Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Biofeedback system designed to control photosynthetic lighting


System helps lights adapt to plants' needs in controlled environment agriculture

Controlled environment agriculture is rapidly becoming an important part of the global food system. For example, there has been much interest in the potential of large-scale, indoor agricultural production - often referred to as vertical farming - as a means to produce high quantities of produce.

A sweetpotato crop is shown in the biofeedback system. Chlorophyll fluorescence measurements are taken on the plant on the right side to determine how efficiently the plant uses the light provided by LEDs. LED light levels are automatically adjusted to maintain specific levels of physiological activity.

Photo courtesy Michael T. Martin

These "plant factories" are expensive to operate, however, in part because of the large power requirements of electric lamps that provide the type and amount of light necessary for photosynthesis in plants.

To find new methods of adapting lighting to plants' requirements in controlled environments such as vertical farms, the researchers developed and tested a biofeedback system that allows for the control of light levels based on the physiological performance of the plants.

"Controlling the intensity of light based on plants' ability to use it efficiently may substantially reduce the energy cost of LED lighting, and contribute to making large-scale controlled environment agriculture more profitable," van Iersel said.

The researchers used lettuce, pothos, and sweetpotato plants in experiments with photosynthetic light provided by a 400-Watt LED. Using chlorophyll fluorescence measurements, a datalogger determined how efficiently the plants used the light they received.

This data was used to calculate the electron transport rate (ETR), which is an indicator of photosynthesis. The datalogger then altered the duty cycle (the proportion of time that the LEDs are energized during each short on/off cycle) of the LEDs to provide more or less light.

The target ETR was altered in a stepwise pattern over a 15-h period. The biofeedback system was capable of automatically adjusting the light levels to assure that the desired ETR was reached. As the target ETR was increased, light levels increased as well. In addition, conversion of light energy into heat (a common way for plants to deal with excess light) was upregulated, while the light use efficiency decreased.

As the target ETR was decreased during the last 7 hours, conversion of light into heat decreased greatly in lettuce and pothos, with only a small increase in light use efficiency. "This suggests that the light use efficiency of lettuce and pothos was limited by a process other than conversion into heat, likely light-induced damage to the photosynthetic machinery in the leaves," the authors noted.

"The biofeedback system successfully maintained a wide range of ETR values in different species, while it also is capable of distinguishing between conversion of light into heat and damage to the photosynthetic machinery as causes for decreases in light use efficiency," the authors said. They said the biofeedback system has potential applications in controlled environment agriculture, as well as basic plant physiology studies, where the system can be used to maintain specific levels of physiological activity.


The complete study and abstract are available on the ASHS J. Amer. Soc. Hort. Sci. electronic journal web site:

Founded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at

Media Contact

Michael W. Neff


Michael W. Neff | EurekAlert!

More articles from Agricultural and Forestry Science:

nachricht Forest Management Yields Higher Productivity through Biodiversity
14.10.2016 | Technische Universität München

nachricht Farming with forests
23.09.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences (ACES)

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>