Effects of salt stress on germination, seedling growth, and ion content of sweet sorghum

Abstract

Salinity is one of the most common abiotic stresses in the world. It negatively affects the growth and development of sweet sorghum (Sorghum bicolor L. Moench). It significantly reduces germination and seedling growth parameters. The present study was carried out to evaluate the impact of four salinity levels (0, 100, 200, and 300 mM) on the germination and seedling growth parameters of four sweet sorghum genotypes (Erdurmus, Uzun, Srg 156, and BSS 424) and on their ion content (Na, K, Ca, and Mg). The results indicate that under nonsaline conditions, the germination percentage (GP) of all genotypes was 100%, and Erdurmus was identified as the earliest germinating genotype. The BSS 424 genotype showed a significant reduction in germination index (GI), ranging from 8.33% at 100 mM to 0.89% at 300 mM, while Erdurmus and Srg 156 showed the lowest decreases, with mean values of 15.801 and 13.901, respectively. The highest root fresh weight (RFW) value was observed in the control for all the genotypes, while Erdurmus showed the lowest decrease. Moreover, the highest decrease in Mg (0.24%) and Ca (0.17%) content was observed in Uzun, and the lowest K content was identified in BSS 424 (0.5%), whereas the highest Na content was also determined in Uzun (3.12%). Considering all the results, salt stress above 200 mM significantly affected the germination and seedling growth parameters. Therefore, lower concentrations should be taken into consideration for sustainable sorghum production.