Category Archives: photosynthesis

Superphotosynthesizer: Cat Island Baldcypress

Today May 18, 2015 is ‘Fascination of Plants Day,’ an initiative organized by the European Plant Science Organisation with other events organized by the American Society of Plant Biology. On this blog, there’s no shortage of reasons why plants are fascinating, but to most they are still just the scenery. Take some time today to consider all that these primary producers do for you. Here are just a few things plants do for us- food, forestry products, paper, pharmaceuticals, energy, and beauty.

Of course, I am partial to the oxygen that they provide for us. In that spirit, today’s post will feature another superphotosynthesizer: the Cat Island Baldcypress located on the Cat Island National Wildlife Refuge in West Feliciana Parish, LA. This tree is the national champion of its species and also noted as the largest tree of any species east of the Sierra Nevada range.

It is located at the end of an easy walking trail (0.75 mile round-trip), but it only accessible for part of the year. Access to portions of the Cat Island NWR is prevented by levels of the Mississippi River since at least a couple of low bridges must be traversed to get you from the main road to the trailhead. If the river stage at Baton Rouge is greater than 20 feet, which is usually between February and June, there is no vehicle access to the trail. I was able to make a trip there in early February just before the river restricted access. It’s not quite clear whether the base of the tree itself is submerged at any point during the spring flooding because there is a really nice decking just before the tree at the end of the trail. As of today, the river stage at Baton Rouge is 27.8 feet, so it may still be another month before access is regained.

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The tree is impressive. At 96 feet it is taller than all the other trees around, but it’s certainly not the tallest tree east of the Sierra Nevada. However, its girth is undeniably impressive. It has the characteristic buttressed-base of all baldcypress trees, which measures 17 feet in diameter and 56 feet in circumference.  It has knees as tall as me. Well, for those of you who know me in real life maybe that’s not so impressive, but for a random root outgrowth that is still significant.

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This brings me to one of the real secrets of the swamp- cypress knees. These strange growths at the base of cypress trees have been puzzling botanists and plant biologists for centuries since Francois Andre Michaux wrote in 1819, “No cause can be assigned for their existence.” Many people have had theories as to how they contribute to cypress biology- increased aeration capability for growing in inundated swamps, methane (swamp gas) emission conduits, vegetative reproduction, mechanical support, nutrient acquisition, and carbohydrate storage. None of these hypotheses have really held up to analysis and the biological function* of these root outgrowths are still fascinating plant biologists today.

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This is just one local fascinating plant example. Check out the links below for more information about Fascination of Plants Day or follow #FOPD on social media.

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Johnna

*These expendable appendages are painted and carved for folk art projects. They are also fairly proficient at disemboweling lawnmowers of homeowners with cypress trees in their yards and capsizing careless motorboat operators in the swamps. Perhaps this is a plant defense mechanism ahead of its time.

References and Links:

http://www.plantday.org/

http://fascinationofplantsday.org/home.htm

http://blog.aspb.org/fascination-of-plants-day/about-fascination-of-plants-day/

http://blog.aspb.org/fascination-of-plants-day/

http://www.fws.gov/refuges/profiles/index.cfm?id=43697

http://www.fws.gov/refuge/Cat_Island/visit/plan_your_visit.html

http://www.monumentaltrees.com/en/trees/baldcypress/deep_south/

http://www.na.fs.fed.us/pubs/silvics_manual/Volume_1/taxodium/distichum.htm

http://en.wikipedia.org/wiki/Cypress_knee

http://www.venerabletrees.org/good-knees-said-baldcypress/

http://arnoldia.arboretum.harvard.edu/pdf/articles/2000-60-4-cypress-knees-an-enduring-enigma.pdf

On becoming a tree…

“As long as you keep getting born, it’s all right to die sometimes”

Orson Scott Card, The Speaker for the Dead.

