نشریه علوم سبزی ها
سال هفتم شماره 1 (پیاپی 13، بهار و تابستان 1402)

Water stress is the most prominent abiotic stress limiting agricultural crop growth and productivity. Deficit irrigation stress as a consequence of the progressive decrease in water availability has been a hot topic regarding food security during the last two decades. Growth and development of plants are influenced by reduction in turgor that results in decreased nutrient acquisition from dry soil. Due to the threat of climate change, there is a need to limit the use of water resources in arid and semi-arid climates. It is therefore important to find new approaches to avoid crop productivity losses in ‘limited fresh-water’ areas. Eggplant (Solanum melongena) is an important non-climacteric fruit grown in tropical and subtropical regions. The estimated total world production for eggplants in 2019 was 51287210 tons. Foliar application of agro-chemicals has widely been used in agriculture as a rapid, low-cost and effective way for enhancing growth and productivity of many vegetable crops under water deficit conditions. Ca is an essential macronutrient for plant growth and development, and is considered as an important intracellular messenger, mediating responses to hormones, stress signals and a variety of developmental processes. Amino acids are important bio-regulators which have promotive effects on plant growth and productivity. Cysteine is the precursor molecule of glutathione, the predominant non-protein thiol, which plays an important role in plant stress responses.

The field experiment was carried out at the Research Farm of Agriculture Faculty, University of Zanjan, Iran, during 2021. The experiment was performed using a split plot based on a randomized complete blocks design with three irrigation regimes (60, 80 and 100 %ETc) as the main plot and foliar spray of two levels of calcium lactate (CaL) (1 and 2 g L-1) and L-cystein (Cys) (0.15 and 0.5 %) as the sub-plot in three replicates. Distilled water was used as a control. Eggplant (cv. Greta RZ) seedlings were transplanted at the 4-5 leaf stage with 35 cm spacing within row and 100 cm spacing between rows. After plant establishment, eggplants were sprayed with different concentrations of CaL and Cys at 6-7 leaf stage. Second and third times of foliar application were performed at 10 and 20 days after the first spraying. Irrigation treatments were applied one week after the first spraying. Number of branch per plant, plant height and leaf area were measured as growth parameters in harvest stage. Total chlorophyll and carotenoid contents, proline, leaf relative water content, stomatal conductance and electrolyte leakage were measured as physiological characteristics. Also plant fruit yield and water use efficiency (WUE) were evaluated.

As the results showed, plant growth, physiological indices and WUE significantly affected by deficit irrigation. Water deficit stress significantly reduced plant length, leaf area and chlorophyll content, and increased carotenoid content. Decreased plant growth may be due to limited cell division, cell enlargement due to turgor loss, and inhibition of various growth metabolites. Foliar spray of CaL and Cys improved plant growth, fruit yield and physiological indices. Leaf relative water content (LRWC) is among the main physiological criteria affecting plant water relations and have been used for assessing drought tolerance. Based on the findings, deficit irrigation caused a significant reduction in LRWC and stomatal conductance, which is due to the reduction of leaf water potential and the decrease of root water absorption rate under drought conditions. The highest value of LRWC and stomatal conductance were obtained in plants sprayed with CaL 2 g L-1 under irrigation 100 %ETc. Free proline is one of the most important osmolytes whose accumulation is a common physiological response to drought stress in higher plants and is probably associated with osmotic regulation and membrane stability under stress condition. WUE, the physiological parameter of crop, describes the relationship between plant water consumption and dry matter production. The proline content and WUE increased under deficit irrigation treatments; in particular with sever deficit irrigation (60 %ETc). The maximum proline content and WUE were observed in plants treated with CaL 2 g L-1 and Cys 0.5 % under deficit irrigation of 60 %ETc. The results showed that deficit irrigation led to a significant increase in electrolyte leakage compared to control, and foliar application of CaL and Cys decreased electrolyte leakage under normal and deficit irrigation conditions. Water deficit stress caused significant reductions in yield. The highest fruit yield was obtained under irrigation of 100 %ETc along with application of CaL 2 g L-1 and Cys 0.5 %.

Water deficit has been shown to adversely affect plant growth and fruit yield. Foliar application of CaL and Cys positively improved plant growth, physiological traits and fruit yield, as well as WUE. According to the results, application of CaL 2 g L-1 or Cys 0.5 % can be proposed to improve growth, fruit yield and WUE of eggplant.

The agriculture section as a subsection of our economy receives the most impact under the climate fluctuations. Climate change is an unsustainable factor affecting the yield of agricultural crops. Therefore, agricultural production, especially rainfed cultivation, has a high correlation with climatic factors. Climate change, in addition to affecting the production of agricultural crops, affects the sustainability and performance of agricultural products by influencing water resources. Agricultural product performance forecasting is one of the management tools in agricultural sector planning and policy making. The purpose of the current study was to evaluate the yield and production rate of three summer crops including cucumber, tomato and watermelon due to climate change in Khuzestan province and their prediction for the years 2025 to 2100.

