جستجوی مقالات مرتبط با کلیدواژه « پراکسیداز » در نشریات گروه « آب و خاک »

Grass is one of the most important cover plants in most green spaces, and considering that Iran is considered one of the dry and semi-arid regions of the world, water and soil salinity affects the growth of plants, as a result, using salt-resistant grass is one of the solutions to create green space in these areas. Therefore, the purpose of this research is to investigate the salinity tolerance of sport turfgrass caused by sodium chloride and potassium chloride salts.

In April, sports grass seeds were planted in an area located in Karaj province in the form of a r randomized complete block design with three replications in plots of 2 m2 (1 x 2 m2) and were cultivated with a density of 40 g m-2. The experimental treatments included sodium chloride and potassium chloride salts with concentrations of zero, 25, 50 and 75 mg l-1. After about 5 weeks of planting the seeds, salt stress was applied for one month through irrigation with salts twice a week and each time with 12 liter of salt solution and then sampling was done to evaluate fresh and dry weight of shoots and roots, total chlorophyll, proline, protein and activity of superoxide dismutase and peroxidase enzymes.

Data analysis showed that the treatments had a significant effect on the assessed traits. The highest fresh and dry weight of shoots (3.85-4.87 g) and roots (1.46-23.2 g) and total chlorophyll (16.96 mg g-1) were observed in the control, while the highest protein (3.73 μg mg-1) and activity of superoxide dismutase (4.62 enzyme units g-1) and peroxidase (4.12 enzyme units g-1) in 75 mg l-1 sodium chloride treatment and the highest proline content (12/ 8 mg g-1) was observed in 75 mg l-1 potassium chloride treatment, also the lowest fresh and dry weight of aerial parts (2.12-3.08 g) and total chlorophyll (12.53 mg g-1) in 75 mg l-1 potassium chloride treatment and the lowest fresh and dry weight of roots (0.59-0.96 g) were obtained in 75 mg l-1 sodium chloride treatment, and the lowest content of proline (4.48 mg g-1), protein (2.48 μg mg-1) and the activities of superoxide dismutase (3.00 enzyme units g-1) and peroxidase (2.93 enzyme units g-1) were in the control.

According to the obtained results, sport turfgrass was able to tolerate stress conditions in 25 and 50 mg l-1 salt stress to some extent by increasing compounds such as proline, protein and antioxidant enzyme activity, but increasing the concentration of salts used, especially potassium chloride salt (75 mg l-1) had the greatest effect in reducing the vegetative traits and increasing the enzyme activity of sport turfgrass.

 Aromatic geranium is an ornamental perennial plant which its essential oil is used in perfumery, cosmetics, food and pharmaceutical industries. Water scarcity is one of the most important environmental stresses limiting plants’ growth and yield, which greatly impacts the morphophysiological, biochemical and enzymatic properties of plants and limits their development and survival. Using organic osmolytes such as proline and glycine-betaine increase the capacity and speed of photosynthesis, absorb ions such as magnesium and potassium, prevent the degradation of pigment-protein compounds, maintain plant pigments, strengthen the antioxidant system, and impact in inhibiting the adverse effects of water scarcity in plants. Thus, the aim of this study is to determine the best substance and effective concentration improving the quality and aromatic geraniums flowering under water scarcity stress.

Aromatic geranium cuttings were kept in commercial greenhouses with a temperature of about 17 to 20 Cᵒ, 60 to 70% relative humidity and light intensity of about 50 to 60 µm/m2S in Karaj city. Feeding with Hoagland solution was done once a week and in order to measure the soil moisture, the potting system was used, and irrigation was carried out based on the soil weight change according to the determined field capacity (FC). Foliar spraying with proline and glycine betaine (0, 50 and, 100 mg/l) was applied for a month after two weeks of placing the cuttings in pots and  24 hours of being at different levels of low scarcity stress (25, 50, 75 and, 100% field capacity), sequently. After completing the treatments, sampling and evaluating of traits such as fresh and dry weight of shoots and roots, petals anthocyanin, total leaf chlorophyll, proline and activity of superoxide dismutase and peroxidase enzymes were performed. The experiment was performed in 2019 as a factorial experiment in a completely randomized statistical design with two factors of applying water scarcity stress and spraying with proline and glycine-betaine and their interaction. Then, data were analyzed using SPSS, the means were compared with Duncan's multiple domain and graphs were drawn in Excel.

Data means comparison showed that the highest fresh and dry weight of shoots with 67.25 and 8.53 g and the highest fresh and dry weight of roots with 15.62 and 3.45 g were observed in 100% FC (control) and the lowest shoot fresh and dry weight with 44.76 and 4.45 g and the lowest fresh and dry weight of roots with 10.57 and 1.17 g, were in 25% FC treatment (without foliar application). Also, the highest and lowest petals anthocyanin with 2.8925 and 1.5775 mg/g FW and total leaf chlorophyll with 15.3735 and 11.1632 mg/g FW were in 100% FC (control) and 25% FC treatment (without foliar application). The highest and lowest proline levels were 3.84 and 1.67 mg/g of FW in 25% FC treatment (without foliar application) and 75% FC treatment + 100 mg/l of proline. The highest activity of superoxide dismutase and peroxidase enzymes with 2.97 and 16.52 UE/g of FW in 75% FC + glycine-betaine 100 mg/l treatment and the lowest with 1.12 and 12.93 UE/g FW in 25% FC treatment (without foliar application), was obtained.

