Infecting Micromechanism Of Ectomycorrhizal Fungi To Picea Koraiensis

The studies on culture and physiological characteristics, the molecular biological classification and infection mechanism of two ectomycorrhizal fungi of Picea koraiensis were done by the methods of mycorrhizicology, mycology, molecular biology and technique of paraffin section. The results show as follow:To strain 025 growth, the optimum temperature is 25℃, optimum carbon source is glucose, optimum pH is 6.5～7.5; To strain 035 growth, the optimum temperature is 20℃, optimum carbon source is sucrose, optimum pH is 7.0. Both two strains grow best without nitrogen source, the nitrogen sources have certain inhibitory effects to the growth of 2 strains. The growth of strain 025 is faster than that of strain 035.The rDNA ITS sequence was amplified from strain 025 and 035 with the universal primers ITS 1 and ITS4 for the first time. Their ITS sequence length are 663bp and 662bp, the GenBank accession number is EF531717 and EF531716 respectively. By comparing with strains in GenBank, it is confirm that strain 025 is Cortinarius sp., the comparability between strain 025 and Cortinarius collinitus(AY083181) is 95%; strain 035 is Suillus sp., the comparability between strain 035 and Suillus granulatus (AJ272409) is 94%.The infection position and course of the different ectomycorrhizal fungi of Picea koraiensis are different, and the response of root cortex cells of Picea koraiensis seedlings is also different. The mycelium inner mantle of strain 035 firstly effect on the epidermis of root tip, and make them disappeared gradually; then enter into the cortex tissue through the gaps of disappeared cortex tissue, and forming Hartig net and then forming ectomycorrhiza gradually. The colour of root tip cells turn deeper, and the cellwall became thicker. The mycelium inner mantle of strain 025 adhere on the cortex of root, then enter into cortex cells through cortical pore and cortex gap, at same time the cortical pore and cortex gap disappear gradually, and then cortex disappear gradually. 2 ectomycorrhizal fungi can form mantle and Hartig net, but the mycelium can not enter into cells ofendoderm.The period of forming ectomycorrhiza is different for different ectomycorrhizal fungi. The faster the fungi grow, the shorter the ectomycorrhiza form. To the speed for ectomycorrhiza forming, strain 025 is far greater than strain 035. The thickness of mantle round the root rip has certain relation to seedling growth.