جستجوی مقالات مرتبط با کلیدواژه « symbiosis » در نشریات گروه « محیط زیست »

Arbuscular mycorrhizal fungi (AMF-phylum Glomeromycota) are one of the most important beneficial soil microorganisms that form a mutualistic symbiotic relationship with the roots of more than 80% of terrestrial plant species. These fungi improve the mineral nutrients (especially phosphorus) and water uptake and enhance plant tolerance to various biotic and abiotic stresses such as pathogens, salinity, drought and heavy metals contamination. Hence, they play a key role in the establishment of plant communities in different ecosystems. The present study aimed to identify AMF species associated with different plants roots based on morphological characteristics, comparison of spore’s population and determine the percentage of root colonization in the Kolah'ghazi protected region in Isfahan Province.

At first, 12 plants were selected from the predominant plants that are AMF hosts. The sampling was conducted from a depth of 5 to 30 cm in the rhizosphere of each plant and the soil and root samples were collected. Roots fragments were stained in lactoglycerol blue and the percentage of root colonization was calculated. AMF spores were extracted from each air-dried soil sample (300-500 g) by wet sieving and centrifugation in sugar solution methods. Also, spore populations were determined in a gram of soil with three replications. Then, the isolated spores were identified based on morphological characteristics such as color, shape, size, wall structure, hyphal attachment, etc.

Microscopic observations indicated that all the sampled plant roots were colonized by AMF. The percentage of AMF colonization ranged from 9-92% among plants species and the highest and lowest of it were observed in Thymus vulgaris and Alyssum homolocarpum plants, respectively. The highest spore density was in the rhizosphere of the Th. vulgaris and the lowest was related to Lepidium draba. The statistical analysis showed that there is a positive correlation between the percentage of mycorrhizal colonization and the number of spores in most plants. Based on morphological criteria, 12 species of AMF belonging to 8 genera Claroidoglomus (C. etunicatum and C. luteum), Funneliformis (F. caesaris and F. geosporum), Glomus (G. ambisporum), Rhizophagus (Rh. aggregatum and Rh. fasciculatus), Septoglomus (Se. africanum, Se. constrictum and Se. deserticola), Entrophospora (E. infrequens), Gigaspora (Gi. gigantea) and Scutellospora (Scutellospora sp.) were identified. Se. africanum is new for mycoflora from Iran and other identified species have previously been reported from different regions and crops.

Due to the importance of AMF, identification and reproduction of these fungi for exploiting their potential in regenerate arid areas, especially protected areas, can be necessary. However, further research is needed to more accurately identify AM species.

Nowadays, heavy metal pollution has become a serious environmental problem. To protect the environment, one of the effective and low-cost methods is phytoremediation. Phytoremediation is the use of plants to remove, reduce and stabilize pollutants. In this regard, the use of fungi that symbiosis with plants, can increase the efficiency of phytoremediation, reduce the time required to remove contamination, and develop its application.

This experiment was performed in order to investigate the traffic and symbiosis interaction’s effects on lead and cadmium accumulation in rosemary (Rosmarinus officinalis L.). The experiment donen in a randomized complete block design (RCBD) with three replications and three factors as factorial. The first factor includes mycorrhiza symbiosis (control and inoculation), the second factor was traffic (Control, 120, 300, 600, 950, 1200, 1800, 2400, 3000, 3600, and 4200 cars per hour) and the third factor was the type of pot (Controls and pots where the soil surface is covered except at the place of seedlings) with three replications in 2019-2020 in Shiraz metropolis. In the experiment some properties were investigated such as root weight, soil cadmium, shoot cadmium, root cadmium, stem length, main root length, plant dry weight, root lead, cadmium, and lead transfer factors.

The results of mean comparisons showed that inoculation of plants with mycorrhizal fungi )Glomus mossea (had higher lead content of root tissue than shoots and soil in 4200 cars per hour compared to the control. Symbiosis with mycorrhiza fungi increased root weight and plant dry weight, stem length, and main root length compared to the control by 23.93, 18.97, 0.82 and 30.87% in 4200 car traffic per hour, respectively. The results also showed that the treatment of closed pots and inoculation of mycorrhizal fungi increased the growth parameters and decreased cadmium and lead.

The reduction of cadmium and lead concentrations in the inoculated rosemary with Glomus mosses indicates that Rosmarinus officinalis L. can grow in soils contaminated with cadmium and lead. Also, the symbiosis of mycorrhizae increases th ability of rosemary.

One of the ways to reduce soil pollution is the use of plants, which is more effective than other methods due to its simplicity, cheapness and compatibility with the environment. Mycorrhizal fungi symbiotic with plants can further reduce pollution by changing and modifying plant physiological processes.

In order to investigate the effect of arbuscular mycorrhizal fungus (Glomus muse species) on the phytoremediation potential of coriander, rosemary and ornamental cabbage in soils contaminated with lead, a completely randomized and factorial experiment with 3 types of plants (coriander, ornamental cabbage) And rosemary) had 6 levels of lead (0, 25, 50, 100, 200 and 400 mg of lead per kg of soil) and two levels of mycorrhizal arbuscular fungus (inoculation and non-inoculation) in 2017 in one of Abdanan greenhouses were done.

The results showed that with increasing soil lead levels, the concentration of lead in the roots and shoots of the plant increased. Arbuscular mycorrhiza increased the concentration of lead in the roots and shoots of rosemary. Mycorrhizal fungi also increased the concentration of lead in the aerial parts of ornamental cabbage but decreased the concentration of root lead. The highest concentration of shoot shoot was observed from rosemary plant and inoculated with mycorrhizal fungus and the lowest concentration of shoot shoot was observed from rosemary plant and not inoculated with mycorrhiza. The highest lead transfer factor was 5.8 from ornamental cabbage plant inoculated with mycorrhizal fungus and the lowest lead transfer factor was 0.7 from mycorrhizal plant inoculated with mycorrhiza.

The use of mycorrhizal arbuscular fungus increased the concentration of lead in the ornamental cabbage, which is used in phytoremediation of contaminated soils.

The lack of a grazing system management program along with other natural and human factors in the country has led to the degradation of rangelands to a large extent. From a new perspective, the lack of grazing management, as an indirect consequence, but with a key role, can have negative effects on useful soil microorganisms, in particular, plant symbiosis with arbuscular mycorrhizal fungi. In this case, due to the sever imbalance between plant and fungus, the reclamation of rangelands with the help of symbiotic soil fungi will be difficult. To investigate the effects of grazing management on AMF symbiosis with S. laricina in three sites of heavy grazing, light grazing, and no grazing, the root and soil were completely randomly sampled around the rhizosphere. The mean of root colonization percentage and soil spores frequency, after assurance of homogeneity of variance and normal mean of data, were compared with the Duncan's analysis of variance at 95% confidence level. Early grazing and the lack of grazing systems management are among the factors that greatly reduce the fungus symbiosis with the roots of plants. Over time, the loss of this important ecosystem chain along with other factors, such as climate change and mismanagement of natural areas, has led to the decreased number of Salsola individuals. This results in changes in species composition and abundance as well as the presence of unpalatable and invasive species, which ultimately leads to the rangeland degradation.