The Y(II) meter is a low cost portable field instrument that measures Bernard Genty’s fast light adapted parameter- ΔF/FM‘, ETR, PAR, leaf temperature, relative humidity, and leaf absorptance. By eliminating fiber optics, and using the latest LED technology, Opti-Sciences provides a durable instrument, based on hard science, without compromise. Y(II) is more sensitive to some types of plant stress than FV/FM. For example: Y(II) will detect heat stress at about 35oC while FV/FM will not detect heat stress until about 45oC. For more information, request the Opti-Sciences Plant Stress Guide on this website.

The FV/FM meter is companion instrument to the Y(II) meter that allow FV/FM measurements. When purchased together as the plant stress kit, there is a substantial savings compared to buying the FV/FM meter separately. FV/FM is the most used chlorophyll fluorescence measuring protocol in the world because it allows comparison of samples in the same known dark adapted state. This allows comparison of samples where the light is changing. While it is not as sensitive to some types of plant stress as the Y(II) meter, samples can be compared under canopy or situations where steady state photosynthesis is hard to measure. The FV/FM meter has an optical probe that permits measurement with dark adaptation clips, allowing fast measurement of large plant populations.

• The Y(II) meter may be purchased separately from the Plant Stress Kit
• Y(II) measurement & ETR measurement can be corrected for leaf absorptance
• Leaf absorptance measurement including leaf transmittance using RGB sensors
• PAR measurement
• Non Contact Leaf temperature measurement averaged over a large area
• FM‘ correction option at high actinic light levels, according to Loriaux 2013
• Diurnal monitoring capability designed for growth chamber work. It allows measurement day and night Useful for laboratory work
• Relative humidity sensor
• Data stored in comma delimited files
• USB port for easy data transfer

• Works with inexpensive dark clips to allow measurement of large populations quickly
• Graphic FV/FM trace display
• memory allows storage of tens of thousands of measurements
• Can be purchased separately from the Plant Stress Kit. USB port for easy data transfer

FvFm meter

Dark adapted parameters

FV/FM:Maximum Photochemical efficiency of PSII.

FV/FO:A more sensitive detector of stress than FV/FM, but it does not correlate with gas exchange.

FO:Minimum chlorophyll fluorescence.

FM:Maximal chlorophyll fluorescence.

Y(II) meter

Fast  measurements:

Y(II) or ΔF/FM’, quantum yield of PSII with the option for FM’ correction according to Loriaux & Genty 2013 included. ETR, PAR, leaf temperature, relative humidity, leaf absorptance, FS, FM’ and FT. 

        Monitor mode (for growth chamber work only): Measures the same sample for extended periods. Y(II) or ΔF/FM’, ETR, PAR, leaf temperature, relative humidity and estimates leaf absorptance. From the dark pre-dawn period data, FV/FM, NPQ, Y(NPQ), and Y(NO) can be calculated.

Y(II) Meter Specifications:

Fast measurements:

Y(II) or ΔF/FM‘ with the option for FM‘ correction according to Loriaux 2013 included. ETR, PAR, leaf temperature, relative humidity, leaf absorptance, FS, FM‘ and FT.

Monitor mode:

Measures the same sample for months at a time, using mains current. The monitor is designed for growth chamber, or laboratory work but not field work. The instrument can be programmed to measure at different intervals during light and dark periods. The monitor mode allows measurement of Y(II) or ΔF/FM‘, ETR, PAR, leaf temperature, relative humidity and leaf absorptance. From the dark period data, FV/FM, NPQ, Y(NPQ), and Y(NO) can be calculated.

Lighting conditions:

Ambient light only at steady state photosynthesis.

Light sources:

White LED saturation flash to 7,000 μmoles.

Red modulated light source (660nm with 690nm cut off filter).

Sensors:

2 RGB sensors for measurement of leaf reflectance, leaf transmittance, and leaf absorptance, calibrated with standard. From 0 to 100%.

PAR sensor measures from 400nm to 700nm, cosine corrected. +- 5%.

Pin Photodiode with a 700nm to 750nm band pass filter.

Relative humidity 0% to 100% +-2%.

Power:

Lithium-ion USB battery pack with 8 hour life. Designed to be carried in a pocket. The unit may be used with any USB compatible battery. The instrument will also run on most mains current USB chargers.

Size:

6.34″ x 1.5″ x 2.0″ (17 x 4 x 5 cm).

USB cable 32″ long (81 cm).

Battery 4.5″ x 1″ x 1″ (12 x 2.5 x 2.5 cm).

Weight with battery 0.8 lbs (0.36 kg).

Storage capacity:

200,000 measurements.

Output:

USB removable storage device standard. Comma delimited files.

Graphic screen display:

132 X by 32 pixel LCD.

FV/FM Meter Specifications:

Fast measurements:

FV/FM , FV/FO, FO, & FM.

Light source:

Array of red LEDs at 660nm.

Lighting conditions:

Dark adapted conditions only.

Light sources:

Red LED Saturation flash array up to 6,000 μmoles.

Red modulated light source (660nm with a 690nm cut off filter).

Sensors:

Pin Photodiode with a 700nm to 750nm band pass filter.

Dark adaptation clips:

10 dark adaption clips are included.

Power:

Lithium-ion USB battery pack with 8 hour life. Designed to be carried in a pocket. The unit may be used with any USB compatible battery. The instrument will also run on most mains current USB chargers.

Size:

8.5″ x 1.125″ x 1.625″ (22 x 3 x 4 cm).

USB cable 32″ long,  (81 cm).

Battery 4.5″ x 1″ x 1″ (12 x 2.54 x 2.54 cm).

Weight with battery 0.8 lbs (0.36 kg).

Storage capacity:

200,000 measurements.

Output:

USB removable storage device standard. Comma delimited files.

Graphic screen display:

132 X by 32 pixel LCD.

Specifications subject to change without notice.