Growing vegetables
Z. Khalili; F. Nekounam; T. Barzegar; Z. Ghahremani; M. Farhangpour
Abstract
IntroductionTomato (Solanum lycopersicum L.) belongs to the Solanaceae family, which is one of the most widely cultivated and economically important vegetables in the world, which is an excellent source of ascorbic acid and has high antioxidant capacity against oxidative damage caused by free radicals. ...
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IntroductionTomato (Solanum lycopersicum L.) belongs to the Solanaceae family, which is one of the most widely cultivated and economically important vegetables in the world, which is an excellent source of ascorbic acid and has high antioxidant capacity against oxidative damage caused by free radicals. Ascorbic acid (AsA) is a water-soluble vitamin that plays a key physiological role in scavenging reactive oxygen species (ROS), and enzyme cofactor. Ascorbic acid is antioxidant and anti-stress agent, and also acts as a signaling molecule in some plant physiological processes and defense mechanisms. Positive roles of such antioxidants in scavenging or chelating the free radicals and activating the natural resistance against different biotic and abiotic stresses have been reported in several fruit trees. Calcium has a vital role for normal growth and development of plants due to an important role in balancing membrane structures, increasing nutrient uptakes and activates of metabolic processes. Calcium plays a vital role in maintains cell wall stability, integrity and determining the fruit quality. To our knowledge, however, little information is available regarding the interaction effect of ascorbic acid and calcium chloride on tomato. Thus, the aim of this study was to investigate the foliar application of ascorbic acid and calcium chloride on quality and antioxidant capacity of tomato fruit. Materials and MethodsTo study the effect of foliar application of calcium chloride (Ca) and Ascorbic acid (AsA) on growth, yield and fruit quality of tomato, the field experiment was carried out from June to September 2021 at Research farm of faculty of Agriculture, at the University of Zanjan, Iran. Each treatment was carried out with three replicates. Different concentrations of Ca (0, 0.3, 0.6 and 0.9 %) and AsA (0, 100, 200 and 300 mg.l-1) were sprayed three times (0, 15, 30 days after full bloom). Fruits were harvested at two harvests stage (orange and red color) and transferred to the laboratory on the same day. Flesh firmness was determined with penetrometer (model Mc Cormic FT 32), using an 8 mm penetrating tip. Results were expressed in kg cm-2. The pH values of solutions were monitored with pH meter. TSS was measured in the extract obtained from three fruit of each replicate with a digital refractometer Atago PR-101 (Atago Co., Ltd., Tokyo, Japan) at 20◦C. Total ascorbic acid content was expressed as mg per 100 g of juice. Antioxidant activity was measured using the free radical scavenging activity (DPPH) and calculated according to the following formula: RSA%= 100(Ac-As)/Ac. Statistical analyses were performed with SPSS software package v. 20.0 for Windows, and means comparison were separated by Duncan’s multiple range tests at p< 0.05. Results and DiscussionThe results showed that fruit harvested at red color stage had higher vitamin C, total soluble solid (TSS), total phenol, flavonoids contents and antioxidant capacity compared to fruit harvested at orange color stage. Foliar application of AsA and Ca had significantly improved tomato fruit quality. The highest value of TSS (4.9 °B), vitamin C (46.1 mg.100 ml-1), total phenol and flavonoids contents and antioxidant capacity (36%) was achieved with application of 300 mg.l-1 AsA and 0.9% Ca in fruit harvested at red color harvest time. The lowest value of pH and highest TA was observed in red color fruit treated with 300 mg.l-1 AsA and all Ca levels. Ca had significant effect on fruit firmness, which the highest fruit firmness was obtained from 0.9% Ca. The fresh tomato is an important source of ascorbic acid for human consumption. AsA significantly increased the amount of vitamin C in the plum and sweet pepper fruits. Increasing vitamin C content in fruits after treatment with Ca could be related to inhibiting action of calcium on the activities of ascorbic acid oxidase that use ascorbate as a substrate. The results indicated that treatment of Ca produced fruits with higher firmness compared to control and other treatments. Firmness and resistance to softening can be increased by the addition of Ca, due to interaction of calcium with pectate acid in the cell wall to form calcium pectate and retarding polygalacturonase activity. Differences in the percentage of TSS content at the time of harvest indicated the AsA and Ca effects on carbohydrate accumulation in fruits, which had different potential on respiration rates and consequently storability of plants. The antioxidant activity has positive correlation with total phenolic content, flavonoids and content of ascorbic acid. ConclusionsThe results of our research indicated that per-harvest foliar application of AsA and Ca improved fruit quality attributes including vitamin C, fruit firmness, TSS and antioxidant activity. These results suggest that AsA and Ca treatments, especially AsA 300 mg.l-1 and Ca 0.9%, may be proposed to improve fruit quality.
