فصلنامه فرآیند و کارکرد گیاهی
سال چهاردهم شماره 1 (پیاپی 66، فروردین و اردیبهشت 1404)

The experiment was conducted in two consecutive years (2015 and 2016) at the Faculty of Agriculture of Guilan University, Rasht, Iran. Cultivation was done in polyethylene pipes in both years. In the first year, the experiment was conducted with 16 (aerobic, upland and lowland) rice genotypes under optimal irrigation conditions, using a completely randomized design with three replicates. Based on cluster analysis results four cultivars Vandana, Neda, Tarom Mahalli, and one upland (IR83141-11) genotype were selected for the second year experiment. The second-year experiment was a factorial design conducted with complete randomization and three replications. The factors were included four rice genotypes and soil water conditions (full irrigation and drought stress). The results indicated that drought stress reduced both the dry matter and growth rates of shoots and roots in rice cultivars. The difference in shoot dry matter between the two irrigation conditions was greater in the Tarom Mahalli (16.2 g.plant-1) compared to the upland genotype (6.7 g.plant-1) and other genotypes. The shoot was more affected by drought stress than the root. The difference in root dry matter between the two irrigation conditions was greater in the Tarom mahalli (1 g.plant-1) and upland genotype (0.09 g.plant-1) and other genotypes. The root dry matter variation between the two irrigation conditions was greatest in the Tarom Mahalli (1 g.plant-1) and lowest in the upland (0.09 g.plant-1). Drought conditions led to a shorter timeframe for the Vandana cultivar to reach maximum growth rate and achieve maximum dry matter accumulation, with growth rate accelerating by three days and accumulation occurring six days earlier. Due to drought stress, the time to reach maximum root dry matter decreased in Neda and Vandana cultivars (with a difference of 4.65 and 0.13 days) and increased in upland genotype and Tarom Mahalli cultivar (2.5 and 6.5 days). Drought stress caused a five-day acceleration and a seven-day delay in reaching the maximum accumulation of root dry matter in Neda and Tarom Mahalli cultivars, respectively. Aerobic and upland genotypes displayed a greater root-to-shoot ratio compared to lowland genotypes, particularly during the initial growth stages, suggesting a more extensive root system in these genotypes. Except for the Tarom Mahalli, drought stress increased root dry weight in other genotypes at most soil depths compared to full irrigation. These traits play a crucial role in breeding programs, particularly those focused on drought tolerance, in order to develop resilient cultivars that can withstand challenging conditions. In this experiment, it is suggested that further research could be conducted on the Vandana, upland, and Neda genotypes due to their superior root traits.

Rapeseed is a valuable oil plant belonging to the Brassicaceae plant family, and considering that today soil salinity is one of the most important limiting issues in agriculture. Therefore, investigating the effect of salicylic acid (as a biological stimulant and agent to improve the antioxidant defense system) on plants under salinity stress conditions in order to reduce the negative effects of salinity stress seems necessary. In this research, the mutual effects of NaCl and salicylic acid on the antioxidant defense system and the distribution of some elements in rapeseed plants of Hyola variety were investigated. For this purpose, 21-day-old seedlings were subjected to concentrations of 0, 50, and 100 mM NaCl and SA with concentrations of 0 and 500 μM SA for 2 weeks. The obtained results showed that the activity of the antioxidant enzymes superoxide dismutase and catalase, as well as the amount of H2O2 in saline treatments in the presence of SA were lower than their values in saline treatments without the presence of SA, which shows a reduction in the level of tension in the presence of SA. Because the decrease in the activity of antioxidant enzymes indicates the decrease in the level of stress and the decrease in the amount of hydrogen peroxide is an indicator of the reduction of membrane damage in stress conditions. Also, an increase in root sodium concentration in salinity treatments was seen in the presence of SA, which could be due to the accumulation of sodium Na in the root and its lack of transfer to the aerial parts, which is a way to deal with stress, and an increase in potassium concentration in roots in saline treatments. , was observed in the presence of SA and since potassium plays an important role in regulating the osmotic potential of cells, this increase can indicate the positive effect of SA in reducing the destructive effects of salt stress. In general, the data show that the presence of SA has increased the resistance of this canola cultivar to salinity, also, the results prove that the application of SA at a concentration of 500 μM can limit the negative effects of salinity on the rapeseed Hyola plant.

