Response of Sorghum Seeds to Soaking with Antioxidants (Glutathione) and Grown at Three Temperatures in Laboratory Conditions

The study aims to evaluate the pre-soaking of white corn seeds with different concentrations of glutathione under heat stress on some seed viability characteristics. The experiment was carried out in the laboratory of the Seed Examination and Certification Department. The Ministry of Agriculture, by soaking the seeds with four concentrations of glutathione (0, 50, 100, 150 mg L-1) for 12 hours and cultivating them under three temperatures (15, 25,35 °C) with the aim of knowing its effect on improving seed viability and germination strength. The experimental was carried out according to a completely randomized design (CRD) with four replicates. The results showed that the concentration of 150 mg L-1 was superior in germination speed, feather length, and peroxidase enzyme activity, as it gave these averages (79.32%, 9.57 cm, and 93.22 absorption units ml-1) respectively, the soaking treatment with a concentration of 100 mg L-1 excelled in the root length characteristic, and there was no significant difference between the concentrations in the dry weight of the seedling. The root, plumage and dry weight of the seedling gave values (81.50%, 14.62 cm and 13.30 cm 0.022 mg seedlin) respectively. The highest average temperature recorded in the activity of the biooxidase enzyme was (88.98 absorption units ml-1)


Introduction
Sorghum (Sorghum bicolor.L. Moench )of the forage and industrial cereal crops, this crop belongs to the Poaceae family, it has been classified physiologically as a plant ofC4 [1].The technology of seed revitalization is soaking the seeds with artificial or natural solutions that enhance the strength of the seeds to withstand the stresses as well as give speed and a high and homogeneous germination rate [2].It also works to start the first metabolic processes of germination without moving to full germination and is close to the point of germination [3].One of the most important problems that the crop production suffers from to White corn is the weak germination of seeds, which causes a decrease in yield, and the percentage of laboratory germination is the best possible at a temperature of 25-35°C [4].Many attempts have been made to address the failure of germination of white corn seeds without reaching comprehensive solutions.Therefore, thinking about using new methods gives the possibility of increasing the capacity of corny It is important to improve their vitality, including soaking the seeds with glutathione.As glutathione is one of the powerful antioxidants that has an important effect on maintaining the balance between oxidants and antioxidants' It is involved in many plant vital processes such as photosynthesis, DNA biosynthesis and its repair, protein biosynthesis, amino acid transfer and enzyme activity control.Oxidation, reduction, mitosis and elongation of glycosides [5].Heat stress inhibits seed germination well by activating ABA [6].Germination is affected first before all processes by heat stress, so heat stress exerts negative effects on different crops during germination although the temperature ranges vary greatly in different crops [7].The current study was conducted with the aim of addressing the failure of germination and increasing the vitality and strength of sorghum seeds through the possibility of soaking the seeds with glutathione (0,50,100,150 mg L -1 ) in improving temperature tolerance.15,25,°C)

Materials and Methods
Experiment carried outinSeed germination laboratoryaffiliateTo the Seed Examination and Certification Department The Iraqi Ministry of Agriculture -located in Baghdad Governorate in the season 2022, with the aim of studying(Response of sorghum seeds to soaking with antioxidants Glutathione, grown at three temperatures in laboratory conditions),The place where the cultivation takes place was sterilized with alcohol, as well as the tweezers, hands and all the tools used, and the planting media was moistened with water.Seeds of sorghum plants were soaked with four concentrations of glutathione (0, 50, 100 and 150 mg L -1 ) for 12 hours.,Seedswere grown on blotting paperAnd then put25 seeds on each leaf, and they were wrapped to ensure that the seeds did not fall out, and they were placed in the germinator under different levels of temperatures (15, 25, 35 °C) under laboratory conditions and the characteristics of laboratory germination were studied.The treatments were distributed according to a complete random design (CRD) for factorial experiments and with four replications, solutions were prepared according to the required concentrations, where each concentration was diluted using 1 liter of distilled water to activate the seeds with glutathione.

Studied Traits
 Germination speed: This characteristic was measured, the percentage of germination was calculated in the first count examination, four days after planting the seeds and placing them in the germinator, these data were converted into percentages according to equation.

Germination percentage% = x 100
 Root length (cm)  The length of the blade (cm) Ten normal seedlings were taken after the end of the examination period 10 days.The radicle was separated from its connection point with the seed.The length of the radicle and the length of the plumule were measured separately using a ruler, then the average of the ten readings for these two traits was taken  Dry weight of seedling (mg)  The activity of the peroxidase enzyme (absorption unit ml -1 ).One gm of fresh seedlings was taken and mashed well, and 10 ml of potassium phosphate buffer solution K2HPO4 was added, then the samples were filtered with pieces of medical gauze and then placed in a cooled centrifuge at 4 °C for half an hour at a speed of 1000 rpm.The catalase enzyme activity was estimated.according to the following equation [17]: CAT enzyme activity (Uml-1) = x 0.01

Statistical Analysis
Analysis of variance was used using the programGen Stat Releas To analyze the data statistically for the studied characteristics according to the design (CRD), the arithmetic means of the coefficients were compared and the value of the least significant difference (LSD) was used at the level of 3 probability (0.05) between the coefficients to show the nature of the differences between the coefficients.