Medicinal Plants
Seyyed Amir Hossein Mousavi; F. Nekounam; Taher Barzegar; Zahra Ghahremani; Jafar Nikbakht
Abstract
Introduction
Physalis peruviana L. is a short perennial shrub that is a member of the Solanaceae family. These fruits have many benefits for human health because of their nutritional and bioactive compounds (vitamins (A, B, C and K), essential fats and etc.) and reduced the risk of diseases such as ...
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Introduction
Physalis peruviana L. is a short perennial shrub that is a member of the Solanaceae family. These fruits have many benefits for human health because of their nutritional and bioactive compounds (vitamins (A, B, C and K), essential fats and etc.) and reduced the risk of diseases such as cancer, malaria, asthma, hepatitis, dermatitis and rheumatism. Therefore, it has received special attention for cultivation all over the world. Increasing crop production and mitigating abiotic stresses are major challenges under extreme climatic environments and intense farming activities. Crop management strategies such as deficit irrigation can decrease soil evaporation, runoff, and plant transpiration, and increase water use efficiency (WUE) and water conservation. In addition to these practices, organic input, which includes the application of organic materials such as compost and humic substances, is an additional strategy that increases soil water retention and can potentially improve plant WUE. Water is crucial for agriculture and needs to be used effectively due to climate change and drought in Iran. For this reason, to adapt to water deficit scenarios, deficit irrigation applications are increasing in importance. Water availability is expected to be a growth limiting factor that would affect fruit yield in Physalis peruviana due to reduced flower set and elevated floral abscission rate.
Materials and Methods
In order to investigate the effect of humic acid on physiological characteristics, yield and fruit quality of Physalis peruviana under deficit irrigation conditions, a split plot experiment based on randomized complete block design with three replications was conducted during 2021. Treatments consisted arrangement of three levels of irrigation (starting irrigation at 100, 80 and 60% ETc (crop evapotranspiration)) and three levels of humic acid (0, 1.5 and 3 kg ha-1). The seeds of Physalis peruviana were sown in seedling trays contain peat moss. The seedlings were grown under normal conditions (25±2 °C/day and 20±2 °C at night with 60-65% RH). Plant height, total chlorophyll, fruit yield per plant, total soluble solid content, titratable acidity, vitamin C content and water use efficiency were measured. Statistical analyses were performed with SAS V9.3, and means comparison were separated by Duncan’s multiple range tests at p < 0.05.
Results and Discussion
The results showed that deficit irrigation significantly reduced growth, fruit yield, vitamin C and increased water use efficiency (WUE) and Total soluble solid content of Physalis peruviana. The soil application of humic acid significantly increased total chlorophyll, fruit quality and yield, and decreased leaf electrolyte leakage under normal and deficit irrigation, thus, the deficit irrigation 60 ETc% decreased the plant height by 18.6% and the fruit yield by 22.2% compared to irrigation 100 ETc%. The maximum plant length (200.3 cm), total chlorophyll content (2.42 mg g-1FW) and fruit yield (4793.3 kg ha-1) were observed in plants treated with 3 kg ha-1 humic acid under 100% ETc irrigation. The highest value of total soluble solid (12.6 B°), antioxidant activity (90.06 %) and WUE (1.23 kg m-3) were obtained with 3 kg ha-1 soil application of humic acid under deficit irrigation 60% ETc. The application of 3 kg ha-1 humic acid under 100 and 80 %ETc irrigation increased the fruit yield by 25% and 4%, respectively, compared to the control plants (non treated with humic acid) under irrigation100 ETc% and under deficit irrigation 60 ETc%, with decreasing 11% fruit yield, water consumption was saved by 40%. Soil and crop management practices that alter plant water and nutrient availability could affect the processes of crop evapotranspiration and WUE, which can influence the yield and fruit quality by changing the internal nutrient and water balance. Incorporating organic matter within a crop growth system either as leaf spray or soil mix is a complementary strategy to improve crop growth and WUE. By inducing antioxidant enzyme activities, HS could assist plants in stomata functioning, thereby closing stomata more efficiently under drought stress, which results in plant water conservation. The reason of the difference between WUE values probably appeared due to the differences on Physalis peruviana yield. WUE showed an upward trend with an increasing in irrigation.
Conclusion
Study results suggest that soil application of humic acid with increasing vitamin C, TSS and TA, improved fruit quality. According to the results, application of 3 kg ha-1 humic acid is suggested to improve fruit yield and quality of Physalis peruviana under normal and deficit irrigation conditions.
