Here’s something you don’t see everyday: a university sending out a press release showing the potential benefits on crop yields of elevated atmospheric CO2 levels. – Anthony
Public release date: 9-Feb-2009
http://www.eurekalert.org/pub_releases/2009-02/uoia-hcb020609.php
Contact: Diana Yates
217-333-5802
University of Illinois at Urbana-Champaign
High CO2 boosts plant respiration, potentially affecting climate and crops
The leaves of soybeans grown at the elevated carbon dioxide (CO2) levels predicted for the year 2050 respire more than those grown under current atmospheric conditions, researchers report, a finding that will help fine-tune climate models and could point to increased crop yields as CO2 levels rise. The study, from researchers at the University of Illinois and the U.S. Dept. of Agriculture, appears this week in the Proceedings of the National Academy of Sciences. Plants draw CO2 from the atmosphere and make sugars through the process of photosynthesis. But they also release some CO2 during respiration as they use the sugars to generate energy for self-maintenance and growth. How elevated CO2 affects plant respiration will therefore influence future food supplies and the extent to which plants can capture CO2 from the air and store it as carbon in their tissues. While there is broad agreement that higher atmospheric CO2 levels stimulate photosynthesis in C3 plants, such as soybean, no such consensus exists on how rising CO2 levels will affect plant respiration.
IMAGE: Andrew Leakey and assistants at work in the Soy FACE facility at Illinois. Click here for more information.
“There’s been a great deal of controversy about how plant respiration responds to elevated CO2,” said U. of I. plant biology professor Andrew Leakey, who led the study. “Some summary studies suggest it will go down by 18 percent, some suggest it won’t change, and some suggest it will increase as much as 11 percent.” Understanding how the respiratory pathway responds when plants are grown at elevated CO2 is key to reducing this uncertainty, Leakey said.
His team used microarrays, a genomic tool that can detect changes in the activity of thousands of genes at a time, to learn which genes in the high CO2 plants were being switched on at higher or lower levels than those of the soybeans grown at current CO2 levels. Rather than assessing plants grown in chambers in a greenhouse, as most studies have done, Leakey’s team made use of the Soybean Free Air Concentration Enrichment (Soy FACE) facility at Illinois. This open-air research lab can expose a soybean field to a variety of atmospheric CO2 levels – without isolating the plants from other environmental influences, such as rainfall, sunlight and insects. Some of the plants were exposed to atmospheric CO2 levels of 550 parts per million (ppm), the level predicted for the year 2050 if current trends continue. These were compared to plants grown at ambient CO2 levels (380 ppm).
The results were striking. At least 90 different genes coding the majority of enzymes in the cascade of chemical reactions that govern respiration were switched on (expressed) at higher levels in the soybeans grown at high CO2 levels. This explained how the plants were able to use the increased supply of sugars from stimulated photosynthesis under high CO2 conditions to produce energy, Leakey said. The rate of respiration increased 37 percent at the elevated CO2 levels. The enhanced respiration is likely to support greater transport of sugars from leaves to other growing parts of the plant, including the seeds, Leakey said. “The expression of over 600 genes was altered by elevated CO2 in total, which will help us to understand how the response is regulated and also hopefully produce crops that will perform better in the future,” he said.
IMAGE: Illinois plant biology professor Andrew Leakey led a team that discovered that soybean leaves speed up their metabolism in response to rising CO2. Click here for more information.
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Maybe a bigger question is whether CO2 fertilizes the production of calcium carbonate in water. One of my big reasons for being a skeptic is that while it is true we are releasing eons worth of carbon fossilized as coal and petroleum. The actual rock sequences show us that most carbon is sequestered as limestone not fossil fuels.
Barry B. (08:31:12) :
Gary (05:59:30) :
Respiration in plants is not the same as with animals. In fact, it is just the opposite. Plants take in CO2 & release O2.
Plants take in CO2 and convert it into carbohydrate, proteins, and derivatives. We eat carbohydrates and proteins and convert it into tissue and excrement. Respiration in plants is almost identical to humans, done in mitochondria.
Ken Hall (06:04:26) : “If this is indeed the case and plants can switch on a gene that allows greater uptake of CO2 when the level is correct, then we should soon start to see a leveling off of the current atmospheric concentrations of CO2 shouldn’t we?”
