EFFECTS OF GIBBERELLIN TREATMENTS ON GERMINATION OF VARIOUS SPECIES OF WEED SEEDS

Abstract

Nineteen species of weed seeds collected near Edmonton during 1957 and/or 1958 were tested periodically for their germination percentage with or without treatments with gibberellin. Most of the untreated samples were completely dormant under conditions of the test at harvest time and the majority of the dormant species remained so during a storage period of 6 months at 3 °C. ± 0.5°. Gibberellin treatments of up to 500 p.p.m. in the medium, or of up to 2,000 p.p.m. as a 24-hour pre-soaking treatment, were without appreciable effect on most of the dormant species. The chemical had a significant effect in overcoming dormancy of some, but not all, samples of wild oats. Dormant seeds of wild mustard and stinkweed were very sensitive to gibberellin treatments, while hemp nettle and blue bur showed a smaller response. Differences in results between different lots of certain species emphasize the variable complexity of conditions which at a given time may or may not be responsive to gibberellin in initiating or accelerating the process of germination.