Cell and Tissue Journal

Abstract Aim: Potato (Solanum tuberosum L.) is a crop belongs to the Solanaceae family. It is the fourth strategic crops following wheat, rice, and corn. Salicylic acid or orthohydroxybenzoic acid, act as a regulator that can regulate physiological, biochemical and signaling functions in plant metabolic processes. Aim: Salicylic acid as a growth regulator can interact with auxin and gibberellin hormones and effectively induce growth and metabolic processes in potato plants. Potato is one of the most important agricultural plants and in vitro culture can be used as a model in laboratory conditions. The aim of this study is to investigate the effect of salicylic acid on growth indicators and its interaction with other hormones.
Material and method: In this study, potato seedlings with uniform growth were grown on MS culture medium with concentrations of zero, 0.1, 10 and 100 μM salicylic acid. The seedlings were placed in the growth room under light conditions of 16 hours of light and 8 hours of darkness at room temperature. After four weeks, the grown seedlings were used for wet weight, dry weight, shoot and root length, photosynthetic pigments, auxin and gibberellin hormones content were measured. The statistical analysis was performed using SPSS software.
Results: According to the data, growth parameters in the samples treated with salicylic acid showed similar patter. Our results showed that relative water capacity, root and shoot length and pigments under 0.1, 1 and 10 μM significantly increased compared to control samples. While at the concentration of 100 μM, a decreasing trend was observed in the growth parameters and showed a significant decrease compared to the control samples. In this study, the maximum values ​​in all growth parameters were obtained under the concentration of 10 μM salicylic acid. Furthermore, based on the results, the concentration of 0.1 μM salicylic acid had no significant difference on gibberellin hormone content. While the gibberellin hormone content under salicylic acid treatment at concentrations of 1 and 10 μM significantly increased compared to the control sample, and the maximum level was observed at 10 μM. The concentration of 100 μM, unlike the other concentrations, showed a significant difference compared to the control sample with a decreasing trend. Also the results in auxin levels showed a similar pattern with growth parameters and gibberellin hormone. The auxin levels showed a significant increase under the concentrations of 1, 10 and 100 μM compared to the control sample, and the maximum levels were observed at the concentration of 10 μM. However, concentrations of 1 and 10 μM did not show significant differences. Similar to the results of gibberellin hormone, auxin hormone showed a significant difference under the concentration of 100 μM with a decreasing trend compared to the control sample.
 Conclusion: It seems that salicylic acid increased in low concentrations due to the direct effects on the metabolic and enzymatic processes of growth parameters, photosynthetic pigments, and auxin and gibberellin content. On the other hand, at high concentrations, the growth parameters were inhibited due to the high accumulation of reactive oxygen species produced by salicylic acid and the resulting oxidative stress.
 

Abstract Aim: Potato (Solanum tuberosum L.) is a key crop within the Solanaceae family and ranks as the most significant non-cereal crop globally following major staples such as wheat, rice, and corn. Potatoes can reproduce sexually and asexually via tubers, and plant tissue culture is emerging as an effective method for vegetative propagation, addressing the increasing global demand for agricultural products. Ethylene, a critical plant growth regulator, influences various physiological processes including growth and development. During in vitro culture and due to the wounding of explants, ethylene accumulation can lead to abnormal biological responses, with potato seedlings being susceptible. Thus, investigating the effects of ethylene biosynthesis inhibitors such as pyrazinamide (PZA) and AgNO₃ on potato growth in vitro is essential.
Material and Methods: In this study, potato seedlings were cultivated in Murashige and Skoog (MS) medium, with concentrations of PZA ranging from 0 to 6 mg L⁻¹ and AgNO₃ at 2 mg L⁻¹. After four weeks, the seedlings were harvested and stored at -70°C for later analysis. The growth parameters measured included fresh weight (FW), dry weight (DW), stem and root lengths, leaf area, and leaf and root number. In addition, biochemical parameters, such as photosynthetic pigment levels, total phenol content (TPC), total reactive oxygen species (ROS), and proline concentration were analyzed. Statistical evaluations were conducted using SPSS and PAST software
Results: The results showed that the 2 mg L⁻¹ PZA treatment led to the highest FW and DW and increased leaf numbers; however, it was also correlated with a lower number of rooted plants. Conversely, treatments with 6 mg L⁻¹ PZA promoted longer stem growth, whereas control plants exhibited the largest leaf area, and AgNO₃-treated plants produced the longest roots. The accumulation of H₂O₂ in plants treated with ethylene inhibitors was like controls, but total ROS levels soared by 36% in those treated with 6 mg L⁻¹ PZA compared to controls. This suggests a link between reduced ethylene production, oxidative stress mitigation, and enhanced potato growth. Additionally, total ROS was positively correlated with stem length, but negatively correlated with root length.
Plants use several strategies to combat the damaging effects of ROS, such as the production of antioxidant compounds such as phenolics. Although PZA did not significantly alter TPC compared to controls, treatment with AgNO₃ caused a 61% reduction in TPC. Therefore, PZA did not appear to significantly affect phenolics production in the potato seedlings.
Proline, another critical antioxidant in plants, was found to accumulate significantly in the leaves of plants treated with 6 mg L⁻¹ PZA, which was more than 2.3 times higher than that in controls. This accumulation correlated positively with ROS levels at higher PZA concentrations but showed an inverse relationship with photosynthetic pigment levels.
The PCA revealed the relationships between the measured parameters and the applied elicitors. The samples were categorized into four distinct groups:

