Pomology
afsaneh Salehi; Fatemeh Nekounam; Farhang Razavi
Abstract
Introduction
Apple (Malus domestica) belongs to the Rosacea family and is one of the most important fruit trees in temperate regions. Apple fruit is a rich source of vitamins, sugars, organic acids, minerals, fibers, and bioactive compounds and is widely cultivated due to its pleasant taste, aroma, and ...
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Introduction
Apple (Malus domestica) belongs to the Rosacea family and is one of the most important fruit trees in temperate regions. Apple fruit is a rich source of vitamins, sugars, organic acids, minerals, fibers, and bioactive compounds and is widely cultivated due to its pleasant taste, aroma, and texture. Due to the rising need for food and fiber per unit of land area, chemical fertilizers are becoming increasingly popular to increase yields from small plots of land. Chemical fertilizers pose major health risks and harm the environment when they are used in excess. Because of this, research in this area is heavily focused on finding and evaluating the efficiency of new products. One such approach is using biostimulants that can enhance the effectiveness of conventional mineral fertilizers. Plant biostimulants contain some nutrients (marine plant extracts, humic acids, amino acids and other natural products such as saponins and compost teas) that stimulate plant growth, even when administered in small amounts. Foliar application of seaweed extracts at 0.2% recorded maximum no. of fruits/tree, fruit weight, and yield/tree in valencia orange.
Materials and methods
In order to investigate the effect of biofertilizers on growth, yield and leaf nutrient contents of apple under climatic conditions of Zanjan, the experiment was carried out in a completely randomized block design with three replicates in 2023. Different concentration of seaweed (Alg; 0.075 and 0.15%), amino acid (GF Amino; 0.1 and 0.2%), humic acid (HA; 0.3%), commercial fertilizer Homarang, (Homa fert; 0.5%), combined chemical fertilizer (nitrogen, zinc and boron (Combinate fert; 1% urea, 0.3% zinc chelate and 0.1% boric acid)) and distilled water as a control were sprayed on the trees at 40 days after full bloom stage until runoff using a mechanical mist sprayer, and repeated three times with an 30 days interval until the physiological ripening of fruits. The experiment was carried out on 10-year-old Red Delicious apple trees grafted on M9 rootstocks. Shoot length, chlorophyll index, fruit drop percentage, yield efficiency, leaf area, leaf dry matter, leaf macro and micro nutrient were measured. The analysis of variance (ANOVA) and least significant difference test (P≤ 0.05) used to compare means within each sampling date. The Statistical analysis and standard error calculation were carried out using SAS software (V. 9.3).
Results and Discussion
The results showed that the foliar application of bio and chemical fertilizers significantly increased growth and fruit yield. So that, the highest increase in shoot length (39%) and leaf area (74.30%) compared to the control was obtained with application of seaweed 0.075%. Also, seaweed 0.15%, amino acid 0.2%, humic acid and amino acid 0.1% caused a significant increase in leaf area (42.02, 35.57, 22.27 and 16.20%, respectively) compared to the control. Foliar spray of seaweed, amino acid and chemical fertilizer increased chlorophyll index. The highest increase in chlorophyll index (50%) compared to the control was obtained with application of combined chemical fertilizer at 130 days after full bloom. These results are in agreement with the outcomes of other experiments conducted with seaweed on apple and on other crops such as grapevine. Therefore, this represents a further evidence of a possible role of seaweed extracts in the reduction of chlorophyll degradation and in delaying leaf senescence. The highest amount of nitrogen (1.66%), potassium (1.03%) zinc (150 mg g-1DW) and boron (82.5 mg g-1DW) and the lowest amount of phosphorus (0.44%) were obtained with application of combined chemical fertilizer. The highest value of iron was observed in leaf of trees treated with seaweed 0.15%, humic acid and commercial biofertilizer. Based on the results, it was observed that the amino acid, seaweed and combined chemical fertilizer have the greatest effect in reducing fruit drop (36.97, 33.37, 29.07%, respectively) compared to control) and increasing yield efficiency (respectively 2.75, 2.73 and 2.8 compared to control with 0.22 fruits No. cm-2 SCSA). These results partially are in agreement with another research performed on apple, where the use of a similar seaweed extract (Ascophyllum nodosum) was found able to induce a higher final yield. The hormonal components found in the extracts, particularly cytokinins, are assumed to be responsible for the increased yield in plants treated with seaweed. Previous studies mentioned that the application of biological fertilizers alone or in combination with the mineral fertilizers had positive influences on the leaf plate area, mean fruit weight and fruit chemical composition.
