塔塔加森林硬木區與草原區土壤微生物族群之季節性變化

Comparative Study on the Seasonal Variation of Microbial Populations in the Hardwood and Grassland of Tatachia Forest Soils, Taiwan

安妮塔(Anita Ravindran)

指導教授 ： 楊盛行

國立臺灣大學/生命科學院/微生物與生化學研究所/碩士(2006年)

https://doi.org/10.6342/NTU.2006.01752

摘要

微生物於土壤有機質礦化、土壤氮與碳循環中扮演重要角色，並為植物攝取土壤氮及碳之強競爭者，故微生物動力學為控制森林生產力之重要因子。目前對於微生物動力學與植物之關係之了解尚十分缺乏，此部份研究可以闡明林地環境對微生物族群之重大影響。本研究分別測定2004~2006年間硬木區及草原區之土壤、氣溫、日照等不同環境條件，水分含量、pH值、總有機碳、總氮、C/N比等土壤性質，總菌、放線菌、真菌、纖維素分解菌、溶磷菌和固氮菌等微生物含量，對其季節性變化進行探討，並針對由較老的針葉樹種雲杉及鐵杉組成之高海拔森林，與低海拔較年輕之人造林比較此二林相之異同。故本研究將提供更多關於環境條件、土壤性質以及微生物相之重要資訊，此外，本研究並自土壤中分離DNA，對其進行定序，並試圖得到更多資訊。土壤性質之測定結果顯示，雲杉區之水分含量為 37.19-58.41%、pH 值介於 4.02-4.65、總有機碳含量為 7.21-24.48%、總氮含量為 0.45-1.47%、C/N 比為 12.49-23.59；鐵杉區之水分含量為 42.08-68.06%、pH值為 3.43-4.18、有機碳含量為 10.12-26.30%、總氮含量為 0.35-1.57%、C/N 比為 15.35-34.61；草原區之水分含量為 30.54-49.14%、pH值為 3.99-4.42、總有機碳含量為 4.71-20.95%、總氮含量為 0.19-0.87%、C/N比為 18.02-31.46。在微生物生態方面，雲杉區每克乾重土壤含總菌量為 3.53×106-4.95×107 CFU、放線菌量為 6.53×103-4.29×104 CFU、真菌量為 1.14×105-6.20×105 CFU、纖維素分解菌量為 1.03×106-4.10×106 CFU、固氮菌量為 8.77×104-7.50×104 CFU、溶磷菌量為 2.29×104-8.57×104 CFU、微生物生質碳 459.77-1318.21 µg-C、微生物生質氮 61.03-194.58 µg-N；鐵杉區每克乾重土壤含總菌量為 2.97×106-5.63×107 CFU、放線菌量 2.10×103-4.23×104 CFU、真菌量 8.65×104-5.71×105 CFU、纖維素分解菌量 1.35×106-4.11×106 CFU、固氮菌量 7.29×104-7.36×104 CFU、溶磷菌量 2.39×104-9.61×104 CFU、微生物生質碳 364.11-1364.52 µg-C、微生物生質碳 44.25-173.49 µg-N；草原區每克乾重土壤含總菌量為 2.15×106-2.66×107 CFU、放線菌量 8.58×103-3.98×104 CFU、真菌量 1.33×105-4.67×105 CFU、纖維素分解菌量 8.37×105-4.01×106 CFU、固氮菌量 6.44×104-8.67×105 CFU、溶磷菌量 2.33×104-7.60×104 CFU、微生物生質碳 288.57-1070.44 µg-C、微生物生質氮 36.32-151.09 µg-N；硬木區土壤之水分含量較草原區為高，且其總菌、纖維素分解菌量以及固氮菌量亦相對較高。另外，在秋天、冬天、春天、夏天之季節，其DNA 產率分別為9.534-30.098、9.534- 27.785、 l9.645-25.291及 9.554-24.39 µg g-1 dry soil，而自土壤中分離DNA並藉由PCR-DGGE技術以比較指紋圖譜，瞭解微生物族群差異。

