University of Isfahan Journal of Plant Biological Sciences 3041-9603 16 1 2024 05 21 Effect of silicon nanoparticles on growth parameters, ascorbate and glutathione contents, and antioxidant enzyme activity in tomato under cadmium stress Effect of silicon nanoparticles on growth parameters, ascorbate and glutathione contents, and antioxidant enzyme activity in tomato under cadmium stress 1 20 29178 10.22108/ijpb.2025.142785.1373 FA Razieh Rahmatizadeh Biology Department, Faculty of Science, Urmia University, Urmia, Iran. Rashid Jamei 1Biology Department, Faculty of Science, Urmia University, Urmia, Iran. Mohammadjavad Arvin 2Horticalture Department, Faculty of Agriculture, Shahid Bahonar University of Kerman, Kerman, Iran. Journal Article 2024 09 13 Silica nanoparticles can reduce the adverse effects of abiotic stresses by modulating several physiological processes. However, there is little information about how these effects are mediated under heavy metal stress. This study investigated the role of silicon nanoparticles in mitigating the toxicity of cadmium chloride in tomatoes (Solanum lycopersicum L.) was investigated. Silicon nanoparticles were used at levels 0, 25, 50, and 100 mg/l, and cadmium chloride at three levels of 0, 100, and 200 µM. The results showed that 200 μM cadmium treatment resulted in a decrease in plant fresh weight and length, ascorbate and glutathione levels in shoots and roots, but increased cadmium, malondialdehyde, H2O2, and protein content compared to the level 0 cadmium treatment. 50 mg/l nanosilica treatment resulted in an increase in plant fresh weight and length, an increase in ascorbate and glutathione levels, and a decrease in cadmium, malondialdehyde, H2O2, and protein content compared to the level 0 nanosilica treatment. Cadmium stress increased the activity of superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, and glutathione-S-transferase, and the treatment of 50 mg/l silicon nanoparticles under cadmium stress enhanced the activity of these enzymes. The maximum increase in the activity of enzymes by silicon nanoparticles showed that these nanoparticles play a significant role in detoxifying reactive oxygen species and reducing oxidative stress induced by cadmium. Introduction Environmental pollution by heavy metals has become a serious concern. Plants more readily take up Cadmium (Cd) than other heavy metals due to their high mobility and good water solubility. The high toxicity of Cd in plants may threaten crop quality and yield. Cd induces the production of reactive oxygen species (ROS). The tripeptide glutathione (Glu-Cys-Gly), widely synthesized in plants, contains a sulfhydryl group and can quench ROS. The reduced glutathione (GSH) pool is maintained by glutathione reductase (GR), which catalyzes the NADPH-dependent reduction of the disulfide bond in the glutathione molecule. Silica (Si) is the most abundant non-metallic element in the Earth's crust after oxygen. Most plants absorb soil-soluble Si from mineral sources such as silicic or monosilicic acid. Tomatoes, one of the most popular and widely consumed crops worldwide, are significant for employing strategies to mitigate the effects of toxic substances such as Cd, thereby enhancing product quality. In this context, Alves et al. (2020) used selenium, and Naciri et al. (2021) used potassium to alleviate Cd stress in tomatoes. However, available information on the effects of Nano-SiO2 under stress conditions is limited. Therefore, this study aims to investigate how Nano-SiO2 relieves Cd stress at the morphological, biochemical, and enzymatic levels. Materials and Methods This research was conducted as a factorial experiment in triplicate, based on a completely randomized design at Urmia University. Tomato seeds purchased from Glass Garden Company were surface sterilized using 0.1% sodium hypochlorite for 15 min, rinsed, and cultured in Petri dishes. Three days after germination, the seedlings were transferred to pots containing perlite, and a half-strength micronutrient solution of Hoagland was used for irrigation and nutrition. The plants were maintained in a greenhouse with 16 hr of light and 8 hr of darkness at a temperature of 25°C during the day and 20°C at night, with a relative humidity of 70%. Nano-SiO2 was prepared at 0, 25, 50, and 100 mg/l concentrations and sonicated for 45 min. Immediately after sonication, the plants were sprayed with Nano-SiO2 once a day during the four-leaf stage for four days. Following the Nano-SiO2 treatment, the seedlings were irrigated with Hoagland solution containing CdCl2 at concentrations of 0, 100, and 200 μM for seven days. Finally, the shoots and roots were separated, frozen in liquid nitrogen, and stored at -80 °C for subsequent experiments. Malondialdehyde (MDA), hydrogen peroxide (H2O2), ascorbic acid (ASA), and dehydroascorbate (DHA) reduced glutathione (GSH (and oxidized glutathione (GSSG) levels were determined. The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), GR, and glutathione-S-transferase (GST) enzymes were also measured. All treatments were performed in triplicate, and the results were presented as mean ± SD (standard deviation). Statistical differences were evaluated using Microsoft Excel and Two Way ANOVA, followed by Duncan's multiple range test. P < 0.05 was considered to indicate a significant difference. Results and discussion The results showed that 200 μM CdCl2 decreased plant fresh weight and length, reduced ascorbate and glutathione content, and increased levels of Cd, MDA, and H2O2 compared to the 0 CdCl2 treatment. In contrast, the 50 mg/l Nano-SiO2 treatment increased plant fresh weight and length, elevated ascorbate and glutathione content, and decreased Cd, MDA, and H2O2 levels compared to the 0 Nano-SiO2 treatment. Furthermore, 200 μM CdCl2 increased protein content and antioxidant enzyme activity compared to the 0 CdCl2 treatment. The increase in antioxidant enzyme activity observed in this study under Cd stress suggests that this activity may not effectively neutralize ROS in tomatoes, as indicated by the elevated levels of MDA and H2O2. The content of MDA and H2O2 remained high despite the increase in antioxidant enzyme activity, suggesting that H2O2 accumulation exceeded the ROS scavenging capacity of the plants under Cd stress, resulting in oxidative stress due to an imbalance between ROS production and removal. However, the treatment with 50 mg/l Nano-SiO2 under 200 μM CdCl2 further increased antioxidant enzyme activity. This suggests that by enhancing antioxidant enzyme activity, Nano-SiO2 significantly reduces MDA and H2O2 levels, contributing to the stability of cell membranes and creating an environment with lower oxidative stress, as reflected in the reduction of lipid peroxidation. Consequently, these factors improve growth and increase tomato biomass under Cd stress. Conclusion The findings of this study indicate that spraying 50 mg/l of Nano-SiO2 is an effective method for enhancing tomato growth under Cd stress, as it stimulates antioxidant enzyme activity and reduces