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Showing 5 results for Antioxidant Enzymes

Farzaneh Fakhari, Hossein Sadeghi,
Volume 3, Issue 1 (8-2016)
Abstract

There have been a few studies on removing the seed pods in annual medics, despite its importance. To investigate the role of pod removal on seed germination, seedling growth and antioxidant enzyme activities in annual medic (Medicago scutellata L.) Under salt stress, a factorial experiment was conducted based on a completely randomized design with four replications in 2014. Salinity at 5 levels: 0.62 (tap water as a control), 3, 6, 9 and 12 dS m-1 was applied using sodium chloride. The results showed that salt stress caused changes in the characteristics of germination, seedling growth and antioxidant enzyme activities. With increasing in salinity levels, rate and percentage of germination as well as root length, shoot length and seedling weight was significantly decreased. However, increasing salinity levels increased the activity of antioxidant enzymes. Germination and growth in seed without pod was greater than those in seeds with pod; however, there were no significant differences between antioxidant enzyme activity; except about ascorbic peroxide that was significantly higher in seed without a pod. In general, salinity reduced germination and growth and increased antioxidant enzyme activity of annual medics. The results showed that planting seeds without pod had advantages for better germination and growth, especially under saline conditions.


Maryam Mokhtari, Sina Fallah,
Volume 6, Issue 1 (9-2019)
Abstract



Extended Abstract
Introduction: In order to take more advantage of the spring growing season, the mechanisms of germination of spring plants are of great importance at temperatures lower than the optimum temperature. Since one of the ways to reduce damage due to low temperature is enhancing the seedling antioxidant system, in this study the effects of salicylic acid and gibberellin on germination and antioxidant system of pumpkin (Cucurbita pepo) seeds were investigated under low temperatures.
Materials and Methods: A factorial experiment including four concentrations of gibberellin (0, 250, 350 and 450 mg/L), four concentrations of salicylic acid (0, 0.5, 1 and 1.5 mM) and three temperature levels (8, 11 and 14 °C) was performed with a completely randomized design within controlled conditions and six replications at Shahrekord University in 2017. The seeds were immersed in containers containing solutions of 0, 250, 350 and 450 mg/L of gibberellin and solutions with 0, 0.5, 1, and 1.5 mM salicylic acid, were placed in a growth chamber for 24 h under dark conditions at 15 °C. Then the seeds were washed at the desired temperatures, and the germination was recorded every 24 hours based on the 2 mm of radicle length. At the end of the eighth day, after the separation of normal and abnormal seedlings, 20 normal seedlings were selected from each petri dish. Following that, the germination rate, germination percentage, soluble protein, malondialdehyde, superoxide dismutase, guiacol peroxide enzyme, and catalase enzyme were measured. Comparison of means was conducted by the least significant difference test at the 0.05 probability level.
Results: The results showed that none of the treatments used at 8 °C helped germination of the plant and, therefore, 8 °C treatment was removed from the experiment. At the temperature of 11 ° C, the use of salicylic acid 1 mM and at 14 °C, the use of gibberellin 350 mg/L showed the maximum germination rate and germination percentage, compared with the control. At 11 °C, the activity of antioxidant enzymes was more affected by gibberellin hormone so that the highest activity of superoxide dismutase enzyme was observed in 350 mg/L and the highest activity of catalase and guaiacol peroxidase enzymes and the lowest amount of soluble protein were observed in gibberellin 250 mg/L. The salicylic acid hormone was more successful at 14 ° C. The salicylic acid 1.5 mM increased the activity of superoxide dismutase enzyme; and salicylic acid 0.5 mM increased the activity of catalase and salicylic acid 1 mM improved the activity of guiacol peroxidase. This hormone also succeeded in reducing the amount of soluble protein.
Conclusion: In this experiment, seedling tolerance at low temperatures was confirmed by gibberellin and salicylic acid treatments. It is generally concluded that the use of gibberellin and salicylic acid increases the activity of antioxidant enzymes and, as a result, makes pumpkin (Cucurbita pepo) seedlings tolerant to low-temperature stress, and thus, can ameliorate the effect of possible chilling on growth of this crop at the beginning of the season.
 
Highlights:
  1. Gibberellin and salicylic acid treatments make pumpkin seedling tolerant to low temperatures.
  2. Application of gibberellin and salicylic acid increases the activity of antioxidant enzymes.
  3. By using gibberellin and salicylic acid, the effect of possible chilling can be reduced at the beginning of the growing season.