Strawberry is a very tasty fruit with high nutritional value, so it is important to increase the size of the fruit and its quality. The aim of this study was to investigate the effect of boron and vitamin C on the yield and quality of strawberry fruit. The research was carried out as a completely randomized design experiment with 9 treatments and 4 replications at the beginning of flowering. The treatments include boron (50 and 100 mg/L) and vitamin C (150 and 300 mg/L) and their combination. Traits such as leaf area, chlorophyll index, weight of primary fruit, weight of secondary fruit, number of achenes of primary fruit, number of hazelnuts of secondary fruit, yield, soluble solids, pH, organic acids and vitamin C were investigated. The results showed that the use of different concentrations of boron and vitamin C and the combination of these two causes the improvement of leaf surface, chlorophyll index, primary fruit weight, secondary fruit weight, primary fruit hazelnut number, secondary fruit hazelnut number, yield, soluble solids, pH, organic acids and vitamin C of strawberry fruit. Combination treatments of 100 mg/L of boron and 300 mg/L of vitamin C and combination treatment of 100 mg/L of boron and 150 mg/L of vitamin C, combination of 50 mg/L of boron and 300 mg/L of vitamin C, and combination treatment of 50 mg/L of boron and 150 mg/L of vitamin C showed better results in the examined traits. According to the results obtained from the present research, the combination of boron and vitamin C improved the quantitative and qualitative characteristics of strawberry fruit better than their use alone.

The anti-diabetic medicinal plant of Chamaecostus cuspidatus Nak is an important medicinal plant due to having an extensive range of bioactivities, including anti-diabetes, anti-cancer and anti-inflammatory. This research investigates the effects of different concentrations of growth regulators, namely NAA and BA, on nodal explants in two separate experiments on plant micropropagation. This experiment was conducted using a factorial in a completely randomized design (CRD). The Hormonal concentrations in the first experiment include treatments of BA (0, 2, 4 and 6 mg/L-1) with NAA (0, 0.3 and 0.6 mg/L). The results of the first experiment led to the design of the second experiment with optimal concentrations. The second experiment included BA (0, 1, 2 mg/L-1) with NAA (0, 1.2, 2.4 mg/L-1) in MS culture medium. The results of the first experiment showed that the highest Percentage of shoot induction, number of leaves, plant height, shoot fresh weight, Percentage of root induction, root fresh weight, root diameter and photosynthetic pigments among different treatments related to zero BA treatment with 0.6 mg/L NAA and The lowest value corresponds to the control. The results of the second experiment showed that the culture medium containing 2.4 mg/L of NAA along with 1 mg/L of BA had the greatest effect on seedling growth and shoot growth. The highest root length (20.33 cm) was obtained in the medium under treatment with 1.2 mg/L of NAA with zero and 1 mg/L BA and 2.4 mg/L of NAA with 1 and 2 mg/L BA. Additionally, the index of chlorophylls showed a direct relationship with the growth of aerial organs and proper propagation, so that the amount of chlorophylls increased with the growth of the plant (1 mg/L BA with 2.4 mg/L NAA). The present study demonstrated that the plant requires a small amount of the hormone BA (1 mg/L) for enhanced shoot growth. On the other hand, increasing the amount of NAA from 1.2 mg/L to 2.4 mg/L did not show a significant difference in root growth, and at a concentration of 2.4 mg/L, the plant exhibited callus formation.

