DESEMPENHO FISIOLÓGICO DE SEMENTES DE CITRUMELEIRO ‘SWINGLE’ INOCULADAS COM Azospirillum brasilense SOB ESTRESSE SALINO

Abstract

Soil and substrate salinity interferes with plant development. Understanding the salinity tolerance of plant species and adopting strategies to mitigate its negative effects, such as inoculation with the rhizobacterium Azospirillum brasilense, may promote more efficient plant development under saline conditions. This study aimed to evaluate the germination and vigor of ‘Swingle’ citrumelo rootstock seeds under different sodium chloride (NaCl) concentrations, using A. brasilense as a potential mitigator of salt stress. The treatments were arranged in a 5 × 2 factorial scheme consisting of five NaCl concentrations (0, 30, 60, 90, and 120 mM), with distilled water used as the control, combined with the absence or presence of A. brasilense applied by pre-sowing seed immersion. Evaluated parameters included germination speed index, mean germination time, germination percentage, and percentages of abnormal seedlings, viable ungerminated seeds, and dead seeds. Primary root and shoot lengths were also measured, along with root, shoot, and total dry mass. Salt stress impaired the germination process, delaying germination and reducing seed germination and vigor. The rootstock was sensitive to salinity, and seed treatment with the rhizobacterium was ineffective in mitigating the deleterious effects of salt stress.