Salicylic acid does not alleviate salt stress on physiological indicators and growth of guava

In the semi-arid region, the quality of water for irrigation stands out as a limiting factor for the expansion ofagriculture. Thus, it is extremely important to search for alternatives that minimize the effects of salt stress onplants. Foliar application of salicylic acid stands out among these strategies. In this context, the objective ofthis study was to evaluate the gas exchange, photosynthetic pigments, and growth of guava as a function ofirrigation water salinity and exogenous application of salicylic acid in the post-grafting stage. The experimentwas conducted under greenhouse conditions, in a randomized block experimental design, in a 2 × 4 facto rialscheme, corresponding to two levels of electrical conductivity of irrigation water (0.6 and 3.2 dS m-1) and fourconcentrations of salicylic acid (0; 1.2; 2.4 and 3.6 mM), with three replicates. Irrigation with water of 3.2 dS m-1caused reductions in transpiration, CO2 assimilation rate, instantaneous water use efficiency and instantaneouscarboxylation efficiency of guava, at 150 days after transplanting. Water with electrical conductivity of 3.2 dSm-1 reduced the growth in stem diameter and the absolute and relative growth rates, as well as the relativewater content, and chlorophyll a and b contents of guava plants. The interaction between water salinity levelsand salicylic acid concentrations did not influence the physiological indices and growth of guava in the postgraftingphase.