Growing vegetables
Nasrin Farhadi; Mojgan Abdeshahian; Samane Mottagi
Abstract
Introduction
Currently, salinity stress is one of the most important challenges in the agriculture and is the main growth limiting factor of many plant species. Saline stress adversely affects the plant's physiological and biochemical process which leads to a considerable reduction of plant growth ...
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Introduction
Currently, salinity stress is one of the most important challenges in the agriculture and is the main growth limiting factor of many plant species. Saline stress adversely affects the plant's physiological and biochemical process which leads to a considerable reduction of plant growth and yield. Shallot (Allium hirtifolium Boiss.) is a perennial plant from the Alliaceae family, which is one of the native and valuable plants of Iran and wildly grows in the slopes of the Zagros Mountain range. The nutritional and medicinal value of shallots is due to the presence of sulfur compounds, especially allicin in the bulbs. The present study was conducted to investigating the effect of foliar application of salicylic acid on the changes of growth, physiological and biochemical traits of shallot under different levels of salinity stress in factorial design based on a completely randomized design with three replications. The investigated treatments were four levels of salinity (0, 30, 60 and 90 mM NaCl) and four levels of salicylic acid (0, 1, 1.5 and 2 mM). Distilled water (control) and salicylic acid (1, 1.5 and 2 mM) were foliar sprayed on the whole plants at 4, 6 and 8 weeks after sowing date. At the end of the growing season (beginning of yellowing of the leaves of the plants), growth, physiological and biochemical traits were evaluated. Evaluation of lipid peroxidation, osmolality compounds and activity of antioxidant enzymes was carried out in the leaves of treated plants and the amount of pyrovat and allicin was measured in harvested shallot bulbs.
Results and discussion
Various abiotic stresses restrict plant productivity, and many efforts have been done to reduce plant growth inhibition by alleviating the disorder’s effects of these stresses. Exogenous application of plant growth regulators has been reported as an economic procedure to improve plant resistance to environmental stresses. It has been previously reported that salicylic acid as a signaling molecule alleviated the adverse effect of different stress condition. In this experiment, shallot resistance to saline condition was enhanced by the foliar spray of salicylic acid. The results showed a significant link between salicylic acid treatment and improvement of bulb biomass under saline conditions. Lipid peroxidation regards to accumulation of malondialdehyde and hydrogen peroxide increased with increasing the salinity intensity. Also, saline stress significantly enhanced the proline and glycine betaine content in stressed plants of shallot. The plant antioxidant activity induced under stress condition by increased the total phenol content as well as the activity of catalase, peroxidase, ascorbate peroxidase and superoxide dismutase enzymes. The pyrovat and allicin content of shallot bulb was increased with increasing salinity stress. The decreased in the photosynthetic pigments (total chlorophyll and carotenoids) led to a decrease in plant growth with the intensifying of stress level. So that the lowest leaf area, fresh and dry weight of bulbs were obtained in severe salinity stressed plants (90 mM NaCl). Foliar application of salicylic acid through increasing the antioxidant compounds (total phenol, pyrovat and allicin) and the activity of antioxidant enzymes (CAT, POX, APX and SOD) limited the of hydrogen peroxide accumulation and lipid peroxidation. The induced accumulated osmolyte compounds proline and glycine betaine was decreased in treated plant with salicylic acid. The treatment of salicylic acid considerably improved the chlorophyll and carotenoids content especially in salinity stressed plants. So that the applied of salicylic acid, especially at concentration of 2 mM, reduced the harmful effects of salinity stress on plant growth and bulb yield by increasing the photosynthesis pigments and consequently photosynthesis efficiency. Also increased growth in the treated plants with salicylic acid has been attributed to changes in the concentration of plant hormones, especially auxins and cytokinins (the most important plant growth stimulating hormones). Nevertheless, the growth reactions of treated plants to salicylic acid are different depending on the used concentration, the plant species and the growth stage at the treatment time.
Conclusion
In the several literatures the salicylic acid effects on plant growth enhancement under unfavorable environmental condition attributed to salicylic acid-induced changes in plant biochemical and physiological processes. Based on the obtained results, the salinity resistance of the shallot plant in response to salicylic acid is related to the increased antioxidant capacity of the stressed plants, which leads to the improvement of the photosynthetic pigments, and consequently plant growth and bulb biomass under saline condition. Although the present study was performed in the glass greenhouse, the obtained finding showed that salicylic acid application could also be a promising treatment for improving salinity tolerance of A. hirtifolium under field conditions.
Seyyed Ali Akbar Bagherian; Askar Ghani; Ali Reza Sanie Khatam
Abstract
Introduction: Citrus trees are among the most important tropical and subtropical fruit trees in the world. In recent years, newfound disorders have become a serious danger to citrus growing. In the last two years in Jahrom city and surrounding towns, there have been numerous reports about the rapid drying ...
