Genetic structure is associated with phenotypic divergence in floral traits and reproductive investment in a high-altitude orchid from the Iron Quadrangle, southeastern Brazil

Variation in floral volatiles across time, sexes, and populations of wind-pollinated Schiedea globosa

PREMISE

Floral scent is a key aspect of plant reproduction, but its intraspecific variation at multiple scales is poorly understood. Sexual dimorphism and temporal regulation of scent can be shaped by evolution, and interpopulation variation may be a bridge to species differences. We tested whether intraspecific chemical diversity in a wind-pollinated species where selection from biotic pollination is absent is associated with genetic divergence across the Hawaiian archipelago.

METHODS

Floral volatiles from females, males, and hermaphrodites of subdioecious Schiedea globosa grown in a common environment from 12 populations were sampled day and night and analyzed by gas chromatography-mass spectrometry. Variation among groups was analyzed by constrained ordination. We also examined the relationships of scent dissimilarity to geographic and genetic distance between populations.

RESULTS

Flowers increased total emissions at night through higher emissions of several ketones, oximes, and phenylacetaldehyde. Females emitted less total scent per flower at night but more of some aliphatic compounds than males, and males emitted more ketones and aldoximes. Scent differed among populations during day and night. Divergence in scent produced at night increased with geographic distance within 70-100 km and increased with genetic distance for males during the day and night, but not for females.

CONCLUSIONS

Schiedea globosa exhibits diel and sex-based variation in floral scent despite wind pollination and presumed loss of biotic pollination. In males, interpopulation scent differences are correlated with genetic differences, suggesting that scent evolved with dispersal within and across islands.

Molecular characterization of endangered Iranian terrestrial orchids using ISSR markers and association with floral and tuber-related phenotypic traits

We aimed to study the genetic diversity, population structure, and phylogeny of Iranian orchids using inter-simple sequence repeat (ISSR) markers to find markers associated with phenotypic traits. Based on the phenotypic analysis, the inflorescence length and the flower number of studied accessions ranged from 3.92 to 27.13 cm and 5 to 50, respectively. On the other hand, the tuber length ranged from 1.80 to 9.35 cm. A total of 310 reproducible ISSR fragments with a size range of 150 to 3000 bp were amplified. ISSR primers provided an average polymorphism information content of 0.391, varied from 0.488 for UBC-876 to 0.351 for UBC-842. Os.J population showed the lowest genetic diversity (H = 0.057 and I = 0.075), while Oyst.JA population showed the highest genetic diversity (H = 0.114 and I = 0.158). At species level, the average coefficient of genetic differentiation (G ST) ranged from 0.265 for Orchis simia to 0.587 for Himantoglossum affine. Gene flow (Nm) varied from 1.38 (O. simia) to 0.756 (Anacamptis collina). The UPGMA genetic similarity dendrogram using Jaccard coefficients (r = 0.973) revealed six main clusters. Based on the Bayesian clustering method, the highest probability of the data was achieved when accessions were divided into eight groups. Floral and tuber-related phenotypic traits represented high correlations together, and they were associated with some ISSR bands based on the multiple association analysis. Altogether, ISSR markers proved to be useful for discrimination and clarification of the relationships among species and populations collected from geographically different locations. Furthermore, it could identify the polymorphism among accessions within each population and species.

SUPPLEMENTARY INFORMATION

The online version of this article (10.1007/s12298-020-00920-0) contains supplementary material, which is available to authorized users.

Morphological and Genetic Diversities of Habenaria radiata (Orchidaceae) in the Kinki Area, Japan

Floral organs have evolved from leaves for reproduction, and the morphological analyses help to understand the plant diversity and evolution. Habenaria radiata (syn. Pecteilis radiata) is a terrestrial orchid living in wetlands in Japan, Russia, South Korea, and China. The habitats of this plant in Japan have been reduced because of environmental destruction and overexploitation, and thus it is on the Red List of Japan as a Near Threatened species. One of the three petals of the H. radiata flower is called a lip or labellum, which resembles a flying white bird, egret, or white heron, with its proposed function being to attract pollinators. To understand the diversity of H. radiata plants in different areas, we examined the lip morphology and phylogeny of populations from eight habitats in the Kinki area, Japan. The complex shapes of the lips were quantified and presented as a radar chart, enabling characterization of the morphological difference among populations. Phylogenetic analysis with microsatellite markers that we generated showed the variation of genetic diversity among populations, suggesting the different degrees of inbreeding, outbreeding, and vegetative propagation. Our approach offers a basic method to characterize the morphological and genetic diversity in natural populations.