HORMONAL CHARACTERIZATION OF DORMANCY CYCLING IN POLYGONUM AVICULARE SEEDS

LASPINA N.; BENECH ARNOLD R.L.

Congreso; 12 th Conference of the International Society for Seed Science; 2017

ISSS

HORMONAL CHARACTERIZATION OF DORMANCY CYCLING IN POLYGONUM AVICULARE SEEDSLapina, N. and Benech-Arnold, R.IFEVA, Universidad de Buenos Aires, CONICET, Facultad de Agronomía, Buenos Aires, ArgentinaContact: Roberto Benech-Arnold, benech@agro.uba.arPolygonum aviculare, an important weed species, forms stable seed banks cycling between dormantand non-dormant states according to seasonal changes. Seeds of this species have been widelystudied for the last few years because of its dormancy behavior. Available models developed for seeddormancy in P. aviculare allowed us to generate seed populations with different dormancy levelsproviding an advantage for dormancy study over other species. The objective of this work was tocharacterize the mechanism(s) involved in the dynamics of primary dormancy release (PD) andsecondary dormancy induction (SD) in P. aviculare seeds. Quantification of endogenous abscisic acid(ABA), seed incubation at different concentrations of exogenous ABA and qPCR for sequences relatedto ABA metabolism (PaNCED and PaABA8OHase) were performed at different times in a cycle fromseeds with PD and different stages during the release from primary dormancy to a state of lowdormancy (LD) and finally during re-induction to secondary dormancy (SD). We showed that primarydormancy release in P. aviculare was characterized by a loss of sensitivity to exogenous ABA and thatsensitivity was recovered when re-induced into secondary dormancy. Endogenous ABA andsequences related to ABA metabolism quantification showed a decrease from PD to LD that remainedconstant during SD induction. We showed that the mentioned decrease in ABA content during primarydormancy release was not associated to dormancy mechanism as this decrease occurred early inincubated PD seeds with zero germination. We concluded that sensitivity to ABA instead ofendogenous ABA content would be one of the main mechanisms controlling loss and induction ofdormancy in P. aviculare seeds.