I need help for constructing an apparatus for measuring photosynthesis

[normalman]

Hello, everybody there,,

I was searching about a scientific forum for discussing my subject; I found this forum is the nearest forum to my subject. By the way, I would like to introduce my self; I am a researcher in the field of plant physiology. I am studying the photosynthesis. A leaf gas exchange characteristic is affected by leaf boundary layer, leaf temperature, light and relative humidity (dew point). I am trying to study photosynthesis of salt marsh in the field. Actually, leaf boundary layer, leaf temperature, light and relative humidity are subjected to highly fluctuating in the field lead to large variation in leaf gas exchange characteristics (photosynthesis, leaf conductance, transpiration and respiration). I am trying to construct an apparatus for measuring leaf gas exchange in the field by using a chamber but the problem is how I can maintain constant Temperature and Relative humidity?

Yours suggestions for improving my apparatus design are highly appreciated…

Thank you very much…

 

[IceStationZebra]

What is the temp and RH range? How long? ISZ

 

[normalman]

Thanks you very much for your kind response,, The study period will be a continous measurments for about three months (Hourly time series). Temperature range will be from 19 to 24 0C and relative humidity (water vapour) range will be 60% - 80%.

Thanks again,,,

 

[IceStationZebra]

I forgot to ask how big of a chamber...

But anyway, one device that might work for the temp is a Peltier chip. You can do a google search, but essentially it moves heat from one side of the chip to the other - but the direction is dependent on the current direction. Thus one chip could both cool and heat.

For power I would look at solar and/or wind with battery storage.

As for humidity control - that is much tougher. It is easy to add moisture but tough to remove it. Some sites I ran across may spark some ideas.

http://www.coylab.com/humidity_control_glovebox.html

http://www.dampp-chaser.com/index_public_n.html

(this one looks neat but it doesn't specify how it works)

http://www.planetwaves.com/pcaredetails.aspx?id=7

http://www.hydrocase.com/index2.htm

ISZ