Shahrzad Ghabeli, Hamidreza Ebrahimi, Hamidreza Miri, Barmak Jafari Haghighi, Abdolreza Jafari,
Volume 12, Issue 2 (10-2025)
Abstract
Objective: The objective of this research was to evaluate the effect of temperature, salinity, and seed priming on germination and to determine cardinal germination temperatures (i.e., base, optimum, and maximum) of Camelina seeds.
Method: Experimental treatments included different levels of seed priming (control, hydropriming, priming with gibberellic acid, and brassinosteroid at 50 ppm), salinity (0, 100, and 200 mM), and different temperatures (5, 10, 15, 20, 25, 30, 35, and 40°C). To estimate cardinal temperatures, three nonlinear regression models (dent-like, segmented, and beta) were fitted, and their accuracy was evaluated using RMSE, CV, R², and SE criteria.
Results: The results showed that Camelina seed germination was significantly affected by the interaction of temperature, salinity, and priming treatments, and none of these factors could be interpreted independently. The highest germination percentage and rate were obtained at 20°C under non-saline conditions, particularly with the application of gibberellic acid and brassinosteroid at 50 ppm; whereas the combination of high temperatures (especially 35°C) and 200 mM salinity caused a severe reduction or complete inhibition of germination. Hormonal priming, in addition to increasing germination percentage, reduced the time to 50% germination, thereby increasing germination rate, decreasing base temperature, and improving the thermal tolerance range. Among the three models evaluated, based on RMSE, CV, R², and SE criteria, the segmented and dent-like models were the most suitable for estimating the cardinal temperatures of Camelina. The results also showed that the most effective priming treatment was priming with brassinosteroid.
Conclusion: The use of priming, especially with brassinosteroid and gibberellic acid, can be recommended as an effective strategy to improve Camelina seed establishment under salinity stress and temperature fluctuations. The use of nonlinear regression models, including dent-like, segmented, and beta models, can be effectively used to quantify the response of Camelina seed germination to temperature, salinity, and seed priming. Therefore, by utilizing the output of these models across different temperatures, it is possible to predict the germination rate under various priming treatments and salinity levels.
Highlights:
- Assessing the combined effects of temperature, salinity, and priming on Camelina seed germination.
- Quantifying the impact of seed priming on cardinal temperatures of Camelina under salinity stress.
- Comparing and selecting the superior nonlinear model (dent-like and segmented) for estimating Camelina cardinal temperatures under salinity stress and priming.