I’ve written many times about the differences between autotrophs and heterotrophs on this blog. Loyal readers will know I have a hard-line stance that humans fall decidedly into the heterotroph camp. Nevertheless, some art projects blur the lines between person and plant. So I was more than a little intrigued when a link for the Bios Urn came across my Facebook feed.

BiosUrn

The product offers an alternative to the traditional cemetery as your eternal destination. It’s a special biodegradable urn in which your ashes (or a loved one’s or a pet’s ashes) can be placed along with a tree seed. The whole thing is planted in the ground at a cemetery or other special location. The recycled carbon atoms of your body become the growth medium for a tree that will grow and live on after your death.

biosurn2

It’s beautiful. I get it and as someone who often quotes the Lorax, I’m all for any excuse to plant trees. But honestly, the first thing it made me think of was my all-time favorite book The Speaker for the Dead by Orson Scott Card.* Within the world of this book, humans live on a colony planet that happens to have another species of sentient beings called the Pequeninos. These organisms spend the majority of their life cycle as mammal-like beings, but can pass on into a third life as a tree provided they have been vivisected. It’s pretty gruesome and obviously humans don’t work this way, so cultural misunderstandings ensue.

However, because I’m a stickler for scientific accuracy when it comes to plant science (Hey, someone’s gotta be.), I have one problem with the overly simplistic marketing scheme of the Bios Urn. You don’t actually become the tree. For those of you saying, “I know, I know I won’t be a tree, but in the circle of life my molecules will become part of this tree.” I’ll still be over here at my blog shaking my head, “No, that’s not really how that works.” Here’s a reminder of the photosynthetic equation:

6 CO2 + 6 H2O (+ light) → C6H12O6 + 6 O2

Plants accumulate carbon and mass from atmospheric CO2, not carbon ash or even organic carbon compounds in the soil. The truth is that if you planted your ashes with your tree seed, your carbon would still remain locked in the soil for many years until eventually it is metabolized by microorganisms in the soil and released as CO2 as part of their respiration. This is not a very quick way to turn over your carbon molecules, and your molecules have millennia before they ever become a part of any tree. If you truly wanted your carbon molecules to incorporate into some kind of plant matter, then you need to find a way to carbonate your deceased body. Human carbonated essence could be stored in canisters and then used to supply CO2 to your plant of choice. You could be part of that camellia bush in your front yard, your favorite LSU Oak tree, the General Sherman etc. Scientifically accurate, but good luck marketing that compared to cremation.**

All of this highlights a common misconception about photosynthesis- it’s hard to comprehend how mass can accumulate into living things from air. Our gut tells us mass must come from something more substantial. We memorize the photosynthetic equation in elementary school, but few of us grasp its consequences and really believe it.

“This is how humans are: We question all our beliefs, except for the ones that we really believe in, and those we never think to question.”

Orson Scott Card, The Speaker for the Dead

So, when you die, ask someone to plant a tree or something in your memory. Do it for someone else you’d like to remember, but ashes not really required. Or buy a BiosUrn or put the ashes in a degradable coir starter pot from your local garden center, but you’ll probably want to supplement them with some form of NPK fertilizer. It will help the seed more than your carbon atoms.

Johnna

*It’s a sequel to Ender’s Game for those of you that may not be SciFi freaks.

**Although, in-home soda fountains are a thing now, so if there is a way to carbonate deceased relatives and store them in the handy canisters… well, you get the idea.

Links and References:

https://urnabios.com/

http://en.wikipedia.org/wiki/Speaker_for_the_Dead

The Dangerous Double Life of a Distinctive Diazotroph

For many people around the world, tonight is one of the most anticipated nights of the year. In that spirit, here’s some new science, not under the sun, but under the moonlight and starlight. New research from Wegener, Nagarajan and Pakrasi* describe something new about the Photosystem II D1 protein, an unexpected source that photosynthesis researchers had long written off as conquered or fully explained.