oxidative stress. Additionally, Nano-SiO2 can serve as a viable source for producing safe food products in response to food security challenges, particularly in lands contaminated with the heavy metal Cd. This method presents a suitable alternative to traditional approaches. However, field-scale studies are needed to understand these results better and confirm them. Silica nanoparticles can reduce the adverse effects of abiotic stresses by modulating several physiological processes. However, there is little information about how these effects are mediated under heavy metal stress. This study investigated the role of silicon nanoparticles in mitigating the toxicity of cadmium chloride in tomatoes (Solanum lycopersicum L.) was investigated. Silicon nanoparticles were used at levels 0, 25, 50, and 100 mg/l, and cadmium chloride at three levels of 0, 100, and 200 µM. The results showed that 200 μM cadmium treatment resulted in a decrease in plant fresh weight and length, ascorbate and glutathione levels in shoots and roots, but increased cadmium, malondialdehyde, H2O2, and protein content compared to the level 0 cadmium treatment. 50 mg/l nanosilica treatment resulted in an increase in plant fresh weight and length, an increase in ascorbate and glutathione levels, and a decrease in cadmium, malondialdehyde, H2O2, and protein content compared to the level 0 nanosilica treatment. Cadmium stress increased the activity of superoxide dismutase, ascorbate peroxidase, catalase, glutathione reductase, and glutathione-S-transferase, and the treatment of 50 mg/l silicon nanoparticles under cadmium stress enhanced the activity of these enzymes. The maximum increase in the activity of enzymes by silicon nanoparticles showed that these nanoparticles play a significant role in detoxifying reactive oxygen species and reducing oxidative stress induced by cadmium. Introduction Environmental pollution by heavy metals has become a serious concern. Plants more readily take up Cadmium (Cd) than other heavy metals due to their high mobility and good water solubility. The high toxicity of Cd in plants may threaten crop quality and yield. Cd induces the production of reactive oxygen species (ROS). The tripeptide glutathione (Glu-Cys-Gly), widely synthesized in plants, contains a sulfhydryl group and can quench ROS. The reduced glutathione (GSH) pool is maintained by glutathione reductase (GR), which catalyzes the NADPH-dependent reduction of the disulfide bond in the glutathione molecule. Silica (Si) is the most abundant non-metallic element in the Earth's crust after oxygen. Most plants absorb soil-soluble Si from mineral sources such as silicic or monosilicic acid. Tomatoes, one of the most popular and widely consumed crops worldwide, are significant for employing strategies to mitigate the effects of toxic substances such as Cd, thereby enhancing product quality. In this context, Alves et al. (2020) used selenium, and Naciri et al. (2021) used potassium to alleviate Cd stress in tomatoes. However, available information on the effects of Nano-SiO2 under stress conditions is limited. Therefore, this study aims to investigate how Nano-SiO2 relieves Cd stress at the morphological, biochemical, and enzymatic levels. Materials and Methods This research was conducted as a factorial experiment in triplicate, based on a completely randomized design at Urmia University. Tomato seeds purchased from Glass Garden Company were surface sterilized using 0.1% sodium hypochlorite for 15 min, rinsed, and cultured in Petri dishes. Three days after germination, the seedlings were transferred to pots containing perlite, and a half-strength micronutrient solution of Hoagland was used for irrigation and nutrition. The plants were maintained in a greenhouse with 16 hr of light and 8 hr of darkness at a temperature of 25°C during the day and 20°C at night, with a relative humidity of 70%. Nano-SiO2 was prepared at 0, 25, 50, and 100 mg/l concentrations and sonicated for 45 min. Immediately after sonication, the plants were sprayed with Nano-SiO2 once a day during the four-leaf stage for four days. Following the Nano-SiO2 treatment, the seedlings were irrigated with Hoagland solution containing CdCl2 at concentrations of 0, 100, and 200 μM for seven days. Finally, the shoots and roots were separated, frozen in liquid nitrogen, and stored at -80 °C for subsequent experiments. Malondialdehyde (MDA), hydrogen peroxide (H2O2), ascorbic acid (ASA), and dehydroascorbate (DHA) reduced glutathione (GSH (and oxidized glutathione (GSSG) levels were determined. The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), GR, and glutathione-S-transferase (GST) enzymes were also measured. All treatments were performed in triplicate, and the results were presented as mean ± SD (standard deviation). Statistical differences were evaluated using Microsoft Excel and Two Way ANOVA, followed by Duncan's multiple range test. P < 0.05 was considered to indicate a significant difference. Results and discussion The results showed that 200 μM CdCl2 decreased plant fresh weight and length, reduced ascorbate and glutathione content, and increased levels of Cd, MDA, and H2O2 compared to the 0 CdCl2 treatment. In contrast, the 50 mg/l Nano-SiO2 treatment increased plant fresh weight and length, elevated ascorbate and glutathione content, and decreased Cd, MDA, and H2O2 levels compared to the 0 Nano-SiO2 treatment. Furthermore, 200 μM CdCl2 increased protein content and antioxidant enzyme activity compared to the 0 CdCl2 treatment. The increase in antioxidant enzyme activity observed in this study under Cd stress suggests that this activity may not effectively neutralize ROS in tomatoes, as indicated by the elevated levels of MDA and H2O2. The content of MDA and H2O2 remained high despite the increase in antioxidant enzyme activity, suggesting that H2O2 accumulation exceeded the ROS scavenging capacity of the plants under Cd stress, resulting in oxidative stress due to an imbalance between ROS production and removal. However, the treatment with 50 mg/l Nano-SiO2 under 200 μM CdCl2 further increased antioxidant enzyme activity. This suggests that by enhancing antioxidant enzyme activity, Nano-SiO2 significantly reduces MDA and H2O2 levels, contributing to the stability of cell membranes and creating an environment with lower oxidative stress, as reflected in the reduction of lipid peroxidation. Consequently, these factors improve growth and increase tomato biomass under Cd stress. Conclusion The findings of this study indicate that spraying 50 mg/l of Nano-SiO2 is an effective method for enhancing tomato growth under Cd stress, as it stimulates antioxidant enzyme activity and reduces oxidative stress. Additionally, Nano-SiO2 can serve as a viable source for producing safe food products in response to food security challenges, particularly in lands contaminated with the heavy metal Cd. This method presents a suitable alternative to traditional approaches. However, field-scale studies are needed to understand these results better and confirm them.