Conclusions
According to the results of this research, the use of biofertilizers, especially seaweed (0.15%) and amino acid (0.1%), are suitable and nature-friendly substitutes for chemical fertilizers and can play a significant role in increasing growth indices and yield of apples.
Postharvest physiology
Mahshid Ghafouri; Farhang Razavi; Masud Arghavani; Ebrahim Abedi Gheshlaghi
Abstract
Introduction Nowadays, the application of chemical compounds is limited due to their harmful effects on human and the environment health. The benefits of seaweeds as sources of organic matter and fertilizer nutrients have been known to agriculture for centuries, especially in coastal areas extracts ...
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Introduction Nowadays, the application of chemical compounds is limited due to their harmful effects on human and the environment health. The benefits of seaweeds as sources of organic matter and fertilizer nutrients have been known to agriculture for centuries, especially in coastal areas extracts of these seaweeds have been used for decades as foliar- and soil-applied treatments in crop production systems due to the presence of a number of plant growth-stimulating compounds. Unlike chemical fertilizers, extracts derived from seaweeds are biodegradable, non-toxic and non-hazardous to humans, animals and birds. Therefore, it is required to find a safe compound that is utilized in the postharvest technology of fruit and vegetables. Pre-harvest application of nutrient solutions such as seaweed increases the quality and quantity of crop and also enhance their storage life and marketability. Various researchers reported that aqueous extracts of seaweed increased the yield and quality of tangerine and orange, strawberry, grape, apple, and watermelon fruit. Thus, the aim of the current study was to investigate the effect of pre-harvest foliar application of Seaweed extract on quality and quantity values, antioxidant properties, and storage life of kiwifruits.Material and Methods This experiment was carried out on 10-year-old kiwifruit vines, in a commercial orchard located in Gilan Province. Vines were selected with uniform size in terms of growth, yield and fruit load, then sprayed with seaweed extract at four levels of 0, 1, 2 and 3 g.l-1 as a foliar spray and control vines only received water. Foliar spraying was performed in three stages, (110, 125 and 140 days after full bloom stage) and Tween 20 was used as a surfactant. This experiment was designed as factorial based on randomized complete block design with three replications. The fruits were harvested in November with soluble solids content (TSS) of 6.5-6.2% and then transferred to the post-harvest physiology laboratory of the University of Zanjan. The treated fruits were stored for 90 days at 1 ° C with 90% RH. Sampling was done at harvest time and after 30, 60 and 90 days of storage and some quantity and quality traits such as weight loss, tissue firmness, TSS, ascorbic acid, total phenol and flavonoids, antioxidant capacity and the activity of superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL) enzymes were evaluated.Results and Discussion The ANOVA results showed that seaweed extract, storage time, and interaction of seaweed extract × storage time had a significant effect (p≤0.01) on evaluated traits. All treatments maintained the antioxidant capacity, total phenol and flavonoids content and PAL activity at a higher level compared with control. The amount of fruit tissue firmness, TA and ascorbic acid decreased by increasing the storage time, and at the third month of storage, the lowest amount was observed in the control fruit. Also, comparing the interaction of the mean of treatments and storage time showed that pH, weight loss, TA, TSS, antioxidant capacity, total phenol, flavonoids and PAL enzyme activity increased by increasing the storage time. At the end of the storage time, the highest level of TSS, weight loss and pH were observed in the control fruit. The lowest antioxidant capacity (48.14 %) was observed in the control treatment at harvest time and the highest antioxidant capacity was observed in 3 levels of brown algae extract treatment at the end of storage period. Comparison of means showed that at the first 30 days of storage, the highest PAL enzyme activity was observed in the treatment of 3 g / l of brown algae. PAL enzyme activity significantly increased after the experiment. At the end of storage period, the lowest PAL enzyme activity was observed in control fruit. Treatment of 3 g / l brown algae had higher PAL activity. PAL, as a key enzyme