Abstract
Temperature and water potential are two important environmental factors influencing germination and subsequent seedling establishment. Seed germination requirements vary with species and with the environment in which the seeds are produced. Stipa species dominate large areas of the Eurasian zonal vegetation, but comparisons of germination requirements between Stipa species from different habitats is limited. We investigated the effects of temperature and water potential on seed germination of S. grandis, S. purpurea, and S. penicillata from habitats with low temperatures and relatively abundant rainfall (cool habitats) and S. glareosa, S. breviflora, S. gobiea, and S. bungeana from habitats with relatively high temperatures and low amount of rainfall (warm habitats). Seeds of species from cool habitats had a higher base (T b), optimal (T o), and maximum (T c) temperature than those of species from warm habitats, except for the base temperature of S. purpurea. Response of six tested Stipa species to water potential differed among species but not between habitats. Median water potential for germination was lowest for S. bungeana, S. penicillata, and S. gobiea. There was a negative correlation between hydrotime constant (θ H) and base water potential for 50% of the seeds of all species to germinate (ψ b(50)). Germination time of seven Stipa species in response to temperature and water was well predicted by thermal time and hydrotime models. Results of the present study on germination of these seven species of Stipa may provide useful suggestions for grassland restoration in different habitats.
Highlights
Seed germination is the most critical stage in the life cycle of plants, and its correct timing is essential for successful plant establishment (Baskin and Baskin, 2014; Ludewig et al, 2014)
Germination of Stipa species from the cool habitats was more tolerant to high temperature than that of species from the warm habitats
Seeds of S. purpurea from a cool habitat and those of S. breviflora from a warm habitat germinated to higher percentage at 5°C than S. glareosa, S. gobiea, and S. penicillata, while no seeds of S. grandis or S. bungeana germinated at 5°C
Summary
Seed germination is the most critical stage in the life cycle of plants, and its correct timing is essential for successful plant establishment (Baskin and Baskin, 2014; Ludewig et al, 2014). Especially temperature and soil moisture, influence seed germination, and seedling establishment (Baskin and Baskin, 2014). I.e., minimum/base (Tb), optimum (To), and maximum/ceiling (Tc) generally have been used to describe the range of temperatures over which seeds of a particular species can germinate (Bewley et al, 2013). These cardinal temperatures for germination match germination timing to favorable conditions for subsequent seedling growth and development (Alvarado and Bradford, 2002), helping predict their current/future spatial distribution (Dürr et al, 2015). Seeds of Fabaceae species from the Qing-Tibetan Plateau, an area with low temperatures and relatively abundant rainfall, had a lower base and a lower optimal temperature for germination than those from the Alax Desert, an area with high summer temperatures and low amount of rainfall (Hu et al, 2015)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