Not necessarily.
Herbaceous plants primarily store carbon below ground. In order for it to remain there, the ground must be left undisturbed. With todays agricultural practices most of the ground is tilled which releases the carbon back into the atmosphere. Therefore, the increased uptake makes no difference.
REPLY: I’m a little unclear on your idea that tilling releases carbon back into the atmosphere. Can you elaborate? – Anthony
Carbon is “stored” in slowly degradable materials, collectively called soil “organic matter”. The soil organic matter of plowed soil is roughly 2-3%, whereas in no-till cultivation it is significantly greater 5-10%. Therefore, plowing the soil increases the biodegradation of OM and releases the C stored in the soil. However, soil OM can increase above that, and in fact is increasing (even in plowed soil) in response to modern higher yields. Note the usage of the word, herbaceous. This brief anaysis is not relavant to perennial species.
I’m a little unclear on your idea that tilling releases carbon back into the atmosphere. Can you elaborate? – Anthony
With all due respect Anthony, it is not my “idea”. It is a well established fact.
Carbon is stored in the soil via organic matter, which is approximately 57% carbon by weight. Under semi-aerobic and anaerobic conditions, the organic matter is converted by microbes into a more stable form called humus. When the soil is tilled, the tillage aerates the soil which in turn causes an increase in microbial action. This increased microbial action causes the organic matter to break down more rapidly, thus the carbon escapes as CO2 rather than being converted into humus.
Before being tilled, our natural prairie soils had a natural organic matter content of greater than 4%. Now, after decades of being plowed, we have lost between 30-50% of that organic matter.
REPLY: I wasn’t jumping on you, and I’m sorry if that is how you viewed it. I was just curious how the mechanism worked. I’m not soils specialist. – Anthony
Barry B. (08:31:12) :
Respiration is respiration. Plants use photosynthesis and the glucose created by that metabolic pathway for two things. One is to make cellulose to get bigger, the other is to provide fuel for making cellulose, growing roots, bark, flowers, in short, all the energy consuming things plants have to do. Respiration is more than breathing in and out with lungs.
Please reread the first paragraph of the press release.
The net effect of a plant’s photosynthesis is to take in CO2 and H2O and release O2, but that’s just because plants have to do more photosynthesis than respiration.
Barry B. (08:31:12) :
Gary (05:59:30) :
Respiration in plants is not the same as with animals. In fact, it is just the opposite. Plants take in CO2 & release O2.
Actually it is the same, plants take in CO2, water and sunlight and produce sugars and O2, this is photosynthesis. At the same time they also consume the sugars using O2 and produce CO2 and water (this is the only process occurring at night), this is respiration. This report refers to a higher level of CO2 resulting in a higher level of respiration, i.e. consumption of the sugars.
Tim Clark (09:45:17) :
Yes, you are correct. But Gary said that plants take in O2 and release CO2. That is not correct, it is just the opposite.
The Container Tree Nursery Manual, Volume 3: “Atmospheric Environment”, chapter 4, has more information on this. You can download chapters in pdf format at the following url: (available at other locations also)
http://www.rngr.net/Publications/ctnm
The Old Forester:
There have been numerous studies on the positive effect of increasing CO2 concentrations on forest growth. I remember taking Plant Physiology at U.C. Berkeley in the early 1960’s where we learned that atmospheric CO2 is suboptimal for plant growth. About twice the current concentration is about optimal. Since 1/3 of the nation is covered in forests, I think that delving into these studies would be fruitful, especially considering that dry wood is about 50% carbon by weight. My calculations show that managed forests in the Sierra/Cascade can capture about one ton of carbon per acre per year. If this material is put into long term storage, such as houses and furniture, and the residue turned into energy replacing some fossil fuels, the reduction in atmospheric carbon could be substantial. Of course we, as a nation, have chosen to let our forests needlessly go up in smoke and decay releasing the stored carbon back into the atmosphere. For a people who are so emotionally driven by “global warming” it seems a bit incongruous.
I’m amazed that WUWT would publish this and not explain it to the layman. This article is about latent genes that turn on to better handle CO2.
Respiration is thus:
C16H126O2 + 6O2 —> 6CO2 + 6H2O + energy
Hope that clears up
Re: Gary (05:59:30) :
You said: “Folks seem to be misreading this news release. The researcher was looking at plant respiration, not photosynthesis.”