關鍵字

微生物生質碳 ； 微生物生質氮 ； 微生物族群

並列摘要

Microbial dynamics are important factors in controlling forest productivity as microorganisms involve in mineralization of soil organic matter, soil N and C cycle and are strong competitors with plants for soil N and C. They are less studied especially in relation to vegetation, which can produce strong effects on the microbial community by affecting the forest floor environment. In this study, environmental conditions such as soil and air temperatures, light intensity, soil properties of moisture content, pH, total organic carbon, total nitrogen and C/N ratio and microbial populations of total counts, actinomycetes, fungi, cellulolytic microbes, phosphate-solubilizing microbes and nitrogen-fixing microbes were measured during the year 2004-2006. The seasonal variations of soil properties and microbial populations in hardwood and grassland forest were studied and compared. The hardwood forest consists of spruce and hemlock, which is composed of old coniferous trees which were compared with grassland consisting of young plantation. A comparative study is made to find and establish differences between the two vegetations. This study will give more vital information regarding the environmental conditions, soil properties and microbiological information. In addition we have isolated DNA from the soils, and sequenced it and tried to give more information. The spruce vegetation, had moisture content 37.19-58.41%, pH 4.02-4.65, total organic carbon 7.21-24.48%, total nitrogen 0.45-1.47%, C/N ratio 12.49-23.59. The hemlock vegetation had moisture content 42.08-68.06%, pH 3.43-4.18, total organic carbon 10.12-26.30%, total nitrogen 0.35-1.57%, C/N ratio 15.35-34.61. The grassland vegetation had moisture content 30.54-49.14%, pH 3.99-4.42, total organic carbon 4.71-20.95%, total nitrogen 0.19-0.87%, and C/N ratio 18.02-31.46. Each gram of spruce soil had total viable count of 3.53×106 - 4.95×107 CFU, actinomycetes 6.53×103 - 4.29×104 CFU, fungi 1.14×105 - 6.20×105 CFU, cellulolytic microbes 1.03×106 - 4.10×106 CFU, phosphate-solubilizing microbes 2.29×104 - 8.57×104 CFU, nitrogen-fixing microbes 8.77×104 -7.50×104 CFU, biomass carbon 459.77-1318.21 µg-C and biomass nitrogen 61.03-194.58 µg-N. Each gram of hemlock soil had total viable count of 2.97×106 - 5.63×107 CFU, actinomycetes 2.10×103 - 4.23×104 CFU, fungi 8.65×104 - 5.71×105 CFU, cellulolytic microbes 1.35×106 - 4.11×106 CFU, phosphate-solubilizing microbes 2.39×104 - 9.61×104 CFU, nitrogen-fixing microbes 7.29×104 - 7.36×104 CFU, biomass carbon 364.11-1364.52 µg-C and biomass nitrogen 44.25-173.49 µg-N. Each gram of grassland soil had total viable count of 2.15×106 - 2.66×107 CFU, actinomycetes 8.58×103 - 3.98×104 CFU, fungi 1.33×105 - 4.67×105 CFU, cellulolytic microbes 8.37×105 - 4.01×106 CFU, phosphate-solubilizing microbes 2.33×104 - 7.60×104 CFU, nitrogen-fixing microbes 6.44×104 - 8.67×105 CFU, biomass carbon 288.57-1070.44 µg-C and biomass nitrogen 36.32-151.09 µg-N. Moisture content of hardwood forest soil is higher than grassland soil. We noted comparatively higher total microbes, cellulolytic microbes and nitrogen-fixing bacteria in hardwood forest when compared with grassland. The yield of DNA in autumn, winter, spring and summer season was from 9.534 to 30.098, 9.534 to 27.785, l9.645 to 25.291 and 9.554-24.39 µg g-1 dry soil, respectively. Soil DNA based PCR–DGGE was used for visually comparing the fingerprints profiles to determine the microbial community differences.

並列關鍵字

Microbial biomass carbon ； microbial biomass nitrogen ； microbial community

參考文獻

Anderson, T.H., Domsch, K.H., 1993. The metabolic quotient for CO2 (qCO2) as a specific activity parameter to assess the effects of environmental conditions, such as pH, on the microbial biomass of forest soils. Soil Biology and Biochemistry, 25: 393-395.

Andersson, S., Ingvar Nilsson, S., 2001. Influence of pH and temperature on microbial activity, substrate availability of soil-solution bacteria and leaching of dissolved organic carbon in a mor humus. Soil Biology and Biochemistry, 33: 1181-1191.

Ashton, E.C., Macintosh, D.J. 2002. Preliminary assessment of the plant diversity and community ecology of the Sematan mangrove forest, Sarawak, Malaysia, Forest Ecology Management, 166: 111-129.

Baath, E., 1996. Adaptation of soil bacterial communities to prevailing pH in different soils. FEMS Microbiology Ecology, 19: 227-237.

Baath, E., 1998. Growth rates of bacterial communities in soils at varying pH: a comparison of the thymidine and leucine incorporation techniques. Microbial Ecology, 36: 316-327.