Why would we care about photosynthesis at night anyway? It all comes down to the distinctive lifestyle of the cyanobacterium Cyanothece, which belongs to an interesting class called unicellular diazotrophs (word of the day). Like all cyanobacteria, they perform oxygenic photosynthesis but they have the bonus biochemical ability of nitrogen-fixation.

Nitrogen-fixers are capable of pulling nitrogen gas (N2) out of the air and turning it into ammonia which the cells can use as a nitrogen source for important molecules like protein and DNA. Other microbes can perform nitrogen-fixation, and you may remember them as the root nodule symbionts of legumes. If you’re not a nitrogen-fixer, you have to rely on ammonia or other nitrate compounds present in the soil, sea or your diet (depending on what kind of organism you are) to make the required nitrogenous biomolecules. Since the Earth’s atmosphere is 78% N2, you don’t have to be great at math to figure out that acquiring the ability to tap into the atmospheric nitrogen source advances your species in the game of life a considerable number of squares.

What does this have to do with photosynthesis? Why don’t more plants and cyanobacteria get in on this nitrogen-fixation biochemistry? There’s a critical fatal flaw in the photosynthesis/nitrogen-fixation biochemical tango. Nitrogenase, the enzyme responsible for the nitrogen-fixation reaction is hopelessly and irreversibly killed by oxygen. Oxygen destroys the protein enzyme that’s already been made and tells the genome not to even bother wasting energy trying to make it new. If you’ve been paying attention to the blog, oxygenic photosynthesizers like cyanobacteria and plants make oxygen via their PSII enzyme every time light shines on them. So for nonphotosynthetic soil bacteria and other microbes, it’s not a big deal to avoid oxygen and go anaerobic to fix nitrogen. Cyanobacteria, however, must lead dangerous double lives to combine these two opposing biochemical processes.

Anabeana spherica via Wikimedia Commons The more round cell in the center of the string is the nitrogen-fixing heterocyst.

Some diazotrophic cyanobacteria solve this problem by separating these two processes in space. Species like Anabeana can go through a special type of development where the cells divide themselves, but incompletely to form a connected network like beads on a string. Every tenth cell (heterocyst) gets an extra layer of cell wall, destroys its photosynthetic machinery, and commits itself to a life of nitrogen-fixation. These cells share their fixed nitrogen compounds with their neighbors, which in turn share their fixed-carbon from photosynthesis. This is a fascinating process still hasn’t given up all of its secrets and remains an active area of research.

Cyanothece 51142 by Michelle Liberton, Pakrasi lab

Cyanothece 51142 by Michelle Liberton, Pakrasi lab

Cyanothece, on the other hand, is a more ruggedly individualistic species that manages to perform both oxygenic photosynthesis and nitrogen-fixation within a single cell. It accomplishes this through a carefully controlled circadian rhythm. During the day, oxygenic photosynthesis occurs. During the night, nitrogen-fixation occurs. It sounds so simple, yet this elegance is far from easy. This is a true circadian process, in that, while some cues are definitely derived from light signals, the cells also have a strong internal clock that keeps the time of day and controls what biochemical machinery is active. Thus, near the hour of dawn and dusk, the cells are actively preparing for the metabolism to come. Also, if you were to train a culture of these cells under a certain day/night cycle for several days then switch them to continuous light, they would still maintain their circadian biochemical cycle for several days after the switch.

One issue that has puzzled researchers for some time is that the photosynthetic machinery, like PSII, is actively shut down at night. It’s not just that it’s dark, so there won’t be any photosynthetic oxygen production. Apparently, that’s not good enough. The cells actively shut it down. When researchers take culture samples of these cells during their dark period and shine light on them to check photosynthetic capability, there is no signal. Sure, there’s probably little chance any significant photosynthesis is occurring at night, but Cyanothece isn’t taking any chances. For these cells, no moonlight, floodlights from passing ships, comets, or even the blessed Eastern Star is going to interfere with their nocturnal nitrogen fixation.

