TITLE:
Light Meter for Measuring Photosynthetically Active Radiation
AUTHORS:
Alexander Kutschera, Jacob J. Lamb
KEYWORDS:
Photosynthesis, Light Meter, Photosynthetically Active Radiation
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.9 No.12,
November
19,
2018
ABSTRACT: Measurement
of photosynthetically active radiation (PAR) incident on photosynthetic
organisms is a crucial measurement for understanding how organisms respond to
various light conditions, and for calculating electron flow through the
photosynthetic machinery. Measurements of PAR are typically performed in the
region of the electromagnetic spectrum between 400 - 700 nm, which is the
region of radiation that is responsible for promoting photosynthesis.
Typically, to ensure that the sensor measures in this range, the implementation
of long- and short-pass filters is required. Although this allows the exclusion
of radiation outside of the PAR region, such filters can be expensive.
Additionally, the implementation of autonomous PAR measurements requires costly
commercial instruments. Here, a straight-forward, inexpensive apparatus has
been designed and constructed using a sensor that can distinguish between red,
green, blue and white light. The constructed apparatus was able to perform comparably
to a commercial PAR sensor. Furthermore, the implementation of the device to
measure PAR intensity over a three-day period shows how the apparatus can be
implemented for use as a constant light monitor.