Growing vegetables
Farhad Shakarami; sadegh Mousavi-Frad; Abdolhossein Rezaei Nejad; Farhad Beiranvand
Abstract
IntroductionSalinity 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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IntroductionSalinity 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 methodsA 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 DiscussionThe 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.ConclusionThe 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.
Atefeh Safaeifar; Abdolhossein Rezaei Nejad; Sadegh Mousavifard; Faizollah Shahbazi
Abstract
Introduction: Coleus (Coleus blumei Benth.) from Laminaceae family is an herbaceous, fast growing plant with colorful and decorative leaves which is used as an ornamental and pot plants. Producing short and compact potted plants is valuable in floral industry. A chemical procedure has long been ...
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Introduction: Coleus (Coleus blumei Benth.) from Laminaceae family is an herbaceous, fast growing plant with colorful and decorative leaves which is used as an ornamental and pot plants. Producing short and compact potted plants is valuable in floral industry. A chemical procedure has long been used for this purpose. However, chemical procedure is environmentally unsafe, while it is expensive. Therefore, researches are carried out to find cheaper and safer methods. Several researches have been done on height control, such as genetic manipulation, temperature management, light quality manipulation, controlled water deficit and withholding nutrients. Controlled mechanical stresses are included the potential non-chemical methods. In the present research, using a laboratory vibration simulator, the effects of vibration stress with different frequencies and durations had been examined on growth control of coleus.
Material and Methods: The experiment was conducted at the research greenhouse of Lorestan University, Iran in 2017. Uniform rooted cuttings of Coleus were transplanted in plastic pots (15 cm diameter and height) that filled with equal proportion of soil, sand and cow manure. The experimental design was a factorial based on a completely randomized design with three replications. After plant establishment, the treatments were applied every morning, with 7.5, 10 and 12.5 Hz frequencies and 0, 5 and 10 min durations, using a laboratory vibration simulator. Treatments application lasted for four weeks and then, plant height, stem diameter, total number of leaves per plant and leaf area, total number and length of side shoots, root volume and length, leaf, stem and root fresh and dry weights, relative water content, electrolyte leakage and the amounts of photosynthetic pigments were assessed.
Results: The results showed that interaction effects of frequency and duration of mechanical stress were significant at the 0.01 level in plant height, the total number and length of side shoots, root volume, leaf, stem and root fresh and dry weights, relative water content, the amounts of photosynthetic pigments, while it was not significant on electrolyte leakage. The main effects of duration of mechanical stress were significant at the 0.01 level in total number of leaves per plant and leaf area. Mean comparisons showed that with increasing frequency and duration of mechanical stress, plant height, total number of leaves per plant and leaf area, the total number and length of side shoots, root volume and length, leaf, stem and root fresh and dry weights and relative water content decreased. The shortest plant height was found in plants that treated with 12.5 frequency for 10 min which was 31% shorter than control plants. The main effects of frequency and duration of mechanical stress were significant at the 0.01 level in stem diameter, while their interaction effect was not significant. Stem diameter reduced with increasing stress duration. The stress effect on stem diameter was similar in 7.5 and 10 Hz frequencies. However, stem diameter was lower in plants treated with 12.5 Hz. Mechanical stress decreased the total number of leaves per plant and leaf area and the effects of 5 and 10 min duration were similar. With increasing frequency and duration of mechanical stress, the amounts of photosynthetic pigments increased; so that, the highest amount of those were found in plants that treated with 12.5 Hz frequency for 10 min.
Discussion: According to the results of the present research, vibration stress could control plant growth in Coleus. Stress treatments with all frequencies and durations, decreased plant height and other growth parameters i.e. the total number of leaves per plant. Leaf area, root length, plant biomass and relative water content were also decreased, while, electrolyte leakage was not significantly affected. At the same time, mechanical stress increased the amounts of photosynthetic pigments. Plants treated with 7.5 Hz frequency for 5 min showed 16% shorter plant height compared with controls, while other plant growth characteristics including stem diameter, leaf area, electrolyte leakage, MDA content and the amounts of photosynthetic pigments were similar to those in control plants. Therefore, this treatment could be recommended as a good vibration treatment for practical use. However, based on the production conditions, other vibration frequencies and durations could be chosen. In total, vibration stress using a vibration simulator could be a proper method for producing short and compact pot plants due to its cheapness and being easy to use and an environmentally friendly method.
