Hypothesis

There will be differences between the pollen found in plants of urban environments and plants of mountainous environments.

Phylogenetic Tree Based on Sequencing

Designed by Joe Kilty

All of these plants were sequenced using the matK gene, because that was the first one we found that all of our plants had in common. In our tree, Monotropa hypopitys represents Indian Pipe, Rosa acicularis represents a Rose, and Adiantum capillus-veneris represents the Sword Fern. As to how the two tables compare, our hypothesis about the Indian Pipe being more closely related to the Sword fern was correct.

Phylogenetic Tree Based on Pollen Morphology

Designed by Joe Kilty

We arranged our tree in this way (The Sword Fern being less closely related to the other two species) because the Fern reproduces using sperm, not pollen. This factor immediately makes the Rose and Indian Pipe more closely related. The shape of the pollen from the Rose and Indian Pipe is vaguely similar, with the apertures being located in nearly the same places and a similar surface texture. The Rose is probably closer related to the sword fern. There are many more species of Rose and that signifies that it is older.

Background Image Credit

Sword Fern
Indian Pipe 
Rose

Experimental Question Analysis

We were able to obtain sufficient data to accurately answer our scientific question. We did this with the Scanning Electron Microscope and a special Leica microscope equipped with a camera. Our data shows that there are different shapes and sizes incorporated in the designs of pollen. For example, the pollen from a rose has a poliplicate structure, and this is because they need to be able to reproduce more easily. The pollen of the indian pipe (Monotropa uniflora) is harder to determine. Based on our sample, the pollen might not even have a pore. This changes based on how they reproduce, where their habitat is, and other factors. Our pictures show that when you move to a different environment, the pollen shape and size tends to change. One thing we had trouble with was obtaining and placing the pollen samples for viewing in the SEM. A little more practice would have been nice, because there is always room for improvement. However, we were able to quantify and collate the data we obtained in a way that allowed us to accurately answer our question. When a plant species lives in a certain environment, that environment influences how the pollen looks. A possible error that could have occurred is that while indian pipe and roses reproduce with pollen, sword ferns do not. They use sexual reproduction, which we were not aware of at the front end of our experiment. 

Background Information

Rose

• Roses, an extremely popular flower, have many different varieties (100 different species) that grow all over the world.
• They originated in Asia.
• Different types of roses can range from a few inches high to several meters tall.
• They are most commonly used for fragrance and decoration.
• Many wild roses are host plants for many pests and diseases.
• The thorns of a rose are technically called prickles.
•  Roses contain several ovaries in one flower rather than one.
• Pollen in found in the anther of a rose and is usually colored yellow.

sources:

one, two

Indian Pipe

• The Indian Pipe is also known as corpse plant.
• This plant doesn’t have chlorophyll.
• Indian Pipes usually grow 4-10 inches tall.
• It is often confused to be a fungus.
• Indian Pipe grows in shady woods.
• They are often found near decaying stumps.
• Indian Pipes take nutrients from trees and fungus.
• It grows in densely shaded pine wood forests.  
• They will usually have 4-6 petals and 10 stamens, which are pollinated by insects.
• After fertilization, the flowers will point upwards and turn black.

sources:

one, two

Sword Fern

• To reproduce, the sword fern grows a small heart shaped plant called, prothallium. Prothallium has egg cells and sperm cell and when the climate is wet enough, they combine together to create a new Sword Fern.
• Ancient plants that evolved long before plants had flowers.
• Sword Fern grow from 50 to 180 centimeters.
• They grow best in coniferous forests.

sources:

one

Procedure

1) When preparing a specimen for viewing in the SEM, you have to go through a few steps before you’re ready. Our first plant (Monotropa uniflora, or Indian Pipe) was a bit tricky to prepare. After we found the pollen grains inside the flowers, we used a small paintbrush to apply the pollen to the carbon tape. The other two specimens, Rosa and Polystichum munitum (Red Rose and Sword Fern, respectively) were much easier to prepare.

2) Using a Leica microscope that was able to capture images, we took a few pictures at 35x magnification.

These photos are showing the spores on pollen for sword fern (above) and indian pipe (below).

3) We used a growing solution made up of 0.1% boric acid and 30% sucrose. While our pollen didnot end up growing pollen tubes, we still were able to draw a few pictures of the pollen samples on the wet mount slides.

The leftmost circle shows a drawing of the indian pipe pollen at 400x, middle circle shows a drawing of rose fern pollen at 400x, and the rightmost circle shows a drawing of fern pollen at 400x. (Artwork by Fiona Gredvig)

4) During our time using the SEM, we were looking specifically for differences in pollen types.

These were our three test plants, and here is what their pollen looked like under the SEM FEI Phenom Pro.

Photos to the left show the plants in their in situ phase, and photos to the left were taken with the SEM to show the pollen after it had died and dried out. 

These are the three test plants that we studied. In the left column are picture of the actual plants. That is what they would look like if you found them growing in the wild. In the right column are pictures of the pollen under the SEM. The green measurements on the SEM photos signify how big the pollen is in Micrometers.

Photo credit:

sword fern

indian pipe

red rose