The best of both worlds: Apomixis and sexuality co‐occur in species of Microlicia, Melastomataceae. Issue 3 (13th April 2021)

• Record Type: Journal Article
• Authors: Viana, Matheus Lacerda; Oliveira, Paulo Eugênio; Romero, Rosana; Caetano, Ana Paula Souza
• Is Part Of: Plant species biology. Volume 36:Issue 3(2021)
• Page Start: 476
• Page End: 488
• Publication Date: 2021-04-13
• Subjects: adventitious embryony -- apomictic species -- apospory -- pollen development -- polyembryony; Plants -- Evolution -- Periodicals; Plants -- Classification -- Periodicals; 581
• DOI: 10.1111/1442-1984.12330
• Languages: English
• ISSNs: 0913-557X

Abstract

Abstract: Apomixis, the asexual formation of embryos and seeds, occurs in approximately 18% of angiosperm families. Melastomataceae exhibits a remarkable number of apomictic species, distributed among different tribes. This mode of reproduction has been elucidated in Miconieae, but remains unclarified for other groups, such as Microlicieae. Although apomixis has been previously described for Microlicieae species, the cytological basis for this phenomenon is entirely unknown in this group. Thus, populations of Microlicia fasciculata and M. polystemma were used in order to (a) investigate the presence of autonomous apomixis; (b) verify if this mode of reproduction leads to polyembryony; and (c) investigate whether apomixis may occur in parallel with the sexual process. We tested these species for autonomous fruit set and polyembryony, and pollen viability, and analyzed pollen tube growth. Anatomical techniques were used to elucidate the micro‐ and megasporogenesis and gametogenesis. The species showed autonomous fruit and seed formation and exhibited polyembryony. Apospory and adventitious embryony were the developmental mechanisms of apomixis in M. fasciculata and M. polystemma, respectively. Both species exhibited low pollen viability. However, some viable pollen, reduced embryo sac formation, natural pollination and pollen tube growth enable sexual reproduction and characterize these species as facultative apomicts. The independence of pollinators for fruit set, uniparental reproduction and the possibility of sexual reproduction, confer reproductive assurance and flexibility, bringing together advantages of sexual and asexual reproduction. In this sense, apomixis may have played an important role in the evolution and diversification of Microlicia, a widely distributed genus in the Brazilian Cerrado. Abstract : Autonomous apomixis and the formation of polyembryonic seeds were described in Microlicia fasciculata and M. polystemma, Microlicieae, Melastomataceae. Although both species exhibited low pollen viability, a certain amount of viable pollen, the formation of reduced embryo sacs, and the occurrence of natural pollination enable sexual reproduction events, characterizing these species as facultative apomicts. The independence of pollinators for fruit set, uniparental reproduction, and the possibility of sexual reproduction can confer reproductive assurance and flexibility to these species.