in phenylpropanoid metabolism, catalyzes the conversion of phenylalanine to trans-cinnamic acid, which is the first step in the biosynthesis of phenylpropanoids and leads to the production of secondary metabolites such as lignin, phytolaxoids, and flavonoids. The direct and positive relationship of this enzyme with the synthesis of phenols and flavonoids has been discovered in the fruits of blood orange, strawberry and blueberry. The results of the comparison of the mean showed that the total phenol and flavonoids increased by increasing the storage time. The lowest phenol (23 mg GAE.100 g-1 FW) was observed in control fruit at harvest and the highest (8.88 mg GAE.100 g-1 FW) content of total phenol was observed in 3 levels of brown algae extract at the third month of storage. Plants release phenolic compounds in response to some messenger compounds that play an important defense role. Studies show that there is a positive relationship between total phenol content and their antioxidant activity. Flavonoids are also polyphenolic compounds and are the most important secondary compounds of plants. Under oxidative stress, in plants, the activity of propanoid pathway increases, especially the pathway of flavonoids biosynthesis. Flavonoid compounds are abundant in plants and show antioxidant activity. Seaweed extract enhances the antioxidant capacity of the fruit and thereby inhibits oxygen-free radicals Treatment of 3 g/l seaweed extract had the best effect among the treatments applied in maintaining firmness, fruit weight loss, TA, antioxidant capacity, total phenol and flavonoids and PAL enzyme activity. All three levels of seaweed extract increased the amount of total phenol, flavonoids and antioxidant capacity all over the storage time, but no significant difference was observed among the treatments levels. Based on the results, the application of 3 g/l seaweed extract effectively increased the antioxidant capacity and PAL enzyme activity during 90 days of storage time. As a result, seaweed extract treatment had positive effects on maintaining the quality and increasing the shelf life of kiwifruit during 90 days of storage.ConclusionSeaweed extract is one of the natural compounds and compatible with human health and nature has medicinal and nutritional value that can increase the shelf life and maintain fruit quality in the postharvest period. In summary, foliar application of seaweed extract has a significant effect on fruit firmness, total soluble solids, total acid, vitamin C, phenol and total flavonoids, total antioxidant activity and the enzyme phenylalanine ammonialyase. The appropriate treatment for kiwifruit cultivar ‘Hayward’ is introduced. Among the applied treatments, 3 g/l of seaweed extract had the best effect on firmness (40.40%), fruit weight loss percentage (41.87%), titratable acid (25.37%), vitamin C (33.26%), antioxidant capacity (26.70%), total phenol (81.17%), total flavonoids (103.67%) and PAL enzyme activity (153.75%) compared to the control in 90 days of storage.
Postharvest physiology
Fahime Nasr; Vali Rabiei; Farhang Razavi; Gholamreza Gohari
Abstract
Introduction
Persimmon (Diospyros kaki Thunb.) is an important fruit that is consumed due to high nutritional, desirable taste and flavor. Unfortunately, most persimmon fruit producers do not use the suitable technology to preserve the fruit quality, consequently, marketing their product at lower ...
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Introduction
Persimmon (Diospyros kaki Thunb.) is an important fruit that is consumed due to high nutritional, desirable taste and flavor. Unfortunately, most persimmon fruit producers do not use the suitable technology to preserve the fruit quality, consequently, marketing their product at lower prices. The fruit of Karaj cultivar is one of the best and highest quality cultivars in Iran but this fruit is sensitive to chilling injury and shows drastic softening and reduced nutritional value as chilling damage. Appliacation of effective treatments for reducing chilling symptoms and preserve quality can lead to the increase of shelf life in this fruit. Ascorbic acid is an important nutrient that it is required for the functioning of several enzymes and is important for immune system function. It also functions as an antioxidant. Recently this treatment has gained much attention for use as an environmentally friendly technology for the maintenance of postharvest quality of many horticultural crops. In this regard, the aim of the present study was to assess the effect of ascorbic acid and storage time on the postharvest life of persimmon fruit.