https://ijpb.ui.ac.ir/article_29178_ea8d05e168bd5c685c0807e9e78638e6.pdf

University of Isfahan Journal of Plant Biological Sciences 3041-9603 16 1 2025 01 30 The dose-dependent effect of yeast extract on the content of some phenolics in the cell suspension culture of Dracocephalum polychaetum Bornm. The dose-dependent effect of yeast extract on the content of some phenolics in the cell suspension culture of Dracocephalum polychaetum Bornm. 21 38 29194 10.22108/ijpb.2025.143444.1379 FA Zohreh Vasefpour Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran Marzieh Taghizadeh Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran Seyed Hamed Moazzami Farida Department of Plant and Animal Biology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran Journal Article 2024 11 19 Dracocephalum polychaetum is a significant medicinal plant known for its antioxidant and anticancer properties. In this study, we assessed the impact of varying yeast extract (YE) doses on the levels of certain phenolic compounds in D. polychaetum cells. The experiments followed a completely randomized design with three replicates. The results indicated that all parameters considered in the treated cells showed a significant difference compared to the control. Our results indicated that the highest activities of the key enzymes PAL and TAL were observed in cells treated with 100 mg/L of YE, suggesting a response to oxidative stress induced by YE. Consequently, the highest contents of total phenol, flavonoid, quercetin, catechin, carvacrol, and thymol were found in cells treated with the same YE concentration. In addition, cells treated with 25 mg/L YE showed the highest levels of rosmarinic acid. The response to different YE concentrations was dose-dependent rather than linear. Therefore, we conclude that moderate YE concentrations (100 mg/L) effectively increase phenolic contents. Moreover, the variations in phenolic compound levels may represent a defense mechanism in D. polychaetum cells exposed to YE. Based on the correlation coefficient, the accumulation of phenolic compounds can be positively regulated by activating key enzymes, particularly the PAL enzyme, in the phenylpropanoid biosynthesis pathway in cells treated with YE. Introduction Dracocephalum polychaetum is a medicinal plant known for its potent antioxidant and anticancer properties. Extensive research has highlighted this species' applications in modern and traditional medicine, particularly its anti-inflammatory, antioxidant, antimicrobial, and anticancer properties. Phytochemical analyses have revealed a variety of phenolic compounds present in the plant. However, production of these valuable metabolites is often limited, usually making up less than 1% of the dry weight. This production is influenced by the plant's physiological and developmental stages and environmental conditions. To overcome the limitations in producing secondary metabolites, tissue and cell suspension cultures have emerged as effective biotechnological strategies. The biosynthesis of these metabolites can be significantly enhanced by applying biotic and abiotic elicitors. One commonly used elicitor is yeast extract (YE), which has been demonstrated to substantially increase the production of secondary metabolites compared to untreated controls. Despite the medicinal significance of D. polychaetum, there is a lack of experimental studies utilizing biotic elicitors to boost its metabolite production. Therefore, this study aims to investigate the effects of various concentrations of YE on the accumulation of specific phenolic compounds, as well as the activity of key enzymes involved in their biosynthetic pathways, namely phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL), within D. polychaetum cell cultures. Material and Method polychaetum seeds were germinated in MS medium supplemented with GA₃ under dark conditions at 25°C. Hypocotyl explants were cultured in MS medium containing BAP, NAA, sucrose, and agar to induce callus formation, also in complete darkness at a temperature of 23±2°C. The resulting calli were then used to establish suspension cultures maintained at 25°C on an orbital shaker and subcultured every 12 days to promote uniform cell growth. On the eighth day of cultivation, during the logarithmic growth phase, the cells were treated with varying concentrations of YE. The cells were harvested on the 13th day. The phenolic and flavonoid content and the activities of the PAL and TAL enzymes were quantified using UV-Vis spectrophotometry, while HPLC was utilized for phytochemical analysis. Statistical analyses were conducted, including Duncan's test (P ≤ 0.05) and principal component analysis (PCA), to identify significant differences and relationships among the physiological parameters. Results and Discussion The findings indicated that YE treatment significantly affected all measured parameters in D. polychaetum cells compared to the control group. The highest activities of PAL and TAL were found in cells treated with 100 mg/L YE. This suggests a strong response to the oxidative stress induced by YE. Additionally, this treatment led to the most significant accumulation of total phenols, flavonoids, quercetin, catechin, carvacrol, and thymol. Notably, the maximum content of rosmarinic acid was observed in cells treated with 25 mg/L YE. The response to YE was dose-dependent yet non-linear, with moderate concentrations (100 mg/L) proving most effective in enhancing phenolic compound production. These variations imply a defensive mechanism in D. polychaetum cells, which upregulate phenolic biosynthesis as a protective response to YE treatment. Correlation analysis further confirmed a positive association between the accumulation of phenolic compounds and the activation of PAL, underscoring the enzyme's critical role in regulating secondary metabolite production. YE is abundant in amino acids, vitamins, and minerals supporting plant growth and development. Additionally, it acts as an elicitor by triggering secondary signaling pathways by generating free radicals. These reactive molecules serve as secondary messengers, activating the phenylpropanoid pathway and stimulating the synthesis of phenolic compounds. The increased production of these potent antioxidants likely helps protect plant cells under YE-induced oxidative conditions, highlighting the potential of YE as an effective elicitor for enhancing secondary metabolite production in medicinal plants. Conclusion This study demonstrates that YE is an effective elicitor for enhancing the production of secondary metabolites in D. polychaetum. Moderate concentrations of YE (100 mg/L) significantly activated the phenylpropanoid pathway, leading to increased activity of PAL and TAL. As a result, there was an enhanced accumulation of phenolic compounds such as quercetin, catechin, and thymol. These findings highlight the potential of YE to optimize the biosynthesis of valuable medicinal metabolites, offering a sustainable strategy to address the limitations of natural metabolite production in medicinal plants. Dracocephalum polychaetum is a significant medicinal plant known for its antioxidant and anticancer properties. In this study, we assessed the impact of varying yeast extract (YE) doses on the levels of certain phenolic compounds in D. polychaetum cells. The experiments followed a completely randomized design with three replicates. The results indicated that all parameters considered in the treated cells showed a significant difference compared to the control. Our results indicated that the highest activities of the key enzymes PAL and TAL were observed in cells treated with 100 mg/L of YE, suggesting a response to oxidative stress induced by YE. Consequently, the highest contents of total phenol, flavonoid, quercetin, catechin, carvacrol, and thymol were found in cells treated with the same YE concentration. In addition, cells treated with 25 mg/L YE showed the highest levels of rosmarinic acid. The response to different YE concentrations was dose-dependent rather than linear. Therefore, we conclude that moderate YE concentrations (100 mg/L) effectively increase phenolic contents. Moreover, the variations in phenolic compound levels may represent a defense mechanism in D. polychaetum cells exposed to YE. Based on the correlation coefficient, the accumulation of phenolic compounds can be positively regulated by activating key enzymes, particularly the PAL enzyme, in the phenylpropanoid biosynthesis pathway in cells treated with YE. Introduction Dracocephalum polychaetum is a medicinal plant known for its potent antioxidant and anticancer properties. Extensive research has highlighted this species' applications in modern and traditional medicine, particularly its anti-inflammatory, antioxidant, antimicrobial, and anticancer properties. Phytochemical analyses have revealed a variety of phenolic compounds present in the plant. However, production of these valuable metabolites is often limited, usually making up less than 1% of the dry weight. This production is influenced by the plant's physiological and developmental stages and environmental conditions. To overcome the limitations in producing secondary metabolites, tissue and cell suspension