Inducing salt tolerance in french marigold (Tagetes patula) through seed priming

The present study investigates the potential of seed priming for induction of salt tolerance in French marigold at early growth stage. Treatments were combination of priming techniques viz. hydropriming, halopriming (50 mM CaCl2), hormonal priming with salicylic acid (100 ppm) and ascorbate priming (100 ppm) each for 24 h. Primed seeds were exposed to salinity levels (0; 50 and 100 mM NaCl) during germination and emergence assays. All priming treatments hastened germination and emergence attributes under saline or non-saline conditions as compared to those of non-primed (control) seeds. Seeds of French marigold primed with ascorbate followed by CaCl2, salicylic acid and hydropriming enhanced final germination, speed of germination, root and shoot length and dry mass of French marigold seedlings. This was interpreted by minimized mean emergence time and time to 50% emergence. Additionally, it was also observed that all priming agents particularly calcium salt and ascorbate maintained ionic homeostasis in salt stressed seedlings. It is concluded that CaCl2, ascorbate and salicylic acid were the most effective priming agents to ameliorate the adverse effects of salinity in French marigold due to lower uptake of Na+ and higher uptake of K+ in the seedlings.