# Atmospheric chnages on plants



## John Paul Sanborn (Jul 20, 2009)

Biomass of Tomato Seedlings Exposed to an Allelopathic Phenolic Acid and Enriched Atmospheric Carbon Dioxide 

S. R. Shafer1 Contact Information, U. Blum1, S. J. Horton1 and D. L. Hesterberg1
(1) USDA-ARS Air Quality Program, Dept. of Plant Pathology Dept. of Plant Pathology, Dept. of Soil Science, North Carolina State University, Raleigh, NC 27695, USA

Abstract Increased atmospheric CO2 can affect plant growth, so competition among plants may be influenced. Allelopathy is one mechanism involved in plant competition. Experiments were conducted in a controlled-environment chamber to determine if the concentration of atmospheric CO2 altered the dose-response relationship between an allelopathic phenolic acid and tomato seedling biomass. Seeds of Lycopersicon lycopersicum were planted in quartz sand in styrofoam cups and allowed to germinate and grow for 15–17 days. During the next 14 days, seedlings were watered twice daily with nutrient solution amended with p-coumaric acid (4-hydroxycinnamic acid, HOC6H4CH = CHCO2H; ranging 0–0.85 mg mL-1; 5 concentrations in each experiment) and exposed 24 hr day-1 in continuous-stirred tank reactors (CSTRs) to ambient air (335–375 ppm CO2) or ambient air to which 350 ppm CO2 was added (i.e., approximately twice-ambient CO2; two CSTRs per CO2 concentration in each experiment). Dose-response data relating p-coumaric acid concentration and shoot, root, and total biomass were fit to a flexible decay function. In all three experiments, twice-ambient CO2 significantly increased the y-intercept for the dose-response model for the p-coumaric acid effect on shoot biomass by 25–50% but had negligible effects on other aspects of the models. Results suggest that if CO2 affects plant competition, mechanisms involving allelopathic phenolic acids may not be involved.

http://www.springerlink.com/content/t08r3w1383402618/


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## Urban Forester (Jul 20, 2009)

I would love to see the same test done on an environmentally sensitive tree (i.e. White Birch/Japanese Maple) and on a environmentally vigorous tree (i.e. Katsura/Ginkgo). Which would produce more/less secondary metabolites? Does the production of secondary metabolites create(?) a manipulated environment? Interesting stuff...


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## John Paul Sanborn (Jul 20, 2009)

Urban Forester said:


> a manipulated environment? Interesting stuff...



They have shown that higher CO2 makes poison ivey more vigorous and produces more urushiol.

This is an updated version, i first read about it over a year ago.



> Research Project: Crop and Weed Responses to Increasing Atmospheric Carbon Dioxide
> 
> Location: Crop Systems & Global Change
> 
> ...




Here is a search from that site for CO2 maple

http://pubsearch.arsnet.usda.gov/se...frontend&proxystylesheet=ars_frontend&lr=&oe=


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## Ed Roland (Jul 21, 2009)

"Ambient CO2 level in outside air is about 340 ppm by volume. All plants grow well at this level but as CO2 levels are raised by 1,000 ppm photosynthesis increases proportionately resulting in more sugars and carbohydrates available for plant growth." -T.J Blom; W.A. Straver; F.J. Ingratta; Shalin Khosla - OMAF; Wayne Brown 

Your data suggesting the allelopathic qualities of plants are not enhanced when all other processes are when introduced to high concentrations of co2 is interesting. Stress that same plant and data would suggest allelopathic production decreases. 

Trees are mysterious.


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## John Paul Sanborn (Jul 21, 2009)

woodweasel said:


> Trees are mysterious.



And fascinating.


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