阔叶鳞盖蕨和粗毛鳞盖蕨(碗蕨科)配子体发育的研究

以腐殖土为基质,对阔叶鳞盖蕨Microlepia patyphylla（D．Don）J．Sm．和粗毛鳞盖蕨M.strigosa（Thunb．）Presl进行了孢子繁殖;利用光学显微镜观察和记录了它们的孢子萌发和配子体发育过程。结果表明,两者的孢子及配子体性状极为相似：孢子同型,三裂缝,萌发慢;孢子萌发需要光,萌发方式为书带蕨型Vittaria-type;配子体生长慢,发育类型为铁线蕨型Adiantum—type;原叶体心形或其他形状,无毛状体,多数为雌雄异株。性器类型为薄囊蕨型Leptosporangiate-type。它们既具有大量的原始性状,也具有少数进化性状。与阔叶鳞盖蕨相比,粗毛鳞盖蕨的配子体发育特征更为原始。说明粗己鳞盖蕨的系统位置更加低下。首次观察到阔叶鳞盖蕨中细胞自然死亡时的叶绿体聚集现象。粗毛鳞盖蕨原叶体老化时叶绿体呈现规则的、相互镶嵌的多边形的形状以及在正常光照下粗毛鳞盖蕨某些细胞中的部分叶绿体成链珠状排列等现象。     

Relations between submarginal and marginal sori in ferns

In contrast to the generally favoured hypothesis that the marginal position of sporangia and sori is the primitive condition, Hagemann (e.g. 1984a) holds the view that the superficial position of reproductive organs is primitive. Marginal reproductive organs correlate with a distinct succession of a vegetative and a reproductive developmental phase in the sporophyll (phase differentiation in leaf development). Since phase differentiation means an increase in complexity, marginal reproductive organs are considered advanced. In order to examine the relations between submarginal and marginal sori in the light of Hagemann's hypothesis, various soral forms of ferns were analysed using the methodological framework of construction morphology sensu Weber (1958). The sorus is regarded as a reproductive region of the leaf surface that comprises not only the sporangia but also the receptacle as an essential component. The growth pattern of the receptacle, the developmental succession of the sporangia, and the formation of the indusia lead to the recognition of several sorus types.In the present paper the basipetal marginal sorus is presented and defined as the combination of (a) a ridge-, cushion-, or rod-shaped receptacle, (b) a basipetal sequence of sporangia initiation, and (c) the presence of a lower and an upper indusium or of a cup-shaped indusium. As the first examples of this type, the sori of selected Hypolepidaceae and Dennstaedtiaceae are treated in detail. Regarding the phylogenetic relationships of the present families, the following conclusions can be drawn: (1) Owing to the meristem fusion of the indusia the sorus ofDennstaedtia possesses a new quality as compared to that of the Hypolepidaceae. Therefore, the Hypolepidaceae and the Dennstaedtiaceae should not be combined in a single family, as suggested by some authors. (2) The marginal position of the sori, and, in addition, the highly complex soral construction of the Dennstaedtiaceae, are not in support of the primitiveness of the two families, as sometimes assumed. (3) A sorus construction as found inDennstaedtia glauca can be gradually derived from a less elaborate one, such as that found, e.g., inPteridium. The continuous increase in the perfection of the soral construction (Pteridium Dennstaedtia) suggests a placement of the Dennstaedtiaceae after the Hypolepidaceae.     

Biosynthesis of pteroside B in Pteridium aquilinum var. Latiusculum,proof of the sesquiterpenoid origin of the pterosides

Pteroside B was isolated in radioactive form after administration of [2-¹⁴C]mevalonate to Pteridium aquilinum var. latiusculum, demonstrating that the biosynthesis of the aglycone proceeds through the ordinary pathway to sesquiterpenoids. Kuhn-Roth oxidation of the radioactive aglycone was carried out to examine the distribution of the radioactivity among the 3 methyls of the aglycone. The biosynthetic implications of these results are discussed.