Iranian Journal of Seed Research

Effect of seed priming with vitamin U on seed germination and physiological and biochemical characteristics of sunflower (Helianthus annuus) seedlings under salinity stress

Haniyeh Saadat

Extended abstract
Introduction: Environmental stresses, including salinity, result in the overproduction of reactive oxygen species, which, at high levels, can cause oxidative damage, impair membrane lipid functions, inactivate enzymes, and impede the metabolic activities of the plant. Salinity affects seedling growth through osmotic stress, ionic toxicity, lack of absorption of essential elements and water, production of free radicals, cell membrane destruction, and reduction of cell division. Seed priming is a quick, easy, low-cost, and effective strategy for improving germination. It is a seed treatment before planting in which seeds are fully immersed in special solutions and dried until further use. Seed priming assists the germinating seed in mitigating saline stress by neutralizing ionic toxicity or by promoting defense mechanisms. This study aimed to assess the effect of seed priming with vitamin U (S-Methylmethionine) on germination and the physiological and biochemical characteristics of sunflower seedlings under salinity stress.
Materials and Methods: This experiment was conducted in 2023 as a factorial based on a completely randomized design with three replications at the University of Mohaghegh Ardabili. Experimental treatments included four salinity levels (0, 50, 100, and 150 mM) and three levels of vitamin U (0, 2, and 4 mM).
Results: The results showed that salinity reduced the germination and growth indicators, including Germination Rate (GR), Germination Percentage (GP), Mean Daily Germination (MDG), Seedling Length (SL), Seedling Dry Weight (SDW), Seedling Length Vigor Index (SLVI), and Seedling Weight Vigor Index (SWVI); but seed pretreatment with different levels of vitamin U, especially the level of 4 mM, improved these traits. Daily Germination Speed (DGS) was higher by about 25% compared with the control treatment without salinity and, in priming with vitamin U compared with the control (distilled water), it showed a decrease of about 32%. Compared with the control (distilled water), the catalase, peroxidase, superoxide dismutase activities, and proline content of seedlings obtained from primed seeds increased respectively by 9%, 8%, 32%, and 47% after vitamin U treatment. With increasing salinity levels, there was a reduction trend in total seed protein content (0.384 mg g^-1 FW), and the lowest total seed protein content was observed at salinity 150 mM. Mean Germination Time (MGT) and malondialdehyde content of seedlings in the priming with a concentration of 4 mM vitamin U and without salinity showed a decrease of about 73% and 21%, respectively, compared with the control (distilled water) and salinity 150 mM.
Conclusions: The results of this research showed that sunflower seed priming with vitamin U at a concentration of 4 mM is the most effective method to improve the germination and biochemical characteristics of seedlings, and stimulating antioxidant enzymes can reduce the harmful effects of salinity on some traits in sunflower seedlings and improve seedling growth.

Highlights:

Seed priming using vitamin U improved germination indices of sunflower seed under salinity.
Priming with vitamin U decreased the content of malondialdehyde and increased the amount of proline and protein.
The concentration of 4 mM vitamin U revealed a better effect on germination indices and biochemical characteristics.

Assessment of germination indices and early growth of Camelina (Camelina sativa) seedlings in response to osmotic and salinity stresses