Shutting down photosynthesis is no small feat. Again, if you’ve been paying attention to the blog, you will note that I’ve ranted on numerous occasions about how complex PSII is and how difficult it is to assemble  and reassemble from its individual parts. As far as energetics are concerned, it would be a losing battle for Cyanothece to completely disassemble its PSII at dusk only to resynthesize it again the next morning. I don’t care how hard-up it is for a nitrogen source. As it turns out, Cyanothece and other unicellular diazotrophic cyanobacteria solve this problem in a more graceful way, for which Wegener et al have provided new experimental evidence.

Cyanothece, like all other oxygenic photosynthesizers, contains multiple copies of the psbA gene encoding the D1 protein, which is a core subunit of PSII and critical for function. Since the advent of the genomic era, the genomes of numerous photosynthetic organisms have been sequenced revealing these multiple psbA genes, most of which have little or no protein sequence differences. These subtle changes have been linked to cells’ ability to fine-tune photosynthesis under certain conditions. However, Cyanothece and its cousins have a psbA gene copy that is particularly different- psbA4. If one were to take all of the site-directed mutants that photosynthesis researchers made to sort out PSII function over the last few decades since molecular biology techniques were available and threw them altogether into a single mutant gene, you would get psbA4. If PSII contained the D1 protein encoded by psbA4, there would be no C-terminal processing and no active site for water-splitting and oxygen production.

Why would any self-respecting photosynthetic organism retain such an utterly non-functional PSII subunit? The answer is because it does serve a critical function in the daily cycle of Cyanothece, just not during the day. The D1 protein encoded by the psbA4 gene, called a sentinel D1 protein (sD1), is made only for the night, when it does the only thing it still can do- fit right in the center of the PSII complex and prevent PSII function of any kind. There’s no chance of any oxygen production while sentinel D1 is on duty, but the cells can maintain most of the other PSII components in a stable complex (meaning they don’t have to be degraded and made fresh every morning). Then, Cyanothece can turn photosynthesis back on in the morning by replacing a single protein in its PSII complexes. The report by Wegener et al gives the first biochemical characterization of PSII complexes containing a sentinel D1 protein, providing evidence that this strategy works for controlling PSII oxygen production.

sentinel

Performing oxygenic photosynthesis and nitrogen-fixation within the same cell is biochemically problematic, but the sentinel D1 protein appears to be the secret weapon for this dangerous double life. Through this strategy oxygenic photosynthesis and nitrogen fixation are “Always together, eternally apart.”** Many questions remain regarding the regulation of the transition from functional D1 to sentinel D1 at dusk and the reverse replacement at dawn. There are still outstanding questions regarding the D1 turnover event for any PSII in any photosynthetic organism, so it’s not at all clear what parts of this process Cyanothece uses or whether new factors are involved. Obviously, there must also be some sophisticated regulation to prevent the synthesis of sentinel D1 during the day.

While this work focuses on an organism you’ve never heard of, it has some interesting biotech implications for the future. As I mentioned, being able to both fix CO2 through photosynthesis and N2 through nitrogenase puts you at a significant metabolic advantage. And no, I don’t mean you. Remember, we’ve been through this- people are not photosynthetic. It would be great if one day we could engineer certain crop plants to combine these traits. Legumes already have this trick covered through symbiosis, but many other staple crops require tons of nitrogen fertilizer. If researchers could unlock the secrets of Cyanothece’s double life and translate it to plants, then it may be possible to engineer versions of crop plants that don’t require so much nitrogen fertilizer. Thus, one night in the future, engineered crop plants may be fixing nitrogen thanks to the addition of a variant gene they already had.

Johnna

*I know I’ve posted frequently about Pakrasi lab (my thesis lab) research, but this topic was just developing as I was leaving the lab and it’s too cool to pass up.

