فصلنامه فرآیند و کارکرد گیاهی
سال سیزدهم شماره 6 (پیاپی 65، Feb and Mar 2025)

In this study, one product derived from sodium nitroprusside (SNP) was used as a nitric oxide (NO) donor and evaluated as a stimulant bud break agent of Ahmad-Aghaei pistachio. Trees were treated by SNP 0, 0.30, 0.60, 0.90 and 1.20 mM in two stages (4 and 8 weeks before normal budbreak (February 1 and January 1, respectively)) with a factorial experiment in a randomized complete block design with four replications. Results showed that SNP treatment hastened the bud break date and increased the yield. SNP decreased the misshapen nuts and empty and non-splitting shells compared with the control treatment. In both ON and OFF years, the effect of SNP was greatly dependent on both times of application and concentrations used. Results showed that exogenous application of this compound, especially during the second application, increased splitting shell nut, number of nuts per cluster, number of nuts per ounce, leaf area, shoot length, and shoot diameterin both ON and OFF years. No limitations were encountered. The results of this study might apply to pistachio and temperate fruit-growing regions with a mild winter. Because in mild winter, pistachio trees' chilling requirements are not resolved, and this substance helps with this deficiency.

Salinity stress is one of the most important environmental stresses limiting plant growth and performance. Salicornia persica is a species of Chenopodiaceae family; it is a halophyte and resistant to salinity. In addition, salicylic acid is known as an important molecule for the adaptation of plant responses to environmental stress. In the present study, the effect of salinity and salicylic acid on some morphophysiological traits of plants treated with three sodium chloride concentrations (zero, 200, and 500 ppm) and two salicylic acid concentrations (zero and 0.1 mM) and three harvest durations (1, 7, and 14 days) was investigated. This experiment was conducted as a factorial experimental design in the form of a completely randomized experimental design with three replicates. The initial results of the petridish trials showed that during salinity stress with increase in shoot length and decrease in the malondialdehyde levels compared to the control, the 0.1 mM salicylic acid treatment was more effective than other concentrations. The potting results showed that salinity stress caused a significant decrease in shoot and root dry weight. In addition, salt stress let to an increase in the amount of flavonoids and soluble sugars in most crops. The effect of salinity stress on the amount of pigments showed no particular trend. The amount of potassium increased at a salinity of 200 ppm and decreased at 500 ppm. The use of 0.1 mM salicylic acid increased the dry weight of the roots in all harvests. In addition, the use of salicylic acid increased the amount of chlorophyll b at salinity levels of 200 and 500 ppm. Also, the application of salicylic acid let to an increase in the amount of flavonoids at a salinity of 500 ppm, while the amount decreased at a salinity of 200 ppm. The application of 0.1 mM salicylic acid increased the content of potassium and soluble sugars in most harvests at 200 and 500 salinity levels. In general, the modulating effect of 0.1 mM salicylic acid on salinity stress was observed in Salicornia persica in most cases.

A research study was conducted at the Agricultural and Natural Resources Research Station in Miandoab to assess the impact of growth promoters on the quality of maize cultivar 370. The study followed a factorial experiment design with two factors and was organized as randomized complete blocks in three replications. The first factor examined bacterial strains of Azotobacter, including three levels: non-inoculated (control), Azotobacter sp. strain 5, and A. chroococcum DSM 1691. The second factor involved the bacterium Pseudomonas, with four levels: non-inoculated (control), Pseudomonas fluorescens 93—strain R 168, P. fluorescens DSM 50090, and P. putida DSM. The study evaluated various traits such as oil percentage, protein percentage, nitrogen percentage, forage digestibility percentage, ash percentage, insoluble fiber percentage, and fodder raw energy. The highest nitrogen percentages were achieved by inoculating maize seeds with A. chroococcum DSM 1691 and P. putida DSM, yielding values of 4.96% and 4.91%, respectively. Conversely, the control plants exhibited the lowest nitrogen percentage. Furthermore, the quantities of seed protein and forage digestibility percentage exhibited a significant increase following the inoculation of Rhizobacteria. The statistical data analysis revealed that the combined inoculation of bacteria A. chroococcum DSM 1691 and P. putida DSM enhanced the quality characteristics of maize, notably increasing the protein percentage (8.9%) and forage digestibility percentage (69.04%). Taken together, the application of growth-promoting Rhizobacteria resulted in an enhancement of indicators associated with the nutritional value of maize, exemplifying a sustainable agricultural strategy.

