Pomology
N. Zeinoldini; H.R. Karimi; F. Nazoori; S. R. Sahhafi
Abstract
Introduction
Pistachio is one of the most important horticultural crops in Iran. Most pistachio orchards are located in arid and semi-arid regions of Iran, which have a lack of irrigation water. Drought stress is considered as one of the most important limiting factors for the production of plants in ...
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Introduction
Pistachio is one of the most important horticultural crops in Iran. Most pistachio orchards are located in arid and semi-arid regions of Iran, which have a lack of irrigation water. Drought stress is considered as one of the most important limiting factors for the production of plants in dry areas. Pistachio (P. vera L.) is one of the drought-resistant fruit trees due to its deep roots, but it has been reported that water stress reduces the yield and dry quality of this product. The degree of resistance to drought stress in pistachios depends on the type of rootstock, so the evaluation of pistachio species from the point of view of the rootstock is important.
Material and Methods
In order to evaluate the resistance of four pistachio rootstocks to drought stress, a factorial experiment in a completely randomized design with two drought factors at three levels (3, 6 and 9 days irrigation intervals) and a rootstock at four levels, 'Badami- e- Riz-e-Zarand', 'Ghazvini', Eurycarpa (Pistacia euricarpa), and an interspecific hybrid (P. vera × P. terebinthus) with three replications were performed under greenhouse conditions. Hybrid rootstocks produce in a breeding program using hybridization of P. vera and P. terebinthus. At the end of the experiment, the growth parameters including the number of leaves, leaf area, stem height, as well as stem diameter at a height of one centimeter above the soil surface, leaf fresh and dry weight, shoot fresh and dry weight, and root fresh and dry weight, as well as physiological and biochemical parameters including chlorophyll fluorescence (FV/FM), SPAD index, PI, Cha, Chb, total chlorophyll and carotenoids, RWC, proline, soluble carbohydrates, and phenolic compounds and concentrations of Calcium, Magnesium, Potassium and Iron elements in leaves were measured.
Results and Discussion
The results showed that drought stress reduced growth and physiological indices so that the lowest reduction in shoot dry weight was related to the hybrid rootstock and the highest reduction was related to 'Ghazvini'. It has been reported that the height and diameter of the stem of pistachio seedlings decrease significantly with the increase in irrigation period. This decrease can be attributed to the reduction of the cell turgor pressure under stress. In response to drought stress, the content of proline and soluble carbohydrates in the leaves of the studied rootstock increased. The results of this study are in line of other studies on pistachio. The highest content of proline and the lowest content of soluble carbohydrates were observed in 'Badami- e- Riz-e-Zarand’. The highest content of soluble carbohydrates belonged to Eurycarpa and hybrid rootstocks. The reason for the increase of soluble carbohydrates in the present study can be due to the decrease in the amount of photosynthesis. Drought stress exerted an influence on the nutrient concentrations within both shoots and roots, leading to an increase in potassium content. The highest concentrations of potassium in shoots and roots were noted in the Eurycarpa and hybrid rootstocks, respectively. This elevation in potassium concentration in both roots and shoots could be attributed to active absorption of this element. Plants enhance potassium absorption by expending energy to sustain stomatal conductance, cell turgor pressure, and osmotic regulation.
Conclusion
Drought stress is considered one of the most important environmental stresses, the first effects of which appear in plants in the form of reduced growth and disturbance in physiological parameters. Based on the present study, most of the measured parameters were subjected to drought treatment and the investigated rootstocks showed different reactions, so that hybrid and Eurycarpa rootstocks were less affected by drought stress than other rootstocks. According to the results of the present study, it can be postulated that Eurycarpa and hybrid rootstocks have a high potential for drought resistance.
Growing vegetables
Z. Toosi; S.J. Mousavizadeh; K. Mashayekhi; M. Alizade
Abstract
Introduction Asparagus, scientifically named Asparagus officinalis. L is a perennial plant belonging to the Asparagaceae family. Asparagus is a large genus in this genus that has about 200 species. The most important species for agricultural purposes is A. officinalis. Somatic embryogenesis is the ...
