• 作者： 江有龍
• 作者服務機構： 國立臺灣大學植物學系
• 中文摘要： 美洲水蕨抱子囊含有孢子的數目，不一定全都會達到32個的滿數，常常會有比這個數目少的
  情形發生。一個孢子囊中含有孢子的大小，有時候很均勻，但有時也會大小不均，一般地說，孢
  子小其發芽率會比較差。利用培養皿做多孢子培養，孢子發芽後會發達成雌、雄體以及雌雄同體
  三種原葉體，但是如果改用培養瓶培養時，因許多孢子都集中在面積狹小的瓶底，故只能得到潛
  在的雌性和雄性的個體，這些個體的生長，遠不如在皿中生長的原葉體。所謂潛在的雌性個體，
  即是具有典型的雌原葉體特有之分生組織，?沒有藏卵器的準雌性原葉體。然而在長期多孢子培
  養瓶內，我們始終無法得到具有藏卵器的個體。用培養皿進行單孢子培養時，我們在5個實驗皿
  中得到一個由小型孢子所長成的雄原葉體，同時亦發現雌的原葉體可由大型及小型的孢子中長成
  ，大概說在單孢子培養中大型孢子發達成的原葉體也會比較大。另一方面用培養瓶做單孢子培養
  ，我們得到的雌原葉體大部分呈現較長而寬闊的帶狀，但總是無法找到雄的個體，所能得到的，
  只是發育較遲而具有褐色細胞塊的小原葉體，此種個體經長期培養後，會進行開放方式的生長，
  最後也會長成雌雄同體的原葉體。在雙孢子培養中，我們看到2個孢子都發芽時，其中一個會
  長成雌的或類雌的原葉體（無性的原葉體），另一個總是長成雄的，如果2個子孢子中只有一個
  發芽時，那麼它也總是長成雌的或類雌的，類雌的個體是在長藏卵器的地方不長藏卵器，而長出
  無性芽的一種原葉體。在多孢子培養皿中得到的雌、雄體以及雌雄同體的個體，如果將之移植隔
  離培養，那麼單性的原葉體會發達成為兩性後自家受精而形成幼孢子體，本來就是兩性的原葉體
  於移植後也同樣的會形成孢子體（同株性的intragametophytic)，然而孢子體也可以是異株性的
  intergametophytic。幼孢子體的葉間期約為7天。在實驗中，我們看到一個單株原葉體在孢子體
  形成後生長便逐漸的受到抑制，而隨著孢子體的成長，原葉體的存在愈來愈不明顯，很顯然的孢
  子體對原葉體有某種的生長優勢現象。總括本次對孢子及原葉體性呈現的研究，我們所得到的結
  論是：孢子的大小和性別是孢子在孢子體上形成時便已被決定的，但是在以後孢子的發達過程中
  ，孢子外因素也會很顯著的影響到原葉體的性別。
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• 英文摘要： The sporangium of Ceratopteris pteridoides(Hook.) Hieron. contains 32 or less spores ofequal or unequal size. The smaller spores areless germinable than the larger ones. In multi-spore dish cultures, spores give rise to female,male and hermaphroditic prothallia. In the vial,however, they develope only to be male and "po-tential" female prothallia. A potential femaleprothallium is the immature meristic prothal-lium which has a potential to form archego-nium. Yet, none of the male or potential fe-male prothallia crowded on the bottom of thevial formed female sex organ when the cultureperiod was extended. In the monospore dishculture, the small spore gave rise to eithermale or female prothallium, whereas the largerspore usually formed a larger or female pro-thallia. In the vial, on the other hand, theisolated spore gave rise to a female prothalliumof a more or less elongated type. Male pro-thallia were not found in any of the monosporeculture vials. Instead, a small "male-like" pro-thallium with a brownish mass of cells, or a bud(or a mass of "antheridioids"？). was constantlyfound. In a prolonged cultivation period up toabout 100 days, this type of small prothalliumgrew by expanding or budding to become a her-maphrodite. In dual-spore cultures, if bothspores germinated, one was always female or afemale-like prothallium whereas the other was amale. A female-like prothallium is an asexual (orneutral) prothallium which produces vegetativebud(s) instead of archegonia. It was found thatthese adventitious structures were the undevel-oped archegonia or "archegonioids". If onlyone spore germinated, it grew to be a femaleor an asexual prothallium. In transplantingexperiments, the monoecious prothallium pro-duced an embryo by selfing or intragame-tophytic mating in the isolate culture. Thedioecious prothallium on the other hand formedthe organ of the opposite sex during isolateculture for intragametophytic fertilization.Fertilization, however, also occurred intergame-tophytically. The plastochron of the sporelingtook about 7 days under normal experimentalcondition. The growing sporophyte was foundto exhibit a certain dominance on the prothal-lium. The data presented in this paper showsthat although the sex of the spores of Cerato-pteris pteridoides are determined when the sporeis formed on the sporophyte, the sex of theprothallium is greatly affected by various exo-sporic factors.
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