The gametophyte and embryo of Polyphlebium venosum (R. Br.) Copeland (Hymenophyllaceae)
The gametophyte and embryo of Polyphlebium venosum (R. Br.) Copeland (Hymenophyllaceae)
复制标题
DOI：
10.1071/bt9580183
复制
发表时间：
1958
影响因子：
1.1
通讯作者：
I. Stone
中科院分区：
文献类型：
--
作者：
I. Stone
本文叙述了多脉菌的孢子及其萌发、纤细的丝状原叶体、生殖器官、胚胎和幼孢子体。特征萌发，这是四细胞或毛滴虫类型的修改，在各种条件下保持不变。首先出现假根，几周后出现丝状细胞。没有达到对称的四细胞阶段，但3个月后，另一个假根或花丝细胞往往从初生细胞上切下。雌雄同株的配子体是一个分枝单列的丝状体，有许多小的有柄的精子器，每个精子器都有一个简单的壁，和一个升起或脱落的盖，以允许精子逃逸。颈卵器，直颈，颈细胞层为4 ~ 6个，生于特殊结构的颈卵器托上。原叶体通过再生和芽的方式进行无性繁殖，芽在萌发时产生假根、花丝和精子器或更多的芽。胚胎是毛脉类的第一个描述，研究表明它是不寻常的。没有初生根，一个颈卵器柄可能带有一个以上的胚胎，并且胚胎的轴相对于颈卵器颈部的位置不同，可能是因为颈卵器在颈卵器柄上的不同位置。这表明胚胎的发育方式使足与食物供应源有尽可能大的接触。配子体和胚显示出一些原始的特征，但最显著的特征是为适应潮湿和荫凉的环境而以退化形式特化。附录了维多利亚时代的膜蕨科检索表。
An account is given of the spore, its germination, the delicate filamentous prothallus, the reproductive organs, the embryo, and the young sporophyte of Polyphlebium verzosum. The characteristic germination, which is a modification of the four-celled or Trichomanes type, remains unchanged under various conditions. A rhizoid appears first, followed after several weeks by a filament cell. The symmetrical four-celled stage is not attained, but after 3 months another rhizoid or filament cell is often cut off from the primary cell. The monoecious gametophyte is a branching uniseriate filament and bears numerous, small, stalked antheridia, each with a simple wall, and an operculum which is raised or shed to allow the spermatozoids to escape. The archegonia, with straight necks, and tiers of four to six neck cells, are borne on special structures, the archegoniophores. The prothallus reproduces itself vegetatively by regeneration, and by gemmae which on germination produce rhizoids, filaments, and antheridia or more gemmae. The embryo is the first described for the Trichomanes group, and the investigation showed it to be unusual. There is no primary root, a single archegoniophore may bear more than one embryo, and the axis of the embryo varies in its position relative to the neck of the archegonium, possibly because the archegonia are borne in various positions on the archegoniophore. The suggestion is made that the embryo develops in a manner which gives the foot as large a contact as possible with the source of food supply. The gametophyte and embryo show some primitive characters, but the most conspicuous feature is specialization in the form of reduction as an adaptation to a moist and shady environment. A key to the Victorian Hymenophyllaceae is appended.