Growing vegetables
Parastoo Molaei; Taher Barzegar; Mohammad BabaAkbari Sari; Fatemeh Nekounam; Zahra Ghahremani
Abstract
Introduction
Excessive use of chemical fertilizers threatens the environment and leads to production of unsafe food products. Currently, the market share of organic vegetables is constantly increasing due to customer demand for safer and healthier food. Therefore, it is necessary to find alternatives ...
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Introduction
Excessive use of chemical fertilizers threatens the environment and leads to production of unsafe food products. Currently, the market share of organic vegetables is constantly increasing due to customer demand for safer and healthier food. Therefore, it is necessary to find alternatives instead of using chemical fertilizers in plant production.
Lettuce (Lactuca sativa L.), belongs to Asteraceae family is considered as one of the most popular salad vegetables as a cool season crop. It is also one of the most important vegetables due to its rapid growth and commercial value. Plant growth promoting bacteria promote plant growth directly by facilitating nutrient uptake through fixing nitrogen, solubiliszation of phosphorus, production of hormones and iron uptake. Arbuscular mycorrhizal fungi establish symbioses with plant roots which help to improve nutrient uptake by the host plant and alter its physiology to withstand external abiotic factors and pathogens. Arbuscular mycorrhizal fungi interactions with bacteria have been reported to enhance plant growth through phosphate solubilization, nitrogen fixation, increased AMF spore germination and colonization of plant roots. The potential of co-inoculation of these two organisms in promoting the growth of horticultural crops like tomato, strawberry, lettuce and spinach have also been reported.
Materials and Methods
In order to compare the effect of growth-promoting bacteria, mycorrhiza fungi and chemical fertilizers on morphological and physiological properties of lettuce (Lactuca sativa cv. New Red Fire), the experiment was carried out in a completely randomized design with three replications. Experiment treatments consisted of 14 treatments including three levels of potassium solubilizing bacteria (Pseudomonas vancouverensis, Pseudomonas koreensis, Pseudomonas vancouverensis + Pseudomonas koreensis) + 100% N and P, three levels of phosphorus solubilizing bacteria (Pantoea agglomerans, Pseudomonas putida and Pseudomonas putida + Pantoea agglomerans) + 100% N and K, and one level of potassium and phosphorus solubilizing combined bacteria (Pantoea agglomerans+ Pseudomonas koreensis+ Pseudomonas putida+ Pseudomonas vancouverensis) + 100% N, mycorrhiza fungi combination of three Glomus species (G. mosseae, G. etunicatum and G. intraradices) + 100% N and K and five chemical fertilizer levels (N100P100K100, N100P100K0, N100P0K100, N100P25K100 and N100P100K25) according to soil test results, and control treatment without bio-mineral fertilizers.
The “New Red Fire” lettuce seeds were surface sterilized with 0.5% (v/v) sodium hypochlorite for 10 min, and germinated at 20ºC. After germination, seedlings of similar size were transplanted singly into pots containing agricultural soil. Plants were grown under greenhouse condition of 60/70% (day/night) relative humidity, 15/18 °C (day/night) temperature. After a growth period of 75 days, plants were removed from the pots. The root system was separated from the shoot and washed to remove adhered soil. Root and shoot fresh weight, chlorophyll, vitamin C, anthocyanin, TA, TSS and nitrate contents were measured.
Results
The results showed that application of potassium and phosphorus solubilizing bacteria and mycorrhiza fungi significantly increased plant growth compared to control plant. The highest fresh shoot weight (increase of 42.3%) and crown diameter (increase of 14.4%) was obtained with application of combined potassium and phosphorus solubilizing bacteria treatment + 100% N fertilizer compared to control plants. Application of Pseudomonas koreensis + 100% N and P resulted in the maximum content of anthocyanin (increase of 62.2%) and total soluble solids (increase of 82.5%) compared to control plants. Ascorbic acid, a well-known antioxidant and organic compound, is an essential vitamin can be obtained from fruits and vegetables. The highest vitamin C content (32.3 mg 100 mL-1) was observed at plant treated with N100P100K100 fertilizer. The maximum titratable acidity content was obtained with application of Pseudomonas vancouverensis + 100% N and P, and combined potassium and phosphorus solubilizing bacteria treatment +100% N fertilizer. The nitrate content is an important quality index of leafy vegetables; low nitrate content is associated with enhanced quality. Application of chemical fertilizers significantly increased nitrate accumulation compared to biofertilizers and control plants, so that the minimum nitrate accumulation content was observed in control plant and combined potassium and phosphorus solubilizing bacteria treatment + 100% N fertilizer (21.14 µg g-1FW), respectively.