Salinity is one of the most important and widespread abiotic stresses that limit the growth of crops and productivity. To evaluate the yield and salt tolerance indices in contrast rice genotypes, a factorial experiment was conducted based on a randomized complete block design with three replications in 2022. The treatments included three levels of salinity stress (control, 4 and 8 dS.m-1) and 17 genotypes, including two sensitive and two tolerant check cultivars and 13 advanced (M10) mutant lines. Also, the investigated traits in this study were stress tolerance index (STI), stress susceptibility index (SSI), tolerance index (TOL), geometric mean productivity (GMP), mean productivity index (MP), and harmonic mean (HM) along with rice paddy yield (PY) in both normal and salt stress conditions. The results showed that salinity stress at both levels of 4 and 8 dS.m-1 markedly reduced PY in all the studied genotypes. The lowest values of STI (0.04) and TOL (-11.79) were recorded in IR29 and Deilamani cultivars, respectively. When the cultivars were grown at 4 dS.m-1 of salt stress, the MP10 genotype was superior in terms of GMP (1.32), MP (16.83), and HM (16.05) indices. By comparison, at salinity stress of 8 dS.m-1 the highest values for GMP, MP and HM indices were obtained in the MP10, MP6 and MP10 genotypes with 1.21, 8.32 and 5.42, respectively. Cluster analysis at salinity levels of 4 and 8 dS.m-1 showed that the studied mutants have a significant variation in stress tolerance indices. The MP10 mutant line achieved the highest PY, which was close to the Deilamani tolerant check cultivar when grown at under 8 dS.m-1 of salinity stress. Also, this promising line recorded the highest value of tolerance indices in both salinity levels of 4 and 8 dS.m-1. Therefore, the advanced mutant line of MP10 could be recommended for further research on salinity stress tolerance mechanisms.

Artemisia absinthium (L.) is known as wormwood and grand wormwood. The use of growth-promoting bacteria reduces environmental stress and improves plant growth. Some Bacillus spp. found in the rhizosphere of plants, which can produce auxin hormone and have phosphate dissolution ability, which improves plant growth. This study aimed to isolate Bacillus spp. from the rhizosphere of A. absinthium L. and to evaluate the ability of the isolated strains for auxin production and phosphate dissolution as well as their effect on biochemical indices of A. absinthium L. under salinity stress. Soil samples were collected from the rhizosphere of A. absinthium L. and Bacillus spp. were isolated and purified from them, utilizing an initial heat shock for bacterial spore selection and then cultivation of spores on nutrient agar. In the next step, quantitative measurements of auxin production capacity and inorganic phosphate dissolution were performed on the purified isolates, and then the selected isolates that had more auxin production and phosphate dissolution were biochemically and molecularly identified. Finally, the effect of selected bacteria on some biochemical characteristics of the A. absinthium plant under salt stress was investigated. The effect of four levels of inoculation (no inoculation, inoculation with B. cereus B strain, B. cereus E strain, and co-inoculation with B. cereus B strain and B. cereus E strain) was investigated on the biochemical indices of A. absinthium under three levels of salinity stress (control, 75 mM, and 150 mM). The production of malondialdehyde (MDA), protein, proline, superoxide dismutase enzyme (SOD), catalase (CAT), peroxidase (POX), and total phenol increased with increasing salinity. The results showed that the inoculation of Bacillus bacteria under salinity stress decreased proline and MDA and increased the amount of protein, total phenol and antioxidant enzymes (superoxide dismutase, catalase, and peroxidase). The best results were obtained by the combined inoculation of rhizosphere bacteria, B. cereus B and E strains, under salinity stress (75 mM NaCl), in which the greatest decrease in proline (90%) and MDA (90%) as well as the greatest increase in protein (9%), total phenol (180%), and antioxidant enzymes including superoxide dismutase (SOD) (50%), catalase (CAT) (40%), and peroxidase (POX) (70%) was obtained compared to the control.

