| Summary: | 碩士 === 國立中興大學 === 森林學系所 === 101 === Dajashi National Forest had been established by way of a large-scale cultivation of Pinus taiwanensis in the 1960s. The fire line was built to prevent the potential risk of fire, but it was ineffective. Now the fire line is replaced by vegetative fire break, but it’s difficult to reforest. Therefore, the aim of this study was to improve the growth of fire-resistant tree species through inoculating arbuscular mycorrhizal fungi. This study investigated the soil chemical properties in fire line to identify the soil limiting factors, surveyed the status of mycorrhiza colonization and examined mycorrhizal species in fire line. To observe the benefit of mycorrhiza inoculation, seedlings of Gordonia axillaris were inoculated with mycorrhizal fungi spores isolated from fire line, then planted in fire line and greenhouse. The results showed that the soil was acidic, with pH value between 4.80 to 5.20. Soil exchangeable Aluminum was in high concentration between 287.02 to 671.89 μg g-1. Soil available phosphorus concentration was low between 0.01 to 3.11 μg g-1, which belonged to a phosphorus deficient range of plants. Total soil nitrogen (0.19-0.31%) and soil organic matter (4.38-7.84%) were moderate. Fire line vegetation were all mycorrhizaed, and the mycorrhizal species Acaulospora mellea, Ac. spinosa, Glomus. constrictum, Gl. mosseae and Paraglomus occultum were found. After Go. axillaris seedlings were inoculated with mycorrhiza, the death rate decreased. The accumulation of potassium and the glomalin-related soil protein were significantly higher in the field experiments of inoculation treatments, and sodium and aluminum accumulation were significant decreased. On the other hand, the Go. axillaris seedings height, leaf area, average leaf area, dry weight and tissue nutrients (N, P, K, Ca, Mg) of inoculation treatment in greenhouse experiments and the glomalin-related soil protein in soil were also significantly increased. Although the accumulation of sodium and aluminum were increased, plants grew well and healthly. Denaturing gradient gel electrophoresis profile of rRNA genes was present in arbuscular mycorrhizal fungi on roots of Go. axillaris seedings. This study indicated that the most important factor of plant growth in fire line was mycorrhiza, and the experiment proved that mycorrhiza inoculation could prevent seedlings from growth retardation or death due to stress.
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