Germination and root growth of 4 osmoconditioned cool-season grasses

Abstract

Establishment of grass species used in range reseeding should improve if germination time can be decreased. Osmotically controlling the hydration of seed so that germination processes proceed other than radicle emergence (osmoconditioning) can decrease germination time of many plant species. Growth chamber esperiments were conducted to evaluate effects of osmoconditioning at -1.5, -2.0, and -2.5 hlpa for 4,8,12,16, and 20 days on germination and root growth of ‘Flintlock’ western wheatgrass (Pascopyrum smithii (Rydb.) A. Löve) and ‘Vinall’ Russian wildrye (Psathyrostuchys juncea (Fischer) Nevski) and at -2.0, -2.5, and -3.0 hWa for 4, 8, 12, 16, and 20 days on ‘Nordan’ Crested wheatgrass (Agropyron desertorum (L.) Gaertn.) and ‘Tegmar’ intermediate wheatgrass (Agropyron intermedium (Host) Beauv.). A second study looked at germination time of seed from the same species conditioned at osmotic potentials and durations producing the shortest time to 50% germination (optimum conditioning) and air dried for 0, 1, or 7 days. Conditioned seed of Russian wildrye and western wheatgrass germinated 2 to 4 days faster, respectively than untreated seed. Optimum conditioning of seed from all 4 species produced seedlings with roots 20 to 67% shorter 4 days after germination than seedlings from untreated seed. Conditioned western wheatgrass seed continued to germinate faster than untreated seed after being air dried for 7 days. Slow root growth from conditioned seed may negate any benefits derived from rapid germination.