Effect of seed priming on germination, total dry matter and some physiological traits in two Alhagi species (Alhagi maurorum Esfahan ecotype and A. graecorum Khuzestan ecotype) under saline conditions

Materials and methods Two separate experiments was conducted to investigate seed priming (non-priming, hydro priming, hormonal priming with 50 ppm gibberellin and hydro priming + hormonal priming with 50 ppm gibberellin) and different salinity levels (urban water source with EC=0.96 dS.m-1, 8 and 16 dS.m-1 using seawater Persian Gulf) on seed germination, dry matter and some physiological response of Alhagi species (Alhagi maurorum Esfahan ecotype and A. graecorum Khuzestan ecotype). The first experiment (seed germination) was carried on in the petri dish culture and second experiment (in the pot) at the field conditions was performed under split factorial experiments were conducted based on a randomized complete block design with four replications in Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University (Ahwaz, Iran) during 2020-21. Meanwhile, during research, after calculating of the leaching fraction, EC of the root environment was controlled three times with an interval of one month by preparing a saturated extract from the pot bed and only in the third sampling was performed a leaching in the treatments of 16 dS m-1, with a salinity level lower than the studied treatment (8 ds.m-1). Results and discussion The results showed a significant effect of salinity × priming × species interaction on all studied traits except for transpiration rate, Na and K content. In the case of transpiration rate, only the effects of salinity and priming were significant. Mean comparison results showed that the highest amount of seed germination, total dry matter, net photosynthesis rate, sub-stomata CO2 concentration, photosynthetic water use efficiency and number of leaves per plant in A. graecorum Khuzestan ecotype under Non-salinity stress and Hydro priming + Hormonal priming with 50 ppm gibberellin treatment (increased by 29.1, 1.52, 26.8, 98.7, 15.6 and 38.8 percent respectively compared to the Non-priming and Non-salinity stress treatment in the A. maurorum Esfahan ecotype). The highest level of mesophilic conductance was observed in A. graecorum Khuzestan ecotype under Non-priming and 8 dS.m-1 salinity stress treatment (with an average of 0.492 mmol CO2.m-2.s-1). Conclusion In this experiment, results showed significant differences in total dry weight, net photosynthesis rate, transpiration rate, sub-stomata CO2 concentration, mesophyll conductance and photosynthetic water use efficiency between two Alhagi species at different salinity conditions using Persian Gulf water. Indeed, dry matter and photosynthesis traits in both Alhagi species responded negatively to increasing salinity levels and increasing of salinity up to, 8 dS m-1 induce the loss in physiological responses. Among the priming treatments, the hydro priming + hormonal priming with 50 ppm gibberellin showed a more favorable condition in the two Alhagi species in terms of the studied traits. Finally, in cultivation and development of Alhagi species for breeding programs in saline coastal lands and for the restoration of pastures, according to the results, A. graecorum Khuzestan ecotype under the combined treatment as hydro priming + hormonal priming with 50 ppm gibberellin, recommended for high production.