Biostimulants are substances that promote plant growth and activate their metabolic pathways. This study investigated the effects of Gamma-aminobutyric acid (GABA) (5 and 10 mM), melatonin (50 and 100 μM), and potassium phosphite (2 and 3 g/l) on the growth and photosynthetic processes of Citrus aurantium L. seedlings. The results showed that the application of 10 mM GABA led to a significant increase in the plant's relative water content and CO2 assimilation rate. The highest dry weight, stomatal conductance, and the lowest leaf vapor pressure deficit were achieved with the application of 3 g/l potassium phosphite. Additionally, the maximum photochemical quantum yield of photosystem Ⅱ was found to be significantly higher with 10 mM GABA and 100 μM melatonin compared to the control and some other treatments. Furthermore, the application of 5 mM GABA resulted in a 31% increase in the content of chlorophyll b. Although GABA application led to a decrease in transpiration efficiency, this reduction may be attributed to the plants' higher stomatal conductance. Notably, 10 mM GABA caused the highest increase in stomatal density, while 50 μM melatonin and 3 g/l of phosphite resulted in the highest stomatal area. The concentrations of malondialdehyde and hydrogen peroxide were reduced in 10 mM GABA, which may have contributed to higher antioxidative potential and improved physiological parameters and plant growth. This research suggests that GABA can enhance the photochemical quantum efficiency of photosystem Ⅱ, improve light absorption efficiency, and modulate stomatal responses leading to enhanced photosynthetic efficiency in C. aurantium.

Chicory, blue-flowered perennial plant, Native to Europe, is cultivated extensively in the Netherlands, Belgium, France, and Germany and to some extent in North America. Its leaves are eaten as a vegetable or in a salad, and the roots may be boiled and eaten. The plant is grown as a fodder or herbage crop for cattle. Supplemental irrigation, an impressive strategy, diminishes the detrimental effects of drought on the productivity of rainfed plants. A factorial experiment was performed at Urmia University during 2016-2017. The experiment was included three factors; irrigation [without irrigation (rainfed) and supplemental irrigation], growing stage (vegetative and flowering) and fertilizers (control, mycorrhizal fungi (M, Funneliformis mosseae), Thiobacillus thiooxidans bacteria (T), M+T, vermicompost (V; 10 Mg ha-1), M+V, T+V and M+T+V). By supplemental irrigation, the amount of hydrogen peroxide, the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (G-POD) were significantly reduced. Dual inoculation of plants resulted in a significant decrease of electrolyte leakage and malondialdehyde (MDA). Also, in co-inoculation conditions, the amount of total phenolics content (TPC), soluble proteins, catalase, ascorbate peroxidase and guaiacol peroxidase activity were significantly increased, which this increment was more noticeable with vermicompost application. Biological yield was increased by 74.7%, in dually-inoculated and irrigated plants. The rate of root colonization in mycorrhized plants was significantly increased, which probably had a major role in the above results. Accordingly, combined use of mycorrhiza, Thiobacillus and vermicompost, as well as supplemental irrigation can improve the yield of chicory forage in rainfed condition.