Mohadeseh Shamsaddin Saied

Extended abstract
Introduction: Growth, development, and ultimately production of plants are affected by several environmental factors. Drought and salinity are major environmental stresses that have irreparable effects on all stages of germination, plant growth, and the structure and activity of organs. The germination stage and seedling establishment are more sensitive to osmotic and salinity stresses, so it is important to evaluate the germination indices under stress conditions for plant cultivation in dry and saline environments.
Materials and Methods: To investigate the effect of different levels of osmotic and salinity on germination and early growth of camelina (Camelina sativa L.), two experiments were conducted separately in a completely randomized design in the laboratory of Bardsir Faculty of Agriculture, Shahid Bahonar University of Kerman in 2023. In the first experiment, polyethylene glycol solution (PEG 6000) at -0.2, -0.4, and -0.6 MPa levels was applied to generate the osmotic potential. In the second experiment, NaCl at 50, 100, and 150 mM concentrations was used. In both experiments, distilled water was used to create zero stress (control).
Results: The results showed that mild osmotic (-0.2 MPa) and salinity (50 mM) stresses had no significant adverse effect on seedling establishment. However, increased intensity of osmotic and salinity stresses significantly reduced germination percentage and rate, seedling vigor length index, seedling dry weight, radicle length and dry weight, and plumule length and dry weight, so that drought stress at -0.6 MPa reduced the length and dry weight of the root and the length and dry weight of the plumule by approximately 40.40%, 57.4%, 49.2%, and 53.3% compared with the control, respectively. The highest level of salinity stress (150 mM) caused a decrease of 37.8%, 56.8%, 45.3%, and 55.4% in the length and dry weight of the root and the length and dry weight of the plumule compared with the control, respectively. An increment of MDA content, soluble carbohydrates, and the amount of free amino acids was observed at moderate (-0.4 MPa) and severe (-0.6 MPa) osmotic stress and 100 and 150 mM salinity stress levels.
Conclusions: Since camelina is a new plant in Iran, evaluating the response of this plant to different levels of osmotic and salinity stress during germination and early growth stages of the seedling provides the possibility of its cultivation and development in the dry lands of different regions of the country. It seems that mild drought (-0.2 MPa) and salinity (50 mM) stresses did not have a significant adverse effect on camelina germination indicators, but if the stress level exceeds the plant's tolerance range, it leads to decreased germination traits. Recommending the cultivation of this species requires studying its stability, compatibility, and agroecological characteristics.

Highlights:

Germination characteristics and initial growth of camelina seedlings were investigated under drought and salinity stress conditions.
The tolerance threshold of camelina seedlings was evaluated to different water potentials and salinity stress.
The sensitivity of germination components to salinity stress was higher than that of osmotic stress.

Enhancement of the seed germination characteristics and longevity of Forssk (Suaeda fruticosa) under salinity stress using hormone-priming and post-priming heat-shock treatments

Farzad Sharifzadeh

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.

Response of germination and growth indices of seedlings of five weed species as affected by leaf extract allelopathy of Thuja orientalis

Hamzeh Amiri

Extended abstract
Introduction: Allelopathy is the same as chemical warfare among plants. Today, global human efforts in agriculture are allocated towards reducing chemical pesticides and introducing new biological methods to control weeds. One of the proposed solutions for weed management is isolating allelochemical compounds from plants and using them as natural herbicides.
Materials and Methods: The present study was conducted to investigate some germination and biochemical properties of the weeds Taraxacum officinale, Achillea millefolium, Rumex acetosa, Althaea officinalis, and Amaranthus retroflexus As affectedby aqueous extract concentrations from the leaves of Thuja orientalis. The experiment was carried out in a completely randomized design with three replications. Aqueous leaf extracts of Thuja orientalis were used at concentrations of 0, 5%, 10%, 20% and 30%.
Results: The results showed that the aqueous leaf extract of Thuja orientalis had a significant effect on all the studied traits, and the highest inhibitory effect was observed at a concentration of 30% of the extract. In Taraxacum officinale, Achillea millefolium, Rumex acetosa, Althaea officinalis, and Amaranthus retroflexus, the germination percentage (93.33%, 88.55%, 48.3.%, 27.36%, and 40.5%), germination rate (100%, 76.36%, 39.28%, 71.72%, and 57.47%), germination coefficient (100%, 77.5%, 39.56%, 70.9%, and 51.47 %), germination index (57.2%, 72.6%, 84.61%, 72.5%, and 85.6%), peak value (67.9%, 48.7%, 61.4%, 70.9%, and 57%), germination value (43.2%, 39%, 46.9%, 53%, and 59.8%), daily germination speed (100%, 77.5%, 39.56%, 70.9% and 56.02%), seed vigor index (69.9%, 92.7%, 97.5%, 93.2%, and 92.1%), and relative water content (53.1%, 38.35%, 35.37%, 37.65%, and 47.1%) decreased compared with the control, while the mean germination time (51.6%, 71.6%, 50.7%, 60.3%, and 60.5%) and ion leakage (24.23%, 15%, 18.33%, 17.3% and 20.23%) increased compared with the control. The results of this study showed that the seeds of Taraxacum officinale were more sensitive to the inhibitory effects of the aqueous leaf extract of Thuja orientalis compared with the seeds of other studied weeds.
Conclusions: Considering the presence of monoterpene compounds such as alpha-pinene, sabinene, beta-phellandrene, and delta-carene, as well as phenolic compounds in Thuja orientalis, it seems that the allelopathic effects of this plant are mainly due to the presence of these secondary metabolites. The significant allelopathic effects of the aqueous leaf extract of Thuja orientalis at high concentrations can make it a potentially effective and environmentally friendly tool in controlling the studied weed species (Taraxacum officinale, Achillea millefolium, Rumex acetosa, Althaea officinalis, Amaranthus retroflexus) in this research.

