Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2003
Publication Date: June 1, 2003
Citation: Peal, L.K., Williams, R.D., Bartholomew, P.W. 2003. Seed hydration-dehydration in an allelochemical affects seed germination and seedling growth. Proceedings of Southern Weed Science Society. v. 56. Abstract p. 335. Technical Abstract: Coumarin is an allelochemical widely distributed throughout the plant kingdom. Several researchers have reported that, depending on the concentration, this plant compound inhibits or delays germination, and will inhibit or stunt radicle elongation. However, the seed germination and seedling growth studies were done with the seeds or seedlings placed in direct contact with the test solutions. Seed in the soil can go through several hydration-dehydration cycles before germination occurs. This study was conducted to evaluate the effect of hydration-dehydration of radish seed in coumarin on subsequent germination and seedling growth. Radish seed were placed in petri dishes or in seed pouches containing water (control) or coumarin solutions of 10^5, 10^4 or 10^3 M. At all concentrations coumarin inhibited or reduced seed germination and radicle growth. The greatest inhibitory effect was observed with 10-3 M. Concentrations of 10^5 and 10^4 M initially inhibited germination and radicle elongation, but after 72 h values approached those observed in the control. After 24 h germination percentages were 92%, 85%, 50% and 1% for the control, 10^5, 10^4, and 10^3 M, respectively. After 48 h the there was not significant difference among the treatments except for the 10^3 M coumarin treatment. Radicle length showed similar results. At 48 h radicle lengths were 18, 14 and 4 mm for the control, 10^5, and 10^3 M coumarin, respectively; while at 72 h radicle lengths were 46 mm, 49 mm and 12 mm, respectively. Seed hydrated in coumarin solutions for up to 5 hours and then transferred to water, or coumarin solutions showed results similar to those reported above. When the seed were hydrated and dehydrated several times in coumarin, only the 10^3 M treatment seem to have an accumulative affect. Hydration and dehydration of seed in the soil in the presence of allelochemicals may provide further insight as to allelopathic interactions among plants.