Maternal source affects seed germination of a rare Arabian desert species (Astragalus sieberi)

Abstract

Understanding variation of seed germination in wild populations can assist restoration projects through improved seed source selection. Recruitment of artificially distributed seed can be improved by selecting for suitable dormancy and germination characteristics. We investigated seed germination and emergence responses of three Astragalus sieberi DC. (Fabaceae) populations (Abdali, Liya, and Salmi) to in situ storage for five months at depths of 0 and 5 cm, pre-sowing hydration for 12 and 24 hours, and chemical scarification with concentrated sulfuric acid for 5, 10, and 15 min. The germination percentage was low for freshly collected seed (<3%) from Abdali and Salmi, though in situ storage partially enhanced germination. Pre-sowing hydration did not affect seedling emergence, but acid scarification effectively broke seed dormancy. The longest scarification treatment of 15 min produced the greatest seedling emergence, though populations responded differently. Our results indicate that selection of maternal, native seed sources can improve revegetation projects in desert areas. Knowledge of inter-population variation can improve the understanding of the mechanisms regulating seed germination, thus optimizing restoration projects by selecting optimal seed sources.