Highlights:

Leaf extract of Thuja orientalis has significant allelopathic effects on seed germination of the studied plants.
Among the studied seeds, the seeds of the Taraxacum officinale plant are more sensitive to the aqueous extract of Thuja orientalis compared with others.
The aqueous extract of Thuja orientalis leaves led to undesirable effects on the growth and seed germination of the studied plants by damaging cellular membranes.

Investigation of germination, reservoirs content, and enzyme activity in Lallemantia iberica and Lallemantia royleana seeds under natural and artificial aging conditions

Arezoo Paravar

Extended abstract
Introduction: Production of high-quality seeds is a major concern in the agriculture industry. The lifespan of a seed, which can extend over several decades, is essential for safeguarding the plant's genetic resources. Storage conditions, including seed moisture level, relative humidity, gases (such as oxygen, nitrogen, and carbon dioxide), and temperature, are the primary factors that determine seed lifespan. Among these aging treatment, oxygen has the most detrimental effect on seed germination, storage metabolic activities, and enzyme activity of dried seeds. Lalemantia iberica and Lallemantia royleana seeds contain high levels of fatty acids, especially linolenic acid (56-67%), which have significant beneficial effects on health. However, a large number of L. iberica and L. royleana seeds deteriorate due to inadequate storage conditions by most farmers. The aim of this study is to investigate the effects of different storage conditions, especially natural and controlled aging, aging with oxygen, and nitrogen on germination, chemical activities, metabolic reserves, and enzymatic activities of dry L. iberica and L. royleana seeds.
Materials and Methods: A factorial experiment based on a completely randomized design with four replications was carried out in the seed science laboratory at the Faculty of Agriculture, Shahid University in 2021. The experimental treatments included storage environments (control, natural aging, controlled aging, and aging with oxygen and nitrogen pressure) and plant species (Lallemantia iberica and Lallemantia royleana).
Results: The results indicated that aging with oxygen had the most detrimental impact on the germination rate, seed germination, reservoirs content, and the activity of alpha and beta amylase enzymes, compared with controlled and natural aging in both species. Conversely, the highest levels of electrical conductivity, hydrogen peroxide, lipid peroxidation, and saturated and unsaturated fatty acids were observed in dry seeds stored under oxygen aging conditions. In comparison to artificial aging (controlled aging and oxygen aging), seeds stored under natural aging conditions exhibited the highest germination rate, storage compound content, and α amylase enzyme activity. Throughout the storage process, it was observed that the deterioration rate was higher in the dry seeds of L. iberica compared with L. royleana.
Conclusions: Aging with oxygen can be regarded as a rapid artificial aging method for assessing the longevity of dry seeds. Conversely, the use of low temperature and humidity conditions in natural aging can be considered a practical method for preserving the quality and longevity of seeds. Due to their high content of storage compounds (sucrose, starch, and total sugar content), L. royleana seeds can be stored for extended periods.

Highlights:

Seed aging led to an increase in biochemical indices such as lipid peroxidation, hydrogen peroxide, and saturated and unsaturated fatty acids.
The rate of deterioration in dry seeds of L. iberica was higher than those of L. royleana.
The content of storage compounds and the activity of amylase enzymes were higher in L. royleana seeds compared with L. iberica.

