The Occurrence of Crassulacean Acid Metabolism in Epiphytic Ferns, With and Emphasis on the Vittariaceae

This is the publisher's official version. It is also available electronically from: http://www.jstor.org/stable/10.1086/430334.The potential for nighttime CO2 uptake and/or increases in tissue acidity characteristic of crassulacean acid metabolism (CAM) was investigated, to varying degrees, in 12 species of Vittariaceae as well as in seven species in four other families of tropical epiphytic ferns. Evidence of CAM (actually CAM cycling, i.e., diei changes in tissue acidity without nighttime atmospheric C 0 2 uptake), though highly variable, was found in two species of Vittariaceae. The ecophysiological significance of this finding is puzzling, because the occurrence of these plants in deeply shaded, extremely moist habitats is rare, if not unique, among plants expressing any degree of CAM. The results of this study confirm that CAM among the ferns is not limited to the Polypodiaceae, and they emphasize the polyphyletic nature of the evolution of CAM among higher plants

Ecophysiology and plant size in a tropical epiphytic fern, Asplenium nidus, in Taiwan

Recent studies indicate that, especially in epiphytes, plant size has a strong influence on the ecophysiology of individual leaves of a plant. Extensive data sets that address this phenomenon, however, are limited to a few taxa of flowering plants. It was the purpose of this study to examine numerous physiological parameters in individuals of varying sizes of Asplenium nidus, a widespread epiphytic tropical fern, in a rain forest in northeastern Taiwan. Although stomatal dimensions and frond thickness did not vary with plant size, frond stomatal densities were higher in larger plants. Frond elemental concentration did not vary with plant size for nitrogen, magnesium, phosphorus, and sodium, while the concentrations of carbon, calcium, and potassium changed with plant size, though in different ways. The osmotic concentration of liquid expressed from the fronds did not change with plant size, nor did chlorophyll concentrations and chlorophyll a/b ratio. Fronds excised from smaller plants contained more water yet lost water at lower rates in laboratory drying experiments. Although rates of net CO2 exchange of the fronds measured in situ in the field appeared to increase with plant size, this increase and other size-related differences in gas exchange parameters were not significant. Although some aspects of the ecophysiology of this epiphytic fern varied with changes in plant size, most physiological parameters did not. Thus, the results of this study lend only little support to past findings that plant size is an important consideration in ecophysiological studies of plants

結合GBIF與MaxEnt預測臺灣赤楊之適宜生育地

選擇合宜的植物種類是植生復育的關鍵第一步，利用新興的物種分布模擬 (SDM) 將有助於正確選擇樹種及確定適宜生育地以提供科學決策。本文以臺灣赤楊為例，使用免費易得的全球生物多樣性資訊機構(GBIF) 物種資料庫、最大熵 (MaxEnt) 物種分布軟體進行其生育地適宜度分析，結果顯示預測模型之準確度評估屬於良好等級 (AUC = 0.842)，所得之預測出現機率可加以繪製臺灣赤楊之生育地適宜度 (HSI) 分布圖，經9 處崩塌地鄰近區域植群調查資料驗證十分吻合，同時本文對未來物種分布模擬尚待解決之相關議題加以討論，期使本地原生植物在水土保持植生復育中更具科學基礎與發揮其應用潛力。Selecting appropriate species is the first key step for vegetation rehabilitation. Novel species distribution modeling (SDM) can assist in making scientific decisions to support species selection and predict suitable habitat. In this paper, we combine the open-access Global Biodiversity Information Facility (GBIF) database and MaxEnt modeling software to predict Alnus formorsana distribution. The results reveal that the accuracy assessment of our model is good within an area of 0.842 according to the receiver operating characteristic curve. We transform the predicted occurrence probability, through ArcGIS, to map the habitat suitability index (HSI) of Alnus formorsana that approximately corresponds with the observed vegetation in 9 nearby landslide areas. Based on our findings, we discuss the future challenges related to SDM. The proposed approach can be used in the future to facilitate proper application of native plants in soil and water conservation