Showing 263 results for Type of Study: Research
Negin Moein, Rayhaneh Amooaghaie,
Volume 12, Issue 2 (10-2025)
Abstract
Objective: This research aimed to investigate the effect of treatments such as seed scarification and nitrogenous compounds on seed dormancy breaking, germination indices, and seedling growth of Astragalus adscendens Boiss. & Hausskn.
Method: In the first experiment of this study, the effect of soaking seeds in 95°C boiling water for 5, 10, and 20 minutes, as well as scarification with a razor, on seed germination was investigated based on a completely randomized design. In the second experiment, the effect of scarification with a 50% solution of various chemical compounds (water, hydrochloric acid, sulfuric acid, acetic acid, and hydrogen peroxide) for different durations (2, 5, and 10 minutes) on seed dormancy breaking was evaluated. In the third experiment, the interactive effect of seed scarification with a razor or sulfuric acid and various nitrogenous compounds on seed dormancy breaking and seedling growth of A. adscendens was investigated.
Results: The results of the first and second experiments showed that intact control seeds had only about 20% germination, but 10 minutes of treatment with boiling water and razor scarification increased germination to 60.57% and 70%, respectively. The best values for mean daily germination, peak value, and germination value were obtained with 5 minutes of sulfuric acid treatment, followed by 5 minutes in hydrochloric acid. The results of the third experiment showed that treatment with thiourea, potassium nitrate, and sodium nitroprusside had no significant effect on the germination of intact A. adscendens seeds, but significantly increased the percentage and rate of germination of seeds scarified with a razor or sulfuric acid, as well as the root and shoot length of seedlings. The greatest effect on germination percentage was achieved with the application of sodium nitroprusside (as a nitric oxide-producing compound) on seeds scarified with a razor (90%) or sulfuric acid (79%). Also, potassium nitrate caused the greatest increase in the root length of seedlings from seeds scarified with a razor or sulfuric acid, and the highest shoot length was obtained with the application of sodium nitroprusside.
Conclusion: The obtained results indicate that A. adscendens seeds have both physical and physiological dormancy, and scarification with a razor followed by treatment with sodium nitroprusside is suitable for breaking this dual dormancy.
Highlights
- Sulfuric acid or razor scarification breaks physical dormancy more effectively than boiling water in A. adscendens.
- For the first time, scarification + nitrogenous compounds overcame combined dormancy in A. adscendens.
- Razor scarification followed by sodium nitroprusside was the most effective treatment.
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.
Akram Oraki, Ehsan Shahbazi, Keramatollah Saeidi, Fariba Rafiei,
Volume 12, Issue 2 (10-2025)
Abstract
Objective: This study evaluated the effects of polyethylene glycol (PEG)-induced drought stress on germination traits, seedling growth, and seed vigor across 24 Nigella sativa genotypes to identify drought-tolerant and -sensitive genotypes.
Method: The experiment was a factorial arrangement based on a completely randomized design (CRD) with three replications, conducted at the Crop Physiology Laboratory of Shahrekord University. The factors comprised 24 N. sativa genotypes and five drought levels induced by PEG at osmotic potentials of 0 (distilled water, control), -0.2, -0.3, -0.4, and -0.6 MPa. Measured traits included germination percentage and rate, mean germination time, root and shoot length, seedling length, seedling fresh and dry weight, and seed vigor.
Results: Analysis of variance (ANOVA) revealed that genotype, drought, and their interaction significantly affected all germination and early seedling growth traits. The strongest positive correlations were observed between seed vigor and seedling length, seedling length and root length, and seed vigor and root length. Principal component analysis (PCA) of the nine traits identified three components with eigenvalues >1, accounting for 87.91% of the total variance. Based on the PCA biplot and Ward's hierarchical cluster analysis, the genotypes were classified into three groups: tolerant (genotypes 3, 8, 11, 24), semi-tolerant (genotypes 1, 2, 9, 12, 14, 17), and sensitive (the remaining 14). Multivariate tests (Pillai's trace, Wilks' lambda, Hotelling-Lawley trace, and Roy's largest root) confirmed highly significant differences among the three groups (p < 0.01), validating the classification robustness.
Conclusions: The findings reveal significant genetic diversity among N. sativa genotypes under drought stress. Genotypes 3, 8, 11, and 24, which showed superior germination performance, are recommended for future breeding programs. Furthermore, clustering enables the selection of parental lines with greater genetic distance (e.g., tolerant genotype 3 and sensitive genotype 5) for hybridization, facilitating the genetic analysis of drought tolerance mechanisms and supporting trait improvement efforts.
Highlights:
- Rapid, cost-effective PEG screening replaces field selection
- Root length as a reliable indicator of seed vigor
- Identifying 4 superior Nigella genotypes for drought tolerance
