نشریه علوم و فناوری بذر ایران
سال یازدهم شماره 1 (پیاپی 25، بهار 1401)

Seed priming is one of the most effective methods for improving germination and seedling establishment. In order to study the effect of priming on germination of different shapes of Marigold compact petal variety (Calendula officinalis L.), a factorial experiment was conducted in a completely randomized design with three replications in 2014. The germination traits were calculated for different shapes of Marigold seedlings such as germination percentage, germination rate, seedling index, root length and shoot length. The results showed that crescent-shaped seeds exhibited the highest percentage, rate and germination index with 75.51%, 4.48 germination per day and 18.97%, respectively. In addition, the effect of osmo and hydro priming on seeds showed that the highest germination percentage (75.56%) was observed in zero bar of osmo priming and hydro priming of 8 hours. The highest germination rate in the hydro priming treatments was 8 and 16 hours, with values of 3.16 and 3.26 germination per day, respectively. The highest germination index of hydro priming treatments was recorded at 8 and 16 hours with values of 12.22 and 11.75, respectively. Priming action can be effective in reducing the negative effects of various factors during germination and afterwards. Overall, the results of this experiment showed that the use of osmo and hydro priming for the crescent-shaped seeds of Mrigold had the highest germination traits.

Nickel is an essential microelement, but the increased concentration it in the medium disrupts the germination and growth of plants. In the present study, the effect of pretreatment and exogenous proline in the seedling growth of Cucumis melo under nickel stress was investigated. For this purpose, seeds were divided into two groups. In one group, seeds were sterilized for 24h, then they soaked in 0, 10 mM proline and finally cultured in different nickel concentrations. Another group seeds were soaked in deionized water for 24 hours and then cultured in petri dishes containing the same from one another concentrations of nickel and proline. All seeds were kept for 10 days, then measured germination, and growth parameters and membrane stability. The results showed that germination parameters were not affected by nickel. Radicle was more sensitive to Ni excess than hypocotyl. The amount of malondialdehyde increased with increasing nickel concentration. Add exogenous proline significantly reduces germination percentage and germination index but it increased mean germination time. Proline pretreatment in the presence of nickel treatments improved radical length, root to shoot ratio. But the addition of exogenous proline increased hypocotyl length while radical length and their ratio decreased in lower exposure levels. However, exogenous proline reduced lipid peroxidation and membrane permeability more than similar treatments under nickel treatments. Proline, as a pretreatment as a compatible solution and antioxidant, improves the early stages of growth and reduces the damage caused by nickel toxicity in the early stages of cucumber seedling growth.

In order to investigate the effect of water deficit stress and sources of nitrogen fertilizer on germination quality and vigor of wheat seeds of Chamran cultivar, an experiment was conducted in Agricultural Research Center of Fars province. In this experiment, wheat seeds were first treated at three levels of water deficit stress (complete irrigation, water deficit stress in milky and rough stage) and four levels of nitrogen fertilizer sources (urea fertilizer 100% plant requirement, urea fertilizer 25% Along with nitroxin and nitrogen, 50% urea fertilizer with nitroxin and nitrogen, 75% urea fertilizer with nitroxin and nitrogen were produced. Then, the quality and vigor of the seeds were tested in two standard experiments of germination and accelerated aging in a factorial design with four replications. The results showed that the effect of experimental treatments on all measured traits except germination percentage was significant. Water deficit stress and sources of nitroxin and nitrogen fertilizer with 25% urea at the beginning of decline led to an increase in protein concentration (12.39%), but the lowest amount of starch (20.85 %) under the interaction of nitroxin and nitrogen fertilizer with 75% urea in 48 hours Deterioration was observed. Water deficit stress also increased the concentration of soluble sugars and decreased the grain alpha-amylase enzymes. Overall, the results of this study showed that the use of combined treatments of urea fertilizer and biofertilizers in stress conditions to feed the mother plant led to the production of seeds with higher vigor and more resistance to decay.