Evaluation of the allelopathic potential of barley (Hordeum spontaneum) on the germination morphophysiological, and biochemical characteristics of cress (Lepidium sativum)

Ebrahim Gholamalipour Alamdari

Extended abstract
Introduction: Chemical compounds in plants include primary or secondary compounds. The allelopathic compounds are mainly of the secondary type, which are released by ways such as leaching, decomposition of plant residues, volatilization, and root exudation. Plants with allelopathic properties have a negative or even positive effect on the germination and growth of other plants by releasing substances in their surroundings. These effects depend on the type of organ, concentration, plant growth location, physiological maturity, etc.
Materials and Methods: An experiment was conducted to evaluate the allelopathic potential of wild barley (Hordeum spontaneum) weed on some germination, morphophysiological, and biochemical characteristics of a reference plant sensitive to allelochemicals, cress (Lepidium sativum), in 2021. This experiment was conducted in the form of a completely randomized design with three replications. The treatments included different concentrations of H. spontaneum aqueous extract at 11 levels (0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100%).
Results: The results showed that different concentrations of H. spontaneum aqueous extract had a significant decreasing effect on the percentage and rate of seed germination, radicle and shoot length, seedling length vigor index, radicle and shoot dry weight, as well as photosynthetic pigments (i.e., chlorophyll a, b, total, and carotenoids) of cress. Their effectiveness was dependent on the concentration threshold of the aqueous extract. In contrast, the content of proline amino acid , soluble sugars, ion leakage, catalase activity, guaiacol peroxidase enzymes, the concentration of malondialdehyde, and phenolic compounds showed an increasing trend compared with the control. In most cases, the highest increase in these compounds was obtained at the 100% aqueous extract concentration of H. spontaneum. This indicates the oxidative stress and high cytotoxicity caused by harmful compounds present in the aqueous extract of H. spontaneum.
Conclusions: According to the results of this experiment, it can be decucted that the aqueous extract of H. spontaneum, due to its allelopathic properties, prevented germination and seedling growth of L. sativum. Therefore, according to the proof of the harmful effect of H. spontaneum and its high biomass, it may be possible to introduce the bioactive compounds present in this plant for the production of environmentally friendly herbicides or even the potential to produce new formulations of synthetic herbicides in case its positive effect on other species is proven.

Highlights:

The difference in the effect of different concentrations of Hordeum spontaneum weed aqueous extract on germination and seedling growth of a reference plant sensitive to the allelochemicals, Lepidium sativum, is related to their concentration threshold.
The significant decrease in germination characteristics and photosynthetic pigments of L. sativum indicates the intensity of oxidative stress caused by the harmful compounds in the aqueous extract of H. spontaneum.
The allelopathic characteristics of H. spontaneum weed can be a suitable candidate for the production of biological herbicides.

Salinity stress tolerance in Iranian spring wheat cultivars during germination

Hadi Alipour

Extended abstract
Introduction: The germination stage in plants, including wheat, is an extremely susceptible stage to biotic and abiotic stresses. Plant establishment the in the early stages of growth, especially in the germination stage, is always notably important. Salinity stress is one of the abiotic stresses that cause much damage annually, especially in arid and semi-arid regions. Therefore, identification and use of cultivars tolerant to salinity stress is one of the effective ways to reduce the negative effects of salinity stress.
Materials and Methods: In the present study, response of 64 spring wheat cultivars during the germination stage at two levels of salinity stress (zero as a control and 12 dS/m of sodium chloride) was investigated in the form of a simple lattice design with two replications at the Genetics Laboratory of the Faculty of Agriculture, Urmia University. During seven days, germination percentage, germination index, germination rate, germination energy, seedling vigor, mean germination time, and mean germination rate, and after the seventh day, seedling length, shoot length, root length, ratio of shoot length to root length, seedling fresh weight, and seedling dry weight were measured.
Results: Among the studied cultivars, a statistically significant difference was observed at the probability level of 1% in terms of all traits including radicle length, shoot length, seedling length, fresh weight, dry weight, radicle to shoot length ratio, germination index, germination rate, germination energy, germination percentage, seedling vigor, mean germination time, and mean germination rate. Based on the results of factor analysis, under both normal conditions and salinity stress, the studied traits were grouped into four main factors, and these four factors explained 92.74% of the changes under normal and 93.85% under salinity stress conditions. Using cluster analysis, cultivars were grouped into three and two clusters under normal and salinity stress conditions, respectively.
Conclusions: Based on the results of bi-plot obtained from factor and cluster analyses, the cultivars Moghan 2, Bistun, Akbari, Moghan 3, Dastjardi, Marvdasht, Gahar, and Mahdavi are the preferred cultivars and the cultivars Darya, Bam, Tajan, Sistan, Frontana, Kavir, and Afogh were introduced as undesirable cultivars in terms of the traits measured in this experiment, which can be used in breeding projects.

