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.
Ornamental plants
Vahid Ghasemi; Abdollah Ehtesham Nia; Abdolhossein Rezaei Nejad; Hassan Mumivand
Abstract
Introduction
Salinity stress impairs the absorption of elements such as potassium, leads to decrease in water and minerals, or due to an increase in Na+ effects the absorption of other elements. Salinity of water and soil is one of the obstacles to the expansion of agriculture in most part of ...
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Introduction
Salinity stress impairs the absorption of elements such as potassium, leads to decrease in water and minerals, or due to an increase in Na+ effects the absorption of other elements. Salinity of water and soil is one of the obstacles to the expansion of agriculture in most part of the world. Salinity causes several physiological and morphological changes in plants and affects growth and photosynthesis. Salinity stress also affects the absorption of nutrients, and finally the plants sensitivity to stress increases. High concentrations of Nacl in rhizosphere reduce the water potential and cause physiological drought stress. In addition, salinity stress can cause ion toxicity and imbalance, which can damage the plant. Salinity stress has been shown to reduce plant biomass by decreasing photosynthetic capacity and chlorophyll content. As stress increases, stomatal conductance and CO2 assimilation decrease, which both negatively impact photosynthesis and lead to a decrease in plant growth. Dianthus is an annual or perennial plant that produces velvety flowers in various colors. Due to its resistance to cold and wide range of colors, it is commonly used in landscaping. However, limited research has been conducted on the response of Dianthus to environmental stress, making it important to investigate its behavior under such conditions.
Material and Method
This research was conducted at greenhouse of municipality of Khomein, Iran. The statistical design was used in the factorial experiment based on CRD. Experimental factors included salinity stress (0, 10, 20, 30, 40, 50, 60, 70, 80, 90 mM) and cultivars (Barbarin and Diana). After preparing the seeds, it is first disinfected using sodium hypochlorite and then planted in plastic pots containing soil, sand and manure. At the end of the experiment, morphological traits, stomatal conductance, photosynthesis rate, Na+, K+ and Na+/K+ was also examined. Gas exchanges were measured using an exchange measuring device (LCA4, ADC Bioscientific,Ltd., Hoddesdon, England). At the time of measuring gas exchanges, the temperature under chamber was 26-29 C and relative humidity was 58-62%. (stomatal conductivity is based on mmol/m2/s and photosynthesis in µmol/m2/s). To measure the concentration of Na+ and K+, the leaf first turned to ash (at 550 C). Then 5 ml of hydrochlorid was added to dissolve the sample and the volume of the filtered solution was reduced to 50 ml with distilled water and the concentration of Na+ and K+ was measured with flame meter. In order to measure the fresh weight of leaves and roots, plant components were separated. Fresh weight was recorded with a scale and then samples were placed in the oven (for 48 h) and weighted again to measure dry weight. Leaf area was measured with a leaf guuge device (A30325) and plant height and root length using a ruler. Statistical analysis of data was performed using Mini Tab and Excel software.
Results and Discussion
Results showed that salinity stress generally affected the growth of both carnation cultivars and reduced vegetative and reproductive growth. According to the results obtained from the study, fresh and dry weight of shoot, root and leaves, root length, plant height, stem diameter, diameter and number of flower, lateral shoot number, stomatal conductance, photosynthesis rate, K+ concentration in Diana and Barbarin cultivars decreased with increasing salinity level. Na+ concentration and Na+/K+ increased with increasing salinity and these two traits were higher in Diana than Barbarin cultivar, which indicates lower resistance of Diana cultivar. The plant's first response to stress is to reduce its leaf area, which reduces the supply of photosynthetic material to the growing parts and consequently hinders growth and flowering. Salinity stress and high osmotic potential in the rhizosphere greatly affect photosynthesis as they decrease pore conductivity. Moreover, excessive absorption of Na+ can interfere with the absorption of other elements, thereby restricting plant growth. Potassium (K+) is an essential inorganic molecule that plays a crucial role in increasing plant resistance to stress. It helps in maintaining turbidity, promoting cell development, and regulating stomatal function. In this study, salinity stress affected the growth and yield of both carnation cultivars, and with increasing stress, all morphological traits decreased. This stress also reduce photosynthesis by reducing stomatal conductance and subsequently reduce other growth characteristics. Growth reduction was observed at high salinity stress concentrations in both cultivars. However, barbarin cultivar showed higher resistance than Diana
Pomology
Sara Siahmansour; Abdollah Ehtesham Nia; Asdolhossein Rezaei Nejad
Abstract
Introduction
Reduction of water available to the plant leads to many morphological, physiological and biochemical changes in plant cell and plant organs activity will be directly disrupted. In addition to the defense systems in the plant itself, there are other ways to increase plant resistance, ...