The issue of heavy metal pollution poses a significant environmental concern, exerting detrimental effects on the growth and viability of plant life. Plants have evolved various mechanisms to effectively manage heavy metal stress, including the ability to modify their gene expression patterns. This adaptive response allows plants to mitigate the detrimental effects caused by excessive heavy metal accumulation. By altering their gene expression, plants can regulate the production of specific proteins and enzymes that aid in heavy metal detoxification and tolerance. Also, the changes that the plant makes in the production rate of secondary metabolites, including polyphenols, can be a mechanism to deal with the toxicity of environments contaminated with heavy metals. This sophisticated adaptation enables plants to maintain their physiological functions and overall health in the presence of heavy metal stress. This study utilized real-time reverse transcription polymerase chain reaction (RT-PCR) to examine and compare the differential gene expression of the plant, Tamarix hispida in addition to using HPLC to identify the amount of polyphenols in this plant. The plant was harvested from areas with varying levels of heavy metal pollution, including both non-polluted and polluted environments. The findings of this study reveal a noteworthy increase in the all NAC studied genes in T. hispida, within the contaminated site when compared to the uncontaminated area. Also, the consistent and inconsistent changes in the amount of polyphenols in this plant show that some polyphenols such as tamarixtein, hesperidin, galic acid and protocatechuica acid increased and some decreased such as quercetin, rutin, carsnoic acid, naringin acid and apigenine in the polluted environment. These results suggest that these genes and expression of secondary metabolites may play a crucial role in the process of metal detoxification, which allows the plant to tolerate heavy metals. The findings of our study offer valuable insights into the intricate molecular mechanisms underlying the resistance of T. hispida plant to heavy metals. Additionally, we identify promising candidates that could be utilized in genetic engineering approaches for phytoremediation purposes.

Utilizing complementary light spectra represents a potential novel approach for examining the enhancement of plant resilience amidst stressful conditions. The objective of this study was to explore the impact of various complementary light spectra on the growth and development of marigold plants under salinity-induced stress. The plants were cultivated in a greenhouse and exposed to blue, red, blue/red (2:1), blue/red (1:2), and white/yellow illumination throughout their growth stages. Stress conditions comprised control (non-stress) and salinity treatments (30, 60, and 90 mM NaCl). Salinity stress led to a reduction in fresh and dry weights, as well as leaf area index, while increasing proline content and Na concentration in roots and shoots. The combination of blue and red spectra caused superior stress mitigation compared to other spectra. Salinity stress reduced leaf chlorophyll and RWC, however, blue/red (2:1) treatment enhanced both parameters under NaCl stress. Salinity also increased the amount of total phenol content. White/yellow light exerted the most pronounced effect in reducing total phenol content at 90 mM salinity. Sodium uptake increased under stress, while potassium uptake decreased. The sentence was corrected. It can be concluded that the effects of salinity stress can be reduced by manipulating the supplemental light spectrum. The use of artificial light can be extended to stress.

Mercury is one of the toxic and heavy metals that causes pollution in agricultural fields. Mercury aggregation disturbs cellular behaviors and stops plant growth. In order to examine the effects of mercury on wheat growth indexes, a study with 4 commercial genotypes of Iran, Sirvan, Sivand, Parsi and Sepahan in various levels of this element (0, 30, 70, 100 mg/kg soil) was conducted. This experiment has been conducted in a random factorial design with 3 replications and indices including CO2 assimilation rate (A), transpiration rate (E), stomatal conductance (gs), water use efficiency (WUE), PSII photochemical efficiency (FV/FM), photosynthesis quantum yield (Y), electron transfer rate (ETR), intra-leaf CO2 concentration (Ci), chlorophyll a, chlorophyll b, total chlorophyll, chlorophyll a/b, chlorophyll stability index and carotenoids were measured after 60 days. The result indicated that all measured parameters except carotenoid were decreased as mercury concentration increased. In 100 mg/kg stress level, Sirvan genotype had the highest transpiration rate, chlorophyll a, b, total chlorophyll, carotenoid, PSII efficiency and Ci as compared to other investigated genotypes. Also, Sepahan genotype showed the highest increase in chlorophyll stability index, stomatal conductance, ETR and quantum yield of photosynthesis at a stress level of 100 mg/kg as compared with control plants. Parsi genotype had the lowest transpiration rate, stomatal conductance, PSII efficiency, ETR and Ci at a stress level of 100 mg/kg as compared to other investigated genotypes. Based on these results, Parsi genotypes can be introduced as sensitive genotypes, and Sivand and Sirvan genotypes can be introduced as tolerant genotypes to mercury treatment.