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Introduction: Citrus trees are among the most important tropical and subtropical fruit trees in the world. In recent years, newfound disorders have become a serious danger to citrus growing. In the last two years in Jahrom city and surrounding towns, there have been numerous reports about the rapid drying of whole of citrus trees or parts of them. Following studies by expert groups, the problem was referred to as "Citrus decline". Most researchers have divided the main causes of decline into biotic and abiotic groups. In fact, the disorder of citrus decline refers to any type of disorder, disease or problem that can ultimately lead to tree weakness and loss. In fact, decline can be considered a synonym for death. Materials and Methods: In this study, 64 orchards located in the cities of Jahrom, Juyom, Khafr and their suburbs were studied. Each orchard consisted of at least 100 trees of ‘Lisbon’ cultivars (one to ten years old). Evaluations were carried out periodically and with a two-month intervals from March 1976 to November 1977. On the one hand decline rate and on the other hand desiccating rate (tree with complete drying) were measured. Average monthly air temperature, sodium absorption ratio (SAR), irrigation water, soil texture, manure consumption, irrigation amount and methods, and spatial and temporal distribution of irrigation water were measured. Longitude, latitude and altitude were recorded using GPS. The meteorological data were obtained from weather station of Jahrom city. Soil sampling was performed using standard methods from all orchards. After determining the soil texture type, in order to data convert from qualitative to quantitative according to the amount of clay available, the numbers 1 to 10 were assigned to each sample. Number 5 was considered as medium and standard soil texture. If manure was applied, one unit was added to the soil texture score of less than 5 and one unit was subtracted from the numbers above 5. The presence or absence of shading on the studied trees (Green lace or palm tree) was assigned to zero and one numbers, respectively. Numbers zero and one were assigned to applied or non-applied soil sodium solute reducing fertilizers, respectively. The amount of clay, SAR (sodium absorption ratio) in irrigation water were obtained using the usual measurement methods in soil and water experiments. Data were analyzed using SPSS software (version 25) and Path analysis diagram was plotted using AMOS software (version 24). Multivariate statistical analyzes including factor analysis, correlation, cluster analysis and path analysis were performed to determine the relationships between variables and the percentage of decline. Results and Discussion: According to the results of factor analysis, the first four factors accounted for 80.53% of the total variation. The first component (soil physical properties) including clay and soil texture accounted for 26.37% of the total variance. The second component (salt evaporation and accumulation) included temperature, mean age of the trees, and the rate of sodium absorption ratio (SAR) with accounting of 23.95% of the total variance. Significant correlations were observed between decline and mean tree age, decline and clay percentage, decline and presence of shading. Almost all of the declined trees reached the full drying stage, which is justified by the high correlation of the decline with desiccating (r=0.90 **). Percentage of decline had the highest correlation with tree age (r=0.67 **). Percentage of complete desiccating of the tree was also highly correlated with tree age (r=0.51 **). T-test to determine the correlation between two-level nominal variables such as application of shading (presence or absence of shading) and anti-salinity compounds (application or not application of salinity fertilizers) with decline occurrence was used. The mean percentage of decline was 29.66% in trees under shade and 57.40% in trees without shade. In general, the rate of decline in trees without shading is twice more than trees with shading. Path analysis identified the direct and indirect effects of variables on the rate of decline. Conclusion: It was generally found that the decline is a multivariate physiological disorder that largely, can be controlled by some orchard management operations. In the meantime, temperature control and soil texture correction are important, especially in older trees. Increased temperature is one of the major causes of citrus decline that is also indirectly associated with other deteriorating factors. Soil quality changes gradually due to various factors so its correction is very important in reducing the incidence of this disorder.
Mohammad Hossein Sheikh Mohammadi; Nematollah Etemadi; Ali Nikbakht; Mostafa Arab; Mohammad Mehdi Majidi
Abstract
Introduction: Drought and salinity are the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool season grass species are not well adapted to extended periods of drought and salinity stress. The decline in turf quality caused by drought and salinity ...
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Introduction: Drought and salinity are the most detrimental abiotic stresses for turfgrass growth across a wide range of geographic locations. Most cool season grass species are not well adapted to extended periods of drought and salinity stress. The decline in turf quality caused by drought and salinity stresses is a major concern in turfgrass cultivation and management. Therefore, developing management practices for improving drought and salinity resistance of turfgrasses has become imperative in arid and semiarid regions. Grass genotypes differ in their responses to drought and salinity stresses, which involve changes in morphological and physiological aspects. Understanding of relative involvement of each morphological and physiological characteristic in drought and salinity tolerance is important in selecting grass genotypes to facilitate breeding of drought and salinity-tolerant genotypes. The purposes of this research were to make selections of genotypes tolerant to drought and salinity stress for turfgrass management program.