Conclusion
With continuous development of economy and society, people pay an increasing attention to the quality of fruits and vegetables. Improving the crop yield means that attention must also be given to improving vegetables quality, resulting in chemical fertilizer nutrition problem. To conclude, our study suggested that after the control treatment (without using any chemical fertilizers), which had the lowest accumulation of nitrate, application of growth-promoting bacteria and mycorrhizal fungi in combination with nitrogen fertilizer caused lower nitrate accumulation than chemical fertilizers treatments. So, the use of combined and pure bacteria treatments and mycorrhizal fungus treatment can be used to improve the growth, quality and antioxidant properties and increase the concentration of nutrients and also reducing nitrate accumulation in lettuce.
Growing vegetables
Moslem Ghoreyshi; Fatemeh Nekounam; Taher Barzegar; Jafar Nikbakht
Abstract
Introduction
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 ...
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Introduction
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 is influenced by reduction in turgor that results in decreased nutrient acquisition from dry soil. When water supply is limited, plant growth and yield is reduced and plant structure is modified by decreasing in leaf size. The effect of deficit irrigation on fruit yield and quality has been reported by numerous researchers with different results. In melon, deficit irrigation reduced marketable fruit number and yield, average fruit weight, fruit diameter and did not affect rind thickness and seed cavity, but increased total soluble solids content. Although the effects of water stress have been studied on growth and yield of different crops during the last years, recent information on the response of African horned cucumber yield and quality to deficit irrigation remains limited, particularly about the results of restricted water distributions in arid and sub-arid environments. The main goal of this study was to evaluate the effect of controlled deficit irrigation on growth, physiological parameters and yield and fruit quality of African horned cucumber.
Material and Methods
Field experiment was performed based on a completely randomized block design with three irrigation regimes (60, 80 and 100 %ETc), whit three replications at Research Farm of University of Zanjan during the 2019. The African horned cucumber seeds were sown on 1th July 2020 at recommended spacing of 50 cm in row with 120 cm between rows. The irrigation system consisted of one drip line every crop row. The three irrigation levels were calculated based on actual evapotranspiration (ETc): (1) control, irrigated 100% crop water requirement, (2) deficit irrigation 80% ETc and (3) deficit irrigation 60% ETc. The Water requirement of the plant for control treatment was estimated using long-term average daily data of meteorological parameters recorded at Zanjan Meteorological Station and following relation. Before starting the differential irrigation at five-leaf stage, all treatments were supplied with similar amount of water to maximize stands and uniform crop establishment. During plant growth, the relative water content, proline content, electrolyte leakage, chlorophyll and carotenoids, P and K contents were measured. After fruit harvest, vine length of each plant, leaf dry weight and stem diameter were measured. The fruits were harvested when color changed from green to yellow. Fruit weight, fruit number per plant and fruit yield per plant was measured. Immediately after harvest, fruit firmness, total soluble solid, total phenols content, antioxidant capacity and vitamin C were determined.
Results and Discussion
As the results showed water deficit stress significantly reduced plant length, chlorophyll content, and increased carotenoids content. Based on the findings, deficit irrigation caused a significant reduction in leaf relative water content. According to the results, phosphorus and potassium contents in African horned cucumber leaves decreased with deficit irrigation treatments. The highest P and K contents were found under irrigation 100 %ETc treatment. Drought stress and associated reduction in soil moisture can decrease plant nutrient uptake by reducing nutrient supply through mineralization. The proline content increased with the deficit irrigation treatments; in particular with sever deficit irrigation (60 %ETc). Mean comparisons of data showed that deficit irrigation led to a significant increase in electrolyte leakage compared to control.
Water deficit stress caused significant reductions in yield. The highest fruit number per plant and yield were obtained under irrigation 100% ETc. The average fruit weigh significantly increased in response to increase water deficit stress. Deficit irrigation treatments significantly decreased vitamin C and fruit firmness. Significant differences among irrigation treatments were observed for total phenols and total soluble solid contents. The phenols and total soluble solid contents increased with the decrease of irrigation water applied. Antioxidant capacity was affected significantly by the irrigation treatments, and water deficit stress increased antioxidant capacity, which no significant difference was observed between irrigation 100 and 80 %ETc.
Conclusion
Water deficit has been shown to adversely affect plant growth, fruit yield, and leaf water status of African horned cucumber, but led to increase the TSS and antioxidant capacity. According to the results, fruit yield reduced 13.9 % under irrigation 80% ETc compared to irrigation 100% ETc, However, water consumption was saved by 20% and improved fruit weight and fruit quality with increasing soluble solids and antioxidant capacity.