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Introduction Asparagus, scientifically named Asparagus officinalis. L is a perennial plant belonging to the Asparagaceae family. Asparagus is a large genus in this genus that has about 200 species. The most important species for agricultural purposes is A. officinalis. Somatic embryogenesis is the formation of an embryo from an-asexual cell in vitro that similar to a seed embryo, is able to develop into a complete seedling. Somatic embryogenesis is a complex molecular and biochemical process based on cellular potentiogenicity and a model in the study of plant growth. In this unique process of embryogenesis, the growth cells acquire the capacity for embryogenesis under conditions of cellular stress. Sucrose is the predominant sugar in plants for energy production and facilitates vital functions. Sucrose is converted to glucose and glucose. Sucrose is the most common source of carbohydrates used in plant tissue culture.Materials and Methods The present study was performed in the tissue culture laboratory of the horticulture department of Gorgan University of Agricultural Sciences and Natural Resources in 1399 and 1400. Native Iranian asparagus seeds with octaploid ploidy level were used in this experiment. B5 medium containing 2, 4-D with a concentration of 2 mg /l was used to induce the embryo. Concentrations of 3, 6, 9, 12 and 15% in liquid medium were used to evaluate the effect of sucrose. The pH of the culture media were adjusted to 5.7. After the induction phase, the samples entered the realization phase and the subculture were cultured in the previous environments but with the aim of emerging the embryos (realization phase) while the hormone was removed from them. After 4 weeks in the embryonic development stage, the number of globular and bipolar embryos was observed using a computer-connected stereoscope at 20 and 40 micron magnifications.Results and DiscussionThe results obtained from this study showed that there is a significant difference between different concentrations of sucrose in terms of embryogenesis formation at different stages of embryogenesis. According to the presented results, change in sucrose concentration caused a change in the formation of embryos and the highest number of spherical embryos was observed with a significant difference (p <0.001) in 9% sucrose concentration. According to the comparison results, the concentration of 9% sucrose showed the highest amount of bipolar embryo among other different concentrations. Statistical results of photosynthetic pigments and anthocyanins showed that there was a significant difference between different concentrations of sucrose. As shown in Figures 2 and 3, the highest levels of chlorophyll a, b, total and carotenoids were observed at a concentration of 9% sucrose and the lowest amount of chlorophyll a at concentration of 12% and total chlorophyll and carotenoids at concentration of 3%. Also, the results obtained from regression analysis showed that the highest amount of photosynthetic pigments and starch was observed in 9% sucrose concentration. Finally, in this study, it was found that the best concentration affecting the vegetative embryogenesis of octaploid asparagus is 9% sucrose. Conclusion Carbohydrates are the main constituents of the plant and are most used in tissue culture medium, especially sucrose for growth and differentiation. It is noteworthy that high concentrations of sucrose are not only nutritional but also change the osmotic pressure in the culture medium. The relationship between glucose status and embryonic formation has been proven. In the meantime, the capacity of sucrose to support embryonic growth is greater, so that increasing sugars such as sucrose increase the potential for embryogenesis. According to the results of the present study, 9% sucrose in B5 culture medium showed an important role in chlorophyll production and caused photosynthesis and carbohydrate metabolism in this medium to increase, and as a result, the amount of sugar and its accumulation in culture explants. Increased in this medium and eventually caused the emergence of embryos with photosynthetic pigments in the resulting seedlings. Increasing the level of sucrose also prevents rapid germination and helps the development of the root system.
Growing vegetables
N. Zeinali Pour; F. Aghebati
Abstract
Introduction
Portulaca oleraceae is used in many countries for a variety of purposes, including human nutrition and the conversion and pharmaceutical industries. The edible parts of Portulaca oleracea are the young organs, especially the brittle leaves and stems. Over time, this medicinal herb ...
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Introduction
Portulaca oleraceae is used in many countries for a variety of purposes, including human nutrition and the conversion and pharmaceutical industries. The edible parts of Portulaca oleracea are the young organs, especially the brittle leaves and stems. Over time, this medicinal herb has been forgotten. Drought, on the other hand, is a factor in the decline of crops and horticulture around the world. Given the vastness of arid and semi-arid regions in Iran and also the reduction of access to water resources, appropriate arrangements should be made for the optimal use of water in the agricultural sector. Changing the planting pattern and using useful and resistant alternative species such as drought-tolerant medicinal plants can enable the optimal use of limited water resources. GABA is an important non-protein amino acid that plays a positive role in increasing plant resistance to stress.
Materials and Methods
This experiment was carried out in 2020 as a factorial based on a completely randomized design with three replications in the vegetable research greenhouse of the Faculty of Agriculture, Shahid Bahonar University of Kerman. Experimental treatments included different levels of GABA (0, 20, and 40 mM). Treatment with different concentrations of GABA was done in two stages of 6 and 12 leaves of portulaca oleracea and foliar application and application of dehydration stress in three levels of control, medium and severe at irrigation intervals of 7, 14, and 21 days from 6 leaf stage of plants to the end.
