Longevity of seeds of Wedelia glauca (Ortega) O. Hoffm. Ex Hicken buried in the ground and conserved in the lkaboratory

SOBRERO M. T, CHAILA S, FERNÁNDEZ O, SABBATINI M R

Tafí del Valle, Tucumán, Argentina

Congreso; XXV Annual Scientific Meeting Tucuman Biology Association; 2009

Biocell 33 (2), 2009 15 LONGEVITY OF SEEDS OF Wedelia glauca  (Ortega) O. Hoffm. Ex Hicken BURIED IN THE GROUND AND CONSERVED IN THE LABORATORY. Sobrero M. T., Cahila S, Sabbatini N. R, Fernández O. A. Fac. de Agronomía y Agroindustrias, UNSE, Avda. Belgrano 1912, 4200 S. del Estero, E-mail: marite@unse.edu.ar   Wedelia glauca is a most important weed for many crops in north-western Argentina. Knowledge of buried seed survival in the field gives important information about persistence and degradation patterns and help to develop management practices. Studies were made to determine the longevity of: a) seeds buried in the ground; b) seeds conserved in the laboratory. In the first case bags with 50 fruits  were places 20 cm deep. Four were collected after 1½, 3, 6, 12, 18 months. In the laboratory the fruit state was observed. For germination power seeds were placed in a chamber at 20º C for 25 days. In the second case , mature seeds harvested from 1991 to 2007 were conserved in the laboratory and kept at 20º C. Four replications of 25 seeds per year and origin were made. Germination percentage of buried seeds decreased and became null at 12 and 18 months. Buried seeds preserved viability for less than one year. In the laboratory, fruits from 1991 to 2002 did not germinate; from 2003 had 17% germination power; from 2004, 48%; from 2005, 70%; from 2006, 71,5%, and from 2007, 90%. In the field the lost of germination  power was 100% at 12 months. His is because the fruits conserved in the laboratory do not suffer deep dehydratation or metabolism interruption.  W. glauca buried fruits  lost germination power after one year while those in the laboratory preserver germination capacity up to five years.