**Bonus points to you if you get the movie reference.

References and Links:

http://www.jbc.org/content/early/2014/12/18/jbc.M114.604124.full.pdf+html?sid=8f38f7c6-96c1-4085-bbb0-efc6ca425624

Binding P’s and Q’s, Minding T’s and I’s

When it comes to nailing down the location of P and Q in plant Photosystem II, you have to be careful how you cross your t’s and dot your i’s.

A longstanding question in the area of Photosystem II research involves the complement of proteins on the lumenal side of the enzyme in plants vs. cyanobacteria. This region of the complex serves to split water into molecular oxygen- a seemingly conserved reaction in all oxygenic photosynthetic organisms. However, it has long been known that the extrinsic proteins associated with the lumenal face of the complex differ significantly between plants and cyanobacteria.

Differences in the lumenal extrinsic proteins, plants vs. cyanobacteria

Differences in the lumenal extrinsic proteins, plants vs. cyanobacteria

Studies from various disciplines in recent years (structural, mutants, proteomic) have layered on more questions. Biochemical work on plants indicates there are three extrinsic proteins- PsbO, PsbP and PsbQ. Biochemical analysis and structural studies of cyanobacteria have shown that their PSII complexes contain PsbO, PsbU and PsbV. Other proteomic analysis and mutant studies have shown that cyanobacteria also contain homologues of PsbP and PsbQ (aka CyanoP and CyanoQ, respectively). Sure, this accumulation of data sounds like alphabet soup to those outside of our field, but it also leaves photosynthesis researchers wondering how appropriate it is to use structural information from cyanobacteria to infer anything about PSII structure in plants.

For all the knowledge we’ve gained, we’ve been comparing green apples to blue-green oranges. New research from the Bricker lab has used chemical crosslinking and mass spectrometry to gain more information on the organization of extrinsic proteins in plant PSII- directly from plant material. I’ve written about these techniques before in another paper addressing a similar problem from the cyanobacterial extrinsic protein vantage point. In a publication available electronically this week, Mummadisetti et al provide new information on the arrangement of the PsbP and PsbQ proteins in higher plant PSII. This work goes beyond what either of the individual protein crystal structures (not in the context of the PSII complex) could tell us. Distance constraints from the crosslinking data were used to guide modeling studies to fill in gaps in the solution structure of PsbP as well as identify interaction sites with PSII membrane components and another extrinsic protein, PsbQ. Altogether this gives us a more complete picture of an important enzyme.

In addition to the satisfaction that comes with publishing this great work in a top journal, the authors have also been featured in a research highlight by the university. Since I like to take things a step further on this blog, this post will feature the behind the scenes story of how this project came to be a publication worthy of a press release- especially with regard to how the story is told with imagery.

As is typical of any press release, an image is used to capture the essence of the research. In the featured image, we see Manju Mummadisetti without lab coat and gloves, holding her PSII membranes proudly aloft the pristine ice bucket next to a carefully positioned bag of spinach leaves that have yet to meet their demise in the Waring blender. I get it. In photosynthesis research labs we always have a tube or bubbling flask of something green-ish that easily fits the stereotype non-scientists have of what scientists must do all day long. Every. Day.

Credit: Louisiana State University

Credit: Louisiana State University

Long time readers of this blog will realize that in this image Manju is breaking the first rule of biochemistry. Fast. And. Cold. No self-respecting biochemist would gaze longingly at their biochemical sample that wasn’t on ice or in the cold room. Moreover, photosynthesis researchers opt for darkness or dim light for their preparations in order to keep activity low and avoid damage. I can say unequivocally that Manju knows and obeys all of the rules of biochemistry. This sample was only for practice or for show. A more true picture would look like this.

What real research looks like

What real research looks like

Notice the lab coat and gloves. Samples are kept in the ice bucket. For all you know, there’s nothing in there at all green or otherwise.*

Manju spent considerably more time gazing at data on her computer screen than she ever did her green samples. In the picture below, she is analyzing mass spec data and evaluating the validity of calls made by the software. p > 0.005 need not apply for her results, but anything better is painstakingly recorded on a brown paper towel.