Materials and Methods: To study some morphological and physiological responses of six Iranian crested wheatgrasses (Agropyron cristatum L.) under drought and salinity, an experiment was conducted in the greenhouse of College of Abureyhan, University of Tehran, Iran. Six Iranian Agropyron cristatum genotypes were collected from six locations in Iran. Agropyron cristatum genotypes were planted in polyvinyl chloride tubes and kept in the greenhouse. Pots were filled with sandy loam soil which had been sterilized in an oven at 160ºC for 6 h. Irrigation was applied as needed to prevent any visible stress during grass establishment. Grasses were watered three times weekly to maintain plants under well-watered conditions and soil moisture at field capacity. The experiment consisted of three treatments: 1) well-watered plants were irrigated three times per week with distilled water (control), 2) Drought stress was imposed by withholding irrigation for 45 days (drought stress), and 3) plants were irrigated daily with 100 mL of 9 dS.m–1 NaCl solution (salinity stress). To avoid primary salinity shock, the soil in each pot was drenched with 100 mL NaCl solution at incremental electrical conductivity (EC) by 3 dS.m–1 per day until the final EC reached 9 dS.m–1. Data were subjected to analysis based on a split-plot design with water treatments as main-plots and genotypes as sub-plots. Irrigation treatment as the main factor in three levels (control, drought, and salinity) and crested wheatgrass at six levels were considered as sub-plots. Studied characteristics such as height, turf quality, chlorophyll content, soluble carbohydrates, relative water content, electrolyte leakage, root penetration, and effective root depth were recorded. Statistical significance was tested using the analysis of variance procedure in SAS 9.1 (SAS Institute Inc., Cary, NC). Differences between the means were determined using the Fisher’s protected LSD test at the 5% probability level.
Results and Discussion: The results of this study showed that drought and salinity stress decreased the quality of crested wheatgrass masses, and reduced the level of quality varied among the masses. Throughout the experiment, ‘Sabzevar’ and ‘Damavand’ under drought conditions and ‘Sabzevar’, ‘Arak’ and ‘Damavand’ under salinity conditions maintained higher Turf quality compared with other genotypes. Total chlorophyll content of ‘Sabzevar’ and ‘Damavand’ were higher than other genotypes under drought and salinity conditions. The maintenance of higher chlorophyll content has been associated with better drought and salinity tolerance in plant. The soluble sugar content of ‘Sabzevar’ and ‘Damavand’ under drought conditions and ‘Sabzevar’, ‘Arak’ and ‘Damavand’ under salinity conditions were higher than other genotypes during the experiment. Soluble sugar content is an important compatible osmolyte in plants. Increased accumulation of soluble sugar content in stressed plants may be an adaptation process and resistance strategy to abiotic stresses in plants. Throughout the experiment, ‘AEKQI’, ‘Sabzevar’ and ‘Damavand’ genotypes under drought conditions and ‘Sabzevar’ genotypes under salinity conditions maintained higher relative water content in compared with other genotypes. Higher RWC indicates the ability of the leaf to maintain its higher water content under stress conditions with the simultaneous capability of the root system to take up adequate water. Based on morphological and physiological analysis for drought and salinity tolerance in investigated genotypes, the tolerance ranking would appear to be ‘Sabzevar’ > ‘Damavand’ > ‘Arak’ > ‘Urmia’ = Takestan > ‘Hashtgerd’ under drought stress and ‘Sabzevar’> ‘Arak’ > ‘Damavand’ > ‘Takestan’ = ‘Hashtgerd’> ‘Urmia’ under salinity stress. The results of this study showed that ‘Sabzevar’ and ‘Damavand’ genotypes had good tolerance to drought stress, and ‘Sabzevar’ and ‘Arak’ genotypes had good tolerance to salt stress than other Iranian crested wheatgrass genotypes.
Bahram Abedy; Behnam Esfandiyari
Abstract
Introduction: Citrus is highly sensitive to water and soil salinity. About 13 percent decrease of citrus yield per each 1 dS m -1 increase in salinity above 1.4 dS m-1. Arbuscularmycorrhizal (AM) fungi are probably distributed in most soils and approximately 90% of higher plant species examined interact ...
