HIGHLIGHTS:
High levels of salt stress limit the development of basil.
High levels of salt stress limit the gas exchange and chlorophyll of basil.
The use of salicylic acid may be a strategy to mitigate the harmful effects of salt stress on basil.
ABSTRACT
The salinity of irrigation water and soil create considerable challenges in agriculture, as they harm the physiological processes and growth of plants. The exogenous application of antioxidant compounds, such as salicylic acid, can reduce the damage caused by salt stress. Thus, this study aimed to evaluate the attenuation of salt stress induced by salicylic acid in Ocimum basilicum “Cinnamon”. The experiment was performed in randomized blocks with five irrigation water salinity levels (0.5, 1.3, 3.25, 5.2 and 6.0 dS m-1) and five salicylic acid concentrations (0, 0.29, 1.0, 1.71 and 2.0 mM), with five repetitions and two plants per plot. Growth, gas exchange, and chlorophyll indices and fluorescence were evaluated 30 days after the salt treatment was applied. An increase in the salinity of irrigation water decreased the plant height, stem diameter, number of leaves, stomatal conductance, instantaneous water use efficiency, and initial fluorescence of basil “Cinnamon”. Salicylic acid was revealed to attenuate the harmful effects of irrigation water salinity on gas exchange, total chlorophyll, and initial and maximum fluorescence of basil plants.
Key words:
Ocimum basilicum; salinity; gas exchange; photosynthesis
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** Significant at p ≤ 0.01 by the F test
ns, ** - Not significant, significant at ≤ 0.01 by the F test, respectively
** Significant at p ≤ 0.01 by the F test
ns, *, ** - Not significant, significant at p ≤ 0.05, and at p ≤ 0.01 by F test, respectively
** - Significant at p ≤ 0.01 by the F test