SEED-GERMINATION OF GYPSOPHYTES AND GYPSOVAGS IN SEMIARID CENTRAL SPAIN

Seed germination under controlled conditions was studied for six restr icted gypsophytes and five gypsovags, three with calcareous preference s and two of salt optima, most of them local endemics of the central I berian Peninsula. The main aim of this study can be briefly summarized as: is germination of these plants one of differential factors acting on the high biological selective availability of gypsum soils or are these plants similar at this biological stage to surrounding plants, n ot edaphisms? Our results suggest that both gypsophytes and gypsovags present the typical germination strategies of semiarid Mediterranean p lants: efficient responses at low temperatures, multipurpose strategie s and heteromorphism within and among seed populations, and clinal var iation in seed dormancy. These two types of edaphisms do not differ si gnificantly in their germinability behaviour and the detected variabil ity can be easily explained by the taxonomic groups to which these pla nts belong. It seems patent that gypsum has acted interactively at the seedling and mature stages of these plants, but it has not forced dif ferent strategies at the germination stage. (C) 1997 Academic Press Li mited.