Optimized LED light spectra enhance salinity and alkalinity stress tolerance and yield performance in strawberry

• Blue/red light reduced salinity and alkalinity stress by enhancing vegetative growth, water status, and ionic balance in strawberry. • Salinity and alkalinity induce distinct physiological and mineral responses, with alkalinity more severely limiting Fe²⁺ availability and photosynthetic pigment. • Stress increased fruit soluble solids and color; light spectra differently affected yield stability and fruit quality. Salinity and alkalinity stress significantly impair strawberry growth, productivity, and mineral nutrition. Advances in LED lighting technology offer opportunities to alleviate these limitations through spectral manipulation. Here, we evaluated the effects of complementary LED light spectra, including blue (460 nm), red (660 nm), blue/red (1:3), and white/yellow (400–700 nm), on physiological, vegetative, and reproductive traits of Fragaria × ananassa Duch., cv. 'Paros', grown under salinity and alkalinity conditions. Fruit length was reduced by 24.0% under salinity and 21.3% under alkalinity, while shoot Na + concentration increased by 40.0% and 28.0% under salinity and alkalinity stress, respectively. Supplementary blue/red light significantly increased leaf dry weight under salinity and alkalinity stress compared to the treatment without supplementary light. It also increased relative water content under alkalinity stress by 34.9% and reduced root Na + concentration by 26.4% compared to ambient light. At the same time, it enhanced the uptake of K + , Ca 2+ , Mg 2+ , and Fe 2+ . Red light primarily increased reproductive performance, including primary yield, inflorescence number, and fruit formation, under salinity stress. In contrast, the blue/red spectrum was more effective in maintaining these reproductive traits under alkalinity stress. This study provides new evidence that targeted spectral manipulation of light differentially regulates water relations and ionic homeostasis under salinity and alkalinity stress. Precise light strategies can enhance strawberry resilience and productivity in controlled environments. Further work is needed to disentangle the underlying physiological and molecular mechanisms driving these responses.