Sporoderm ontogeny in Cabomba aquatica (Cabombaceae)

Sporoderm development inSwida alba(Cornaceae), interpreted as a self-assembling colloidal system

“…Similar twining spirals were shown around columellae in the mature exine of Cabomba aquatica DC. after oxidative degradation (Gabarayeva et al, 2003). The appearance of cylindrical micelles is preceded by columns of spherical micelles (see, for example, Figure 3C), as was observed also in sporoderm development of Chamaedorea microspadix Burret (Gabarayeva & Grigorjeva, 2010).…”

Early evolution of angiosperm pollen as inferred from molecular and morphological phylogenetic analyses

“…Lactoris: Zavada & Taylor (1986), Sampson (1995Sampson ( , 2000a; all showed large granules sometimes fused into irregular columellae (1), a thin nexine, and no visible endexine or foliations. Cabombaceae: Walker (1976b), Osborn et al (1991), Gabarayeva et al (2003). See text for discussion of infratectal structure.…”

“…In Cabomba and Brasenia, Osborn et al (1991) illustrated a thin nexine with no clear signs of lamellae; they interpreted a layer in Brasenia that Thanikaimoni (1985) identified as lamellated endexine as part of the intine or an artifact. In Cabomba, Gabarayeva et al (2003) described deposition of a thin darker endexine on the inside of the foot layer, separated from it by a white line. Osborn et al (1991) also showed an inner dark layer, but judging from their figures it disappears after acetolysis.…”

“…In Cabombaceae, the columellae are irregular and branch apically, giving the impression in some sections that they break down into granules, but they are fairly columnar for most of their length (Osborn et al 1991). Gabarayeva et al (2003) showed that their peculiar morphology is a result of origin by lateral fusion of probacula. The degree of irregularity is comparable to that in Austrobaileya, previously scored as columellar, where columellae vary in shape and thickness (Endress & Honegger 1980, Zavada 1984, or in Trimenia, where Sampson (2000a) described the innermost tectum, columellae, and foot layer as sometimes having a ''partly granular form.''…”

“…However, it would have to become thinner and lose its conspicuous laminations in the extra-apertural areas. Endexine was later lost in several lines, such as Cabombaceae, Chloranthaceae, and Saururaceae, where significantly there are occasional reports of an inner layer of uncertain homology that may be a vestige of endexine (Walker 1976b, Chlonova & Surova 1988, Doyle & Hotton 1991, Osborn et al 1991, Sampson 2000a, Gabarayeva et al 2003see Material and Methods).…”