Results and Discussion
According to the analysis of variance, the effect of GABA at different concentrations and dehydration stress on plant height was significant at the level of 5% probability. Based on the mean comparison test, the highest plant height was obtained in GABA treatment of 40 mM and irrigation intervals of 7 days (control), and the lowest of this trait was obtained in GABA zero treatment and irrigation intervals of 21 days (highest stress level). The results of analysis of variance showed that the effect of GABA at different concentrations and dehydration stress on vegetative yield was significant, the interaction between irrigation intervals and GABA was significant at 5% level. Based on the mean comparison test, the highest vegetative yield was obtained in GABA treatment of 40 mM and irrigation intervals of 7 days and the lowest in control treatment and irrigation intervals of 21 days. According to the results of the analysis of variance table, the effect of GABA at different concentrations and dehydration stress on the amount of malondialdehyde was significant at the level of 1% probability. Based on the means comparison test, the highest amount of this trait was obtained in the control treatment. Comparison of the mean of the data showed that the effect of GABA at different concentrations and dehydration stress caused a significant difference in the probability level of 1% in the proline content of the data. Based on the mean comparison test, the highest amount of proline was observed in GABA treatment of 40 mM and irrigation intervals of 21 days and the lowest amount was observed in control treatment and irrigation intervals of 7 days. As can be seen in the comparison table of means, the highest activity of superoxide dismutase enzyme was obtained in GABA treatment at 40 mM and irrigation intervals of 14 days and the lowest in control treatment and irrigation intervals was 7 days (Table 2). The results of this study showed that the effect of GABA at different concentrations and dehydration stress on the activity of catalase was significant at the level of 1% probability. As can be seen in the comparison table of means, the highest level of catalase activity was 40 mM in GABA treatment and 21 days irrigation intervals and the lowest in GABA treatment was 40 mM and irrigation intervals were 7 days.
Conclusion
The results of this study indicate that GABA is able to greatly alleviate the oxidative stress caused by dehydration in Portulaca oleracea. This effect is quite evident in oxidative parameters, especially the activity of antioxidant enzymes. The concentration of 40 mM GABA was the most effective treatment in mitigating the effects of irrigation. The results show that the use of GABA makes Portulaca oleracea tolerant to dehydration stress.
Pomology
S. Azizifar; V. Abdossi; R. Gholami; M. Ghavami; A. Mohammadi Torkashvand
Abstract
Introduction: The availability of water for irrigating crops is one of the serious challenges at present and the future of the world. Drought stress has harmful effects on plant growth and productivity, though bringing some serious changes in plant physiology and biochemistry. Drought reduces plant growth ...
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Introduction: The availability of water for irrigating crops is one of the serious challenges at present and the future of the world. Drought stress has harmful effects on plant growth and productivity, though bringing some serious changes in plant physiology and biochemistry. Drought reduces plant growth and yield by having negative effects on plants water potential, cell division, photosynthesis activity, chlorophyll content, and protein synthesis. Although olive naturally tolerates drought, studies had shown that drought undermines its growth, yield and photosynthesis. Employing some appropriate transpiration-reducing approaches could induce olive tolerance towards water deficiency. In this regard, kaolin, through raising light reflection and diminishing the rate of transpiration, is able to lessen leaf temperature in the stressed plants. Salicylic acid (SA), as a strong signaling molecule in plants, regulates physiological and biochemical functions effective in defense mechanisms and also boosts biological and non-biological factors involved in augmenting plants.. The major roles of SA in drought- stressed plants are as follows: activation of antioxidant defense system, production of secondary metabolites, synthesis of osmolytes, optimization of mineral status and maintenance of proper balance between plant photosynthesis and growth. Although some information over effects of SA and kaolin individually on stressed plants is available, to the best of our knowledge, their simultaneous effects on plants under stressful conditions has not been investigated yet. Therefore, the present study was aimed to investigate different applications of SA and kaolin (i.e. individually and simultaneously) on field-grown olives under drought condition.Materials and Methods: This research was conducted in Dalahu Olive Research Station located in Kermanshah province. This experiment was designed as a factorial experiment in the form of a randomized complete block design with 3 replications. Factors included different foliar spraying (i.e. control, 1 mM SA, 2.5% kaolin, and a combination of them in the mentioned concentrations) and irrigation at three levels (i.e. 100, 75, and 50% of water requirement). Irrigation was performed based on three-day