Growing vegetables
Reza Najafi; Taher Barzegar
Abstract
Introduction
Cauliflower is one of the world’s most important vegetable crops. The edible head of the cauliflower is called curd, which is composed of many florets formed of aborted floral meristems. Curd has various components with high nutritional value including glucosinolates, vitamin ...
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Introduction
Cauliflower is one of the world’s most important vegetable crops. The edible head of the cauliflower is called curd, which is composed of many florets formed of aborted floral meristems. Curd has various components with high nutritional value including glucosinolates, vitamin A and C, phenolic compounds, and carotenoids, which exert beneficial effects on our health. Calcium is an essential macronutrient that plays a vital role in maintains cell wall stability, integrity and determining the fruit quality. Several researches have explored the effects of calcium salts on plant growth and quality in many horticulture crops. Various studies indicate that Ca2+ reduced peroxidation of lipid, increased activity of antioxidant enzyme and improve osmotic adjustment of cell membranes. Plant roots absorb calcium from the soil solution in the form of Ca2+ ions. The mobility of calcium in plant is low, and the root uptake from fertilized soils is poorly effective in increasing the calcium content in leaves and fruits. Deficiency of Ca will appear in younger leaves and in fruits, due to its low rate of transpiration. Thence, it is necessary to have a constant supply of calcium to continue growing. The direct application of liquid source of calcium on leaves and fruits may offer an alternative solution. The efficiency of foliar application with Ca depends on the source of Ca and applied dosage. To our knowledge, however, little information is available regarding the effect of different calcium sources on cauliflower. Thus, the aim of this study was to investigate the effect of foliar spray of calcium sources on quality and antioxidant properties of cauliflower cv. Romansco.
Material and Methods
In order to evaluate the effect of different sources of calcium on antioxidant properties and quality of cauliflower cv. Romansco, the field experiment was carried out as a randomized complete block design with three replication during 2018 at Research farm of faculty of Agriculture, at the University of Zanjan, Iran. Cauliflower plants (cv. Romanesco) were cultivated by applying conventional farming practice for growing in open air conditions. Different calcium sources including calcium nitrate (Ca(NO3)2, 0.5, 1 and 1.5 %), calcium chloride (CaCl2, 0.3, 0.6 and 0.9 %) and calcium lactate ( C6H10CaO6, 0.5, 1 and 1.5 g L-1) were sprayed in vegetative stage and 10 days after curd formation for 2 times onto the leaves and curd until runoff using a mechanical mist sprayer. Distilled water was used as a control. Potassium, phosphorus, total soluble content, titratable acidity, ascorbic acid content, total phenols and flavonoids, free radical scavenging activity (DPPH) were measured. Statistical analyses were performed with SPSS software package v. for Windows, and means comparison were separated by Duncan’s multiple range tests at p < 0.05.
Results and Discussion
The results showed that foliar spray of different Ca sources significantly increased K content and decreased P content. The highest amount of K (5.6 µg mg-1DW) was achieved in CaCl 0.9% treatment. The highest value of flavonoids (0.86 and 0.85 %) was found in plants treated with CaL 1.5 g L-1 and CaCl 0.9%, respectively. In this study, also it was found that foliar spray of CaN 1.5% and CaCl 0.9% increased respectively 49.3 and 40.4% vitamin C content compared to control plants. Ca application with increasing phenolic compound and vitamin C contents, improved antioxidant capacity and the maximum antioxidant capacity (26.19%) was found in CaL 1.5 g L-1 and CaN 1.5% treatments. Application of Ca sources increased TA and TSS content. The highest TSS content (12.5 and 13.3 ºB) was achievd in CaCl 0.9% and CaL 1.5 g L-1 and the maximum TA (28.8%) was found in plant treated with CaCl 0.9%. In this regard, foliar application of high level of calcium sources was more efficient than of lower levels on cauliflower quality. Therefore, the leaf application of calcium can be effective in improving the quality of vegetables, especially cauliflower.
Conclusion
Study results suggest that spraying different Ca source improved quality and antioxidant properties of cauliflower cv. Romanesco, so that with the application of Ca salts increase K, vitamin C, phenol and flavonoids contents. Among the calcium treatments used, higher levels of all three salts of CaCl, CaN and CaL had the most influence, so these calcium treatments are recommended to improve the quality and antioxidant properties of Romanesco cultivar.
Reza Najafi; Taher Barzegar; Farhang Razavi; Zahra Ghahremani
Abstract
Introduction: Eggplant (Solanum melongena L.) is an important non-climacteric fruit grown in tropical and subtropical regions. The total production in Iran and world for eggplants in 2018 were estimated 54077210 and 666838 tons, respectively, and Iran ranked fifth in the production of this product. The ...
