Effect of storage temperature on dormancy release of sunflower (Helianthus annuus) achenes

RODRÍGUEZ, MARÍA VERÓNICA; BODRONE, MARÍA PAULA; CASTELLARI, MARÍA PAULA; BATLLA, DIEGO

SEED SCIENCE RESEARCH

CAMBRIDGE UNIV PRESS

Año: 2018 p. 1 - 11

0960-2585

Published information regarding the effect of storage temperature on dormancy alleviation ofsunflower achenes is contradictory and ambiguous. In the present study we explored the effectof temperature during dry storage on dormancy release in two sunflower genotypes, includinga commercial hybrid and an inbred line. Dry storage at 25°C consistently accelerated dormancyrelease of achenes compared with 5°C. This response fits the general pattern reportedfor dry after-ripening in seeds of many other species. Depending on the genotype and the dormancyfactor prevailing, higher temperature alleviated embryo dormancy and coat-imposeddormancy. Hormonal pathways involved in these changes were investigated at the physiologicallevel. In both genotypes, sensitivity to abscisic acid (ABA) was reduced by storage at25°C. Also, but only in one genotype, storage at 25°C reduced ABA levels upon imbibitionand increased the response to a gibberellin (GA) synthesis inhibitor and to applied GA3, comparedwith storage at 5°C; these results support the idea that temperature affects both ABAand GA metabolism and signalling pathways during after-ripening. This information willbe useful to define storage conditions for commercial sunflower achenes, and will also helpfocus future research on the underlying mechanisms of dormancy release during dry afterripeningin sunflower.