Although their primary focus was photorespiration, they did address CO2-stimulated photosynthetic increases. From their paper:
“Elevated [CO2] stimulated photosynthesis of soybean by 20% in 2005 (Fig. S2A) and 22% in 2006 (Fig. 1A), which is consistent with the observed response in soybean (11) and C3 plants in general (12). This photosynthetic response is primarily biochemical, resulting from greater rates of carboxylation and reduced
rates of oxygenation catalyzed by Rubisco.”
http://www.pnas.org/content/early/2009/02/09/0810955106.full.pdf+html
I wish the authors had talked about soybean yield increases, but they didn’t (maybe that didn’t happen). So many of the studies of CO2 fertilization only address total dry matter changes. I would like to know if it produces more of the food portion, or just stems, roots and leaves.
Barry B – No, they do both.
Oh, but the salamanders are all dying due to “Global Warming”!!!!!!
But wait! The title of the article Salamanders “Completely Gone” Due to Global Warming ends with a question mark. In fact, in the article, the author of the study say quite clearly:
Yet at the end of the article you read this:
.
So if the study says it’s NOT Climate Change, why is that in the article? Why is GW even in the title? It’s the obligatory nod to the Evil Of Our Time!!!! This gets to be a game after a while.
PS. If you roll your eyes too far, can they get stuck in the back of your head?
I have NO idea how my 6 became 16..I seem to have fumble fingers today
My previous post should have read
Respiration is thus:
C6H126O2 + 6O2 —> 6CO2 + 6H2O + energy
Phil. (09:52:55) says:
Barry B. (08:31:12) :
Gary (05:59:30) :
Respiration in plants is not the same as with animals. In fact, it is just the opposite. Plants take in CO2 & release O2.
Actually it is the same, plants take in CO2, water and sunlight and produce sugars and O2, this is photosynthesis. At the same time they also consume the sugars using O2 and produce CO2 and water (this is the only process occurring at night), this is respiration.
This report refers to a higher level of CO2 resulting in a higher level of respiration, i.e. consumption of the sugars.
Can you provide a little explanation? How does higher levels of CO2 yield higher levels of respiration when CO2 does not seem to be an input to the chemical reaction? Also, wouldn’t the higher partial pressure of CO2 in the atmosphere tend to depress the reaction? (Of course, this is just pure speculation on my part.)
From Answer.com,
“C3 plants, accounting for more than 95% of earth’s plant species, use rubisco to make a three-carbon compound as the first stable product of carbon fixation. C3 plants flourish in cool, wet, and cloudy climates, where light levels may be low, because the metabolic pathway is more energy efficient, and if water is plentiful, the stomata can stay open and let in more carbon dioxide. However, carbon losses through photorespiration are high.
C4 plants possess biochemical and anatomical mechanisms to raise the intercellular carbon dioxide concentration at the site of fixation, and this reduces, and sometimes eliminates, carbon losses by photorespiration. C4 plants, which inhabit hot, dry evironments, have very high water-use efficiency, so that there can be up to twice as much photosynthesis per gram of water as in C3 plants, but C4 metabolism is inefficient in shady or cool environments. Less than 1% of earth’s plant species can be classified as C4.”
hmmmm, which species will grow better during the next ice age?
Gee, and all the time I thought those giant tent farms down in the Fresno/Visalia area were just big barns to hold square dancing in; and the gas they were pouring in there was Nitrous oxide to liven the people up.
You have to have a university study to figure out that plants need CO2 to grow?
They knew over 20 years ago, maybe 40, that about 20% of the entire world food production cannot be explained, unless you take into account the fact the there’s an extra 100 ppm of CO2 in the atmosphere. So which 1.2 billion people should we eliminate so we can go back to where we were?
I bet if they got Michael Man to look into some Carboniferous age proxies, they would find that while they had all that CO2 in the air, that plants grew like crazy, and laid down all that lovely fossil fuel for us to find.
James P (04:08:00) : “I take your general point, but IIRC, about a third of the world goes to bed hungry.”