Keywords: Bread wheat, Germination, Multivariate analysis, Salinity stress
Highlights:

A great diversity was observed among Iranian spring wheat cultivars in terms of salt tolerance during germination.
Mahdavi, Dastjardi, Bistun, Akbari, Moghan 2, Moghan 3, Gahar, and Marvdasht were identified as salt-tolerant cultivars during germination.

Comparative analysis of seed germination in Thymus daenensis and T. vulgaris under water potential stress using hydrotime model

Atefeh Sabouri

Extended abstract
Introduction: Seed germination and seedling establishment are the most sensitive stages in the life cycle of a plant. Among the environmental factors, water potential is an important factor affecting the seed germination of various plants. This research aims to evaluate the effects of water potential on germination indices and quantify the effect of water potential the germination responses of Thymus medicinal plant seeds.
Materials and Methods: A factorial experiment was carried out in the form of a completely randomized design with four replications at the laboratories of the Department of Agronomy and Plant Breeding, Ilam University in the winter of 2023. The factors of the experiment included two types of Thymus (Thymus daenensis and T. vulgaris) and water potential stress induced by polyethylene glycol (PEG-6000) at six levels (0, -0.1, -0.3, -0.5, -0.7, and -0.9 MPa).
Results: The results showed as the water potential decreased to -0.1, -0.3, -0.5, and -0.7 MPa, seed germination percentage respectively went down by 8.43, 43.26, 61.80, and 88.76% in T. daenensis and 19.74, 44.08, 61.18 and 92.76% in T. vulgaris compared with water potential stress-free conditions. Also, T. vulgaris did not germinate at a water potential of -0.9 MPa, whereas some seeds of the T. daenensis plant germinated under this condition. The highest germination rate in both T. daenensis and T. vulgaris species was observed under stress-free conditions, and there was significant difference between the species. Four statistical distributions including normal, logistic, log-logistic, and Gumbel, were compared to quantify the germination response of Thymus to water potential. In order to evaluate the models, corrected Akaike information criterion (AICc), the coefficient of determination (R²_adj), and root mean square error (RMSE) were used. The lowest AICc index values for T. daenensis were associated with the log-logistic and logistic distributions (-2012 and -2006), and the Gumbel distribution (-1665) in T. vulgaris, suggesting the superior distributions for quantifying Thymus's response to water potential. Estimation of parameters related to the hydrotime model showed that T. daenensis species had a lower hydrotime constant value (θ_H)(23.91 MPa hour^-1) compared with T. vulgaris (28.06 MPa hour^-1), which indicated a higher germination rate in T. daenensis. The value of ψ_b(50) in T. daenensis (-0.455 MPa) was lower than that of T. vulgaris (-0.388 MPa). Therefore, based on the results, T. daenensis showed a greater ability to tolerate drought during the germination stage.
Conclusions: In general, the results showed that the effects of water potential stress on the germination components of T. vulgaris were greater than those of T. daenensis, and according to the parameters of the hydrotime model, T. daenensis was more tolerant than T. vulgaris.

Highlights:

The best distribution in the hydrotime model was determined for predicting Thymus daenensis and Thymus vulgaris seed germination under water potential stress conditions.
The threshold level of water potential stress causing a significant decrease in the germination components of Thymus daenensis and Thymus vulgaris was determined.
Based on the hydrotime model, Thymus species was determined to be more tolerant to water potential stress during germination.

Quantifying seed germination response of Kochia (Kochia scoparia) to varying temperatures and osmotic stress due to salinity