In order to evaluate the reaction function of summer crops yield in Khuzestan province, meteorological data including precipitation, minimum temperature, maximum temperature and relative humidity of 13 meteorological stations including Ahvaz, Izeh, Andimeshk, Mahshahr, Behbahan, Dezful, Azadegan, Ramhormoz, Shushtar, Masjed Soleiman, Omidieh, Shadegan and Shoush was collected during the years 1991 to 2020. Excel and SPSS software were used to calculate and analyze the indicators. The climatic indices of Khuzestan province were divided into two climatic regions. Region (1) included Ahvaz, Mahshahr, Behbahan, Shoushtar, Omidie, Shadegan and Shoush, and region (2) included Dezful, Azadegan, Ramhormoz, Masjed Soliman and Andimeshk. The yield function of three products including cucumber, tomato and watermelon at two regions was estimated using panel data and Eviews software. Then, the yield and production rate of crops were predicted using the climate forecasting scenarios for the years 2025 to 2100.

The results showed that temperature had a negative and significant effect on the yield of tomato in region (1) and region (3), but it had a positive and significant effect on the yield of region (2). Rainfall had a negative and significant effect on the yield of tomato in region (1). But rainfall had a positive and significant effect on the yield of crops in region (2) and (3). Humidity had a positive and significant effect on tomato in region (1) and (2), but it had a negative effect on region (3). Temperature had a positive and significant effect on cucumber yield in region (1) and region (3). But it had a negative effect on the yield of cucumber in region (2). Rainfall had a positive and significant effect on cucumber yield in region (1) and (3). But it had a negative effect on the performance of region (2). Humidity also had a positive effect on the performance of cucumber in region (1), but it had a negative effect on the performance of region (2) and (3). Temperature had a negative and significant effect on watermelon yield in region (1) and (3), but it had a positive effect on watermelon yield in region (2). Rainfall had a negative and significant effect on the yield of watermelon in region (1), but it did not have a significant effect on the yield of region (2) and (3). Humidity had a negative and significant effect on the yield of watermelon in region (1) and (3), but it had a positive and significant effect on the yield of region (2). Also, the results showed that the highest percentage of yield changes in climate scenarios were related to cucumber in region (3) and watermelon and tomato in region (2). The results of forecasting the production rate of selected crops during the years 2100-2025 showed that the highest production rate was related to tomato in region (2), watermelon in region (2) and watermelon in region (1). Based on the results, during the years 2100-2025, the cultivated area of tomato crop in region (1) showed a more downward trend, but the cultivated area of cucumber crop in region (1) showed a more upward trend.

The results of yield forecasting until year 2100 showed that cucumber crop in region (3) and watermelon and tomato crops in region (2) have respectively higher increase rate of yield. Also, results demonstrated that in region (2), tomato and watermelon have higher production rate, respectively. Given to adverse effects of climate change on the production of studied crops and in order to prevent considerable reduction of production rate, solutions should be provided to adapt more to climate conditions, such as changing the cultivation pattern, optimal management of resources and production of varieties resistant to climate change. Therefore, according to the obtained results, it could be stated that region (2) has a relative advantage in the production of watermelon and tomato crops.

Okra (Abelmoschus esculentus) is a tropical and sub-tropical vegetable that is mainly grown by transplantation. Technological advances in agriculture have also contributed to the progress of the transplanting industry because they have reduced the cost of transplant production. Arbuscular mycorrhizal fungi (AMF) have symbiotic relationship with many plants’ root and their importance in growth and yield improvement has been proven. Mycorrhizal symbiosis is one of the most common symbiosis in plants. The main advantage of AMF for host plants is the expansion of the root penetration zone. Also, seaweed extract (SWE) acts as a bio-stimulant to plant growth enhancement. These products are widely used in improving agricultural sustainability and can actually facilitate the production process by reducing environmental effects. And, the co-application of AMF and SWE could be attributed to promoting the growth and yield of agricultural crops.

In order to study the effect of SWE foliar application and AMF inoculation on okra transplants, a factorial experiment was conducted based on a completely randomized design with two factors and four replications under greenhouse condition. The first factor was AMF (Glomus mosseae) inoculation at two levels included 0 (as control) and 5 g kg-1 and the second factor was SWE (Ascophyllum Nodosum) foliar application at four levels included 0 (as control), 1, 2 and 4 g L-1. The morphological traits of the transplants such as plant height, number of leaves, length and width of the leaves, fresh and dry weight of the root and shoot, and stem diameter were measured. Also, in order to assess physiological responses of transplants to used treatments, some important traits such as photosynthesis pigments content, total soluble carbohydrates, total soluble proteins, total antioxidant activity and some macro- and micronutrients were evaluated.

