Isoetes taiwanensis is a species of plant in the family Isoetaceae. It is endemic to Taiwan, and the only species of quillwort there. As other quillworts, it is relatively small, with erect leaves 7–24 cm (2.8–9.4 in) long. It grows submersed in shallow ponds for most of the year.[2] IUCN considers it critically endangered because of habitat loss.[1]
The first quillwort genome sequence was of I. taiwanensis.[3] This showed that there were differences in its biochemistry from terrestrial plants that had adopted the same strategy for CO2 fixation, namely Crassulacean acid metabolism (CAM). This involves the enzyme phosphoenolpyruvate carboxylase (PEPC) and plants have two forms of the enzyme. One is normally involved in CO2 fixation during photosynthesis and the other in central metabolism. From the genome sequence, it appears that in I. taiwanensis both forms are involved in photosynthesis. In addition, the time of day of the peak abundance of some of the components of CAM was different from terrestrial plants. These fundamental differences in biochemistry suggests that CAM in I. taiwanensis, and likely all quillworts, is another example of convergent evolution of CAM.[3]
Isoetes taiwanensis is a species of plant in the family Isoetaceae. It is endemic to Taiwan, and the only species of quillwort there. As other quillworts, it is relatively small, with erect leaves 7–24 cm (2.8–9.4 in) long. It grows submersed in shallow ponds for most of the year. IUCN considers it critically endangered because of habitat loss.
The first quillwort genome sequence was of I. taiwanensis. This showed that there were differences in its biochemistry from terrestrial plants that had adopted the same strategy for CO2 fixation, namely Crassulacean acid metabolism (CAM). This involves the enzyme phosphoenolpyruvate carboxylase (PEPC) and plants have two forms of the enzyme. One is normally involved in CO2 fixation during photosynthesis and the other in central metabolism. From the genome sequence, it appears that in I. taiwanensis both forms are involved in photosynthesis. In addition, the time of day of the peak abundance of some of the components of CAM was different from terrestrial plants. These fundamental differences in biochemistry suggests that CAM in I. taiwanensis, and likely all quillworts, is another example of convergent evolution of CAM.
Isoetes taiwanensis là một loài dương xỉ trong họ Isoetaceae. Loài này được De Vol mô tả khoa học đầu tiên năm 1972.[2]
Isoetes taiwanensis là một loài dương xỉ trong họ Isoetaceae. Loài này được De Vol mô tả khoa học đầu tiên năm 1972.
台灣水韭（學名：Isoetes taiwanensis），屬於水韭科（Isoetaceae），葉長7至24公分[2]。
台灣水韭是在1971年由徐國士及張惠珠首次發現。台灣只有此種水韭，分佈於陽明山的夢幻湖，這是全球六十多種的水韭科植物之中，生長倒數第二接近赤道的植物，（最接近赤道的水韭位於金門）[3]。最早起源於距今約2.5億年前的三疊紀早期，同時也是一種活化石植物，其相近親緣植物均盛產於恐龍稱霸的白堊紀時代，距今約6550萬年至1億4550萬年前，如Isoetites、Nathorstiana 和Stylits現均已滅絕，獨留低矮草狀的水韭至今，故在稙物分類學及演化學的研究上具有相當重要之地位。是臺灣特有種的稀有植物，大約於5000年前就出現在夢幻湖之中，是一種非常稀有的水生蕨類植物 ( 石松類植物 ) 。為多年沉水或挺水之水生草本植物。
台灣水韭、台灣水韮、臺灣水韮、Taiwan Quillwort
高約 5~15 公分，球莖短，且具三至四個突起。
生長在水底泥地。
葉子小且細長，大約長5~25公分，只具有單脈。因生長在泥地，通氣組織發達。常常叢生在一起，約為15~90片，沉水浮水皆有。葉片上面部分扁平，下面部分呈現圓形。葉尖有散生氣孔，葉舌呈長三角形，而基部的外緣則有薄膜。葉膜退化或僅覆蓋孢子囊頂部。
孢子囊生於葉子基部的內側，有大小之分。大的呈現卵囊形，潮濕時呈現灰白色，但乾燥時呈現白色；小的則是灰色，橢圓形。
水生綠化植物
隨著科學家們發現最近夢幻湖有逐漸『陸化』的情況出現，不少陸生植物已經開始入侵夢幻湖之中。而這些入侵之陸生植物除了彼此抑制對方的生長之外，當然也抑制了屬於水生植物的台灣水韭之生長。再者，透過實驗科學家也發現，夢幻湖之優勢陸生植物體的萃取液在原液時，本來就具有抑制台灣水韭的孢子萌芽之現象存在。
透過人工來移除入侵之陸生植被的方式，已經明顯有不少台灣水韭於原棲地都恢復了部分的生長量。而不只台灣水韭，其他的水生族群如：七星山的榖精草、小杏菜等等，也都有恢復族群數量的情形出現，由此可見不過當之棲地管理對於整個溼地之中物種的保育是有一定的幫助的。
|access-date=中的日期值 (帮助) 台灣水韭（學名：Isoetes taiwanensis），屬於水韭科（Isoetaceae），葉長7至24公分。
台灣水韭是在1971年由徐國士及張惠珠首次發現。台灣只有此種水韭，分佈於陽明山的夢幻湖，這是全球六十多種的水韭科植物之中，生長倒數第二接近赤道的植物，（最接近赤道的水韭位於金門）。最早起源於距今約2.5億年前的三疊紀早期，同時也是一種活化石植物，其相近親緣植物均盛產於恐龍稱霸的白堊紀時代，距今約6550萬年至1億4550萬年前，如Isoetites、Nathorstiana 和Stylits現均已滅絕，獨留低矮草狀的水韭至今，故在稙物分類學及演化學的研究上具有相當重要之地位。是臺灣特有種的稀有植物，大約於5000年前就出現在夢幻湖之中，是一種非常稀有的水生蕨類植物 ( 石松類植物 ) 。為多年沉水或挺水之水生草本植物。