Khadijeh Sourazar, Mohammad Sedghi, Raouf Seyed Sharifi,
Volume 9, Issue 1 (9-2022)
Abstract

Extended Abstract
Introduction: The germination stage ensures the durability, establishment, and final yield of plants.  The final density of plants per unit area is resulted when the planted seeds germinate fully and with adequate rate. Plants mainly undergo abiotic stresses that are a considerable constraint for agricultural production worldwide. Seed priming is one of the simplest and cheap methods to improve seed germination, acceleration of seedling growth and establishment, uniformity, reduction of flowering time, vigorous seedling production, etc which leads to improved quality and yield of crop under stressful and non-stressful conditions. This study aimed to investigate the effect of different types of priming on enzymatic and physiological changes of French bean seed under cobalt chloride stress conditions.
Materials and Methods: To examine the effect of priming on germination indices, the activity of antioxidant enzymes and proteins in French bean under cobalt chloride stress, a factorial experiment was performed in a completely randomized design with three replications. These factors included four levels: seed priming with 100 mg / l salicylic acid and mannitol, control and distilled water (no priming), and three levels of cobalt chloride stress (0, 100, and 200 mg / l).
Results: The results showed that with increasing cobalt chloride concentration, germination indices (germination rate, root length, root fresh weight, stem fresh weight and stem dry weight) decreased. However, in the pretreatment of distilled water, salicylic acid, and mannitol there was a significant increase in germination indices (mean germination time, radicle length, plumule length, fresh radicle weight, and weight plumule) was observed. The interaction effect of priming and cobalt chloride caused an increase in radicle dry weight compared to control × stress treatment. The highest values of fresh radicle weight (14.4 g), dry weight of plumule (0.27 g), and plumule length (0.17 cm) were obtained in hydro priming pretreatment. The results also showed that hormone priming under stress conditions of 200 and 100 mg / l cobalt chloride increased protein content and polyphenol oxidase activity of French bean seedlings compared with the control treatment, respectively. Osmo priming increased the activity of catalase and peroxidase enzymes under stress and non-stress conditions resulted by 200 mg / l cobalt chloride.
Conclusion: according to the results of the present study, cobalt chloride reduced some physiological and biochemical traits of French bean seeds. However, the French bean has a relatively high cobalt chloride tolerance capacity, so that it showed good tolerance to different concentrations of cobalt chloride for up to 9 days.

Highlights:
1- The effect of different concentrations of cobalt chloride and different types of priming on the germination of French bean seeds was investigated.
2- French bean seedling protein content increased under the influence of hormone priming.

Zeynab Savaedy, Abdol Mehdi Bakhshandeh, Seyed Ataollah Siadat, Amin Lotfi Jalal Abadi, Seyed Amir Moosavi,
Volume 10, Issue 2 (3-2024)
Abstract

Extended abstract
Introduction: Deterioration reduces the quality of seeds. Oilseeds like Nigella are highly susceptible to seed aging. Seed priming enhances the quality of deteriorated seeds by improving germination indices and increasing the activity of antioxidant enzymes. This research aimed to investigate the extent of damage caused by accelerated aging treatment on the germination characteristics and antioxidant enzyme activity of Nigella seeds and the possibility of mitigating the adverse effects of aging through hormonal priming with cytokinin.
Materials and methods: This research was carried out in the form of a completely random basic design with four replications in the seed technology laboratory of Khuzestan University of Agricultural Sciences and Natural Resources in 2017. The treatments included hormonal priming with cytokinin at five levels (0 (control), 10, 20, 40, and 80 m/l) for two durations (12 and 24 hours), and aging under 100% relative humidity and a temperature of 45 °C at five levels (no aging, 24, 48, 72, and 96 h).
Results: The analysis of variance results indicated that germination indices were only influenced by main and two-way effects at the 5% and 1% probability levels, while the three-way interactions, including aging, hormone concentration, and priming duration, were significant for plant growth and longitudinal and weight indices at the 1% probability level. Furthermore, it was evident that the priming treatment mitigated the negative effects of aging, with the concentration of 10 milligrams per liter of cytokinin for a duration of 12 h having the most significant impact among the hormone concentrations used on the measured traits. The highest germination percentage (88%) and the lowest germination percentage (63.33%) were observed at concentrations of 10 and 80 mg/l, respectively. The use of cytokinin at optimal concentration improved catalase activity and protein levels. The results showed that in the control conditions, the activity of the catalase enzyme was 0.76 units per mg of protein and the amount of protein was 0.51 mg/g, which reached 0.97 units per mg of protein and 0.79 mg/g with seed priming.
Conclusion: Based on the results obtained from this research, aging led to a reduction in germination indices, the activity of antioxidant enzymes, and seed protein content. The best treatment applied was cytokinin hormone priming for aged Nigella seeds at a concentration of 10 mg/l for 12 h. According to the results, the application of cytokinin at its optimal concentration (10 mg/l) improved the catalase enzyme activity and protein content. Therefore, it can be suggested that hormonal priming with cytokinin helps mitigate the adverse effects of aging in Nigella plants.

Highlights:
  1. The impact of hormonal priming with cytokinin at concentrations of 10, 20, 40, and 80 mg/L on aged Nigella seeds was investigated.
  2. The use of a concentration of 10 mg/l of cytokinin hormone for 12 hours was introduced as the best treatment.
  3. Cytokinin was introduced as a significant hormone that enhances the activity of antioxidant enzymes and physiological traits in aged Nigella seeds.

Haniyeh Saadat, Mohammad Sedghi,
Volume 11, Issue 1 (9-2024)
Abstract

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


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