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Introduction: Eggplant (Solanum melongena L.) is an important non-climacteric fruit grown in tropical and subtropical regions. The total production in Iran and world for eggplants in 2018 were estimated 54077210 and 666838 tons, respectively, and Iran ranked fifth in the production of this product. The health-promoting attributes of eggplant are derived from the phytochemicals with good source of antioxidants (anthocyanin and phenolic acids), dietary fiber and vitamins. Fruit deterioration during long term storage is associated with appearance quality reduction, calyx discoloration, softening and pulp browning caused by the oxidation of phenolic compounds. Hydrogen Sulfide (H2S) is a flammable and colorless gas, that similar to carbon monoxide and nitric oxide, is known as third leading signaling molecule. It has been reported that H2S play an imperative role in the postharvest physiology and chilling injury of various fruits and vegetables. In recent years, exogenous phenylalanine (PA) application has been employed as a beneficial procedure for enhancing quality in fruits and vegetables by promoting higher phenols and flavonoids accumulation arising from higher PAL enzyme activity and proline accumulation exhibiting higher ROS scavenging capacity. Thus, the aim of this study was to investigate the postharvest application of H2S and PA on quality and postharvest storage of eggplant fruit during storage at 7 °C for 21 days. Material and Methods: Eggplant fruits (Solanum melongena cv. Hadrian) were harvested at commercially maturity stage in Jun 2019 from a greenhouse in Hashtgerd city, Iran. Fruit selected for uniform size, shape, and color, and immediately transported to the laboratory. They were divided into seven parts for the following treatments: control (0), hydrogen Sulfide (H2S) at 0.1, 0.2 or 0.3 mM and phenylalanine (PA) at 2.5, 5 or 7.5 mM. Each treatment was done in three replicates, consists of 24 fruits from each replicate, and then randomly divided into four groups include six fruits. One group was analyzed 24 hrs. after harvesting and another groups stored at 7 ± 1 °C and 85% RH for 21 days. At 7-day intervals, one group was taken at random and transferred for one day at 20 °C (shelf-life), and subjected to physicochemical analysis. For H2S fumigation, fruit was placed at the bottom of a sealed 15 L container with different aqueous sodium hydrosulfide (NaHS) solution concentrations for 10 min, and for PA treatments, the fruits were immersed in 10 L of fresh phenylalanine solution for 10 min and in distilled water as a control. The fruits were allowed to completely dry at room temperature before storage. Results and Discussion: The results showed that fruits treated by PA and H2S exhibited higher fruit firmness, chlorophyll, anthocyanin, total soluble solids (TSS), vitamin C, pH and titratable acidity (TA) accompanied by lower weight loss and chilling indices during storage at 7 ºC for 21 days. In control eggplant fruits, fruit firmness (24.2%), chlorophyll (45.8%), vitamin C (34.1 %), anthocyanin content (66.2 %) and TA (44.8) decreased, and weight loss (7.5 %), TSS (8.2%) and chilling indices (4.5 %) increased during 21 storage time. The maximum fruit firmness (1.37 and 1.34 kg cm-2), anthocyanin content (5.02 and 4.2 mg L-1) and TA (18.67 and 1.37 %), and the lowest weight loss (3.67 and 3.7 %) and chilling index (1.6 and 1.3 %) was found in fruits treated with H2S at 3 mM and PA at 7.5 mM during storage at 7 °C for 21 days, respectively. It has been reported that texture correlates with firmness and higher firmness is a characteristic indicator of good texture during postharvest storage of fresh products. Soluble solid contents, titratable acidity (TA) and sugars have been known as important attributes contributing in overall sensory quality of fruits and vegetables. Development of the chilling injury disorder significantly reduces quality of fruits and vegetables due to diminished consumer’s acceptance. So, start of chilling injury symptoms eventually becomes economically critical postharvest constraint that defines the storage life potential of the products. Decline chilling injury in responses to H2S and PA treatments may resulted from higher ROS scavenging enzymes SOD, CAT, APX and POD activity and proline, phenols and flavonoids accumulation giving rise to conferring chilling tolerance. Conclusion: According to results, PA at 7.5 mM and H2S at 3 mM had the highest positive effect on maintain firmness and fruit quality and reducing weight loss and chilling, therefor postharvest treatment of PA and H2S can be proposed to improve fruit quality and postharvest life during storage period.
Mahsa Fateh; Taher Barzegar; Farhang Razavi
Abstract
Introduction: Sweet pepper (Capsicum annuum L.) is a worldwide used vegetable, which is an excellent source of ascorbic acid and has high antioxidant capacity against oxidative damage caused by free radicals. Ascorbic acid (AsA) is a water-soluble vitamin that plays a key physiological role in ...