Materials and Methods
Persimmon fruit (cv.‘Karaj’) was first harvested at physiological maturity stage from a commercial orchard in Karaj city, then immediately transported to the postharvest laboratory at University of Zanjan. Fruit selected for uniformity of size, shape, color and free from disease or mechanical damage. The treatments included ascorbic acid at three levels (15, 30 and distilled water as a control mmol.L-1) and storage time at three levels (15, 30 and 45 day). Fruit was dipped in solution of Ascorbic acid 15 and 30 mmol.L-1 and distilled water (control) for 10 min. After treatment, the fruits were stored at +4°C and 85-90% relative humidity for 45 days. Fruits were sampled during storage after (15, 30 and 45 days) and 24 hours maintaining at room temperature and fruit firmness, weight loss, TSS, TA, vitamin C, total flavonoids, total phenol, soluble tannins, total carotenoids, antioxidant capacity and MDA were measured at the end of each period. Persimmon fruit samples were weighed before and after the storage to calculate weight loss (%) during storage by using the formula of [(weight of fruits before the storage − weight of fruits after the storage)/weight of fruits before storage] × 100. Fruit firmness was determined using OSK 1618 penetrometer equipped with an 8 mm tip at 3 equatorial points, and the results were expressed as kg/cm2, Soluble tannin was measured by using the method of Tiara (1996). Total carotenoid was measured based on wang et al (2006), Total soluble solid (TSS) was measured by using refractometer, Ascorbic acid content was determined by using the method of Jalilimarandi (2000) and Antioxidant activity was evaluated by measuring the scavenging activity of the examined extracts on the 2,2-diphenylhydrazil (DPPH) radical as described by Dehghan and Khoshkam (2012). Statistical analysis was performed using SAS V9 software and the treatment means were separated by Duncan’s multiple range tests.
Results and Discussion
Results showed that all treatments showed significant effect on evaluated traits. All treatments preserved vitamin C and antioxidant activity of fruit compared with control. Ascorbic acid 30 mmol.L-1 significantly preserved firmness, soluble tannin, total phenol, flavonoid, antioxidant capacity. Based on current results that ascorbic acid 15 and 30 mmol.L-1 treatments were the most effective in delaying decrease weight loss by reduced metabolic activity, delayed senescence, and maintained better cellular integrity thereby worked in an integrated manner to reduce fresh weight loss of persimmon fruit. Increasing Ascorbic acid suppressed oxidative damage possibly by quenching hydrogen peroxide and superoxide anion. Therefore, positively correlated with higher membrane integrity and less MDA of persimmon fruit. Ascorbic acid is not only an important nutraceutical compound but also a critical antioxidant that positively eliminates certain reactive oxygen species and preserve antioxidant compounds such as phenol, flavonoid, carotenoid and vitamin C in post-harvest. Ascorbic acid 15 and 30 mmol.L-1 treatments used in this experiment had no effect in changes TSS and total carotenoid. So ascorbic acid can improve effectively the quality and increase shelf life of fresh persimmon fruit in post-harvest.
Conclusion
In conclusion, our research indicates that ascorbic acid could prolong postharvest life of persimmon fruit by maintaining fruit quality attributes. Ascorbic acid treatment significantly is effective in preserving, firmness antioxidant compounds, quality properties and increasing the storage time of persimmon fruit of Karaj cultivar without harmful for human health. Hence, ascorbic acid treatment is a safe and applicable method of increasing the shelf life and preserving the quality in persimmon during cold storage.
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.
Mohsen Moradi; Farhang Razavi; Vali Rabiei; Morteza Soleimani Aghdam; Leila Salehi
Abstract
Introduction: In recent years, γ-aminobutyric acid (GABA), a non-proteinogenic four-carbon signaling amino acid, has been employed as a safe strategy for attenuating chilling injury and fungal decay, delaying senescence and keeping sensory and nutritional quality of fruits and vegetables during postharvest ...
