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.