Document Type : Original Article
Department of Biology, Faculty of sciences and technology, Ahmed Zabana University, Relizane, 48000, Algeria
Plant Biodiversity conservation and valorization Laboratory, Faculty of Natural and Life Sciences, Djillali-Liabes University, Sidi Bel Abbes, 22000, Algeria
The Alpha grass steppes (Stipa tenacissima) are one of the most representative steppes in the Mediterranean arid ecosystems. They are in continuous regression due to a strong climatic and anthropic pressure without forgetting the difficulties of natural regeneration. Our work is based on the conservation of this species, it consists of carrying out a comparative study of the germinative behavior of Alpha grass caryopses from the coast and the steppe (Western Algeria) under the effect of salt and water stress. For each provenance, each germination trial was conducted at the optimum temperature of 20°C and involved four batches of caryopses with 25 caryopses per batch. The effect of salt stress was tested under different salt concentrations prepared from sodium chloride: 0, 1, 2, 4, 6 and 8 g.L-1 corresponding to the molar concentrations of 0, 17.11, 34.22, 68.44, 102.66 and 136.89 mM. The effect of water stress was evaluated under different concentrations of polyethylene glycol (PEG6000) corresponding to water potentials of: - 0.04; - 0.2; - 0.4; - 0.8 and - 1.6 MPa. The results obtained showed that the salinity and the water potential directly affect the germination capacity of the caryopses of both provenances. However, coastal caryopses are more resistant to salinity than steppe caryopses with a tolerance threshold corresponding to 8g.L-1 (136.89 mM) of NaCl. Also, the coastal caryopses are much more resistant to water deficit than the steppe caryopses, they are able to germinate at a low water potential (- 1.6 Mpa).