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Introduction
Reduction of water available to the plant leads to many morphological, physiological and biochemical changes in plant cell and plant organs activity will be directly disrupted. In addition to the defense systems in the plant itself, there are other ways to increase plant resistance, including the use of plant growth regulators. Salicylic acid is known as one of the common compounds used for environmental stresses and an essential molecular signal in plant fluctuations in response to environmental stresses. This substance has a protective effect and improves the growth process of the plant. This combination stimulates the plant immune system by inducing transcription of a specific group of genes involved in the defense and development of systemic resistance. Physalis is a small fruit of the Solanaceae family that originates in tropical and subtropical regions of South America. This genus has 80 species in the world, of which the famous species Ph. minima L., Ph. angulate L., Ph. philadelphia L., Ph. alkekengi L., Ph. peruviana L., Ph. pubscens L., Ph. ixocarpa L., among these species, Peruviana species is considered due to its unique taste and high yield.
Material and Methods
An experiment was conducted at the Faculty of Agriculture research greenhouse of Lorestan University Khorramabad, Iran. (latitude 33◦ 29` N, longitude 48◦ 22` E, altitude 1125 m) in May 2018. The experimental design was factorial based on completely randomized design with three replications. The treatments consisted of 3 levels of deficit water stress (95, 85, and 75% field capacity) and four salicylic acid concentrations (0, 0.5, 1, and 2 mM). Physalis seedlings were grown into pots containing soil, sand, and manure. In this research, chlorophyll (Chl a, Chl b, total Chl) and carotenoid content, chlorophyll fluorescent parameters (F0, Fm, Fv, and Fv/Fm), fresh and dry weight of fruit, fruit diameter, fruit number, TSS and vitamin C, proline, leaf anthocyanin and shoot soluble sugar, fresh and dry weight of leaf, leaf area, root volume and plant height, were measured.
Results and Discussion
The results showed that the effect of deficit water stress and salicylic acid treatment on the measured traits including photosynthetic pigments, chlorophyll fluorescence, fresh, and dry weight of fruit, number of fruits, amount of vitamin C, proline, soluble sugar, fresh and dry weight of leaves, leaf area, plant height and root volume were significant. Foliar application of salicylic acid at a concentration of 2 mM under water stress under 75% of field capacity increases the concentration of photosynthetic pigments including chlorophyll a (25.69%), chlorophyll b (14.08%), total chlorophyll (6.70%), and carotenoid (7.26%) and increased chlorophyll fluorescence parameters including Fm (5.2%) and Fv (1.92%). Salicylic acid at a concentration of 1 mM had better results on quantitative and qualitative traits of fruit including a number of fruits (2.67%), fresh weight of fruit (10.61%), and dry weight of fruit (0.6%). Under stress conditions of 75% of field capacity, application of 2 mM salicylic acid reduced the concentration of proline (31.2%), soluble sugar (11.69%) and leaf anthocyanin (4.93%). Therefore, according to the results, the best levels of irrigation for breeding Physalis (Physalis pruviana L.) are 85 and 95% of field capacity, and the concentration of 2 mM salicylic acid as a natural modulator has an effective role in reducing the effects of dehydration stress. Stress significantly reduces the maximum efficiency of photosystem II (Fv/Fm). This adverse effect on Fv/Fm may be due to its role in inhibiting electron transfer, as well as destroying the reaction centers in PSII. Accumulation of proline under stress is because proline, as a compatible osmolyte, removes all types of active oxygen and protects the cell, and provides the necessary conditions for the plant to absorb water. Salicylic acid increases the chlorophyll synthesis and protects the chloroplast membrane from stress by removing destructive free radicals by stimulating the biosynthetic of the photosynthetic pigment pathway and reducing the chlorophyllas enzyme. It also prevents the ethylene formation by inhibiting of ACC- synthetase enzyme, which in turn prevents the degradation of chlorophyll. Salicylic acid regulates the various physiological processes such as plant growth and development.
