OT solution to them to allow them to soften.
  2. Remove the pollen from these anthers and put them into a centrifuge tube. 
  3. Leave the pollen in the solution for at least 5 days to allow them to rehydrate.
  4. Get rid of the aerosol-OT solution and add some water. 
  5. After 10 minutes, drain out the water. You should then add the acetone mixture, which can be left for up to an hour. After this step, there should be nothing else on the surface of the pollen.
  6. Remove the acetone and then add some distilled water to the mixture and allow this to stand. This should be left for around 10 minutes. 
  7. Remove the 50 percent ethanol and add the 70 percent ethanic and leave this for an hour. 
  8. You will then need to replace the 70 percent ethanol with the 90 percent ethanol and allow this to stand for an hour. Repeat this process, replacing the 90% ethanol with 100% ethanol. You should add the 100% ethanol mixture twice. 
  9. Drain out the ethanol from the mixture and add amyl acetate to ensure that they are properly dried out. 
  10. At this stage, you should remove the pollen grains from the tube where you have been adding and removing the liquids, and move them into a BEEM capsule. 
  11. Add the cap to the cylinder.
  12. Remove the amyl acetate from the solution, and you should be left with the pollen. 
  13. Move the pollen grains into the basket. 
  14. You will then have to add the baskets to a critical point dryer. After this, you should remove the lid of the cylinder and mount the grains. 
  15. Get viewing!

This is a much more complicated process for viewing the pollen grains than any of the others listed above, however, it creates a very clear view of the pollen under the microscope.

What Will You See?

When you are using this method of viewing, you will see the grains very clearly as various shapes. They have rough surfaces, and some types of pollen will have deep ridges.

The difference in what you will see between this method, and the compound or electron microscopes is that you will see little parts of the detail in the grains but you will not see it across the whole thing.

This method will allow you to see them across the entire pollen grain.

Frequently Asked Questions

What Level Of Magnification Do You Need In Order To View Pollen?

Pollen is a very complicated thing to look at under the microscope and there are many different things that you could be looking for.

Most pollen requires between a 10x or 40x magnification on the objective lens in order to be able to see any detail on the pollen.

For the fine details, you will need to be more towards the 40x objective lens in order to be able to see much.

What Will The Pollen Look Like Under The Microscope?

When you view the pollen under the microscope, you will see different things depending on which of the methods you have chosen to use.

You will see varying degrees of irregular structures that are strangely shaped and come in different shapes and sizes.

The pollen that you are looking at will have a large impact on what you are seeing, as pollen comes from all sorts of different plants, flowers and trees. All of these produce varying types of pollen.

What Is The Importance Of A Microscopic View?

Microscopes teach us so much about the world around us! There is so much that we wouldn’t be aware of if we didn’t have the ability to to use a microscope.

They give us a new way of looking at certain things and give us a new perspective on these things. As our knowledge and understanding develops, we come to understand more and more about what we are looking at.

What Are The Different Types Of Pollen?

There are many different types of pollen. There is the pollen from the tree family, which consists of birch, oak and pine pollen.

There are also tree pollens and weed pollens. There are 30 different types of pollen, all of which can cause allergic reactions.

When Is There Most Pollen Around?

The highest pollen counts are usually around June to October. This is true of both weed and grass pollen. Tree pollen is released earlier in the year – around January to April.

What Are The Different Types Of Microscope?

There are five different types of microscope. These are the simple, compound, stereo, confocal and scanning electron microscopes.

They are all useful in different ways so before you buy your own microscope, you should do some research on what you will be using yours for and which one will best suit your needs.

The ways to view pollen that we have explored in this article use different types of microscopes.

Final Thoughts

So, there are plenty of different ways to view pollen grains under the microscope, and each one is really worth a go. Some methods are a lot easier than others but they all have their own pros and cons. 

With these methods, you can transform your understanding of pollen from just that annoying thing that makes you sneeze to something so intricate and detailed!

Jennifer Dawkins

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