Elham Nouri; Alireza Moshki; Mohammad Matinizadeh; Ali Asghar Zolfaghari; Saeede Rajaei
Volume 27, Issue 4 , December 2020, , Pages 631-671
Abstract
Due to their various roles in the plants’ life, the Arbuscular mycorrhizal fungi (AMF) has been studied from various aspects. In Iran, study on this type of fungi is still at its infancy. Also, the variety of plant species and populations in Iran necessitates a more in-depth analysis compared to ...
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Due to their various roles in the plants’ life, the Arbuscular mycorrhizal fungi (AMF) has been studied from various aspects. In Iran, study on this type of fungi is still at its infancy. Also, the variety of plant species and populations in Iran necessitates a more in-depth analysis compared to other countries in the world. The present study aimed at investigation of the effects of grazing intensity on the diversity and populations of these microorganisms that are symbiotic with the plants and also determining the factors affecting the soil. Three rangelands were considered with three different grazing pressures: no grazing pressure, managed grazing and heavy grazing. Following the sampling of the soil around the rhizosphere of the dominant plant species, the samples were transferred to the laboratory to be analyzed. The results of this study revealed the significant differences in the diversity of AMF species in different sites, and the highest frequency percentage was related to the Septoglomusconstrictum species identified in the heavy grazing region(42.2%).Also, grazing caused changes in the mycorrhizal symbiosis percentage and these factors had a direct correlation, and this could be an evidence of the reduced diversity of AMF, because despite of the existence of spores in the soil, each plant species can only correlate with specific species of AMF. It can be said that appropriate grazing cannot have a negative effect on the population and diversity of AMF, because species diversity indices in a managed grazing region are in a stable state; and, by the proper management of the grazing system and preventing the premature or excessive grazing, its harmful effects can be prevented.
Mohammad Matinizadeh; Mahmoud Gudarzi
Volume 20, Issue 1 , June 2013, , Pages 213-225
Abstract
Fire can severely affect vegetation and soil and prevent different cycles of ecosystems. Enzymes quantities are sensitive indices for soil quality, and the changes in their activity can affect the ability of ecosystem and alter nutrient uptake by plants. This investigation was carried out in Kordan rangeland ...
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Fire can severely affect vegetation and soil and prevent different cycles of ecosystems. Enzymes quantities are sensitive indices for soil quality, and the changes in their activity can affect the ability of ecosystem and alter nutrient uptake by plants. This investigation was carried out in Kordan rangeland in spring and autumn for two years. Soil was sampled from 0-20 cm depth. Three enzymes including acid phosphatase, alkaline phosphatase and dehydrogenase were assessed by reaction with substrate. Our results showed that the activities of all studied enzymes were significantly higher in soils in September at both areas. However, this difference was not high for alkaline phosphatase. Two years after fire, the activity of all studied enzymes was higher at control site. The reasons for this decrease may be due to the destruction of enzymatic system and increasing inorganic phosphate because of fire. Three years after fire, the activity of enzymes increased and for alkaline phosphatase and dehydrogenase was more than control site. These enzymes are considered as biological indices for soil microorganisms therefore, it can be expected that its increase indicates increasing microbial biomass in fire area.