Reproductive biology as a tool to elucidate taxonomic delimitation: How different can two highly specialized subspecies of Parodia haselbergii (cactaceae) be?

Autor: Becker R; Laboratory of Systematics of Vascular Plants, Botany Department, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91509-900, Rio Grande do Sul, Brazil. beckerr92@gmail.com., Pittella R; Laboratory of Systematics of Vascular Plants, Botany Department, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91509-900, Rio Grande do Sul, Brazil., Calderon-Quispe FH; Laboratory of Systematics of Vascular Plants, Botany Department, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91509-900, Rio Grande do Sul, Brazil., de Moraes Brandalise J; Laboratory of Systematics of Vascular Plants, Botany Department, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91509-900, Rio Grande do Sul, Brazil., Farias-Singer R; Porto Alegre Botanical Garden, Secretaria Estadual do Meio Ambiente do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil., Singer RB; Laboratory of Systematics of Vascular Plants, Botany Department, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, Porto Alegre, 91509-900, Rio Grande do Sul, Brazil.
Jazyk: angličtina
Zdroj: Journal of plant research [J Plant Res] 2024 Sep; Vol. 137 (5), pp. 863-875. Date of Electronic Publication: 2024 Jul 10.
DOI: 10.1007/s10265-024-01555-y
Abstrakt: Reproductive isolation is one of the mechanisms of speciation. The two currently accepted subspecies of Parodia haselbergii (P. haselbergii subsp. haselbergii and P. haselbergii subsp. graessneri) were studied regarding flower traits, phenology, breeding systems and pollination. In addition, a principal component analysis with 18 floral characters and germination tests under controlled conditions were performed for both taxa. Pollination was studied in the field, in two localities of Southern Brazil. Pollinators were recorded through photos and film. Breeding system experiments were performed by applying controlled pollinations to plants excluded from pollinators. Both taxa mostly differ in asynchronous flowering periods, floral traits (including floral part measurements and nectar concentration) and pollinators. The flowers of both subspecies are functionally protogynous and perform remarkably long lifespans (≥ 15 days), both traits being novelties for Cactaceae. Whereas the reddish flowers of P. haselbergii subsp. haselbergii (nectar concentration: ca. 18%) are pollinated by hummingbirds of Thalurania glaucopis, the greenish flowers of P. haselbergii subsp. graessneri (nectar concentration: ca. 29%) are pollinated by Augochlora bees (Halictidae). Both subspecies are self-compatible, yet pollinator-dependent. The principal component analysis evidenced that both subspecies are separated, regarding flower traits. The seeds of both subspecies performed differently in the germination tests, but the best results were recovered at 20 °C and germination considerably decreased around 30 °C. In conclusion, all these results support that both taxa are in reproductive isolation, and can be treated as different species.
(© 2024. The Author(s) under exclusive licence to The Botanical Society of Japan.)
Databáze: MEDLINE
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