Leaf analyses of gypsophile flora from Sicily

A large number of gypsum outcrops are widespread in Sicily, and a peculiar flora is associated to it (Brullo et al., 1989). In fact, gypsum habitats constitute areas with high plant richness and rarity, from the botanical view. Elsewhere in the Mediterranean Basin these ecosystems are considered as priority for the nature conservation by the European Habitats Directive, and included in the Gypsum steppes (Gypsophiletalia) 1520* priority habitat.Furthermore, studies have revealed that some specific physiological mechanisms in gypsophile plants could perform as an important part of plant adaptation to live on gypsum (Merlo et al., 2001), and that chemical factors (high Ca and S concentrations; low cation-exchange capacity) may control community structure on highly gypseous substrates (Bolukbasi et al., 2015).Chemical composition of leaves from three Italian gypsum endemics (Brassica villosa subsp. tinei (Lojac.) Raimondo & Mazzola; Erysimum metlesicsii Polatschek; Gypsohila arrostii Guss.) and five Mediterranean distributed gypsophiles (Chaenorrhinum exile (Coss. & Kralik) Lange; Diplotaxis harra subsp. crassifolia (Raf.) Maire; Sedum gypsicola Boiss. & Reut.; Sedum ochroleucum Chaix; Matthiola fruticulosa (L.) Maire)) growing in Sicily have been compared, in order to reveal any ecological strategy as stress-tolerant on them. The capacity of accumulation in leaves of Ca and S (and other inorganic elements as Mg) is a generalized strategy of characteristic gypsophytes. Commonly, the highest contents in S were present in some Brassicaceae and G. arrostii. This species (and generally, Gypsophila genus), along with the studied species of Sedum genus, presented both the highest contents in Ca, and leaf succulence. These facts suggest their ecological strategy for stress-tolerant (due to the Ca excess) is to be accumulators; regardless their distribution patterns (Bolukbasi et al., 2015). Moreover, all the studied Cruciferae species (M. fruticulosa, D. harra and B. villosa) accumulated more than 2% Ni content (in some cases, up to 4%) and Sr. Accumulation of inorganic elements is common in this family in different types of habitats. Finally, the strong correlation, in almost all species studied, between Al and Fe contents is remarkable. Probably because of Al acidifies the environment, what promotes mobility of Fe, and other elements as P.Such analyses, along with further gypsum flora studies would be useful as evidences to support a greater preservation of these interesting natural areas in Sicily.