Growing vegetables
Farhad Shakarami; sadegh Mousavi-Frad; Abdolhossein Rezaei Nejad; Farhad Beiranvand
Abstract
Introduction
Salinity in water and soil stands as a crucial environmental factor that significantly hampers global agricultural production. Over recent decades, the escalating demand for irrigation in arid and semi-arid regions has intensified this issue, making it a major agricultural challenge. Salinity ...
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Introduction
Salinity in water and soil stands as a crucial environmental factor that significantly hampers global agricultural production. Over recent decades, the escalating demand for irrigation in arid and semi-arid regions has intensified this issue, making it a major agricultural challenge. Salinity stress, characterized by reduced water absorption, heightened salt uptake (especially sodium, chlorine, and boron), and the generation of reactive oxygen species, induces oxidative stress in plants, severely impacting their growth and overall performance. To enhance plant tolerance to salinity stress, elicitors are employed as a short-term and viable solution to mitigate the adverse effects of stress. Copper, serving as a cofactor and essential element for numerous enzymes involved in photosynthesis and respiration processes, plays a crucial role in sustaining natural plant growth and metabolism. Copper ions function as cofactors in enzymes like superoxide dismutase (Cu/Zn SOD) and polyphenol oxidase, contributing to the removal of reactive oxygen species. However, the absence of this element in plants cultivated in alkaline and saline soils of arid and semi-arid regions can lead to nutritional disorders. In this context, copper nanoparticles emerge as a suitable alternative to chemical fertilizers due to their quicker and more efficient impact. Their use not only mitigates the negative consequences of excessive fertilizer application but also reduces the frequency of application. The Persian leek (Allium ampeloprasum subsp. Persicum) is a valuable edible-medicinal plant native to Iran, belonging to the Amaryllidaceae family. It holds significance in Iran as a key leafy vegetable, valued for its freshness and high processing potential among horticultural plants. Given the nutritional and medicinal importance of Persian leek and the prevalence of salinity stress, this study aims to explore the impact of copper nanoparticle spray in modifying the effects of salinity stress on the morphophysiological and biochemical characteristics of Persian leek.
Materials and methods
A factorial experiment was conducted using a completely randomized design with three replications in the research greenhouses of Lorestan University's Faculty of Agriculture. The experimental conditions included daytime temperatures ranging from 20 to 28 °C, nighttime temperatures from 15 to 20 °C, relative humidity set at 60-70%, and a light intensity of 400-500 µmol m-2 s-1. The first factor involved foliar spraying of copper nanoparticles at control levels (zero), 150, and 300 mg/liter, while the second factor comprised salinity stress at control levels (zero), 50, 100, and 150 mM sodium chloride. F1 seeds were obtained from Pakan Bazr Company and planted in 1.5-liter pots, with each pot containing three plants. The copper nanoparticles were applied through foliar spraying twice on the shoot parts at the four-leaf and six-leaf stages. Salinity stress was introduced one week after the foliar application, implemented through irrigation once every three days at a level corresponding to 90% of the field capacity. The soil mixture comprised an equal ratio of agricultural soil, cow manure, and sand, maintaining a clay-sand loam texture. Following three months of applying salt stress, a comprehensive assessment of morphophysiological characteristics was carried out. This included the measurement of plant height, stem and bulb diameter, leaf count, fresh and dry weights of stem, root leaf, root volume and length, shoot/root ratio, dry matter (%), stress tolerance index, relative water content (RWC), electrolyte leakage, malondialdehyde content, photosynthetic pigments, chlorophyll stability index, as well as the activity of peroxidase and ascorbate peroxidase.
Results and Discussion
The results indicated that salinity stress had a detrimental impact on various aspects of plant growth, including a decrease in plant height, stem and bulb diameter, leaf number, and the fresh and dry weights of the stem, bulb, and root. Additionally, there was a reduction in root volume and length, along with decreased levels of photosynthetic pigments. The percentage of electrolyte leakage, malondialdehyde content, and the activity of antioxidant enzymes, namely peroxidase and ascorbate peroxidase, also increased, highlighting the adverse effects of salinity stress on plant development. The decline in plant growth can be attributed to multiple factors, including diminished cell division, ionic imbalance, reduced water absorption, impaired uptake of essential elements, and the impact of toxic ions, particularly sodium and chlorine. Other contributing factors include impaired absorption, regeneration, and metabolism of nitrogen and protein, as well as stomatal closure, collectively resulting in reduced photosynthetic efficiency. Salinity stress further leads to a reduction in soil water potential and an increase in the osmotic pressure of the soil solution. Consequently, the plant requires more energy to absorb water from the soil, leading to increased respiration and alterations in the hormonal balance of plant tissues, ultimately causing a decrease in growth and negative effects on the plant. The application of copper nanoparticles at both concentrations demonstrated positive effects on various growth components, including plant height, stem and bulb diameter, leaf count, and the fresh and dry weights of the stem, bulb, and root, as well as increased root volume and length. Additionally, the use of copper nanoparticles resulted in a decrease in the percentage of electrolyte leakage and malondialdehyde content, coupled with an increase in the concentration of photosynthetic pigments and the activity of antioxidant enzymes, including peroxidase and ascorbate peroxidase. Notably, the concentration of 150 mg/liter exhibited a more pronounced effect in enhancing plant growth, with a diminishing impact observed at higher concentrations. Copper \nanoparticles improve plant growth under stress conditions by influencing the content of cellular antioxidants and modulating the hormonal balance of plant tissues.
