Growing vegetables
Keyvan Poorhossein; Bahram Abedy; Mahmood Shoor
Abstract
Introduction Urban agriculture is one of the basic characteristics of urban schematization, which helps to increase the quality of urban life via reducing the climate pollution, preserving and increasing biodiversity, as well as re-utilizing urban waste. Therefore, in recent years, urban agriculture ...
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Introduction Urban agriculture is one of the basic characteristics of urban schematization, which helps to increase the quality of urban life via reducing the climate pollution, preserving and increasing biodiversity, as well as re-utilizing urban waste. Therefore, in recent years, urban agriculture has gained significant importance due to its economic, social and cultural benefits. However, studies have indicated that urban soils can contain high concentrations of certain infrequent elements such as lead and cadmium. These heavy metals can be distinguished from other pollutants because they cannot be bio-degraded; but they accumulate in living organisms and subsequently cause diseases and various disorders even in relatively lower concentrations. Plants, like other organisms, have defense mechanisms that are activated in stressful conditions. Thus, under stress, enzymatic antioxidant systems and non-enzymatic metabolites enhance, due to the production of reactive oxygen species. Peppermint plant (Mentha piperita L) has an essential oil with medicinal properties. High levels of heavy metals cause chlorosis and necrosis, increase the accumulation of reactive oxygen species (ROS) and oxidative stress in mint plants. The present study was conducted on a regional scale in order to investigate heavy metal pollution and determine their impacts on some physiological and biochemical traits as well as the concentration of Cd and Pb in peppermint plants grown in urban green spaces.Material and methodsThis study was conducted to assess the amount of heavy metal absorption and its effect on some biochemical properties of peppermint plant (Mentha piperita L.), in Mashhad city in 2021.The experiment was carried out as a factorial in the form of randomized complete block design in three replications. The first factor (location) were Faz4 Park (with high degree of contamination) and Nasim Park (with low degree of contamination). The second factor was the times of harvest (June15, July15 and August 15). At the time of every harvest fully developed leaves were collected to evaluate physiological and biochemical traits.Results and discussionThe results of analysis of variance indicated that the effect of location was significant on all traits except for the yield of essential oil. Also, the effect of harvest time was significant on all traits except for peroxidase activity and the yield of essential oil. However, the interaction of location and harvest was significant only on phenol, flavonoid, proline, cadmium and lead concentration. The results indicated that the ascorbate peroxidase, catalase and peroxidase activities were higher in Faz 4 Park. Moreover, the highest activities of ascorbate peroxidase, catalase and peroxidase were recorded in Faz 4 + first harvest. Heavy metals cause the production of reactive free radicals and also increase the activity of antioxidant enzymes. However, the chlorophyll a, b, carotenoid and total chlorophyll contents were higher in Nasim. Thus, the highest contents of Chla, Chlb, Chltotal and carotenoid were observed in Nasim + first harvest. The higher amount of chlorophyll and carotenoids in the first harvest is due to the optimal growth conditions such as day length and sunlight and ambient temperature. In addition total phenol, flavonoid, proline, Cd and Pb elements indicated a reducing trend in Faz 4 compared to Nasim Park in different harvest times, but the amount of these traits were higher in the first harvest than in the subsequent harvests. Increased amount of total phenol in the first harvest can be related to the high air temperature at the first harvest which caused stressful conditions in this stage. Proline production also improves under heavy metal stress in order to protect the plant against toxicity. Nevertheless, the percentage of essential oil showed an increasing trend via enhancing the absorption of Pb and Cd in Faz 4 compared to Nasim Park. The higher percentage of essential oil in Faz 4 can be due to the lower growth of leaves due to the presence of more heavy elements in this area. In general, despite the fact that only the concentration of Pb was higher than the world standard level in both parks, the contamination with Cd and Pb (especially Pb) was more in Faz 4 than in Nasim Park, which was a factor in diminishing the growth traits of peppermint plants. In a case of harvest times, the first harvest recorded better growth characteristics and higher absorption of heavy metals due to the higher strength of the plant, while in the third harvest, due to spending more energy for regrowth, it had lower growth characteristics and weaker absorption of Pb and Cd metals. It was cadmium.
Ornamental plants
Mojdeh Osku; Azizollah Khandan Mirkohi; Roohangiz Naderi
Abstract
Introduction The genus Chlorophytum (also known as spider plant) which is mainly cultivated as an ornamental plant for its slash and colored leaves, specifically distributed in the pantropic regions. It is a perennial rhizomatous plant with often short and indistinct rhizomes, while with thicker ...
