Abstract

AZANIA, C.A.M.; MARQUES, R.P.; AZANIA, A.A.P.M.  and  ROLIM, J.C.. Overcoming dormancy of Ipomoea quamoclit and I. hederifolia seeds. Planta daninha [online]. 2009, vol.27, n.1, pp. 23-27. ISSN 0100-8358.  http://dx.doi.org/10.1590/S0100-83582009000100004.

An experiment was installed in Ribeirao Preto-SP to test the use of water as a method of overcoming dormancy of Ipomoea hederifolia and I. quamoclit seeds. Before carrying out the treatments, the seeds of the two species were submitted to tetrazolium test to assess their viability. The treatments consisted in submerging the seeds of both species in hot water at boiling point (98 ºC) and in water at ambient temperature (26 ºC), during different periods of exposure (null; 0,5; 1; 5; 10; 15; 20 and 24 hours). Seedling emergence was determined daily, for 21 days, for posterior calculation of emergence speed rate and emergence speed. The Ipomoea species presented a differentiated behavior. The I. hederifolia seeds subjected to the hot water treatment showed a higher percentage of seedling emergence than the control, after 0.5 hours of soaking, and the cold water treatments were not efficient in overcoming dormancy of this species. For I. quamoclit seeds, the treatments applied had no dormancy overcome effect, damaging seed quality.

Keywords : dormancy; seeds; weeds.