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Volume 2, Issue 2 ((Autumn & Winter) 2016)
In order to evaluate the effect of seed moisture content at harvesting time and drying temperature on soybean seed germination characteristics, an experiment was conducted as factorial (2×3×2) based on Randomized Complete Block Design with three replications in Karaj and Moghan areas. The first factor was cultivar with two levels (Williams and L17), the second factor was seed moisture content with three levels (15, 20 and 25%) and the third factor was drying temperature with two levels (30 and 45 °C). Results show that the germination percentage of producing seeds in Karaj (81.3%) were higher than Moghan area (77.4%). The difference between the germination percentage of dried seeds at 30 and 45◦C with initial seed moisture content of 15% was about 5.5%, while this difference for seeds with 25% initial moisture content was about 18.5%. There was no significant difference between seedling vigor index of seeds with 15% moisture content of two cultivars that have been produced in Karaj, but at 20% moisture content, the seedling vigor index in Williams cultivar (139.7) was higher than L17 cultivar (107.3). The highest (51.42 µsm cm-1 g-1) electrical conductivity of seed leakage soluble was obtained from the L17 cultivar with 25% moisture content and 45◦C and the lowest (28.46 42 µsm cm-1 g-1) rate of it was observed in Williams cultivar with 20% moisture content and 30◦C. According to these results, we must harvest and dry soybean seeds at 30◦C when its moisture content reached under 20%.
Volume 2, Issue 2 ((Autumn & Winter) 2016)
In order to assess seed deterioration of soybean at Ardebil province, this study was conducted as a factorial experiment based on randomized complete block design in 2014. The treatments consisted of germination ability, seed moisture content and seed storing conditions. Germination ability treatment was concluded of three germination levels: 80%, 85% and 90%. Also, three rates of seed moisture content including 10%, 12% and 14%; and two seed storing conditions including seed storage of Moghan and controlled storage were considered as second and third treatments. The results indicated that seed quality significantly reduced by increasing the seed moisture content up to 14% and this moisture content was determined as inappropriate moisture for soybean seed storage. Seeds with high moisture content showed significantly lower normal seedlings percent, germination rate and seedling vigor indices. However, there was no significant difference between 12% and 10% seed moisture contents, so it can be concluded that 12% seed moisture content is proper moisture for soybean seed storage. According to the results, enhancement of seed moisture content more than 12% will result in more accelerated deterioration of soybean seed, in a way that seeds with higher moisture content, especially at inappropriate seed storage conditions will lose their quality and will cause yield reduction at field due to low plant density aroused from inadequate seedling emergence.
Volume 3, Issue 1 ((Spring and Summer) 2016)
Efficient seed germination and rapid and uniform seedling emergence are important in commercial agriculture. Therefore, the use of strategies to improve germination and seedling establishment is necessary for increasing productivity. Hydropriming has been suggested as a simple pre-germination strategy to improve seed performance. In this study, the effects of different durations of hydropriming (10, 24, 48 and 72 hours) at different temperatures (10 and 25 ˚C) compared to unprimed seeds on the vigor and germination performance of five milk thistle accessions (Ahvaz, Sari, Esfahan, Dezfol and Gachsaran) were evaluated. An experiment was conducted as a factorial experiment based on a completely randomized design with three replications. Germination performance was evaluated by final germination percentage, mean daily germination, mean germination time, the coefficient of germination, Timson's index, time to reach 50% the final germination percentage, germination value, coefficient of uniformity of germination, length and dry weight of seedlings and vigor index. The results show that germination capacity, germination rate and seedling vigor indexes increase significantly in hydro primed seeds at a temperature of 10˚C, whereas a decrease in hydro primed seeds at a temperature of 25˚C. Our results also show that the efficacy of hydropriming on seedling emergence and vigor traits depends on the priming duration and temperature. Hydropriming at 10˚C indicated the most effective on germination indicators and seedling vigor when compared to unprimed seeds. In addition, the comparison of germination and growth indicators in different durations of hydropriming in five milk thistle accessions indicated that the best duration of hydropriming for Ahvaz and Gajsaran is 72h, for Sari and Dezfol is 48 and 72h and for Esfahan is 10 and 24h. Therefore, the effect of hydropriming on germination performance and seedling vigor depends on plant association and hydropriming time and therefore, the selection of the best condition for hydropriming will improve the seed germinability and vigor.