Conclusion
According to the results, the application of salicylic acid under low irrigation stress, as a growth enhancer and stress modulator, showed good results and improved physiological traits such as increasing photosynthetic pigments (chlorophyll and carotenoids), Fm, Fv and maximum efficiency of photosystem II and improvement of biochemical traits (proline, soluble sugar and leaf anthocyanin) at a concentration of 2 mM and increase in fruit traits (fresh and dry weight, number of fruits, vitamin C and fruit diameter) at a concentration of 1 mM. Growth and morphological traits also showed an increase in fresh and dry leaf weight, leaf area, plant height at a concentration of 2 mM salicylic acid at low irrigation stress levels. Therefore, salicylic acid can be used to reduce the destructive effects of deficit water stress and increase the quantity and quality of fruit if the Physalis plant is grown in arid and semi-arid regions.
Medicinal Plants
Mehdi Rastegar; Hassan Mumivand; Alireza Shayganfar; Abdolhossein Rezaei Nejad
Abstract
Introduction: In the last decades, human activities have had adverse effects on the atmosphere and the stratospheric ozone layer, resulting in an increase in the ultraviolet radiation on the ground, especially in highlands. Among living organisms, plants are the most exposed to ultraviolet rays due to ...
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Introduction: In the last decades, human activities have had adverse effects on the atmosphere and the stratospheric ozone layer, resulting in an increase in the ultraviolet radiation on the ground, especially in highlands. Among living organisms, plants are the most exposed to ultraviolet rays due to their high and unavoidable need to light for photosynthesis, and are therefore more vulnerable to them. Plants show different responses to ambient UV radiation. The response of plants to ultraviolet light is manifested in two general ways, including tolerating the destructive effects of this radiation or/and avoiding it. The present study was conducted to evaluate the effect of ultraviolet light on growth, morphological and phenological characteristics of three cornflower cultivars under greenhouse conditions in 2018.
Materials and Methods: The experiment was performed as a split plot in a completely randomized design. Ultraviolet light was considered as the first factor in four levels (including: control, ultraviolet –A radiation, ultraviolet -B radiation and ultraviolet A + B radiations) and three cornflower cultivars (including: ‘Kornblume pink’, ‘Kornblume rot’ and ‘Kornblume blau’) as the second factor. The UV treatment was applied by lamps made by Q-Lab Co, USA. It should be noted that the 40-watt lamps used in this study were broadband and had the highest compliance with ultraviolet B (in the case of UV-B lamps) and ultraviolet A (in the case of UV-A lamps) received from the sun on the ground. So they provided the best possible simulation. During the growth period of plants, phenological traits were recorded and morphological traits and biomass traits were measured at the end of the experiment.
