Effects of photoperiod, thermoperiod, and salt stress on Gymnocarpos decandrus seeds: potential implications in restoration ecology activities

Abstract

Gymnocarpos decandrus Forssk. (Caryophyllaceae) is a perennial plant widely used for its ability to protect the soil from erosion. The aim of this study was to evaluate the effects of salt stress on its seed germination, with the potential objective to sow seeds instead of planting adult individuals in salt-damaged areas, which would greatly reduce the economic costs of ecological restoration activities. Germination tests were conducted under two photoperiods and three thermoperiods, and with several concentrations of NaCl. The ability of seeds to recover their germinability after salt exposure was also evaluated. The highest rates of germination occurred at 20/30 °C in the light, but no seed germinated in the salt substrate. When exposed to NaCl, only a few seeds (no more than 20%) recovered their germinability and only at the lowest salinity, indicating that this species is highly glycophytic. The inability of its seeds to germinate in saline soils or to successfully recover from exposure to NaCl shows that G. decandrus may be used in rehabilitation programs of degraded lands in arid regions, but only when planting adult plants. Our results will help conservation biologists or people involved in ecological restoration activities to avoid the economic waste associated with unsuccessful sowing of G. decandrus seeds in saline soils.