cultures have emerged as effective biotechnological strategies. The biosynthesis of these metabolites can be significantly enhanced by applying biotic and abiotic elicitors. One commonly used elicitor is yeast extract (YE), which has been demonstrated to substantially increase the production of secondary metabolites compared to untreated controls. Despite the medicinal significance of D. polychaetum, there is a lack of experimental studies utilizing biotic elicitors to boost its metabolite production. Therefore, this study aims to investigate the effects of various concentrations of YE on the accumulation of specific phenolic compounds, as well as the activity of key enzymes involved in their biosynthetic pathways, namely phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL), within D. polychaetum cell cultures. Material and Method polychaetum seeds were germinated in MS medium supplemented with GA₃ under dark conditions at 25°C. Hypocotyl explants were cultured in MS medium containing BAP, NAA, sucrose, and agar to induce callus formation, also in complete darkness at a temperature of 23±2°C. The resulting calli were then used to establish suspension cultures maintained at 25°C on an orbital shaker and subcultured every 12 days to promote uniform cell growth. On the eighth day of cultivation, during the logarithmic growth phase, the cells were treated with varying concentrations of YE. The cells were harvested on the 13th day. The phenolic and flavonoid content and the activities of the PAL and TAL enzymes were quantified using UV-Vis spectrophotometry, while HPLC was utilized for phytochemical analysis. Statistical analyses were conducted, including Duncan's test (P ≤ 0.05) and principal component analysis (PCA), to identify significant differences and relationships among the physiological parameters. Results and Discussion The findings indicated that YE treatment significantly affected all measured parameters in D. polychaetum cells compared to the control group. The highest activities of PAL and TAL were found in cells treated with 100 mg/L YE. This suggests a strong response to the oxidative stress induced by YE. Additionally, this treatment led to the most significant accumulation of total phenols, flavonoids, quercetin, catechin, carvacrol, and thymol. Notably, the maximum content of rosmarinic acid was observed in cells treated with 25 mg/L YE. The response to YE was dose-dependent yet non-linear, with moderate concentrations (100 mg/L) proving most effective in enhancing phenolic compound production. These variations imply a defensive mechanism in D. polychaetum cells, which upregulate phenolic biosynthesis as a protective response to YE treatment. Correlation analysis further confirmed a positive association between the accumulation of phenolic compounds and the activation of PAL, underscoring the enzyme's critical role in regulating secondary metabolite production. YE is abundant in amino acids, vitamins, and minerals supporting plant growth and development. Additionally, it acts as an elicitor by triggering secondary signaling pathways by generating free radicals. These reactive molecules serve as secondary messengers, activating the phenylpropanoid pathway and stimulating the synthesis of phenolic compounds. The increased production of these potent antioxidants likely helps protect plant cells under YE-induced oxidative conditions, highlighting the potential of YE as an effective elicitor for enhancing secondary metabolite production in medicinal plants. Conclusion This study demonstrates that YE is an effective elicitor for enhancing the production of secondary metabolites in D. polychaetum. Moderate concentrations of YE (100 mg/L) significantly activated the phenylpropanoid pathway, leading to increased activity of PAL and TAL. As a result, there was an enhanced accumulation of phenolic compounds such as quercetin, catechin, and thymol. These findings highlight the potential of YE to optimize the biosynthesis of valuable medicinal metabolites, offering a sustainable strategy to address the limitations of natural metabolite production in medicinal plants.

https://ijpb.ui.ac.ir/article_29194_84e0db94653d9ca2d0907a5b0d4c9536.pdf

University of Isfahan Journal of Plant Biological Sciences 3041-9603 16 1 2024 05 21 Effects of salicylic acid and kinetin on some physiological, biochemical traits and the accumulation of cadmium in durum wheat Effects of salicylic acid and kinetin on some physiological, biochemical traits and the accumulation of cadmium in durum wheat 39 59 29235 10.22108/ijpb.2025.143985.1390 FA Bahar Eydi Asl Shoshtari Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran Afrasyab Rahnama Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran Payman Hassibi Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Ahvaz, Iran Parzhak Zoufan Department of Biology, Faculty of Science, Shahid Chamran University of Ahvaz, Ahvaz, Iran Journal Article 2025 01 10 To study the effects of salicylic acid and kinetin on some physiological and biochemical traits as well as the accumulation of cadmium in durum wheat, a pot experiment was carried out using a factorial experiment based on a randomized complete block design with three replications during the 2022-2023 growing season. Cadmium treatments (0 and 20 mg Cd kg-1 soil (CdCl2)) and different concentrations of kinetin and salicylic acid (0, 50, and 75 μM, kinetin; and 200 and 400 μM, salicylic acid) were assigned in plots. Cadmium treatment significantly reduced stomatal conductance, photosynthesis, transpiration, chlorophyll index, and catalase activity. However, it increased ascorbate peroxidase activity, malondialdehyde concentration, electrolyte leakage, soluble carbohydrate content, and cadmium accumulation in root and flag leaf. Foliar application of kinetin and salicylic acid mitigated the adverse effects caused by cadmium stress on physiological and biochemical parameters significantly when root and flag leaf cadmium concentrations decreased compared to the cadmium treatment. Catalase and ascorbate peroxidase activity increased in response to salicylic acid and kinetin treatment. Hence, a decrease in lipid peroxidation and malondialdehyde concentrations was observed. The optimum hormone concentrations needed to exhibit a considerable increase in studied traits were 50 μM and 400 μM salicylic acid, particularly in cadmium treatments. Foliar application of kinetin alleviated symptoms of the cadmium treatments by enhancing the activities of antioxidant enzymes and photosynthetic properties compared with individual cadmium treatments. Overall, these findings showed that foliar application of kinetin and salicylic acid can be considered a strategy to enhance the performance of wheat cultivars in soil contaminated with cadmium. Introduction Cadmium contamination of soil and food crops is one of the most serious environmental problems in recent years, and it has resulted from industrialization, wastewater irrigation, and extensive agricultural systems. High concentrations of cadmium in the soil can potentially threaten human health because it can be easily absorbed and accumulated in different parts of crops such as the root, stem, leaf, and grain. Finally, it can enter the food chain and enter the human body. Plants respond to the presence of cadmium in the soil. Cadmium influences morphological, physiological, biochemical, and structural processes and inhibits plant growth and crop production. Cadmium toxicity severely reduces the growth and yield traits of plants. Cadmium toxicity is caused by changes in the concentration of nutrients in roots and leaves, the formation of reactive oxygen species, and a decrease in transpiration, photosynthesis rate, and chlorophyll concentration, which subsequently reduces crop productivity. Plant hormones, including salicylic acid and kinetin, are crucial in responding to cadmium toxicity. Exogenous treatment with salicylic acid and kinetin alleviates the effects of cadmium toxicity in plants exposed to cadmium. This study aimed to explore optimum hormone concentrations in enhancing cadmium tolerance at wheat plants' physiological and biochemical levels. Materials and Methods To study the effects of salicylic acid and kinetin on some physiological and biochemical traits as well as the accumulation of cadmium in roots and leaves of durum wheat, a pot experiment was carried out using a factorial experiment based on a randomized complete block design with three replications during the 2022-2023 growing season. Cadmium treatments (0 and 20 mg Cd kg-1 soil (CdCl2)) and different concentrations of kinetin and salicylic acid (0, 50, and 75 μM, kinetin; and 200 and 400 μM, salicylic acid) were assigned in plots. The study site was located at the research farm of Shahid Chamran University of Ahvaz, Iran. At first, the soil needed for the experiment was weighed. The content of Cd2+ (mg kg-1) in the soil was calculated according to the dry weight of the soil, and CdCl2 was sprayed close to the soil surface in the form of the solution. Cadmium was thoroughly mixed with the soil placed into each pot. Hormonal treatments were applied at the beginning of stem elongation (stage 33 of the BBCH scale). The plants were grown under natural