Pomology
Zohre Rohi Vishekaii; Ali Soleimani; Mahmood Ghasemnejad; Akbar Hasani
Abstract
Introduction Olive tree, with a thousand years of cultivation history, is one of the most important horticultural crops in Iran and has always played an important economical role for orchardists. In olive orchards traits such as an increased formation of incomplete flowers, low yield of fruits and ...
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Introduction Olive tree, with a thousand years of cultivation history, is one of the most important horticultural crops in Iran and has always played an important economical role for orchardists. In olive orchards traits such as an increased formation of incomplete flowers, low yield of fruits and oil are often found as major problems. It should be noted that these traits are affected by numerous environmental and management factors from which the nutrition status is one of the most important ones. Proper nutrition plays an important role in both olive fruit and oil yield. There is a wide range of fertilizer compounds with different formulas and efficiencies available in the world market, among which nano-products are becoming increasingly popular. However, there is limited information on their efficacy in different plant species. Materials and MethodsIn order to evaluate the impact of fertilizers on olive cultivation, a research was conducted during two successive years from 2019 to 2020 in a commercial orchard on 15 year old olive tree cv. ‘Zard’, in Manjil city of Guilan province. Foliar application included five treatments using two types of fertilizers; nano (nano-chelated nitrogen and potassium: nano-NK) and chemical fertilizers (urea and potassium nitrate; NK). Treatments involved application of two concentrations from each fertilizers sources; 1.02g and 0.81g (nano-N1K1 and N1K1), 1.36 g and 1.08 g (nano-N2K2 and N2K2) of pure nitrogen and potassium, respectively. Foliar application was conducted in four stages bud-swelling, before blooming, pit hardening and shortly after harvest of table olive. Spraying with water was considered as the control. The nano-chelated fertilizers were obtained from Khazra Company, Teheran, Iran (http://en.khazra.ir). Spraying with water was considered as control. The experiment was performed in a randomized block design with three replications. The measurement of leaf nutrient status and its chlorophyll and carbohydrate contents were carried out at two times each growing season; in August (during pit hardening stage) and October (shortly after the harvest of table olive). At the green ripening stage, fruits were collected and weighted to determine fruit yield. At the end of the experiment quantity and quality traits of oil were measured. Results and Discussion The results showed that the trees under N2K2 treatment had the highest yield. In terms of mineral content, both forms of fertilizers increased the concentration of nitrogen and potassium leaf elements compared to the control trees. Chlorophyll content was affected by nano-N1K1 foliar application and carbohydrate content was affected by nano-N1K1 in the pit hardening stage and nano-N2K2 in shortly after the harvest of table olive. Nano-N1K1 treatment with the lower crop load not only increased oil content but also improved quality characteristics of olive oil (free fatty acids, peroxide value, specific ultraviolet absorbance K232, K270 and contents of pigments), total phenol content, antioxidant capacity and fatty acid composition. Generally, the results showed that olive trees responded well to fertilizer feeding. These trees produced better crop and higher quality oil in comparison with control trees. According to the results, fruit yield is better under urea and potassium nitrate treatment, and the quality of olive oil is more stable after nano-chelated nitrogen and potassium foliar application. It seems that the reason for the high amount of fruit yield with N2K2 in comparison to the slow-release property of nano-fertilizers is that using nitrogen and potassium in the form of ordinary chemical fertilizer regulates the biosynthesis, conversion and rapid translocation of assimilates and mineral elements into reproductive structures, which resulted in soaring yield. We assumed that nano-N1K1 foliar spray in the pit hardening stage and shortly after the fruit harvest for table olive might export the assimilation into the fruit to fulfill cell metabolism requirements for oil synthesis. Conclusion The current findings indicated that two of four treatments, i.e. nano-N1K1 and N2K2, could be more effective on olive trees in terms of general fruit and oil attributes. It was remarkable that nano treatment with a lower concentration could provide adequate beneficial effects on quality characteristics of olive oil and is in line with good management strategies regarding the preservation of the environment. To the best of our knowledge, the current work is the first report considering the application of nano-chelated nitrogen and potassium and their is use as a foliar application on olive trees. Additional studies would be necessary to further optimize the concentration and timing of the applications with these new formulations.
