Methyl jasmonate as an attenuator of salt stress on the morphophysiological aspects of red rice¹

Metil jasmonato como atenuante do estresse salino nos aspectos morfofisiológicos de arroz vermelho

ABSTRACT

The salinity of irrigation water impairs crops’ photosynthesis, growth, and development. Among the crops sensitive to salinity, red rice is one of the most affected. Methyl jasmonate (MeJa) is a plant signaling molecule widely recognized for its defense against abiotic stresses. Therefore, this study aimed to evaluate the effects of exogenous application of MeJa on the morphophysiological aspects of red rice under salt stress. The experiment was conducted in randomized blocks, in a 3 × 3 factorial scheme, with three levels of salinity of the irrigation water (0.5, 3.5, and 6.5 dS m^-1) and three concentrations of methyl jasmonate (0, 250, and 500 μM). The application of MeJa at concentrations of 250 and 500 μM showed promise in mitigating the adverse effects of moderate salt stress (3.5 dS m^-1). However, it was not sufficient to completely reverse the damage caused by the more severe salinity level (6.5 dS m^-1). MeJa concentration of 250 μM was most effective at the salinity level of 3.5 dS m^-1, demonstrating a positive impact on root length and volume, gas exchange, and chlorophyll.

Key words:
Oryza sativa L.; abiotic stress; phytohormones; salinity

HIGHLIGHTS:

Methyl jasmonate (MeJa) increased plant height and CO₂ assimilation rate in red rice under water salinity of 3.5 dS m^-1.

Salinity of 3.5 dS m^-1 reduced gas exchange, but MeJa partially mitigated these impacts at 250 µM under this salinity level.

MeJa at 250 µM improved plant growth and CO₂ assimilation under water salinity of 3.5 dS m^-1.