environmental conditions. Plants were watered with sufficient water until the end of the experiment. The data regarding stomatal conductance, photosynthesis rate, transpiration, chlorophyll index, catalase and ascorbate peroxidase activity, malondialdehyde concentration, soluble carbohydrate content, and cadmium accumulation in roots and flag leaf was recorded. The transfer factor was computed as the ratio of the cadmium concentration in leaves and roots. Results and Discussion The results showed a significant difference among cadmium treatments regarding the most studied traits. Cadmium treatment significantly reduced stomatal conductance, photosynthesis, transpiration, chlorophyll index, and catalase activity. However, it increased ascorbate peroxidase activity, malondialdehyde concentration, electrolyte leakage, soluble carbohydrate content, and cadmium accumulation in root and flag leaf. Foliar application of kinetin and salicylic acid mitigated the adverse effects caused by cadmium stress on physiological and biochemical parameters significantly when root and flag leaf cadmium concentrations decreased compared to the cadmium treatment. Cadmium caused a significant increase in flag leaf cadmium concentrations by 31 times compared to control, while the increase in flag leaf cadmium concentrations at 50 and 75 μM, kinetin; and 200 and 400 μM, salicylic acid treatments were by 18, 19, 17 and 20 times, respectively, when compared to cadmium-deficient plants. Catalase and ascorbate peroxidase activity increased in response to salicylic acid and kinetin treatment. Hence, a decrease in lipid peroxidation and malondialdehyde concentrations was observed. Hormonal treatments of 50 and 75 μM, kinetin, and 200 and 400 μM, salicylic acid reduced transfer factor by 21, 24, 24 and 27 %, respectively, compared to hormone-deficient plants. Conclusion Overall, the results of this experiment showed that the optimum hormone concentrations needed to exhibit a considerable increase in studied traits were 50 μM kinetin and 400 μM salicylic acid; remarkably, in cadmium treatments, foliar application of kinetin and salicylic acid alleviated symptoms of the cadmium treatments by enhancing the activity of antioxidant enzymes and photosynthetic properties compared with individual cadmium treatment. Moreover, foliar application of kinetin and salicylic acid can be considered a strategy to enhance the performance of wheat cultivars in soil contaminated with cadmium. To study the effects of salicylic acid and kinetin on some physiological and biochemical traits as well as the accumulation of cadmium in durum wheat, a pot experiment was carried out using a factorial experiment based on a randomized complete block design with three replications during the 2022-2023 growing season. Cadmium treatments (0 and 20 mg Cd kg-1 soil (CdCl2)) and different concentrations of kinetin and salicylic acid (0, 50, and 75 μM, kinetin; and 200 and 400 μM, salicylic acid) were assigned in plots. Cadmium treatment significantly reduced stomatal conductance, photosynthesis, transpiration, chlorophyll index, and catalase activity. However, it increased ascorbate peroxidase activity, malondialdehyde concentration, electrolyte leakage, soluble carbohydrate content, and cadmium accumulation in root and flag leaf. Foliar application of kinetin and salicylic acid mitigated the adverse effects caused by cadmium stress on physiological and biochemical parameters significantly when root and flag leaf cadmium concentrations decreased compared to the cadmium treatment. Catalase and ascorbate peroxidase activity increased in response to salicylic acid and kinetin treatment. Hence, a decrease in lipid peroxidation and malondialdehyde concentrations was observed. The optimum hormone concentrations needed to exhibit a considerable increase in studied traits were 50 μM and 400 μM salicylic acid, particularly in cadmium treatments. Foliar application of kinetin alleviated symptoms of the cadmium treatments by enhancing the activities of antioxidant enzymes and photosynthetic properties compared with individual cadmium treatments. Overall, these findings showed that foliar application of kinetin and salicylic acid can be considered a strategy to enhance the performance of wheat cultivars in soil contaminated with cadmium. Introduction Cadmium contamination of soil and food crops is one of the most serious environmental problems in recent years, and it has resulted from industrialization, wastewater irrigation, and extensive agricultural systems. High concentrations of cadmium in the soil can potentially threaten human health because it can be easily absorbed and accumulated in different parts of crops such as the root, stem, leaf, and grain. Finally, it can enter the food chain and enter the human body. Plants respond to the presence of cadmium in the soil. Cadmium influences morphological, physiological, biochemical, and structural processes and inhibits plant growth and crop production. Cadmium toxicity severely reduces the growth and yield traits of plants. Cadmium toxicity is caused by changes in the concentration of nutrients in roots and leaves, the formation of reactive oxygen species, and a decrease in transpiration, photosynthesis rate, and chlorophyll concentration, which subsequently reduces crop productivity. Plant hormones, including salicylic acid and kinetin, are crucial in responding to cadmium toxicity. Exogenous treatment with salicylic acid and kinetin alleviates the effects of cadmium toxicity in plants exposed to cadmium. This study aimed to explore optimum hormone concentrations in enhancing cadmium tolerance at wheat plants' physiological and biochemical levels. Materials and Methods To study the effects of salicylic acid and kinetin on some physiological and biochemical traits as well as the accumulation of cadmium in roots and leaves of durum wheat, a pot experiment was carried out using a factorial experiment based on a randomized complete block design with three replications during the 2022-2023 growing season. Cadmium treatments (0 and 20 mg Cd kg-1 soil (CdCl2)) and different concentrations of kinetin and salicylic acid (0, 50, and 75 μM, kinetin; and 200 and 400 μM, salicylic acid) were assigned in plots. The study site was located at the research farm of Shahid Chamran University of Ahvaz, Iran. At first, the soil needed for the experiment was weighed. The content of Cd2+ (mg kg-1) in the soil was calculated according to the dry weight of the soil, and CdCl2 was sprayed close to the soil surface in the form of the solution. Cadmium was thoroughly mixed with the soil placed into each pot. Hormonal treatments were applied at the beginning of stem elongation (stage 33 of the BBCH scale). The plants were grown under natural environmental conditions. Plants were watered with sufficient water until the end of the experiment. The data regarding stomatal conductance, photosynthesis rate, transpiration, chlorophyll index, catalase and ascorbate peroxidase activity, malondialdehyde concentration, soluble carbohydrate content, and cadmium accumulation in roots and flag leaf was recorded. The transfer factor was computed as the ratio of the cadmium concentration in leaves and roots. Results and Discussion The results showed a significant difference among cadmium treatments regarding the most studied traits. Cadmium treatment significantly reduced stomatal conductance, photosynthesis, transpiration, chlorophyll index, and catalase activity. However, it increased ascorbate peroxidase activity, malondialdehyde concentration, electrolyte leakage, soluble carbohydrate content, and cadmium accumulation in root and flag leaf. Foliar application of kinetin and salicylic acid mitigated the adverse effects caused by cadmium stress on physiological and biochemical parameters significantly when root and flag leaf cadmium concentrations decreased compared to the cadmium treatment. Cadmium caused a significant increase in flag leaf cadmium concentrations by 31 times compared to control, while the increase in flag leaf cadmium concentrations at 50 and 75 μM, kinetin; and 200 and 400 μM, salicylic acid treatments were by 18, 19, 17 and 20 times, respectively, when compared to cadmium-deficient plants. Catalase and ascorbate peroxidase activity increased in response to salicylic acid and kinetin treatment. Hence, a decrease in lipid peroxidation and malondialdehyde concentrations was observed. Hormonal treatments of 50 and 75 μM, kinetin, and 200 and 400 μM, salicylic acid reduced transfer factor by 21, 24, 24 and 27 %, respectively, compared to hormone-deficient plants. Conclusion Overall, the results of this experiment showed that the optimum hormone concentrations needed to exhibit a considerable increase in studied traits were 50 μM kinetin and 400 μM salicylic acid; remarkably, in cadmium treatments, foliar application of kinetin and salicylic acid alleviated symptoms of the cadmium treatments by enhancing the activity of antioxidant enzymes and photosynthetic properties compared with individual cadmium treatment. Moreover, foliar application of kinetin and salicylic acid can be considered a strategy to enhance the performance of wheat cultivars in soil contaminated with cadmium.

