Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/6/1997
Publication Date: N/A
Technical Abstract: Studies were conducted in an agricultural soil seed bank near Ames, IA, to determine changes in seed germinability on a bi-monthly basis over two years. Seed was extracted from soil cores drawn from this seed bank every two months, and germination assays conducted immediately after extraction from the soil. To precisely assess germinability states in the seed, three germination assays were conducted: embryo only, embryo surrounded by other caryopsis tissue (caryopsis germination), embryo surrounded by caryopsis tissue, as well as the hull (seed germination). Predictable changes in germination were observed: seed germination was observed in the spring of each year for giant foxtail, and twice a year for green foxtail (spring, fall). Caryopsis germination was greater at all times of the year than that of the seed. Embryo germination was greatest of all the three seed compartments at most times of the year. Both caryopsis and embryo only germination occurred in a predictable pattern over the annual cycle. Seed germination only occurred at those times of the year when both caryopsis, and embryo only, germination was very high. These and other observations provided support for an annual cycle of seed germinability changes (see Baskin and Baskin, 1985, Bioscience 35:492), as well as support for the three compartment model of foxtail seed germinability (Dekker et al., 1996, Amer. J. Bot. 83:979).