Document Type : Original Article

Authors

• Farzaneh Amirikia ¹
• Majid Nabipour ²
• Masoumeh Farzaneh ³

¹ Ph.D. Student of Agrotechnology, Department of Production Engineering and Plant Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

² Professor, Department of Production Engineering and Plant Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

³ Assistant Professor, Department of Production Engineering and Plant Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract

Introduction
The researchers have been forcing to investigate and find an edible alternative high forage quality plant that has a well-tolerated instinct against adverse environmental conditions. Alhagi, a genus of Fabaceae is one of the most important halophyte plants in the world, as an industrial forage product used in the near future, medicinal production and pharmaceutical use. There are many reasonable that Alhagi plants productivity and satisfactory yield requires good seed germination and seedling establishment. Generally, germination and seedling establishment is the most decisive stage of Alhagi plants life cycle to environmental stress. Moderate to severe salinity stress is main abiotic causes of Alhagi plants productivity loss at the seedling growth stage. High accumulation of Na⁺ and Cl^- ions cause various negative influences that impact Alhagi production, such as delays in the response of the plant to environmental conditions, retardation of germination, growth and development, inhibition of enzymatic activities and accumulation of some compatible osmolyte. In addition, to the salinity stress, the seed germination, seedling establishment and total dry matter production in Alhagi plants occurs depends on a seed priming and type of species. However, few research studies have so far investigated the impact of different seed priming on the total dry matter production as well as some physiological responses in Alhagi species.
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.

Keywords

• Halophyte plant
• Hormone
• Net photosynthesis rate
• Priming
• Transpiration rate

Main Subjects

• Physiology of crops under stress conditions