The results showed that the morphological, physiological, and biochemical characteristics, as well as the nutrient content of okra were significantly affected by SWE spraying and AMF inoculation. These treatments improved the growth parameters, photosynthetic pigments content, osmolytes (total soluble carbohydrates and total soluble protein), total antioxidant activity, and macro and micro-nutrients of okra transplants. The foliar spraying of 4 g L-1 SWE along with AMF increased the stem diameter, plant height and leaf length by 72, 85 and 55%, respectively, compared to the control plants. AMF inoculation improved the leaf width by 12.83% compared to control. Foliar application of SWE at 4 g L-1 concentration increased the leaf width by 25% compared to control. The treatment of 4 g L-1 SWE along with AMF inoculation caused an increase in fresh and dry weight of root by 132.83 and 204.54 %, respectively. The highest content of chlorophyll a (36.51 and 35.79 mg g-1 FW) was observed in transplants treated with SWE 2 and 4 g L-1 and AMF, respectively, and the lowest content (12.01 mg g-1 FW) was observed in control. The highest content of chlorophyll b (22.21 mg g-1 FW) was obtained in transplants treated with SWE 4 g L-1 and AMF, and the lowest value was recorded in control (6.51 mg g-1 FW). Foliar spraying of SWE and AMF inoculation led to a 2.7-fold enhancement in total soluble protein compared to control. The highest antioxidant activity (35.89 %) was recorded in transplants treated with SWE 2 g L-1 and the lowest value (25.44 %) was for control plants.

The results of the current study have shown that application of SWE and AMF as separate or combined treatments led to a significant improvement in okra transplants morphological characteristics such as plant height, leaf length, number of leaves, stem diameter, leaf width, and stem and root fresh and dry weight, as well as enhanced physiological traits such as protein content, chlorophyll a and b content, antioxidant activity rate, carbohydrate and carotenoid content, and the amounts of macro- and micro-nutrients. Based on obtained results of this study, foliar application of SWE at concentration of 4 g L-1 along with AFM inoculation could be recommended as useful treatment to produce okra transplants with suitable morpho-physiological characteristics.

Bell pepper is a popular agricultural product, not only for its economic value but also for the nutritional value of its fruits, which are enriched source of natural colors and antioxidant compounds. During developmental stages, the pepper fruit serves as a significant carbon sink, exerting a notable influence on the growth and carbon levels of adjacent organs including buds, flowers, and immature fruits. The occurrence of abortion and the abscission of flowers and immature fruits can lead to substantial alterations in crop output during the growth cycle. The fruiting patterns are influenced by both environmental conditions and the quantity of fruits. When specific fruits attain ripeness, their rate of sink power decelerates. Consequently, a novel fruit set initiates its growth, thereby initiating a fresh cycle of fruit production. Consequently, the presence of unpruned plants leads to flash fruiting, characterized by periodic variations in fruit output, thereby constituting a significant challenge in greenhouse cultivation of bell pepper. The purpose of the current experiment was to investigate the effect of fruit pruning and harvest sequence on the yield and qualitative characteristics of two common bell pepper cultivars grown under greenhouse condition.

This study was conducted in a greenhouse located in the east of Isfahan during 2019. A factorial experiment was carried out based on completely randomized design with four replications. The experiment factors included a) fruit pruning at four levels: Non-pruning (control), and 10%, 20% and 30% pruning, b) pepper cultivar at two levels: Lumos yellow cultivar (from Syngenta company) and Lorka red cultivar (from Seminis company) and c) harvest sequence at four levels: first, second, third and fourth. Seeds sowing was done on October 23, 2019. Seeds were sown in transplant trays filled with a mixture of peat moss and perlite. Subsequently, on December 1, 2019, seedlings were transferred to the primary substrate, when they had developed four to six true leaves. The individuals were relocated to the greenhouse. During this period, the pepper plants were pruned and secured to the taut wires of the trellis. Furthermore, the greenhouse temperature was adjusted on 26-28 °C as day temperature and 16-18 °C as night temperature. Irrigation was implemented in a strip-wise manner. During this research, the effect of fruit pruning and cultivar on morpho-physiological traits and also, the effect of fruit pruning and harvest sequence on performance characteristics of pepper plant were investigated.

Results indicated that pruning 10 % led to an increase in seed weight, flesh thickness and L* color index of yellow cultivar. The effect of pruning on fruit weight of yellow cultivar during successive harvests revealed that unpruned plants had relatively acceptable fruit weight on first harvest, but the weight of the fruits decreased over the time during subsequent harvests, indicating when fruit pruning is not done the number of fruits increases, and as a result, the weight of each fruit decreases. While, pruning 30% was able to maintain the fruit weight from the first harvest to the fourth harvest. Maintaining the fruit weight during successive harvests is highly important for pepper farmers. Reduction of fruit number through the pruning leads to prevention of fruit weight loss during successive harvests followed by higher fruits marketability. The effect of pruning on fruit weight of red cultivar during different harvests revealed that unpruned and pruned plants at 10 % level did not produce any fruits at first harvest, and fruit production initiated at second harvest leading to lower yield performance. The highest fruit diameter of yellow cultivar during successive harvests was recorded at pruning 30 %. Also, the highest fruit length of red cultivar was measured at first harvest and pruning 30 %. All pruning levels increased the total weight of first grade fruits of red cultivar, so that the lowest value of this trait was recorded in unpruned plants.  

Fruit pruning appears to improve the source/sink relationship in pepper by increasing fruit yield and weight as well as fruit qualitative characteristics so that the red cultivar outperformed the yellow cultivar in most growth and qualitative traits, and pruning 10 and 20 % were more positively effective on fruit firmness and size (diameter and length) comparing to other levels. Based on results, it is recommendable to conduct pruning at levels of 10 and 20 % on two bell pepper cultivars, namely yellow (Lumos) and red (Lorka), in order to enhance the fruit yield and qualitative characteristics.

