Variations in seed germination behavior of Phleum hirsutum subsp. ambiguum and possible applications in semi-natural grassland restoration

Phleum hirsutum Honck. subsp. ambiguum (Ten.) Tzvelev is an important component of the vegetation of some semi-natural grassland habitats of central and southern Italy and especially of those referring to the 6210^* habitat (Directive 92/43/EEC). Seeds of this species are required for the execution of restoration works concerning this habitat. Therefore, the recovery and the study of autochthonous germplasm are needed. This study focused on the intra-specific variations in seed mass and size and in seed germination behavior in this species since the knowledge of these aspects can be very useful in the planning of restoration projects. The present research evidenced significant differences in mean seed mass and size in the populations studied that were correlated to the precipitation values of their collection sites. Studied seeds are able to germinate under a wide range of temperatures. They reached their maximum germination between 5 and 25°C and are capable of germination even at 30°C but with a remarkable reduction in germination percentage. Temperature was found to strongly influence germination, especially in terms of the speed. Light was found to enhance germination in almost all the populations studied while the removal of outer covering structures was found to be of no effect.