Salt tolerance and foliar spectral responses in seedlings of four ornamental herbaceous species¹

Tolerância à salinidade e respostas espectrais foliares em mudas de quatro espécies ornamentais herbáceas

ABSTRACT

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 Fortaleza - Ceará, 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.

Key words:
biosaline agriculture; seedling production; sensory analysis; ornamental plants; remote sensing

HIGHLIGHTS:

The Celosia plumosa tested in this study has satisfactory development with irriga-tion-water salinity up to 4.0 dS m^-1.

Dry mass reduction by salinity is acceptable to the consumer when there is no harm to visual quality.

Salinity level affects leaf spectral curves of all species, most noticeable in the visible-spectrum region.