Preliminary
photosynthesis
measurements of
selected wheat cultivars
prior to inoculation
Dr. Ferenc Horváth
Dr. Barnabás Wodala
The LI-6400 Portable
Photosynthesis System
The LI-6400 Portable
Photosynthesis System
The LI-6400 Portable
Photosynthesis System
An open system
In an open system, photosynthesis and transpiration are computed
from the differences in CO2 and H2O between in-chamber conditions and
pre-chamber conditions.
Schematic without a CO2 mixer
Schematic with a CO2 mixer
IRGA (InfraRed Gas Analizator)
CO2 measurement: 4,26 μm
H2O measurement: 2,59 μm
Infrared light
source (wide
spectrum)
Gas inlet
Gas outlet
Measuring box
Indicator
Signal processing
Filter
Detector
Matching
Incoming concentrations must be stable
breath, for example, is
typically 30 000 μmol CO2
(mol air)-1
Ambient air contains 360
μmol CO2 (mol air)-1
Light
Reflected
light
PSII ΦPSII
Transmitted
light
Heat
dissipation
ETR
Mehler
reaction
PSI
Photosynthesis
Photorespiration
Chlorophyll a
fluorescence
PRELIMINARY MEASUREMENTS
Setting up the instrument (Licor 6400, an open path gas exchange system)
4 selected wheat genotypes (1 week before the infection)
PARout: sunny, depends on angle, 600 – 1800 µmol photon m-2 s-1
PARin: fixed, 1000 µmol photon m-2 s-1 (10% blue, 90% red)
Tair: 27-29 °C
Tleaf: 25-27 °C
0.7
25
0.6
Gs (mol s-1 m-2)
30
20
15
10
5
0.5
0.4
0.3
0.2
0.1
0
0
474
501
488
474
483
0.7
0.6
0.5
ΦPSII
A (µmol s-1 m-2)
Calculated parameters
0.4
0.3
0.2
0.1
0
474
501
488
483
501
488
483
Thank you
for your attention!