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Introduction The genus Chlorophytum (also known as spider plant) which is mainly cultivated as an ornamental plant for its slash and colored leaves, specifically distributed in the pantropic regions. It is a perennial rhizomatous plant with often short and indistinct rhizomes, while with thicker or slightly fleshy roots. The roots of these species are considered as one of the important phytochemical components. the use of Chlorophytum comosum as a contaminant accumulator has already been documented in the literature.This plant is a soil conditioner and can absorb lead, cadmium, Se and As while its leaves accumulate mercury. It is also able to absorb toxic organic pollutants such as formaldehyde and benzene and is also able to retain CO2. Leaf surface morphology has been shown to affect the ability of a particular plant to retain contaminants. Chlorophytum comosum introduced as a plant that requires high nitrogen. Nitrogen is an essential macro element for the growth and development of plants which involved in many physiological reactions and it is one of the elements that plants need in all their activities. The effect of N form on plant growth depends on plant species and nitrogen level of the soil. Plants absorb both ammonium (NH4+) and nitrate (NO3-) from soil solution, and these two mineral forms are their most important sources of nitrogen to supply the plant demand. Absorption of ammonium by plants requires less energy than absorption of nitrate. It seems that most plants have the best performance in a certain ratio of nitrate to ammonium (NO3-/NH4+ ratio). This ratio seems to regulate the distribution of absorbed nitrogen between the branches and roots. It may also vary between species. The optimal ratio may also depend on the environmental conditions such as pH, light intensity, and root zone temperature. This study was performed to determine the effect of different levels of ammonium nitrate on growth, yield factors and ornamental aspects of the spider plant as a desired ornamental product. The use of ammonium nitrate to meet the houseplants demand considering the supply of both types of nitrogen sources, increases the yield and quality of these plant. However, despite the importance of the nitrogen in the performance of this ornamental plant (Chlorophytum comosum), the desired amount of nitrogen for its growth and quality has not yet been reported. Therefore, the present study was conducted to investigate the effect of different levels of ammonium nitrate on the growth and physiological characteristics of spider plant to find the best level of application of ammonium nitrate fertilizer as an easily available source to increase the growth and visual quality of this plant.Materials and Methods This research was conducted based on randomized complete block design (RCBD) with four treatments and three replications. Treatments include four levels of ammonium nitrate of 100 (control), 200, 400, 600 mg-1 kg of soil. Treatments applied first at the substrate preparation process and then was applied in the one third depth of each pot, monthly. Desired factors such as morphological characteristics (plant height, leaf number, stolon number, fresh weight, dry weight, root fresh weight, root dry weight, root volume, root depth, root length, pot weight, leaf area) and physiological characteristics (total chlorophyll, total protein, texture nitrate and proline) were evaluated. Also soil analysis was performed before starting of the experiment. Statistical analyses of the data for examined traits were performed using SAS software and comparisons of means using Duncan's multiple range test, at 5% probability level.Result and Discussion The results indicated that the application of ammonium nitrate fertilizer significantly improved most of the studied traits. Supplying ammonium nitrate fertilizer at desired level meet the nitrogen demand of Spider plant during the growth and improved production of biomass. The plant height, leaf number, fresh weight, dry weight, root fresh weight, root dry weight, and leaf area were increased by increasing ammonium nitrate level. Nitrogen fertilizers play an important role for increasing plant yield by expanding shoots and producing sufficient carbohydrates. In addition to plant growth, they also affect plant morphology. Maximum amount of protein, nitrate of tissue and total chlorophyll observed in 400 mg-1kg of ammonium nitrate level. Nitrogen is one of the essential elements that plays an important role in the production of chlorophyll and protein, therefore the use of nitrogen fertilizers leads to synthesis of chlorophyll and protein at higher level. The highest amount of proline (11.20 μg-1 mL) was measured at 600 mg-1kg of ammonium nitrate level and the lowest (3.57 μg-1 mL) in the control, because with high consumption of nitrate, the plant needs more water and nitrogen is a structural component of proline. Accumulation of proline helps the plant to survive and recover after drought stress.Conclusion According to the results of our experiment, application of nitrogen fertilizer had a positive effect on growth, and consequently led to increase the plant vegetative yield. Treatment of 400 mg-1kg of ammonium nitrate level increased growth and yield factors and the ornamental aspect of Spider plant as a desired ornamental crop. Application of 400 mg-1kg of ammonium nitrate level are recommended to access an acceptable quantitative and qualitative yield in this plant.