Germination Speed(%)
It is noted from the results of Table No. ( 1) that the soaking treatment with glutathione at a concentration of 150 mg L -1 was superior to this characteristic, which gave the highest average of 79.33%,Comparing it with the control treatment that gave the lowest numbers It reached 65.67%.The reason for the superiority is that glutathione has a role in repairing the damage caused to the DNA molecule, which maintains the balance of cell work, as well as the role that leads to the regulation of some antioxidants and some plant hormones, including auxins and gibberellins [8].
Gibberellin also has a role in the seed germination process, and the secretion or formation of gibberellin and its transfer to the aleurone layer in the early stages of germination leads to cystRSeed dormancy, hydrolysis, and gene decodingand It is responsible for the synthesis of germination enzymes such as alpha-amylase and beta-amylase [9] This helps Speed The appearance of the root and the rosette [10].
As for theimpact Temperatures, the results of the same table showed that the temperature of 25 °C gave the highest mean for this characteristic.81.50%,Compared to other temperatures, especially seeds that were sown at a temperature of 15 Ca which It gave the lowest mean for that trait, which was 58.25%..attributed reasonthat The difference and superiority is that the seeds germinate in a certain range of temperatures, at which the speed of chemical reactions, the entry of oxygen and the absorption of water into the seed, and this indicates that the temperature is 25°C It stimulated increased activity of enzymes and growth regulators responsible for the germination process and increased the efficiency of the metabolic processes of the seeds ,This is consistent with what he indicated [11] In a study They obtained difference smorale incharacteristics Vitality and seed strength of wheat crop when increasing Dr Temperature ranges from 10 to 30°C,This led to rapid germination of the seed.
While the overlap values of the same table show that the seeds soaked at a concentration of 150 mg L -1 and grown at a temperature of 25 °C It gave the highest average for this trait .0090%,Compared to the seeds that were soaked with distilled water only and grown at a temperature of 15 °C, which gave the lowest mean for this trait, it reached48.00%.

Radicle Length (cm)
Results explained the Table (2) indicated that there was a significant increase in the average root length of the seeds soaked with glutathione, especially the concentration 100 mg L -1 , which gave the highest mean for this trait amounted to 12.46 cm, compared to the control treatment, which gave the lowest average of 10.34 cm.The reason is that glutathione is a powerful antioxidant that has an important effect in maintaining the balance between oxidative stress and antioxidants.It controls many plant vital processes such as photosynthesis, DNA biosynthesis and repair, protein biosynthesis, amino acid transport, enzyme control and activation, and glutathione is the main water soluble antioxidant in photosynthetic and non-photosynthetic tissues, helping to maintain the integrity of cell structures and can be used in the redox control of cell division [12].This corresponds to a study [13], If the results they reached indicated that soaking the seeds led to an increase in the rate of growth indicators, including an increase in the length of the root and for different plants that are exposed to biological stresses.
As can be seen from the data the Schedule(2)This indicates that there is a difference between the average root length of seeds grown at different temperatures, as the temperature of 25 °C gave it the highest average of 14.63 cm, compared to the temperature of 15 C, which gave the lowest average of 5.85 cm, and there was no significant difference between the two temperatures of 25 and 35 C. The reason for the superiority is attributed to that at the temperature is 25°CThere is an increase in enzymatic activity, which in turn stimulates the vital processes responsible for the decomposition of nutrients stored in the seed and its transformation into substances of simple composition in order for the fetus to benefit from it in its growth, which is positively reflected in the percentage of germination, and this is consistent with what was indicated by the mechanism [14].

