422 Water Uptake Patterns in shrunken-2 Sweet Corn (Zea mays) during Imbibition of Film-coated Seeds

Abstract

Membrane damage associated with rapid influx of water during imbibition can play a role in the poor emergence and seedling vigor associated with sweet corn germination. Film-coating as a seed treatment has been used to improve germination and vigor in sweet corn and this improvement may not be associated with changes in imbibition rate. Two seed lots of shrunken-2 variety sweet corn, low-vigor `Even Sweeter' and high-vigor `Sugar Bowl', were treated with a hydrophilic polymer film-coating and evaluated for differences in emergence and water uptake. Both cultivars were grown at 19, 21, and 26 °C with no effect on emergence due to film-coating. Imbibition curves were established for untreated and hydrophilic film-coated seeds. Film-coated seeds showed an 18% increase in fresh weight compared to untreated seeds for both cultivars during a 6-h period. Bulk conductivity tests resulted in no significant mean difference between untreated and hydrophilic-treated seeds after 24 h. These seed lots have been treated with a hydrophobic polymer and are currently being evaluated for cold temperature emergence and imbibition rates. Water entry during imbibition will also be compared for untreated sugary (su) and shrunken-2 (sh2) seeds using the fluorescent compound trisodium salt, 8-hydroxypyrene-1, 3,6-trisulfonic acid (HPTS).