According to the UN Food and Agriculture organization, the proportion of world population “undernourished” was about 16% in 1990-92, 14% in 1995-96, and 13% in 2003-05. The absolute number of undernourished people fell for decades, until recent years when food prices went up. In some parts of the world a third or more of the people are considered undernourished.
ftp://ftp.fao.org/docrep/fao/011/i0291e/i0291e00.pdf
Phil. (09:52:55) says:
This is as I understand it and has been confirmed by Google, and commenters here.
Can you provide a little explanation? How does higher levels of CO2 yield higher levels of respiration when CO2 does not seem to be an input to the chemical reaction? Also, wouldn’t the higher partial pressure of CO2 in the atmosphere tend to depress the reaction? (Of course, this is just pure speculation on my part.)
(Arrgh … badly screwed up first attempt.)
“Folks seem to be misreading this news release. The researcher was looking at plant respiration, not photosynthesis. Respiration in plants is essentially the same as in animals: it uses O2 and releases CO2. The chemical pathways may be somewhat different, but the final result is the same – release of chemical energy for cell-building processes and release of CO2. ”
Hey Gary,
Your Cell-building sequesters carbon as celulose (C6H12O6)n. That happens at an accelerated rate, thus accelerated absorbsion of atmospheric CO2.
If you’re trying to say otherwise then, you’re wrong, thats all.
This surely is old news???
Carbon Dioxide In Greenhouses
Publication Date: 12/02
Order#: 00-077
Last Reviewed: 05/03
History: replaces OMAF Factsheet Carbon Dioxide in Greenhouses, Order No. 94-055
Written by: T.J Blom; W.A. Straver; F.J. Ingratta; Shalin Khosla – OMAF; Wayne Brown – OMAF
and species dependant
1997: Grotenhuis T; Reuveni J; Bugbee B
Super-optimal CO2 reduces wheat yield in growth chamber and greenhouse environments.
Advances in space research : the official journal of the Committee on Space Research (COSPAR) 1997;20(10):1901-4.
Seven growth chamber trials (six replicate trials using 0.035, 0.12, and 0.25% CO2 in air and one trial using 0.12, 0.80, and 2.0% CO2 in air) and three replicate greenhouse trials (0.035, 0.10, 0.18, 0.26, 0.50, and 1.0% CO2 in air) compare the effects of super-optimal CO2 on the seed yield, harvest index, and vegetative growth rate of wheat (Triticum aestivum L. cvs. USU-Apogee and Veery-10). Plants in the growth chamber trials were grown hydroponically under fluorescent lamps, while the greenhouse trials were grown under sunlight and high pressure sodium lamps and in soilless media. Plants in the greenhouse trials responded similarly to those in the growth chamber trials; maximum yields occurred near 0.10 and 0.12% CO2 and decreased significantly thereafter. This research indicates that the toxic effects of elevated CO2 are not specific to only one environment and has important implications for the design of bio-regenerative life support systems in space, and for the future of terrestrial agriculture.
And not always good:
In research to be presented at the annual meeting of the American Society of Plant Biologists in Chicago (July 7-11, 2007)
Many plants have inherent enzyme-based defenses that are released during insect attack. This study found that when soybeans (Glycine max) were exposed to elevated amounts of CO2 the plants became more susceptible to attack by Japanese beetles (Popillia japonica). Furthermore, as these beetles consumed the weakened soybeans, the insects invasive abilities were intensified.
Mike
pat (22:21:03) :
“Wow. We are almost back to 7th Grade Science. Wonderful. Shouldn’t this be classified?”
Not surprising. GW´rs ignore 3rd degree science. They just ignore the water cycle: They say a warmer climate means drier lands..and it is just the other way.
Talk about a Geeks blog -now we’re debating weeds.
“Terry Ward (01:41:28) :
We get some wild marijuana in the fields here and there. The cows eat the buds and leaves, but leave the stems.”
Ummmmm….is any of that beef for sale?
JimB
Barry B. (09:50:59) :
Before being tilled, our natural prairie soils had a natural organic matter content of greater than 4%. Now, after decades of being plowed, we have lost between 30-50% of that organic matter.
I must add, as a farmer who switched from tilled to no-tilled practice in intensive farming 11 years ago, that recovering the loss of organic matter/humus is reversible and rather fast, 4-8 years (depends on the soil) because of a much greater (micro)biological life and life diversity in non-tilled fields.
Now I think this kid is a real scientist. Thank you for the article; there’s still hope yet.