005

But really, Manju’s research is more appropriately captured in other images like this one.

It's harder than you think

It’s harder than you think

It may not make for click bait, but carefully filling out FedEx shipping forms is an essential part of her research. After Manju prepares her samples, they must be shipped overnight on dry ice (Fast. And. Cold.) to collaborators in Cincinnati for the mass spectroscopy analysis. These shipments are carefully planned so that someone is available to receive them and perform the analysis. This isn’t always easy over the summer when it is necessary to coordinate the travel schedules of half a dozen researchers in two different labs.

On one such occasion, forms and labels were not filled out appropriately. Not because Manju forgot to dot and i or cross a t, but because she did. Packages with dry ice require a special hazard label that must include all address information for both the sender and recipient in a very small area. We never knew how critical it was to avoid crossing that dotted line of the diamond.**

Notice how the last 'ti' in Manju's name infringes into the label

Notice how the last ‘ti’ in Manju’s name crosses over the dotted line and into the hazard label. Such a distraction could interfere with proper handling of this hazardous substance.

IMG_0038 (2)

Really FedEx? Her name is 20 characters long! Plus, the all caps just makes it seem like they’re yelling. It’s that serious.

A diligent FedEx employee at the Baton Rouge office rejected the shipment and sent it back to the lab at LSU the next day. I know rules are rules, but really this is on the verge of Gas Station Manager Syndrome. The samples were fine and promptly placed back in the freezer. A flurry of NSFW text messages about the situation were exchanged among people still on vacation. A new shipment date was coordinated and new forms were completed. It went away without a hitch and was promptly turned into data.

A new lesson was learned that day- Thou shalt not write within the dotted line of the hazard label. It’s an extension of a long-standing research rule- Obey arbitrary formatting and paperwork requests from people that control what you need.

 

Johnna

*Full disclosure- there was NO sample in that ice bucket. No one in the lab had any membranes prepped that day and real biochemists don’t pull good samples out of the freezer for a photo op.

**It’s like crossing the streams in Ghostbusters apparently. It would be bad.

References and Links:

http://www.pnas.org/content/early/2014/10/24/1415165111.short

http://www.lsu.edu/ur/ocur/lsunews/MediaCenter/News/2014/10/item73226.html

Corpse Flower: The Living Dead

Corpse Flower Credit: U.S. Botanic Garden via Wikipedia

Today’s plant costume is an odiferous disguise instead of a visual one. Its common name is also appropriate for the Halloween season- The Corpse Flower. It only pretends to be dead by giving off a rank odor of rotting flesh when it blooms. Again the reason is pollination. This horrible smell to us calls to every beetle and fly around that supper’s on. While they root around in the tight dark spaces of the bloom trying to find a decent place to feed and lay their eggs, they become covered in pollen. These pollen-covered insects then fly off to another bloom to pollinate another plant.

This species, Amorphophallus titanum*, is also a superphotosynthesizer in the plant world. As you may have noticed from the pictures and videos, the blooms can be as large as 10 feet tall. This makes the corpse flower the world’s largest inflorescence. Notice I didn’t say flower. Ah, botanical anatomy semantics! The images may look like a giant flower with burgundy petals surrounding a central stigma on steroids. Not so. The ‘petal’ portion of the flower is actually a bract structure called a spathe (plant biology word of the day). The tall central feature is called a spadix (bonus plant biology word of the day), and it is this structure on which the true flowers of the plant (separate male and female flowers) are arranged. The entirety of this plant reproductive structure is the inflorescence and there isn’t a bigger one in the plant world. The world’s record for a corpse flower bloom is nearly 11 feet tall. After flowering, the plant then makes the world’s largest leaf structure. It may look a tree in its own right, but developmentally, it’s just a compound leaf.

