Seed tegument: its role in the regulation of sunflower seed germination and dormancy

DEL BEL Z.; ANDRADE A.; VIGLIOCCO A.; ALEMANO S.

Buenos Aires

Congreso; XXXIII Argentinian Meeting of Plant Physiology; 2021

Sunflower seed dormancy is imposed by embryo and/or covering layers. Our objective was to elucidate the physiological role of seed tegument (ST) in interaction with embryo and pericarp in the germination and dormancy regulation. B123 and B91 cypselas were used. Germination tests were conducted in intact cypselas, without pericarp and without pericarp or ST. Hormonal determinations were performed in dry and imbibed cypselas at 0 and 33 days of dry storage. Abscisic acid (ABA), jasmonic acid (JA) and indole-3-acetic acid (IAA) were identified and quantified by Liquid Chromatography-Tandem Mass Spectrometry. B123 cypselas (dormant) without pericarp or ST raised germination up to 50%, whereas B91 cypselas (non-dormant) was not modified. ABA and JA increased in ST and decreased in embryo of B123 dry cypselas stored for 33 days. In B91, ABA decreased in ST and embryo whereas JA decreased in embryo. IAA decreased in both lines after 33 days. During imbibition, at 0 days, ABA decreased in B123 ST and remained constant until 12h in B91. JA decreased in B123 ST. In B91, JA remained constant until 12h, and increased at 18h. IAA decreased at 3h in both lines. At 33 days, ABA decreased in B123 ST at 3h, and increased subsequently. In B91, there were no changes in ABA along imbibition. JA increased in B123 ST until 3h, contrary to registered in B91. IAA did not change in both lines. Thus, the phytohormones of ST would be involved in the regulation of germination and dormancy of sunflower seeds.