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Introduction: Sweet pepper (Capsicum annuum L.) is a worldwide used vegetable, which is an excellent source of ascorbic acid and has high antioxidant capacity against oxidative damage caused by free radicals. Ascorbic acid (AsA) is a water-soluble vitamin that plays a key physiological role in scavenging reactive oxygen species (ROS), and enzyme cofactor. In recent years, the application of exogenous AsA has received much attention for use as a biologically safe compound for postharvest quality maintenance of many horticulture crops. Calcium is an essential micronutrient that plays a vital role in maintains cell wall stability, integrity and determining the fruit quality. To our knowledge, however, little information is available regarding the effect of ascorbic acid and calcium lactate on pepper fruits. Thus, the aim of this study was to investigate the foliar application of ascorbic acid and calcium lactate on growth, yield and fruit quality of sweet peppers.
Materials and Methods: To study the effect of foliar application of calcium lactate (Ca) and Ascorbic acid (AsA) on growth, yield and fruit quality of sweet pepper, the field experiment was carried out from June to September 2016 at Research farm of faculty of Agriculture, at the University of Zanjan, Iran. Pepper plants (cv. California Wonder) were cultivated by applying conventional farming practice for growing in open air conditions. 210 plants (30 plants for each treatment) were selected for uniform size and fruit load, and were sprayed three times (0, 15, 30 days after full bloom) with an aqueous solution containing different concentrations of Ca (0, 0.5, 1 and 1.5 g L-1) and AsA (100, 200 and 300 mg L-1). Each treatment was carried out with three replicates. Pepper fruit were harvested at commercial maturity stage, and transferred to the laboratory on the same day. Leaf area was recorded whit measurement leaf area (DELTA-T DEVICEC LTD, ENGLAND). After fruit harvested, plant length was measured. Fruit was weighted after harvest to determine mean fruit weight. The fruit number per plant and fruit yield per plant was measured to determine of total yield. The total yield expressed in kg ha–1. Flesh firmness was determined with penetrometer (model Mc Cormic FT 32), using an 8 mm penetrating tip. Results were expressed in kg cm-2. The pH values of solutions were monitored with pH meter. TSS was measured in the extract obtained from three fruit of each replicate with a digital refractometer Atago PR-101 (Atago Co., Ltd., Tokyo, Japan) at 20◦C. Total ascorbic acid content was expressed as mg per 100 g of juice. Antioxidant activity was measured using the free radical scavenging activity (DPPH) and calculated according to the following formula: RSA%= 100(Ac-As)/Ac. Statistical analyses were performed with SPSS software package v. 20.0 for Windows, and means comparison were separated by Duncan’s multiple range tests at p < 0.05.
Results and Discussion: The results showed that foliar application of AsA had significant effects on growth and fruit yield. The highest fruit yield (897.1 g plant-1) was achieved at 300 mg L-1 AsA that had no significant difference with 200 mg L-1 AsA. Foliar application of AsA markedly increased vitamin C content, and also the highest value of total soluble solid (5.7 °B) was recorded from 300 mg L-1 AsA. Ca had no significant effects on growth and fruit yield but significantly improved fruit firmness. The highest fruit firmness (2.13 and 2.16 kg cm-1) was obtained from 1 and 1.5 g L-1 Ca. The maximum antioxidant activity was achieved with application of 300 mg L-1 AsA and 1.5 g L-1 Ca. The fresh sweet peppers were an important source of ascorbic acid for human consumption. AsA significantly increased the amount of vitamin C in the plum and sweet pepper fruits. Foliar treatment of Ca increased vitamin C content. Increasing vitamin C content in fruits after treatment with Ca could be related to inhibiting action of calcium on the activities of ascorbic acid oxidase that use ascorbate as a substrate. The results indicated that treatment of Ca produced fruits with higher firmness compared to control and other treatments. Firmness and resistance to softening can be increased by the addition of Ca, due to interaction of calcium with pectate acid in the cell wall to form calcium pectate and retarding polygalacturonase activity. Differences in the percentage of TSS content at the time of harvest indicated the AsA and Ca effects on carbohydrate accumulation in fruits, which had different potential on respiration rates and consequently storability of plants. The exogenous application of AsA and Ca in sweet pepper plants indicated that treatments had significant effects on ascorbic acid content of sweet peppers. The antioxidant activity has positive correlation with total phenolic content, flavonoids and content of ascorbic acid.