Johnna

* Grossly translated as giant misshapen penis. Yeah. Well, you’ve seen the pictures. Stay classy readers!

References and Links:

http://en.wikipedia.org/wiki/Amorphophallus_titanum

http://www.usbg.gov/return-titan

http://news.nationalgeographic.com/news/2013/07/130715-corpse-flower-bloom-botany-science/

http://bioscigreenhouse.osu.edu/titan-arum-faqs

http://titanarum.uconn.edu/199500115.html

http://www.fosters.com/apps/pbcs.dll/article?AID=/20100924/GJNEWS02/709249916

http://www.missouribotanicalgarden.org/gardens-gardening/our-garden/notable-plant-collections/titan-arum.aspx

http://www.news.wisc.edu/titanarum2005/facts.html

#WhyPlants

The American Society of Plant Biologists is asking plant scientists out there- ‘Why Plants?’ Your response via their social media outlets could earn you free registration for their 2015 annual meeting.*

I’ve written before generally about why I bother being a scientist. But why plants in particular?
I have snarky answers. Arabidopsis smells better than E. coli. Chlorophyll and plant cell lysates are easier to remove from lab coats than blood. At least, there’s less therapy involved from the psychological effects of grinding up plants as opposed to the same treatment of other model organisms that can stare back at you. Plants are generally easier to wrangle than fruit flies and other more mobile systems. Plants even come with a ready-made system for long term storage.** From a purely technical standpoint, plants are an advantageous system to work with.

Of course, it’s not all roses with plant biology. Plants can take a long time to grow up for experiments and, depending on the system, you may need the patience of Job to work with them without going crazy. Since I care about the photosynthetic apparatus of plants, I think I spend just as much time with my samples in the dark. Who wouldn’t want to spend their days hunched over a fluorometer in a dark closet?

I also have serious answers, but first, a confession. I consider myself a biochemist-who-works-on-plants rather than a legitimate plant-biologist (although I play one on this blog). As far as biochemistry goes, plants are the most complicated organisms on the planet. Maybe I’m just a glutton for punishment, but if I’m going to work on one puzzle in my scientific career, I’m going to pick the one with the most pieces, the one that will give the most beautiful picture in the end. In my opinion, that subject is plants.

Photosynthesis, in particular, is more fascinating than the equation we all had to learn in elementary school. Light and water are universal positive symbols across all human cultures. The foundation for this is our connection with plants. Plants convert these substrates into the chemical energy used by the rest of life on earth. Sure, my body needs water in its own right and sunlight does elicit some metabolic responses from my human cells, but plants are literally our energetic connection with the cosmos.

For those of you who’ve always wondered, “Why does she work on that?” I hope this post has answered some of your lingering questions. For the rest of you plant biologists out there- what’s your answer to #WhyPlants?

Johnna

*It’s in Minneapolis in June, so I have my own selfish reasons for trying to win a reason to escape LA in June.
** Give yourself bonus points if you knew I was talking about seeds.

Game Day Botanicals

This Saturday marks a special holiday for Louisiana. It is the day that LSU football returns to Tiger Stadium. Sure, devout members of the Tiger Nation traveled to Houston last weekend for the first game of the season, and the rest of us watched intently as our team finally showed up near the end of the third quarter. But this weekend the Tigers come home. We LSU fans feel very strongly about our home turf. I’m sure many of my friends and family reading this already know what I mean. LSU opponents understand as well. For those of you still wondering what it’s all about, I highly recommend the video below. Go ahead and watch it. I’ll wait.

I know you only come to this blog for the plant science. Well, I’m getting to that. I understand you may have been hypnotized by the eye of the tiger, bedazzled by the stadium lights, and flinched at the tackle shots. However, if you were paying close attention, you should have noticed the foundation of Death Valley- the green field itself. Today’s edition of holiday plants will explore the turfgrass of Tiger Stadium. It is as critical to our football traditions as it is to our winning game plans.

