DUALEX SCIENTIFIC - Force-A

Dualex ® 4
scientific
FLAVONOid & CHLOROPHYLL meteR
s REAL-TIME
s GEOLOCATED
s NON-DESTRUCTIVE
s ANY PLANTS & LEAVES
s MEASUREMENTS RECORDED & SORTED

DUALEX ® SCIENTIFIC, AN INNOVATIVE TOOL
Resulting from a CNRS (National Center for Scientific Research) research team and the University of Paris-Sud in Orsay, this
new leaf-clip can simultaneously and accurately monitor the chlorophyll content in leaves and flavonoid content in the epidermis.
Versatile, it is dedicated to plant science and agronomy. Applied equally on monocots, dicots or perennials, this tool is simple
to use. Measurements are instantaneous and non-destructive. They require no prior calibration, and no sample preparation.
Therefore, measurements can either be done in the laboratory or in the field, in all conditions of temperature and ambient light.
FLAVONOID measurement
Epidermal flavonoids are absorbing UV light, and therefore
they screen the chlorophyll underneath. FORCE-A uses this
role of flavonoids as natural UV-filters to identify and
quantify these molecules.
CHLOROPHYLL measurement
The leaf chlorophyll content can rapidly and accurately be
assessed from light transmission. A first wavelength very close
to the red 3 quantifies the chlorophyll and a second in the near
infrared 4 can take into account the effects of leaf structure.
Flavonoid absorption
Absorption of leaves
Chlorophyll
Fluorescence
1
UV
LED VIS
2 3
NIR
4
200 300 400 500 600 700 800 900
A wavelength in the UV 1 is compared to a second wavelength
in the red 2 . Both wavelengths excite the fluorescence of
chlorophyll, but only UV is affected by the presence of flavonoids.
By using these two wavelengths, the DUALEX ® SCIENTIFIC
calculates a numeric value directly correlated with chlorophyll
content in the measured sample.
Flavonoid absorbance = Log
Infrared Fluo.
excited by Red
Infrared Fluo.
excited by UV
Chlorophyll content =
Infrared Trans.
Red Trans.
Red Trans.
The difference in chlorophyll fluorescence measured in the infrared
is thus directly proportional to the amount of flavonoids present
in the epidermis of the leaf.
Sampling wavelength:
UV-A
EPIDERMIS:
Rich in flavonoids
MESOPHYLL:
Rich in chlorophyll
Reference wavelength:
Red
CHLOROPHYLL INDEX (DUALEX
INDICE CHLOROPHYLLE (DUALEX® ® 4)
4)
2009 season
Partnership CIVC / FORCE-A / ESE
Chardonnay and Pinot Noir (N=109)
Differential measurement of fluorescence emitted by chlorophyll
CHLOROPHYLLE
Chlorophyll
/

Strengths
CEREALS
n LIGHTWEIGHT AND COMPACT
Very light (only 220 g, battery included) and compact (it fits
into the hand), the DUALEX ® SCIENTIFIC is easily portable and
can be used frequently. Its ergonomics is specifically designed
to measure leaves from 0.5 to over 16 cm wide.
n SIMPLE MEASUREMENTS
In automatic mode, the measurement is recorded each time
the device detects the presence of a leaf (manual triggering
also available).
VINE
n ADAPTED TO EXPERIMENTATION
The DUALEX ® SCIENTIFIC offers the option to remove the
last measurement, to manage measurement groups (three
levels of classification), and to record more than 10.000
multiparametric measurements with additional information:
date, time, group number and GPS position (meter
accuracy).
n EASY DATA MANAGEMENT
Data can be downloaded via USB in a format compatible
with any data processing software.
Free access (up to 8 cm)
n LONG AUTONOMY
Its rechargeable Li-ion high-capacity battery is guaranteed
for 1000 charging cycles. Thanks to the technology used,
the device can achieve up to 25.000 measurements for a
charging time of maximum 4 hours.
EXAMPLE OF APPLICATION: MONITORING OF NITROGEN STATUS
A NEW INDEX: THE NBI ®
Several years of research and experimentation showed that polyphenols, specifically flavonoids, are indicators of nitrogen status
of plants. Indeed, when a plant is under optimal conditions (1), it favours its primary metabolism and synthesises proteins
(nitrogen-containing molecules) containing chlorophyll, and some flavonoids (carbon-based secondary compounds). On the
contrary, in case of nitrogen deficiency (2), the plant directs its metabolism towards an increased production of flavonoids like
shown on the diagram below:
(1) Optimal conditions:
Photosynthesis
Chlorophyll
Flavonoids
(2) Nitrogen deficiency:
Secondary metabolism
By using a new indicator called NBI ® (Nitrogen Balance Index) which is the ratio Chlorophyll/Flavonoids (related to
Nitrogen/Carbon allocation), it is now possible to get an earlier information about the nitrogen status of cultures.