interval schedule according to the above method by measuring daily evapotranspiration and required volume of water by considering the plant coefficients of olives and by drip irrigation.Results and Discussion: Although olive tree is a drought-tolerant plant, drought diminished its yield. The results of this study demonstrated a decrease in total yield of olive trees due to water deficit in different years. In this regard, water deficit under high temperature and low atmospheric humidity are believed to bring about a reduction in yield of drought-stressed olive. The results of this research showed that the foliar application of SA and kaolin on olive trees led to a reduction in ionic leakage and malondialdehyde (MDA) and an increase in RWC, chlorophyll content, phenol and total yield, as compared to the control. Foliar application of SA caused a significant increase in proline content and total carbohydrates, while kaolin had no significant effect on aforementioned traits. It seems that a reduction in oxidative damage and an increase in yield of olive cultivars under different irrigations manifested several defense mechanisms induced by exogenous application of SA and kaolin. In this context, kaolin was found to protect leaves and fruits from harmful ultraviolet rays and this remarkably improves the performance of drought-stressed plants by a decrease in the ambient temperature of plants in order to mitigate deleterious effects of drought such as oxidative damage, chlorophyll degradation, and lowering RWC. These results have been substantiated for different olive cultivars at different parts of the world under this condition.In the present study, SA increased chlorophyll content, RWC, proline content, carbohydrate and total phenol; as a result, the yield of SA- treated plants was higher than that in control plants. Similarly, Brito et al (5) reported that applying SA on drought-stressed olive improved osmolate accumulation, photosynthesis activities, RWC and chlorophyll content. The accumulation of phenolic compounds in SA-treated plants is believed to protect plants against stressful conditions. Therefore, the role of SA and kaolin in alleviating drought in favor of enhancing plants yield represents their efficiency under such condition. In the present study, we also employed a combination of SA and kaolin and the results showed no synergistic function between them on most traits. Therefore, to reduce the effects of drought on olive tree, it is recommended to utilize SA or kaolin separately.
Yahya Selahvarzi; Maryam Kamali; Jafar Nabati; Hamid Ahmadpour Mir
Abstract
Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to ...
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Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to their cells, tissues, and organs. Research has shown that by altering membrane properties during cold stress, metabolic balance is disturbed and with the increase in toxic metabolites, secondary damage to the plant can occur. At low temperature, decreases the efficiency of energy transfer to the center of the photosystem II. In addition, low temperatures are the main cause of the formation of reactive oxygen radicals. Also, lowering the temperature in the presence of light, due to the imbalance between light absorption and photosynthesis, increases the risk of light oxidation. Low temperature also reduces the activity of Rubisco. The amount of free proline in many plants increases significantly in response to environmental stresses such as frost stress, and stabilizes the membrane during cold stress.On the other hand, the use of some organic materials such as organic mulches increase temperature of the soil, and thus helps plant from frostbite. Use of organic mulch is widespread in agriculture due to the positive effect in soil temperature, weed control and moisture retention. Also, these mulches are effective in height, growth and flowering, early maturity and total yield of the products. Mulches in the warm seasons reduces soil temperature. Use of mulch can also help plants to withstand frostbite. Organic mulch decomposition in appropriate temperature and humidity conditions, liberates the nutrients gradually and provides for root plant and microorganisms of the soil. Organic mulches can reduce the effect of salt toxicity on plant growth and actively increase soil desalination. The most important benefit of mulch is the increase in soil temperature in the seed area, which accelerates the growth and yield of the product. Use of straw as mulch resulted in accelerated germination in cucumber. Use of straw mulch leads to an increase in temperature at night, thus protecting plants from temperature stress that has a positive effect on the growth and development of wheat.
Material and methods: In order to investigate the effect of freezing stress and using different types of organic mulch for Aquilegia plant, this experiment was conducted as a factorial experiment based on completely randomized design with four replications at Faculty of Agriculture, Ferdowsi University of Mashhad. The experimental treatments included four types of mulch (control (without mulch), 50% soil + 50% manure, 50% soil + 50% leaf needle + 50% soil + 50% rice bran) and five levels of freezing temperature (0, -5, -10, -15 and 20). Characteristics such as percentage of electrolyte leakage, relative water content, chlorophyll index and total chlorophyll, leaves number, leaf area, plant dry weight and proline leaf content were considered.