The results demonstrate that the fresh and dry weight of shoots and roots decreased with increasing water scarcity stress, which this reduction was in 25% or more of field capacity and foliar application of plants with glycine betaine and proline inhibited the negative effects of stress at a concentration of 100 mg/l, both combinations were more visible. Petal anthocyanin and total leaf chlorophyll dropped with rising water scarcity stress and, treatment of plants with glycine betaine and proline had an effective role in ameliorating plant pigments. In addition, proline levels are increased by water scarcity stress. The highest enzyme activity was in 75% FC and with increasing water scarcity stress, enzyme activity reduced. Foliar application of plants with glycine betaine and 100 mg/l proline reduced the negative effect of water stress in 50 and 75% FC compared to 25% FC. Hence, according to the research results, the use of organic osmolytes such as glycine betaine and proline can be recommended to decrease the negative effects of water scarcity stress in ornamental plants.

As an essential micronutrients, iron (Fe) has significant effect on activity of antioxidant enzymes and thereby influences the crop tolerance to environmental stresses. On the other hand, environmental stresses, i.e. air pollution might modify Fe nutritional status of plants by affecting the activity of antioxidant enzymes. The purpose of this study was to investigate the changes in Fe concentration and activity of Fe-dependent antioxidant enzymes in leaves of Plantago major L.with distance from two major sources of air pollution in Shiraz city. Oil Refinery of Shiraz (ORS) and urban traffic of Imam Hossein square were selected as two major air pollutant sources in Shiraz city. Plant leaf samples were collected at different distances from the air pollutant sources. The concentrations of Fe, zinc (Zn), chlorophyll a and b, carotenoids, and activity of catalase and peroxidase in the leaves were measured. The results showed that Fe concentration in the plant leaves increased with distance from the ORS. Leaf Fe concentration was 34.86% and 44.73 % higher in the plants at the Rokn Abbad (12 km far from the ORS) town and Melli garden (20 km far from the ORS), respectively, in comparison with those plants close to the ORS. Chlorophyll concentration increased with distance from the ORS. Activity of catalase and peroxidase was increased by distance from the ORS. For the second route, traffic of Imam Hossein square, leaf Fe concentration significantly increased with distance from the source of pollution while no regular trend was found for the changes in chlorophyll concentration and catalase and peroxidase activity. Although many factors including soil properties may be effective in this regard, considering the similarities observed in the characteristics of the studied soils, it can be concluded that there was a close relationship between the Fe nutritional status of Plantago major L. and intensity of air pollution.

One of the properties of systemically acquired resistance in plants is their concomitance with the biochemical changes including enhancement of activities of defense-related enzymes. The leaf extract of Reynoutria sachalinensis (F. Schmidt) Nakai is known to be an effective compound for the control of a few plant diseases particularly powdery mildew of cucurbits (caused by fungal pathogen Podosphaera fusca), by inducing host defense responses. In the present investigation, the effects of this extract on some defense responses of cucumber plants were studied via in vivo tests. Changes of defense responses in the extract treated-cucumber plants, with or without pathogen inoculation, were studied and compared with those of non-treated control plants. Results indicated that specific activity of peroxidase increased significantly in treated tissues. Enhancement of enzyme activity showed the same patterns in both the pathogen inoculated- and non-inoculated-plants thus the pathogen attack did not affect the enzyme activity. Specific activity of phenylalanine ammonia-lyase in the non-inoculated extract treated-plants showed a transient fast increase during 24 hours after the treatment, whereas in the inoculated ones, it showed a permanent slow increase probably due to the interaction between extract treatment and pathogen attack. Phenolic content of extract treated-plant tissues, despite small fluctuations, did not show any definite pattern of changes.

Thirty genotypes of pistachio cultivars and related species were evaluated for genetic diversity using three polymorphic isozymes, i.e. Esterase, Peroxidase and Malate dehydrogenase. Young leaves of pistachio were crushed with extraction buffer containing: 20% sucrose, 0.01 M dithiothretiol, 2% polyethylene glycol, and 8% polyvenyl polypyrollidone. Samples were analyzed using isoelectric focussing on polyacrylamide gels containing 2% (W/V) ampholyte. All the three isozymes revealed high degrees of polymorphism in pistachio cultivars and related species. Maximum polymorphism was observed for Est. enzyme. A total of 19 bands in Est. and 28 bands in MDH were observed in a wide range of pH gradient however, in Per. there were 11 bands all of which located in a narrow range of pH gradient. Cluster analysis based on the three system enzymes revealed that all the 30 pistachio genotypes were in 8 main classes and 20 subclasses and the extent of genetic similarity reduced from cultivated varieties to species, which were finally classified in 3 groups. Sarakhs variety, a wild type of P. vera, was classified in a group between cultivated varieties and species.