Univrsity of Tehran Press Iranian Journal of Field Crop Science 2008-4811 56 3 2025 09 23 Ecological Responses of Halophyte Atriplex verucifera to Salinity and Temperature Conditions during Seed Germination and Seedling Growth Stages Ecological Responses of Halophyte Atriplex verucifera to Salinity and Temperature Conditions during Seed Germination and Seedling Growth Stages 67 81 105498 10.22059/ijfcs.2025.379171.655090 FA Fatemeh Divargar Agronomy and Plant Breeding Department , College of Agriculture and Natural Resources, University of Tehran. Karaj. Iran Farzad Sharifzadeh Agronomy and Plant Breeding Department , College of Agriculture and Natural Resources, University of Tehran. Karaj. Iran Houshang Alizadeh Agronomy and Plant Breeding Department , College of Agriculture and Natural Resources, University of Tehran. Karaj. Iran 0000-0001-8138-0786 Journal Article 2024 08 07 Introduction. The halophyte Atriplex verucifera is a valuable forage species that is also cultivated for other purposes such as rehabilitation of saline ecosystems, phytoremediation, and soil erosion control too. The germination process is a crucial stage in the lifespan of a plant that is delayed or inhibited in the face of salinity, osmotic, and extreme temperature conditions. On this subject, the performance of seed germination directly determines the successful seedling establishment and dynamics of plant communities. Hence, this study aimed to characterize the biological parameters of cardinal temperatures (Tb, To1, To2, and Tc) and to quantify the effect of NaCl-induced osmotic stress in the physiological parameters related to seed quality. Materials and Methods. Seeds were surface sterilized by soaking in 2.5% sodium hypochlorite for 30 seconds (s) followed by 20 s in 30% alcohol, and then thoroughly rinsed in the sterile distilled water for several 60 s. Firstly, to determine cardinal temperatures, seed germination was conducted at wide range temperature from 1°C to 40°C at 5°C intervals in three replicates. In per replication, the germination test of 50 seeds was performed on top of two Whatman paper in a glassy petri dish including 8 ml of autoclaved distilled water. To evaluate the interaction effects of salinity and chilling conditions, germination of seeds was performed at the sodium chloride (NaCl) concentrations [Ψ] of zero (control), - 0.4, - 0.8, - 1.2, - 1.6, - 2, - 2.4, - 2.8, and - 3.4 MPa and a set of the wide range of constant temperatures [T] (1, 5, 10, 15, 20, and 25°C) as factorial completely randomized design. Seeds were germinated in glass Petri dishes (9 cm diameter) contained 8 ml of corresponding osmotic solutions without filter paper. The germination test was conducted in the incubator (Memmert GmbH + Co. KG, incubator, Germany, ± 0.5 °C precision) for 12 d. Results and Discussion. Based on the dent-like model, the value of cardinal temperatures was estimated 0.031 °C for Tb, 15.36 °C for TO1, 35.2 °C for TO2, and 40.84 °C for Tc. Noticeably, the results of this study demonstrated that the high value of salinity tolerance in this plant during seed germination was observed at the temperature of 15 °C. At the temperature of 15 °C, the value of germination percentage at salinity levels of -2.8 and -3.2 MPa was 60% and 20%, respectively. Furthermore, at the high salinity level of -2.8 MPa, the normal seedling growth (by 20%) was only observed at the temperature of 15 °C compared to all examined temperatures. By increasing the temperature to 25 °C, the salinity tolerance in early growth stages was significantly declined compared with temperature of 15 °C, indicating the influence of T on salinity tolerance during germination. Conclusion. The predicted lower value of base temperature (Tb) indicate a higher tolerance to chilling stress during seed germination, especially when they are exposed to salinity stress. The findings can be useful to identify the responses of seed ecology and then to determine the germination niche of this halophyte plant for its successful establishment in saline and cold ecosystems. However, the estimated of biological parameters (cardinal temperatures) and salinity response during germination suggest the possible that Atriplex verucifera is a tolerance halophyte to wide range of temperatures and osmotic stress. Introduction. The halophyte Atriplex verucifera is a valuable forage species that is also cultivated for other purposes such as rehabilitation of saline ecosystems, phytoremediation, and soil erosion control too. The germination process is a crucial stage in the lifespan of a plant that is delayed or inhibited in the face of salinity, osmotic, and extreme temperature conditions. On this subject, the performance of seed germination directly determines the successful seedling establishment and dynamics of plant communities. Hence, this study aimed to characterize the biological parameters of cardinal temperatures (Tb, To1, To2, and Tc) and to quantify the effect of NaCl-induced osmotic stress in the physiological parameters related to seed quality. Materials and Methods. Seeds were surface sterilized by soaking in 2.5% sodium hypochlorite for 30 seconds (s) followed by 20 s in 30% alcohol, and then thoroughly rinsed in the sterile distilled water for several 60 s. Firstly, to determine cardinal temperatures, seed germination was conducted at wide range temperature from 1°C to 40°C at 5°C intervals in three replicates. In per replication, the germination test of 50 seeds was performed on top of two Whatman paper in a glassy petri dish including 8 ml of autoclaved distilled water. To evaluate the interaction effects of salinity and chilling conditions, germination of seeds was performed at the sodium chloride (NaCl) concentrations [Ψ] of zero (control), - 0.4, - 0.8, - 1.2, - 1.6, - 2, - 2.4, - 2.8, and - 3.4 MPa and a set of the wide range of constant temperatures [T] (1, 5, 10, 15, 20, and 25°C) as factorial completely randomized design. Seeds were germinated in glass Petri dishes (9 cm diameter) contained 8 ml of corresponding osmotic solutions without filter paper. The germination test was conducted in the incubator (Memmert GmbH + Co. KG, incubator, Germany, ± 0.5 °C precision) for 12 d. Results and Discussion. Based on the dent-like model, the value of cardinal temperatures was estimated 0.031 °C for Tb, 15.36 °C for TO1, 35.2 °C for TO2, and 40.84 °C for Tc. Noticeably, the results of this study demonstrated that the high value of salinity tolerance in this plant during seed germination was observed at the temperature of 15 °C. At the temperature of 15 °C, the value of germination percentage at salinity levels of -2.8 and -3.2 MPa was 60% and 20%, respectively. Furthermore, at the high salinity level of -2.8 MPa, the normal seedling growth (by 20%) was only observed at the temperature of 15 °C compared to all examined temperatures. By increasing the temperature to 25 °C, the salinity tolerance in early growth stages was significantly declined compared with temperature of 15 °C, indicating the influence of T on salinity tolerance during germination. Conclusion. The predicted lower value of base temperature (Tb) indicate a higher tolerance to chilling stress during seed germination, especially when they are exposed to salinity stress. The findings can be useful to identify the responses of seed ecology and then to determine the germination niche of this halophyte plant for its successful establishment in saline and cold ecosystems. However, the estimated of biological parameters (cardinal temperatures) and salinity response during germination suggest the possible that Atriplex verucifera is a tolerance halophyte to wide range of temperatures and osmotic stress.

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