Effect of Seed Treatment and Environmental Stress on Germination and Establishment of 'Sabine' Illinois Bundleflower

Abstract

Germination responses of scarified (hot water soak at 1750 F for 3 minutes) and unscarified seeds of 'Sabine' Illinois bundleflower ffiesmantbus iIIinoensis) were investigated at sub-strate water potentials of 0, -2.5, -5.0,·7.5, and -10.0 atmospheres in 50/68, 60/78, and 68/86°F temperature regimes. Scarification and warmer temperature regimes (60/78 and 68/86°F) increased cumulative germination and decreased mean germination time, whereas low water potentials decreased cumulative germination and increased mean germination time. A degraded native pas-ture in the Post Oak Savannah region was sod-seeded with scarified, unscarifled, and a mixture of scarified and unscarified seeds following suppression (herbicide, disking, or untreated) of resident vegetation. Seedling densities were greatest forscarified seeds during the first growing season because of the breaking of seed coat dormancy. However, plant densities were greatest for unscarified seeds by the third growing season because of contin-ual establishment from a dormant seed bank. Seedling and plant densities were greatest for the herbicide (glyphosate) suppres-sion treatment that created vegetation gaps without disturbing the mulch layer or the soil surface.