【作者】 徐皓；

【导师】 王玛丽；

【作者基本信息】 西北大学 ， 植物学， 2006， 硕士

【摘要】 假冷蕨属(Pseudocystopteris)是秦仁昌(1964)根据原产我国东北的假冷蕨Cystopteris spinulosa Maxim。建立的一个新属,因其根状茎细长横走几无鳞片,叶柄基部不为膨大的纺锤形,向下不变尖削,孢子囊群圆形,生于小脉背上,囊群盖为肾圆形或肾形,基部羽片从不缩短,而且往往最长,将假冷蕨属从蹄盖蕨属(Athyrium)中分出来独立,分类位置介于冷蕨属(Cystopteris)和蹄盖蕨属之间。但Kato(1977)及Tron和Tron(1982)并不支持秦仁昌的观点,主张把假冷蕨属归并到蹄盖蕨属中。Sano等(2000)、王玛丽等(2003)根据分子系统树分析发现假冷蕨属与蹄盖蕨属成员组成一支,支持后者的观点。本文对假冷蕨属、冷蕨属、蹄盖蕨属的孢子形态、叶表皮、管状分子、鳞片和叶柄的解剖特征等方面进行了系统研究,以确定假冷蕨属合理的系统位置。 1 孢子形态研究 假冷蕨属、蹄盖蕨属、冷蕨属植物的孢子外部形态相同,孢子极面观为椭圆形,赤道面观为豆形。假冷蕨属的孢子周壁纹饰为不规则脊状褶皱,有的连接成网状。蹄盖蕨属的孢子周壁纹饰两种类型,一种为拟网状;一种与假冷蕨属相似,为不规则脊状褶皱。冷蕨属与前两属差异较大,主要为刺状突起。假冷蕨属和蹄盖蕨属孢子的环带数目在13～14个之间,而冷蕨属孢子都在15个以上。 2 叶表皮特征研究 假冷蕨属和蹄盖蕨属植物上表皮细胞多为波状,冷蕨属植物的上表皮细胞多为不规则凹凸状。从气孔器的类型来看,三属植物共有腋下细胞型、极细胞型、不规则四细胞型、不规则型、共环极细胞型五种类型。假冷蕨属和蹄盖蕨属主要以腋下细胞型为主,且都存在极细胞型和共环极细胞型气孔器,而冷蕨属主要以不规则四细胞型为主,无极细胞型和共环极细胞型气孔器。假冷蕨属和蹄盖蕨属的气孔密度都在20个/mm~2以上,而冷蕨属的都小于20个/mm~2,介于15～20个更多还原