Results and Discussion: The results showed that UV-B radiation and simultaneous application of UV-A and UV-B radiations resulted in the reduction of the most morphological traits and yield traits including plant height, internode length, leaf width, leaf area, flowering stem length, plant fresh and dry weight, leaf dry weight, flower dry weight and number of flowers. However, flower yield was not affected by ultraviolet radiations. UV-A treatment reduced the flowering stem length and fresh and dry weight of plant in compared to the control treatment, but it had no significant effect on plant height, leaf width, leaf dry weight, flower dry weight and number of flowers. Plants response to ultraviolet radiation is very different. In many species, it has been observed that UV-A does not have a negative effect on plant growth, while, UV-B reduced the growth and yield of plants. It seems that the main reason for the reduction of plant growth and production is prevention of cell division caused by ultraviolet radiation. Degradation of plant pigments (chlorophyll) is also one of the main reason of photosynthesis decrease led to plant growth and yield reduction. The results of the present study showed that the application of UV-A reduced the number of days until the emersion of the first flower bud and the number of days until the opening of the first flower in cornflower cultivars compared to the control. UV-B treatment forced cornflowers to earlier flowering than UV-A. However, the fastest entry into the reproductive and flowering phase of cornflower cultivars was observed with the simultaneous application of UV-A and B radiations. Plants mechanisms against environmental stresses mainly depend on their origin and genetic factors. These mechanisms include three main strategies including “avoidance”, “tolerance” and “escaping”. One of the most important ways to reduce the life cycle is early flowering. It seems that the process of early flowering and completing the growth in cornflower species is a kind of stress escaping under ultraviolet radiation stress.
Conclusion: In this study, ultraviolet radiation reduced the growth and development of all three species of cornflowers. However, UV-A treatment showed the least negative effect on flower yield of plants. On the contrary, UV-B radiation and simultaneous application of UV-A and UV-B radiations reduced the growth and development of cornflowers, but did not have any significant negative effect on the flower yield (as the main useable organ of plant). Therefore, it seems that the ultraviolet radiation can be considered as a positive factor due to its positive effects on the production of secondary metabolites and early flowering and lack of significant negative effects on plant flower yield. Finally, ‘Kornblume pink’ cultivar, with higher flower yield and earlier flowering, is more suitable for cultivation than other cultivars.
Zeinab Izadi; Abdolhossein Rezaei nejad
Abstract
Introduction: While Iron (Fe) is the fourth most abundant element in the earth’s crust, it is not easily available for plant roots. Therefore, Fe deficiency is one of the major limiting factors for plant growth and development in calcareous soils worldwide. Fe deficiency are also predominant in many ...
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Introduction: While Iron (Fe) is the fourth most abundant element in the earth’s crust, it is not easily available for plant roots. Therefore, Fe deficiency is one of the major limiting factors for plant growth and development in calcareous soils worldwide. Fe deficiency are also predominant in many areas of Iran. It is an essential micronutrient for plants that play vital roles in many metabolic processes. Fe is a component of a number of molecules such as Fe-sulfur (Fe-S) and heme Fe proteins, which are required for photosynthesis, respiration and N2 fixation. However, the possibility of using split-type fertilization at different growth stages during development has been explored in other plant species for macronutrients N, P, and K. The aim of this work was to test the hypothesis that it may be feasible to decrease Fe-chelate inputs, by studying the effect of gradually increasing of Fe concentration during Calendula officinalis growing period.
Materials and Methods: In order to study the effect of gradual increase of Fe concentration during Calendula officinalis growing period, an experiment was carried out as a completely randomized design with four replications (pots) at research greenhouse of Faculty of Agriculture, Lorestan University, in 2017. Treatments contained three levels of Fe (Fe-chelate Fe (III)- Ethylenediamine-N, N' –bis ((2-hydroxyphenyl) acetic acid): 4, 20 µM and staircase method. Staircasetreatment included increase of Fe concentration, so that at first week plants received 4 µM Fe then 2 µM was added to Fe concentration weekly, to reach 26 µM. Some morphological, physiological parameters, flower characteristics and gas exchange had measured. Data of all measured parameters were subjected to analysis of variance using the SAS software (9.1.3, SAS Institute Inc.), and means were compared using a Duncan test at P≤ 0.05.
