Light intensity and quality control system for plant imaging
Published: 7 October 2014
This system is designed to control the quantity and quality of light received by plants over time. Plants can be exposed to different light/dark cycles (e.g. short day and long night) with different light intensities and quality (i.e. different colours).
This system is designed to control the quantity and quality of light received by plants over time. Plants can be exposed to different light/dark cycles (e.g. short day and long night) with different light intensities and quality (i.e. different colours).
Ready made software can switch the light system on and off automatically, after setting some parameters such as the length of the days and nights. Two sets of high power LEDs (currently blue and red) are powered by 2 different power supplies, which allow separate control of their respective intensities. Virtually any LED (e.g. any colour) can be plugged to this system. Their intensity is set manually, and different combinations of light can be set.
This light control system is not only used to set the length of days and nights. Light is also monitored with a photon counting camera and software.
In the experimental application modified plants contained the luciferase (luc) reporter gene. The luciferase enzyme (also found in fireflies) produces very small amounts of light that can be recorded by our camera. To do so and get images, plants must be in complete darkness when the photon counting camera is on. However, the plants need some light between each image during the day. Our imaging system allows us to control simultaneously the light and the camera. Light emitted by plants can then be quantified by a software. The set up therefore permits the experimenter to follow gene expression automatically over time, using different gene promoters fused with luc.
We can also plug in an “automated covering system” to keep the roots in darkness. Indeed, light can affect some gene expression in the roots. If so it is better to keep the roots in a dark environment (as they usually are, e.g. when grown in soil). When we grow plants on vertical plates, we can therefore keep the root compartment in the dark while the shoot compartment is exposed to different light intensity or quality. This covering system is controlled by the same software. Thus our imaging system can now control simultaneously the light (on shoots), the cover (on roots) and the camera.
This system can be used more generally for any application which requires different quantity and quality of light with auto shutter (cover) at different times.
First published: 7 October 2014