Ameliorating negative impacts of salinity on physiological characteristics of guava (Psidium guajava L.) by application of gibberellic acid

Since gibberellic acid has a critical role in plants tolerance to abiotic stress, therefore in present research the impact of salt water and gibberellic acid treatment on guava seedlings physiological responces were considered. The factorial experiment was carried out as a complete randomized design with four replications. Treatments included sodium chloride (0, 50 and 100 mM) and gibberellic acid (0, 250 and 500 ppm). Based on results, salinity reduced chlorophyll a, chlorophyll b, total chlorophyll, carotenoids, peroxidase and polyphenol oxidase activity, whereas it increased catalase activity. Even low salt treatment (50 mM), caused negative effects on physiological and biochemical characteristics. Gibberellic acid (500 ppm) improved physiological properties of the seedling. So, gibberellic acid application in the nurseries can be used as an effective treatment for the consequent exposure of the guava seedlings to salty soil and water.