【Abstract】 Pseudocystopteris was suggested as a new genus by Ching Ren-Chang in 1964 in light of Cystopteris spinulosa Maxim, which grows in northeast of China. Because the rhizoma late repente has few scales, the basal of petiole is not inflated spindle and does not become tapemess downward, the soris is round growing in later anteriore venularum, indusium is circle reniform or reniform, the basal pinnae never shorten and is often the longest. Consequently, Pseudocystopteris was separated from Athyrium and the systematical position is between Cystopteris and Athyrium. But Kato (1977) and Iron &Tron (1982) did not support his viewpoint and they claimed that Pseudocystopteris should be classified in Athyrium. Sano (2000) and Wang Ma-li (2003) found that Pseudocystopteris and the member of Athyrium belong to the same branch based on the molecule evolutionary-tree, and agreed with the latter. Many features of Pseudocystopteris, Cystopteris, and Athyrium were investigated systematically in this paper, including morphology of spore, leaf epidermis, tracheary elements, the anatomy character of scale and petiole, so that the systematical position of Pseudocystopteris can be determined.1 Morphological research of sporeThis three genuses share the same exterior morphology of spore, the spore is ellipse from polar sight and bean shape from equator sight. The surface ornamentation of perine of Pseudocystopteris has irregular lophate folds, with some joined into reticulate. The surface ornamentation of perine of Athyrium is divided into two types: one is ornate, the other is similar to Pseudocystopteris, and also has irregular lophatefolds. The surface ornamentation of perine of Cystopteris obviously different from those of the two former genuses is echinate. The number of clitellum in Pseudocystopteris and Athyrium is between 13 and 14, while that is above 15 in Cystopteris.2 Research of leaf epidermis characterIn Pseudocystopteris and Athyrium, the shape of up epidermis are sinuate, the shape of up epidermis of Cystopteris is irregular concaveconvex. As for the stomatal style, there are five types, such as axillocytic type, polocytic type, anomotetracytic type, anomocytic and copolocytic type. The axillocytic type is the main pattern in Pseudocystopteris and Athyrium, which both have polocytic type and copolocytic type. But, anomotetracytic type is the main pattern in Cystopteris, which have not polocytic type and copolocytic type. In Pseudocystopteris and Athyrium, the stomatal density is usually above 20 pieces /mm2, but in Cystopteris that is less than 20 pieces /mm2, ranging from 15 to 20.3 Research of tracheary elementsTracheary elements of rhizomes in Pseudocystopteris, Athyrium and Cystopteris were examined by scanning electron microscopy (SEM). The results indicated that the end walls and lateral walls both have perforation plates, whose pit membrane is left more or less. The perforation plates of the three genus could be divided into four types: 1) scalariform perforation plates, without dimorphic width perforation;2) scalarifonn perforation plates with dimorphic width perforation;3) reticulate perforation plates;4) scalariform-reticulate perforation plates. The remnants degree of pit membrane could also be divided into the following three types: 1) partly intact pit membrane on part region;2) threadlike or weblike in structure;3) few or without pit membrane remnants.Judging from the evolution of the perforation plates types, scalariform perforation plates is original, reticulate perforation plates is evolutional, and scalariform-reticulate perforation plates is a intermediate type. Pseudocystopteris has scalariform perforation plates and scalariform-reticulate perforation plates;Athyriumhas scalariform perforation plates and reticulate perforation plates;Cystopteris only has scalariform perforation plates. It shows that Pseudocystopteris and Athyrium have close relationship and the systematic position is relatively higher, and Cystopteris occupies a lower position.At the same time, the observation results show that compared with tracheary elements of angiosperm, the three genuses have unobvious end walls and there are perforation plates or multi-perforation plates on lateral walls. So, we think that the identification of vessle elements and tracheids should depend on the fact that perforation plates exist on the end walls or lateral walls, rather than presence of pit membrane. So tracheary elements which have perforation plates only on the end walls are vessel elements, tracheary elements that have perforation plates or not and whose end walls unobvious are tracheids. Based on the present results, we consider that tracheary elements which conduct water and mineral in ferns and gymnospenn are largely tracheids.4 Morphology and anatomy researchBy comparison with rhizoma, insertion manners of lamina, ornamentation of perispore, indusium and other aspects, we found that Pseudocystopteris is similar to Athyrium on some morphological characters , and basic number of chromosome are both 40 which show that they have close relationship. And that , the similarity of Cystopteris and Athyrium is much less than the former, and basic number of chromosome in Cystopteris is 42.According to inspection on scale of rhizoma, the three genuses have similarity on the shape of scale and lumina, all are lanceolate and long shuttled, but the margin of scales of Cystopteris has hair and glandular hair, while Pseudocystopteris and Athyrium not have this character.Crosscuting the basal of petiole, it was observed that the cross section of three genuses all have meristele, which are amphicribral vascular bundle. The cross section of Pseudocystopteris and Athyrium is oblateness, and the two meristele are sliver shape, distributing in the shape of "A", the xylem in the two meristele are typicalhippocampus type. The two meristeles of Cystopteris on the cross section are nearly round in which the xylem is not typical hippocampus type.Based on the above-mentioned and combined with molecular, cytological and auxanological characters, we conclude that Pseudocystopteris has close relationship to Athyrium, it should be moved to Athyrium. The correct names of seven genus in Pseudocystopteris should be:Athyrium atkinsonii Bedd.Athyrium spinulosum Milde.Athyrium subtriangulare Hook.Athyrium schizochlamys (Ching) M L Wang et H Xu. comb. nov.Athyrium atuntzeensum (Ching) M L Wang et H Xu. comb. nov.Athyrium davidii Christ.Athyrium repens (Ching) M L Wang et H Xu. comb. nov.更多还原