https://ijpb.ui.ac.ir/article_29235_c846ce01de49fdf572372f68a8c3fdc7.pdf

University of Isfahan Journal of Plant Biological Sciences 3041-9603 16 1 2024 05 21 Investigation of Some Strategies to Overcome Hyperhydration in Cucumber Regenerated Plants from Anthers Investigation of Some Strategies to Overcome Hyperhydration in Cucumber Regenerated Plants from Anthers 61 75 29262 10.22108/ijpb.2025.144088.1392 FA Abouzar Asadi Department of Plant Genetic and Production Engineering, Faculty of Agriculture and Natural Recourses, Isfahan Branch (Khorasgan), Islamic Azad University, Isfahan, Iran. Plant Improvement and Seed Production Center, Isfahan Branch (Khorasgan), Islamic Azad University, Isfahan, Iran. 0000-0001-6461-3277 Alireza Zebarjadi Department of Production Engineering and Plant Genetics, Faculty of Science and Agricultural Engineering, Razi University, Kermanshah, Iran. Journal Article 2025 01 19 Hyperhydration is one of the most common physiological disorders in vitro conditions, leading to specific anatomical, morphological, physiological, and metabolic alterations. This study examines various methods to combat hyperhydration in regenerated plants derived from cucumber anthers cultures. The experiments included reducing relative humidity in culture vessels, decreasing the frequency of subculturing, lowering cytokinin concentrations, inducing root formation, increasing light intensity, bottom cooling, and altering the concentration of culture medium components. All experiments were conducted in a completely randomized design with three replications. Results indicated significant differences among treatments at the 1% level (P ≤ 0.01). Root induction reduced hyperhydration by 70%, decreased cytokinin concentrations by 35%, increased light intensity by 30%, reduced subculture frequency to every 21 days by 25%, lowered relative humidity in culture vessels by 20%, bottom cooling by 2%, and altering the concentration of culture medium components by 1%. The findings suggested that the impact of one or multiple methods in mitigating hyperhydration may not always be consistent and depends on the genotype and plant species. Introduction Cucumber, an important plant in horticulture, is widely studied for its biological processes, including sex determination and gene transfer. Tissue culture techniques are crucial for various biotechnological studies but face challenges like hyperhydration, a prevalent physiological disorder in vitro cultivation. Hyperhydration leads to anatomical, morphological, physiological, and metabolic disruptions, affecting plant quality and acclimatization. Symptoms include altered cell structures, reduced chlorophyll, and compromised enzymatic activity. Mitigating hyperhydration involves adjusting environmental conditions and hormonal treatments, although not all methods are universally effective, highlighting the need for species-specific approaches in addressing this issue. Materials and Methods The preliminary stages of the experiment and cucumber plant regeneration from anther culture were carried out based on Asadi et al. (2018). After inducing regeneration, samples affected by hyperhydricity were separated from the other explants and placed in MS with 30 g/l sucrose and a pH of 5.75, according to Table 1. The experiment used a completely randomized design with three replications (each culture flask as one replication). In this study, eight treatments reported in Table 1 were investigated. After applying the treatments, the number of plants with altered status was counted and recorded. Analysis of variance (ANOVA) was used for statistical analysis, and the least significant difference (LSD) test was applied for comparing means. Excel 2016 and SPSS 26 software were used for data analysis. Table 1- Different treatments to overcome the hyperhydricity in cucumbers regenerated plants by anther culture Results and Discussion The experiment demonstrated significant differences among treatments used to control and improve hyperhydricity in regenerated cucumber plantlets at a 1% significance level (P ≤ 0.01). The comparison of means indicated that rooting was the most effective method for significantly improving plant health. Increasing light intensity and reducing subculture frequency also played important roles in enhancing plant growth conditions. Decreasing BAP concentration and relative humidity inside the culture vessels also had positive effects. Conversely, treatments such as bottom ventilation and altering other growth medium components did not show significant effects. Two methods were employed to reduce relative humidity: increasing agar concentration and using containers with filter lids. These methods reduced hyperhydricity by approximately 10%, although no significant difference was observed from the control group. Increasing the subculture frequency increased hyperhydricity, while reducing the frequency decreased hyperhydricity rates. High concentrations of BAP contributed to increased hyperhydricity. Regenerated plants from combinations of 3 and 4 mg/L BAP with 0.05 mg/L NAA showed a 30% improvement when transferred to the plant growth regulator-free medium. Rooting with 0.2 mg/L IAA significantly reduced hyperhydricity by about 70%. Increasing the light intensity to 50 µmol/m²/s reduced hyperhydricity in 30% of regenerated plants. However, bottom ventilation, while showing improvement in 2% of samples, did not significantly differ from the control. Conclusion Overall, the results indicate that inducing rooting, precise regulation of growth regulators' type and concentration, increasing light intensity, reducing subculture frequency, and lowering relative humidity inside the culture vessels can significantly improve hyperhydricity. However, bottom ventilation and altering other growth medium components did not significantly impact. These findings suggest that achieving complete elimination of hyperhydricity may require additional methods depending on the genotype and species of the plant, necessitating further research in this area. Hyperhydration is one of the most common physiological disorders in vitro conditions, leading to specific anatomical, morphological, physiological, and metabolic alterations. This study examines various methods to combat hyperhydration in regenerated plants derived from cucumber anthers cultures. The experiments included reducing relative humidity in culture vessels, decreasing the frequency of subculturing, lowering cytokinin concentrations, inducing root formation, increasing light intensity, bottom cooling, and altering the concentration of culture medium components. All experiments were conducted in a completely randomized design with three replications. Results indicated significant differences among treatments at the 1% level (P ≤ 0.01). Root induction reduced hyperhydration by 70%, decreased cytokinin concentrations by 35%, increased light intensity by 30%, reduced subculture frequency to every 21 days by 25%, lowered relative humidity in culture vessels by 20%, bottom cooling by 2%, and altering the concentration of culture medium components by 1%. The findings suggested that the impact of one or multiple methods in mitigating hyperhydration may not always be consistent and depends on the genotype and plant species. Introduction Cucumber, an important plant in horticulture, is widely studied for its biological processes, including sex determination and gene transfer. Tissue culture techniques are crucial for various biotechnological studies but face challenges like hyperhydration, a prevalent physiological disorder in vitro cultivation. Hyperhydration leads to anatomical, morphological, physiological, and metabolic disruptions, affecting plant quality and acclimatization. Symptoms include altered cell structures, reduced chlorophyll, and compromised enzymatic activity. Mitigating hyperhydration involves adjusting environmental conditions and hormonal treatments, although not all methods are universally effective, highlighting the need for species-specific approaches in addressing this issue. Materials and Methods The preliminary stages of the experiment and cucumber plant regeneration from anther culture were carried out based on Asadi et al. (2018). After inducing regeneration, samples affected by hyperhydricity were separated from the other explants and