Differentiation of Intracapsular Cells in the Sporophyte of Sphaerocarpos donnellii

Evolution of apolar sporocytes in marchantialean liverworts: implications from molecular phylogeny

“…In Sphaerocarpales, nutritive cells, which lack spiral thickenings, differentiate from archesporial cells and are randomly intermingled in the capsule. Nutritive cells undergo one or two mitotic division after the differentiation of sporocytes (Kelley and Doyle 1975). In Ricciales, even the differentiation of seta and foot is suppressed (Pagan 1932).…”

“…Alternatively, nutritive cells randomly intermingled in the capsule. Sphaerocarpos-type is known in Sphaerocarpos and Riella (Kelley and Doyle 1975;Neidhart 1978;Brown et al 2010). e Riccia-type sporophyte with no seta and foot, suppression of differentiation of elaters and polyplastidic unlobed sporocyte.…”

“…Monoplastidic and slightly lobed sporocytes occur in Dumortiera and Monoclea (Renzaglia et al 1994;Shimamura et al 2000a), and a close phylogenetic relationship between the two genera is also supported by recent phylogenetic analyses (Forrest and Crandall-Stotler 2005;Heinrichs et al 2005). Monoplastidic and unlobed sporocytes occur in Lunularia, Marchantia, and Wiesnerella (Shimamura et al 2003;Brown et al 2007), while polyplastidic and unlobed sporocytes (apolar sporocytes) occur in disparate members of marchantioid liverworts such as Riella, Sphaerocarpos, Conocephalum, Monosolenium, Riccia, Ricciocarpos and Reboulia (Kelley and Doyle 1975;Lemmon 1988, 2008;Neidhart 1978;Shimamura et al 1998Shimamura et al , 2001. Apolar sporocytes with no indication of pre-meiotic establishment of quadripolarity appear to be an exceptional feature in bryophytes, although it is common condition in flowering plants (Traas et al 1989;Brown and Lemmon 1991).…”