臺灣中部高侵蝕惡地生物土殼的藻類歧異度與水份逆境之生理效應

Biodiversity and physiological responses to water stress of soil algae in biological soil crusts in highly eroded badlands of central Taiwan

林敬舒(Ching-Su Lin)

指導教授 ： 吳俊宗

國立臺灣大學/生命科學院/生態學與演化生物學研究所/博士(2014年)

https://doi.org/10.6342/NTU.2014.02650

摘要

本研究對生長在中臺灣著名惡地，包括火炎山、大坑與大肚等地區的土壤藻類進行歧異度、豐富度、親緣演化與水份逆境等調查和分析，並同時探討建立生物土殼(BSCs)的可能性。研究結果顯示，火炎山和大肚的土壤藻主要由綠藻組成，優勢藻屬包括Bracteacoccus、Coccomyxa、Klebsormidium和Koliella等四屬；大坑則以藍綠菌為主，以Leptolyngbya數量最優勢。土壤藻之群集結構顯著受到環境因子(特別是溼度)、土壤質地和植被發展等影響。由16S rDNA與葉綠體23S rRNA分析顯示，生活於此類環境中土壤藻間之親緣關係頗為複雜且歧異。本研究利用添加聚乙二醇(PEG)來研究土壤藻對水份逆境的耐受生理，發現在水份逆境下細胞內之脯氨酸、丙二醛(MDA)、色素、抗氧化酵素(如SOD)等的含量會顯著提升。其中，脯氨酸、SOD和類胡蘿蔔素含量的變化量可反映物種的抗水份逆境能力。此外，本研究嘗試利用Leptolyngbya boryana來建立BSCs，發現在建立過程中，隨著土壤生物量的增加，許多理化參數測值都顯著增高。建立過程可區分為初始期、成熟期、延展期、抗衡期和衰退期等5個時期，其中以前2-3個月最為關鍵。溼度可能為控制BSCs發展的最重要因子。在適當的環境下，約6個月即可見BSCs有藍綠菌、綠藻、矽藻，及真菌和蘚苔類等之拓殖。此外，人為刮除山壁上BSCs後，約經1年時間即可恢復至近似刮除前的初始狀況。綜合研究結果顯示，L. boryana具有分佈廣泛、生長快、培養容易、絲狀藻體易糾纏、忍受逆境能力強等優勢，可能為要進行BSCs建立、生態恢復等工法時的極佳先趨物種。

關鍵字

生物土殼 ； 土壤藻 ； 歧異度 ； 水份逆境 ； 惡地 ； 生態復育

並列摘要

This study was aimed to characterize the diversity, abundance, phylogeny, and stress physiology of indigenous soil algae at highly eroded badlands, including Dadu, Dakeng, and Hoyen Mountain situated in mid-Taiwan and to elucidate the feasibility of establishing biological soil crusts (BSCs). At Hoyen Mountain and Dadu, dominant soil algae were of chlorophytes including those genera of Bracteacoccus, Coccomyxa, Klebsormidium, and Koliella, while at Dakeng of cyanobacteria such as Leptolyngbya. The distribution of soil algae exhibited a strong dependency on environmental variables such as soil moisture, soil texture, and the vegetation type. For phylogenic analysis of soil algae, both the 16S rDNA and plastid 23S rRNA were used. The results showed that these algae belonged to an evolution complex. To study the physiology of water stress in soil algae, polyethylene glycol (PEG) was used as an inducer. As a response to PEG treatment, the intracellular proline levels were elevated, which was associated with increases in malondialdehye (MDA), pigment contents, and activities of antioxidant enzymes such as superoxide dismutase (SOD). As a result, the tolerance to water stress could be indicated by the intracellular levels of proline, SOD, and caroteniods. Moreover, to test the establishment of BSCs, L. boryana was used. The development of BSCs resulted from this organism would improve remarkably the biological and physiso-chemical properties of the soil environment. The establishment of BSCs could be differentiated into five stages, namely initial, mature, extended, contended, and declined. The time of establishment varied with environmental factors at the habitat. It was suggested that filamentous L. boryana may be a suitable pioneer organism for BSCs establishment and restoration of the disturbed environments.

並列關鍵字

Badlands ； Biological soil crusts ； Biodiversity ； Water stress ； Establishment ； Soil algae

參考文獻

王俊閔、邱清安、曾彥學、曾喜育、呂金誠。2010。臺中大坑地區植群調查研究。林業研究季刊32：7-22。

台中縣市山坡地土壤調查報告。1985。臺灣省政府農林廳山地農牧局編印。

林俊全。2011。苗栗三義火炎山的沖蝕特性。地景保育通訊 32：29-34。

張德鑫、梁庭維。2011。紅壤土之入滲試驗及參數推估。農業工程學報 57：1-12。

蔡宜峰、黃祥慶、黃山內。1990。中部地區紅壤改良之綜合研究。臺中區農業改良場研究彙報 29：49-60。