Sheffield E, Laird S, Bell P R
J Cell Sci. 1983 Sep;63:125-34. doi: 10.1242/jcs.63.1.125.
The events that accompany sporogenesis in the apogamous fern Dryopteris borreri parallel those seen in sexually reproducing ferns. Organelles dedifferentiate and redifferentiate, and form a discrete band across the equator of dyads; nuclear vacuoles and lipid spherosomes appear during prophase, and the major part of the ribosome population is removed and subsequently replaced during meiosis. Similar events have been found to occur during sporogenesis in mosses, gymnosperms and angiosperms, and therefore characteristic of the meiotic transition from sporophyte to gametophyte, even in the absence of a transition from diplophase to haplophase. The novel aspects of meiosis in D. borreri are largely those connected with the restitution event that precedes meiosis I and serves to maintain the sporophytic chromosome number throughout the life cycle of this fern. Pre-meiotic cells are regularly found to be cleaved by annular wall ingrowths, which traverse the cytoplasm but not the nuclei. The significance of these ingrowths in relation to theories concerning apogamy and plant cell division are discussed.
无融合生殖的蕨类植物博勒鳞毛蕨中伴随孢子发生的事件与有性生殖的蕨类植物中所见的事件相似。细胞器去分化并重新分化，在二分体的赤道面上形成一条离散的带；核液泡和脂质球在前期出现，核糖体群体的主要部分在减数分裂期间被去除并随后被替换。已发现类似事件在苔藓植物、裸子植物和被子植物的孢子发生过程中也会发生，因此即使在没有从二倍体阶段到单倍体阶段转变的情况下，这些也是从孢子体到配子体减数分裂转变的特征。博勒鳞毛蕨减数分裂的新特点主要与减数分裂I之前的恢复事件有关，该事件有助于在这种蕨类植物的整个生命周期中维持孢子体的染色体数目。经常发现减数分裂前的细胞会被环状壁内突切割，这些内突穿过细胞质但不穿过细胞核。讨论了这些内突与关于无融合生殖和植物细胞分裂的理论的关系。