placed in MS with 30 g/l sucrose and a pH of 5.75, according to Table 1. The experiment used a completely randomized design with three replications (each culture flask as one replication). In this study, eight treatments reported in Table 1 were investigated. After applying the treatments, the number of plants with altered status was counted and recorded. Analysis of variance (ANOVA) was used for statistical analysis, and the least significant difference (LSD) test was applied for comparing means. Excel 2016 and SPSS 26 software were used for data analysis. Table 1- Different treatments to overcome the hyperhydricity in cucumbers regenerated plants by anther culture Results and Discussion The experiment demonstrated significant differences among treatments used to control and improve hyperhydricity in regenerated cucumber plantlets at a 1% significance level (P ≤ 0.01). The comparison of means indicated that rooting was the most effective method for significantly improving plant health. Increasing light intensity and reducing subculture frequency also played important roles in enhancing plant growth conditions. Decreasing BAP concentration and relative humidity inside the culture vessels also had positive effects. Conversely, treatments such as bottom ventilation and altering other growth medium components did not show significant effects. Two methods were employed to reduce relative humidity: increasing agar concentration and using containers with filter lids. These methods reduced hyperhydricity by approximately 10%, although no significant difference was observed from the control group. Increasing the subculture frequency increased hyperhydricity, while reducing the frequency decreased hyperhydricity rates. High concentrations of BAP contributed to increased hyperhydricity. Regenerated plants from combinations of 3 and 4 mg/L BAP with 0.05 mg/L NAA showed a 30% improvement when transferred to the plant growth regulator-free medium. Rooting with 0.2 mg/L IAA significantly reduced hyperhydricity by about 70%. Increasing the light intensity to 50 µmol/m²/s reduced hyperhydricity in 30% of regenerated plants. However, bottom ventilation, while showing improvement in 2% of samples, did not significantly differ from the control. Conclusion Overall, the results indicate that inducing rooting, precise regulation of growth regulators' type and concentration, increasing light intensity, reducing subculture frequency, and lowering relative humidity inside the culture vessels can significantly improve hyperhydricity. However, bottom ventilation and altering other growth medium components did not significantly impact. These findings suggest that achieving complete elimination of hyperhydricity may require additional methods depending on the genotype and species of the plant, necessitating further research in this area.

https://ijpb.ui.ac.ir/article_29262_ac746d62716688c6cbbcbbcf2b5e6751.pdf

University of Isfahan Journal of Plant Biological Sciences 3041-9603 16 1 2024 05 21 Estimation of genetic factors and the response of different sugar beet (Beta vulgaris L.) cultivars to low temperatures at the maturity stage Estimation of genetic factors and the response of different sugar beet (Beta vulgaris L.) cultivars to low temperatures at the maturity stage 77 93 29263 10.22108/ijpb.2025.141919.1368 FA Mehdi Jalilian Department of Agronomy and Plant Breeding, Yasouj University, Yasouj, Iran Massoud Dehdari Department of Agronomy and Plant Breeding, Yasouj University, Yasouj, Iran Reza Amiri Fahliani Department of Agronomy and Plant Breeding, Yasouj University, Yasouj, Iran Mohsen Movahhedi Dehnavi Department of Agronomy and Plant Breeding, Yasouj University, Yasouj, Iran Journal Article 2024 06 21 Sugar beet has a high yield potential, but various stresses, including cold, reduce its yield worldwide. To investigate the cold tolerance of common sugar beet cultivars in the maturity stage, an experiment was carried out at Yasouj University in 2020. In this research, ten sugar beet cultivars (Karaji, SBSI-005, Shirin, Rastad, Anakonda, Dorotea, Merac, Antik, Zarghan, and Persia.) were exposed to four temperature levels, including (0, 5, 10, and 25 (control) ℃) at maturity stage. The experiment was performed at each temperature level based on a completely randomized design with three repetitions. The results of the analysis of variance showed that the effect of temperature for all measured traits, the effect of genotype for all characteristics except root diameter, electrolyte leakage, and Fv/Fm, and the interaction of temperature and genotype for all measured traits except electrolyte leakage were significant. Therefore, the cultivars studied responded differently to the different temperature levels studied. The highest reduction of the characteristics at 0˚C compared to the control (25˚C) was related to the shoot dry weight by 55%, and the highest increase was related to the leaf proline content by 58%. Sugar weight had a positive and significant genetic correlation with the traits of root weight, soluble sugar, sugar content, and shoot dry weight. At the same time, it showed a negative correlation with the root length and SPAD number traits. The three-dimensional scatter plot identified Persia and Antic cultivars as more tolerant to cold stress than other cultivars. The results of this study provide valuable information to sugar beet breeders to improve cold tolerance. Introduction Sugar beet (Beta vulgaris L.) is one of the twelve main plants that provide food for the world's people. Sugar beet has a high yield potential, but various stresses, including cold, reduce its yield worldwide. Cold is one of the most important abiotic stresses that limit plant growth, production, and geographical distribution. The cold at the end of the growing season reduces the yield of sugar beet and has a negative effect on its quality. Therefore, it is of great theoretical and practical importance to explore the mechanism of cold tolerance and to improve it in susceptible sugar beet genotypes. Most of the previous studies have been conducted regarding the effect of cold stress on physiological aspects of sugar beet traits at the seedling stage. Our previous study studied the effect of cold stress on morpho-physiological traits of ten common sugar beet cultivars. There is little information about the genetic aspects of cold tolerance of common sugar beet cultivars at the maturity stage in Iran. This research investigated the genetic response of sugar beet cultivars to cold stress and the genetic relationships between their important traits in cold stress conditions at the maturity stage. Materials and Methods To study the cold tolerance of common sugar beet cultivars in the maturity stage, an experiment was carried out at Yasouj University in 2020. In this research, ten sugar beet cultivars (Karaji, SBSI-005, Shirin, Rastad, Anakonda, Dorotea, Merac, Antik, Zarghan, and Persia.) were exposed to four temperature levels, including (0, 5, 10, and 25 (control) ℃) at maturity stage. The experiment was performed at each temperature level based on a completely randomized design with three repetitions. Ten days after the cold treatment application, important morpho-physiological traits, including crown height, plant height, shoot dry weight, root diameter, root length, root weight, proline content, soluble sugar, SPAD value, electrolyte leakage, FV/FM ratio, sugar content, and sugar weight were measured. Combined variance analysis was performed, and environmental, genotypic, and phenotypic variances were calculated. Genotypic and phenotypic coefficients of variation and broad-sense heritability were calculated. The Pearson correlation coefficient between the measured traits was calculated, and the relationships among variables were interpreted. Factor analysis was done, and the most important first components were interpreted. The three-dimensional scatter plot of the distribution of genotypes was drawn based on the first three factor scores. Genotypes were classified according to their response to cold stress. Results and Discussion The results of the combined analysis of variance showed that the effect of temperature for all measured traits, the effect of genotype for all characteristics except root diameter, electrolyte leakage, and Fv/Fm, and the interaction of