Results and Discussion: The results showed with decrease of temperature from 0 to -20 °C, stem diameter, leaf area and leaf number in bran mulch treatment decreased by 42.6%, 73.4%, 21.2% respectively, also stem diameter, leaf area and leaf number in mulch of leaf needle were 35.2%, 9/64%, 47.6%, in manure mulch were 20.20%, 46.4%, 7.8% and in the control of mulch decreased, 32.8%, 79.7%, 30.7%, respectively. At -5 °C, the amount of proline was 26% in the leaf and at -20°C, the amount of proline increased 50% compared to the control. Also, the lowest proline (0.73 μmol / g fresh weight) was obtained from the plants that treated with bran mulch. With application of, electrolyte leakage reached 63.6%, 68%, 61% and 57% in control conditions bran, needle and manure, respectively. In short, the least electrolyte leakage was observed in manure. On the other hand, when temperature dropped from 0 to -20 °C, the percentage of electrolyte leakage increased in Aquilegia. Relative water content of the leaf were 24% at 0°C, 38% at -15 °C and 23% at -20 °C. In terms of non-use of mulch, the relative water content was 36% and reached a 42% and 40% with application of manure and needle using mulch. By measuring the total carbohydrate found in Aquilegia leaf, it was observed that the amount of this trait was increased under frost stress. In general, although frost stress reduced the morphological traits of Aquilegia, use of organic mulch resulted in the improvement of these traits. The best results were observed in manure mulch.
Kambiz Mashayekhi; Hossein Sadeghi; Vahid Akbarpour; Sadegh Atashi; Yousef Ghasemi; Seyyed Javad Mousavizadeh
Abstract
Carbohydrate flow between vegetative and reproductive parts of trees is one of the determining factors of yield and fruit quality. Therefore, it varies during different times of growth season. The aim of this study was to investigate the carbohydrate content variation during growth season between leaf ...
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Carbohydrate flow between vegetative and reproductive parts of trees is one of the determining factors of yield and fruit quality. Therefore, it varies during different times of growth season. The aim of this study was to investigate the carbohydrate content variation during growth season between leaf and fruit of nectarine. So, eight nectarine trees cv. Red Gold selected randomly in the orchard and after labeling two of them combined and four replications achieved for laboratory tests. Results indicated that the highest fresh (9.3 g) and dry (3.3 g) weight of the leaves recorded at the last harvesting stage. Fresh to dry weight ratio showed a descending trend than can be indicated this fact that leaf biomass is low at primary harvesting stages and increased gradually. Chlorophyll a, b and ab reached to the highest content at the last harvesting stage. Total sugar content showed an ascending trend at second and third harvesting stages and decreased at final harvesting stage. Fruit chlorophyll content also decreased by maturation and fruit ripening; while, anthocyanin content showed an ascending trend. Fruit total sugar content decreased by third stage, two weeks after pit hardening, but increased at the final harvesting stage. Sucrose content variations show a higher value at primary stages of fruit growth in comparison with next stages and decreased by final stages. Total sugar increased at the fourth stage to third harvesting stage.
Askar Ghani; Seyyed Hossein Nemati; Majid Azizi; Mohammad Jamal Sahar khiz; Mohammad Farsi
Abstract
A pot experiment was conducted to evaluate the extract biochemical variations among 25 spearmint population. The experiment was a randomized complete design (RCD) with 25 treatments (population) and three replications. For this purpose, three rhizomes with 5 cm length were selected and planted in each ...
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A pot experiment was conducted to evaluate the extract biochemical variations among 25 spearmint population. The experiment was a randomized complete design (RCD) with 25 treatments (population) and three replications. For this purpose, three rhizomes with 5 cm length were selected and planted in each pot. All pots were kept out side. The plant samples of all treatments were harvested at full flowering stage and the most important extract biochemical factors such as chlorophyll a, b and total, carotenoide, flavone and flavonol, total flavonoide, total phenolic compound, antioxidant activity, and carbohydrate content were measured. Moreover, all characteristics of studied population were subjected to cluster analysis and correlation between factors was determined. There were significant differences among population in all studied factors. The highest and lowest chlorophyll contents (35.77 and 10.5 mg/g FW) were obtained in Fars- Khafr 2 and Mazandaran-Nour population, respectively. Among studied population, Isfahan 2, Mazandaran-Qaemshahr, Mazandaran-Nour and Yasouj were superior in extract biochemical valuable properties like antioxidant activity, total phenolic compounds, total flavonoides, and total carbohydrates. Also, some population of Fars province constituted more carotenoide and chlorophyll contents and were superior to others. Furthermore, a positive correlation was detected between antioxidant activity, phenolic compound, and total flavonoides.
