Root-applied glycinebetaine controls nitrate content and edible quality of lettuce in continuous commercial hydroponic greenhouse production

Lettuce ( Lactuca sativa L.) may accumulate high amounts of nitrate NO3− in hydroponic cultivation, such as the Nutrient Film Technique (NFT) system. The NFT system is a commonly used cultivation method which thin layer nutrient solution flows continuously over roots and then recirculated. Since id="M2">3− known to be harmful human health, lettuce producers need methods for controlling it improving quality lettuce. Here, we investigated whether root-applied glycinebetaine (GB) can control id="M3"><mml:mi content.