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Introduction: In recent years, γ-aminobutyric acid (GABA), a non-proteinogenic four-carbon signaling amino acid, has been employed as a safe strategy for attenuating chilling injury and fungal decay, delaying senescence and keeping sensory and nutritional quality of fruits and vegetables during postharvest life. In addition to applying GABA as exogenous safe procedure, heightening cellular GABA shunt pathway activity also is pivotal for attenuating chilling injury and fungal decay, delaying senescence and keeping sensory and nutritional quality of fruits and vegetables during postharvest life. Low temperature storage is widely employed for prolonging postharvest life of fruits and vegetables accompanying by keeping sensory and nutritional quality. Tomato is one of the most important horticultural crops, which exhibits higher benefits for human health but being endemic to subtropical climates, they are very vulnerable to chilling injury. Cold storage application is normally employed as a regular low-cost real postharvest technology. Owing to its great socio-economic significance, great efforts have been done by researchers to attenuating chilling injury in tomato fruits during low temperature storage employing safe strategies such as melatonin, brassinosteroids, salicylic acid, nitric oxide, and gibberellic acid. Attenuating chilling injury in tomato fruits by postharvest treatments may attribute to keeping safe membrane integrity representing by lower electrolyte leakage and malondialdehyde (MDA) accumulation occurring by eliciting endogenous polyamines, proline and nitric oxide accumulation by activating CBF1 signaling pathway, hampering phospholipase D (PLD) and lipoxygenase (LOX) enzymes activity, activating reactive oxygen species (ROS) scavenging enzymes activity resulting in higher ascorbic acid and glutathione accumulation, maintaining endogenous GA3 homeostasis occurring by higher CBF1 signaling pathway concurrent with higher endogenous salicylic acid accumulation, which not only are pivotal for conferring chilling tolerance in tomato fruits but also are crucial for preserving sensory and nutritional quality.
Material and Methods: Tomato fruits (Solanum lycopersicum cv. Izmir) were picked at the mature green stage in Zanjan Province, Iran, and transported to the fruit analysis laboratory at Zanjan University. In the laboratory, the fruit was screened for uniform size, maturity, and absence of mechanical damage. Fruits (1440) were divided into four groups, each consisting of 360 fruits. The experiment was done in triplicate in which each replicate consisted of 120 fruits. The exogenous GABA applying was done by immersing of fruits in GABA at 0, 0.1, 1, and 5 mM for 15 min at 20 ˚C. Then, fruits were air dried at room temperature and stored at 4 ± 0.5 ºC (85–90 % RH) for 28 days. After assessment of chilling injury every 7 days during storage at 4 ˚C followed by shelf life at 25 ºC for 3 days, biochemical analyses were performed.
Results and Discussion: In recent experiment, we showed that the exogenous GABA applying, especially at 5 mM, is beneficial for attenuating chilling injury in tomato fruits during storage at 4 ºC for 28 days which was associated with higher membrane integrity representing by lower electrolyte leakage and malondialdehyde (MDA) accumulation. Keeping safe membrane integrity in tomato fruits in response to exogenous GABA applying may ascribe to triggering reactive oxygen species (ROS) scavenging catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) enzymes activity giving rise to higher endogenous ascorbic acid accumulation concomitant with promoting phenylpropanoid pathway activity representing by higher phenylalanine ammonia lyase (PAL) enzyme activity giving rise to higher phenols and flavonoids accumulation and superior DPPH scavenging capacity.
Conclusion: Therefore, exogenous application of GABA not only is proficient for attenuating chilling injury but also is beneficial for preserving nutritional quality of tomato fruits during storage at 4 ºC for 28 days.
Mohsen Mozaffari; Farhang Razavi; Vali Rabiei; Azizollah Kheiry; Akbar Hassani
Abstract
Introduction: Demand for healthy and high-quality fruits has increased in the markets, and compositions such as vitamins, sugars, and anti-oxidant properties of fruits have attracted many consumers. Grapes contain phenols, flavonoids, anthocyanins, tannins and vitamins with high antioxidant properties. ...
