In article ,
"Jeff Layman" writes:
|
| Has anyone ever tried growing under sealed polythene and increasing the
| carbon dioxide concentration in the air surrounding the plant? There is no
| point in all the sophisticated stuff if the carbon dioxide level is
| insufficient. Perhaps it is somewhat simplistic to say so, but plant weight
| is basically added through photosynthesis, water, and carbon dioxide. It
| seems to me that the first two are often controlled carefully, but nobody
| appears to experiment by increasing CO2. I assume there would be an effect,
| and maybe there is a critical concentration.
|
| Has anyone ever looked into this over here? Seems that it has been
| investigated on the other side of the pond:
| http://gvgo.ca/mb/index.php?topic=433.msg1954#msg1954

It has been looked into scientifically, because it is relevant to
global warming. The executive summary is that most plants do grow
faster with slightly higher levels of carbon dioxide, but more than
a very small increase is toxic to them. They have, after all,
adapted over many millions of years to an environment low in carbon
dioxide.

The only thing that surprised anyone was how small an increase was
needed to cause toxicity. After all, almost all foods are toxic to
almost all organisims in very high concentrations.

Note that this does not apply to some of the unicellular plants,
just as with nitrates etc. in water courses.


Regards,
Nick Maclaren.