Iranian Journal of Seed Research

Priming and Coating Seeds with Humic Acid as an Effective Strategy in the Integrated Management of Salt-Affected Soils

Atefeh Rashidifard

Objective: Salinity is a major abiotic stress reducing crop yield and quality worldwide. This review systematically evaluates the effectiveness of seed priming and coating with humic acid (HA) as a strategy to improve germination, seedling establishment, and plant growth under salt stress.
Method: A comprehensive literature search was conducted in major scientific databases (Web of Science, Scopus, Google Scholar) using relevant keywords. Studies investigating physiological, biochemical, and molecular mechanisms of HA-mediated salt tolerance through seed priming and coating were reviewed.
Results: Seed priming and coating with humic acid significantly improved germination percentage and rate, increased root and shoot growth, and enhanced chlorophyll content and photosynthetic efficiency under salinity. HA reduced Na⁺accumulation, improved K⁺/Na⁺ ratio, and increased activity of antioxidant enzymes (SOD, CAT, POX). It also promoted ATP production and facilitated uptake of essential nutrients (K⁺, Ca²⁺, Mg²⁺).
Conclusions: Seed priming and coating with humic acid is an effective, low-cost, and environmentally friendly approach to enhance salt tolerance in crops. It accelerates seedling establishment, stimulates root growth, and reduces oxidative stress by boosting antioxidant enzyme activity. Future research should focus on synergistic effects with other biostimulants across different crops and salinity levels.

Highlights

Priming and coating seeds with humic acid boosts plant tolerance to salinity stress.
Humic acid improves soil health and nutrient efficiency sustainably.
Priming and coating seeds with humic acid is a cost-effective method for boosting crop growth and yield in salt-affected soils.

The Effect of Silicon Seed Priming on Germination and Biochemical Indices of Maize (SC 704) Across Different pH Ranges

Mohammad Sedghi

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.

Multivariate Analysis of Germination and Early Growth in Damavand Basil (Ocimum basilicum) under Sodium Carbonate Stress

Abohassan Farhang Sardrodi

Objective: This study aimed to distinguish early stimulatory effects from inhibitory responses in basil seeds under alkaline stress (sodium carbonate).
Method: An experiment based on completely randomized design was conducted with four Na₂CO₃ levels (0, 5, 15, and 30 mM) and three replications. Germination dynamics were assessed via germination percentage (GP), germination rate (GR), and mean germination time (MGT). Post-germination growth was evaluated using seed vigor index (SVI), biomass allocation (fresh/dry weights), and total biomass index (TBI). Salt tolerance indices (STI) were calculated, and multivariate analyses (correlation heatmap and PCA) were performed.
Results: A clear hormetic response was observed. At 5 mM, TBI reached its maximum (STI.TBI = 2.28), indicating significant growth stimulation. Concentrations above 15 mM caused a sharp decline in all indices. At 30 mM, germination capacity and early growth were severely reduced, along with decreased germination rate and disrupted biomass allocation. PCA explained 97.75% of total variance and clearly differentiated treatments. The heatmap showed a strong correlation (r = 0.962) between germination rate and seedling establishment.
Conclusions: A stimulatory threshold exists at 5 mM Na₂CO₃. The transition from hormesis to toxicity occurs between 5 and 15 mM, reflecting a limited adaptability range for Damavand basil. TBI and PCA-based clustering are reliable indicators for evaluating salt tolerance. These findings emphasize the need for careful soil and water management in alkaline environments.

Highlights

Mild sodium carbonate stress (5 mM) stimulated seedling growth in Damavand basil, confirming a hormetic response.
PCA effectively discriminated stress levels, explaining 97.8% of total variance.
Total Biomass Index (TBI) was identified as the most reliable indicator of alkaline stress tolerance.
Severe stress (30 mM) impaired biomass allocation and germination kinetics, leading to poor seedling establishment.