Aromatic geranium is an ornamental plant whose essential oil is widely used in perfumery, health and cosmetic, food and pharmaceutical industries. In order to investigate the reduction of the adverse effects of low water stress in Aromatic Geranium (Pelargonium graveolens) plants by proline and glutamine foliar application, a factorial experiment was conducted based on a completely randomized design with 3 replications in a commercial greenhouse located in Garmsar city in 1402-1403. The experiment was done in pots with 3 levels of low water stress (30, 70 and 100% of field capacity) and spraying with proline and glutamine (each with two levels of 50 and 100 mg/liter) and their interaction. Low water stress was applied after the plant’s establishment and in the 6 to 8 leaf stage. Foliar spraying with proline and glutamine at different levels was done in two stages. Finally, sampling and evaluation of traits was done about two weeks after the last spraying. The results showed that the highest fresh and dry weight of shoots (71.42 and 9.12 g), petals anthocyanin and total leaf chlorophyll (3.2761 and 16.4217 mg/g FW) and the lowest ionic leakage of the cell membrane (54.27%) were in glutamine 100 mg/L at 100% FC treatment. The highest root fresh and dry weight (16.35 and 3.67 g), the longest root length (45.28 cm), catalase, superoxide dismutase and peroxidase enzyme activity (8.23, 3.28 and 17.42 U E/g FW) and lowest proline amount was obtained in proline 100 mg/liter at 100% FC treatment. The longest shelf life of aromatic geranium flower on plant was (14 days) in glutamine 100 mg/liter at 100% FC treatment and the lowest (8 days) in control treatment at 30% FC. In total, proline and glutamine with regulating osmotic pressure, inhibiting oxygen free radicals, and preventing membrane proteins and phospholipid degradation, caused a reduction low water stress negative effects in foliar-sprayed plants compared to the control in 70 and 30% FC. Therefore, it is possible to recommend proline and glutamine foliar application under low water stress conditions to improve aromatic geranium (Pelargonium graveolens) growth, quality and flowering.

In order to evaluate the effects of stress modulators (vermicompost, arbuscular mycorrhiza fungi and foliar application of putresin and nano zinc oxide) on fluorescence chlorophyll components and some physiological traits of barley under salinity stress conditions, an experimental as factorial was conducted based on randomized complete block design with three replications at the research greenhouse, faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabil in 2022. The experimental treatments were included salinity in three levels (no salinity as control, salinity of 40 and 80 mM) by NaCl, bio fertilizers in four levels (no application as control, application of vermicompost 50 g/kg of soil, arbuscular mycorrhiza fungi 20 g/m2 of soil, both application of vermicompost and mycorrhiza), foliar application of putrescine and nano zinc oxide in four levels (foliar application with water as control, foliar application 0.4 g.L-1 nano zinc oxide, 0.8 mM putrescine, foliar application of nano zinc oxide and putrescine). The results showed that in stages of flag leaf emergence and heading under the highest salinity level, simultaneous treatment of stress modulators (vermicompost, arbuscular mycorrhizal fungi, putrescine and zinc oxide) increased chlorophyll index (34.8 and 29.5% respectively), nitrogen index (28 and 21.6% respectively), stomatal conductivity (58.94 and 77.9% respectively), relative water content (45.4 and 46.1% respectively), quantum yield (16.3 and 110% respectively), maximum fluorescence (38.6 and 41.48% respectively), variable fluorescence (61.2 and 196.3% respectively) in comparison with no application of stress modulators at the same level from salinity levels. Also, at the highest salinity level, simultaneous treatment of stress modulators increased 34.2% grain yield in comparison with no application of stress modulators at the same level from salinity levels. Based on the results of this study, simultaneous treatment of stress modifiers (vermicompost, arbuscular mycorrhizal fungi, and foliar spraying of putresin and nanooxydroi) was able to compensate a part of the reduction of barley yield under salinity conditions due to improving fluorescence chlorophyll components and some physiological traits such as chlorophyll indices, quantum yield and stomatal conductivity.

Industrial developments and population growth all over the world have caused soil pollution and the increase of heavy metals in the soil, and it is necessary to provide solutions to reduce the absorption of heavy metals by plants. For this purpose, an experiment was conducted on spinach (Spinacia oleracea L.) in the research greenhouse of the Faculty of Agriculture and Natural Resources, Islamic Azad University, Karaj Branch, for 2 years (2018-2019) to determine the effect of biochar on soil and plants after two years. The experiment was conducted as a factorial in the form of a completely randomized design in three replications. The research treatments included biochar at two levels (0 and 5% volume/volume) and cadmium at four levels (0, 10, 20, 30 mg/l). The results showed that the highest dry weight of shoot (3.54 g/plant) was observed in the mutual effects of biochar and no cadmium use. Plant yield decreased in treatments with cadmium, and in general, biochar increased spinach yield compared to the control, and as a soil amendment, it was a good choice to increase spinach growth. Biochar reduced catalase enzyme activity by 62.5%, ascorbate peroxidase enzyme activity by 32.60% and superoxide dismutase enzyme activity by 58.86% compared to the control. Also, 30 mg/l cadmium treatment increased catalase enzyme activity by 87.5%, ascorbate peroxidase enzyme activity by 41.07%, and superoxide dismutase enzyme activity by 87.46% compared to the control. Therefore, the use of biochar in reducing the effects of cadmium stress is recommended.

