“When Flury looked at the plants under a confocal microscope, which shines lasers that make the fluorescent dye in the plastics glow, he found particles had attached to the roots but hadn't penetrated them. So this is worrisome in that plastics might be accumulating around the roots we eat-carrots, sweet potatoes, radishes but it's good news in that neither a fibrous nor taproot system seemed to uptake plastic into the plant itself, unlike how crops readily soak up nutrients like nitrogen and iron. "The plant has probably an incentive to take up an iron particle, whereas a plastic particle will not be used by the plant," says Flury. This contradicts previous lab studies on wheat and other crops, like beans and onions and lettuce, showing that roots do take up plastics. Over at ETH Zürich, analytical chemist Denise Mitrano took a different tack, tagging nanoplastics not with fluorescence but with the rare metal palladium. And instead of growing wheat in agar, she grew it hydroponically, exposing the growing plants to the "doped" particles. She could then track the nanoplastics as the wheat plants took them up into their roots and shoots. "We didn't let the wheat go to grains, so we don't know if the nanoplastic would eventually get into the food source, but it did go up further into the plant," says Mitrano. However, she didn't see any big changes in the physiology of the plants, like growth rate or chlorophyl production. "But we did see that it changed the root structure a bit and the cellular structure in the root, which would indicate that the plant was still under stress.”