To investigate the effect of Wokozim Fertilizer, containing seaweed, on potato hybrids obtained from the crossing of Savalan and Satina cultivars under normal and water deficiency stress conditions was conducted in the laboratory of Zare Gostar Arta Technology Company, under in vitro conditions, during 2017. The experiment was performed as a factorial experiment in a completely randomized design with three replications. The first factor consisted of three levels of polyethylene glycol 6000 (zero, -3 and -6 bar) to apply water deficiency stress and the second factor consisted of three levels of Wokozim (zero, 30 and 60 ml /L). The effect of water deficiency stress on all traits and the effect of Wokozim on the all studied traits except for seed germination percentage was significant. The interaction effect of water deficiency × Wokozim was significant for all traits except stem length. Stem length decreased due to increasing water stress intensity. The maximum stem length (4.67 cm) was observed at the 30 ml/l of level of Wokozim fertilizer. The water deficiency stress reduced the values of all traits. According to the results, in conditions of severe stress, application of 60 ml/l of Wokozim can improve germination percentage, root and stem length, but had no significant effect on weight and number of microtubers. In addition, in conditions without stress, 60 ml /l and Wokozim can improve most of the traits.

In order to investigate the effect of priming on different aspects of germination of aged pumpkin seeds under drought stress, a factorial experiment was conducted based on a completely randomized design with four replications in the laboratory. Treatments included different levels of aging (control, 85% and 75% of control germination), salt stress (0, 75 and 150 Mmol) and priming (control, hydro, gibberellin, GR24, benzyl aminopurine and spermidine). The seeds reached the desired vigor level by accelerated ageing test. Morphological traits were also studied using seedling growth test. Mobility of seed lipid reserves, carbohydrate, number of photosynthetic pigments, photosynthesis, α-amylase and the amount of sodium ions were measured. In the study of germination traits, motility of lipid reserves, carbohydrates, chlorophyll a, photosynthesis and sodium content, salinity stress, seed deterioration and priming led to a significant change in them compared to the control seed. While in the case of shoot and root dry weight, chlorophyll b, and chlorophyll a / b ratio under salinity, seed deterioration and priming, no statistically significant change were compared to the control seed, the greatest effect of gibberellin-related seed priming was observed on germination traits and spermidine on physiological traits.

The improper harvesting time can result in producing poor quality seed because leakage from the seed coat increases under these conditions. As such, it is critical to determine the proper seed moisture at the harvesting time. This study is included two years conducted in 2018 and 2019 as a factorial in the form of a randomized complete design under three replications. The first factor contains three corn varieties (Simon, AS71 and KSC703) whereas the second factor contains four harvesting times in terms of the seed moisture content (30, 35, 40 and 45%). The obtained results indicate that the highest electrical conductivity is observed in the early harvest treatment with 45% moisture, whereas the lowest electrical conductivity is observed in the treatment with 30% moisture at the harvesting time. The early harvest with 45% moisture decreases the viability as well as the percentage and germination rate of corn seeds. The highest viability of corn seeds at 35% moisture at the harvesting time is observed in AS71 varietie. Moreover, the germination of seeds of the Simon and KSC703 varieties did not reveal a statistically significant difference in the treatment of 30% moisture at the harvesting time with 35% and 40% moisture. The treatment with 45% moisture delayed the germination rate. In general, due to the reduction in the germination response at high moisture content at maturity time for standard and aging acceleration test, 30 and 35% moisture content at maturity time were found to be appropriate to produce high quality corn seeds.

In order to identify different landraces of onion seeds in terms of germination characteristics, an experiment was conducted in a completely randomized design with four replications in the Biology Laboratory of the Faculty of Agriculture, Ferdowsi University of Mashhad in 2020. The experimental treatments were 29 native landraces of onion seeds from different regions of Iran and two improved cultivars as control. The results showed a significant difference for all measured indices amongst landraces. Also, the clustering results of the landraces, based on the apparent characteristics, showed that among the 4 clusters, the third cluster, which includes 9 landraces (Harsin, Kavar, Azarshahr, Bonab, Yasuj, Qorveh, Kashan white, Neishabour white and Qoli Qeseh) has better appearance characteristics in terms of 1000-grain weight (average 4.54 g), grain length (average 3.08 mm) and grain diameter (1.9 mm). Also, it was shown based on germination characteristics that among the six indivisual clusters, the fourth cluster with 7 landraces including Yasuj, Kashan white, Dorcheh Yellow, Turkey, Tarom, Neishabour white and Qorveh has better germination characteristics. In general, it can be concluded that based on the appearance and germination characteristics, Yasuj, Kashan white and Neishabour white landraces showed a better seed quality.

