Pomology
S. Maslahati fard; H. Hassanpoor
Abstract
Introduction
Strawberries with the scientific name Fragaria × ananassa Dutch. It belongs to the Rosaceae family. Strawberry is one of the fruits that has found many fans around the world due to its aroma, taste and nutritional value. The main characteristics of strawberry fruit quality are ...
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Introduction
Strawberries with the scientific name Fragaria × ananassa Dutch. It belongs to the Rosaceae family. Strawberry is one of the fruits that has found many fans around the world due to its aroma, taste and nutritional value. The main characteristics of strawberry fruit quality are flavor (ratio of sugar to acid and volatile compounds) and color. Excellent plants need nitrogen in addition to carbon to meet their growth and food needs. The most vital compounds in plant living cells are proteins, which are made up of amino acid building blocks. Different amino acid sequences cause variation in the resulting proteins. Arginine is a multifunctional amino acid found in living cells and is an important storage and transport form for organic nitrogen in plants. In addition to its function as a major component of protein, it is an essential metabolite for many cellular and growth processes. Studies have shown that arginine increases the synthesis of flowering hormones related to flowering and fruiting. This amino acid is also involved in the activity of various plant enzymes. This amino acid binds to membrane nucleic acids and phospholipids and increases the activity of enzymes such as catalase. Due to the importance of producing organic products and also due to the fact that so far no study has been done on the effect of arginine on the growth and physiological characteristics of strawberry cultivar Albion. Therefore, in this study, the role of arginine on some quantitative and qualitative characteristics of albumin strawberry fruit in hydroponic conditions was investigated.
Materials and Methods
The present study was conducted in the greenhouse of the Faculty of Agriculture, Urmia University, Iran. In this study, the effect of arginine with three levels (0, 100 and 200 mg / l) on the quantitative and qualitative characteristics of Albion strawberry fruit under deficit fertigation conditions with two levels (140 and 180 ml) in a completely randomized design with 4 replications. In this study, traits such as fruit flavor, titratable acidity, soluble solids, fruit firmness, vitamin C, total phenol, total flavonoids, total anthocyanins and total antioxidant capacity were investigated. XTPlus-TA tissue analysis device was used to measure the firmness of fruit texture. Vitamin C content of fruit extract was measured by ascorbic acid based on dye reduction of 2,6 dichlorophenol indophenol (DCPIP). The Titration method was used to measure titratable acidity (TA). ATAGO manual refractometer was used to measure the amount of soluble solids. Also for measuring the taste of fruit by Voca et al. used. The Absorption difference method at different pHs was used to measure total anthocyanin. Total antioxidant capacity was assessed using the DPPH (1,1-diphenyl-2-picrylhydrazyl) method. Folin-ciocalteau method was used to measure the total phenol content. Shin et al. Method was used to measure the total flavonoid content of fruit.
Results and Discussion
The results obtained from the analysis of variance of the data showed that the measured indices were affected by different treatments of arginine and deficit fertigation. Based on the results, arginine treatment on fruit flavor, titratable acidity, soluble solids, fruit firmness, total anthocyanin, vitamin C, phenol, flavonoids and total antioxidant capacity showed a significant difference. The highest amount of soluble solids, fruit flavor and firmness of fruit texture were recorded in arginine treatment with a concentration of 100 mg / l under normal fertigation conditions (180 ml). Also, the highest amount of phenol and total flavonoids was observed at the same level of fertigation, albeit with arginine treatment at a concentration of 200 mg / l. Also, the highest amount of anthocyanin, vitamin C and total antioxidant capacity were recorded in arginine treatment with a concentration of 200 mg / l, in conditions of mild deficit fertigation (140 ml).
Conclusion
Excessive use of chemical fertilizers in agricultural production, especially in hydroponic cultivation in greenhouses, causes fertilizer wastage and as a result increases production costs as well as increases greenhouse drainage. Therefore, it has destructive effects on the environment, so reducing the amount of nutrient solution can be a management option to reduce the harmful effects on the environment and save water. Also, due to the importance of producing organic products and increasing demand, the use of healthy and organic compounds such as amino acids (arginine) to increase the quality and quality of the product, is very necessary. In the present study, arginine treatment increased the quality of strawberry fruit by affecting its photochemical content such as total antioxidant activity, vitamin C, total phenol, anthocyanin, etc. in low solubility conditions. Also, by increasing the firmness of the fruit texture, it improved the appearance quality of the fruit, which is important for attracting the consumer's attention. In general, the results showed that arginine spraying (200 mg / l) in normal solution and mild dissolution conditions can be effective in improving the quality of strawberries cultivated in hydroponic conditions.
Azam Rahimian; Mahmood Esna-Ashari; Hassan Sarikhani
Abstract
Introduction: Nowadays, crop production methods are moving towards organic farming through reducing the use of chemicals in agriculture. The new generation of seaweed extracts, like Actiwave, could be a promising approach to achieve a part of this goal. Actiwave is a metabolic enhancer derived from a ...