Conclusion
The findings of this study indicated that increased salinity stress led to higher electrolyte leakage and malondialdehyde content, along with a reduction in RWC and photosynthetic pigments. These changes caused a decline in the morpho-physiological characteristics of Persian leek. However, salinity stress also increased the activity of peroxidase and ascorbate peroxidase enzymes. Foliar application of copper nanoparticles under these conditions had beneficial effects on the plants. Specifically, at a concentration of 150 mg/liter, the negative effects of salinity stress on the morpho-physiological indices of Persian leek were alleviated. This improvement was due to an increase in the activity of antioxidant enzymes, RWC, and the concentration of photosynthetic pigments.
Medicinal Plants
M. Amani; M. Sabzi-Nojadeh; S. Alizadeh-Salteh; M. Younessi Hamzekhanlu; B. Farmani; H. Hatef Heris; Sh. Mohammadian; S. Piretarighat
Abstract
Introduction
Medicinal plants have long had a special role in the traditional agricultural system of Iran and the use of these plants as medicine to prevent and treat diseases has been considered by traditional medicine experts since ancient times. Medicinal plants with rich sources ...
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Introduction
Medicinal plants have long had a special role in the traditional agricultural system of Iran and the use of these plants as medicine to prevent and treat diseases has been considered by traditional medicine experts since ancient times. Medicinal plants with rich sources of secondary metabolites provide the basic active ingredients of many medicines. Although the biosynthesis of secondary metabolites is genetically controlled, but their construction is strongly influenced by environmental factors. One of the important climatic factors that affect the distribution of plants around the world and can cause morphological, physiological and biochemical changes in the plant is the lack of available water. Basil seems to show little resistance to water stress. For this reason, there is a need for protective mechanisms for the basil plant against stress due to water shortage. Plants are able to reduce or eliminate the effects of water shortage stress by coexisting with a number of soil microorganisms. Inoculation of the plants with Arbuscular mycorrhizal fungi (AMF) has been exploited as an applicable strategy for reducing detrimental effects of water deficit stress. Present study was performed to evaluate the effects of three AMF on some physiological responses of Ocimum basilicum under water deficit stress.
Materials and Methods
The pot experiments were conducted as factorial based on completely randomized design blocks with three replications. The experimental factors were three AMF namely Glomus etunicatum, Glomus mosseae and Glomus intraradices and various soil moisture including severe stress, moderate stress, mild stress. Water stress was applied from the beginning to the end of flowering stage. After flowering stage, plants were harvested and traits such as total phenols and flavonoids, antioxidant capacity (DPPH), malondialdehyde (MDA), catalase and peroxidase enzymes were measured. To analyze the data, first the test of data normality and uniformity of variance within the treatment was performed and confirmed. The mean of treatments was compared by Duncan test at the level of 5% probability. SAS software (Ver. 9.3) was used to analyze the data and Excel software was used to draw the graphs.
Results and Discussion
The results of analysis of variance of the effect of mycorrhiza fungus and soil moisture on the studied parameters show that the effect of different levels of soil moisture on all traits was significant. The results of analysis of variance also showed that the effect of mycorrhiza on phenol and total flavonoids, antioxidant activity, catalase and peroxidase and malondialdehyde was significant at the level of one percent probability. According to the results of analysis of variance, the interaction effect of mycorrhiza on soil moisture on antioxidant activity was significant at 5% probability level and on total phenols and flavonoids, malondialdehyde, catalase and peroxidase at 1% probability level. Results showed that AMFs improve activity of catalase and peroxidase, antioxidant capacity and total phenols which led to decrease malondialdehyde content. Antioxidants as physiologically active compounds play an important role in plant resistance to stress. Increased oxygen species due to dehydration stress are a warning sign for plants and increase the activity of antioxidant enzymes. The plant's defense system increases the production of antioxidant enzymes to neutralize toxic oxygen forms, and fungi improve the intensity of this increase, which may be due to the chemical structure of the metal isoenzymes copper, zinc, and manganese. Factors sent to make antioxidant enzymes also contain the elements zinc and calcium. Mycorrhizal fungi increase the absorption of nutrients by sending more hormonal factors and increasing the activity of enzymes, all of which can be effective in increasing the activity of antioxidant enzymes.