TECHNICAL SPECIFICATIONS - DUALEX ® SCIENTIFIC
Measured material
Measured parameters
Measurement process
Measured area
Sample thickness
Measurement area access
Acquisition time
Storage capacity
Data classification
Flavonoids
Absorbance accuracy (σ) 5%
Repeatability (σ) 2.5%
Reproducibility (σ) 3.5%
Plant leaves
Optical absorbance at a UV wavelength (flavonoid content)
Optical transmittance at 2 near-infrared wavelengths (chlorophyll content)
Main button pressure or clips closing (free choice)
5 mm in diameter
1 mm maximum
8.5 cm maximum (half-leaf width)
< 500 ms
> 10 000 multiparametric measurements
3 levels (file, group and measurement number)
From 0.00 to 3.00 (DUALEX ® units, convertible to μg/cm² after calibration)
Chlorophyll
From 0.00 to 150.00 (DUALEX ® units, corresponds to μg/cm² of chlorophyll a+b)
Repeatability (σ) 1.3%
Reproducibility (σ) 4.5%
NBI ®
From 0.00 to 999.00 (DUALEX ® units)
Temperature range From 5 to 40°C (variation of absorbance < 2%)
Light sources
4 LED: 1 UV-A, 1 Red and 2 Near Infra-Red (NIR)
Detector
1 Silicon Photodiode
User interface
LCD screen
Sound warning
Data downloading
USB connexion for data transfer
Data organisation compatible with any data processing software
Power source
Li-ion rechargeable battery
Autonomy
10 hours
Charging time
4 hours
Total weight
220 g (with battery)
Size
205 mm x 65 mm x 55 mm
Positioning
Internal GPS
Accuracy (pass to pass)
> 1 m
Languages
English, French
Safety
Ring for leash
Updating
Internet online updating
Warning: as FORCE-A is continuously improving its products, technical specifications can be changed without prior notice.
USB Interface
Ring for leach
Keyboard
LCD screen
Cartelat, A., Cerovic, Z.G., Goulas, Y., Meyer, S., Lelarge, C., Prioul, J.-L., Barbottin, A., Jeuffroy, M.-H., Gate, P., Agati, G., Moya, I., 2005. Optically assessed contents of leaf
polyphenolics and chlorophyll as indicators of nitrogen deficiency in wheat (Triticum aestivum L.). Field Crops Res. 91, 35-49.
Cerovic, Z.G., Ounis, A., Cartelat, A., Latouche, G., Goulas, Y., Meyer, S., Moya, I., 2002. The use of, chlorophyll fluorescence excitation spectra for the nondestructive in situ
assessment of UV–absorbing compounds in leaves. Plant Cell Environ. 25, 1663-1676.
Demotes-Mainard, S., Boumaza, R., Meyer, S., Cerovic, Z.G., 2008. Indicators of nitrogen status for ornamental woody plants based on optical measurements of leaf polyphenolics
and chlorophyll contents. Sci. Hort. 115, 377-385.
FORCE-A
Centre Universitaire Paris Sud, Bât. 503
91893 ORSAY Cedex - France
Tel : +33 (0)1 69 35 88 62
Fax : +33 (0)1 69 35 88 97
Opening lever
Optical emitting
head
Optical
detecting head
www.force-a.com
e-mail : info@force-a.fr
Notice Dualex ® 4 Scientific Anglaise - Edition 2 - Decmber 2010 - Document non contractuel