For Tiger Stadium, there is always excessive Celebration on the field. I’m not talking penalties though. The botanical MVP is named Celebration turfgrass, a Bermuda grass variety of Cyodon dactylon. This turfgrass has numerous characteristics that make it ideal for stadium coverage. It recovers well from damage, thrives in hot weather, withstands drought conditions and keeps its green color longer than other turfgrass options. It also establishes itself quickly, which is a necessity for Tiger Stadium since the turf must be completely replaced every year because of the damage done to the field during the Memorial Day weekend Bayou Country Superfest concert.* It’s not so much the drunken revelers in cowboy boots as it is the heavy stage, sound and light equipment in the middle of it all.

Having a fresh new carpet of Celebration turfgrass takes more work than you might imagine. The LSU Athletics Facilities and Grounds crew gets to work in June making sure the newly lain sod takes to its new home. Once football season is underway, the field must be presentation ready on a weekly basis. Check out the video below where Eric Fasbender describes the upkeep for the Celebration field at Tiger Stadium.

Another important feature of Celebration grass is its shade tolerance. This trait is critical for stadium grasses because of the shadows cast by the towering arena structures surrounding the field. Not every field boasts a mobile field surface that can be moved out into full sun.** Since Tiger Stadium boasts a new expansion of the south endzone to accommodate seating for more than 102,000 fans, the shadows cast onto the field must be taken seriously. I wonder if the Athletic Department would give me a grant to study the photosynthetic efficiency of the grass over the course of football season? I think they must have about the same amount of money as the NSF. Now, that gives me a new project idea for whenever those PhotosynQ guys send me that handheld fluorometer that collects data onto my smartphone.

The grass may generally be taken for granted by LSU fans, but it does have a special place in the overall mystique of Death Valley. A few years ago for April Fool’s Day, the LSU athletics department posted an article announcing that the surface would be changed to a purple synthetic turf material. This was met with a humorous uproar of righteous indignation at such a defamation of our beloved sports temple. Until of course, people looked at a calendar and realized it was just a joke. Plus, Les Miles eats blades of grass off of the field. Apparently Celebration turf tastes great.

The field can also serve as an autotrophic teammate. Our head coach isn’t the only one with magic tricks up his sleeves. The grounds crew knows just how to prep the field to create the conditions complementary to the type of game that will be most favorable for the purple and gold. They can make the field slow for a game that favors rushing or fast to highlight the speed of our wide receivers and defenders. Yes, they can do that. No, they will not tell you how. Those are secrets that just add to the difficulty of being an opponent in Death Valley.

So, as you are celebrating game day this Saturday, have some respect for the Celebration on the field.

 

Johnna

*Superhero PhD has already given her opinion on this concert.

**LSU Althletic Department, please don’t get any ideas. I really don’t want to give up any more parking on campus, which may affect my hike to work.

References and Links:

http://en.wikipedia.org/wiki/Tiger_Stadium_%28LSU%29

http://www.nola.com/entertainment/baton-rouge/index.ssf/2013/05/lsus_tiger_stadium_bayou_count.html

http://www.wafb.com/story/15450861/lsus-special-celebration

http://www.pikecreekturf.com/celebration.html

http://en.wikipedia.org/wiki/Sod

http://en.wikipedia.org/wiki/Cynodon_dactylon

http://www.celebrationturf.com/

http://www.sodsolutions.com/research

http://www.lsusports.net/ViewArticle.dbml?ATCLID=204919830

http://nesn.com/2010/11/lsu-coach-les-miles-eats-grass-off-field-as-game-time-tradition/

http://louisianafb.com/blog/2013/03/21/the-grass-is-always-green-at-tiger-stadium/

http://www.lsuagcenter.com/en/lawn_garden/commercial_horticulture/turfgrass/athletic_fields/Sports+Field+Maintenance.htm