I believe Marine aquatic plant physiology can help also to answer that question.
Plants growing at 1, 5, 10, 20, or even 50 m undersea have different hyperbaric conditions and therefore, some effect on marine vegetation physiology should be observed.
In internet we find any kind of references like the guy who claims that plants do not stop growing under hyperbaric conditions:
"In two years a
tomato plant grown in a hyperbaric chamber grew to a height of 16 feet
and produced 930 tomatoes! That's not all! It didn't stop growing! "
at this site: http://www.geocities.com/johnh_vanbc/bible/preflood.html
An interesting question answer we find in this Web site:
Re: Can plants grow at gretaer than atmospheric air pressure
Date: Mon Feb 2 17:18:09 2004
Posted By: David Hershey, Faculty, Botany, NA
Area of science: Botany
Growing plants at above normal atmospheric pressure would involve a hyperbaric
chamber. One recent study on ginkgo found as much as a 250% increase in the
photosynthesis rate when the carbon dioxide was increased 500% and atmospheric
pressure was increased 25%. I contacted the lead author, Sara Decherd, and she
kindly told me that they found no significant effect on photosynthesis with a
25% increase in atmospheric pressure alone. She was also not aware of much
other research on plant growth in hyperbaric chambers. It seems to be an area
that has not been thoroughly studied. The ginkgo research was recently
featured in a news release, "A Lot of Hot Air: How the Dinosaurs Grew So
NASA has done work on growing plants at less than atmospheric pressure in
hypobaric chambers. Hypobaric greenhouses with one-sixteenth the pressure of
an Earth atmosphere may be required for Mars colonization.
At normal atmospheric pressures, increasing the carbon dioxide concentration
up to about 1,000 ppm often increases plant growth. Current atmospheric carbon
dioxide is about 360 ppm. Thus, you might expect a positive effect on plant
growth in a hyperbaric chamber. I doubt a soda bottle would be a satisfactory
hypobaric chamber. It would be difficult and expensive for a school student to
maintain an elevated carbon dioxide level in a hyperbaric plant growth chamber
because a plant can rapidly deplete the carbon dioxide given its low
concentration and the limited chamber volume. Be very cautious if you try to
make your own hyperbaric chamber because an explosion is always a possibility.
It would be much easier to demonstrate effects of carbon dioxide enrichment at
normal atmospheric pressures. A soda bottle system to inexpensively induce
carbon dioxide deficiency in plants can be built using rubber stoppers,
aquarium tubing, aquarium valves and an aquarium air pump (Hershey 1992,
1995). The same system could be used to elevate the carbon dioxide level using
dry ice or acid mixing with calcium carbonate as a source of carbon dioxide=