Time to Celebrate Photosynthesis

Bud-Break in Canada

Time to Celebrate

Leaves on a bush

Research, Teaching, Industry

Twenty-six years ago, Qubit’s first products were designed to provide affordable photosynthesis measurements in the laboratory and the field. Since then, we have continued to develop a broad range of accurate, rugged, and cost-effective products to monitor photosynthetic rates in both terrestrial and aquatic environments, as well as providing ancillary equipment for gas monitoring and environmental control. Our PhD-level staff scientists have published extensively in the field and are always available to assist you in selecting the most appropriate technology for your applications.

Gas Exchange Systems

Q-Box CO650 Plant CO2 Analysis Package

Modular or Integrated

It’s your choice. Choose Q-Box Qubit’s CO650 Plant CO2 Analysis Package ($12,500 US) if you prefer a modular design in which the CO2 analyzer, water vapour analyzer, pump, and mass flow monitor are configured as a system but can be easily detached for independent use.

Choose one of Qubit’s integrated packages in which all components are housed in a smaller case for even greater portability.

The accuracy and dependability are equally excellent. Our temperature-controlled leaf chamber with an LED light source regulates leaf temperature from 5C to 45C with rapid switching to selected levels.  Intuitive software stores raw data and calculated parameter data and has numerous mathematical and statistical functions.

Differential Oxygen Analysis
(1ppm resolution)

S104 Differential Oxygen Analyzer
S104 Differential Oxygen Analyzer Data

Qubit’s S104 DOX Differential O2 Analyzer is the only patented instrument capable of resolving 1 ppm O2 against a background of air, allowing instantaneous measurements of photosynthetic O2 exchange rates in an open-flow gas exchange system. When combined with CO2 exchange rates, this allows measurement of changes in photosynthetic and respiratory quotients, providing unique insights into photosynthetic and respiratory reductant fluxes. Measuring CO2 exchange rates in conventional gas exchange systems tells less than half the story.

Notable publications

  • P. Davey et al. (2004)  Respiratory Oxygen Uptake Is Not Decreased by an Instantaneous Elevation of [CO2], But Is Increased with Long-Term Growth in the Field at Elevated [CO2]. DOI: https://doi.org/10.1104/pp.103.030569
  • YP Cen et al. (2001)  Whole-Plant Gas Exchange and Reductive Biosynthesis in White Lupin. DOI: https://doi.org/10.1104/pp.126.4.1555

Gas Mixing and Control Systems

Mass Flow Controllers

Qubit’s mass flow controllers are available in ranges from 0 – 1mL/min maximum to 0 – 500L/min maximum. They can be combined to provide automated gas mixing of up to 9 gases with ultra-precise accuracy. Each mass flow controller has calibrations for 130 gases and can be used interchangeably. Pre-programmed mixtures can be deployed with the click of a mouse. More

Qubit’s PID gas control systems can provide gas mixtures to gas exchange systems and regulate gas concentrations in chambers within narrowly-defined set points. Monitoring plant growth under elevated CO2 or CO2-limited conditionsexposure to other physiologically active gases, and controlling humidity conditions are common applications of our gas mixing systems.

Algal Photosynthesis

Algal Photosynthesis

Gas Exchange

Qubit’s low-cost FL23 Algal CO2 Package ($5,900 US) monitors headspace CO2 levels above algal suspensions supplied with controlled gas flow from Qubit’s gas control systems. Photosynthetic rate is monitored in the light when the cuvette is illuminated with an LED light source, and respiration is monitored in the dark.

Qubit’s S151 NDIR CO2 analyzer can also be used in conjunction with submersed membrane technology for extremely high-resolution measurements of dissolved CO2 directly in the growth medium.



Photobioreactors are available in volumes from 400 mL to hundreds of liters. All are equipped with controllable LED lighting (irradiance level and spectrum) from a back panel. Temperature, pH, and dissolved gas levels may all be controlled in software. OD is measured continuously, and chlorophyll fluorescence kinetics may be measured by a range of automatic protocols.

A low-cost multicultivator (pictured above) allows 8 different cultured to be grown and analyzed simultaneously and independently.

Dissolved Oxygen Measurements

Photosynthesis (and respiration) in algal suspensions and isolated organelles can be measured in our OX1LP Package which consists of a high-resolution polarographic O2 electrode coupled with one of several water-jacketed cuvettes ranging in volume from 1 mL to 50 mL. A magnetic stirrer is provided and an LED light source is optional. The volume of each cuvette can be reduced to 20% of the maximum by adjusting the plunger. Metabolic effectors can be injected using a Hamilton syringe. The OX1LP Package starts at just $3300 US including software and interface.

I have tried three different systems based on Clarke-type electrodes including this one, and this is by far the most convenient for use with small sample volumes and gives a very clean, repeatable trace with the best signal to noise ratio I ever had with micro-chambers.

Dr. Inna Sokolova, Assistant Professor, Biology Department, University of North Carolina at Charlotte
A255 Magnetic Stirrer

Teaching Photosynthesis

Q-Teach Plant CO2 Package

Q-teach Package ($3800 US)

Qubit’s new Q-teach Plant CO2 Package is designed for teaching the principles of photosynthesis, respiration, and transpiration in leaves placed in a flow-through chamber. The package includes everything required by the instructors: NDIR CO2 analyzer, gas pump/flow monitor, RH/Temperature sensor, leaf chamber, LED light source calibrated in software for PAR output, 6 gas bags, accessories, data interface, software, and experimental files with all experiments and calculations outlined. Operational and laboratory experiment manuals are also included.

Qubit’s educational packages are hard to beat. As tools for teaching students the principles of photosynthesis and nitrogen fixation, they are great value!

Dr. Warwick Silvester, Department of Biological Sciences, University of Waikato, Hamilton, New Zealand

Contact us with your specific needs. We can customize our systems for your application.