A compendium of vivipary in the Cactaceae: new reports, data, and research prospects

This review examines the historical research progress and areas of vivipary currently investigated in the Cactaceae. Vivipary, a rare attribute, has evolved multiple times in numerous plant lineages; however, a complete understanding of this event is still lacking in the cactus family and plants, in general. This literature search combines the results obtained from scientific sources addressing aspects of vivipary published since 1900 to 2000, with an emphasis from 2000 to 2021. This systematic compendium summarizes findings in various aspects of vivipary, such as the taxonomic and ecological range, offspring survival, and the physiological bases of this phenomenon in the Cactaceae. To date, 77 viviparous taxa circumscribed in subfamilies Pereskioideae and Cactoideae are known, representing approximately 5.4% vivipary at the family level. The taxonomic and geographic occurrence of this facultative reproductive attribute is discussed along with new reports, subsistence of viviparous and non-viviparous progeny, and a framework examining the phylogenetic distribution and putative origin of this generative mode in the family. The portrayal of the geographic distribution of viviparous species highlights the ubiquity of this trait and identifies vivipary hot spots in Cuba, the Brazilian Mata Atlântica, and NW Mexico, emphasizing ideas for cactus conservation. New data dealing with the role of the phytohormones abscisic acid and gibberellic acid in vivipary is examined in conjunction with the thermoregulatory properties of the fleshy viviparous fruits. Research areas deserving further studies are examined and several model species to conduct multidisciplinary research related to cactus vivipary in different areas of the Americas are proposed.