temperature and genotype for all measured traits except electrolyte leakage were significant. The highest reduction of the characteristics at 0˚C compared to the control (25˚C) was related to the shoot dry weight by 55%, and the highest increase was related to the leaf proline content by 58%. Broad-sense heritability of root diameter, electrolyte leakage, and Fv/Fm was over 50%, indicating less effect of environmental factors. Proline content and total soluble sugar had a maximum genetic coefficient of variation. In contrast, sugar weight had a positive and significant genetic correlation with the traits of root weight, soluble sugar, sugar content, and shoot dry weight. At the same time, it showed a negative correlation with the root length and SPAD number traits. So, these traits can be used in indirect selection to improve sugar weight. Factors analysis in cold conditions identified the first two factors related to cold tolerance and the third factor related to cold sensitivity. The three-dimensional scatter plot identified Persia and Antic cultivars as more tolerant to cold stress than other cultivars. The results of this study provide valuable information to sugar beet breeders to improve cold tolerance. Conclusion Based on the results of this research, high genetic diversity was observed for traits related to cold tolerance in sugar beet. In addition, genetic relationships among important sugar beet traits in cold conditions show that some characteristics can be used in indirect selection to improve cold tolerance in sugar beet. Some traits had more than 50% heritability, which can be considered in sugar beet breeding programs. There was a relationship between cold tolerance in the vegetative stage and the maturity stage. Therefore, it is possible to improve cold tolerance in the early stages of growth. Sugar beet has a high yield potential, but various stresses, including cold, reduce its yield worldwide. To investigate the cold tolerance of common sugar beet cultivars in the maturity stage, an experiment was carried out at Yasouj University in 2020. In this research, ten sugar beet cultivars (Karaji, SBSI-005, Shirin, Rastad, Anakonda, Dorotea, Merac, Antik, Zarghan, and Persia.) were exposed to four temperature levels, including (0, 5, 10, and 25 (control) ℃) at maturity stage. The experiment was performed at each temperature level based on a completely randomized design with three repetitions. The results of the analysis of variance showed that the effect of temperature for all measured traits, the effect of genotype for all characteristics except root diameter, electrolyte leakage, and Fv/Fm, and the interaction of temperature and genotype for all measured traits except electrolyte leakage were significant. Therefore, the cultivars studied responded differently to the different temperature levels studied. The highest reduction of the characteristics at 0˚C compared to the control (25˚C) was related to the shoot dry weight by 55%, and the highest increase was related to the leaf proline content by 58%. Sugar weight had a positive and significant genetic correlation with the traits of root weight, soluble sugar, sugar content, and shoot dry weight. At the same time, it showed a negative correlation with the root length and SPAD number traits. The three-dimensional scatter plot identified Persia and Antic cultivars as more tolerant to cold stress than other cultivars. The results of this study provide valuable information to sugar beet breeders to improve cold tolerance. Introduction Sugar beet (Beta vulgaris L.) is one of the twelve main plants that provide food for the world's people. Sugar beet has a high yield potential, but various stresses, including cold, reduce its yield worldwide. Cold is one of the most important abiotic stresses that limit plant growth, production, and geographical distribution. The cold at the end of the growing season reduces the yield of sugar beet and has a negative effect on its quality. Therefore, it is of great theoretical and practical importance to explore the mechanism of cold tolerance and to improve it in susceptible sugar beet genotypes. Most of the previous studies have been conducted regarding the effect of cold stress on physiological aspects of sugar beet traits at the seedling stage. Our previous study studied the effect of cold stress on morpho-physiological traits of ten common sugar beet cultivars. There is little information about the genetic aspects of cold tolerance of common sugar beet cultivars at the maturity stage in Iran. This research investigated the genetic response of sugar beet cultivars to cold stress and the genetic relationships between their important traits in cold stress conditions at the maturity stage. Materials and Methods To study the cold tolerance of common sugar beet cultivars in the maturity stage, an experiment was carried out at Yasouj University in 2020. In this research, ten sugar beet cultivars (Karaji, SBSI-005, Shirin, Rastad, Anakonda, Dorotea, Merac, Antik, Zarghan, and Persia.) were exposed to four temperature levels, including (0, 5, 10, and 25 (control) ℃) at maturity stage. The experiment was performed at each temperature level based on a completely randomized design with three repetitions. Ten days after the cold treatment application, important morpho-physiological traits, including crown height, plant height, shoot dry weight, root diameter, root length, root weight, proline content, soluble sugar, SPAD value, electrolyte leakage, FV/FM ratio, sugar content, and sugar weight were measured. Combined variance analysis was performed, and environmental, genotypic, and phenotypic variances were calculated. Genotypic and phenotypic coefficients of variation and broad-sense heritability were calculated. The Pearson correlation coefficient between the measured traits was calculated, and the relationships among variables were interpreted. Factor analysis was done, and the most important first components were interpreted. The three-dimensional scatter plot of the distribution of genotypes was drawn based on the first three factor scores. Genotypes were classified according to their response to cold stress. Results and Discussion The results of the combined analysis of variance showed that the effect of temperature for all measured traits, the effect of genotype for all characteristics except root diameter, electrolyte leakage, and Fv/Fm, and the interaction of temperature and genotype for all measured traits except electrolyte leakage were significant. The highest reduction of the characteristics at 0˚C compared to the control (25˚C) was related to the shoot dry weight by 55%, and the highest increase was related to the leaf proline content by 58%. Broad-sense heritability of root diameter, electrolyte leakage, and Fv/Fm was over 50%, indicating less effect of environmental factors. Proline content and total soluble sugar had a maximum genetic coefficient of variation. In contrast, sugar weight had a positive and significant genetic correlation with the traits of root weight, soluble sugar, sugar content, and shoot dry weight. At the same time, it showed a negative correlation with the root length and SPAD number traits. So, these traits can be used in indirect selection to improve sugar weight. Factors analysis in cold conditions identified the first two factors related to cold tolerance and the third factor related to cold sensitivity. The three-dimensional scatter plot identified Persia and Antic cultivars as more tolerant to cold stress than other cultivars. The results of this study provide valuable information to sugar beet breeders to improve cold tolerance. Conclusion Based on the results of this research, high genetic diversity was observed for traits related to cold tolerance in sugar beet. In addition, genetic relationships among important sugar beet traits in cold conditions show that some characteristics can be used in indirect selection to improve cold tolerance in sugar beet. Some traits had more than 50% heritability, which can be considered in sugar beet breeding programs. There was a relationship between cold tolerance in the vegetative stage and the maturity stage. Therefore, it is possible to improve cold tolerance in the early stages of growth.

https://ijpb.ui.ac.ir/article_29263_01ae0a7ee0e4a8153e719cdad65721e3.pdf