Hydropriming has both positive and negative effects on seed performance. Hydropriming (for 6 to 30 h) was performed in the maize {Zea mays L.) seed iines TSK 11' and 'PS 54'. A short hydropriming time of 6 to 12 h improved seed germination in both lines. An improvement in seed vigor, as investigated by germination after accelerated aging, was observed after hydropriming for 6 and 12 h in TSK 11' seeds, but only after 6 h of hydropriming in 'PS 54'. The reduction in seed vigor occurred faster in 'PS 54' than in 'TSK 11', which was confirmed at hydropriming times of 12 and 18 h, respectively. The higher activities of antioxidant enzymes, that is, Superoxide dismufase (SOD) and ascorbate peroxidase (APX) in 'TSK 11', and SOD, peroxidase (POD), and APX in 'PS 54', correlated with enhanced maize seed vigor after priming. The deterioration of primed maize seeds was linked to the process of lipid peroxidation, indicated by the generation of malondialdehyde during imbibition, and acetaldehyde and ethanol during redrying. Additional indicators were identified: a reduction in the antioxidant activities of SOD, GAT, and APX for 'TSK 11 ', and SOD and CAT for 'PS 54', decreased raffinose content, and increased amylase activity. A less compact cellular ultrastructure was observed in hydroprimed seeds and was associated with seed deterioration. The different responses in physiological and biochemical attributes induced by hydropriming were related fo their genotype and partially affected by fhe initial characferisfic differences befween fhe two maize lines causing different maize seed appearance.

Two cultivars of seeds from the National Corn and Sorghum Research Center (NCSRC) and a Private Company (PC) were hydroprimed for 3 to 12 h, then artificially aged at 42C, 100% RH for 96 h. The germination of NCSRC unprimed seeds after accelerated aging was greater than the PC seeds caused by its initial ascorbate peroxidase (APX) activity. Hydropriming for 3 to 9 h prevented any loss in germination due to the aging process. However, this effect was inhibited by hydropriming for a longer duration. The amelioration of the aging process may be due to a reduction in oxidative stress by antioxidant enzymes. Superoxide dismutase (SOD) and APX may play a role in NCSRC, but APX only contributed in PC seeds. The high amylase activity with remaining glucose content may associate to improve germination in the hydroprimed with aged seeds. Hydropriming periods of greater than 9 h resulted in loss of seed germination after accelerated aging. This result was caused by a reduction in sucrose and raffinose content. The sharply increased amylase activity for both cultivars and the decreased activities of SOD and APX in NCSRC and APX in PC may also indicate the loss of primed seed vigor.

No abstract

No abstract