Solid Matrix Priming with Hydrogels on Heteropappus arenarius Seeds

Abstract

This study was initiated to evaluate hydrophilic polymers (hydrogels) as a new solid matrix medium for seed-priming of Heteropappus arenarius Kitam. Solid matrix priming (SMP)-media were prepared with the combination of Na- and K-based hydrogels and hydrogels with three different dry levels (DC; 70%, 80%, and 90%). Priming was performed in the dark at 15 or <TEX>$20^{\circ}C$</TEX> for 24 hours, and all primed seeds were incubated at <TEX>$20^{\circ}C$</TEX> in the dark for the germination test. Non-primed seeds and seeds primed with distilled water (DW) were also included. To reach the germination rate of 50% (<TEX>$T_{50}$</TEX>), it took 4.0 days for non-primed seeds, and 3.6 and 3.9 days for DW-primed seeds at 15 and <TEX>$20^{\circ}C$</TEX>, respectively. Na-based hydrogel-primed seeds with 70% DC (Na 70%) showed the fastest germination, which respectively took and 1.9 and 1.8 days at 15 and <TEX>$20^{\circ}C$</TEX> to <TEX>$T_{50}$</TEX>. K-based hydrogel-primed seeds with 70% DC showed the fastest germination among K-based hydrogels with various DC levels, but it took 0.6 days more to <TEX>$T_{50}$</TEX> compared to Na 70%. The hydration rate (HR) of DW-primed seeds was 37% lower than that of Na 70%-primed seeds at <TEX>$15^{\circ}C$</TEX> priming temperature, which indicates that Na 70% priming is the best solid matrix priming condition for promoting the germination of H. arenarius seeds.