Germination and Seedling Growth Responses of Zygophyllum fabago, Salsola kali L. and Atriplex canescens to PEG-Induced Drought Stress

In arid and semi-arid regions, planting drought-tolerant species is the most useful strategy in the reclamation of degraded soils. In the present study, we evaluated the effect of simulated drought by polyethylene glycol (PEG-6000) on seed germination and seedling growth of three desert plants such as Atriplex canescens, Salsola kali and Zygophyllum fabago. Seeds were subjected to water stress to drought stress by PEG at five stress levels (0, -1, -4, -8, -12, -14 bars). Germination of Z. fabago was completely inhibited at an osmotic potential of -8, -10 and -12 bars and the germination of A. canescens was inhibited only at -14 bar. In contrast, S. kali responded positively to high levels of stress and our results showed the highest final germination percent (71.75, 54 and 18.25%) under three-drought stress -8, -12 and -14 bars, respectively. In addition, increasing PEG concentration adversely affected the germination rate and seedling vigor index as well as the root and shoot length of species. Under high stress levels, S. kali achieved a higher germination rate and seedling vigor index compared to Z. fabago and A. canescens. Among species, S. kali was the only one able to develop roots and shoots at -14 bar. Therefore, S. kali could be considered as a promising plant for the rehabilitation of degraded soils at risk of desertification.