The effects of accelerated aging treatment on seed germination of Echinops was quantified using nonlinear models using Sigmoid, Segmented, Gompertz and Richards models and hydrotime model in Weibull, Normal and Gombel distribution functions. Experimental factors were seed aging for (0, 24, 48, 72 and 96 hour) at relative humidity (RH)=100%, temperature (T) =40 oC and seven osmotic potential (0, -0.2, -0.4, -0.6, -0.8, -1, -1.2 MPa). Results of experiment revealed that interaction effect of aging and osmotic stress on seed germination and germination rate of Echinopsis was significant. Seed germination parameters of Echinops were increase by aging treatment up to 72 h but it was declined at aging treatment of 96 h. Seed germination and germination rate were increased by aging treatment till 72 h but at 96 h, both were declined. Gompertz exhibited the best fit for no aged, 24 h and 48 h while sigmoid function was provided the best fit for aging at 72 and 96 h. Among all studied distribution function, it was revealed that normal distribution was the most effective one thus base potential (ψb) and hydrotime constant (θH) were -0.68 MPa and 6 MPa hour, respectively. However, after 96 h of aging treatment ψb and θH were estimated 0.731 MPa and 19.3 MPa hour, respectively. It can be concluded that freshly harvested Echinops exhibited some levels of seed dormancy which was alleviated at mild to moderate aging conditions, but after 72 h, deteriorative mechanism led to damaging effects and declined seed germination quality.

One of the methods of priming is biopriming with growth promoting bacteria to increase seed germination and stimulate seedling growth. In this study, different effects of gamma ray on bacteria as mutants, irradiated (wild type) and control bacteria and then their effect on germination and vegetative traits of seeds were investigated. Seeds were selected from the legumes, cereal and garden plants. Experiments were conducted in a completely randomized design with 3 replications. The results showed that germination in the seeds had a positive reaction to the bacteria. But bean seeds had different responses to treatments. Reaction of different seeds to mutant and wild bacteria was different. Chickpeas achieved 100% germination with growth-promoting bacteria. Soybeans, flax, mung bean, wheat and lettuce had higher germination rates than controls. In the other measured vegetative traits, the bacteria showed different responses to the bacteria compared to the control and should be carefully studied for their use. But in general it can be said that all seeds increased in most of the traits compared to control and showed a positive reaction.

To study of the effect of biological pre-treatments on germination and growth of Fenugreek (Trigonella foenum-graecum L.) seedling under natural salinity stress, a factorial experiment in a completely randomized design was conducted in three replications. Experimental treatments were biological pre-treated at four levels (control, inoculation with Azoto bio-fertilizer, inoculation with Phosphate bio-fertilizer, inoculation with both bio-fertilizers) and natural salinity (salt of Qom Lake) at five levels (zero, 3, 6, 9 and 12 dS/m).The results showed that increasing of salinity levels led to increasing of mean germination time and using of bio-fertilizer treatments and combination treatment caused this index show 22 percentages reduction at highest level of salinity compared to control treatment at same level of salinity. Salinity reduced the germination coefficient and the highest amount of this index (74.3) obtained at 3 dS/m level of salinity that compared to control treatment and at the same level of salinity showed 89 percentages increasing. Salinity reduced total chlorophyll and using of biological treatments caused amount of total chlorophyll at zero level of salinity show 155 percentages increasing compared to control treatment and at the same level of salinity. With increasing of salinity level increased soluble protein and combination treatment increased this index 12 percentages at the highest level of salinity compared to control. Under stress, plants face with oxidative stress and to confront of that use antioxidant enzymes. In this experiment, the using of biological treatments by raising of the production of antioxidant enzymes caused the reduction of salinity effects.