Norollah Moallemi; Esmaeil Khaleghi; Zeinab Jafari zadeh
Abstract
Introduction: Plant establishment is difficult in some arid and semi-arid regions of Iran because of lacking rainfall and inadequate distribution and extreme heat. Previous studies stated that plant water parameters and growth characteristics such as plant height, fresh and dry weight of root, stem and ...
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Introduction: Plant establishment is difficult in some arid and semi-arid regions of Iran because of lacking rainfall and inadequate distribution and extreme heat. Previous studies stated that plant water parameters and growth characteristics such as plant height, fresh and dry weight of root, stem and leaf, which is known as the first reaction of plants, were decreased under drought stress. Therefor it is necessary to use practices with objectives to decease the effects of drought stress on plants and increasing water use efficiency. Several studies showed that various morphological and physiological characteristics in plants were influenced by ascorbic acid. In fact, ascorbic acid increased plant resistance to drought stress. The purpose of this research was to investigate the effect of ascorbic acid application on growth traits of ‘Baghmalek’ olive under 100%, 66% and 33% ETcrop < /sub> by analyzing growth traits and relative water content, stem water potential and stomata resistance. Material and Methods: This research was carried out in order to assess the effects of three levels of water deficit (100, 66 and 33 percent of evapotranspiration (ETcrop < /sub>)) and four concentrations of ascorbic acid (0, 250, 500 and 750 mg l-1) on some growth and physiological parameters of young olive plants cv. ‘Baghmalek’as a factorial experiment based on a randomized complete block design with three replications. Fresh and dry root, stem and leaf weight, leaf number, leaf area, stem diameter, relative water content, stem water potential and stomata resistance were measured in this research. Two years old olive trees (Olea europaea cv. ‘Baghmelak’) were used. Seventy two plants were grown in 10 L pots, containing a mixture of field soil: sand: manure (1:1:1). Plants were sprayed with four concentrations of ascorbic acid and irrigated every 10 days, based on the amount of evapotranspiration of plant (ETcrop < /sub>). Parameters such as relative water content, stem water potential and stomata resistance were measured at last week of the experiment and the other parameters were measured every week. Data analysis were performed using MSTATC software and means comparison were carried out by Duncan's multiple range test (DMRT) at 5% and 1% of probability levels. Results and Discussion: The results indicated the growth quality was better in plants treated with 250 mg l-1 ascorbic acid under water stress. Fresh and dry weight of root, stem and leaf growth, stem diameter, leaf number, leaf area were higher in plants treated with 250 mgl-1 ascorbic acid than untreated plants. Interaction between water deficit stress ×ascorbic acid revealed information in plant characters such as fresh and dry weight, stem diameter and leaf area simply declined as sources of water (from 100 to 66 and 33 percent) become limited, in particular in the trees which not receiving ascorbic acid treatments. However, application of 250 and 500 mg l-1 ascorbic acid enhanced the amount of relative content of leaf and water potential of stem in trees under water deficit stress. While stomata resistance was decreased in trees receiving ascorbic acid treatments. Some researcher declared that limitation of photosynthesis could be one of the most important factors for decreasing growth under water deficit stress. In addition, relative water content, cell turgor potential, reduced cell division, cell enlargement and growth plant could be affected by water deficit stress. Also the results indicated that leaf area (5952 cm), leaf number (151.7), stem diameter (6.49 mm), stem length (63.33 cm), root dry weight (18.16 g) and leaf fresh weight (9.35 g) were obtained in irrigated plants with 33% ETcrop < /sub> and untreated with ascorbic acid. Our results showed leaf number (158.7), stem length (74 cm), root fresh weight (78.08 g), stem fresh and dry weight (46.45 and 28.43 g, respectively) and leaf fresh and dry weight (13.35 and 8.45 g, respectively) were highest in irrigated plants with 100% ETcrop < /sub> and treated with 250 mg l-1 ascorbic acid. Conclusion: Water deficit stress could affect directly on relative water content, cell turgor potential and reduce cell division, cell enlargement, plants photosynthesis and plant growth. The use of ascorbic acid could effect on plants resistance to drought. In addition, various morphological and physiological traits could be influence by ascorbic acid. The results of this research indicated that 250 mg l-1 ascorbic acid concentration had more effects on water deficit and it seems ascorbic acid can be used to reducing the negative effects of drought in some regions that rainfall shortage and drought is important problems.