Cultivation of summer crops is the high cost process, so the produced crops should have suitable quantitative and qualitative characteristics to compensate production costs. Selection the plants with the best morpho-physiological characteristics and productivity rate can lead to enhance economic efficiency and resistance rate to biotic and abiotic stresses. With population growth, demand for eggplant as an excellent source of iron, calcium, potassium, phosphorus, and vitamins A and B has increased. In addition to use as food, eggplant also has medicinal characteristics leading to its consumption for medicinal purposes. Eggplant is considered as widely cultivated crop with edible fruits in tropical, subtropical and warm regions, especially in Southern Europe and South America. The total cultivated area of eggplant is about 1.65 million hectares, its production rate is about 48.5 million tons, and its average yield is about 29.3 tons per hectare, worldwide. China, India and Iran are respectively the top producers of this crop with 28.8, 12.2 and 1.3 million tons production rates. Khuzestan, Hormozgan, Tehran, Fars, Sistan and Baluchistan, Razavi Khorasan, Bushehr, Jiroft and Kahnuj are some regions in Iran with the highest cultivation and production rate of eggplant.

The adaptability and stability of four advanced Iranian eggplant lines including D1, D7, D13 and BJ30, along with three controls including “Black Beauty” cultivar, Qasri Dezful landrace and round Brazjan landrace were studied based on randomized complete blocks design (RCBD) with three replications at five different locations during two years. Seedlings were transplanted at 4-6 leaf stage when their height reached to more than 10 cm. The field was irrigated before transplantation. The distance between rows was 60 cm and seedlings were transplanted at a distance of 75 cm in each row. The total yield was evaluated as a cumulative parameter for each plot from the beginning of fruiting to the end of the harvest period. Analysis of variance was performed using SAS software. Mean comparisons were conducted based on Duncan method at 1 % probability level. Stability analysis was performed by AMMI method.

The mean comparisons results demonstrated that the highest total yield was recorded in BJ30 line (34.08 ton ha-1), followed by D1 (33.72 ton ha-1) and D7 (31.42 ton ha-1) lines. Total yield in Karaj region (58.39 ton ha-1) was higher than other studied regions (Jiroft with 34.34, Dezful with 25.52, Orumieh with 22.74 and Qarakhil with 14.49 ton ha-1, respectively). The highest yield was observed in B J30 line and Borazjan landrace cultivated in Karaj region and the lowest yield was recorded in D7 line, ‘Black Beauty’ cultivar, D13 line and Borazjan landrace, all cultivated in Qarakhil region. Based on AMMI analysis, D1 and D7 were the most stable lines with the high yield which could be recommended for cultivation in all studied regions. The uniformity of the D7 line as a pure line has given it the ability to introduce a promising line. As reported by several researchers, the difference between total yields of eggplants cultivated in different studied regions of this experiment could be related to different climates and meteorological parameters of these regions. The significant interaction effect of region and genotype on total yield indicated that different eggplant genotypes had different reactions to changes in meteorological parameters, and on the other hand, the lack of significant interaction of year and genotype on this trait demonstrated that genotypes reacted the same way to different years. AMMI model was useful in interpreting the results and the model was able to fit the observed data well, which was in line with those reported by several researchers.

Given the high stability and total yield of D1 and D7 lines, they could be recommended for cultivation in all studied regions. Among the studied regions, Karaj with 58.39 ton ha-1 had the highest total yield, and on the other hand the lowest value of this trait was recorded in Qarakhil region. The BJ30 line has special compatibility with the Karaj region and is recommended for this region. BJ30 had completely sweet fruits and was significantly different compared to all controls. D1 had green cylindrical fruits with the best taste and the least bitterness comparing to the other lines.

The stability of soil structure has a great effect on plant growth. In fact, soil structure is considered as key factor for determination of soil quality. Soil structure can influence the growth and development of plants through maintaining soil water, soil elements and air, etc. Water stress is one of the most important factors limiting the physiological and nutritional growth of plants, which will lead to a decrease in biomass and yield. Fenugreek L. (Fuenum graceum) is a plant belonging to the legume family, which is widely grown in temperate and tropical Mediterranean regions of Europe, Asia and Africa. In sustainable agricultural systems, any improvement should lead to an increase in production and a reduction in the destructive effect on the environment, which will ultimately lead to an increase in the sustainability of the agricultural system. One of these methods is the application of biofertilizers. Biofertilizers are a set of preservatives with a large number of beneficial microorganisms or their metabolic products. Mycorrhiza fungi and seaweed are two widely used biofertilizers.

This research was carried out as a factorial experiment based on completely randomized design with three replications, at research greenhouse of the Faculty of Agriculture, Lorestan University during the year 2021. Experimental factors included five levels of irrigation I60, I70, I80, I90, I100 (60, 70, 80, 90 and 100 % based on soil moisture depletion) and four levels of biofertilizer (control, vecozium algae 5 L ha-1, algae 5 L ha-1, mycorrhiza 50 g pot-1). At the end of the plant growth season (70 d after planting), the plants were harvested and characteristics such as soil moisture curve, mean weight diameter of soil aggregates, organic carbon, aerial part fresh weight, total chlorophyll, electrolyte leakage and proline were measured.

