Effects of the salinity-temperature interaction on seed germination and early seedling development: a comparative study of crop and weed species.

BACKGROUND: Weeds represent a great constraint for agricultural production due to their remarkable adaptability and their ability to compete with crops. Climate change exacerbates the abiotic stresses that plants encounter. Therefore, studying plant responses to adverse conditions is extremely important. Here, the response to saline stress at different temperatures of three weed species (Chenopodium album, Echinochloa crus-galli and Portulaca oleracea) and three crops (maize, soybean and rice) was investigated. RESULTS: The germination percentage of soybean notably decreased as salinity and low temperatures increased. In contrast, maize and rice consistently maintained a high germination percentage, particularly when subjected to low salinity levels. Regarding weed species, the germination percentage of C. album was not significantly affected by salinity, but it decreased in E. crus-galli and P. oleracea with increasing salinity. The mean germination time for all species increased with salinity, especially at lower temperatures. This effect was most pronounced for soybean and E. crus-galli. C. album exhibited significant reduction in stem growth with high salinity and high temperatures, while in E. crus-galli stem growth was less reduced under similar conditions. CONCLUSION: This study showed that successful germination under saline stress did not ensure successful early development and emphasizes the species-specific nature of the temperature-salinity interaction, perhaps influenced by intraspecific variability. Increasing salinity levels negatively impacted germination and seedling growth in most species, yet higher temperatures partially alleviated these effects.