Ecophysiology of <i>Mentha piperita</i> under saline stress and biostimulant in the Brazilian semiarid region

Abstract

Brazilian semiarid region has water with high levels of salts that limit its use in agriculture, necessitating the adoption of strategies to reduce the impact of salinity. The objective of this study was to assess the effect of a biostimulant as a attenuating of mitigate saline stress on the growth, gas exchange, chlorophyll indices, and chlorophyll a fluorescence of Mentha piperita. The experiment was performed using a randomized block design, employing a 5 × 5 incomplete factorial schemes. This involved five different electrical conductivities of the irrigation water (ECw = 0.5, 1.01, 2.25, 3.49, and 4.00 dS m^-1) and five doses of the biostimulant (Stimulate^® = 0.0, 1.45, 5.00, 8.55, and 10.0 mL L^-1). In total, nine combinations were generated using the Central Composite Design. Growth, gas exchange, chlorophyll indices, and chlorophyll a fluorescence were evaluated 45 days after irrigation with saline water. The results indicated that saline stress hindered the growth, gas exchange, chlorophyll indices, and photochemical efficiency of M. piperita. However, the biostimulant mitigated the adverse effects of salinity on the growth, gas exchange, and photochemical efficiency of M. piperita.