Vesicular-arbuscular mycorrhizal symbioses in some plants and their relationship with soil factors and seasons. Mahmood Ghorbani*, Jalil Khara and Nasser Abbaspour

Mycorrhizal association in seven plants grown in Arasbaran forest located in the north west of Iran was investigated. The soil samples were collected from the plants rhizosphere. Physico-chemical properties of rhizosphere soils like soil texture, pH, EC and some extractable nutrients such as N, P and K were recorded. The number of spores in rhizosphere and percentage of root mycorrhizal colonization were found. Soil physico-chemical analyses were done on August while spore number and root colonization were studied in May and August. All the data collected in this research were analyzed by the statistical software, SPSS. Results showed that different plant species colonized differently by VAM fungi, and spore number and root mycorrhizal colonization increased through the time from May to August. Among the physicochemical factors, soil N content had high correlation with root colonization and soil extractable P had high correlation with soil spore number. pH had a high negative correlation with spore number. Among the plant species, Stachys pubescens showed the most VAM fungi root colonization and Cruciata laevipes rhizosphere soil showed the highest spore number.