PSI PlantPen NDVI 300, Instruction Manual

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GENERAL DESCRIPTION
The PlantPen model
PRI 200
measures
Photochemical Reflectance Index
(PRI) in two narrow wavelength
bands centered close to 531 nm and 570 nm.
The photochemical reflectance index (PRI = (R531–
R570)/(R531+R570)) correlates with the epoxidation state of xanthophyll cycle pigments and
photosystem efficiency in many studies under diverse conditions, such as different
1
. PRI is sensitive to
changes in carotenoid pigments that are indicative of photosynthetic light use efficiency, the rate of carbon
dioxide uptake, or as a reliable water-stress index. As such, it is used in studies of vegetation productivity and
stress.
The PlantPen model
NDVI 300
measures
Normalized Difference Vegetation Index
, which is an important
indicator of chlorophyll content in plants. The pigment in plant leaves, chlorophyll, strongly absorbs visible light
(from 0.4 to 0.7 µm) for use in photosynthesis. The cell structure of the leaves, on the other hand, strongly
reflects near-infrared light (from 0.7 to 1.1 µm). The differences in plant reflectance in the visible and near-
infrared wavelengths is used to calculate NDVI index as follows: NDVI=((NIR-VIS)/((NIR+VIS)), where VIS and
NIR stand for the spectral reflectance measurements acquired in the visible (red) and near-infrared regions,
respectively. NDVI is directly related to the photosynthetic capacity and hence energy absorption of plant
canopies
2
. The
NDVI 300
device compares reflected light at two distinct wavelengths, 660 and 740 nm.
PlantPen models
(
PRI 200-B, PRI 200-U, NDVI 300-B, NDVI 300-U) incorporate one of the two offered
communication modules: B luetooth or U SB cable. FluoPen 1.0 software provides visualization and data transfer
routines to a computer.
1
John Gamon, Josep Penuelas, and Christopher Field (1992). A narrow-waveband spectral index that tracks diurnal changes
in photosynthetic efficiency. Remote Sensing of environment, 41, 35-44.
2
Sellers, P. J. (1985) 'Canopy reflectance, photosynthesis, and transpiration', International Journal of Remote Sensing, 6,
1335-1372.