Cell Division by Furrowing in Magnolia

Comparative microsporogenesis and anther development of selected species from Magnoliaceae

“…The cytoplasm is partially separated after the first nuclear division by a furrow of callose growing centripetally and orthogonally to the meiotic spindle. In this study, cytokinesis is therefore intermediate between simultaneous and successive, consistent with previous research ( Magnolia tripetala , Farr 1918; Magnolia liliflora , Hayashi 1960; Magnolia soulangeana , Nadot et al 2008; Liriodendron tulipifera , Guzzo et al 1994 and Michelia figo , Hayashi 1966). Cytokinesis is exceptional in Magnolia and has been interpreted as a special case of simultaneous cell division (Nadot et al 2008).…”

“…Isobilateral tetrads are quite common in this family (Hayashi 1960, 1965, 1966, 1984, Kapil and Bhandari 1964, Pan and Gong 2002, Pan et al 2003, Fu et al 2009), and more or less fifty percent of observed microspore tetrads in all species in this survey were isobilateral. Farr (1918) reported that tetrahedral tetrads were exceedingly rare in Magnolia , while decussate tetrads made up for almost 50%. In this study, tetrahedral tetrads constitute thirty percent in M. paneatalauma , while decussate type constitute about 12.9%.…”

“…Of further interest is the accumulation of evidence which may help resolve the supposed plesiomorphic position of the Magnoliaceae. Although much research has been undertaken in microsporogenesis and male gametophyte development of some species of this family (Maneval 1914, Farr 1918, Rau 1930, Hayashi 1960, 1965, 1966, 1984, Kapil and Bhandari 1964, Pan and Gong 2002, Pan et al 2003, Xiao and Yu 2004, Wang et al 2005, Ao 2007, Fu et al 2009), neither descriptions on anther development nor stamen morphological features have been documented in detail (Canright 1952, Endress and Hofford 1989). This present survey provides new observations on microsporogenesis, gametophyte development, anther morphology, structure and development in selected species of Magnoliaceae, and attempts to recognize the evolutionary significance of the androecial features.…”

DEVELOPMENT OF SPORES AND GAMETOPHYTES IN CERTAIN NEW WORLD SPECIES OF SALVIA

“…In this genus the cells are shown to be in close contact. Church (1929) reports cytomyxis as not uncommon in the grasses, and that the condition is attended by ejection of chromatin from the nucleus of one microgametocyte to the cytoplasm of the adjacent cell, and hence the species is not so good an illustration of cytomixis according to the definition first propounded by Gates (1908). According to Church (1929) the nucleolus is concerned in cjrtomixis, for Digby (1909) reported ejections of nucleolar material in Galtonia candicans.…”

Phylogenetic comparative analysis of microsporogenesis in angiosperms with a focus on monocots

“…Other features include the way intersporal walls are formed and the shape of resulting tetrads. Until recently, descriptions of intersporal wall formation were available for a limited number of species only, belonging to the monocots (Waterkeyn, 1962; Chikkannaiah, 1963; Longly and Waterkeyn, 1979; Periasamy and Amalathas, 1991), to basal angiosperms (Farr, 1918; Sastri, 1957, 1962; Hotchkiss, 1958; Hayashi, 1960; Sampson, 1963; Bhandari and Venkataraman, 1968; Sampson, 1969; Dinis and Mesquita, 1993; González et al, 2001; Tsou and Fu, 2002) and to the eudicots (see, for example, Bolenbaugh, 1928; Horner and Lersten, 1971; Albertsen and Palmer, 1979; Blackmore and Barnes, 1988, 1995), bearing in mind that basal angiosperms and eudicots were formerly classified in the dicots. The common view presented in papers or books on embryology was that wall formation occurred via centrifugal cell plates in the case of successive cytokinesis, whereas it occurred by centripetally growing furrows, meeting in the center of the microsporocyte, in the simultaneous situation (Bhojwani and Bhatnagar, 1974; Rangaswamy et al, 2001).…”