The results showed that under control condition (I100), the highest total chlorophyll content, mean weight diameter of soil aggregates and organic carbon were 19.72 mg g-1 FW, 0.77 mm and 1.72 % which were recorded in mycorrhiza treated plants. Using biofertilizers under stress conditions increased fresh weight of aerial part, total chlorophyll content, mean weight diameter of soil aggregates, organic carbon and soil moisture, and decreased proline and electrolyte leakage in comparison to control condition.The increase in soil moisture content due to the application of biofertilizers could be attributed to the hydrophilic properties of biofertilizers that lead to changes in soil properties. The increase in mean weight diameter of aggregate in this research could be related to the effect of fungal hyphae that develop inside the soil to form a skeletal structure and physically hold the primary soil particles together and improve soil aggregation. According to the results of this research, the amount of organic carbon decreased due to drought stress, while the application of biofertilizer alleviated this effect. The application of biofertilizers increased the growth characteristics of fenugreek plants under drought stress conditions, which could probably be attributed to their role in increasing root growth, photosynthesis rate and nutrients absorption rate. In stress conditions, excessive accumulation of reactive oxygen species in plant cells causes membrane damage and lipid peroxidation resulting in loss of semi-permeable characteristic of the membrane, reduction of membrane stability and increasing electrolyte leakage. Therefore, biofertilizers enhance plant resistance against stress condition by increasing membrane stability. The results of the present research showed that drought stress increases proline content in fenugreek leaves. Osmoregulation is one of the efficient mechanisms of plants to maintain cell turgescence under drought stress conditions which increases drought tolerance threshold through the accumulation of sugars and amino acids such as proline. The increase in the concentration of compatible osmolytes such as proline has been proven under the influence of environmental stresses such as drought.

The research results generally showed that drought stress causes a decrease in mean weight diameter of aggregate, organic carbon, fresh weight of aerial parts and total chlorophyll, and an increase in electrolyte leakage and proline content. Also, the use of biofertilizers under stress conditions can significantly improve plant and soil characteristics and alleviate stress negative effects.

The rapid growth of the world's population and food demand have made the use of agricultural inputs such as pesticides and chemical fertilizers inevitable to achieve the highest yield per unit area. The result of these activities during recent years has been the crisis of environmental pollution, especially the pollution of water and soil resources, which has entered the human food chain and threatened the health of human society. In order to overcome these issues and increase soil productivity rate and improve plant growth, fertilizers and biological compounds could be considered as efficient solution. Foliar application of organic compounds and bio-fertilizers is a suitable method for optimal nutrition of plants and is considered as one of the effective solutions to quickly improve the yield and quality of various crops. Therefore, this research was conducted with the aim of investigating the effect of foliar application of humic acid, amino acid, and extract of Otostegia persica, Artemisia abrotanum and Teucrium polium medicinal plants on the yield of tomato plant cv. “Sunseed 6189” under field condition.

In order to investigate the effect of foliar application of humic acid, amino acid and extract of Otostegia persica, Artemisia abrotanum and Teucrium polium medicinal plants on the yield and yield components of tomato (Solanum lycopersicum) cv. “Sunseed 6189”, an experiment was conducted based on randomized complete blocks design with 15 treatments including humic acid (2, 4 and 6 g L-1), amino acid (2, 4 and 6 g L-1), extract of Otostegia persica, Artemisia abrotanum and Teucrium polium medicinal plants (2 and 4 g L-1), mixed extracts (2 g L-1), humic acid + amino acid (4 g L-1) and control (water), and 3 replications in Kohnuj, Kerman province during 2018-2019. In this research, “Sunseed 6189” cultivar was cultivated. The seeds were purchased from Nanhenz Company (Netherland). At the end of December, tomato seeds were sown in seedling trays contained peat moss substrate, and after 30 d, the seedlings were ready to be transferred to the field. After the establishment of seedlings (4-leaf stage), which took about 20 d, the foliar treatments were applied. Drip Irrigation was done according to the rainfall and climate conditions, so that all experimental units were watered twice per day, one time in the morning and the other in the evening for 20 min. Duration of daily watering was gradually increased to 1 h as the seedling grew. At the end of the experiment, plant fresh and dry weight, carotenoid, chlorophyll a, chlorophyll b and total chlorophyll content, fruit number, length and diameter, yield per plant, marketable yield and total yield, tissue firmness, total soluble solid content, vitamin C, fruit carotenoid, fruit anthocyanin, potassium and phosphorus content were measured.

