Effects of seed priming with ABA and SA on seed germination and seedling growth of sesame (Sesamum indicum L.) under saline condition

Abstract

In order to investigate the effect of seed priming with ABA and SA on germination indices of sesame in saline conditions, an experiment with three factors and four replicates arranged in completely randomized design. The first factor was type of growth regulator as ABA and SA, the second factor was concentration of growth regulator including 10, 50 and 500 ppm and the third factor was NaCl salinity (0, 2, 4, 6 and 8 dS/m). Seeds were soaked for 6 hours in distilled water, ABA or SA solutions, after which the solution was eliminated and the seeds were dried, deposited in separate Petri dishes between two filter papers and watered. During a 10-day period, germinated seeds number were counted daily and at the final day, randomly selected seedlings were weighed (fresh and dry) and their plumule and radicle lengths were recorded. The results showed that salinity decreased germination rate (GR) and uniformity (GU), but 10 and 50 ppm ABA or SA supply induced higher GP and GU at 4 dS/m and above, more pronounced at 8 dS/m. SA with 500 ppm concentration; however, impaired seed viability. On the contrary, plumule and radicle lengths of seeds primed by 10 and 50 ppm ABA and SA tended to be lower at 0, 2, 4 and 6 dS/m and higher at 8 dS/m than non-primed control. Almost similar results were obtained for seedling dry mass, although the effects of SA were more drastic. Overall, the results suggest a considerable ameliorative effect of ABA and/or SA seed pretreatment on germinability of sesame seeds under salinity but seedling growth may be retarded which is probably an acclimation and temporary response to salinity stress.