Pomology
Mahmood Esna-Ashari; Esfandyar Hassani Moghadam
Abstract
Introduction: Iran has the most diverse and richest gene pool of pomegranate cultivars in the world. Drought is the most common environmental stress and the most important limiting factor of agricultural production in the world and limits production in almost 25% of the world's agricultural lands. One ...
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Introduction: Iran has the most diverse and richest gene pool of pomegranate cultivars in the world. Drought is the most common environmental stress and the most important limiting factor of agricultural production in the world and limits production in almost 25% of the world's agricultural lands. One of the most harmful effects of dehydration stress is disruption of the process of absorption and accumulation of nutrients. Among nutrients, potassium is one of the most important cations required by plants, which has been reported to accumulate during osmotic stress. The role of this cation in osmotic regulation and stomatal control has been described. Due to the fact that drought stress is one of the limiting factors for agricultural production, therefore, research on the mechanism of plant resistance to water scarcity is important. Therefore, this study was conducted to investigate the response of six Iranian commercial pomegranate cultivars to drought stress based on the amount of some leaf nutrients.Materials and Methods: The executive operations of this research were carried out in the research greenhouse of Lorestan Agricultural and Natural Resources Research Center with a temperature of 25 °C and a relative humidity of 70%. The experiments were performed due to similar climatic conditions of Lorestan and Kermanshah provinces. The plant materials used in this study were annual rooted seedlings of six pomegranate cultivars. This study is a factorial experiment with two factors: 1- Pomegranate cultivar in six levels (RababNeyriz, NaderyBadrood, ShishehcapFerdous, ArdestanyMahvelat, Malase Yazd and ShirinShavar Yazd) and 2- Drought stress in three levels including non-stress drought (80% of field moisture, control), moderate drought (60% of field moisture) and severe drought (40% of field moisture) were screened in a completely randomized design with three replications in the greenhouse. All data obtained from the experiments of this study were statistically analyzed by SAS-9.1 software and the comparison of the mean of the simple effect of the treatments was performed using Duncan's multiple range test. The comparison of the mean interaction of the treatments was performed by SAS and MSTAT-C software using Duncan's multiple range test. Graphs were drawn using Excel software.Results and Discussion: The results of this study showed that the amount of nutrients in all studied cultivars was affected by drought stress, but the response to stress was different. The amount of nutrients of iron, zinc, copper, manganese, sodium and phosphorus based on dry weight decreased under drought stress conditions while the concentration of potassium under drought stress increased. Based on the results of this study, Rabab Neyriz and Malase Yazd cultivars had more tolerance to drought stress in terms of nutrient uptake compared to other cultivars, respectively. Highest levels of iron (126.9 mg.g-1), zinc (39.9 mg.g-1), copper (13 mg.g-1), manganese (51.8 mg.g-1) and potassium (2.11% was obtained from Rabab Neyriz cultivar. Therefore, the use of this cultivar in drought stress conditions is recommended. Among the studied cultivars, Naderi Badroud and Ardestani Mehvalat had the highest sensitivity to drought stress and Shirin Shahvar Yazd and Shishecap Ferdows cultivars showed moderate resistance in this regard.Conclusion: Based on the results of this study, it showed that Rabab Neyriz and Malase Yazd cultivars have high tolerance to drought stress and are also able to show a better response to nutrient uptake under drought stress conditions. Between these two cultivars, Rabab Neyriz cultivar had higher absorption of iron, zinc, copper, manganese and potassium and was considered the superior cultivar in this regard.
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.
Shadi Mohamadi-Nejad; M. Gholami; Mahmood Esna-Ashari
Abstract
This research was conducted to study the factors affecting establishment, growth and shoot proliferation of Persian walnut, genotype Z60. Explant establishment was studied through a factorial experiment based on a completely randomized design with two factors including culture media (DKW and WPM) and ...
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This research was conducted to study the factors affecting establishment, growth and shoot proliferation of Persian walnut, genotype Z60. Explant establishment was studied through a factorial experiment based on a completely randomized design with two factors including culture media (DKW and WPM) and BA concentration (0 (control), 0.5 and 1.0 µM). Single-node explants were prepared from the young branches of Z60 trees in the middle of May. Although the effect of two culture media on the growth characteristics had no significant difference, but mean comparison of the data with this regard showed that DKW medium performed better than WPM. No significant difference was observed between the two BA concentrations, but significant difference was between two concentrations (0.5 and 1.0 µM) with 0 (control). In shoot proliferation experiment, two cytokine hormones (BA and Kinetin) in three concentrations (4.4, 6.6 and 8.8 µM) were studied in DKW medium. The data obtained from this part of experiments were analyzed through unbalanced completely randomized design. The effect of different hormonal treatments and their concentrations on Z60 genotype growth characteristics showed that 8.8 µM BA was more effective in compared to the other two treatments. However, no significant difference was observed between the three concentrations with this respect.