Conclusion: The results of our research indicated that per-harvest foliar application of AsA increased plant growth, fruit number and weight. Also, AsA and Ca treatments improved fruit quality attributes including vitamin C, fruit firmness, TSS and antioxidant activity. These results suggest that AsA and Ca treatments, especially AsA 300 mg L-1 and Ca 1.5 g L-1, may be proposed to improve fruit quality.
Reihane Mesgari; Taher Barzegar; Zahra Ghahremani
Abstract
Introduction: Cucumber is one of the most important vegetable crops for the local consumption and exportation. The use of grafted vegetable seedlings has been popular in many countries during recent years. Growing fruit-bearing vegetables, chiefly tomato, cucumber and watermelon through grafted seedlings ...
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Introduction: Cucumber is one of the most important vegetable crops for the local consumption and exportation. The use of grafted vegetable seedlings has been popular in many countries during recent years. Growing fruit-bearing vegetables, chiefly tomato, cucumber and watermelon through grafted seedlings become a widespread practice worldwide. Grafting is a valuable technique to avoid soil-borne diseases, provide biotic and abiotic stress tolerance, enhance nutrient uptake, optimize water use, and increase fruit yield and quality. Vegetable grafting is a new topic in Iran and there are a limited number of studies on grafted vegetable production. However, attention to grafting by researchers has recently increased. Suitable rootstocks should be identified and characterized for the effective utilization of grafting. The rootstock's vigorous root system increases the efficiency of water and nutrient absorption, and may also serve as a source of endogenous plant hormones, thus leading to increased growth and yield in addition to disease control. In the present study, we investigated the response of two Cucurbita sp. and an Iranian melon as rootstocks for cucumber.
Materials and methods: In order to study the effect of cucurbit rootstocks and grafting method on growth, yield and fruit quality of cucumber (Cucumis sativus cv. Super Dominus), an experiment was conducted as a factorial design in the base of RCBD with three replications in the greenhouse and research farm, University of Zanjan. Treatments were included three rootstocks (Cucurbita moschata L., Lagenaria siceraria and Cucumis melo L.) and ungrafted plants (control) and two grafting method (hole insertion and splice grafting). Seeds were sown simultaneously in plastic pots. For obtaining the same stem diameter of scion and rootstocks, cucumber seeds were planted four days earlier than rootstocks seeds. The seedlings were grown in an environment-controlled greenhouse with 25/20 day/night temperatures. When seedlings reached the first true leaf stage (diameter of the leaf was about 2 cm) the grafting was performed. After grafting, grafted plants were transferred to a mist chamber for post-graft care (>95% RH, 27-30 °C) for 10 days, after which the relative humidity was reduced gradually for acclimatization. After 20 days of grafting, surviving grafted plants and ungrafted plants were transplanted to the field. Common agricultural practices like fertilizer application, insects and disease control were adopted. Vegetative growth, yield and fruit quality were measured. Data were analyzed using the SAS statistical program (SAS Institute Inc., Cary, NC, USA), and means were compared by Duncan’s multiple range tests at the 5% probability level.
Results and Discussion : The result showed that rootstocks had a significant effect on growth indexes. Cucumber was grafted on cucurbita moschata L. rootstock had the highest stem length and leaf numbers, while, the lowest values of plant height, leaf area, leaf number and yield were recorded with grafted plant on melon rootstock. Fruit numbers were significantly influenced by rootstock. The highest fruit number per plant was observed in cucumber plants that were grafted on cucurbita moschata rootstock. The results of the study showed that cucumber grafting on suitable rootstocks had positive effects on the yield. But rootstock had no significant effects on fruit quality like flesh firmness and total soluble solid. The Soluble solid content of fruit was reported to decrease in tomato, cucumber and eggplant due to grafting. chlorophyll content of leaf showed significantly different between grafted and non-grafted plants. The highest amount of leaf area was obtained from non-grafted plants. Grafting methods had no significant difference in growth, yield and fruit quality. Nitrogen and potassium leaf contents of grafted cucumber and ungrafted plants had no significant difference. The interaction between rootstocks and grafting method had no significant effect on yield and the other growth indexes.
Conclusion: Our findings showed that vegetative growth and yield of cucumber were affected by grafting. On the basis of these results, Cucurbita moschata rootstock had the highest effect on growth and yield of cucumber. It may also be concluded that the grafting method had relatively same growth response. Although the cost of a grafted seedling is surely one of the main concerns of growers, especially since grafted seedling costs from three to five times more than non-grafted seedling. However, investigation proved that, on-farm grafted cucumber transplant production can be successful and the results indicate that grafting of cucumber onto cucurbit rootstocks can increase on-farm net returns due to improve growth and yield.
