PAZDERŮ KATEŘINA, KOUDELA MARTIN: Infl uence of hydrogel on germination of lettuce and onion seed at diff erent moisture levels. Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013, LXI, No. 6, pp. 1817-1822 The infl uence of Agrisorb (water solution 1, 3, 5 g/l) on lettuce and onion seed germination was tested in diff erent moisture conditions (30 ml and 15 ml of water in germination box). Variants with reduced water level germinated much more slowly (MGT parameter) than standard variants, though diff erences in total germination at the end of the test were insignifi cant. Treated variants of lettuce seeds showed a statistically signifi cant increase in germination energy (GE) on the fi rst day (GE1, both water levels), but a signifi cant decrease on the second day (columns GE2, 15 ml). Higher doses of Agrisorb slowed lettuce seed germination (GE2, 30 ml, dose 5 g) signifi cantly, similarly see GE2 (15 ml, doses 1, 3, 5 g). This slowdown was apparent for GE3 (both water amount) as well. A similar but insignifi cant eff ect was evident for onions. There was an infl uence of cultivar and seed vigour on sensitivity to water stress. The hydrogel application infl uenced germination of lettuce and onion seeds. Treated lettuce seeds germinated faster than non-treated control in the beginning of germination process. This eff ect was not recorded in case of slowly germinated onion seed lots. Although infl uence of Agrisorb was positive in the beginning, higher doses of hydrogel reduced germination energy of treated seed lots (for example GE2, GE4) of both crops in comparison with non-treated control. Higher doses of hydrogel caused longer MGT of lettuce and onion as well.