Inclusion of acetyl salicylic acid and methyl jasmonate into the priming solution improves low-temperature germination and emergence of sweet pepper

The effects of incorporating plant growth regulators into the priming solution on low temperature germination and emergence percentage performance of sweet pepper (Capsicum annuum 'Demre') seeds before and after seed storage were investigated. Seeds were primed in 3% KNO3 solution for 6 days at 25 degreesC in darkness containing one of the following: 1, 3, 5, or 10 mum methyl jasmonate (MeJA) or 0.05, 0.1, 0.5, or 1 mM acetyl salicylic acid (ASA). Following priming, seeds were either immediately subjected to germination and emergence tests at 15 degreesC or stored at 4 degreesC for 1 month after which they were subjected to germination test at 15 degreesC. Priming pepper seeds in the presence or absence of plant growth regulators in general improved final germination percentage (FGP), germination rate (G(50)) and germination synchrony (G(10-90)) at 15 degreesC compared to nonprimed seeds which had an FGP of 44%, G(50) of 7.3 days and G(10-90) of 7.3 days. Priming seeds in KNO3 solution containing 0.1 mM of ASA resulted in the highest germination percentage (91%), fastest germination rate (G(50) = 2.2 days) and the most synchronous germination (G(50) = 6.1 days). Emergence percentages were the highest for the seeds primed in the presence of 0.1 mM ASA (85%) and 3 muM MeJA (84%) while nonprimed seeds had an emergence percentage of 40%. Fastest emergence rates (E-50) were also obtained from seeds primed in KNO3 supplemented with 3 mum MeJA (E-50 = 15.2 days) and 0.1 mM ASA (E-50 = 15.2 days). Shoot fresh and dry eights of pepper seedlings were significantly affected by priming treatments and priming in the presence of 0.1 mM ASA resulted in highest seedling shoot fresh and dry weights. Although all priming treatments improved germination performance of pepper seeds at 15 degreesC following 1 month of storage, inclusion of 0.1 mM ASA into the priming solution resulted in the highest germination percentage (84%) and germination rate (G(50) = 3.8 days). These results indicate that priming seeds in 0.1 mM of ASA or 3 mum MeJA incorporated into the KNO3 solution can be used as an effective method to improve low temperature performance of sweet pepper seeds and that these seeds can be stored for 1 month at 4 degreesC and still exhibit improved germination performance at 15 degreesC.