Assessing the impact of salinity on <i>Viola</i> × <i>wittrockiana</i>: exploring morphological, physiological, and anatomical parameters

Abstract

It is critical to explore the responses of bedding plants, often planted outdoors, in light of increasing salt concerns. The potential use of these plants in salty areas and the feasibility of irrigation with alternative water sources having high salt content should be investigated. Among these bedding plants, the pansy from the Violaceae family stands out as an ornamental flower with versatile applications, particularly during winter. Pansies are commonly used in landscaping, outdoor decoration, or potted arrangements, displaying a variety of flower colors. In this study, the morphological, anatomical, and physiological responses of pansies (Viola × wittrockiana ‘Pansy Inspire Plus F1’) under salt-stressed conditions were investigated. The pansy plants were irrigated with solutions containing four different salt concentrations (0 (control), 50, 100, and 150 mM). At the end of the study, there was a noticeable decrease in several parameters, including the number of flowers, flower diameter, flower stalk length, root, and shoot growth, as well as the fresh and dry weights of flowers. Additionally, both total and mean leaf area decreased. The visual score also sharply declined. Ion leakage remained stable until the third week after it increased in groups subjected to salt application. Additionally, relative water content decreased with increasing salinity. According to SPAD measurements and photosynthetic pigment analysis, leaf chlorophyll content increased in the presence of 50 mM NaCl. This study revealed that epidermis cells and sponge parenchyma sizes increased under salinity, while leaf palisade parenchyma size decreased. Epidermis, xylem, phloem areas, and stem diameter also decreased in the stem by salinity. As a result, V. wittrockiana ‘Pansy Inspire Plus F1’ was identified as sensitive to salinity.