Germination traits of the cypselas on the native Hyalis argentea (Asteraceae)

Abstract

The germination requirement of native species are key factors in the ecological restoration of degraded ecosystem. A variety of plant seeds are affected by dormancy. Therefore, the knowladge of processes and enviromental factors that control germination can aid in decision making on how to use species for restoration. This study evaluated the germination responses of Hyalis argentea cypselas to different photoperiods conditions. The existance or not of a germination inhibitor located in the pappus of the cypselas was also investigate. Cypselas were gathered randomly from a plant population in the semiarid Pampa. They were exposed to four germination treatment during 18 days at 25ºC under different light regimens: (i)darkness and (ii) long or short photoperiods (this latter treatment using cypselas with-iii-and without-iv-pappus). The porcentage of germination was 14% for long periods and an average of 77% for darkness and short periods, with and without pappus. Our results suggest that Hyalis aregentea is a non-dormant specie that germinates during autum, taking advantage of soil resources over other species that germinate during the spring in the Semiarid Pampa region.