Document Type : Research Paper

Authors

• Soraya Ghassemi ¹
• Gholam Akbari ²
• elias soltani ³
• Maryam Mansori ¹

¹ , Department of Agronomy Sciences and Plant Breeding, Faculty of Agricultural Technology, University of Tehran, Pakdasht, Iran

² Associate Professor, Department of Agronomy and Plant Breeding Sciences, College of Aburaihan, University of Tehran, Pakdasht, Iran

³ Department of Agronomy Sciences and Plant Breeding, College of Aburaihan, University of Tehran, Pakdasht, Iran

Abstract

Objective: Drought and soil salinity are major constraints limiting crop performance and global productivity. Niger seed (Guizotia abyssinica), an oilseed-forage species in the Asteraceae, exhibits rapid life cycle and notable drought and salinity tolerance, making it a candidate for marginal environments. This study evaluated the ecophysiological responses of Niger seed germination under controlled drought and salinity stress to inform potential cultivation in stress-prone regions.
Methods: Two controlled-laboratory experiments were conducted in a completely randomized design with four replications. Drought stress was simulated with polyethylene glycol 6000 (PEG-6000) at six osmotic potentials: 0 (control), −0.2, −0.4, −0.6, −0.8, and −1.0 MPa. Salinity stress was imposed using NaCl at five concentrations: 0 (control), 50, 100, 150, and 200 mM. Germination dynamics were quantified using maximum germination percentage (Gmax), time to 10% germination (R10), and time to 50% germination (R50) as key metrics of seed vigor and germination pace under stress.
Results: Under drought, Gmax peaked at 95% at −0.2 MPa and declined to 6% at −1.0 MPa. R10 was highest in the control (mean ≈6.5 seeds·day⁻¹) and dropped to 0.04 seeds·day⁻¹ at −1.0 MPa. R50 reached a maximum of 1.3 seeds·day⁻¹ in control, with no germination at –1.0 MPa. Under salinity, Gmax decreased from 98% (control) to 58% at 200 mM NaCl. R10 ranged from 1.8 seeds·day⁻¹ (control) to 0.44 at 200 mM NaCl, and R50 declined from 1.62 seeds·day⁻¹ (control) to 0.09 seeds·day⁻¹ at 200 mM NaCl.
Conclusions: Niger seed germination is sensitive to both drought and salinity, particularly under severe stress, but shows resilience under low to moderate stress levels where germination percentage and speed are less affected. These findings suggest Niger seed has potential as an alternative crop in semi-arid regions with limited water and moderately saline soils. Further research could optimize management strategies for stress-prone environments

Keywords

• Abiotic Stres
• Germination Indices
• Medicinal Plant
• Osmotic Potential