Incorporation of plant growth regulators into the priming solution improves sugar beet germination, emergence and seedling growth at low-temperature.

In a series of experiments, impact of inclusion of plant growth regulators into the KNO3 priming solution on low temperature seed germination, emergence percentage and seedling growth of sugar beet was investigated. Seeds were primed in 3% KNO3 solution for 6 days at 25 degrees C in darkness containing one of the following: 0, 0.05, 0.1, 0.5, or 1 mM acetyl salicylic acid (ASA) or 1, 3, 5 or 10 microM methyl jasmonated (MeJA). A non-primed treatment was also included in the experiment. Priming seeds in the presence or absence of plant growth regulators in general improved final germination percentage (FGP), germination rate (G50) and germination synchrony (G10-90) at 15 degrees C compared with non-primed seeds which had an FGP of 42%, G50 of 11.3 days and G10-90 of 11.7 days. Priming seeds in KNO3 solution containing 0.05 mM of ASA resulted in the highest germination percentage (89%), fastest germination rate (G50 = 5.3 days) and the most synchronous germination (G10-90 = 10.7 days). Emergence percentages were the highest for the seeds primed in the presence of 0.05 mM ASA (83%) and 3 microM MeJA (81%) while non-primed seeds had an emergence percentage of 40%. Fastest emergence rate (E50) were also obtained from seeds primed in KNO3 supplemented with 3 microM MeJA (E50 = 14.4 days) and 0.05 mM ASA (E50 = 14.4 days). Shoot fresh and dry weight of seedlings were significantly affected by treatments and priming in the presence of 0.05 mM ASA resulted in highest seedling shoot fresh and dry weight. These results indicate that priming seeds in 0.05 mM of ASA or 3 microM MeJA incorporated into the KNO3 solution can be more effective than KNO3 alone to improve low temperature germination performance of seeds and subsequent seedling growth.