The results showed that the highest fresh and dry weight of plant was observed in control (water-treated plants) (1150 and 200 g). Also, the highest number of fruits per plant (30.3) and yield (2.51 kg plant-1 and 50.3 ton h-1) was related to humic acid + amino acid (4 g L-1) treatment. The results of previous researches demonstrated that humic acid increases the amino acids and proteins content of plant tissues leading to enhancing the plant growth and yield performance. Also, the results of this study showed that using combined treatment of humic acid and amino acid can amplify this positive effect, so that the fruit diameter and length, and total yield of treated plant with humic acid + amino acid was significantly higher than those of control. The lowest anthocyanin content of fruit (3.212 μmol g-1) was for combined treatment of humic acid + amino acid. The highest tissue firmness was recorded in fruits treated with mixed extracts. Based on studies, using medicinal plants extract can lead to lower activity of cell wall degrading enzymes resulting in more tissue firmness. According to obtained results, amino acid treatment improved qualitative characteristics of tomato fruit and increased its nutrients content. Increasing the absorption rate of N, P, K and some micro-nutrients induced by amino acids foliar application was reported in different studies. Amino acids improve the efficiency of root absorption rate resulting in higher macro and micro-nutrients content of plant cells.

Based on the obtained results, humic acid + amino acid (4 g L-1) and the mixed extract of Otostegia persica, Artemisia abrotanum and Teucrium polium medicinal plants (2 g L-1) were the best treatments to increase yield and yield components, and enhancing the fruit quality. Therefore, using these treatments during the cultivation of tomato plant cv. “Sunseed 6189” is recommendable.

Button mushroom (Agaricus bisporus L.) is considered as valuable source of nutrients and a crop with medicinal characteristics due to its high amounts of vitamins, protein and bio-active compounds. The lack of cuticle layer in button mushroom has made it sensitive to microbial agents and browning disorder. Due to high sensitivity rate of button mushroom to microbial corruption, different methods such as coating, modified atmosphere packaging and treatment with anti-microbial solutions are used to reduce corruption speed and post-harvest wastes. The essential oils of medicinal plants are part of plant secondary metabolites which have anti-microbial, anti-cancer and antioxidant characteristics and can eliminate reactive oxygen species in plant cells and tissues. The positive roles of essential oils of medicinal plants in increasing the maintainability of different crops such as apple, banana and button mushroom during cold storage have been proven in various studies. According to reports using essential oil of some medicinal plants such as Cinnamomum zeylanicum, Mentha pulegium and Zataria multifloraat post-harvest stage can extend crops shelf-life and maintain their qualitative indices. The purpose of the current study was to evaluate the influence of using the essential oil of some medicinal plants in packaging containers on some of most important post-harvest characteristics of button mushroom.

The current study was carried out at Ilam University during 2022-2023. In this research, the influence of essential oil of some medicinal plants including Thymus spicata, Mentha piperita and Satureja bachtiarica at different concentrations (0, 500 and 1000 ppm) on some qualitative indices of button mushroom such as tissue firmness, cap opening rate, radical scavenging activity, organoleptic properties and antioxidant enzymes activity was investigated during cold storage at 4 °C. The post-harvest characteristics were evaluated at three different storage durations including 0, 4 and 8 d after harvesting.

According to obtained results, the weight loss increased and tissue firmness, total soluble solid content and total acidity decreased with increasing storage duration. All treatments could significantly reduce weight loss and maintain tissue firmness, total soluble solid content and total acidity of mushrooms except T. spicata treatment at 1000 ppm concentration. The recorded data on 8 d, showed that the highest H2O2 content and the lowest radical scavenging activity was related to T. spicata treatment and control while the mushrooms treated with S. bachtiarica at 1000 ppm concentration had the lowest H2O2 content and the highest radical scavenging activity. Results demonstrated that cap opening remarkably decreased and tissue firmness and marketability of mushrooms maintained by using essential oils of S. bachtiarica at two concentrations of 500 and 1000 ppm and M. piperita at concentration of 500 ppm. Results of organoleptic test indicated that using essential oil of S. bachtiarica and M. piperitaat concentration of 500 ppm led to enhance marketability and acceptability of mushrooms as well as improved their taste and odor. The lowest evaluated acceptability rate by panel members was related to mushrooms treated with essential oil of T. spicata and M. piperita due to change in their taste and appearance of brown spots. In this study, maintaining qualitative characteristics of button mushroom induced by treatment with essential oil of medicinal plants could be related to two main factors included anti-microbial and antioxidant characteristics of essential oils. Based on several reports, anti-microbial properties of essential oil and extract of medicinal plants can cause lower respiration rate and water loss in treated crops during storage. Also, the reduced amounts and activity rate of reactive oxygen species was observed in different horticultural crops treated with essential oils during post-harvest stage. In the current study, increasing catalase and peroxidase enzymes activity, maintaining total phenol and water content and decreasing polyphenol oxidase enzyme activity could be considered as main reasons for extending shelf-life of mushrooms treated with essential oil of S. bachtiarica and M. piperita.

Based on obtained results of the present study, using essential oil of S. bachtiarica as natural and low-risk compound for maintaining the quality and extending shelf-life of button mushroom during storage at 4 °C is recommendable.