Conclusion
When plants are exposed to dehydration stress, reactive oxygen species in them increase. The expression of antioxidant genes and the activity of antioxidants to eliminate reactive oxygen species are increased and the antioxidant defense system is improved and the tolerance to dehydration stress in the plant is increased. Scientists believe that peroxidase is involved in metabolic processes such as hormone catabolism, defense against pathogens, phenol oxidation, binding to cell structural proteins and cell wall polysaccharides. Present study revealed that application of AMFs can be good strategy for reducing harmful effects of water deficit stress in plants. Research has also shown that impregnating seeds with mycorrhiza increases antioxidants and reduces the amount of reactive oxygen species, a characteristic of resistance induction that occurs by this antagonist.
M. Mansouri; M. shoor; A. Tehranifar; Y. Selahvarzi
Abstract
Gerbera is one of the ten important cut flowers in terms of production and consumption in the world and Iran. In this research effects of foliar application of salicylic acid and thiamine on biochemical characteristics of gerbera flower were investigated. This experiment was conducted in a completely ...
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Gerbera is one of the ten important cut flowers in terms of production and consumption in the world and Iran. In this research effects of foliar application of salicylic acid and thiamine on biochemical characteristics of gerbera flower were investigated. This experiment was conducted in a completely randomized design with four replications in the greenhouse commercial of the Golazin Maghsoud Company. Treatments were included of municipal water (control), salicylic acid 75 and 150 µM and thiamine 250 and 500 µM. Foliar application was performed with interval of two weeks in two stages. The results showed that the treatments had a significant effect on biochemical characteristics of gerbera. The greatest amount of chlorophyll a (36.6 µg/g Fw), b (17.27µg/g Fw) and total chlorophyll content (61.17 µg/g Fw) were related to Thiamine 250 µM and the highest level of carotenoids content 7.87 (µg/g Fw) was related to Thiamine 500 µM. The most reducing sugars content (181.51 mg/g Fw) reported in 75 µM salicylic acid. The highest activity of catalase and peroxidase enzyme (94.5 and 70.7 unit enzyme per minute in gram fresh weight, respectively) were related to 75 and 150 µM salicylic acid. Thus, salicylic acid and thiamine increased photosynthetic pigments, antioxidant enzyme activities.
F. Habibi; M.E. Amiri
Abstract
In this experiment, physiological responses of two citrus rootstocks [sour orange (Citrus aurantium L.) and trifoliate orange (Poncirus trifoliata Raf.)] were investigated under in vitro salt stress conditions. This study was conducted on a completely randomized factorial design. Explants (Nucellar seedling ...
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In this experiment, physiological responses of two citrus rootstocks [sour orange (Citrus aurantium L.) and trifoliate orange (Poncirus trifoliata Raf.)] were investigated under in vitro salt stress conditions. This study was conducted on a completely randomized factorial design. Explants (Nucellar seedling obtained from seeds) of both rootstocks were transferred to Murashige and Skoog (MS) solid proliferation medium containing 8.9 µM BA and 0.5 µM NAA with different concentrations 0, 50, 100, 150, 200 mM of sodium chloride (NaCl) whit six replicates. Results show that leaf chlorophyll index, photosynthesis rate, stomatal conductance, internal CO2 concentration (Ci), total protein content decreased in both rootstocks by increasing salinity levels, although there was no significant difference for above-mentioned characteristics in the interaction of salinity and rootstock. The amounts of reduction in total protein content, chlorophyll loss and internal CO2 concentration (Ci), in trifoliate orange genotype were greater than the sour orange. Also, peroxidase enzyme activity increased by increasing salinity level in both rootstocks, but, the rate of increase in the trifoliate orange was higher than the sour orange. By increasing salinity levels in the cultural medium, the uptake of sodium (Na+) and chlorine (Cl-) significantly increased in both rootstocks over 6 weeks culture period. Comparison in to trifoliate orange, sour orange less sodium and chlorine were taken up. Based obtained results, can be declared, salt tolerance has a negative correlation with Na+ and Cl- content in plant tissues, and the plant have a less Na+ and Cl- in tissues are more resistant. Thus, sour orange was more tolerant than trifoliate orange to salt stress and could be has more resistant to high concentration salinity.
