Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/27970
標題: 關刀溪森林生態系協生性固氮菌對碳源利用之多樣性
Diversity of carbon source utilization of root associative N----2-fixing bacteria in Kuandaushi forest ecosystem
作者: 洪銘杰
M.J.Horne
關鍵字: associative nitrogen-fixing bacteria;協生性固氮;biodiversity;carbon source utilization;forest ecosystem;生物多樣性;碳源代謝;森林生態系
出版社: 土壤環境科學系
摘要: 
The purpose of this study was to investigate the diversity of root associative N----2-fixing bacteria in Kuandaushi forest ecosystem which is in the middle part of Taiwan . Carbon source utilization was used to evaluate the functional biodiversity of the microbes in this study . N----2-fixing bacteria isolated from Dicranopteris taiwanesis root , sampled from landslide site , burned site , natural forest and Cunninghamia lanceolata plantation were inoculated into Biolog microplates , which contain 95 carbon sources, to investigate the diversity of N----2-fixing bacteria . In addition , at the burned site and unburned site , associative N----2-fixing bacteria were isolated from D. taiwanesis , Nephrolepis auriculata , Pteridium aquilium , and Dicranopteris warburgii , respectively to test their diversity . The results show that rhizosphere N---2-fixing bacterial community was primarily dominated by plant species rather than environmental variation caused by fire . The associative N---2-fixing bacteria isolated from D. taiwanesis show a significant low similarity between burned and unburned area . However , the carbon source utilization of the N----2-fixing bacteria associated with N. auriculata , P. aquilium , D. taiwanesis were much similar between isolates obtained from burned site and unburned site.

關刀溪森林生態系為台灣中部極具代表性之森林,此生態區中固氮菌會隨著不同的環境(如林相、火燒干擾等)有不同的固氮活性。本研究之目的,欲探討該生態區中,不同的環境對植物協生性固氮菌多樣性的影響,以及火燒前後,植物協生性固氮菌有何變化。微生物的功能多樣性包括其對不同碳源利用上的歧異,亦即對多種碳源利用的豐富度及均勻度。Biolog 菌種鑑定系統提供了一組可同時測試微生物對95種不同碳源代謝的裝置,本實驗以此系統來探討協生性固氮菌的多樣性。
生芽鐵角蕨廣為分佈在此生態區中,其協生性固氮菌在不同的林相、坡度、火燒干擾等環境中,顯示了不同的碳源代謝多樣性。碳源代謝之多樣性愈高表示微生物可利用碳源的豐富度及代謝速率較高。在海拔愈低的樣區,其碳源代謝多樣性愈高;斜坡的環境中,固氮菌對碳源的利用率愈高;火燒區相較於未火燒之對照區,固氮菌對碳源代謝的多樣性也提高了。雖然不同的環境造成生芽鐵角蕨協生固氮菌在生理上不同的反應,但是這些固氮菌在菌種相似度上仍表現出很高的同源性。這結果顯示了植物本身對其協生性固氮菌的主導性大過於環境,僅管在不同環境中,植物選擇其協生性固氮菌族群未受很大影響。在火燒地及其對照區選取四種不同植物做試驗,也得到相同的結果;而不同的植物即使在同一環境中,其協生性固氮菌之間對碳源的利用性仍有顯著差異。由實驗中也發現,同樣的火燒干擾對不同的植物影響程度不同;而協生固氮菌對碳源代謝多樣性高的植物並非樣區中之優勢族群,顯然固氮菌對碳源的利用性並未與植群演替之優勢有何相關。
URI: http://hdl.handle.net/11455/27970
Appears in Collections:土壤環境科學系

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