Results and Discussion: Results showed that the application of 4 µM Fe led to higher root volume, and peroxidase activity. Romera et al. (2011) reported that under Fe deficiency, strategy of plants developed morphological changes in their roots and up-regulated the expression of Fe acquisition genes. Under Fe deficiency some phytohormones such as ethylene and auxin will increased. Both hormones play pivotal role in the development of sub-apical root hair and transfer cells. Sepahvand et al (2017) investigated the effect of ascorbic acid on pelagonium graveolens characteristics under Fe deficiency and found that peroxidase activity increased under Fe deficiency. Application of ascorbic acid led to decrease peroxidase activity. Maximum biomass was obtained in plants under 35 µM Fe and staircase treatment. Maximum chl a and b, chl a+b, carotenoids, root dry weight, flower diameter, flower longevity, number of flowers, and first flower fresh weight was observed in the plants under staircase treatment. Fe plays important role in biosynthetic pathway of chlorophyll and carotenoids. In addition, plants under staircase treatment showed the maximum photosynthesis and transpiration rate. Kong et al. (2014), reported that Fe deficiency led to decrease of δ- aminolevulinic acid and protochlorophyllide as precursors of chlorophyll. Ethylene and ABA are involved in Fe-deficiency signalling in plants, and these compounds may hasten senescence (Satoh, 2011). The short flower lifetime found in the present experiment in the low Fe treatment may be due to the boost in ethylene and ABA synthesis in response to Fe deficiency. On the other hand, plants under staircase regime had higher photosynthetic pigments that led to maximum photosynthesis. Increasing flower quality, quantity and longevity related to higher photosynthesis activity. Iron is a component of a number of proteins and enzymes, such as iron-sulfur (Fe-S) proteins and non-heme iron proteins, which are required during photosynthesis (Chakraborty et al., 2012). Li et al. (2016) investigated the influence and interaction of Cadmium (Cd) and Fe on photosynthesis and reported that Cd inhibits photosynthesis activity, but Fe alleviates the Cd-induced changes in photosynthesis activity. In addition, higher MDA contents were observed in plants under 35 µM Fe and staircase treatment. Li et al. (2012) reported that the high levels of Fe led to maximum MDA contents.
Conclusion: Growing the plants with staircase treatment increased flower yield, quality and longevity. These parameters are the most important factors in growing of ornamentals plants. Whereas Fe fertilizers are so expensive, restricting the use of expensive products such as Fe (III)-chelates at some growth stages can contribute to decrease the cultivation costs and minimize environmental pollution associated to an excess of fertilizer inputs. Therefore, gradually increasing Fe concentrations during production of Calendula officinalis under soilless culture would be recommended.
Hassan Mumivand; Abdolhossein Rezaei Nejad; Shirin Taghipour; Kobra Sepahvand; Behnam Moradi
Abstract
Introduction: Drying is one of the most important post-harvest techniques for medicinal plants. Pelargonium graveolens (known as geranium) is an important, high-value perennial, aromatic shrub that can reach a height up to 1.3 m and a lateral growth of 1 m. The essential oil of P. graveolens is extensively ...
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Introduction: Drying is one of the most important post-harvest techniques for medicinal plants. Pelargonium graveolens (known as geranium) is an important, high-value perennial, aromatic shrub that can reach a height up to 1.3 m and a lateral growth of 1 m. The essential oil of P. graveolens is extensively used in the perfumery and cosmetic industries. Medicinal plants produce antioxidant compounds, which defend cells against degenerative effects of reactive oxygen species produced during oxidative stress and metabolism. Antioxidants are molecules that scavenge free radicals and reduce/prevent their damages. Therefore, the identification of natural antioxidants as preservative agents plays a pivotal role for the food, cosmetic and pharmaceutical industry. This study was conducted to investigate the effect of different drying methods (microwave-drying, oven drying and ambient-drying) on drying time and some phytochemical properties of P. graveolens.