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Introduction: Demand for healthy and high-quality fruits has increased in the markets, and compositions such as vitamins, sugars, and anti-oxidant properties of fruits have attracted many consumers. Grapes contain phenols, flavonoids, anthocyanins, tannins and vitamins with high antioxidant properties. Antioxidants support biological systems such as proteins, amino acids, lipids, and DNA against oxidative damage produced by active oxygen species of ROS, resulting in reduction of cell damage and death, cardiovascular disease and cancers in the human body. Selenium is essential for humans and animals and should be fed through a diet, for this reason, FAO recommends entering selenium to agricultural products (especially fruits and vegetables). In recent years, selenium has been recognized as a useful element for plants that have been toxic at high concentrations but at desirable concentrations, it has positive antioxidant effects, increases growth and significantly affects seed germination. Selenium protects plants from several abiotic stresses such as heavy metal and arsenic, ultraviolet radiation, and biotic stress such as pathogens and pests. Selenium neutralizes oxidative stress interfering with lipid peroxidation, and accelerates gluthatione peroxidase (GSH-Px) activity, this phenomenon delay plant senescence and diminish postharvest losses. This element increases the yield and improves the quality of the fruits and vegetables. When Camelia oleifera plants were treated with selenium, cellular content of linoleic acid and sterol were elevated but oleic acid content diminished. Selenium treatment had a significant effect on preserving the sensory and the postharvest quality by decreasing respiration rate and ethylene biosynthesis in broccoli by diminishing phenylalanine ammonia-lyase (PAL) activity and ethylene production in lettuce and chicory. Foliar application of peach and pear trees with selenium, decelerated fruit softening rate and elongated shelf-life. Therefore, treatment of agricultural products with the appropriate amount of selenium can have a positive effect on the increase of the quality and enrichment of selenium in fruits and also play an important role in human health.
Materials and Methods: In order to investigate the effect of selenium as foliar application (0, 1, 2 and 3 mg L-1) on quality traits, antioxidant compounds and enrichment of grape cv. Fakhri, an experiment based on randomized complete block design with three replications in a vineyard (Kurdistan Povince, Ghorveh town) was performed. The 15-year-old vines were sprayed with selenium solution plus 0.1% of Twin 20 as surfactant until the leaves were completely wet (for each vine about 0.5 liter) at three stages of berry growth and development: Berry formation, Lag phase and veraison. A 1000 mg L -1 stock solutions (Made by the Belgian company CHEM-Lab, containing selenium ion Se+6) was used to prepare the desired solutions. At commercial fruit maturity stage (20° Brix), samples of fruits and leaves randomly were collected from treated and control vines and were immediately transferred to the postharvest physiology laboratory. Traits such as total chlorophyll, carotenoid, nitrogen, potassium, selenium content of leaves and fruits, and also, total soluble solids, soluble sugars, titrable acidity, acidity (pH), vitamin C, phenol and flavonoids, antioxidant capacity in fruits and the berry weight were evaluated. Data were analyzed using SAS statistical software (SAS V.9.4), and means were compared by Duncan’s multiple range tests at the 5% of probability level.
Results and Discussion: Results showed positive effects of selenium treatment on evaluated traits. As a result, 2 mg L-1 of selenium increased photosynthetic pigments, nitrogen and leaf potassium, soluble solids, soluble sugars, vitamin C, total phenol, antioxidant capacity of fruits in comparison with untreated vines. The highest amount of titrable acidity, total fruit flavonoid and leaf selenium was recorded in vines treated with 3 mg L-1 selenium, whereas, this treatment had less effect on other traits. The highest amount of berry weight was obtained in 1 mg L-1 of selenium. However, none of the selenium treatments had significant effect on the juice acidity (pH). In general, the results showed a positive effect of selenium on improvement of antioxidant properties, quality and enrichment of grape, and 2 mg L-1 selenium with the highest effect on traits was identified as the best treatment. According to other researchers, foliar application of selenium in "Starking Delicious" apple cultivar was effective in enhancement of fruit selenium content and nutritional properties, postponing the flesh firmness decrease, and delaying fruit ripening resulting from less ethylene production, therefore significantly affecting apple fruit quality and storage life.
Akbar Angooti; Jafar Hajilou; Farhang Razavi
Abstract
Introduction: The ability to tolerate cold will not be possible without stopping or inducing sleep, which is one of the important steps in the life cycle of plants in temperate regions. This period is one of the important factors in preventing cold damages in winter and spring in temperate regions. Various ...
