Volatile metabolites controlling germination in buried weed seeds

Velvetleaf (Abutilon theophrasti Medic), morning glory (Ipomoea purpurea L.] Roth), and wild mustard (Brassica kaber D.C.] L. C. Wheeler) seeds exhibited decreased germination with increased planting depth in soil. Flushing the soil for 2 minutes each day with air overcame the inhibition. A sealed in vitro system was used to sample the volatile components produced by weed seeds. Inhibition of seed germination was accompanied by decreased O₂ levels and production of volatile metabolites identified as acetaldehyde, ethanol, and acetone. The effectiveness of these compounds in reducing germination was dependent on O₂ levels.