Mitigating the Adverse Impact of Salinity Stress on Germination of Wheat (Triticum aestivum cv. Sain) through Seed Priming with Chitosan Nanoparticles

Haniyeh Saadat

Objective: This study aimed to investigate the reduction of adverse effects of salinity stress on germination and related traits of wheat (Triticum aestivum cv. Sain) through seed priming with chitosan nanoparticles.
Method: The experiment was conducted as a factorial arrangement based on a completely randomized design with three replications at the University of Mohaghegh Ardabili in 2025. Treatments included four salinity levels (0, 50, 100, and 150 mM NaCl) and four levels of chitosan nanoparticles (0, 0.1, 0.2, and 0.5% weight/volume dissolved in 1% acetic acid).
Results: Germination percentage (GP) and plumule fresh weight (PFW) decreased at 150 mM salinity compared to the control (without salinity), but seed priming with 0.5% chitosan nanoparticles improved GP and PFW at the same salinity level by about 20% and 50%, respectively, compared to no chitosan application. Radicle fresh weight (RFW), radicle dry weight (RDW), plumule dry weight (PDW), seedling length vigor index (SLVI), and seedling weight vigor index (SWVI) in the 0.5% chitosan nanoparticle treatment without salinity increased by 77, 72, 83, 76, and 89%, respectively, compared to hydropriming under 150 mM salinity. With increasing salinity, proline content increased, but the application of 0.5% chitosan nanoparticles increased this trait by 32% compared to hydropriming. Protein content under no salinity and priming with 0.5% chitosan nanoparticles increased by about 76% compared to hydropriming under 150 mM salinity. Also, soluble sugar content in the treatment with 0.5% chitosan nanoparticles under 150 mM salinity increased by about 84% compared to hydropriming without salinity.
Conclusions: The results showed that the use of 0.5% chitosan nanoparticles improved germination indices and biochemical traits of wheat seeds under salinity stress.

Highlights

Seed priming with 0.5% chitosan nanoparticles improved some germination indices of wheat (cv. Sain) seeds under salinity stress.
Seed priming with 0.5% chitosan nanoparticles increased proline, protein, and soluble sugar contents in wheat (cv. Sain) seedlings.

Germination Response and SOD Activity of Two Persian Camelthorn (Alhagi camelorum) Populations to Salinity after Seed Scarification

Marjan Diyanat

Objective: Given the extent of saline lands worldwide, this study aimed to evaluate the tolerance of Persian Camelthorn (Alhagi camelorum) to salinity stress during germination and early growth stages following seed hardness removal, to promote its cultivation as a forage plant for livestock.
Method: A factorial experiment was conducted in a completely randomized design with four replications in 2023 at the Seed Analysis Laboratory of the Seed and Plant Certification and Registration Institute. Factors included: (1) seed population (Gorgan and Mashhad), (2) salinity levels (0, 100, and 200 mM NaCl), and (3) seed hardness removal treatments (immersion in 100°C water for 1 minute and concentrated sulfuric acid for 35 minutes). Germination percentage, mean daily germination time, seedling vigor index, stem length, and superoxide dismutase (SOD) activity were measured.
Results: Salinity stress significantly reduced germination percentage, as well as stem length. Germination indices differed significantly between control and 200 mM treatments. Increasing salinity decreased mean daily germination in all treatments. The highest salinity level reduced stem length by 65% and 44% in the Mashhad population, and 71% and 64% in the Gorgan population, compared to control, respectively. Treatment with 100°C water and 200 mM salinity increased SOD activity by 56.9% in the Mashhad population and 45.4% in the Gorgan population. Sulfuric acid treatment with 200 mM salinity increased SOD activity by 25.4% and 13.0% in Mashhad and Gorgan populations, respectively.
Conclusions: Sulfuric acid treatment for 35 minutes significantly increased germination percentage in both populations compared to 100°C water treatment. The greater increase in SOD activity in the Mashhad population suggests higher salinity tolerance, making it a suitable candidate for cultivation in saline lands.

Highlights

Sulfuric acid (35 min) and hot water (100°C, 1 min) effectively broke seed dormancy and improved germination.
The Mashhad population was more salt-tolerant than the Gorgan population.
Both populations countered salinity through enhanced antioxidant enzyme activity.

Electromagnetic Priming: A Novel Strategy to Enhance Drought Tolerance in Seeds and Seedlings of Rice (Oryza sativa cv. Hashemi)

Davar Molazem

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.

The Interactive Effects of Seed Scarification and Different Nitrogenous Compounds on the Germination and Seedling Growth of Astragalus adscendens

Rayhaneh Amooaghaie

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.