Material and Methods: In order to evaluate the effect of different drying methods on drying time and some phytochemical properties of Pelargonium, an experiment was conducted at the faculty of agriculture of Lorestan University (Khorramabad, Iran) in 2017. The experiment was carried out based on completely randomized design with 12 treatments and three replications. The drying treatments were microwave-drying (300, 600 and 900 watts), oven-drying (45, 55 and 65 °C), ambient-drying (shade-drying at room, shade-drying in the field, sun-drying for five hours and then transfer to the room shade, sun-drying for 10 hours and then transfer to the room shade, and sun-drying) and fresh samples (as control). In all drying methods, the drying process continued until the moisture content of samples reached to 12% based on dry matter.
Results and Discussion: The results of analysis of variance showed the significant effect of drying methods on total phenol and flavonoids contents, antioxidant activity and essential oil content of the plants. The minimum and maximum of drying time (4.05 min and 6 days, respectively) was related to microwave-drying (900 watts) and shade-drying in the field, respectively. The highest total phenol (14.78 mg GA per 100 g dry matter) and flavonoid (12.83 mg quercetin per 100 g dry matter) contents were observed in plants dried at room shade and field shade, while the highest antioxidant capacity (IC50=1.02) was related to the fresh samples. The plants dried in the oven (45 °C) also had a notable phenol and flavonoid contents with high antioxidant activity. On the contrary, the samples dried in the microwave and sunshine showed the lowest amount of phenol and flavonoid contents and antioxidant activity. The highest essential oil content was obtained from oven-drying at 45 °C (0.2 %w/w based on dry mater), followed by shade-drying in the field (0.17 %w/w based on dry mater), and oven-drying at 55 °C (0.15 %w/w based on dry mater). While, the lowest essential oil content occurred with microwave-drying at 900 W (0.04 w/w based on dry mater). In this study, the amount of essential oil in the microwave-drying plants was significantly reduced by increasing the power of the microwave. The decrease in essential oil content with increasing oven temperature was also observed. The decrease in essential oil content with increasing oven temperature has also been reported in other species such as peppermint, dill, tarragon and sage and could be due to evaporation of the essential oil along with moisture losing during drying process. The results of Hamrouni Sellami et al. (2012) showed that drying in microwave at 800 w increased total phenol and flavonoid levels of sage (Salvia officinalis L.). Their results showed that as the microwave power increased from 600 to 800 watts, the total phenol content increased significantly. In research by Arslan et al., (2010), the lowest total phenol content was observed in the oven dried samples, whereas the highest total phenol content was obtained from the oven-microwave treatment and sun drying. The researchers explained that this increase was probably due to the release of phenolic compounds during drying and the reason for the decrease in phenolic compounds in the oven was attributed to the high temperature. Besbes et al., (2004) also reported that with increasing drying temperature, the amount of total phenolic compounds decreases, which may be due to the destructive effect of high temperatures on phenolic compounds. In general, it could be concluded that drying in high temperature of oven and high power of microwave reduces the amount of phenolic and flavonoid compounds, antioxidant activity and essential oil content of P. graveolens. While, shade-drying and oven-drying at 45 °C showed the least reduction in these traits compared to the fresh samples.
Conclusion: It can be concluded that shade-drying at room, shade-drying in the field and oven-drying at 45°C are more suitable for the P. graveolens .While drying treatments in the microwave and sunshine are not suitable for the species. In addition, the results showed that there was a significant relationship between total phenol content and antioxidant activity in both assays.
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.
Fateme Hasanvand; Abdolhossein Rezaeinejad; Mohammad Feizian
Abstract
Introduction: Scented geranium (Pelargonium graveolens) is a perennial plant of the family Geranium (Geraniaceae). Although CaCl2 at higher concentrations than NaCl in the soils and ground water in many areas of the word, most studies have been based on experiments that NaCl is the predominant salt. ...
