Seed germination requirements of relictic and broadly-distributed populations of Chaerophyllum aureum (Apiaceae): connecting ecophysiology and genetic identity

Abstract

The main goal of this work was to relate the germinative ecology and genetic variability of Chaerolhyllum aureum L., anApiaceae plant with dormant, underdeveloped embryos at the time of seed dispersal. We compared the seed germination physiologytraits between a relictic geographically isolated Mediterranean population (Iberian System; central Spain) and a population locatedin the main, colder Atlantic Alpine core (Pyrenees; northern Spain). We analyzed both populations’ genetic identity in parallel on thebasis of ISSR–PCR analyses. Stratification, gibberellin treatment, and seed storage tests showed that C. aureum seeds have deep complexmorphophysiological dormancy. The Iberian System population seeds required shorter cold stratification than the Pyrenees populationseeds (16 vs. 20 weeks) to germinate. The genetic analyses suggested closer similarity between Iberian System individuals and thosefrom the Pyrenees requiring shorter cold periods to germinate. Our findings denote a consistent parallelism between germinationphysiology and genetic identity. The records from these germination and genetic analyses suggested selective pressure due to the climatedifferences between the two geographical regions. Thus, the individuals in the Iberian System population would have been selected fromthe original pool to a shorter cold-stratification requiring ecotype.