Thymus vulgaris L. is an aromatic plant belonging to the Lamiaceae family, known for its valuable medicinal and nutritional properties. Drought stress, as one of the most significant abiotic stresses, can have adverse effects on the growth and performance of medicinal plants. To investigate the effect of drought stress on some morphological, physiological, and biochemical traits of thyme, an experiment was conducted in a completely randomized design with four levels of drought stress (100%, 75%, 50%, and 25% of field capacity) with three replications in 2021 in the greenhouse of Hormozgan University. The results showed that drought stress (25% of field capacity) significantly reduced leaf length (64%), leaf width (33%), plant height (51.13%), root length (49.4%), fresh weight of aerial parts (4.04%) and dry weight of aerial parts (7.5%), dry weight of roots (9.7%), relative water content (54.23%), chlorophyll a (31.45%), chlorophyll b (31.29%), total chlorophyll (31.38%), and carotenoids (22.35%). The highest levels of electrolyte leakage (34.56%), proline (53.12%), catalase (68.47%), polyphenol oxidase (51.52%), malondialdehyde (55.84%), flavonoids (59.23%), and anthocyanins (61.29%) were observed in the 25% field capacity drought stress treatment. The medicinal plant thyme responds to drought stress by employing various defense mechanisms. These mechanisms include reducing certain morphological characteristics to conserve energy, rapidly accumulating osmotic regulatory organic compounds to maintain cellular water balance, and increasing antioxidant enzyme activities to combat oxidative stress. Through these responses, thyme can continue to grow and absorb the necessary nutrients with higher efficiency. The primary objective of this research was to evaluate the drought tolerance of thyme and determine the most suitable conditions (75% and 50% of field capacity) for cultivating this plant in Hormozgan Province. Given that thyme is not widely cultivated in this region, examining the plant's response to drought stress could provide valuable information for expanding its cultivation in similar areas.

In this research, the effect of foliar application of gamma-amino-butyric acid (GABA; 0, 1.5 and 3 mM) on abscisic acid, soluble sugars, polyamines, the activity of some antioxidant enzymes, and membrane stability index of two grape cultivars (Khalili and Perlette) was investigated under greenhouse condition with two temperature treatments (2ºC and 24ºC) factorially (2×3) based on a completely randomized design with three replications. The vines were sprayed with different concentrations of GABA at the 15-leaf stage. After 24 hours, half of the vines treated with GABA along with the control plants were exposed to 2ºC (cold stress condition) for 12 hours and the rest vines (treated with GABA and control) were kept at 24ºC (non-stress condition) and sampled after 12 hours. The application of GABA under cold stress conditions caused a preservation of chlorophyll and a decrease of ion leakage, malondialdehyde and hydrogen peroxide and increase of protein, proline and abscisic acid content compared to control plants in both cultivars. The amount of sucrose, fructose and glucose in the leaves was higher in the treated Khalili cultivar compared to the Perlette cultivar under cold stress. Also, under cold stress, GABA spray led to an increase in the amount of polyamines of putrescin, spermine and spermidine. Under cold stress, the activities of superoxide dismutase and catalase enzymes at a concentration of 3 mM and ascorbate-peroxidase at a concentration of 1.5 mM of GABA showed the highest value compared to the control plants. GABA treatment maintained membrane stability and increased cold tolerance of vines by increasing in abscisic acid content, soluble sugars and antioxidant system, The effect of GABA on the cold tolerance of Khalili cultivar was greater than that of Perlette cultivar.

