Does gypsum influence seed germination?

Abstract

Flora inhabiting gypsum outcrops in arid environments shows a high level of specialization. However, the processes involved are still unclear, specifically at the key stage of germination. Here, to assess whether gypsum could chemically influence seed germination, we tested the germination of species according to 3 functional groups: gypsophiles, gypsovags, and calcicoles. A total of 24 taxa were selected, all occurring in gypsum and limestone substrates, under a semiarid and dry Mediterranean climate. Three levels of gypsum (CaSO 4 •2H 2 O) solution (low = 0.5 g/L, medium = 1 g/L, and high = 2.4 g/L) and 1 control treatment of distilled water were tested. Results depended on the particular species rather than on the functional group. We found that gypsum favored germination in some species (Lepidium subulatum L. and Gypsophila struthium L.), whereas significant negative effects appeared for only 1 species (Rosmarinus officinalis L.). In contrast, most of the species studied responded neutrally to gypsum solutions. Our results suggest that chemical features of gypsum could offer an advantage at the germination stage for certain species, rather than posing a constraint for seed germination.

Unravelling the mechanisms for plant survival on gypsum soils: an analysis of the chemical composition of gypsum plants from Turkey

“…; Cañadas et al . ). Previous studies showed that gypsophiles have higher S, Ca and total ash content than gypsovags (Duvigneaud & Denaeyer‐De Smet ; Duvigneaud ; Boukhris & Lossaint , ; Palacio et al .…”

Do soil features condition seed germination of gypsum plants? An analysis of the effect of different natural soils

“…We hypothesized that (1) the germination of gypsophiles would be higher in natural gypseous soil and lower in the acidic soil; (2) gypsovags would show similar germination on soil with or without gypsum; and (3) owing to the similar germination responses observed in gypsophiles from the Iberian Peninsula and the Chihuahuan Desert (e.g. Cañadas et al, 2014;Secor and Farhadnejad, 1978), we expect the aforementioned trends would hold true regardless of geographic origin.…”

“…Some gypsum endemic species have also been shown to have a higher ability than co-occurring gypsovags to surpass the hard physical crust typical of gypsum soils at the seedling stage (Romão and Escudero, 2005). The distribution of plants on gypsum soils could also be linked to a differential ability to germinate on gypsum (Romão and Escudero, 2005), since calcium and gypsum concentration can affect seed germination, also in gypsophile species (Anderson, 1982; Cañadas et al, 2014; Merlo et al, 1997; Secor and Farhadnejad, 1978).…”

“…Soil pH differences also may lead to substantial changes in seed germination (Pierce et al, 1999), and some plant species have been shown to germinate preferentially in a specific pH range (Ma and Liang, 2007). Some widely distributed gypsophile species from Spain and the Chihuahuan Desert increased their germinating ability when treated with a gypsum saturated solution (Cañadas et al, 2014; Merlo et al, 1997; Secor and Farhadnejad, 1978), which some authors attributed to the effect of Ca (Merlo et al, 1997). Seeds of gypsum endemic species may be adapted to germinate in the stressful conditions of these soils, but experimental evidence on the effect of field gypseous soils is lacking (but see Romão and Escudero, 2005).…”

Is salinity the main ecologic factor that shapes the distribution of two endemic Mediterranean plant species of the genus Gypsophila?

“…struthium is one of the most abundant gypsophytes in Spain, and is exclusive of gypsum soils. It is specifically adapted to gypsum, which even has a positive effect on the germination of its seeds (Cañadas et al 2013). This species is endemic in the SE Iberian Peninsula, with a wide distribution in the C, E and S, in the Murcian-Almerian, Balearic-Catalonian-Provençal, Baetic and Mediterranean Central Iberian biogeographic provinces.…”