Volume 5, Issue 1 ((Spring and Summer) 2018)
Extended abstract
Materials and Methods: The present study was carried out under greenhouse conditions, with 23±5 °C, 60% relative humidity and 70% water-holding capacity of soil. The experimental design was a completely randomized one with four replications. Soil samples were selected from Deging village, located in the city of Khash (Sistan and Baloochestan Province). In order to prepare the plant extract, the A. sieberi samples were dried in the shade and were ground to powder. Then, 190 g of the powder was put in a plastic bottle, then filled with 1 L ethanol and placed on a shaker for 24 hours. The resulting solution was filtered out and the extract was obtained. The planting was carried out in plastic pots with the capacity of 6 kg which were filled with 3 kg of soil. In each pot, 30 seeds were buried, at a depth of 3 cm. The treatments were treated at concentrations of 0.2% (2 ml in 1000 ml distilled water), 0.4%, and zero along with plant irrigation. The parameters measured included emergence percentage and rate, radicle and pedicel length, seedling dry weight, photosynthetic pigments, carotenoid contents and nutrient uptake of P. cineraria.
Results: The results showed that A. sieberi extract significantly decreased plant photosynthetic pigments. The highest chlorophyll a, b, total chlorophyll and carotenoid belonged to the control treatment and by increasing extract concentration, photosynthetic pigments decreased. In addition, the findings were that the highest and lowest nitrogen and phosphorus contents were obtained in the 0.2 and 0.4% treatments, respectively. Potassium and manganese decreased with increases in extract concentration. However, with increases in extract concentration, zinc significantly increased in the plant tissues. In general, the results showed that A. sieberi extract increases P. cineraria emergence in the 0.2% treatment.
Conclusion: In general, morphological traits and photosynthetic pigments of P. cineraria decreased with increases in the concentrations of A. sieberi extract. Artemisia extract had a different effect on the absorption of nutrients by P. cineraria. at low concentrations. It increased nitrogen and phosphorus adsorption and increased concentrations of manganese in high concentrations. The concentration of 0.2% of Artemisia extract had a positive effect on plant emergence. Given the positive effect of A. sieberi on the emergence of P. cineraria, plant extract at low concentrations can be used to increase emergence of P. cineraria, especially given that the P. cineraria has an emergence problem. However, due to the negative effect of A. sieberi on growth and absorption of nutrients in P. cineraria, the cultivation of these two plants is not recommended in dry rangelands.
Highlights:
- The extract of A. sieberi had deterrent effects on seed emergence and morphological characteristics of P. cineraria.
- Increasing the concentration of the A. sieberi extract led to a decrease in the morphological characteristics of P. cineraria.
- A. sieberi extract had negative effects on photosynthesis pigments of P. cineraria.
Volume 7, Issue 1 ((Spring and Summer) 2020)
Extended abstract
Introduction: London rocket is an important winter annual weed of the mustard family (Brassicaceae), which is propagated by seed. Germination of a seed population in response to water potential reduction is modeled using the concept of hydro time. This model has outputs that are physiologically and ecologically meaningful. One of the presumptions of the Hydro time model is the normal distribution of the base water potential among the seed population.
Materials and methods: In order to quantify the germination characteristics and determine the cardinal temperature of germination of London rocket (Sisymbrium irio L.), an experiment was done in 2018 at Science Research Branch, Islamic Azad University, Tehran, Iran. The seeds were placed at constant temperatures (5, 10, 15, 20, 25, 30, 35, 40 and 45 °C). Germination percentage, germination rate, root length, shoot length, seedling length and seedling fresh weight were evaluated. Intersected-lines, dent-like and quadratic polynomial models were used to determine cardinal temperatures. London rocket seed germination was tested across a range of water potential (0, -0.2, -0.4, -0.6 and -0.8 MPa) at the optimal temperature of 22.80 °C. The hydro time model, based on the normal distributions was fitted to data.
Results: Results showed that seed of London rocket did not germinate at temperatures of 5, 35, 40 and 45° C, and 25° C was the best temperature for seed germination (48%). The longest root length (4.49 mm) was observed at 20°C, which did not have significant differences with temperatures of 15 and 25 °C. The longest shoot length (10.19 mm) was obtained at 25 °C and there were not any significant differences among this temperature and temperatures of 15 and 20 °C. Similar trend with the trait of root length was observed for the trait of seedling length. The best model for estimating the cardinal temperatures in London rocket was intersected-line model with respect to coefficient of determination and mean square error. According to the intersected-lines model in London rocket, the minimum, optimum and maximum temperatures were calculated 5.83, 22.80 and 37.91°C. According to the hydro-time model based on normal distribution, the hydro-time constant and the base-water potential (which is a threshold for germination beginning) of London rocket degree were 284.28 (MPa/h) and -1.18 (MPa) at 22.80 °C, respectively.
