| 摘要: | 沙岸植物是一種生存在沙灘這類特殊棲息地，能忍受缺乏營養、高鹽分、強風吹襲和太陽輻射強
的逆境。許多只生長在沙岸的草本植物構成了這一種特殊的植被。這些沙岸植物具有防風、定沙，
保護海岸的功能同時也是扮演沙濱生態系的重要角色。可是這種植被目前卻面臨被破壞的危險。
因為海平面的不斷的上升，加上人為的破壞，可能會使得許多適應這類環境的生物消失。目前已
知內生真菌對於生存在逆境環境的植物有很重要的影響，可是我們對於熱帶/亞熱帶沿海草本植
物的內生菌卻所知甚少。我們的研究目的是檢測和鑑定蔓荊和馬鞍藤這兩種台灣主要海岸植物的
內生真菌並分析真菌是否特異存在於植物物種或是器官和組織。研究兩種植物真菌的組成和多樣
性，預計能提供有關真菌的地理和宿主分佈的新數據，而新發現的菌株和其DNA 數據將被保存
以供未來的研究應用。我們從1782 個蔓荊植物片段中分離了1072 個真菌菌株在這其中有76 個
種類。我們也在2304 個馬鞍藤植物片段中分離了885 個真菌菌株在這其中有140 個種類。這些
種類大多都是其宿主的新的紀錄，在這其中我們也發現一個新物種Alpestrisphaeria sp. nov.，此
物種僅在蔓荊的根和莖中發現。在優勢種中只有Aspergillus terreus 是同時存在於兩種植物體內。
在真菌群落方面，馬鞍藤在自然沿海棲息地和人工植物園之間存在顯著差異。在沿海棲息地，潛
在的致病真菌比腐生真菌更為罕見，這可能表明腐生內生菌在養分循環中的重要性，特別是在植
物被沙子掩埋後腐爛葉片。數據表明內生真菌的種類受到其棲息地、植物物種以及植物器官所影
響。除了內生真菌的研究之外，我們還研究了植物的外生真菌，以解決內生真菌、寄生真菌和腐
生真菌之間是否存在明確分界的問題。在植物園種植的蔓荊中我們發現了Corynespora cassiicola
這株葉片病原體，但在野生外的蔓荊中沒有發現其內生菌紀錄。Dinemasporium spinificis 是台灣
的第一個記錄，為濱刺草上的外生腐生菌，但在先前的濱刺草內生菌研究中沒有其內生真菌的紀
錄。;Herbaceous vegetation at sand coasts consists of specific plants which can tolerate high salinity,
wind and sand movements, and lack of nutrients, and are, therefore, important for coast protection and
preventing erosion, but are outcompeted in inland habitats. Although this vegetation in Taiwan on the
one hand is endangered by construction, tourism and other human activities, as well as rising sea level,
and on the other hand fungal endophytes are known to have a strong influence on the survival of plants
under such stress factors, few is known about the endophytes of tropical/subtropical coastal herbaceous
plants. The aim of the study was to detect and identify endophytic fungi of Vitex rotundifolia and
Ipomoea pes-caprae, two of the most common plants along the shore of Taiwan, and to analyze
whether fungi were specific to plant species, certain organ or tissues. The study on composition and
diversity of fungi from both plants provided new data about the geographical and host distribution of
fungi, led to the discovery of new species and new fungal records. New isolates and DNA data were
deposited for future systematic and biotechnological studies and applications. We isolated 1072 strains
comprising 76 species from 1782 plant fragments of Vitex rotundifolia and 885 strains comprising 140
species from 2304 fragments of Ipomoea pes-caprae, which were identified with genetic markers as
well as with morphology. These species most are new records for their hosts. Among these species,
Alpestrisphaeria sp. nov. was considered as new and was found only in roots and stems of V.
rotundifolia. Only Aspergillus terreus was a common species in the top three dominant species from
both plants. Fungal communities in I. pes-caprae differed significantly between natural coastal habitats
and artificial plantations in botanical gardens. In coastal habitats, potentially pathogenic fungi were
rarer than saprobic species, which might indicate the importance of saprobic endophytes in nutrient
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cycling particularly of decomposing leaves after sand burial. The data indicate that occurrence of
endophytic fungal species is driven by the habitat, plant species, and plant organ. Except for the study
of endophytic fungi, examples of ectophytic fungi were studied for addressing the question whether
there is a clear-cut demarcation between endophytic, parasitic and saprobic fungi. Corynespora
cassiicola was found as leaf pathogen on artificially planted V. rotundifolia, but not as endophyte in
wild populations. Dinemasporium spinificis, a first record from Taiwan, was found only as ectophytic
saprobe on Spinifix littoreus, but was not recorded as endophyte from this plant in previous studies. |