Evaluation of the Effect of Trichoderma harzianum on Seed Emergence and Early Growth of Quercus brantii Seedlings under Greenhouse and Natural Forest Conditions

Roghayeh Zolfaghari

Objective: The oak forests of the Zagros region, as a valuable ecosystem, have experienced extensive degradation in recent years due to various factors, including climate change and human activities. The rehabilitation of these forests requires the production of resilient, high-quality saplings. This study aimed to investigate the effect of the fungus Trichoderma harzianum as a biological growth-promoting agent on the seed emergence and early growth of Quercus brantii seedlings in order to evaluate its efficacy in improving the growth and physiological parameters of this species under both greenhouse and natural forest conditions.
Method: Seeds collected from mother trees in the Yasouj forest site were planted in pots (under greenhouse conditions) and pits (in the forest), and a biological treatment using a Trichoderma fungal solution was applied to the seeds. Subsequently, emergence, growth, and physiological traits of the seedlings were measured and compared throughout the growing season.
Results: The results showed that under greenhouse conditions, the Trichoderma treatment significantly increased the seed emergence percentage, photosystem performance index (PI), and chlorophyll index compared with the control group. However, no significant differences were observed in other growth traits, such as height, leaf number, and the dry and fresh weights of plant organs. In contrast, under natural forest conditions, the emergence percentage in the control group was significantly higher than in the Trichoderma treatment, and other growth traits showed no significant differences between the two groups. Furthermore, a significant positive correlation was observed between physiological indices (such as performance index and chlorophyll) and some growth traits (such as root length and stem dry weight) under greenhouse conditions.
Conclusions: The findings of this study indicate that the effect of Trichoderma fungus on Persian oak is complex and depends on environmental conditions (as evidenced by the significant difference between greenhouse and natural forest field conditions) and the host plant species (in comparison with previous studies on other plants). Therefore, conducting long-term field studies with different Trichoderma isolates and concentrations is recommended to achieve more practical results in Zagros restoration programs.

Highlights:

First study on the effect of Trichoderma harzianum on Persian oak (Quercus brantii), addressing a key knowledge gap in Zagros forest restoration.
Simultaneous greenhouse and field trials revealed environment-dependent effects of Trichoderma, confirming the necessity of field experiments.
Limited positive and negative effects challenge the belief that Trichoderma is always a growth promoter, emphasizing species-specific and native approaches.

Mepiquat Chloride (Pix) Improves Germination and Biochemical Stability of Sesame (Sesamum indicum cv. Darab-1) Seeds under Deterioration

Ali Moradi

Objective: Seed aging in oilseeds such as sesame is a major storage challenge, reducing germination quality and seedling vigor. The high-oil cultivar Darab‑1 is highly sensitive to storage conditions (temperature, moisture, and time). In this study, the effects of different Pix concentrations in interaction with temperature, moisture, and storage duration were investigated on germination and biochemical traits of seeds to determine the possibility of improving seed quality stability during storage.
Methods: The experiment was conducted as a four‑factor factorial arrangement in a completely randomized design with three replications. The studied factors were storage temperature (15, 25, and 35°C), seed moisture content (9, 12, and 15%), Pix concentration (0, 3000, and 4500  mg L^-1), and storage duration (30, 60, 90, 120, 150, and 180 days). After the storage period, seed physiological traits including germination percentage and rate, root and shoot length, seedling dry weight, vigor index, α‑amylase activity, and electrolyte leakage were measured.
Results: Increasing temperature, moisture, and storage duration accelerated seed aging. After 180 days, electrolyte leakage in control seeds increased from 21.47 to 72.72% when storage temperature rose from 15 to 25°C (at 9% moisture), indicating a 54% increase in membrane leakage, while Pix at 3000 mg/L reduced it by 19–80%. α-amylase activity decreased with seed deterioration, but Pix at 3000 mg/L maintained the highest enzyme activity (15.5 vs. 16.3 nmol seed^-1min^-1after 180 days). Germination percentage and rate, seedling length and dry weight, and vigor index also declined with aging; however, Pix treatment, especially at 3000 mg L^-1, significantly moderated these reductions.
Conclusions: Storage at high temperature and moisture accelerated sesame seed deterioration, reducing germination and α‑amylase activity while increasing membrane damage. Pix at 3000 mg L^-1was the most effective treatment, maintaining seed vigor and enzyme activity and reducing electrolyte leakage. Therefore, seed treatment with 3000 mg L^-1Pix before storage, especially at 15°C and 9% moisture content, can be recommended as an effective strategy to extend seed longevity and maintain quality during medium term storage.

Highlights:

Pix at 3000 mg/L effectively prevented the decline in physiological traits of sesame seeds during storage and maintained germination potential and seed vigor.
Increased temperature, moisture, and storage duration reduced α‑amylase activity and increased electrolyte leakage, indicating accelerated physiological seed aging.
Pix treatment improved seed quality under warm and humid storage conditions by reducing electrolyte leakage and enhancing membrane stability, suggesting its practical application for extending seed longevity.