فهرست مطالب ساره مرادی بهبهانی

Riparian forests are one of the unique forest ecosystems, but, there are little information available about these forest ecosystems in the Iran. These forests have an important role in riparian ecosystem protection, but they are in danger. Populus euphratica is one the most common tree species in these ecosystems and is a native species of arid and semiarid sites that spread out in most part of the Iran. Regarding to lack of data about symbiosis of arbuscular mycorrhizal fungi and P. euphratica, this study was done to study of AMF symbiosis with P. euphratica and the effect of distance from river bank on root colonization and spore density. Furthermore, correlation between soil physiochemical properties, root colonization and spore density were investigated to determine the most effective parameters on this symbiosis.
The Maroon riparian forest width was divided to three distances with 200 meter interval. Site one, two and three were located beside water, 200 and 400 meters away from river, respectively. Then, 10 soil samples belonged to P. euphratica rhizosphere were collected in each site. Also, for each selected tree, root samples were collected, and root length colonization and spore density were determined. Furthermore, soil physiochemical properties of each studied distance were determined.
The result indicated that the least root length colonization belonged to the distance two and significantly was lower than the other two studied distances. This result might be because of human activity in this distance that could have negative effect on root length colonization. Moreover, although no significant difference was observed for spore density in studied distance, but the highest value of spore density belonged to the distance three. Soil phosphorous, sand and clay were significantly different between studied distances. While, the other studied soil physiochemical parameters showed no significant differences in studied distances. Furthermore, no correlation was observed between root length colonization and spore density. Significant correlation was observed between soil clay, silt and phosphorus. While, root length colonization and spore density showed no significant correlation with studied soil physicochemical parameters.
Regarding to the high level of root length colonization and spore density in P. euphratica rhizosphere we could say that there is high level of symbiosis between P. euphratica and mycorrhizal fungi. Using this symbiosis could be an effective way in protection and expansion of P. euphratica afforestation. Moreover, distance from river bank is an effective parameter on mycorrhizal fungi symbiosis in riparian forest.

Salt cedar is widely spread out in most part of the country but there is lack of information about its symbiosis with arbuscular mycorrhizal fungi. Then, the main objective of this study was to evaluate the symbiosis of AMF with salt cedar and its affectability by distance from river and soil physiochemical properties. For this purpose, riparian Maroon forest width was divided to three locations including riverside area, intermediate area and the area far from river with 200-hundred-meter interval. In each site 10 salt cedars were randomly selected and soil plus hair root samples were gathered from the salt cedar rhizosphere. Our result indicated that root colonization and spore density in the intermediate distance had the lowest and highest values, respectively. These values were significantly different compared to the other two sites. The average root colonization percent in the riverside area, intermediate area and the area far from river sites were 82.37, 73.77 and 80.17, respectively. While the average spore density in the riverside area, intermediate area and the area far from river were 189, 245.5 and 188.8 in five gram soils, respectively. Root colonization had significant positive correlation with soil potassium while spore density had significant correlation with studied soil physiochemical properties. Also, soil nitrogen, organic carbon, potassium and clay showed 52.6, 51.19, 50 and 23.4% decreasing trend from the riverside area to the area far from river. Regarding this research results, salt cedar showed high level of symbiosis with arbuscular mycorrhizal fungi but this symbiosis could be affected by distance from river in riparian forest.