Mentha spicata is one of main cultivated crops in temperate, Mediterranean and sub-tropical regions. This plant is an enriched source of vitamins and mineral nutrients. Also, it is used for various medicinal purposes such as treatment of gastrointestinal and respiratory diseases. Nowadays, among the plant stresses, heavy metals toxicity is considered as dominant and global issue damaginh the environment. Heavy metals toxicity is mainly caused by human activities such as mining, irrigation with wastewater and using the products with high content of heavy metals. Heavy metals can negatively affect soil and water quality and human health even in low concentrations. Copper (Cu) is one of most dangerous heavy metals which threatens the human health and reduces the crops quality. Pseudomonas putida and Pseudomonas fluorescens bacteria are plant growth-promoting bacteria. They can stimulate growth and enhance plant resistance to different environmental stresses such as heavy metals toxicity. The aime of this study was to alleviate the adverse effects of Cu heavy metal toxicity on some of most important characteristics of Mentha spicata through the application of bacterial treatments.

In order to evaluate the influence of bacterial treatments including Pseudomonas putida, Pseudomonas fluorescens and putida + P. fluorescens on copper chloride toxicity stress at three levels including 0 (control), 100 and 200 mg kg-1 soil, a factorial experiment was carried out based on completely randomized design with four replications, at Department of Horticultural Science and Engineering of Maragheh University, during 2019. Some of most important characteristics of Mentha spicata such as plant height, aerial part fresh weight, root fresh weigh, photosynthetic pigments content, malondialdehyde (MDA) content, free proline content and antioxidant enzymes activity were measured under stress conditions.

The results of the current study showed that copper chloride toxicity stress had a negative effect on plant growth parameters such as plant height, fresh weight of aerial parts and root as well as photosynthetic pigments content, while the use of Pseudomonas putida and Pseudomonas fluorescens bacteria significantly alleviated these negative effects through increasing the activity of antioxidant enzymes and proline content. The highest fresh weight of aerial part (5.65 g) was recorded in plants treated with putida + P. fluorescens under control condition. The lowest weight of aerial part (2.95 g) was measured in plants treated with P. fluorescens under stress level of 200 mg kg-1 copper chloride. According to reports, the growth-promoting bacteria improve plant growth parameters by reduction of ethylene concentration in plant tissues under heavy metals stress conditions. Also these bacteria, directly increase plants growth rate through the increasing solubility of nutrients such as N and P in soil and biosynthesis of plant growth regulators and phytohormones. The highest SOD activity (35.55 U g-1 min-1) was measured in plants treated with P. putida + P. fluorescens under stress level of 100 mg kg-1 copper chloride.

Based on the results of the present study, copper chloride stress decreased stem height, fresh weight of aerial parts, fresh weigh of roots and the leaf photosyntheyic pigments content (chlorophyll a and b), and increased malondialdehyde and proline content in Mentha spicata plants. However, the use of P. putida and P. fluorescens bacteria alleviated the negative effects of heavy metal stress by increasing the activity of antioxidant enzymes (SOD and GPX) and proline content and reducing the amount of MDA (MDA is considered as indicator for cell membrane damages rate). Therefore, using P. putida and P. fluorescens bacteria treatment could be introduced as efficient and widely used technique to enhance tolerance rate of Mentha spicata against copper chloride toxicity stress.

Pectobacterium carotovorum carotovorum (Pcc) is one of the main causes of soft rot disease in many economically important vegetables and tubers such as carrot, cabbage, potato, onion, cucumber, eggplant, garlic, bell pepper, radish, sweet potato, squash and tomato. The use of chemical bactericides is not suitable to control soft rot bacteria due to their toxic side effects and the emergence of resistance in bacterial populations. The use of bio-control bacteria to inhibit bacterial pathogens such as Pcc is a practical and useful method to overcome the issue. In this study, in order to control this disease with the help of bacterial biological control agents, some bacteria were isolated from rhizosphere of vegetables and potato. The aim of this study was to find bacteria with different bio-control mechanisms which are able to inhibit different isolates of Pcc. On the other hand, these bacteria (with different bio-control mechanisms) were combined to investigate the possibility of increasing their bio-control ability in a mixed manner.

12 rhizospheric bacteria were isolated from vegetables and potato. Antibacterial properties were evaluated using chloroform vapor method. Also, 12 bacteria were isolated from rhizosphere of vegetables and potato by minimal medium to evaluate the quorum quenching (QQ) ability. Chromobacterium violaceum CV026 biosensor was used to assess QQ activity in bacteria. There were two types of bio-control tests: the first case was the application of bacteria individually and the second case was the mix of bacteria with different bio-control mechanisms, antibacterial property and QQ activity, and its application against two strains of Pcc including PccK and PccM. At first, before doing the second bio-control test, interaction test between bio-control bacteria was performed by culturing two bacteria perpendicular to each other on solid medium. Bio-control test of Pcc on plant tissues (potato tubers, carrots and bell peppers) was performed by calculating the weight of rotting tissue in comparison with the control (containing Pcc alone). Classical and molecular bacteriological tests were performed to detect these bacteria.