Considering the role of salicylic acid and methyl jasmonate in regulating important metabolic processes and their potential in increasing the production of important biological compounds, the effect of the use of these two hormones was investigated on various traits of common yarrow. The seed-derived transplants were grown under greenhouse conditions in a factorial experiment in a completely randomized design with three replications. Salicylic acid with a concentration of 1 and 2 mM and methyl jasmonate with a concentration of 0.5 and 1 mM were sprayed on the leaves separately and in combination three times with an interval of 15 days. The content of phenols, flavonoids, antioxidant capacity, photosynthetic pigments, the expression of key genes involved in the biosynthesis of phenyl-propanoids, including phenylalanine ammonialyase (PAL) and chalcone synthase (CHS) genes, and also essential oil yield were compared in the treated and control plants. Variance analysis showed the significant effect of two hormones on the examined traits. Except for the negative effect of methyl jasmonate on biomass (dry weight and height) and chlorophyll, and also the negative effect of salicylic acid on carotenoids, the impact of these two hormones was positive on other traits. Interestingly, in the combined treatment, the synergistic effect of methyl jasmonate and salicylic acid was observed on most traits in yarrow plants. The effect of the combined treatment of salicylic acid and methyl jasmonate was somewhat different in the studied traits, however, the highest yield of essential oil and the expression of PAL and CHS genes were obtained in the treatment of 1 mM methyl jasmonate and 2 mM salicylic acid. In general, the effect of methyl jasmonate and salicylic acid on yarrow was dependent on the trait type. Considering the performance of the essential oil, the content of phenols and flavonoids, and the expression of PAL and CHS genes, the treatment of 1 mM methyl jasmonate and 2 mM salicylic acid is recommended to enhance the growth of yarrow.

European pear (Pyrus communis L.) belonged to Rosaceae family and Maleae subfamily. To expand our knowledge about this species, the developmental stages of anthers and pollen grains of the Bartlett cultivar were investigated with common histological methods such as fixation in FAA, dehydration, embedding in paraffin, sectioning with a microtome, and hematoxylin-eosin staining. The findings showed that the anthers are bitheca and tetrasporangiate. The developmental pattern of the anther wall follows the basic type. Cytokinesis of microspores is simultaneous, and the arrangement of microspores is tetrahedral. The tapetum is of glandular type with a single layer, and the tapetal cells are binucleate. Mature pollen grains are two-celled, tricolpate, and exine sculpturing is striate. The anthesis of the anther is introse and takes place through longitudinal slits, and the pollen grains are released as monad. To investigate the effect of temperature on the germination of pollen grains, three cultivars Bartlett, Natanzi and Dargazi were used. An increase in temperature accelerates the germination rate of pollen grains in all three cultivars. At 5°C, the germination percentage was generally lower in all cultivars. In all three cultivars, pollen grain germination was zero at both 0 and 1 hour. As time passed, particularly at 2 and 4 hours, the percentage of germination increased significantly. However, after 4 hours, the germination rate in all three cultivars showed only a slight increase. Pollen grains at 5°C exhibited lower germination compared to other temperatures. These results indicate that 5°C is not a suitable temperature for pollen germination in these cultivars, while 25°C appears to be the optimal germination temperature for all cultivars.

Peach (Prunus persica L.) belongs to the Rosaceae family and is considered one of the most important fruits in temperate regions. Fruit quality is one of the important factors in the development and marketing of this product. The use of some chemicals and hormones play a significant role in increasing the shelf life and quality of fruits. To investigate the impact of putrescine application timing on maintaining the quality of fig peach fruit, this research was conducted in a factorial design using a randomized complete block design. Putrescine treatments were administered at two different times, each with three replications, on the fig peach variety. Chemical treatments were applied at three levels (0, 10, 15 mM) through foliar spraying 14 and 28 days before harvesting the fruits. Following the application of treatments, the fruits were harvested at the stage of commercial maturity, transported to the laboratory, and evaluated for various quality parameters, including total soluble solids, acidity, vitamin C, firmness of the fruit tissue, pH of the fruit extract, phenol, flavonoid, and total antioxidant levels during harvest. The average data indicated that increasing the concentration of putrescine up to 10 mM resulted in a higher titratable acidity compared to the control. However, with a further increase in putrescine up to 15 mM, the titratable acidity did not show a significant difference compared to the control. Moreover, increasing the concentration of putrescine 14 days before harvest led to an increase in the percentage of total soluble solids compared to the control. The highest amount of dissolved solids, following the control treatment, was observed with the 15 mM putrescine treatment 28 days before harvesting. The total antioxidant levels showed that none of the concentrations and timings used had a significant effect on this characteristic. At time B1, the amount of flavonoids increased with the rise in putrescine concentration, while at the time 28 days before harvest, the amount of flavonoids decreased with increasing putrescine concentration. The highest level of hardness was observed 14 days before harvest.

