Study On Taxonomy Of Rhytismataceae And Biological Characteristics Of Lophodermium Pinastri

Rhytismataceae is an important part in the fungi. In this present thesis, the classification, morphology, ecology, geographical distributions, fruiting periods of some species of Rhytismataceae were systematically studied with the techniques of modern mycology and forest pathology.More than 160 specimens were examined, and 4 genera (Bifusella, Lophodermium, Rhytisma, Soleella) and 13 species were identified according to the taxonomic principles of Darker (1967), Cannon & Minter (1986), Johnston (1986). Among the taxa besides 9 species known for this country, which were neither systematically described nor only mentioned simply. There were still included 4 new species: Lophodermium crassichilum, L. rufolabium, Rhytisma rhododendri-simii, R. rugulosum. Keys were compiled for identification of all recognized species. Morphological characteristics were described and illustrated, and hosts, geographical distributions, fruiting period were recorded, and discussions were provided here. The host species included 7 families, which were Theaceae, Aceraceae, Ericaceae, Aquifoliaceae, Pinaceae, Taxodiaceae, Gleicheniaceae. New species' type specimens were deposited in the Forest Protection Laboratory of Anhui Agricultural University (AAUFP), Hefei, China.A pathogen caused needle cast of pine, which was widely spreaded in Hefei city, was identified to be Lophodermium pinastri. The effects of nutrition, light, temperature and pH values on mycelia growth of L. pinastri were studied, and the mycelia growth inhibition rates of 3 kinds of fungicides were measured. The results showed that: there was small difference in mycelia growth on 4 kinds of culture media. The optimum pH value was 5.6-6.4. The difference of light influence on the mycelia growth was not remarkable. The mycelium growth range of temperature and the optimum temperature were 2-35℃ and 24℃ respectively. The toxicity of fungicides revealed that 50% carbendazim, 70% thiophanate-mehyl and 75% chlorothalonil all could inhibit mycelia growth and their fungicides EC50 were 0.1100μg/ml, 0.2649μg/ml and 1.7920μg/ml respectively. Above all, the most effective fungicide was 50% carbendazim.The effects of nutrition, pH values, light and UV on ascospores' germination of L. pinastri were also studied. The results were reported as follows: the rate of ascospores germination was the highest in 25% decoction of pine-needle, and the following is 2% glucose solution, 20% potato decoction, 2% sucrose solution and sterile water. The ascospores could germinate within the range of pH3.0-8.0, and could hardly germinate in pH9.0. The rate of germination was the highest in pH5.0 and the acid condition was beneficial to their germination. The effect of light on ascospore germination was not remarkable. The optimum temperature for ascospore germination was 25℃, and ascospores were inhibited to germinate by ultraviolet radiation and comparing with contrast group. The rate of germination of ascospores was reduced notably and ascospores were dealt with ultraviolet radiation for more than 10 minutes could not germinate.