Abstract

Improving crop tolerance to salinity stress is a major challenge in many regions of the world towards sustaining the global food security. In this study, an interspecific difference in salinity tolerance was examined among five Apiaceae species: Caraway, celery, dill, fennel and parsley. Saline water was used at concentrations of 0, 1000, 2000 and 3000 ppm for 15 days from seed sowing (germination experiment) or for 30 days after one month of germination (early growth stage experiment). Germination rate, seedling length and leaf water content were decreased significantly with increase in salinity levels. These were associated with significant increases in Na⁺ content and significant decreases in K⁺/Na⁺ ratio. Ion leakage showed no significant changes. Germination rate and seedling length are associated greatly with relative water content and less Na⁺ content. These results suggest that inhibition in germination and early growth stage are associated mainly with osmotic stress than ion toxicity. Mostly, proline content increased significantly under salinity stress conditions. There were significant differences among species in response to salinity stress and Celery species was the most sensitive species to salinity stress compared to others.

Key words: Caraway, celery, dill, fennel, parsley, Na⁺, K⁺, osmotic stress.