Isolation and Identification of Fungi Associated with Chestnut-Leaved Oak (Quercus castaneifolia) Seed in Shast-Kalate Forest of Gorgan

Chestnut-leaved Oak (Quercus castaneifolia) is one of the most important industrial species of the northern forests of Iran. Regeneration of this valuable species is limited due to several problems such us pests and the fungal diseases. In order to isolate and identify the fungi associated with Oak seed, sampling was carried out during 2007 in Shast-kalate forest at Gorgan. Collected seeds were separated into two section: outer section of seed (crust) and inside seed section (endosperm) and then their surface was sterilized with 0.5% sodium hypochlorite. Each section of seed was separately tissue cultured on potato dextrose agar media in 4 replicates. After sub-culture and providing fungi pure cultures, various species isolated and identified by spores characteristics, their size and colour, including: Aspergillus flavus, A. niger, Curvularia affinis, Trichoderma harzianum, Trichothecium roseum, Eurotium rubrum, Penicillium implicatum, and Diplodia sp. The fungi, E. rubrum, T. roseum, T. harzianum, and Diplodia sp. were observed only in the outer seed section by 35%, 41%, 7% and 23% frequency, respectively. The fungus C. affinis observed only inside seed section by 39 percent frequency. The fungi, A. flavus, A. niger, and P. implicatum were observed in the both sections of the seeds. The highest frequency of fungus related to P. implicatum by 74 percent frequency within seed section. The result indicate higher frequency and diversity of the fungi in the outer section of the seeds than within the seeds. More over, there is always a saprophyte fungus on the acorn seeds, during several isolation. This is the first report on fungi associated with Oak seed in Iran.