Tomato is one of the most important vegetables in Colombia. This crop is sensitive to salinity, so high salt concentrations in the soil can negatively affect its growth and development; tolerance levels vary among cultivars. A viable strategy used in other cultivated species is the application of phytohormones that help plants acclimate to variable environments. Since few studies report the influence of growth regulators that alleviate this type of stress in tomatoes, this research aimed to determine the effect of different naphthaleneacetic acid and gibberellic acid doses on some physiological and growth parameters in tomato plants subjected to saline stress. We implemented a randomized design with a 2 × 6 factorial scheme. The first factor corresponded to salinity with two levels (0 and 40 mM), and the second factor involved the individual application of hormones (auxins – naphthaleneacetic acid (NAA) and gibberellins – gibberellic acid (ProGibb SP®)) at doses of 50, 75, and 100 μM each, for a total of 12 treatments with six replicates. We evaluated growth variables such as plant height, number of leaves, leaf area, fresh biomass of the aerial part and roots, as well as physiological variables of chlorophyll content and stomatal conductance (gs). The application of gibberellins at 100 μM demonstrated the ability to mitigate the deleterious effects of salinity on some growth parameters in tomato plants by improving leaf expansion and aerial fresh biomass.
Ruiz-Berrío et al. (Wed,) studied this question.