国产对囊蕨亚科(蹄盖蕨科)植物的管状分子

利用扫描电镜观察了国产蹄盖蕨科(Athyriaceae)对囊蕨亚科(Deparioideae)10种植物及双盖蕨属(Diplazium Sw.)3种植物根状茎的管状分子。结果显示, 这些管状分子端壁和侧壁的形态及结构分别相同且侧壁具有穿孔板(多穿孔板)。根据穿孔板的形态特征, 将该亚科的管状分子分为5种类型: (1)梯状穿孔板, 无穿孔的二型性现象; (2)梯状穿孔板, 有穿孔的二型性现象; (3)网状穿孔板; (4)梯状-网状混合的穿孔板; (5)大孔状穿孔板。按照纹孔膜残留的程度又可分为3种: 部分区域有完整的纹孔膜、残留呈网状或线状以及很少或无纹孔膜残留。结合前人的研究资料, 发现蕨类植物的管状分子与被子植物的导管分子在形态和输导机理上存在明显差异, 管胞和导管分子不能仅仅根据纹孔膜的存在与否来确定, 而应根据穿孔板存在于端壁还是侧壁进行判断, 即穿孔板仅存在于端壁的管状分子为导管分子; 端壁和侧壁形态及结构分别相同, 有或无穿孔板的管状分子为管胞。由此可以推测蕨类植物和裸子植物中输导水分和矿物质的管状分子主要为管胞。单叶双盖蕨属(Triblemma(J. Sm.) Ching)与双盖蕨属管状分子的特征并不相似, 显示了将单叶双盖蕨属从双盖蕨属独立出来归入对囊蕨亚科的合理性。根据管状分子的特征, 推测假蹄盖蕨属(Athyriopsis Ching)和蛾眉蕨属(Lunathyrium Koidz.)可能是比较进化的属, 而介蕨属 (Dryoathyrium Ching)相对比较原始, 单叶双盖蕨属的系统位置应介于假蹄盖蕨属与介蕨属之间。

Study of Tracheary Elements in Deparioideae(Athyriaceae)from China

Tracheary elements of rhizomes of 10 species of Deparioideae (Athyr iaceae) and three species of Diplazium Sw. from China were examined by scanning electron microscopy. The end walls of cells have the same morphological characteristics and structure as the lateral walls. The lateral walls contain perforation plates (multi-perforation plates ). According to the characteristics of perforation plates, tracheary elements of Deparioideae could be divided into five types: scalariform without dimorphic width perforation; scalariform with perforation pit dimorphism; reticulate plates; reticulate-scalariform plates; and coarse-pored perforation plates. According to the degree of pit membrane remnants, tracheary elements could also be divided into the following three types: intact pit membrane on part region; thread-like or web-like structure; and little or no pit membrane remnants. Tracheary elements in ferns and vessel elements in angiosperms have different morphology and transfer mechanisms. The identification of vessle elements and tracheids should depend on the fact that per foration plates exist on the end walls or lateral walls, rather than the presence of a pit membrane. So tracheary elements with perforation plates only on the end walls are vessel elements. Tracheids have end walls and lateral walls with the same morphological characteristics or structure, with perforation plates or not.From the present results, we considered that tracheary elements that conduct water and mineral in ferns and gymnosperm are tracheids. Tracheary elements of Triblemma (J. Sm.) Ching and Diplazium differ, so Triblemma can reasonably be transferred from Diplazium to Deparioideae. Athyriopsis Ching and Lunathyrium Koidz. might be more advanced, Dryoathyrium Ching might be relatively primitive in Deparioideae, and the systematic position of Triblemma should be between Athyriops is and Dryoathyrium Ching.