َAysan Samadi; Akbar Hassani; Majid Gholamhoseini
Abstract
Introduction: Plant growth promoting bacteria are beneficial microorganisms that produce plant resistance to a variety of biological and non-biological stresses, including drought, extreme temperatures, salinity, toxic metals, etc, and increase plant productivity and yield. The use of these microorganisms ...
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Introduction: Plant growth promoting bacteria are beneficial microorganisms that produce plant resistance to a variety of biological and non-biological stresses, including drought, extreme temperatures, salinity, toxic metals, etc, and increase plant productivity and yield. The use of these microorganisms as biological agents in increasing soil fertility and improving agricultural productivity has been studied by many researchers, so a proper understanding of their effect on drought resistance can be effective in water resources management. Useful in field and reducing environmental effects of using chemical fertilizers. The purpose of this study was to investigate the effect of some bio-fertilizers on growth and some physiological and biochemical characteristics of red radish and in comparison with potassium sulfate application under drought stress.
Material and Methods: In other to investigate the effect of application of bio-fertilizers containing potassium-soluble bacteria (Pseudomonas koreensis and Pseudomonas vancouverensis), phosphorus-solubilizing bacteria (Pseudomonas putida) and nitrogen-fixing bacteria (Pantoea agglomerans) on plant growth and function, this experiment was done with 10 treatments and three replications in the form of completely randomized design in greenhouse. Finally the statistical population consisted of 30 pots of 10 treatments and three replications for red radish. Drought stress was applied in such a way that the apparent symptoms of stress were seen in the plants and the amount of water used was the same for all plants. The experiment was carried out in greenhouses and nylon pots with a capacity of 6.5 kg were used. The soil was prepared using a calcareous soil of Zanjan University research field. Its absorption was less than critical. Organic matter content was 0.4% and lime equivalent was 14.1% pH of soil 7.57 and EC of abstract soil paste was 2.21. Pots were treated with municipal water for 25 days after planting. EC values of water was 400 µS / cm that irrigated the plants every three days. The desired bio-fertilizers were added to the pots with irrigation water. After 25 days, 15 pots of treatments 4 to 6 were subjected to drought stress. 40 days after planting before drying of the plants, weight, moisture content of plant tissue, leaf proline content, total free amino acid, and total soluble sugars in leaf extract were measured. Analysis of variance was performed using SAS software and LSD test at the 5% level was used to compare the means.
Results and Discussion: Results of analysis of variance showed that the effect of different treatments on aerial fresh weight was significant at 1% level. Fertilizer treatments under stress and non-stress conditions significantly increased aerial fresh weight. Among non-stress treatments, the highest fresh weight was obtained from treatment 2 (10.03 g / pot) and the lowest was in control treatment (6.55 g / pot). Among the drought stress treatments with application of different fertilizers used, treatment 8 (9.19 g / pot) had the highest and treatment 6 (7.04 g / pot) had the lowest fresh weight. Application of potassium sulfate fertilizer increased the fresh weight of aerial part both under stress and non-stress condition. Potassium soluble bio-fertilizer alone and in combination with other bio-fertilizers increased radish aerial fresh weight, which was not significantly different from potassium sulfate fertilizer. In radish, drought stress affected the tuber fresh weight more. The radish plant uses the water of the tuber reserve in drought stress so that the leaves are less susceptible to stress. In non-stress conditions, application of potassium sulfate fertilizer and bio-fertilizers in radish increased yield. Potassium sulfate effect was greater. In stress conditions, the effect of bio-fertilizers was more than potassium sulfate in stress condition. The effect of potassium soluble bio-fertilizer application was almost identical with the combined application of different biofertilizers. Drought stress increased the concentration of proline, amino acids and soluble sugars in leaves and tubers of radish. Increasing concentration of these compounds indicated that plants were resistant to drought. Application of potassium sulfate and bio-fertilizers decreased these concentration and the effect of bio-fertilizers was more than that of potassium sulfate. The amount of ion leakage also increased under drought stress but leakage decreased by using potassium sulfate and bio-fertilizers. Drought stress also reduced the starch concentration in leaves and tubers of radish, which is a consequence of drought stress.
Conclusion: In general, application of potassium sulfate and bio-fertilizers moderated the effects of drought stress and in some cases the effect of biofertilizers was greater. Integrated use of bio-fertilizers was not significantly different from the use of potassium soluble bio-fertilizer alone. So, the results of this study showed that the use of bio-fertilizers can be included in the plant nutrition program as a factor in reducing the negative effects of stress on plants.
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.
