Using Chlorophyll Fluorescence to analyse plant stress

Chlorophyll fluorescence is proven to provide reliable, non-destructive information regarding the photosynthetic processes and plant health/stress.

Fluorescence tests can be easily and quickly performed by the pre-darkening of the leaf followed by short exposure to a saturating light intensity. Measuring the fluorescence intensities over time produces a Kautsky induction curve. The shape of this curve and the value of significant transient levels on the curve can be used as an indication of environmental stress damage on the photosynthetic apparatus.

Accurate Fv/Fm and OJIP analysis

Fv/Fm is the most widely used fluorescence test for plant stress detection. Fv/Fm, defined as Maximum Photochemical Efficiency, is a comparative measurement of plant stress with lower values indicating plant stress. The OS-30p+ is designed for the rapid screening of Maximum Photochemical Efficiency.

The OJIP test uses higher sampling rates to resolve fluorescence transient steps in the Kautsky curve. These steps are affected differently by different types of plant stress.

The OS-30p+ ensures the most accurate Fv/Fm and OJIP results by measuring Fo rather than offering an estimated value.

Single hand operation

The battery operated OS-30p+ features a built-in fibre optic probe, meaning that only one hand is required to operate the unit.

Lightweight leaf clips are provided for effective pre-darkening of the measurement site prior to the induction of fluorescence. These non-destructive clips are suitable for use on a wide range of plant species. Measurements are made by introducing the analysis probe to the leaf clip. The leaf clip shutter is then withdrawn, exposing the dark adapted site to a saturating excitation light source provided by a 660nm LED. Induced fluorescence is measured by a PIN photodiode at >700nm. Excitation intensity and experimental duration is user selectable.

The OS-30p+ provides a direct read-out of both the standard and an enhanced range of Fv/Fm and OJIP parameters.