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.

Salicylic Acid in Root Growth and Development

“…The genotype specificity of SA effective concentrations may explain the wide ranges reported to increase root length in tomato (0.1-100 µM) and rice (700 µM-1 mM) and to decrease root length in Arabidopsis (3-250 µM) [9,25,26,56,73,80,81,[124][125][126][127][128][129][130]. In most species, there are only a few papers reporting only decreases or only increases in root length after an SA treatment (Table S2) and similar SA doses may enhance (1 µM-5 mM) or suppress (0.7 µM-10 mM) root growth depending on the species [42,79,83,97,[131][132][133][134][135][136][137][138][139][140][141][142]. SA controls root growth by regulating root apical meristem (RAM) activity [12,25,143].…”

“…The effective SA concentration depends on plant species and stress severity. SA priming of sesame (70-350 µM) and wheat (15 µM) seeds mitigated salinity-induced (40-50 mM NaCl) inhibition of seed germination [71,97]. SA priming of mungbean (0.01 µM), fenugreek (15 µM), Arabidopsis (50-500 µM), wheat (0.3-1 mM), and barley (1 mM) seeds alleviated even higher salinity levels (100 mM NaCl and more) [72,75,77,114,122,237].…”

Seed Priming with Phytohormones: An Effective Approach for the Mitigation of Abiotic Stress

“…The deterioration of Agropyron elongatum seeds was prevented by priming them with ABA at 50 ppm, which enhanced antioxidant enzyme activities [ 8 ]. Under saline soils, good stand establishment of sesame ( Sesamum indicum ) was achieved by ABA seed priming [ 111 ]. Zongshuai et al [ 112 ] reported that the salt tolerance of wheat plants was enhanced by seed priming with ABA.…”

Molecular dynamics of seed priming at the crossroads between basic and applied research

“…The use of different phytohormones as priming agents has become an established approach with proven beneficial effects in promoting plant stress tolerance (Rhaman et al 2021 ). Successful seed priming has been reported using auxin (indole-acetic acid, IAA) (Eisvand et al 2010 ; Fahad et al 2015 ), cytokinins (CKs) (Bryksova et al 2020 ), gibberellins (GAs) (Ghobadi et al 2012 ; Ma et al 2018 ), and abscisic acid (ABA) (Gurmani et al 2011 , 2013 ; Wei et al 2015 ; Zongshuai et al 2017 ; Safari et al 2018 ). Seed priming with ethylene-related compounds was applied to lettuce ( Lactuca sativa L.) to increase germination under high temperatures (Nascimento et al 2004 ).…”