Among rhizospheric bacteria with antibacterial properties, A10 isolate had a large inhibitory halo, 16.67 mm, against one strain of Pcc (PccK) and it had the ability to bio-control of PccK on vegetables and potato tubers. Among bacteria, only SS5 isolate showed QQ ability in both biosensor and bio-control tests. A10 and SS5 were detected as Pantoea and Pseudomonas sp. respectively. Pseudomonas SS5 had moderate bio-control activity against two Pcc strains with QQ mechanism as inhibition percentage on potato tubers rot for PccM and PccK were 53.92 % and 68 %, respectively. Pantoea A10 with antibacterial activity which had low or high bio-control properties against Pcc strains as inhibition percentage on potato tubers rot for PccM and PccK were 5.81 % and 91.33 %, respectively. The bio-control effect of A10 and SS5 bacteria against Pcc strains on carrots and bell peppers was better than potatoes. The interaction of two bacteria on solid medium, SS5 and A10, was not visible as a transparent area at their intersection, so they did not show an inhibitory effect against each other. Therefore, it is possible to use combination of two bacteria, A10 and SS5, for bio-control tests. The results showed that the bio-control ability of these two bacteria in the mixed state was much higher than the single application of each bacterium. In mix of two bio-control bacteria, disease was further reduced at least for PccM, in other words, the bio-control property was increased. In the case of the combination of two bacteria against PccM, compared to SS5 and A10 application alone, it produced 2.21 and 4.53 times less rot tissue, respectively.

There are two main bio-control mechanisms in bio-control bacteria for Pcc rot reduction including bacteria with antibacterial properties and bacteria with QQ abilities. In this study, for the first time, it was found that two bacteria with different bio-control mechanisms, including Pantoea and Psudomonas sp., are able to control Pcc separately and in combination. For the first time, the improvement of the bio-control properties of these two bacteria in combination with each other was identified. It was also found that the effect of these different bio-control bacteria on the control of each Pcc isolate and even each host of vegetables or potato tuber could be different, so that one Pcc isolate was sometimes completely inhibited and the other Pcc isolate was not affected by the bio-control bacteria. Because QQ mechanism disrupts the basic common physiological pathways in all Pcc isolates. So, this mechanism in bio-control bacteria apparently has a more general effect than the antibacterial effect.

Water shortage is an integral part of our current agriculture, and water stress is one of the most destructive environmental factors which adversely affects agricultural production worldwide. According to several studies, water deficit causes reduction of vegetative growth, leaf area, plant height, dry weight, photosynthesis rate, chlorophyll content, stomatal conductance, enzymatic activities, protein biosynthesis and amino acids accumulation in horticultural plants. Increasing reactive oxygen species (ROS) rate and activity is the one of most damaging effects of drought stress. Cucumber is a tropical crop with high water requirement. Wide leaves and shallow roots have made it a drought-sensitive crop. Based on reports, water deficit and drought stress can seriously affect yield performance and qualitative characteristics of cucumber. Measurements are needed in different aspects to overcome challenges associated with water deficit and water stress in cropping systems. So, in this study glycine amino acid were applied for its possible role under mild water shortage effects on cucumber growth characteristics.

In order to investigate the influence of glycine amino acid application on alleviation of negative effects of deficit irrigation, a greenhouse experiment was conducted based on completely randomized design with four replications. Treatments were assessed at six levels including 60 % FC, 70 % FC, 80 % FC, 60 % FC + glycine 500 mg plant-1, 70 % FC + glycine 500 mg plant-1 and 80 % FC + glycine 500 mg plant-1. Some of most important morphophysiological and biochemical characteristics of cucumber plants such as stem length, stem dry weight, leaf number, leaf area, internode length, growth period duration, fruit number, fruit set, vitamin C, chlorophyll index, total antioxidant, proline, catalase, peroxidase and polyphenol oxidase enzymes content were evaluated.

Result showed that deficit irrigation and glycine amino acid application significantly influenced morphophysiological and biochemical characteristics of cucumber plant. It was observed that vegetative traits including leaf number, leaf area index, stem length and dry weight, length of internode, growth period duration, chlorophyll index, and fruit characteristics including vitamin C content and fruit set were significantly reduced by deficit irrigation levels particularly at 60 % FC. The highest fruit number (86.5) was recorded under 70 % FC and application of glycine. In contrast, antioxidant capacity, proline, catalase, polyphenol oxidase and peroxidase enzymes content increased under 60 % FC. Glycine application could properly alleviate the negative effects of deficit irrigation on plant growth and yield. Studies have shown that glycine application maintains chlorophyll content and photosynthesis rate of plants under stress condition, which is mostly related to increasing stomatal conductance and carboxylation efficiency. Generally, water deficit reduces the yield performance of crops. And, this reduction could be correlated with decreasing leaf area and disruption of nutrients absorption. According to results of this study, maintaining the photosynthetic pigments caused by glycine application resulted in enhanced photosynthesis rate leading to higher yield comparing to control under deficit irrigation conditions.

Generally, the results of the current study demonstrated that deficit irrigation at level of 60 % FC caused induction of drought stress conditions. Induction of water deficit and drought stress higher than 70 % FC led to sever physiological and biochemical changes in cucumber plants resulting in considerable reduction of yield performance and qualitative characteristics. Water deficit increased proline content and antioxidant capacity (increasing the activity rate of antioxidant enzymes including catalase and peroxidase) of cucumber plants. Soil application of glycine amino acid alleviated the adverse effects of deficit irrigation. Because the highest fruit number was counted in 70 % FC + glycine 500 mg plant-1 treatment (with no significant difference with the control (80 % FC)), this treatment could be recommended to growers to save water consumption with no significant changes in yield performance comparing to control level.