What if you could use light to increase the flavor, aroma, color intensity, insect and disease resistance and postharvest life of edible crops? What if you could use light to increase the fragrance, color intensity, insect and disease resistance, flower timing and postharvest life of ornamental flowering plants? Sound like science fiction? It’s not.
Talking To Plants
Kevin Folta, interim chair and associate professor of the Horticultural Sciences Department at the University of Florida, says the fundamental idea of using light to manipulate plants is an old one.
“We’ve known for a long time that light can affect photosynthesis, but we are now starting to understand how light can regulate specific plant responses,” Folta says. “It’s no big surprise that light could manipulate something like flavors or any other aspect of plant metabolism.”
Working with other scientists at the university’s Institute for Plant Innovation, Folta’s initial research indicates red, far red and blue light are the three major wavelengths that affect volatile accumulation in plants. The researchers have studied the impact of light wavelengths on strawberries, blueberries, tomatoes and petunias.
“Volatiles are the chemicals that contribute to the aroma and flavor that are released,” Folta says. “Volatiles are the chemicals that are emitted that allow you to smell and taste a piece of fruit. These are the compounds that are really important in providing flavor to fruit and vegetables.”
Similar changes could be made to flowering plants by manipulating the light wavelengths that the plants are exposed to.
“For ornamentals we could affect aromas, colors and flower timing by changing the light environment — the specific wavelengths,” he says. “It would be possible to synchronize an entire greenhouse of plants to flower at the same time just by flipping a switch. By understanding the light spectrum and how a plant sees it, it could allow us to manipulate how a plant grows.
Focused On LEDs
Folta says all of the research being done involves the use of LED lights.
“LEDs allow us to deliver very precise amounts of specific wavelengths,” he says. “LEDs allow us to mix the light conditions precisely. We can pick and choose the light we want to use.”
Folta says one of the ways different light wavelengths could be used is to customize what the final fruit, vegetable or flower would look, taste and smell like.
“For example, maybe we could put the plants under blue light for a few days and then switch to far red and then red. We know that such sequential treatments allow us to bump up the pigments, then the nutrients and then the flavors,” he says. “This treatment could change the way we grow, ship and sell crops, as well as how consumers store them at home.
“All plant traits are a combination of genetics and the environment. The genetics are already in place to make a quality fruit, vegetable or flower, so the LEDs allow us to manipulate what’s already there. We can tweak the environment with the LEDs to alter plant characteristics. Maybe an LED light would be placed in a box of roses. When a consumer opens the box there would be this incredible aroma released.”
Folta says the research has tremendous potential for both edible and ornamental crops.
“This research would probably have happened a longtime ago, but LED lights were prohibitively expensive,” he said. “Now that the cost of LEDs and narrow bandwidth lighting is becoming more affordable, we realistically see LED arrays being used in greenhouses to manipulate the way plants grow.”
Possible Insect And Disease Resistance
Although the initial research has focused on changing the taste of fruit and vegetables, Folta says the use of light could easily be expanded to manipulate other plant characteristics.
“There is an increasing body of research literature that indicates some of the compounds emitted by plants and their fruit deter insects or deter fungal growth,” he says. “It may be possible that we could affect insect and disease resistance. For example, by using LED lights we could change the metabolic profile of the plant so that poinsettias would be more resistant to whitefly. This might be done by stopping production of plant compounds that attract whiteflies, or producing compounds that scare them away or, even better, may attract a predator of the whitefly.
“What we are doing is manipulating the plant metabolism or changing it in ways that we don’t necessarily understand 100 percent yet, but we know we can do it.”
An example of one of the results of the research he doesn’t completely understand has occurred with strawberry plants.
After exposing strawberry plants to LED lights, they don’t get spider mites. Folta says most of the previous research that involved the same type of plant process manipulation involved inserting a gene, spraying a chemical or other types of treatments that were labor intensive and required other inputs.
“Now we are looking at basically flipping a switch to turn on a low energy device,” he says. “Adding value at a low cost would be a great thing for the horticulture industry.”
This article was reprinted with permission from Hort Americas. Read more at the Hort Americas Corporate Blog.