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Introduction: Nowadays, crop production methods are moving towards organic farming through reducing the use of chemicals in agriculture. The new generation of seaweed extracts, like Actiwave, could be a promising approach to achieve a part of this goal. Actiwave is a metabolic enhancer derived from a type of brown algae, called Ascophyllum nodosum, and contains compounds that play an important role in plant metabolism. The application of this product on various plants has often improved their vegetative and reproductive characteristics. One of the important problems in our agricultural lands is the presence of bicarbonate ion in soil (calcareous soils) or irrigation water, which increases pH around plant’s root followed by chlorosis between the veins in the young leaves resulting in a reduction or halt in plant growth. The induction of chlorosis in calcareous soils is attributed to iron deficiency due to reduction of iron absorption or availability. The use of biostimulants may help to improve plant growth under such conditions. The aim of this study was to investigate the possibility of replacing iron chelates in nutrient solution with Actiwave in two optimal and alkaline pH and its effect on some of the vegetative and biochemical properties of two strawberry cultivars in a soil-less system.
Materials and Methods: Strawberry seedlings of Camarosa and Salva cultivars were cultivated in pots containing coco-peat and perlite (1:1), followed by plant’s irrigation and nourishment through a plant nutritional program. The project was conducted in a factorial experiment (with two factors) based on a completely randomized design with three replications. The first factor was strawberry cultivar in two levels including Camarosa and Salva, and the second factor was iron treatment in four levels consisting of Hoagland nutrient solution containing iron chelate (pH=6), iron-free nutrient solution containing 0.25 ml/l Actiwave (pH=6), Hoagland nutrient solution containing iron chelate (pH=8), and iron-free nutrient solution containing 0.25 ml/l Actiwave (pH=8). Plants were fed for two months, at the end of which, the roots and shoot’s fresh and dry weight, chlorophylls a, b and total as well as carotenoids contents, catalase and ascorbate peroxidase activities in fresh leaf samples and also total Fe and active Fe in dried leaf and root samples were measured.
Results and Discussion: The results showed that the algae extract had a significant effect on all the measured parameters, so that fresh and dry weights of the aerial parts, fresh weight of the roots, as well as chlorophyll and active iron content of leaves in the treatment containing Actiwave with pH=6 was similar to the control plants. Evaluation of the activity of catalase and peroxidase enzymes in the leaf also showed that Actiwave application reduced iron deficiency stress in plants increasing the activity of these enzymes under such conditions. The reason behind these effects can be due to the Actiwave ingredient content, which includes betaine, alginates and kahydrin (derived from vitamin K). Since betaines have cytokine activity, they can increase root growth by increasing the amount of cell division. Increasing the chlorophyll content, which can be the result of reduced chlorophyll degradation, is probably due to the presence of betaines in the seaweed extract. In addition, the presence of kahydrin and alginic acid in Actiwave, with the acidification of the rhizosphere, stimulated the release of more ions around the roots, resulting in more ions received by the plant and increased their assimilation. As observed in this study, It has been proven that iron concentration in the leaf is not always an appropriate indicator for checking the state of iron in plants. Some studies attribute this to limiting the growth of young leaves and the accumulation of iron in tissues or inactivation of iron in tissues occurred through the process of alkalization in leaf apoplast. It is found that activity of catalase and ascorbate peroxidase containing iron and the iron extracted with hydrochloric acid are the most effective indices for checking the iron status in plants, and the concentration of the total iron is less important in this regard. According to the results of this study, algae extract was able to replace iron chelate in nutrient solution for growing strawberry, and so made it possible to produce this fruit by reducing the use of synthetic iron compounds. In other words, application of Actiwave instead of iron chelate is recommended in nutrient solution with pH=6.
Mohammad Hassan Bagheri; Hamid Reza Roosta
Abstract
In this study the effect of nitrogen form and different oxygen levels on growth and development and macronutrients concentrations in lettuce plants was investigated. This investigation showed that sole ammonium application caused fresh and dry weight reduction of shoot and root in lettuce plant. But ...
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In this study the effect of nitrogen form and different oxygen levels on growth and development and macronutrients concentrations in lettuce plants was investigated. This investigation showed that sole ammonium application caused fresh and dry weight reduction of shoot and root in lettuce plant. But different oxygen levels had no effect on them. Nitrogen concentration of shoot was higher in ammonium treatments compared to nitrate treatment and with increasing of oxygen levels in the presence of ammonium, nitrogen content also increased, although it was not the same in nitrate treatment. Phosphorous concentrations in shoot and root were not affected by any of treatments and their interaction. Ammonium also caused reduction of potassium concentration in shoots, but different oxygen levels and its interaction with nitrogen form had no significant effect on it. Magnesium content of shoot also decreased in the presence of ammonium, although it was not the same in root. With increase of dissolved oxygen level, magnesium content of shoot decreased in ammonium treatment, but in nitrate treatment the concentration of this element was not affected by oxygen levels. It is concluded that probably reduction of potassium and magnesium in ammonium-fed plants has a role in plant growth reduction, and it was also observed that in spite of increase in the concentration of shoot nitrogen and root magnesium with increase of dissolved oxygen level in ammonium treated plants, lettuce growth was not affected by oxygen levels.