Mehri Mahdavi-Fard; Abdolhossein Rezaei Nejad; Sadegh Mousavi-Frad
Abstract
Background and Objectives: Marigold species(Tagetes spp.) are ornamental plants which belong to Asteraceaefamily and their geographical dispersal occur mainly in temperate regions. Climate conditions, soil nutritional properties and water are considered as three important factors for plant growth. The ...
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Background and Objectives: Marigold species(Tagetes spp.) are ornamental plants which belong to Asteraceaefamily and their geographical dispersal occur mainly in temperate regions. Climate conditions, soil nutritional properties and water are considered as three important factors for plant growth. The majority of these plants are cultivated as bedding plant, flowerbed edging and mass planting from January through May in spring and early summer. During this period, plants are exposed to a wide range of temperature and light conditions. Light is an absolute requirement for plant growth and development. However, different plants have optimum requirements and both deficient and excessive light intensities are injurious. The aim of this study was to investigate the effect of different light intensity on the growth and flowering of two species of the Marigold under the late season planting dates, conditions in which young plants have to grow under high light intensity.
Material and Methods: In order to evaluate the effect of light intensity on the growth and flowering of two species of marigold (Tagetes erectaandTagetes patula), an experiment was conducted at the research station of Lorestan University (Khorramabad, Iran) in 2016. The experimental design was a split plot based on a completely randomized design with three replications. The treatments were consisted of three light intensity levels (600, 1200 and 1800 μmol m-2 s-1) as main factor and two species of marigold as a sub-plot factor. F1 seeds were growninto the pots containing equal amount of soil, sand and manure. Different levels of light intensities (1200 and 600 μmol m-2 s-1) were achieved by shading with one or two thin layers of green screen (Saran), respectively. Control plants were grown under natural light condition (no shading) with light intensity of about 1800 μmol m-2 s-1. The shading was applied at the two leaf stage until the end of the experiment. Plant height, stem diameter, numbers of axillary shoots, root length, internode length, leaf number, flower diameter, flower vase life, peduncle diameter, root, shoot and total dry and fresh weights, relative water content, chlorophyll and carotenoid content were measured at the flowering stage.
Results: The result of the present study showed that the effects of light intensity, species and their interaction effects were significant for plant height, leaf number, root length, flower diameter, leaf fresh weight, flower fresh weight, total fresh weight, leaf dry weight, stem dry weight, root dry weight, flower dry weight, chlorophyll a, carotenoids and total chlorophyll.The main effects of light intensity and species had also significant effects on stem diameter, flower vase life, stem fresh weight, root fresh weight, total dry weight and chlorophyll b. The highest mean of the most traits was found in plants grown under 600 μmol m-2 s-1, followed by that in 1200 μmol m-2 s-1. The mean comparison revealed that with increasing light intensity, plant height decreased in both cultivars. With decreasing light intensity, flower fresh and dry weight increased in T. erecta, while no differences were found in those of T. patula. The highest flower fresh and dry weight was found in T. erecta plants grown under 600 μmol m-2 s-1.In the present study, high light intensity had a detrimental effect on T.erecta as all plants died under the 1800 μmol m-2 s-1 level. However, under 600 or 1200 μmol m-2 s-1T. erecta performed much better than T. patulain most studied traits.
Discussions: The obtained results showed that by decreasing light intensity, plant height, internode length, stem diameter, leaf number, root length, number of axillary shoots, flower vase life and flower diameter increased which revealed that marigold is a sensitive plant to light intensity in late planting date, and so suitable planting date is very important for good performance of this plant. The responses of various species of marigold were different to light intensity and also toplanting date. Although the mean of most traits in T. erectawas higher compared to T. patula, T. erecta was more sensitive to light intensity compared to T. patulasince high light intensity could kill the T. erecta. Considering all the investigated traits, there is a possibility that high light intensity can affect marigold growth and development through oxidative stress. The results of present study suggest that, in late season planting conditions, T. patula and T. erectaare recommended for sunny and shaded area, respectively.
