I found this system good. However, I found best LiCor XT 6400 for gas exchange measurements.

I can Rank IRGAS as

1- LiCor XT 6400

2- CIRAS, PP systems

3- LCA-4; or LCPro, ADC, UK

4- CI-340

The main difference is user friendliness and carryover to fields or working within lab with different kinds of plant species..... canola, wheat, maize, grass, tobacco, sorghum, sunflower, Ocimum, soybean. You may face problem of use of different kind of chambers due to different kind of leaves OR measurements taken at eleavated level of CO2. So if you dont buy, I sugest you Licor, which is upgradable, adjustable for chlorophyll fluorescence measurements as well.

I had work with both systems, the CID and the Li-6400. Obviously the Li-Cor gives a lot more of precision and allows much more versatility for working with PAR radiation, Temperature, CO2 etc... However CID is not a bad instrument and is way more cheaper.

As Habib, my vote goes to the Li-COR if you don't have a budget limitation, if you do and you are seeking to obtain orders of magnitudes for gas exchange (big differences in irrigation treatments in agricultural crops like in my case) the CI-340 is not a bad instrument.

Also I worked with a very old ADC equipment and I don't recomend it.

I would add to the list of good equipement the Walz photosynthesis system... Which is in many respects similar to the LICOR.

If you work in difficult places (on trees climbing long walks) You might wish to go for the CID because of the weight...

I do not know the device, but for its simplicity and practicality, it serves for monitoring and not for research. I work with the LI-COR that is very reliable and accurately reflects what happens in terms of photosynthesis.

I have mainly worked with the LICOR 6400 (XT) and the Walz GFS-3000 and they are both very accurate instruments. The Licor might react a little bit faster as it carries the analyzer directly in the measuring head. The advantage of the Walz is that you can regulate humidity (with a humidifier + a drier) and that when measuring fluorescence and gas exchange at the same time you can use a larger leaf chamber (which will give you more accuracy for the gas exchange measurement).

Very good advices, thank you all. I was looking for a accurate device and in the same time with a quick measurement (stabilization). I worked with LICOR 6400, it was very good, but now I'm needing a faster device with similar accuracy. I'm performing essays with many plants, and we need data from all of them. Anyone can tell me about the antagonism between quickness and accuracy among these advices. What is the fastest?

Dear James Gattward, I prefer accuracy than speed. The data obtained will be of greatest value for high-impact publications. I have seen that some journals refuse manuscripts when there is no assurance of data accuracy.

Dear James Gattward, I agree with Marcelo about the utility of CI-340 in screening for larger differences but not for accuracy. Licor 6400 and XTs have patented the best possible design of IRGA sensor location for accurate gas exchange measurements with some limitations vis a vis larger chambers due to moisture issues. If only stomatal conductance and transpiration need to be measured you may get even a cheaper porometer for something around $1500. Since you did not specifically mention gas exchange as a must, for both accuracy and speed the other alternative, albeit as expensive as Licor's could be the WALZ PAM fluorometers such as PAM 2500. This gives among many other parameters the ETR measurements as a proxy for rates of photosynthesis and the machines are much lighter and user friendly too.

I need Licor 6400 as a number one tool to measure Leaf Gas Exchange. caused I want measure PN, gs, Ci, WUE, light response curve, CO2 in different concentrations (ACi curve), ... etc.if It is perfect instrument and iif my or your organization need howabout its price.

Yes LICOR-6400XT is very good instrument, if budget is not the main consideration, you can go for this.

Dear Scientists, can any one tell me about the price of Hand-held Photosynthesis Systems and Hand Held Leaf area meter. I will be highly pleased if any one send me price @ [email protected]. Thanks in advance.

Licor and Walz are both several 10000 of Euros. One concern that I have as field scientist working with trees in natural area is the weight and portability of the LICOR. I am not sure how important are the analyser accuracies. My feeling is that cuvette leakage etc are far more important than analyser accuracies. But I work with trees outside.....

Thanks Frank Berninger for your kind information.

 What about the price of CI-340 Hand-held Photosynthesis System?

It`s not cheap. I remember some years ago to be about 3/4 of the LICOR-6400 price 

I am also looking into a field system for measuring photosynthetic rates in grasses.  I was pretty shocked by the price of the LiCOR 6400, and now they are coming out with a  new and improved model (LiCOR 6800F) that is about $5000 US more expensive! Apparently it has a larger chamber size for improved accuracy and maybe some other improvements to the chamber.  I wish I had bought the 6400 system a couple years ago, before the Canadian exchange rate got so high, but at around $50,000 US, the LiCOR systems are out of my price range.  Now I am looking for something equivalent that is less expensive, but as reliable.  The CI-340 doesn't seem appropriate.  Can anyone quantitatively compare the CIRAS-3 with the WALZ PAM and the LiCOR 6400? 

https://cid-inc.com/plant-science-tools/photosynthesis-measurement/ci-340-handheld-photosynthesis-system/

http://ictinternational.com/products/ci-340/ci-340-photosynthesis-system/

http://www.damarus.com/product/68/ci-340-handheld-photosynthesis-system.htm

https://www.somatco.com/CI-340_Hand-Held_Photosynthesis_System_D156-53.pdf

http://www.es-france.com/pdf/CI-340.pdf

I bout LAI 2200 canopy analyzer, the cost was about 7000 euros, it was not functional for other measurments ,because it measures just crop canopy, i would like to buy other device to measure photosynthesis, transpiration and transpiration, LAI but cheaper than LAI 2200,

I have a LiCOR 6400 which was is not functional anymore due to fire. I am looking forward to exploring the PP models. I appreciate the discussion going on.

I am using it with my students, and relatively it is very important instrument in crop physiology studies, for you can collect many parameters at a time that are useful to come to conclusion. However, it demands good handling and the status of the instrument, conditions when measurement is carried out, type of leaves sampled, the pre-measurement exposure of the leaves sampled to sun. Support of the instrument so crucial and the height must be adjustable, for some times leaves are damaged during measurement. In general, we are happy to have and use the instruments.