Evolution of flower allometry and pigmentation in Mammillaria haageana (Cactaceae)

Abstract

Background A puzzle in evolution is the understanding of how the environment might drive subtle phenotypic variation, and whether this variation is adaptive. Under the neutral evolutionary theory, subtle phenotypes are almost neutral with little adaptive value. To test this idea, we studied the infraspecific variation in flower shape and color in Mammillaria haageana, a species with a wide geographical distribution and phenotypic variation, which populations are often recognized as infraspecific taxa. Results We collected samples from wild populations, kept them in the greenhouse for at least one reproductive year, and collected newly formed flowers. Our first objective was to characterize tepal natural variation in M. haageana through geometric morphometric and multivariate pigmentation analyses. We used landmark-based morphometrics to quantify the trends of shape variation and tepal color-patterns in 20 M. haageana accessions, belonging to five subspecies, plus 8 M. albilanata accessions for comparison as the sister species. We obtained eight geometric morphometric traits for tepal shape and color-patterns. We found broad variation in these traits between accessions belonging to the same subspecies, without taxonomic congruence with those infraspecific units. Also the phenetic cluster analysis showed different grouping patterns among accessions. When we correlated these phenotypes to the environment, we also found that solar radiation might explain the variation in tepal shape and color, suggesting that subtle variation in flower phenotypes might be adaptive. Finally we present anatomical sections in M. haageana subsp. san-angelensis to propose some of the underlying tepal structural features that may give rise to tepal variation. Conclusions Our geometric morphometric approach of flower shape and color allowed us to identify the main trends of variation in each accession and putative subspecies, but also allowed us to correlate these variation to the environment, and propose anatomical mechanisms underlying this diversity of flower phenotypes.

Large flowers can be short‐lived: Insights from a high Andean cactus

“…Neither did the absolute amount of water in day‐ and night‐time harvested PTs differ. The latter could have to do with the fact that the tepals (and hypanthium) of cactus flowers (Erdelská & Ovečka, 2004; Garcia de Almeida et al, 2010; Rosas et al, 2022), like the vegetative body (Nobel et al, 1992), contain mucilage which is comprised of soluble sugars with osmotic properties (Saag et al, 1975) important from drawing water into cells. The apparent lack of functional stomata in cactus flowers (Nobel, 1977), which in the vegetative body open at night in cacti, could be another factor.…”

Correction to: Evolution of flower allometry and pigmentation in Mammillaria haageana (Cactaceae)

“…1186/ s12870-021-03386-8. *Correspondence: urosas@ib.unam.mx 1 Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico Full list of author information is available at the end of the article Author details 1 Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico. 2 Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de Mexico, Mexico City, Mexico.…”