Farzad Sharifzadeh

Extended abstract
Introduction: Currently, temperature and salinity stresses are spreading globally, which have a detrimental impact on the performance of various plants, particularly during seed germination and seedling growth stages. Therefore, the objective of this laboratory study was to examine the influence of temperature treatments and salinity levels on germination characteristics and initial seedling growth of kochia.
Materials and Methods: In the first experiment, temperature at nine levels (1, 5, 10, 15, 20, 25, 30, 35, and 40°C), and in the second experiment, salinity (osmotic potential at six levels (no stress, -0.4, -0.8, -1.2, -1.6, and -1.8 MPa) were considered as experimental treatments. In order to determine the cardinal temperatures (base, optimal, and ceiling) of germination in kochia seeds, non-linear regression models including the segmented, dent-like, and modified beta models were used.
Results: In the first experiment, the response of kochia germination rate was predicted by a segmented function with R², RMSE, and AIC (Akaike) values of 0.92, 1.32, and 65.69, respectively, which indicates the high accuracy and precision of this model in predicting the cardinal temperatures of kochia seed germination compared with the other two models. In this model, the estimated base temperature for germination was 0.7°C, the optimal temperature was 20°C, and the ceiling temperature was 44.3°C. In the second experiment, salinity stress negatively affected the characteristics of seed germination in kochia, including germination percentage, germination rate, percentage of normal seedlings, seedling length, and seedling vigor index. The highest germination percentage of kochia seeds was observed under salt-free conditions with 88.66%, which decreased to 13% under -1.8 MPa salinity conditions.
Conclusions: In general, the results showed that the segmented model is more efficient and accurate than the other two models in predicting germination of kochia seeds under different temperature treatments. Also, increasing levels of salinity stress significantly reduced germination potential and seedling growth of kochia seeds, so that at a stress level of -1.8 MPa, germination rate decreased by 75% compared with stress-free condition.

Highlights:

The cardinal temperatures (base, optimum, and ceiling temperatures) of kochia seed germination were determined.
This research introduced 1°C temperature and -1.8 MPa of salinity level as low temperature stress and critical salinity, respectively.

Effect of sodium nitroprusside priming on seed germination indices and seedling biochemical traits in rice (Oryza sativa) under salinity stress

Haniyeh Saadat

Extended abstract
Introduction: Salinity is the most significant environmental stress that limits plant productivity by affecting morphology, physiology, and biochemistry of plants, especially in semi-arid and arid regions. Salinity disrupts and eventually delays seedling growth by delaying seed germination and reducing the germination rate. Seed priming stands out as a quick, easy, low-cost, and effective strategy for improving germination, seedling growth parameters, and overall plant defense against abiotic stresses in many crops. It is defined as the pre-sowing seed treatment during which seeds are immersed in water or chemical solutions and are dry until further use. The aim of this study was to assess the effect of priming with sodium nitroprusside on germination indices and biochemical traits in rice seedlings under salinity stress.
Materials and Methods: This experiment was conducted as a factorial based on a completely randomized design with three replications at the University of Mohaghegh Ardabili in 2023. Experimental treatments included four salinity levels (0, 50, 100, and 150 mM) and three levels of sodium nitroprusside (0, 40, and 80 µM).
Results: The results showed that salinity reduced germination and growth indicators including mean daily germination (MDG), germination coefficient (GC), allometric coefficient (AC), radicle length (RL), pedicel length (PL) and seedling length (SL), as well as radicle and pedicel fresh and dry weight (RFW, PFW, RDW and PDW), but seed pretreatment with different levels of sodium nitroprusside, especially the level of 80 µM, improved these traits. Salinity reduced the seedling moisture percentage (SMP), so that the highest SMP (70.13%) was observed in the control treatment. The highest daily germination rate (DGR) and malondialdehyde content (MDA) were observed at a salinity of 150 mM. Priming decreased DGS and MDA, so that the lowest DGS (0.08) and MDA (0.159 mM g^-1 FW) were obtained in priming with 80 μM sodium nitroprusside. Also, salinity decreased the activity of the α-amylase enzyme, so the lowest α-amylase activity (7.93 mg g^-1 FW seed) was obtained in the control (distilled water) and at a salinity of 150 mM.
Conclusions: The results showed that seed treatment with sodium nitroprusside at 80 µM is the most effective method to improve rice germination and biochemical traits under salinity stress. It can reduce the harmful effects of salinity on some traits in rice seedlings and improve seedling growth.

Highlights:

Seed priming using sodium nitroprusside improved the germination indices of rice seeds under salinity.
Priming with sodium nitroprusside decreased MDA content and increased α-amylase activity.
The concentration of 80 µM sodium nitroprusside showed a better effect on germination indices and biochemical characteristics.

