Salt tolerance and foliar spectral responses in seedlings of four ornamental herbaceous species

Studies on using brackish water for the irrigation of ornamental species are still scarce, mainly considering qualitative aspects of the plants. Therefore, the present study aimed to identify salt tolerance and characterize leaf spectral responses of herbaceous ornamental species at the stage of commercial seedling production. The research was carried out from December 2020 to February 2021, under greenhouse conditions, in FortalezaCeara, Brazil. The experiment was conducted in a randomized block design with split plots, with main plots consisting of irrigation -water salinity levels (0.5, 2.0, 4.0, 6.0, and 8.0 dS m-1), and subplots by the species Catharanthus roseus, Celosia cristata, Celosia plumosa, and Chrysanthemum coronarium, with four replications. The evaluation parameters were dry mass production, visual sensory analysis, salt tolerance, and leaf spectral responses. Plant visual quality was maintained up to 2.0 dS m-1 for Chrysanthemum coronarium and 4.0 dS m-1 for Celosia cristata, Celosia plumosa, and Catharanthus roseus, which were classified as moderately tolerant at those respective salinity levels. Salinity caused noticeable changes in leaf spectral responses, especially in the visible region.