Conclusions: Knowledge of germination and emergence of weeds also helps to predict the potential distribution to new habitats. The obtained coefficient of determination (0.94) between observed germination and predicted germination showed that the hydro time model based on normal distribution fitted well to germination percentage of London rocket seed. Due to the low hydrotime coefficient of this weed and the drought problem that most provinces face, it is expected that this weed will become more problematic in most provinces of Iran in the future.
Highlights:
1- The best temperature for germination of London rocket seed is 25 °C.
2- The best model for estimating the cardinal temperatures in London rocket is intersected-line model
3- The hydro-time constant and the base-water potential of London rocket degree based on normal distribution are 284.28 (MPa/h) and -1.18 (MPa) at 22.80 °C, respectively.
Volume 9, Issue 2 ((Autumn & Winter) 2023)
Introduction: One of the major reasons behind the unstable yield of chickpea, is the simultaneity of the reproductive stage with drought and late-season heat. Autumn sowing of chickpea is among the suitable approaches to improve chickpea yield. On the other hand, freezing stress is a limiting factor in the autumn sowing of chickpea. Recently, seed priming has been developed as an essential method to induce plant tolerance to environmental stress. The priming will result in a rapid response of the plant to stress. Freezing, as an environmental stress, limits the growth and development of many plants in different parts of the world. Studies show that in addition to acclimation, short-term biotic and abiotic stresses as pretreatment could also increase the plant's tolerance to cold stress. This process alters the freezing response positively.
Material and Methods: This experiment was conducted as a factorial in a completely randomized design with three replicates at the greenhouse of the Research Center for Plant Sciences of Ferdowsi University, Mashhad Iran, in 2018. The experimental factors consisted of various temperatures (0, -12, -15, and -17 °C), seed priming at 10 levels (control (without priming), hydropriming, priming with sodium chloride, salicylic acid, sodium nitroprusside, phosphate solubilizing bacteria and potassium solubilizing bacteria, amino acids, potassium nitrate, and zinc sulfate) and different chickpea genotypes (MCC505, ILC8617, MCC495, and Saral cultivar). In this experiment, the measured parameters included survival percentage, electrolyte leakage percentage, and lethal temperature resulting in 50% mortality according to the electrolyte leakage and survival percentage.
Results: The results showed that the application of hydropriming, priming with sodium nitroprusside and zinc sulfate had favorable effects on the survival rate and electrolyte leakage. Among these, priming with sodium nitroprusside increased the survival percentage compared to the control (23%) at the -15 and -17 °C in the Saral cultivar, at -15 °C in the ILC8617 genotype, and at -12 and -15 °C in the MCC495 genotype treatment to 68, 58, 85 and 55 percent, respectively. In addition, this treatment reduced the electrolyte leakage by 13% at -15 °C in the ILC8617 genotype compared to the control treatment. Further, the mentioned treatment resulted in a 40% reduction in lethal temperature resulting in 50% mortality according to the survival percentage. In the MCC495 genotype compared to the control treatment.
Conclusion: Overall, the cold stress in the chickpea plants resulted in an increase in electrolyte leakage and a decrease in the survival percentage. Application of sodium nitroprusside priming by improving cold stress tolerance resulted in a reduction of lethal temperature resulting in 50% mortality based on electrolyte leakage and survival percentage results. Additionally, the applied priming in improving the cold stress tolerance mainly improved the survival percentage compared to the improvement in the electrolyte leakage.
Highlights:
- The effect of different primings on the freezing tolerance of chickpeas was investigated and determined.
- The freezing tolerance threshold of chickpea seedlings was determined at the laboratory under different primings.
- The respondents of genotypes to priming and the behavior of genotypes towards each other were investigated.
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Seed Science and Technology, Seed Physiology, Seed Ecology, Modeling, Seed Health, Germination Characteristics, Seed Dormancy, Seed Ageing, Seed Storage, Seed PrimingVote
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