Plumule Length (cm)
It is noted from the results of Table (3) that there is a significant effect between the arithmetic means of the treatments of soaking white corn seeds with glutathione in the characteristic of the length of the blade, where the concentration of 150 mgL -1 .The highest mean was 9.57 cm compared to the seeds that were soaked with distilled water only, which gave the lowest average root length characteristic of 8.08 cm, and it did not differ significantly from the concentration of 100 mgL -1, Which gave an average of 9.51 cm for the characteristic of the length of the blade.One of the reasons for the discrepancy between plant treatments is glutathione, but it is a powerful antioxidant that has a vital role in many physiological processes, including the process of growth and development, as studies indicate that GSH plays an important role in activating the antioxidant defense system, in addition to that, treatment with glutathione enhances plant growth and stress tolerance through detoxification resulting from the accumulation of ROS [15].These results agree with what was found [16] the tastiest It was shown that soaking sunflower seeds with glutathione led to an increase in both the length of the root and the plumage.
As notes from the table same This indicates that there is a difference between the average temperatures, as the temperature of 25 °C recorded the highest average of 13.30 cm, while the temperature of 15 gave the lowest average of 1.30 for this characteristic.The reason for this difference may be due to the fact that white sorghum seeds achieved the highest averages for germination at the first count Table 1This was reflected in giving strong seedlings that grow and develop better than other temperatures, and this is consistent with [17].In a study on wheat seeds, which showed that the temperature of 25-35 °C gave the highest averages in the length of the blade, in order to increase the effectiveness of the plant vital processes resulting from the activity of hormones and enzymes, and this is reflected positively in the length of the blade.As for the bilateral interaction between glutathione concentrations and temperatures It was significant among the two study factors.It is noted that the seeds soaked with a concentration of 100 mg L -1 at a temperature of 25 had the highest average overlap of 14.30 cm, while the seeds that were soaked with distilled water and grown at a higher temperature were recorded.M15The lowest value was 1.01 cm.

Seedling Dry Weight (mg)
The results of Table (4) indicate that there are no significant differences between glutathione concentrations As well as the interaction between the two factors of the study The results of Table ( 4) also show that there is a discrepancy between the average temperatures, the temperature of 25°C was superior to the other temperatures, as it gave the highest average dry weight of the seedling amounted to 0.0228 mg, while the lowest average temperature was recorded at 15°C.80.006 mg, while there was no significant difference between the degree of 25 and 35°C in the characteristic of the dry weight of the seedling.This may be attributed to the fact that the temperature of 25 °C is the optimum that encouraged the embryonic axes, which gave an increase in the characteristics of the lengths of the rootstock and the plumage, which led to an increase in the production of dry matter and thus an increase dry weight of the gesture These results are consistent with the study [18].Table 4. Effect of soaking sorghum seeds on antioxidants (Glutathione) and grown at three temperaturesin Seedling dry weight (mg).

Activity of the Peroxidase in Seedlings (AU ml -1 )
The results of Table (5) indicated that there was a significant increase in the average activity of the peroxidase enzyme (POD) when the seeds were soaked with increasing concentrations of glutathione, especially the concentration of 150 mg L -1 , which gave the highest average for this characteristic amounted to 93.23 absorption units ml -1 compared to the control treatment, which gave the lowest average of 73.71 absorption units ml -1 .The superiority in glutathione concentrations over the activity of the peroxidase enzyme is attributed to the fact that glutathione itself is a vital component of non-enzymatic antioxidants, as it preserves the components of other antioxidants and improves their activity [19].Thus, the treatment of plants with glutathione increases the activity of the antioxidant enzymes, including the peroxidase enzyme, and this is in accordance with what was indicated [20].That the treatment of different plants with glutathione led to an increase in the activities of antioxidant enzymes and resistance to vital stresses, especially heat stress.The mean temperatures differed significantly, as the temperature of 35°C recorded the highest mean of the peroxidase enzyme activity of 83.01, while the lowest mean of that characteristic at the temperature of 25°C was 78.55 ml -1 absorption units.
The activity of these enzymes increases with increasing temperatures, as noted [21] indicates that there is an initial increase in the activity of these enzymes, including the peroxidase enzyme, as the activity of this enzyme ranges to a maximum at a temperature of 35-45 degrees Celsius.With regard to the interference, it was significant in the activity of the peroxidase enzyme, as it recorded the highest average of 89.22 absorption units per ml -1 at a temperature of 35 °C with a concentration of 150 mg of glutathione, while the lowest average was recorded at a temperature of 25MWith the comparison treatment, the lowest mean was 70.114 mL -1 absorption units.Table 5.Effect of soaking sorghum seeds on antioxidants (Glutathione) and grown at three temperaturesin effectiveness enzyme POD peroxidase (AU ml -1 ).

Conclusion
We conclude from the study that the antioxidant glutathione has a role in seed germination and breaking the dormancy of the seed, especially the concentration of 150 mg, which achieved the highest averages in the studied traits.We also conclude that the best suitable temperature for germination of the white corn crop is 25°C degrees for that.

Table 1 .
Effect of soaking sorghum seeds on antioxidants (Glutathione) and grown at three temperaturesin germination rate.

Table 2 .
Effect of soaking sorghum seeds on antioxidants (Glutathione) and grown at three temperatures in radicle length.

Table 3 .
Effect of soaking sorghum seeds on antioxidants (Glutathione) and grown at three temperatures on the plumule length (cm).