Friday, June 3, 2016

Roses - More Beautiful Up Close

The landscaping here at Eastfield College is well maintained and can be unexpectedly beautiful.  I was involved in a student/faculty mixer recently and set up a dissecting microscope with a large screen display for students to use.  At the last minute I dashed outside to see what extra samples I could find and brought back in some roses.  In the process of pulling the roses apart and putting them on the microscope I began to see some really beautiful structures.

These are" knock-out roses" which do well in our hot summer climate, bloom continuously, and are very disease resistant.

[Let me say up front that I am a bit color and color name challenged, so my descriptions below may not exactly agree well with what you see.  When I say red it could actually be pinky-red or dark pink, or . . . well, you get the picture.  I refer to the colors to give landmarks for naming structures.  It should be close enough for you to see what I mean.]

OK.  Big Deal.  Red roses and green leaves. Not so fast.  I took some flower buds and open flowers back to the lab to image.  What I found might surprise you.

The images below were made with a dissecting microscope with a digital camera.

The image above shows a longitudinal section of an unopened rose bud.  Flowers are actually modified leaves.  The parts of a flower grow in circular whorls.  The outer most layer are the sepals, which surround and protect the developing flower; then the petals, for attracting pollinators; the stamen, or male parts of the flower that product the pollen; and in the middle the carpel, or female part which contains the eggs.  The swollen part of the stem below the flower parts is the ovary.  You can see several ovules in the ovary, each of which contains a single egg that could become a seed.
This is a close up of the ovary.  The seed-like structures are ovules which hold the eggs.  You can see the filamentous styles leading from them to into the flower.
Here is a close up of the unopened flower bud.  Just inside the reddish petals are the developing stamen and in the center are the carpels with a blush of red on them.
This image shows the stamen of a newly opened flower bud.  The anthers have not yet split open to begin releasing pollen.  The colors really surprised me.
This image is a closer look at the maturing anthers. I really love the colors in this image, no matter what their names might be.

This is a fully opened and mature rose flower.  The green carpels that protected the unopened bud are seen below the petals.  Above the petals are the pollen-producing stamen and in the center the red structures with the yellow tips are the stigma and style - two of the female parts of the flower.

On the right side of this image you can see the pink filaments that support the anthers.  The anthers produce the pollen.  A close look at the top right will show some anthers that have broken open to show yellow pollen.  The left side of the image is the top of the female part of the flower.  At the bottom is the ovary (not shown).  The pink/red filaments are the styles - they connect the yellow tips to the ovaries.  The yellow tips are stigmas.  When pollen grains land on the stigma they germinate and grow a tube all the way down to the egg in the ovule.  The two sperm cells formed in the pollen grain will make their way down the tube to the ovule where one of them will fertilize the egg.  Plant sex turns out to be very weird.  Look up "double fertilization in angiosperms" on Google.
Yellow stigmas on top of styles.  Some of the yellow spots are pollen grains.

Here are mature anthers at the ends of their filaments. You can see the yellow pollen grains emerging from the edges of the anthers.

This is the edge of the unopened flower bud.  Male anthers on the left, then the stacked petals, then the surrounding sepals.  Being a rose, there are thorns. The small thorns on the outside of the sepals have secreted some reddish liquid.
More thorns secreting reddish liquid.  The base of the ovary is at the top of the image.  Note the red blush on the thorns.
Here is a fully developed thorn from farther down the stem.  The drop of liquid is gone, but the red blush is still there.
This is the underside of a rose leaf.  Most obvious is the serrated margin of the leaf.  You can also see the veins of xylem and phloem that carry water and sugars.  Again, there is red blush everywhere.

This image is a close up look at a vein on the underside of the rose leaf.  I have illuminated the leaf from the bottom.  The outer layer of cells on the vein are pigmented.

The images below were made with a scanning electron microscope.  Unfortunately, these images are in black and white, but the structures are still interesting.

A rose petal feel like velvet when you touch it.  In the image above you can see why.  The petal is made up of thousands of raised cells.  Magnification = 131 x.

Here is a closer look at the cells that make up the rose petal. Magnification = 1,110 x.

When roses carry out photosynthesis, they take in carbon dioxide and use it to produce sugars.  A by-product of carbon dioxide is oxygen (thank goodness).  The image above is of the underside of a rose leaf.  It shows the mouth-like stomata that allow gases to move into and out of the leaf.  Magnification = 650 x.
I wanted to see what the pollen of the rose looked like.  Here is a view of an anther (left) with the pollen grains spilling out (right).  Magnification = 450 x.

Much to my surprise, the cells that make up the anther are highly folded.  Their structure is pretty amazing.  Magnification = 950 x.

Using microscopes to see the small beauty of roses reminds me of a one of my favorite quotes from Henri Poincare, a French mathematician from the late 1800s.

"The scientist does not study nature because it is useful to do so. He studies it because he takes pleasure in it; and he takes pleasure in it because it is beautiful."

Best wishes from the Eastfield College Microscopy Lab.

Murry Gans

Please feel free to use images from the lab for non-commercial purposes and please give credit to the Eastfield College Microscopy Lab, Mesquite, TX.