Changes in sensitivity to alternating temperatures in relation to dormancy loss in Polygonum aviculare l. seeds. development of a thermal time predictive model

VIRGINIA VERGES; DIEGO BATLLA; ROBERTO LUIS BENECH-ARNOLD

Salamanca, España

Workshop; Seventh International Workshop on Seeds; 2002

International Seed Science Society

Changes in sensitivity to alternating TEMPERATURES in RELATION to DORMANCY loss In Polygonum aviculare L. SEEDS. DEVELOPMENT OF A THERMAL TIME PREDICTIVE MODEL. Virginia Verges, Diego Batlla and Roberto Benech-Arnold, Department of Plant Production, Faculty of Agronomy, University of Buenos Aires, Av. San Martín 4453, C1417DSE-Buenos Aires, Argentina.   An increase in the sensitivity to alternating temperatures cycles was observed as the seed population was released from dormancy. The rate at which this process occurred was dependent on the temperature at which seeds after-ripened. Response curves for seeds after-ripened at different temperatures were related to a thermal after-ripening time index. Using a Gompertz function, response-curves (i. e. proportion of the population released from dormancy as a function of the number of cycles of alternating temperature) for seeds after-ripened at different temperatures but which had accumulated an equal thermal time were determined. Therefore, functions describing changes in the parameters that characterised the Gompertz function in relation to thermal after-ripening time were derived. These equations permit the prediction of the fraction of the seed population that will response to the effect of temperature fluctuation in relation to seed dormancy status.   Preferred sessions: (First choice) Seed germination and dormancy (Modelling germination and dormancy) or Seed ecology (Ecology of germination). Poster presentation.