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Introduction: Scented geranium (Pelargonium graveolens) is a perennial plant of the family Geranium (Geraniaceae). Although CaCl2 at higher concentrations than NaCl in the soils and ground water in many areas of the word, most studies have been based on experiments that NaCl is the predominant salt. Relatively few studies have focused on the effects of CaCl2 on plant growth and physiology. Silicon (Si) is considered as an essential element in several crops enhancing growth and alleviating different biotic and abiotic stresses. In this study, the role of Si in alleviation the deleterious effects of salinity on geranium have been studied.
Materials and Methods: This experiment was conducted in spring-summer 2014 in research greenhouse situated on the Faculty of Agriculture, Lorestan University, Khorramabad, Iran. The greenhouse temperature was 16.5–37.5 ◦C and relative humidity of greenhouse was 30–80%. Terminal stem cuttings with five nodes were obtained from mother plants in the same greenhouse and placed in a sand substrate for rooting in April. Uniform rooted cuttings were then transplanted into plastic pots (22 cm diameter and height) filled with sand substrates and grown hydroponically. Transplanting was done in May and one plant per pot was cultivated. Cultivated plants were irrigated with Hoagland’s medium electrical conductivity (EC) 1.8 dS/m, (pH) 5.8 twice a day. Experiment was arranged as factorial based on a completely randomized design with five replications. Factors consisted of daily application of 1.8, 4 and 6 ds/m CaCl2 and weekly application of 0, 0.5 and 1 mM silicic acid in nutrient solution. Plants were harvested in November. In this research some characteristics include the number of leaf, leaf area, photosynthetic pigments (chla, chlb. Total chl, carotenoids), MDA, EL, RWC, proline, number of stomata in surface unit of leaf, density of stomata and stomata index and antioxidant enzyme include CAT and POD measured.
Results and Discussion: In current study salinity decreased the number of leaf and leaf area and Si increased these characteristics. In general, decrease in the leaf area can result in a reduction in size of individual leaf of plants, decrease in the production of leaves and fall the old leaves. It also reduce the growth rate of leaf in salinity which causes osmotic effect around the roots (rhizosphere). Over time, the rate of cell division and elongation decreased, and finally this changes leads to decrease in the final size of leaf. In this study, salinity increased electrolyte leakage and the use of silicic acid prevents electrolyte leakage. Probably saturation of phospholipids with increasing salinity increased, as a result the fluidity of membrane decreased and finally increased the electrolyte leakage, silicic acid absorbed in plant and deposited in the cell membrane, causing the silica hardened. This causes in stress condition, cell membrane maintains stability and significantly reduced the amount of electrolyte leakage. In this study application Si in various concentrations under salinity stress brought a significant decrease in MDA compared with salinity alone. Salinity increased the MDA and EL so that application of1 mM silicic acid decreased EL to 16.7 and 11.9 percent plants grown in 4 and 6 dS/m EC, respectively, compared with controls. Application of 1 mM silicic acid decreased the MDA to 23.6 and 35 percent plants grown in 4 and 6 dS/m EC, respectively, compared with controls. Therefore, the present results indicate that Si can effectively ameliorate membrane lipid peroxidation, thus protecting plants from oxidative stress. Salinity affected on leaf anatomy and chloroplast ultrastructure, photosynthesis also affected by these factors. Reduction in chlorophyll at height salinity levels due to chloroplast destructive. The results showed that salinity decreased the density and stomatal index in plants and silicic acid increased these characteristics. Salinity decreased the RWC and antioxidant enzymes and application of silicic acid improved them. Increase in salinity increased the leaf proline and application of silicic acid alone in plant on stress decreased it.
Conclusion: Overall, the results of present research showed that high EC induced by CaCl2 negatively affected geranium growth, and weekly application of 1 mM silicic acid alleviated the destructive effects of stress and in high salinity the positive effect of silicic acid is more than in low salinity.
