Abstract:

Endophytic fungi were isolated from Sphaerophysa salsula samples from Alashan of Inner Mongolia to investigate whether endophytic fungi exist in this plant and to assess the diversity and distribution of endophytic fungi. The optimal method for sterilization of plant materials surface with 75% ethanol and 2%NaClO was determined by the general method of endophytic fungus’ isolation and purification, species and genus of endophytic fungus was identified by the traditional morphology and molecular biology. It was found that 75% enthanol for 30 s, 2% NaClO for 3.5 min. and 75% enthanol for 50 s, 2% NaClO for 4 min. were more suitable for leaf and seed sterilization of Sphaerophysa salsula, respectively. Under the optimal surface sterilization conditions, leaf had a maximum isolation rates （41.67%）, followed with seed （37.14%）; and the species and the quantity ratio （38.75%）of endophytic fungi isolated from seed was the highest, followed with stem （20.00%）. Eighty strains of endophytic fungi were isolated from 4 different tissues of Sphaerophysa salsula, which belonged to 10 genera, 6 families, 5 orders and 4 classes. Alternaria sp and Fusarium sp were the dominant species in this plant with the relative frequency 53.75% and 21.25%, respectively. There was an obviously difference in quantity, species and distribution of the endophytic fungi between different parts of Sphaerophysa salsula. Seed and leaf were the most vulnerable to infection and colonization by the endophytic fungi and the diversity was maximum in seed of Sphaerophysa salsula.

Key words: Sphaerophysa salsula, endophytic fungi, isolation and identification, rDNA-ITS, diversity