Effect of Seed Inoculation with a Halophilic and Growth Promoting Bacterium on Physiological and Biochemical Properties of Purple Basil under Salinity Stress

An experiment with a completely randomized design and four replications was done to study the effects of seed bio-priming of purple basil (Ocimum basilicum L.) with Halomonas sp. and to reduce the effects of salinity stress on the physiological and biochemical characteristics of this plant. The experimental treatments were control (Ctl), 0 mM NaCl + Halomonas sp. (Ctl.H), 50 mM NaCl + Halomonas sp. (S1H), 100 mM NaCl + Halomonas sp. (S2H), and 150 mM NaCl + Halomonas sp. (S3H). This study showed that bio-priming of seeds with Halomonas sp. increased the content of photosynthetic pigments (chlorophyll a by 30.16%, chlorophyll b by 34.78%, and total chlorophyll by 29.98% in S2H treatment), carotenoids (28.53% in treatment S2H), proline and protein (59.80% and 19.85% in S2H treatment), flavonoids (90.92% in S1H treatment) and also increased ascorbate peroxidase activity (74.86% in S3H treatment) compared to control. In general, purple basil seed bio-priming with Halomonas sp. leads to an increase in physiological and biochemical parameters and improve plant tolerance against salinity stress.