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.

Monday, March 7, 2016

Why Are Insects So Successful?



I really like insects and read about them a lot.  In my reading, I came across the remarkable fact that there are an estimated 10 quintillion insects on Earth. Here is that number written out.

10,000,000,000,000,000,000 

That is 10,000,000,000,000,000,000 individual insects comprising more than a million different species. Compare that to 7.3 billion people on the planet, all in a single species, and it turns out that for every man, woman, and child there are more than 1.3 billion insects.  (If insects creep you out, sorry about that.)

(A super cool website is the live population clock of the US Census Bureau - check it out at http://www.census.gov/popclock/)

So why are insects so successful?  I attempted to write an answer to that question and was lucky enough to have had TED-Ed produce what I wrote.  I hope you will take a look and let me know what you think.



M. Gans
Eastfield College
Mesquite, TX

Tuesday, February 23, 2016

Early Spring Tulips


The folks here at Eastfield College who keep our campus beautiful have given us a real Spring  treat. They planted thousands of tulip bulbs which are coming into full bloom.  (There are also lots of white daffodils.) I want to make sure everyone at the college knows where they are so they have a chance to see them.  See the campus map below, but don't wait - they won't last for long.


Red arrows indicate location of bulb beds.  
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I went out to take some pictures, but also to bring a flower back to the lab for imaging.  Once I saw them I just couldn't bring myself to pick a flower, so instead I reached in and removed a single anther - the pollen-producing structure of the flower.

The anther of a tulip.  At first glance they appear black, but on the dissecting microscope you can see the multicolored pollen grains.

Here is a close-up of the pollen of the tulip.
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Now lets look at pollen using the scanning electron  microscope.

This is a cross-section of the anther.  It is a little flattened by the cut with a razor blade, but you can clearly see the pollen grains on its surface. [25x]
This is a closer look at the center of the structure shown in the image above.  I don't know what the sac-like structures in the image are, but their shape was too interesting to not show. [200x]

These are some pollen grains from the tulip.  The are pretty crushed down from the high vacuum of the microscope.  Note the texture on the surface of the pollen grain.  [370x]

This pollen grain is the target for the next image.  It is about 75 microns long.  That is 75/1,000,000ths of a meter. [800x]
A close-up of the surface of a single tulip pollen grain magnified 15,000 times.  To give you some sense of scale, an E. coli bacterium is about 3 microns long.  The scale bar in this image is 2 microns.
Living in Texas, and getting a bit older, I really don't like the cold so it is really nice to see flowers in bloom.  If you work at Eastfield, you have my permission to take a short break an head outside to see the show.  Happy Spring!

All images are under the Creative Commons Attribution, Non-commercial License.  Copy, modify, and use them all you want, just please give the lab credit.












Tuesday, May 26, 2015

In Defense of an Invasive Species - Fire Ants





Solenopsis invicta Buren - The red imported fire ant. 
A head-on view showing the jaws and teeth.  I like the next image more, but lots of people who visit the lab seem to really like this one.

Head view showing some of the diagnostic characteristics used to identify the red imported fire ant.

My lab recently began a project to collect and catalog all of the species of ants in several counties in eastern Texas.  As a result, I spend a lot of time hunting for and watching ants. 

In Texas we have a big problem with the red imported fire ant, Solenopsis invicta. Fire ants bite and sting.  When disturbed they give off an alarm pheromone and go crazy.  They grab hold of your skin or clothes with their jaws to get the leverage they need to jab their stinger into you.  Find yourself standing in the wrong place and you can have a rather unhappy experience.  (In one case I was watching some beetles mating on a flower and was standing on a fire ant mound.  They let me know about it.) 

In February and March my students and I began developing methods for using baited traps for our research, and the only ants that were active in late winter/early spring were fire ants.  They were great for our experiments. We didn’t disturb their mounds because we wanted to take advantage of their normal foraging behavior.  Leaving the mounds alone and taking a second to look before I put my hands and knees down pretty much eliminated getting stung. Duh!

The fire ant is a classic example of an invasive species, a non-native or alien species in an ecosystem which causes economic harm, environmental harm, or harms human health. (1) Introduced into the United States through Mobile, Alabama in the 1930s, these little ants have spread to nine states, covering 260 million acres.  (2)

Fire ants cause lots of problems. They pile into electrical boxes, displace other ant species, kill small animals, make a certain proportion of some crops unharvestable by combine, and aggressively defend their territory, even if you are the one who owns that territory.  For the 1% of the human population that is hypersensitive, they can be a major health problem.  (2, 3)

But I would like to stand up for the fire ant just a little.  It is not the demon menace sent here to make our lives miserable; it is doing exactly what it is supposed to do – competing with other species for available resources in the environment and passing its genes on to the next generation.  

Think about that first fire ant colony that got accidentally (I hope) shipped into Alabama.  No species is simply going to say “Oops!  I don’t belong here so I am just going to stop eating and stop breeding.”  They are going to fight to survive by competing for what they need and spreading into any new habitats that will support them. That is how species survive.  It is, by the way, exactly what humans do, too.

But what about all of the other species that fire ants have displaced or adversely affected in some way?  Isn’t it unfair and that these mean old fire ants came and replaced them? 

It isn’t a matter of fair or unfair – it is natural selection.  Limited resources mean that the species that most successfully competes for those limited resources survives.  There is no fair or unfair in nature; there is only survive or go extinct.