Control group: This group primarily exhibited higher FW, DW, and longer roots compared to the treated plants.
Low PZA dose group: These plants displayed elevated levels of photosynthetic pigments, TPC, and leaf area.
Medium PZA dose group: Correlations were observed with an increased number of roots.
6 mg L⁻¹ PZA and AgNO₃ group: These samples contained elevated levels of total ROS and proline.

Conclusion: The study concludes that low concentrations of PZA can stimulate growth while inhibiting ethylene production, resulting in fewer growth abnormalities compared to control plants. However, at elevated PZA concentrations, increased ROS levels may lead to oxidative stress, emphasizing the delicate balance in ethylene's role in plant growth and the necessity for further research to optimize conditions for potato cultivation in vitro. The findings contribute to a deeper understanding of how ethylene inhibitors can enhance potato propagation and possibly other crops in controlled agricultural environments.

Abstract Aim: Salinity stress is one of the most important environmental stress in the world and one of the important factors in reducing growth in many plants, especially in arid regions of the world. Salinity stress and increased sodium ion lead to the induction of oxidative stress and consequent cell death. Melatonin is a multiple function molecule spread in different plant and triggers several physiologic responses to different environmental stress. Exogenous application of melatonin to several plants can improve crop growth and development in response to many abiotic and biotic stresses with adjusting the antioxidant system of plants. Current studies reported that, the exogenous melatonin can increase plants' stress resistance by regulating both the enzymatic and non-enzymatic antioxidant defense process. In this study, the effect of melatonin on alfalfa roots under tissue culture condition was investigated. The aim of the present study was to investigate how melatonin regulated the antioxidant system and non-enzymatic antioxidants such as reduced glutathione and ascorbate under salt stress
Materials and methods: In this study, alfalfa seeds (Medicago sativa) of the Isfahani variety were used and we studied the effect of melatonin and salinity stress on the alfalfa root. In order to sterilize the seeds, they were placed in a 70% ethanol solution for one minute and then in a 20%  sodium hypochlorite solution for 20 minutes. After disinfecting the seeds, seeds were placed in each culture dish containing MS (Murashige and Skoog) culture medium. After germination, alfalfa seeds were transferred to MS culture medium containing concentrations of 0, 0.1, 10, and 15 micromolar melatonin and concentrations of 0, 150 and 200 mM salt. After 10 days of growth, total antioxidant capacity,
the activity level of catalase, ascorbate peroxidase, superoxide dismutase, guaiacol peroxidase, and glutathione reductase, ascorbate and glutathione levels in alfalfa roots were measured.
 
Results: Also, in the salinity stress, melatonin treatment significantly increased the total antioxidant power, while no significant difference was observed between different concentrations of melatonin, 0.1µM melatonin 82 درصد  and 62 درصد  raised antioxidant activity under 150 and 200 mM NaCl, so melatonin can reduce the levels of reactive oxygen species by scavenging of them through antioxidant enzyme or non- antioxidant system. Based on the results Melatonin treatment caused a significant increase in antioxidant power, the activity of CAT, APX, POD, SOD, GR enzymes, and antioxidant compounds in the glutathione-ascorbate cycle including DHA, ASC/DHA, GSH, and GSH/GSSG. along with increasing salinity concentration. On the other hand, salt stress increased oxidized compounds including DHA and GSSG in alfalfa roots. The data were carried out by two-way analysis of variance (ANOVA), followed by Duncan’s multiple range tests.




Conclusion: In addition to its direct role in clearing free radicals, melatonin activates the antioxidant defense system of the root, i.e. both antioxidant enzymes and antioxidant compounds in the ascorbate-glutathione cycle, which increases the resistance to damage oxidative effects caused by salinity stress in alfalfa root. These findings proposed that exogenous melatonin utilization dramatically activated ROS scavenging systems including enzymatic and non-enzymatic antioxidants to keep a relatively low amount of ROS and increased the tolerance of alfalfa root against salinity stress.