Author
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Conn, Jeffery |
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Beattie, Katherine |
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Submitted to: Weed Science
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/1/2006 Publication Date: 5/20/2006 Citation: Conn, J.S., Beattie, K.L. 2006. Seed viability and dormancy of 17 weed species after 19.7 years of burial in Alaska. Weed Science. 54(3):464-470 Interpretive Summary: The length of time that weed seed survive in soil is an important aspect of weed biology, knowledge of which is helpful for weed management. Weeds will continue to emerge and compete with desirable plants as long as a viable weed seed bank exists. To eradicate a new weed infestation, seed production must be prevented for the length of time that a weed species' seed survive in soil. A 50-year study at Fairbanks, AK was started in 1984 to determine soil seed longevity of 17 weed species. Seed were buried in mesh bags 2 and 15 cm deep and were recovered 0.7, 1.7, 2.7, 3.7, 4.7, 6.7, 9.7 and 19.7 yr later. Viability was determined by germination and embryo viability tests. All common hempnettle, and quackgrass seed were dead after 2.7 and 3.7 yr, respectively. Less than 1% of wild oats and foxtail barley seed were viable after 3.7 yr, but > 6.7 yr were required for loss of all viability. By 9.7 yr, < 1% seed viability remained for bluejoint reedgrass, corn spurry, pineappleweed, prostrate knotweed, and wild buckwheat. From 2- - 5% seed from common chickweed, common lambsquarters, flixweed, Pennsylvania smartweed, rough cinquefoil, marsh yellowcress, and shepherd's-purse were viable, while 62% of American dragonhead seed was still alive. After 20 yr of burial, bluejoint reedgrass seed were no longer viable, but seed of 12 other species were still viable: cornspurry (0.1%), prostrate knotweed (0.5%), flixweed (0.5%), pineappleweed (0.6%), shepherd's-purse (1.3%), wild buckwheat (1.5%), common chickweed (1.6%), rough cinquefoil (1.8%), common lambsquarters (3.0%), Pennsylvania smartweed (3.3%), marsh yellowcress (4.4%), and American dragonhead (62.2%). Seed Longevity did not appear to be enhanced by cold subarctic temperatures. Technical Abstract: A 50-year study at Fairbanks, AK was started in 1984 to determine soil seed longevity of 17 weed species. Seed were buried in mesh bags 2 and 15 cm deep and were recovered 0.7, 1.7, 2.7, 3.7, 4.7, 6.7, 9.7 and 19.7 yr later. Viability was determined by germination and tetrazolium tests. All common hempnettle, Galeopsis tetrahit L., and quackgrass, Elytrigia repens (L.) Nevski, seed were dead after 2.7 and 3.7 yr, respectively. Less than 1% of wild oats, Avena Fatua L., and foxtail barley, Hordeum jubatum L., seed were viable after 3.7 yr, but > 6.7 yr were required for loss of all viability. By 9.7 yr, < 1% seed viability remained for bluejoint reedgrass, Calamagrostis canadensis (Michx.) Nutt.; corn spurry, Spergula arvensis L.; pineappleweed, Matricaria matricariodes (Less.) C.L. Porter; prostrate knotweed, Polygonum arvensis L.; and wild buckwheat, Polygonum convolvulus L. From 2- - 5% seed from common chickweed, Stellaria media (L.) Cyrillo; common lambsquarters, Chenopodium album L.; flixweed, Descurania sophia (L.) Webb ex Prantl; Pennsylvania smartweed, Polygonum pensylvanicum L.; rough cinquefoil, Potentilla norvegica L.; marsh yellowcress, Rorippa islandica (Oeder) Borbas; and shepherd's-purse, Capsella bursa-pastoris (L.) Medik. were viable, while 62% of American dragonhead, Drachocephalum parviflorum Nutt., were still alive. After 20 yr of burial, bluejoint reedgrass seed were no longer viable, but seed of 12 other species were still viable: cornspurry (0.1%), prostrate knotweed (0.5%), flixweed (0.5%), pineappleweed (0.6%), shepherd's-purse (1.3%), wild buckwheat (1.5%), common chickweed (1.6%), rough cinquefoil (1.8%), common lambsquarters (3.0%), Pennsylvania smartweed (3.3%), marsh yellowcress (4.4%), and American dragonhead (62.2%). Seed Longevity of these species did not appear to be enhanced by the cold temperatures found in the subarctic. |
