CID Bio-Science, Inc.

Model CI-340 - Handheld Photosynthesis Measurement System


The CI-340 Handheld Photosynthesis System is a portable, single-handed tool that measures photosynthesis, respiration, transpiration, stomatal conductance, PAR and internal CO­2. Light-weight and durable, the CI-340 was designed for field use. The optional accessory modules allow researchers to control CO2, H2O, temperature, light intensity, and measure chlorophyll fluorescence, while the ten different customized chambers accommodate any leaf size, including conifer needles and cacti. Direct chamber connection to the CO2/H2O gas analyzer reduces measurement delay and enables rapid measurement of gas exchange with minimal delays.


Photosynthesis is the formation of carbohydrates from CO2 and a source of hydrogen (as water) in the chlorophyll-containing tissues of plants exposed to light. The rate at which photosynthesis occurs is determined by measuring the rate at which a known leaf area assimilates the CO2 concentration in a given time.


It is known that transpiration is the primary determinant of leaf energy balance and plant water status. The rate of transpiration is determined by the accumulation of water vapor flux per one-sided leaf area in a given time.

Stomatal Conductance

Stomatal conductance is the water loss of a leaf’s conductance considered in parallel or series. It can be obtained by measuring the transpiration and leaf surface temperature (°C), and applying the calculation.

Open or Closed System

The CI-340 is designed so that measurements can incorporate both absolute and differential readings, simultaneously. This instrument can also be configured to operate both open and closed systems.

Absolute Readings

CI-340 measures CO2 gas concentration in the Absolute Mode from a single CO2 source. The CI-340 acquires absolute measurement both from chamber environment and inlet to the instrument. This concept adapts to both the open and closed system chamber environments unlike any other Handheld Photosynthesis System available in the market today.

Glossary of Abbreviations

  • An entire photosynthesis system in one handheld case
  • Lightweight and truly portable
  • Stable analyzer for accurate CO2 and H2O measurements
  • Open and closed system measurements
  • 9 interchangeable chambers for different types of leaves
  • Soil respiration chamber and plant canopy attachment available
  • Modular attachments include light, temperature control, CO2 / H2O supply and chlorophyll fluorescence measurement
  • Automatically controls light, temperature, and CO2 / H2O concentrations in the leaf chamber
  • Infrared non-contact leaf temperature measurement
  • Measures chlorophyll fluorescence and photosynthesis simultaneously

Main Unit

  • Main Unit: On board IRGA for CO2 Analysis,
  • H2O Analysis with humidity sensor capacitor,
  • Flow Control, Pump, Display and Key Board,
  • Leaf Chamber attachment ports and Battery.
  • Display: LCD 40 x 6 characters or 320 x 64 pixel
  • Data Storage: 4 MB Internal FLASH RAM
  • Data Output: USB
  • Flow Rate: 100 ~ 1000 cm2 / min
  • Operating Temperature: 0-45° C
  • Operating RH: 0-90% non-condensing
  • Power Supply: 7.2 VDC, 4400 mAh for 5 hours continuous use,
  • extended hours of use with additional batteries.
  • AC Adapter / Battery Charger supplied.
  • Weight: 1.5 Kg (3 Lbs) with Battery
  • Dimensions: 44 cm x 5.5 cm x 5 cm

CO2 Analyzer

  • Sensor: Low power Non-Dispersive Infrared Gas Analyzer
  • Chopping Frequency: 1Hz
  • Sensors Response Time: 35 seconds
  • Source Life: 5,000 hours
  • Measuring Range: 0 to 2000 ppm (Standard) - 0 to 3000 ppm (Optional)
  • Resolution: 0.1ppm
  • Repeatability: ±0.1 ppm (short term)
  • Accuracy: < ± 2% up to 2000 ppm
  • Sample Cell: 100 mm x 10.2 mm (3.94” L x 0.40” Dia)

H2O Analyzer

  • Sensor Type: Humidity Sensitive Capacitor
  • Stability: Stable Analyzer for accurate H20 measurements
  • Measuring Range: 0 to 100%
  • Resolution: 0.1%
  • Accuracy: ±2% at 10% RH, ±3.5% at 95% RH

PAR Measurement

  • Sensor Type: Filtered GaAsP - Photodiode
  • Measuring Range: 0 ~ 2500 µmol m-2s-1
  • Accuracy: ±5 µmol 0-2500 µmol / m2 / sec

Chamber Temperature Measurement

  • Sensor Type: Thermocouple
  • Display: LCD 40x6 characters 320x64 pixel
  • Measuring Range: -15 ~ 50°C
  • Accuracy: ±0.1°C

Leaf Temperature Measurement

  • Sensor Type: Infrared Sensor
  • Measuring Range: -10 ~ 50°C
  • Accuracy: ±0.3˚ C

This self-contained system does the work of instruments many times its size. The CI-340 measures various aspects of photosynthetic activity within a completely controlled environment—while in the field. The CI-340 creates its own environment to study plant activity, employing varied control factors including CO2 levels, luminescence, and temperature all in solid-state instrument you can carry in one hand. To measure photosynthetic activity, simply secure a leaf within the CI-340 chamber and choose “ambient” or “closed” system measurement. In moments leaf function data is available as the CI-340 analyzes photosynthesis according to your research parameters.

The entire CI-340 Photosynthesis System - Display, keypad, computer, data memory, CO2/H2O gas analyzers, flow control system, and battery - is contained in a single hand-held case. It has everything you need to measure Photosynthesis, Transpiration, Stomatal Conductance, and internal CO2 concentration, as well as many other factors. Such as: Soil Respiration, Photosynthetic Active Radiation, Barometric Pressure, Air Temperature, and Leaf Temperature. Because the chamber is connected directly to the CO2/H2O differential gas analyzer, there is virtually no time delay when measuring CO2/H2O in the chamber. With CID's carbonate injection CO2/H2O generator module, the CI-340 can precisely control CO2 and H2O concentrations in the leaf chamber.

The CI-340 can also control temperature and light intensity with the optional temperature and light control modules. Furthermore, a chlorophyll fluorescence module can be attached to the CI-340 to simultaneously measure photosynthesis and chlorophyll fluorescence.

Available Modules:

  • Temperature Control
  • CO2
  • Luminescence
  • Chlorophyll Fluorescence
  • Soil Respiration

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