>CP are not know for high photosynthetic activity, rather the opposite. (...)
>I don't think there is a lack of CO2.
This is a good point. I don't think so, either. Most cp do trap their prey
in order to supplement their nutrition with N and/or P, not C.
The CO2 partial pressure will however influence the acidity of at least the
extracellular fluid, i.e. force the plant to react to these conditions, and
this might induce a (transitory) growth response.
But for the reasons above, I would assume that CO2 will not really
substitute animal prey (or the salts used in TC).
>Has anybody measured CO2-concentrations?
>Is there a easier way than using a IRGA (InfraRed GasAnalyser:-)?
I do not know of attempts with cp. There may be "easier" ways in terms of
apparatus (BaCl2 trap &c.) but with these it is certainly not simpler to
obtain results than in IRGA. ;-)
Kind regards
Jan