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Introduction: Citrus is highly sensitive to water and soil salinity. About 13 percent decrease of citrus yield per each 1 dS m -1 increase in salinity above 1.4 dS m-1. Arbuscularmycorrhizal (AM) fungi are probably distributed in most soils and approximately 90% of higher plant species examined interact with AM fungi.AM growth hyphae increased root level, water absorption efficiency and nutrient distribution specially phosphorus and zinc. More biomass and less proline content in citrange "carrizo" inoculated with Glomusintraradices in compare with non-inoculated treatment under different salinity levels. Two symbiosis AM (Glomusmosseae and Paraglomusoccultum) through growth improving, photosynthetic rate and root structure could reduce adverse effects of salinity under 100 mM sodium chloride concentration. We analyzed the impact of two mycorrhizal fungi under salinity stress. Our objectives were to determine how AM symbiosis can alleviate adverse effect of salinity and which of our mycorrhizal fungi show better results.
Materials and Methods: Seed of Flying dragon were sterilized by immersion in 70% alcohol for 4 min, rinsed 5 times with distilled water and germinated in jiffy pots at 27ºC. 25 g of fungi (Glomusmosseae and Paraglomusoccultum) per pot were used while non-AM fungi treatments received the same weight of growth media. The experimental design conducted in a completely randomized design as a factorial form. First factor was four levels of salinity (0, 50, 100 and 150 mMNaCl) and the second factor was two different genotypes of mycorrhizal fungi. Six replicates of each treatment were applied. Control treatments were irrigated with distilled water. Shoot and root dry weight were measured. Concentration of proline was measured by the method of Bates et al (3). AM colonization was estimated in according to with Hashem et al (14) with using light microscopy. Relative water content (RWC) was measured by Wu and Xia (28). The sucrose and glucose were determined by Wu et al (29) method. Na+, K+ and Ca+ concentrations in leaves were measured by using atomic absorption spectrometer. The data were analyzed by two factor ANOVA using JMP 7 software. Least significant difference (LSD, α
Mehri Yusefi; Seyyed Jalal Tabatabaie; Jafar Hajilou; Naser Mahna
Abstract
Salinity affects the yield and quality of fruits crops as result of modifying water and nutrient uptake. In split root system, it should be possible to reduce the deleterious effect of salinity on the plant growth. Therefore, an experiment was conducted on strawberry with different concentration of NaCl ...
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Salinity affects the yield and quality of fruits crops as result of modifying water and nutrient uptake. In split root system, it should be possible to reduce the deleterious effect of salinity on the plant growth. Therefore, an experiment was conducted on strawberry with different concentration of NaCl (0, 30, 60 and 90 mM) in a completely randomized blocks design in studding hydroponic greenhouse. The roots were divided into two portions and either even or uneven salinity was applied to the root portions. The treatments consist of 0:0, 0:30, 0:60, 0:90, 30:30, 60:60 and 90:90 with three replications. In general, the increased salinity reduced photosynthesis rate but in uneven salinity the photosynthesis rate was increased. Proline concentration was reduced in 0:0 treatments but increased in 0:30 and 30:30 treatments. Ca, N, P and K concentrations were reduced by increasing salinity, but were increase in uneven salinity. The highest concentrations of Cl and Na were observed in 60:60 and 90:90 salinity treatments. Na and Cl concentrations were reduced in uneven salinity in the root zone so that in 0:30 treatments, the concentration of Na were 20% lower than that in 30:30 treatments. Based on the results of this study the application of uneven salinity in a concentration of 30 mM could be recommended for growing strawberry in salinity stress conditions.
Shima Alaei; Enayatollah Tafazoli
Abstract
Salinity is a limiting factor for plant growth and crop production. A study was conducted to determine the salt tolerance of olive (Olea europaea cv. Roughani) and its effects as combined with application of kinetin and cycocel plant growth regulators on Na and K distribution. The experiment was carried ...
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Salinity is a limiting factor for plant growth and crop production. A study was conducted to determine the salt tolerance of olive (Olea europaea cv. Roughani) and its effects as combined with application of kinetin and cycocel plant growth regulators on Na and K distribution. The experiment was carried out in a completely randomized design with factorial arrangements with four replications. Accumulation of Na and K in aerial parts and roots of plants were determined. The results indicated that increasing salinity level caused a increase in Na content but a decrease in K/Na ratio. Sodium concentration was higher in roots. At 200 mM salinity leaf and shoot Na and increased significantly at 5% level. Also at 100 and 200 mM salinity, Leaf K decreased significantly at 5% level. K/Na ratio at 50,100 and 200 mM salinity level decreased. Application of 250 mg/l kinetin at the 200 mM salinity increased leaf Na that was significantly different at 5% level ,DNMRT. Application of 500 and 1000 mg/l cycocel, decreased shoot K (at the 100 mM salinity) and leaf K (at the 0 and 50 mM salinity). The decrease was statistically significant (p