Enhancing the germination of deteriorated triticale (x Triticosecale) seeds with hormone priming

Mohammad Sedghi

Extended abstract
Introduction: Germination and seedling growth are one of the most important stages of plant growth, which determine the degree of success of agricultural systems in production. Seed deterioration due to storage conditions is a challenge that results in diminished germinability poor seedling establishment, the loss of seed vigor, and finally seed mortality. Thus, it is necessary to use methods to increase seed germinability and enhance seedling establishment. The use of plant hormones is one of the methods that can increase seed germinability and optimal plant growth under seed deterioration conditions. Seed priming with plant hormones is among simple and cheap methods to improve seed germination, accelerate seedling growth and establishment, germination uniformity, and production of vigorous seedlings. The purpose of this experiment is to determine the most effective pretreatments of growth hormones to improve the germination and seedling establishment characteristics of deteriorated triticale seeds.
Materials and Methods: To examine the effect of priming on germination indices and some biochemical traits of deteriorated triticale seeds, a factorial experiment was performed in a completely randomized design with three replications at the Laboratory of Seed Science and Technology, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili in 2023. Treatments included seed deterioration (5%, 15%, and 25%) and priming (no prime, distilled water, cytokinin, spermidine, salicylic acid, and auxin).
Results: The results showed that seed deterioration reduced the germination percentage. Priming reduced the effect of seed deterioration and improved the germination percentage by 36.9%. As seed deterioration increased, radicle length, seedling length, vigor index, protein content, and protease activity decreased, whereas priming mitigated the effect of seed deterioration on these traits. At the lowest level of seed deterioration (25%), priming with auxin increased radicle length, plumule length, protease activity, and seedling length vigor index by 72.07, 62.06, 73.27, and 77.06, respectively, compared with no priming.
Conclusions: In general, it seems that triticale seed priming with auxin can invigorate deteriorated seeds and increase germination and seedling production uniformity.

Highlights:

Auxin pretreatment had the greatest effect on improving the quality and germination characteristics of deteriorated triticale seeds.
Effects of using growth regulators pretreatment were investigated in deteriorated triticale seeds.

Evaluation of drought stress effect on germination characteristics of some advanced dryland bread wheat lines

Hamidreza Nooryazdan

Extended abstract
Introduction: Drought stress in dryland wheat cultivation, where the plant solely relies on rainwater, can have a detrimental effect on plant growth. Given the lengthy duration of breeding projects, identifying stress-tolerant breeding lines at the germination stage can significantly reduce the time and cost of dryland wheat breeding programs for developing drought-resistant varieties. Identifying the stress tolerance of unreleased lines through laboratory simulation of drought stress is among novel methods to aid in selecting drought-tolerant varieties in the final stages. Moreover, the germination stage is crucial for plant establishment. This stage is critical for plant growth and development and can significantly impact bread wheat yield in case tolerant lines are available.
Materials and Methods: This experiment was conducted to investigate the germination characteristics of 11 advanced dryland bread wheat lines at four osmotic potential levels (-2, -4, -6, and -8 bars) induced by polyethylene glycol 6000 along with a control (for a total of five levels), under laboratory (controlled) conditions at Persian Gulf University. The investigation was performed as a factorial experiment in a completely randomized design (CRD) with three replications. Traits in this experiment including germination percentage, germination rate, growth rates of radicles and plumules, dry weight and length of radicle and plumule, seed vigor indices I and II, seedling length, and allometric coefficient were measured.
Results: The mean of all traits decreased with increasing stress levels. Results of ANOVA showed a significant interaction at the 1% level between the lines and drought stress treatments. Therefore, physical slicing analysis was conducted at each stress level to compare the lines. The response of the lines to different traits was of an ordinal interaction type. As drought stress levels increased, germination percentage and rate, radicle and plumule growth rates, and seedling length decreased. Overall, lines 3 and 4 exhibited the highest germination percentage (58.86) and rate (3.60 seeds per day), as well as radicle (0.85 cm per day) and plumule rates (0.70 cm per day), and radicle (8.83 cm) and seedling (7.12 cm) length.
Conclusions: The response of the lines to different osmotic stress levels varied in terms of various traits. Based on the traits evaluated, lines 3 and 4 exhibited superior drought stress tolerance. These lines can be utilized in future breeding programs.

Highlights:

Evaluating and screening wheat breeding lines for drought tolerance was performed by simulating stress conditions in the laboratory and comparing morphological traits in early plant growth stages.
The response of the lines to similar levels of drought stress was heterogeneous, and physical slicing analysis based on each stress level revealed an ordinal interaction between stress and line levels.