Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It only takes a minute to sign up.
Sign up to join this community
Is there a point where too much CO2 is bad for a plant? Basically when there is too much CO2 in the air can a plant get sick?
Since plants photosynthesize and need CO2 to generate glucose and store starch, and since chemical reactions are pushed toward their end product when the reagent concentrations are increased, one would expect that more CO2 would be better, at least lead to increased growth and survival rates.
Is there a ceiling where CO2 gets toxic?
Short answer
It has been shown that plants may already suffer from doubling the atmospheric CO2 concentration from 340 to 610 ppm, something that might happen during the next hundred years or so based on current emissions.
Background
A popular science website tells us that an excess of carbon dioxide (CO2) reduces the rate of transpiration of some plants. This is so because the stomata, which are the openings of the leaves (Mansfield & Majernik, 1970) and used for exchanging gases as well as water vapor (transpiration) will close when there is too much CO2 in the air, or other polutants such as SO2. As transpiration drops, the water flow from the soil to the leaves also drops, causing a runoff of water.This in turn stalls nutrient uptake. Indeed, doubling the present-day CO2 concentration to 610 ppm does not necessarily lead to increased growth and may in fact inhibit growth due to excess starch formation in the leaves, indicating it's simply stored as backup energy, nothing else (Coviella & Trumble, 1999). It is believed that plants might be near their saturation point and cannot eliminate CO2 faster than they are doing right now.
Somehow plants also become more susceptible to insect foraging when CO2 concentration increases.
Note however, that CO2 tolerances are species dependent. Most research in this arena has focused on common crops. CO2 tolerance in for example cotton plants is low, and starch buildup has been observed in the entire plant, but especially in the root systems and the stem (Hendrix et al., 1994). Other species, such as wheat and rice are less prone to effects of elevated CO2 (source: Nature).
References
- Coviella & Trumble, Conservation Biology (1999); 13(4): 700–12
- Hendrix et al., Agricult Forest Meteorol (18994); 70(1–4): 153-62
- Mansfield & Majernik, Environmental Pollution (1970); 1(2): 149-54
Source
- Earth untouched
It depends upon the plant species.
As explained in Algae thrive under Pure CO2 Nature 227, pages 744–745 (15 August 1970):
Cyanidium caldarium (an algae found in Yellowstone National Park) grows much better in pure carbon dioxide than in air.
However, other plants can suffer from acidification of cell fluids at high carbon dioxide concentrations.
In Elevated Atmospheric Partial Pressure of CO2 and Plant Growth Oecologia (1979) 44: 68, it was shown that increasing CO2 concentration to 640 ppm from then-normal 330 ppm caused increased growth for both cotton (a C3 plant) and maize (a C4 plant), but the increase was much greater (100%) for cotton than for maize (20%).
According to The optimal atmospheric CO2 concentration for the growth of winter wheat (Triticum aestivum) J Plant Physiol. 2015 Jul 20; 184:89-97, photosynthesis at 968 ppm CO2 is optimal. At 1200 ppm, photosynthesis is less than optimal, but still much higher than at current ambient CO2 levels of about 410ppm.
Since you need water to live, seem you would be peachy dropped on the bottom of the ocean ;)
Organisms usually adapt to specific conditions. In particular, plants need oxygen to actually consume the glucose produced in the process of which oxygen is a byproduct. Is it possible to imagine an organism adapted to not having oxygen, by storing its own oxygen for reuse later? It sure is, and it might have been what originally happened in the original oxygen-free atmosphere. But as a matter of fact, in the current oxygen-rich atmosphere this ability would be completely useless, just as it would be for you to bring everywhere a backpack full of air to breathe. As a consequence, no mayor plant does it; and it would take centuries of evolutionary pressure to develop it.
