Priming enhances germination of spring maize (Zea mays L.) under cool conditions

Reduction and delay in the germination of spring maize (Zea mays L.) may be a problem due to low soil temperatures and low water potentials. However, seed priming is used to improve rate and speed of germination, and expand temperature limits for germination under normal and stressful conditions. Therefore, the objective of this study was to assess the physiological and biochemical basis of primed maize seeds under low temperature conditions. Maize seeds were subjected to hydropriming, hormonal priming with 100 mg L^-1 GA₃ or IAA solutions and halopriming with 50 mM CaCl₂ or 50 mg L ^-1 ascorbate (ASA) for 24 h. All pre-sowing seeds treatments resulted in a higher germination percentage and germination index, lower mean germination time and mean emergence time. All seed treatments resulted in higher seedling fresh and dry weight compared with that of control with maximum dry weight recorded for seeds subjected to ASA, CaCl₃ and GA₃. Performance was better in seeds subjected to CaCl₂ or ASA followed by GA₃ for 24 h than for the other priming agents. This could be ascribed to the effect of lower T₅₀, higher reducing and total sugars as well as higher α-amylase activity.