Germination and physiological traits to ascertain the ability of hormonal priming to improve salinity tolerance in Sorghum bicolor

Abstract

Background and Objective: Salinity is the highest environmental factor that affects seedling stages negatively, thus reduces plant development and production. The objective of this study was to explore the effects of gibberellic acid (GA3) pretreatment on sorghum (Sorghum bicolor) seed germination under salt stress. Materials and Methods: Seeds were soaked in a GA3 solution (50, 100 and 150 ppm in addition to a control), dried using a drypaper, transferred to Petri dishes and treated with sodium chloride (NaCl) solutions at different concentrations (0, 2000 and 4000 ppm). Germination traits, including the length of shoot and root, the ratio of shoot to root, the weight of shoot and root, germination percentage, germination energy, germination rate and germination time and physiological traits index’s, including germination stress tolerance, seedling vigor, shoot and root length stress, fresh weight stress for shoot and root and germination speed were documented. Data was analyzed by two-way ANOVA. Treatments were arranged in a randomized complete block design, in three replications using SAS. Results: Salt stress induced by the NaCl solution significantly affected the germination and physiological traits (p<0.01). Priming seeds with GA3 (50, 100 and 150 ppm) showed a significant effect on these traits. Salt stress significantly decreased most traits, except for the mean germination time, in the absence of GA3. Increasing NaCl concentration decreased the germination and physiological traits; however, GA3 induced these traits only at the moderate salinity level (2000 ppm), whereas, no significant difference between primed and nonprimed seeds was detected at the high salinity level (4000 ppm). Conclusion: Priming sorghum seeds with GA3 play an important role in the plant response to mild salt stress.