Growing vegetables
K. Poorhossein; B. Abedy; M. Shour
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
Narmin Alavi Dehkharghani; Seyyed Hossein Nemati; Seyyed Majid Zargarian
Abstract
Introduction
As the population grows and cities expand, the demand for more green spaces has also increased. Grass is widely recognized as one of the most important ground covers in the world. However, the development of green spaces is hindered by a severe shortage of water resources and challenges ...
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Introduction
As the population grows and cities expand, the demand for more green spaces has also increased. Grass is widely recognized as one of the most important ground covers in the world. However, the development of green spaces is hindered by a severe shortage of water resources and challenges associated with managing and maintaining grass. The composition of trees and plants may cause to inhibitory or stimulation effects on crops, called allopathic effects. Therefore, understanding the allopathic effects is important to determine appropriate methods of cultivation and product management to prevent interference of allopathic substances in the growth and production of products.
Materials and Methods
This study was performed in two separate experiments as a factorial based on completely randomized design at Ferdowsi University of Mashhad. In the first experiment, the effect of three different levels of plant residue powder (zero, 0.46 and 1 g) of three types of trees (Pine, Silk and Chinaberry) on germination and growth of Lolium prenne and Festuca arundinaceae grasses with four replications in the greenhouse was investigated. The second experiment, the effect of 5 ml of aqueous extract prepared from plant residues of the mentioned trees on germination and growth of the mentioned grasses in three replications in the laboratory was investigated. At the end of both experiments, some of morophology traits (weight, length, germination index) were measured. Minitab software was used to analyze the data obtained from both experiments.
Results and Discussion
According to the analysis of variance table of the first experiment, the results show that the simple effect of grass treatment on plant and root length, fresh weight, germination percentage and rate are significantly different. In the simple effect of treatment the quantity of plant residues, all traits have a significant difference. Also, in the simple effect of treatment of plant residue kind, plant length, root length, fresh and dry weight, germination percentage and rate were significantly different. Interaction grass and the quantity of plant residues treatment and the interaction of grass and kind of plant residues treatment, all measured traits had a significant difference. The interaction triple treatments plant length, root length, dry weight, germination percentage and rate differences were observed. Therefore, in the interaction triple treatments, the most and least plant lengths were observed related to the treatment of Lolium grass with 0.46 gr of Pine residue powder and the treatment of Festuca with 1 gr of Chinaberry residue powder. Also, the most and least root lengths were related to Lollium grass with 0.46 gr of Pine plant residue powder and Festuca grass with 1 gr of Pine plant residue powder. In the triple of dry weight the most amount was related to Festuca with 1 gr of Chinaberry residue powder and the least was related to Lolium control. The most and least germination percentages belonged to the control Festuca and lollium with 0.46 gr of pine plant residue powder respectively, and in the trait of germination rate, the most amount belonged to the control Festuca and the least to the control lollium has been observed. The results of the second experiment demonstrated a significant difference in all measured traits including grass treatment, plant length, fresh and dry weight, germination percentage and rate, and simple effect of plant extract. Moreover, the interaction of grass treatment and plant residue extract showed significant differences in root length, plant length, fresh weight, dry weight, and germination rate and percentage. Comparison of the mean interaction of grass treatment and type of plant residues revealed that the control Festuca had the highest plant length, while Lolium with Silk residue extract had the lowest. The longest and shortest root lengths were observed in control Lolium and Lolium with Silk residues, respectively. The highest and lowest fresh weight were recorded in Lolium control and Lolium grass along with Silk residue extract, respectively. For the dry weight trait, the highest amount was related to the treatment of Lolium grass with pine residue extract, while the lowest dry weight was observed in Festuca grass and Lolium grass with Silk residue extract. In terms of the germination percentage trait, control Festuca and Festuca with pine residue extract had the highest germination percentage, while Lolium with Chinaberry residue extract and Lolium with Silk residue extract had the lowest. The most and least germination rates belonged to Festuca control and Lolium with Chinaberry residue extract. From these discussions, it can be concluded that the allelchemicals in the powder extract of plant residues have had a significant effect on the yield of these two grasses and have reduced growth and germination. Decreased germination due to allelopathic stress can be due to different abnormalities in metabolic activity, seed saturation potential, death of some dividing cells and embryonic abnormalities.
Conclusion
Based on the results of both experiments, it can be concluded that Chinaberry and Silk trees have a stronger allelopathic effect compared to Pine. Additionally, the performance of both grasses in response to residues and extracts containing allelochemicals was slightly different. For instance, in the second experiment, the impact of Chinaberry extract reduced plant length by 28%, root length by 89%, dry weight by 16%, germination percentage by 75%, and germination rate by 85% compared to the Festuca control treatment. Similarly, the effect of Chinaberry extract on Lolium grass resulted in a 96% reduction in plant growth, 97% reduction in root length, 98% reduction in wet weight, 50% reduction in dry weight, 89% reduction in germination percentage, and 89% reduction in germination rate compared to the Lollium control treatment.