Why are invasive species so bad?  They are bad because we humans have officially and legally said so.  It is very much like the difference between a weed and a wildflower.  If it is growing in a field, a plant with a pretty flower is a wildflower, but if it is growing in your yard and sticking up out of the grass, it is a weed.

Look back at the description of an invasive species and notice that it involves three things – harm to the economy, human health, or the environment. The first two are directly related to the effect that any species has on us.  And harm to the environment?  Fire ants do decrease biodiversity, but they are not an oil spill or a destroyed nuclear reactor.  They don’t kill and displace everything. They interact with the other organisms in their environment, for good or bad.

It is also important to remember that for millions and millions of years, species have been moving from one ecosystem to another, sometimes across thousands of miles of ocean.  The competition between native species and invading species is as old as life.  Successful invading species become native species. (4)

But I suspect that the main reason that most people don’t like invasive species is because humans don’t like change.  In fact, we downright hate change.  Why can’t things just stay the way they always were?  If you are talking about living things remember – to stay the same is the very best way to go extinct.

Until I started this research, like most people in our area, I would have told you that I hated these little suckers, but I am slowly changing my mind.  I am not saying that I like fire ants or am even the slightest bit happy about sharing my environment with them, but I do greatly admire their adaptability.

The business end of the fire ant - the stinger.

The stinger of the fire ant magnified 1000 x.  Notice the backward facing barbs on the stinger.  Ouch!!
The 10 segments of the fire ants antenna.









References:    

(1) What is an invasive species? (2012, November 18). Retrieved May 5, 2015, from National Invasive Species Information Center website: http://www.invasivespeciesinfo.gov/whatis.shtml 

(2) History of the red imported fire ant. (n.d.). Retrieved May 26, 2015, from

(3) [University of Florida]. (n.d.). Retrieved May 26, 2015, from Featured Creatures website:

(4) de Queiroz, A. (2014). The monkey's voyage: how improbable journeys shaped the history of life. New York, NY: Basic Books.

Friday, January 2, 2015

Yonley's Bark


I know what you are thinking - what the heck is a Yonley?

Dave Yonley is one of my amazingly talented colleagues here at Eastfield College.  Dave is a videographer/film maker for the college and does truly outstanding work. (He even makes me look good!)

A few weeks ago Dave was on vacation in sunny Florida, walking around and taking in the sights - the ocean, the beaches, and the palm trees.

One of Yonley's photos from Florida
Dave came across a piece of bark that had fallen off a palm tree and decided to bring it back to Texas. He gave me some of it for my microscopes.

This is Dave Yonley.  He really doesn't like to be photographed, which is kind of ironic since he spends his work day filming other people, but I conned him into posing with his palm tree bark.
What caught Dave's eye was the pattern of the cellulose fibers that make up the bark.  Even in the picture above you can see at least two distinct layers of fibers produced at 90 degrees to each other. This makes the bark extremely strong.

This is the underside of the bark.  Note the wide strips - probably where it was attached to the tree, and the thinner fibers in different layers. [Camera image - taken outside]
Another view of the underside of the bark.  At first glance it looks like fabric, but unlike fabric, the fibers are not interwoven. [Camera image - taken outside.]
This image was taken with a dissecting microscope.  You can see that the flattened strips of bark also contain fibers.


Here is a look at the stringy fibers deeper in the bark.  
Scanning electron microscope view of the stringy fibers. Notice the wide range of sizes. [SEM image; 30x]
The diameter of a human hair is about 80 microns.  Here you can see that some of these fibers are smaller than a hair. [SEM image; 369x]  By the way, a micron, the unit on the image, is one-one millionth of a meter.
Scanning electron microscope view of the flat strips on the underside of the bark.  [SEM image; 218x]

In this image you can begin to see the cells that make up the structure of the bark.  [SEM image; 129x]
The cells to the left of the image divided in a flat plane.  To the right of the image is a fiber which, as you will see farther down, is formed by bundles of cells.  [SEM image; 450x]
Now, let's flip the bark over and take a look at the outer layer.

The top of the bark has an extra layer of fuzzy fibers.  

A closer view of the outer layer of fibers.  

Scanning electron microscope view of fuzzy fibers.  These look very much like the trichomes found on the leaves of many plants. [SEM image; 45x]
At this magnification you can see that these fibers are composed of strands of single cells, not bundles.  [SEM image;  [750x]
To show the composition of the palm tree bark, I cut a small section with a razor blade and then mounted it edge-on.

This edge-on view of palm tree bark is a composite of two pictures.  The fuzzy layer is at the top. Below that area several layers of fibers of different sizes laid down at right angles.  At the very bottom of the image is a flat layer.  [SEM image; 30x]
Cross-section of topmost fuzzy layer.  [SEM image; 50x]
Cross-section of fibers with fuzzy layer at the top of the image.  The red arrows indicate the single cells that make up the fuzzy layer.  [SEM image; 140x]

Cross section of a fiber showing the arrangement of individual cells.  The bundle is slightly flattened from being cut with a razor blade.  [SEM image; 300x]
What Dave found intriguing was the amazing strength of the sheet of bark collected from the palm tree, a strength resulting from many small, cellulose fibers being laid down in different directions. 

Natural, super-strong structures like this, the result of evolution and cell division, have obviously influenced the development of human-engineered materials including fabrics, ropes, and even steel cables.  Not bad for a palm tree.

The images in this blog are covered by a Creative Commons License.  They may be downloaded, used and/or modified for non-commercial purposes.
Murry Gans
Eastfield College
Mesquite, TX