Showing 2 results for Stress Tolerance
Davar Molazem,
Volume 12, Issue 2 (3-2026)
Abstract
Objective: This study investigated the effectiveness of electromagnetic priming in improving drought tolerance of Hashemi rice (Oryza sativa L.) during germination and early seedling growth.
Method: A factorial experiment based on a completely randomized design with three replications was conducted in 2024 at the Islamic Azad University, Astara Branch. Rice seeds were exposed to magnetic fields (0, 50, 100, and 150 mT) for 20 or 40 minutes and then subjected to four PEG-induced drought levels (0, -2, -5, and -10 bar). Germination indecies and physiological traits including proline, MDA, and chlorophyll were measured after 25 days.
Results: The mean comparison of interaction effects showed that in the absence of an electromagnetic field (0 mT), increasing drought stress from 0 to −10 bar significantly decreased germination percentage from 97% to 66.53%, germination rate from 0.43 to 0.19 seeds day⁻¹, radicle length from 65.80 to 28.66, and plumule length from 45.33 to 17.33 mm. However, application of a 100 mT magnetic field considerably limited these reductions to approximately 24% and 49% for germination percentage and seedling length, respectively, indicating an improvement of more than 20% in maintaining germination capacity. With increasing drought stress, proline content significantly rose from 1.01 to 8.34 µmol g⁻¹ FW, and MDA increased from 4.40 to 8.00 mmol g⁻¹ FW, while chlorophyll a decreased from 0.64 to 0.17 and chlorophyll b from 0.75 to 0.32 mg g⁻¹ FW. In the control (0 mT), chlorophyll a exhibited a 72% reduction, whereas at 100 mT this reduction was limited to 56.8%, reflecting approximately 15% improvement. Regression analysis revealed that the effect of magnetic field intensity on the measured traits depended strongly on the drought stress level and did not follow a consistent pattern; under severe stress (−10 bar), no significant linear relationship was detected.
Conclusions: The application of magneto-priming within the optimal range may serve as a simple, eco-friendly, and practical approach to enhance drought tolerance in rice seeds and improve early seedling establishment under unfavorable environmental conditions. In the present study, the treatment with 100 mT for 40 minutes resulted in improved seedling vigor indices for both length and weight. These findings offer new perspectives for the application of physical technologies in agricultural stress management and provide a basis for further field-based studies.
Highlights
- Germination responses to magnetic fields are nonlinear and depend on field intensity and drought stress level.
- Electromagnetic priming at 100 mT for 40 minutes mitigates drought stress effects by up to 20% in germination traits.
- Magneto-priming offers a simple, eco-friendly strategy for improving rice seedling establishment under drought conditions.
Maryam Hashemvand, Mohammad Sedghi,
Volume 12, Issue 2 (3-2026)
Abstract
Objective: This study aimed to investigate the effects of seed priming with silicon on germination and biochemical responses of maize (Zea mays L. SC 704) under different pH levels of the growth medium.
Method: The experiment was conducted as a factorial arrangement within a completely randomized design (CRD) with three replications. Treatments consisted of four priming levels: control (distilled water) and silicon (as sodium silicate) at concentrations of 50, 100, and 150 mg L-1, and three pH levels of the growth medium (5, 6.5, and 8). The measured traits included germination indices (percentage and rate), seedling growth (fresh weight, vigor weight, and length), ion leakage (relative electrolyte leakage, REL), and biochemical indices (activities of α-amylase and protease, soluble sugar content, total protein, and silicon uptake)
Results: Deviation from the optimal pH (6.5) toward acidic (pH 5) or alkaline (pH 8) conditions significantly reduced germination and growth indices while increasing ion leakage. Seed priming with silicon, particularly at 150 mg L-1, markedly mitigated the adverse effects of pH changes. Under acidic conditions (pH 5), this treatment increased germination percentage by 63.19% compared to the non-silicon control at the same pH, reduced relative electrolyte leakage (REL), and significantly enhanced α-amylase and protease activities, soluble sugar content, total protein, and silicon uptake. The interaction between silicon and pH was significant only for germination rate, highlighting the specific role of silicon in accelerating germination under unfavorable pH conditions.
Conclusions: Seed priming with silicon at 150 mg L-1 effectively enhances germination capability and reinforces the physiological and biochemical status of maize seeds under non-optimal pH conditions, particularly acidic stress. This approach holds significant promise for improving field establishment in soils with suboptimal pH.
Highlights
- Silicon priming improved germination, rate and vigor at all pH levels, especially pH 5.
- Silicon (150 mg L-1) reduced electrolyte leakage and membrane damage under pH stress.
- Silicon enhanced α-amylase, protease, soluble sugars and total protein in seedlings.
- Silicon benefits were pH-independent, ensuring robust stress alleviation during germination.