The main postharvest problems of persimmon are severe softening and disease incidence on the fruits during storage. Developing postharvest protocols, incorporating nonchemical compounds with the aim of extending persimmon fruit shelf life and maintaining quality, is one of the major issues regarding the persimmon fruit industry. Given the documented benefits of chlorogenic acid in maintaining fruit quality and extending shelf life, this study investigates its effects on the quality attributes and antioxidant properties of persimmons. This study was performed as a factorial experiment was conducted based on a completely randomized design with three replications. The first factor was chlorogenic acid concentrations of 0, 25, 50, and 100 µM treatments, and the second factor was storage time (15, 30 and 45 days), then treatments fuits were stored at 1 °C and 85-90% relative humidity for 45 days. Results indicated that concentrations of 50 and 100 µM chlorogenic acid yielded optimal outcomes in extending persimmon shelf life. Significant enhancements in firmness, total phenol content, total flavonoid content, soluble tannin, phenylalanine ammonia lyase (25 U/mgFW) and ascorbic acid (24.2 mg/100 gFW) were observed in fruits treated with 50 and 100 µM chlorogenic acid, chlorogenic acid 50 and 100 µM prevented the decrease of ascorbic acid (64.5%) compared to control. Moreover, treatment with 100 mM chlorogenic acid markedly increased total antioxidant capacity compared to the control. In conclusion, the application of chlorogenic acid 50 µM emerges as a recommended strategy for mitigating losses, preserving quality, and extending the shelf life of persimmon fruits during postharvest handling.

Unicellular green alga Dunaliella is very important in physiological studies due to its resistance to salinity stress and its lack of cell walls. Many microalgae are rich in sources of lipids and fatty acids, which can be used to produce biodiesel, which is less polluting than fossil fuel.  The effect of 10, 25, 50, 75, 100, and 120 micromolar ethanolamine concentrations was examined on the growth rate, chlorophyll, and beta-carotene content of two algae D. salina and D. bardawil, as well as the saturated and unsaturated fatty acids profile.  The results showed that low concentrations of ethanolamine did not affect the growth rate and chlorophyll content whereas high concentrations inhibited growth rate and chlorophyll synthesis. In general, both algae were not affected by ethanolamine, only lipid content in D. bardawil increased at 50 micromolar ethanolamine. It seems, that in high concentrations of ethanolamine treatment, the suberates, and the energy instead of being used in cell division and chlorophyll synthesis, probably deviated in response to high concentrations of ethanolamine or lipid synthesis.  In two applied ethanolamine concentrations (25 and 50 micromolar) and control during one-week experiments, D. salina had two times higher lipid content than D. bardawil. Moreover, D. bardawil showed higher beta-carotene content than D. salina. The lower beta-carotene and higher lipid content in D. salina and higher beta-carotene and lower lipid content in D. bardawil revealed the probable relationship between lipid production and beta-carotene content. Under the treatment of ethanolamine, no big changes in the saturated and unsaturated fatty acid profiles were observed in D. salina. An increase in heptadecanoic acid as a saturated fatty acid and oleic acid as unsaturated fatty acid in D. bardawil was detected.

Among the toxic heavy metals is cadmium, which is considered as a potential risk for humans and other organisms and requires more attention to prevent this metals to entering the food chain. In recent years, along with the development of nanotechnology, it has been used to advance environmental goals. In order to study the effect of zinc oxide- and titanium dioxide-nanoparticles on white grape (cv. Sultana) seedlings under Cd stress, a factorial experiment was conducted based a completely randomized design with three replicates. The first factor was cadmium stress at three levels (0, 50 and 100 mg/kg soil) and the second factor was the spraying of the nanoparticles of zinc oxide and titanium dioxide at 3 levels (0, 50 and 100 mg L-1). The results showed that cadmium stress significantly reduced the growth parameters and photosynthesis pigments, and increased H2O2 and malondialdehyde (MDA) contents and antioxidant enzymes activity of guaiacol peroxidase (GPX) and super oxide dismutase (SOD). Foliar application of zinc oxide- and titanium dioxide-nanoparticles improved morphological characteristics, photosynthetic pigments and enzymatic antioxidants but reduced MDA and H2O2 contents under cadmium stress. Based on the results of this research, it seems that foliar spraying the nanoparticles of zinc oxide and titanium dioxide (especially at the concentration of 100 mg L-1), can improves the growth, photosynthetic pigments and antioxidant enzymes activity under cadmium stress, and increases plant tolerance to harmful effect of this toxic metal in grape cv. Sultana.

