Occurrence of different sites of self-incompatibility reaction in four Anathallis (Orchidaceae, Pleurothallidinae) species

Abstract

Orchids are typically self-compatible, and in this family self-fertilization is usually prevented by pre-pollination barriers. However, genetic self-incompatibility has been found in species of some lineages of the myophilous subtribe Pleurothallidinae. We carried out experimental pollinations to determine the mating systems of four Anathallis species, a representative genus of a large clade of this subtribe. This is one of the few clades of Pleurothallidinae not studied on this subject to date. All four species present strong self-incompatibility, reinforcing previous findings that this mating system is widespread in the Pleurothallidinae. However, the four species showed two different selfincompatibility reactions, one typical of gametophytic self-incompatibility (pollen tubes becoming irregular in their trajectory with variation in diameter and excessive deposition of callose) and the other typical of sporophytic self-incompatibility (absence of pollen grain germination). The two types of self-incompatibility reaction we found are associated with the two previous groups in previous classification systems: the species that showed a reaction similar to gametophytic self-incompatibility used to be included in Pleurothallis subgen. Specklinia sect. Muscosae and the three species that showed a reaction similar to sporophytic self-incompatibility used to be included in Pleurothallis subgen. Acuminatia. Mating system studies have the potential to help elucidate the phylogeny of groups within the Orchidaceae. We suggest that a wider survey of both mating systems and phylogeny is needed to help answer questions on the phylogeny of these groups.

Morphological Type Identification of Self-Incompatibility in Dendrobium and Its Phylogenetic Evolution Pattern

“…Pollen tube growth stopped at different positions in the style or ovary, which is consistent with previous reports in other orchids. For example, pollen tube growth stopped at certain style positions in P. adamantinensis and P. fabiobarrosii , while it stopped at the ovary in Restrepia species, and the pollinia did not germinate in M. infracta , Octomeria , Stelis , and Specklinia [ 2 , 23 , 26 , 27 ]. This suggests that there are a variety of SI determinants in the Orchidaceae, even in Dendrobium .…”

“…In some species, such as Masdevallia infracta , Octomeria , Stelis , Specklinia , and Anathallis spp. (except A. microphyta ), pollen after pollination does not germinate [ 26 ], and self-pollination of 26 species of Restrepia (Orchidaceae) revealed that pollen tubes grow only into the top third of the ovary [ 23 ], while Pleurothallis adamantinensis and P. fabiobarrosii are strictly self-incompatible because pollen tube growth ceases near the base of the style [ 27 ]. We identified two SI species in Dendrobium : Dendrobium longicornu and D. chrysanthum .…”

Effect of polyploidy and pollination methods on capsule and seed set of pansies (Viola × wittrockiana Gams)

“…Such a pattern is also reported from other species, e.g. Chamaecrista keyensis (Liu, Koptur 2003), Impatiens reptans (Tian et al 2004), Dianthus guliae (Gargano et al 2009), Pultenaea villosa (Ogilvie et al 2009) and Anathallis species (Gontijo et al 2010).…”

An investigation of self‐incompatibility within the genus Restrepia

“…this subtribe, cladistic analysis has identifi ed eight main clades (designated A to H), ( Pridgeon and Chase, 2001 ). Other studies have revealed the existence of SI systems operating within seven of the eight clades, with many suggesting a link between SI and myophily ( Christensen, 1992 ;Borba et al, 2002 ;Blanco and Barbosa, 2005 ;Tremblay and Ackerman, 2007 ;Barbosa et al, 2009 ;Gontijo et al, 2010 ;Borba et al, 2011 ). The remaining clade (clade B), which includes the Pleurothallid genus Restrepia , is the only one in which the operation of SI has yet to be confi rmed.…”

“…Although studied in many angiosperm families, SI is often considered relatively rare in the Orchidaceae, with most species being self-compatible and "avoiding" self-pollination by other means ( Agnew, 1986 ;Dressler, 1990Dressler, , 1993Borba and Semir, 1999 ;Singer and Cocucci, 1999 ;Borba et al, 2001 ;Ingrouille and Eddie, 2006 ;Roberts, 2003 ;Gontijo et al, 2010 ). Dressler (1990Dressler ( , 1993 ) estimated SI to occur in 10% of orchid species, but considered its full extent still to be established ( Dressler, 1993 ).…”