Showing 2 results for Brassinosteroid
Mohammad Rezaee Chermehini, Farzad Sharifzadeh, Manijeh Sabokdast,
Volume 11, Issue 1 (4-2024)
Abstract
Extended abstract
Introduction: In order to improve seed germination under environmental stress conditions such as salinity, one of the solutions is to use seed priming. Despite this advantage of priming, the longevity of primed seeds usually decreases and it has been observed that using post-priming treatments such as heat shock can improve the longevity of primed seeds. This research investigates the effect of seed priming with salicylic acid, methyl jasmonate, and brassinosteroid under salinity stress and the effect of heat shock after priming on improving the longevity of primed seeds.
Materials and Methods: The effect of seed priming with hormonal substances such as methyl jasmonate at three concentrations of 1, 100, and 1000 micromolar and brassinosteroid at three concentrations of 25, 75, and 100 mg/liter on increasing the seed germination traits of Suaeda fruticosa was investigated under salinity stress during separate experiments. In both studied hormones, priming temperatures of 5, 10, and 15°C were used for 1 and 2 days. Hormonal seed priming with salicylic acid at a concentration of 25 mg L-1 for 2 days at 10°C -obtained from the previous results (unpublished)- was used for comparison with those of the studied treatments. To determine the most suitable accelerated aging stress for evaluating and determining the best heat shock treatment, the accelerated aging test of seeds was carried out for two, four, six, eight, and ten days. In this research, to improve the longevity of primed seeds, they were exposed to heat shock treatment at temperatures of 30, 35, and 40°C for 1, 2, 3, and 4 hours after seed priming.
Results: Both seed priming treatments with methyl jasmonate and brassinosteroid significantly increased all the tested germination traits compared to the control (without priming). This increase in traits such as germination percentage, vigor index, and seedling length in seed priming with methyl jasmonate was 46.4%, 67%, and 41%, respectively, and in the case of priming with brassinosteroid was 32%, 44%, and 38%, respectively. Also, in this research, the heat shock treatment at 40°C for four hours after priming had a significant and positive effect on seed germination. Application of the mentioned treatment increased germination by 60% at the end of the aging period compared with the control (without the application of heat shock).
Conclusions: Despite the significant increase in germination percentage by each of the hormonal substances like methyl jasmonate and brassinosteroid, the comparison of the best treatment combination of these substances with salicylic acid showed that seed priming with 25 mg L-1 of salicylic acid for two days at 10°C caused a significant increase in the percentage of germination under salinity stress. Also, the heat-shock post-priming treatment significantly improved the longevity of primed seeds.
Highlights:
- Seed priming significantly increases the seed germination characteristics of the Forssk plant against high salinity stress.
- As the aging period increases, the primed seeds experience a significant drop in germination compared with the control.
- Heat shock immediately after priming can significantly increase the longevity of primed seeds compared with the control.
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.
