Protecting plants from the power of sunlight

Published July 29, 2017

Like us, plants don't like too much sunlight. MSU scientists are now proposing a way to measure, in real time, how plants prevent burn out from the sun.

Like us, plants don’t like too much sunlight. Michigan State University scientists are now proposing a way to measure, in real time, how plants prevent burn out from the sun.

The long-term goal is to make more resilient crops for improved yields to better manage the pressures of feeding billions of people or of creating green biofuels to power cars and planes.

The research team led by Stefanie Tietz, a postdoc formerly working in the lab of David Kramer, Hannah Distinguished Professor in photosynthesis and bioenergetics, in the MSU-DOE Plant Research Laboratory (PRL), has developed a new method that measures non-photochemical quenching, or NPQ, a strategy plants use to adjust to changing surroundings.

“NPQ tells us how much light energy plants are getting rid of when they are exposed to too much light,” Tietz said. “Otherwise they can burn out, even die.”

Getting rid of light, however, can slow down photosynthesis, which needs that light to produce the energy that sustains life on Earth. Consequently, plants alternate between gathering light and dissipating it, but they are not always good at keeping the balance right.

According to the study, published in the journal Plant, Cell and Environment, the new method can make movies of NPQ and photosynthesis in hundreds of plants at the same time. Experiments take seconds to complete.

The method can also make reliable measurements in the real world, either through lab simulations or directly in the field.

“We can see how the plants respond in the field, where it really matters,” Tietz said. “Then, we can use this information to guide farmers to breed better crops for particular environments, even at the level of individual farms.”

A major problem for scientists has been in measuring plant parameters, such as NPQ.

Standard techniques can take hours to complete, and they can only measure one leaf at a time. Sometimes, they can confuse other plant processes for NPQ, meaning measurements can be far off.

“This really slows down research, and we miss a lot of the important responses in the entire plant,” said Kramer, who is also a professor in the MSU Department of Biochemistry and Molecular Biology in the College of Natural Science. “The new method is not prone to the errors found in the old techniques.”

Recent research is showing that the speed at which plants adjust to changes in their surroundings is important to their health.

The team wants to find the genes that control the speed of NPQ so they can create plants with faster response times. That means less light wasted and more energy produced through photosynthesis.

“Most previous scientific work has been done in highly controlled lab settings,” Tietz said. “But as this new approach takes us into the field, we are seeing that many lab experiments don’t accurately show us what happens to plants in their natural habitats.”

The method is already being used worldwide in hundreds of labs and smallholder farms, and it is easily adaptable to commonly used scientific devices.

Tietz is still active in the PRL as a research associate in Professor Jianping Hu's lab.