| Abstract: | 物種功能性狀的權衡 (trade-off) 導致物種間功能特徵的差異，Chagnon等人認為叢枝菌根菌 (arbuscular mycorrhizal fungi, AMF) 間也有此現象，提出AMF C-S-R framwork，用於預測叢枝菌根菌的生活史策略，但未有田野相關研究。本研究調查阿里山、大雪山、觀霧三個地區三個海拔的紅檜AMF，每個樣區選6棵間隔3公尺以上之紅檜樣木，採取樣木周邊4個方位之紅檜細根與根圈土壤，細根與根圈土壤各24個樣本的DNA分別混合成樣區的代表樣本，進行高通量定序。紅檜根樣本共獲得8,582,411條有效序列，分屬95個VT (virtual taxa)。土壤樣本共獲得10,485,054條有效序列，分屬121個VT。紅檜的叢枝菌根菌有Acaulospora、Ambispora、Archaeospora、Claroideoglomus、Diversispora、Glomus和Scutellospora 7屬，以Glomus和Acaulospora為優勢。部分紅檜的叢枝菌根菌只在特定樣點被調查到，可能有棲地偏好。CLAM分析結果顯示各屬叢枝菌根菌有一至三種生活史策略，但有偏好的生活史策略。Acaulospora、Archaeospora、Diversispora和Scutellospora 4屬大多在土壤中的生物量較高 (競爭型)；Ambispora則對根部有偏好 (雜草型)。Claroideoglomus和Glomus 兩屬大多在根內外有相近的生物量 (耐壓型)。將CLAM分析結果分別連結AMF C-S-R framwork與棲地環境因子資料進行冗餘分析，發現耐壓型AMF在環境壓力較高的地區 (大雪山海拔1,500與2,000公尺樣點) 族群量較多，以Glomus屬為主 (79%)；競爭型AMF在環境壓力較低的地區 (阿里山海拔2,000公尺樣點、觀霧海拔1,500公尺樣點) 族群量較多，以Acaulospora屬為主 (30%)，但皆未達顯著。AMF的功能性狀具系統發育保守性，適合以群落譜系生態學探討其群落構建機制，其群落關乎森林生態系統的生產力、維持生態平衡，了解其群落的構建機制具有生態學意義。本研究發現AMF平均譜系距離與隨機模型沒有顯著差異，群落譜系非聚集也非發散，沒有顯著的環境篩選與競爭作用，但在觀霧的樣點有隨著海拔上升而愈趨聚集，可能有環境篩選現象。ANOSIM分析顯示AMF群落結構顯著受海拔影響；土壤總氮量、總磷量、有機質與pH值，和年均溫、年雨量對其影響均不顯著。
Chagnon et al. suggested that the trade-off in life history characteristics of species causes interspecies difference of functional traits existing among arbuscular mycorrhizal fungi (AMF), and proposed C-S-R framework identifies three life history strategy of AMF. However, there is no field research to verify it. This study investigated AMF diversity of Chamaecyparis formosensis at 1,500 m, 2,000 m and 2,500 m a.s.l. of Alishan, Dasyueshan and Guanwu. For each site, the roots and rhizosphere soil in 4 directions of 6 C. formosensis, at least 3 meters apart, were taken, then the DNA of 24 fine root and 24 rhizosphere soil samples were mixed respectively as the representative sample for each region and processing high-throughput sequencing. A total of 8,582,411 effective reads were obtained from the root samples of C. formosensis belong to 94 VT. In soil sample, there were 10,485,054 effective reads were obtained and belong to 121 VT. Acaulospora, Ambispora, Archaeospora, Claroideoglomus, Diversispora, Glomus and Scutellospora symbiotic with C. formosensis belone to 7 genera, Glomus and Acaulospora were dominant. Some AMF of C. formosensis were investigated at specific site, probably had habitat preference. The results of CLAM analysis showed that there were one to three kinds of life history strategies of AMF, but they had a preferential life history strategy. Most VT in Acaulospora, Archaeospora, Diversispora and Scutellospora had higher biomass in soil (competitor). Ambispora preferred roots (ruderal). Claroideoglomus and Glomus had similar biomass in roots and in soil (stress tolerates). The results of CLAM were associated with AMF C-S-R framework, analyzed with environmental factor by redundancy analysis. The results showed that stress tolerance AMF had higher abundance at higher stress sites (DM, DL), competitors had higher abundance at lower stress sites (AM, JL), and most of them were Glomus (79%) and Acaulospora (30%), respectively, but these data were not significant. The functional traits of AMF are phylogenetically conservative and it is suitable to explore the community assemblage by phylogeny and community ecology. Their community assembly increases the production of forest and balances its ecology. It is important to understand the community assembly mechanism of AMF. In this study, the MPD of AMF community phylogenetics were not significant, which showed that the AMF community assemblage was neither clustering nor overdispersion. But the AMF community phylogenetics were significant clustering in guanwu while altitude increasing, which could be interpreted as environmental filter. ANOSIM test showed that, AMF community was affected by elevation significantly, but the effect of total nitrogen, total phosphate, organic matter, pH value, annual temperature and annual precipitation on the AMF community structure was not significant. |