This research was aimed at evaluating the effects of salicylic acid (SA) on seed germination and growth of quinoa (Chenopodium quinoa willd.) seedlings under cadmium (Cd) stress. Factorially in the form of a completely randomized design in four replications in the Seed Science and Technology Laboratory of Mohaghegh Ardabili University in the year 2022. The experimental treatments included SA at four levels (0, 1.5, 2.5, and 3.5 mM) and Cd at four levels (0, 200, 300, and 400 mg/liter). Characteristics of germination percentage (GP), average germination duration (AGD), germination speed (GS), average daily germination (ADG), coefficient of variation of germination time (CVT), index of uncertainty of germination process (UGP), index of germination simultaneity (IGS), time to 75% germination (TG), and Anti-Enzymatic oxidants were evaluated. The results showed that the interaction of two factors was significant on almost all traits, so that with the application of 400 mg/liter of Cd in the conditions without the application of SA, the percentage of germination was about 27.67%, the coefficient of variation of germination time was about 42 11.0%, germination speed was 13.7%, germination synchronicity index 17.64%, daily germination percentage 34.32%, seedling dry weight 35.48% and quinoa seedling length 59.76% compared to the control treatment decreased. Although cadmium stress reduced the characteristics of seed germination and the growth of quinoa seedlings, under cadmium stress, the application of a 2.5 mM concentration of salicylic acid increased the germination percentage by 13.17% and the germination rate by 52.28%, 6.81 to 73. 35.0% Z index, 99.33% dry weight, and 79.68 to 91.63% length of quinoa seedlings were observed. Also, 42.90% decrease in average germination time, 11.42% decrease in average germination time coefficient, and 6.28 to 38.93% U index were reported by treatment with 2.5 mM concentration of salicylic acid. . The use of salicylic acid at a concentration of 2.5 mM in different levels of cadmium stress reduces the negative effect of cadmium stress by increasing the strength of seeds and seedlings, increasing the activity of antioxidant enzymes, and improving the characteristics of germination and seedling growth.

In order to investigate the effect of priming on germination indicators and antioxidant enzyme activity in Marigold under salinity stress, a factorial experiment was conducted based on a completely randomized design with 3 replications. Treatments were accelerated at four salinity levels (0, 50, 100, and 150 mM) and four priming levels (control (distilled water), priming with salicylic acid (100 mg/L), gibberellin (20 mg/L) and chitosan (0.8% weight volume, all of which had been dissolved in 1% acetic acid). The results showed that the germination percentage (GP), seedling length (SL), Allometric Coefficient (CA) and Seedling weight vigor index (SWVI) decreased by 21, 37, 17 and 43% respectively compared to the salinity control, but priming with salicylic acid, gibberellin especially chitosan improved these traits. The lowest Daily Germination Speed (DGS) in priming with salicylic acid and gibberellin, especially priming with chitosan, and Mean Germination Time (MGT) were obtained in priming with chitosan and without salinity. The Germination rate (GR) and Seedling length vigor index (SLVI) in chitosan treatment and non-salinity compared to the control and 150 mM salinity showed an increase respectively about 75% and 73%. The catalase (CAT) and superoxide dismutase (SOD) enzymes activity in priming with chitosan compared to the control (distilled water) showed an increase respectively of about 18% and 15%. Also, peroxidase (POX) enzyme activity in priming with chitosan and salinity of 150 mM was about 32% higher than the control (distilled water) and salinity of 50 mM. The results showed that seed treatment with salicylic acid, gibberellin, especially chitosan by stimulating antioxidant enzymes and neutralizing free radicals can reduce the harmful effects of salinity stress on some traits in Marigold seedling and improve seedling growth. Therefore, since pot marigold seeds are generally weak and have low germination power, the application of 0.8% chitosan is a suitable option for improving germination and seedling growth of this plant.

