A survey of tricolpate (eudicot) phylogenetic relationships, Walter S. Judd and Richard G. Olmstead.[1]
El posicionamiento de Vitaceae (incluyendo a Leea, a veces ubicado en una familia separada: Leeaceae) no está totalmente clarificado. La familia es posiblemente hermana del resto de las rósidas (Soltis et al., 2000; Kim et al., 2004), pero pertenecería a algún lugar próximo al nexo —pobremente resuelto— de la base de las eudicotiledóneas nucleares (core eudicots) (por ejemplo, Soltis et al., 2003; Hilu et al., 2003). Así, el emplazamiento de Vitaceae en las rósidas según el APG no tendría vigencia.
Crossosomatales, as defined in APG II (2003), contain Crossosomataceae, Stachyuraceae, and Staphyleaceae, and are characterized by a distinctive seed coat, in which the cell walls of the many-layered testa are more or less all lignified. The order possibly could be expanded to include Geossolomataceae, Ixerbaceae, and Strasburgeriaceae, which have a similar testa anatomy (APG II, 2003 ; Stevens, 2003 ).
Geraniales include Geraniaceae and a few small families (APG II, 2003 ) having leaf margins with glandular teeth, vessels with simple perforations, obdiplostemonous flowers with a persistent calyx, and nectaries positioned on the outside of the androecium (Stevens, 2003 ). All of the families of Geraniales sensu Cronquist (1981), except Geraniaceae, are placed elsewhere in APG II (2003).
Myrtales were placed in malvids (eurosids II) in APG (1998), but they were left unplaced within the rosids in APG II (2003). Myrtales, along with Geraniales, are weakly associated with malvids in some studies (e.g., Savolainen et al., 2000b ; Soltis et al., 2003; Hilu et al., 2003), or with fabids in others (e.g., Soltis et al., 2000). Monophyly of Myrtales is indicated by their vessel elements with vestured pits, stems with internal phloem, stipules absent or present only as small lateral or axillary structures, flowers with a short to elongate hypanthium, stamens incurved in bud, and a single style (the carpels being nearly completely connate) and receives strong molecular support (Conti et al., 1996, 1997; Savolainen et al., 2000b; Soltis et al., 2000). Vochysiaceae are sister to Myrtaceae, a family characterized by pellucid dots (with aromatic terpenoids). Lythraceae and Onagraceae are sister, sharing a valvate calyx and grouped vessels in the wood, and Combretaceae are sister to them (Johnson and Briggs, 1984; Conti et al., 1996, 1997; Savolainen et al., 2000b; Soltis et al., 2000, 2003). Melastomataceae are sister to Memecylaceae (Clausing and Renner, 2001), and both have unusual anthers: those of Melastomataceae usually opening by pores and often bearing various appendages and those of Memecylaceae with a resin-secreting gland on the connective. The small families Rhynchocalycaceae, Oliniaceae, Penaeaceae, Alzateaceae, and Crypteroniaceae constitute a clade (Conti et al., 1999 ), the members of which have square stems with more or less swollen nodes, stamens equal in number to and opposite the petals, exotestal cells periclinally elongated, and a nonfibrous endotegmen. Stevens (2003) has suggested that these could be combined.
Embryo length varies considerably, but I have not treated this feature critically enough; Martin (1946) is still a very useful source of basic information, while Baskin and Baskin (1998) add much information on various kinds of dormancy of the seed, linking it with embryo size, etc. In both, speculations on the evolution of embryo size, type, and dormancy, should be treated with caution; Forbis et al. (2002) have recently evaluated embryo size in the context of phylogeny. The length of the embryo is emphasized here; it is not absolute, but is the length of embryo relative to the length of the seed. Long embryos are at least half the length of the mature seed and include cases where the embryo is curved and, when stretched out, is much longer than the seed, medium embryos are about half the length of the seed, short embryos are between one half and about one tenth the length of the seed, while minute embryos are still smaller. The states of this character are arbitrarily delimited. Mangrove taxa, and to a certain extent aquatics in general (e.g. Nymphaeaceae, Ceratophyllaceae, Nelumbonaceae), have large and well-developed embryos, perhaps to ensure rapid establishment of the seedling after it germinates. Of course, that embryos are long does not mean that endosperm is necessarily absent, also, if seeds are minute (the "Micro" type of Martin 1946, see also Baskin & Baskin 1998) their contained embryos necessarily will be minute in absolute size, although by the criterion of relative length they might well be long... The embryos of such very small seeds are often undifferentiated (see below, Embryo morphology), while "minute" embryos as defined above often require a period after dispersal for maturation to be completed (morphological dormancy); even if they have cotyledons, etc., they will have to grow to fill up the inside of the seed before germination begins (see also Forbis et al. 2002).
EUROSID I: endosperm scanty.
Endosperm presence/absence refers to the situation in the ripe seed, however, it can be a difficult character to deal with. Endosperm is very nearly always found in the very young embryo, but whether or not it persists is of interest here. There is of course a continuum between scanty and copious endosperm, and even the absence of endosperm is by no means as distinct a state as it might appear. Other endosperm variants, such as ploidy levels other than triploid are mentioned as they occur. Only Viscum and its relatives (Santalaceae) have a green, chlorophyllous endosperm.