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Introduction: The ability to tolerate cold will not be possible without stopping or inducing sleep, which is one of the important steps in the life cycle of plants in temperate regions. This period is one of the important factors in preventing cold damages in winter and spring in temperate regions. Various studies in controlled conditions on plants have shown that in plants, when entering and leaving this period, various changes occur in materials such as proteins, enzymes and hormones. In order to control the harmful effects of active oxygen species, plants have defense mechanisms. Catalase, peroxidase and superoxide dismutase enzymes are a defensive team whose common goal is to defend against the destructive effects of active oxygen species. This study was carried out to determine the chill requirement and its relationship with the changes in the activity of antioxidants enzymes and proline.
Materials and Methods: The experiment was conducted at agricultural Research Station of Khalat-Pooshan and the Laboratory of Flower Biology and Physiology of Fruit Growth in the Department of Horticulture, Faculty of Agriculture, Tabriz University in 2015-2016. Flower buds needed for testing were selected from ‘Siah Shabestar’, Zard Mashhad, Zoodras cultivars and a local genotype of sour cherry. Once a month, enough buds were harvested and until the experiments began, they were kept inside the freezer inside an aluminum foil at -80 ° C. In order to estimate the chill requirement, four replicates (4 geographic directions) from each cultivar and from each replication four branches with the same length and diameter were removed. The amount of chilling accumulation and chilling requirement in each month was calculated according to Utah model. In order to estimate fresh weight, four replicates in each cultivar were selected and in each replication five buds were selected from different parts of the branch. The statistical design used in the determination of the chill requirement was a randomized complete block design. Enzymatic and proline data were analyzed in a completely randomized design as factorial
Conclusions: Chill requirement: Based on the Utah model, the chill requirement of sweet and sour cherry cultivars contains Zard Mashhad, Zoodras and Siah Shabestar were calculated 752, 780, 867 and 961 CU, respectively. There was a significant difference in the activity of superoxide dismutase enzymes between cultivars and different sampling times at 1% probability level. Siah Shabestar cultivars with the highest chill requirement had the lowest SOD enzymatic activity and Zard Mashhad and Zoodras were intermediate cultivars in terms of enzymatic activity. Sour cherries, which had the least chill requirement, showed the highest levels of SOD enzyme activity. This is consistent with the results of some researchers regarding apricot stated that the low chill apricot cultivars had the highest SOD enzymatic activity. The sour cherry had the highest amount of POX enzymatic activity with the least amount of chill requirement, and also Siah Shabestar has the least chill requirement. Like the two previous enzymes, the activity of catalase was highest in sour cherries and the lowest was observed in Siah Shabestar. In terms of the presence of free proline, there was no significant difference between the Zard Mashhad cultivars and Zoodras, while there was a significant difference between these two cultivars and Sour Cherry and Siah Shabestar. Zoodras cultivar has the highest and our cherry has the lowest amount of free proline. Between different cultivars, in terms of fresh weight of buds, there is a significant difference at 1% probability level before and after placement in the growth chamber. The increase in fresh weight of sour cherry and Zard Mashhad, Zoodras and Siah Shabestar cultivars were 25, 27, 31.5 and 33%, respectively. The highest fresh weight before and after placement in growth chamber was observed in Siah Shabestar and sour cherry was the lowest. In all the cultivars, the activity of all three enzymes were initially at maximum (369 CU), then, with the cooling of the air and the initiation of deep dormancy, the activity of these enzymes were greatly reduced (820 CU) and then again increased in the activity of this enzyme (963 CU), which is similar to other studies.
Conclusions The results of this study showed that the antioxidant metabolism in plants is influenced by seasonal cycle changes and enzymatic activity changes depending on temperature, so that sour cherry with the least chill requirement has the most activity of the enzyme catalase, peroxidase and superoxide dismutase and Siah Shabestar, which have the most chill requirement, have the least enzymatic activity. Accordingly, the enzymatic antioxidant system activity of the flower buds was relatively high at the beginning of the dormancy period, but decreased during the end of dormancy. Also, the amount of free proline at the end of dormancy and the stage of dormancy breaking was highest and the lowest was in the deep dormancy 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.