The toxicity of the heavy metal nickel in plants causes oxidative stress and the production of energetic radicals (ROS) such as superoxide (O2-), hydrogen peroxide (H2O2) and hydroxyl (OH-). If the amount of ROS accumulation exceeds the ability of the antioxidant system, the cell will be damaged and the sensitive tomato plant will suffer a reduction in growth. The application of titanium nanoparticles increases the resistance to nickel stress by increasing the antioxidant power and improving plant growth. In this research, the comparative and reciprocal effect of 50 mg/liter of two types of green nanoparticles (GNP; using oregano plant extract) and synthetic (SNP) titanium dioxide with a size of 10 to 30 nm on improving the growth and resistance of tomato. Early Urbana cultivar was studied under the stress of 150 µM nickel-II sulfate in the greenhouse environment as a factorial experiment in the form of a completely randomized design. The results showed that the separate application of two green nanoparticles (GNP) and synthetic titanium (SNP) had a significant effect on the improvement of stem fresh weight (16.38 g/plant) and root length growth (30.04 cm), ion leakage (31 2.2%), MDA (0.084 nM), root potassium accumulation (1.69%) under nickel stress conditions. However, the cross-application of green nanoparticles with the synthetic type led to further improvement of measured traits such as stem magnesium nutrition (7.34%), stem iron (2.79%), stem nickel accumulation (0.028%), catalase enzyme activity (29. 8 enzyme U) and leaf surface (11.6 cm2) were treated with 150µM nickel toxicity and was able to reduce the toxic effects of nickel stress well. Therefore, in some other traits such as the improvement of stem H2O2 accumulation (4.6 µM), the separate application of green nanoparticles under nickel stress had a better effect than synthetic titanium nanoparticles. However, the application of green titanium nanoparticles individually or together increased the resistance of plants under nickel stress and is a proposed method compatible with the environment.

Melatonin is one of the growth hormones that can induce growth and primary and secondary metabolites in microalgae. Green microalgae, including Chlorella vulgaris can be considered renewable sources of biomass and secondary metabolites. This research was studied to investigate the effects of this hormone on the growth and biochemical parameters of Chlorella vulgaris microalgae. For this purpose, microalgae were cultured under concentrations of 0, 0.1, 1, 10, 100 and 500 µM melatonin. After 21 days, microalgae were used to measure parameters. The results showed that the maximum productivity of biomass, cell number, and chlorophyll pigments were observed under the concentration of 10 µM and the lowest value of these parameters was observed at the concentration of 500 µM melatonin. Also, the maximum amount astaxanthin and lutein pigments, phenolic compounds and antioxidant capacity were obtained under the concentration of 500 μM. According to the above data, it can be suggested that melatonin, by producing reactive oxygen species and its regulatory role, induces growth parameters and chlorophyll pigments in optimal concentrations, and on the other hand, by increasing PAL enzyme activity, the content of phenolic compounds and increases carotenoid pigments. The increase in these compounds ultimately leads to the improvement of the antioxidant capacity of microalgae.

Water stress and low percentage of soil nutrients in arid climates are considered limiting factors for the growth of agricultural products. Proportionate feeding of plants is useful in reducing the negative effects of drought stress. The experiment was factorial in the form of a completely randomized design with drought stress treatment (85, 70 and 55% FC) and treatments including glycine betaine and humic acid at 6 levels (no application, 2 mM glycine betaine, 4 mM glycine betaine, 4 kg/ha of humic acid, 6 kg/ha of humic acid and 2 mM glycine betaine + 4 kg/ha of humic acid) with 3 replications. According to the results, both drought and amino acid treatments played a role in increasing soluble carbohydrates. Thus, the highest amount of soluble carbohydrates was observed in the treatment of glycine betaine 2 + humic acid 4 and in the most severe drought stress (55%) at the rate of 1.21 mg/g. The increase in the severity of drought stress led to an increase in the amounts of vitamin C and pyruvic acid. In other words, onions with less water were spicier. Both amino acids in all the concentrations used had the effect of increasing vitamin C and pyruvic acid. With the increase in the level of stress, total phenol production also increased. So that in 55% FC, total phenol of the control showed a 5% increase in production compared to the condition without stress. With the increase of drought stress, the amount of N and P in the plant decreased. Also, the lowest Ca was obtained in the control treatment and the combined application of 2 mM glycine amino acid and 4 kg/ha of humic acid. In general, both humic acid and glycine betaine treatments were effective in reducing damage caused by stress, and the simultaneous application of both substances in appropriate concentrations was effective in increasing nutrients, proline content and antioxidant activity under drought stress conditions.