Details of seed coat anatomy are taken especially from Corner (1976), Krach (1976), Takhtajan (editor: 1985, 1988, 1991, 1992, 2000), Danilova (editor: 1996), Werker (1997), and Bouman and his collaborators (e.g. Bouman & Boesewinkel 1997); see also Batygina (2006). As Wunderlich (1967a), Corner (1976), G. Dahlgren (1991) and many others have emphasized, variation in seed coat anatomy is of considerable systematic interest. Fortunately, details of seed coat anatomy can often be observed in hand sections that are stained for lignin, however, which cells are testal and which tegmic in origin can be difficult to see in the mature coat. The testa develops from the outer integument and the tegmen from the inner integument. The prefixes exo- meso- and endo- refer to tissues developing from the outer epidermis, the middle part, and inner epidermis respectively of either the testa or tegment (Corner 1976; see also Schmid 1986). The shape, lignification and inclusions of the cells in these layers is of interest, in particular, much attention has been paid to which part of the seed coat forms the protective or mechanical layer. A malpighian layer of vertically elongated and much thickened cells is quite common, although varying in origin (Werker 1997); it is often a systematically important character. A vascularised (see ovule variants above) and multiplicative testa and/or tegmen (see integument thickness), the latter with the number of cell layers increasing after fertilization, are mentioned only when they occur. In drupe-, achene- or nut-type fruits in particular the seed coat is often undistinguished at maturity and systematically uninformative, the protective function of the seed coat being carried out by the fruit wall. Seed coat anatomy of saprophytes (Bouman et al. 2002) and parasites also may be of little use in detecting relationships since the seeds of such plants are often very reduced, light, and dispersed by wind. Distinctively thickened transfer cells may be found in various places in the seed coat (see e.g. Boraginaceae) or embryo. For a survey of mucilages and gums in seeds, see Grubert (1981). Some monoocts have distinctive substances associated with the testa, in particular, the black phytomelan and brownish phlobaphene; the former is also found in some Asteroideae, and is a inert and very resistant compound lacking nitrogen rather like green tea polyphenolics and probably derived from catechol (see especially Graven et al. 1998 for what is known about its chemistry [not very much], etc.; Rasmussen et al. 2006).
FABALES + ROSALES + CUCURBITALES + FAGALES: (N-fixing by root-dwelling associates [usu. the actinomycete Frankia]); seed exotestal; endosperm at most scanty, embryo large.
Nitrogen fixation. Angiosperms that can fix nitrogen in association with bacteria are uncommon, yet are found almost exclusively in a group of four orders, the N-fixing clade (Fabales, Rosales, Cucurbitales, Fagales). Jeong et al. (1999) and Clawson et al. (2004) discuss this association in the context of the evolution of Frankia, the bacterium most commonly involved outside the Fabaceae.
Me parece que este término no está muy bien traducido, dado que "core" hace función de atributo de "Eudicots" y se pierde el sentido original, que es "Eudicotiledóneas nucleares". No debemos caer en el error de traducir una abreviatura coloquial americana, Eudicots (porque les resulta muy largo Eudicotyledons), por Eudicotas. Procuremos escribir Wikipedia en español y no en spanglish, gracias, y ánimo. --DryasHáblame quedo al carpelo 19:02 24 feb 2007 (CET)
Entiendo tu explicación, salvo porque ¿qué tienen de nucleares las eudicotiledóneas?
La traducción vien al hecho de entender que el "core eudicots" es un nodo que aglutina varios grupos, entendido así, ese nodo sería un núcleo de eudicotas, esto es un punto central interno (core) del que parten varios clados conjuntamente comprendidos como eudicotiledoneae. Esta es la forma en la que yo lo interpreté ¿esto es incorrecto? por favor, comenta y critica.
Otra cosa es "eudicotas nucleares": ¿debo entender que es "nuclear" por "basal", en referencia al grupo?
De todas formas, el uso es la regla, si ya es de uso corriente "eudicotiledoneas nucleares", es la denominación que hay que usar aquí.
Dryas por favor ayudame que ahora se me fizo una ensalada en la cabeza... XoD --musicantor 20:10 24 feb 2007 (CET)
El adjetivo "nuclear" significa "relativo o perteneciente al núcleo", pero no necesariamente al del átomo, sino al de cualquier cosa que lo tenga. Según esta visión, las eudicotiledóneas que son tales, sin ningún lugar a dudas, forman el "núcleo". Lo contrario serían las "basales", es decir, aquellas que son eudicotiledóneas, pero primitivas, y sin presentar los caracteres "puros" del "núcleo" (en particular, no ser siempre tricolpadas). Está muy claro en el artículo Eudicotiledóneas: son eudicotiledóneas basales las Sabiales, Buxales, Trochodendrales, Ranunculales, Proteales y Gunnerales (aunque esto no lo has dejado claro). Las demás son "Eudicotiledóneas nucleares". Mira la detallada explicación en la web de la APG. No he visto la expresión en castellano en ningún libro aún, por lo que, si quieres, puedes dejarlo como está. Sólo quería llamr tu atención sobre una expresión que me parece mal traducida. Un cordial saludo, --DryasHáblame quedo al carpelo 23:17 26 feb 2007 (CET)
19:02 24 feb 2007 (CET)
23:17 26 feb 2007 (CET)