Ebrahim Abedi Gheshlaghi; Vali Rabiei; Malek Ghasemi; Javad Fattahi Moghadam; Farhang Razavi
Abstract
Introduction: It is important to understand the structural events associated with flower morphogenesis in horticultural plants, because it has many aspects of practical horticultural significance. Information about different stages of flower initiation and development is important for better management ...
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Introduction: It is important to understand the structural events associated with flower morphogenesis in horticultural plants, because it has many aspects of practical horticultural significance. Information about different stages of flower initiation and development is important for better management of the vineyardsand fruit set. Knowledge of floral ontogeny in kiwifruit is also important for the establishment of breeding programs and for the understanding of the evolutionary processes involved in the development of the floral organs. The main objective of this study was documentation of the differentiation stages of flower buds for better understanding of morphological and external changes in (Actinidiadeliciosa[A. Chev.] C.F. Liang &A.R. Ferguson var.deliciosa) cvs.Hayward (female) and Tomuri (male).
Materials and Methods: The experiment was carried out over two years in a mature 'Hayward' and ‘Tomuri’ kiwifruit vineyard at the Citrus and Subtropical Research Center of Iran (Ramsar city). Pistillate and staminate flowers development was followed from the stage of undifferentiated primordia, present in the axils of leaf primordia in dormant buds since mid-March to early June 2015 and 2016. Equally buds in diameter and size from sixth to twentieth buds on one-year old cane of Hayward and Tomuri selected at 5 to 7 days intervals. They were sampled and fixed in a solution of formalin, ethanol 70%, glacial acetic acid (2:5:1 FAA) then stored in refrigerator. Fifteen buds of each sample dissected under a Nikon SMZ645 stereo zoom microscope. The very dense pubescence within the buds was removed manually without damaging the axillary flower primordia. The remaining pubescence was removed using dissecting needles. Various stages of flower differentiation were explained with principal growth stage 5 of BBCH scale.
Results and Discussion: The first signs of the flower on Tomuri were observed 2 days before bud swelling stage (01), on the March 12th, about one month before bud break in 2015. While in the Hayward variety the first signs of the flower primordia were observed on the March 21th of 2015 (9 days later). At the beginning of bud swelling (01), flower primordia begin to differentiation and at advanced bud swelling stage (03), bracts and sepals initiated. As development proceeded, different parts of flowers initiated acropetally. Lateral flowers were formed in the bud break (07), before initiation of petals. In advanced budburst stage (09) stamen primordia appear almost immediately after petal initiation, as two whorls in 'Hayward' and as three whorls in the Tomuri cultivar. Stigma initiated in the open cluster stage (10) in Hayward cultivar about 24-25 days after bud swell stage. The process of differentiation of buds and reproductive organs in the second year was the same as the first year with the exception that differentiation began earlier than that in the first year. Climatic conditions were affected flower development and in the second year primordia differentiation began earlier two days in Tomuri and six days in Hayward than those in the first year. The advanced budburst stage (09) in Tomuri 9 days and in the Hayward 10 days was occurred earlier than that in the first year. Unlike other tree fruits, flower induction in the kiwifruit occurred about 6 months before flower initiation. Flower primordia differentiation initiated shortly before bud break stage and approximately two months before full bloom. Flower initiation and differentiation time may be partly estimated with external changes of buds development. According to cultivar, chilling and heat requirements and climatic conditions during the research, flower initiation and differentiation period have fluctuation. A reason for the difference between the development stages and different varieties can be caused by the chilling and heat requirements. The more heat requirement, the longer reproductive meristem differentiation period.
Conclusion: An understanding of the flower initiation and development is very important for the research and management of fruit trees. A knowing of flower initiation and differentiation can be developed corrective vineyard management and practices in crisis period and prepared breeding programs. Tomuri initiated and developed their floral organs earlier than those in Hayward. Different external changes in the bud may be partly used to estimate of flower development status. The results showed that flower initiation and differentiation in buds coincided with the beginning of development and elongation of bud in the early of spring.
