The presence of throat hair increased the number of pollen grains remaining in the flowers (A) and decreased the proportion of pollen removed (B) in single visits by halictid bees.

<p>“HR” and “C” indicate hair-removal (white bar) and control groups (black bar), respectively. Significant differences at the 0.001 level are indicated by “***”. Numbers in brackets are sample sizes. Bars indicate standard errors.</p

Floral traits of <i>Cyananthus delavayi</i> and its pollinator in the natural population.

<p>A: Dissected view of perfect flowers, showing long throat hair (TH) and pollen presentation area (PP); B: Dissected view of female flowers, showing short throat hair and exerted stigma; C: Pollen-collecting <i>Halictus</i> sp. crawling into a perfect flower in the male phase. A and B are modified from [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117149#pone.0117149.ref020" target="_blank">20</a>]. All pictures are photographed by Yang Niu.</p

A Sexually Dimorphic Corolla Appendage Affects Pollen Removal and Floral Longevity in Gynodioecious <i>Cyananthus delavayi</i> (Campanulaceae)

<div><p>The floral traits of bisexual flowers may evolve in response to selection on both male and female functions, but the relative importance of selection associated with each of these two aspects is poorly resolved. Sexually dimorphic traits in plants with unisexual flowers may reflect gender-specific selection, providing opportunities for gaining an increased understanding of the evolution of specific floral traits. We examined sexually dimorphic patterns of floral traits in perfect and female flowers of the gynodioecious species <i>Cyananthus delavayi</i>. A special corolla appendage, the throat hair, was investigated experimentally to examine its influences on male and female function. We found that perfect flowers have larger corollas and much longer throat hairs than female flowers, while female ones have much exerted stigmas. The presence of throat hairs prolonged the duration of pollen presentation by restricting the amount of pollen removed by pollen-collecting bees during each visit. Floral longevity was negatively related to the rate of pollen removal. When pollen removal rate was limited in perfect flowers, the duration of the female phases diminished with the increased male phase duration. There was a weak negative correlation between throat hair length and seed number per fruit in female flowers, but this correlation was not significant in perfect flowers. These results suggest that throat hairs may enhance male function in terms of prolonged pollen presentation. However, throat hairs have no obvious effect on female function in terms of seed number per fruit. The marked sexual dimorphism of this corolla appendage in <i>C. delavayi</i> is likely to have evolved and been maintained by gender-specific selection.</p></div

Biconcave and Convex–Concave Tribenzotriquinacene Dimers

A new chiral tribenzotriquinacene bearing an ortho-bromoaniline nucleus was synthesized and optically resolved. The individual enantiomers, the absolute configuration of which was confirmed by single-crystal X-ray structure analysis, were stereoselectively converted into the same pyrazine-fused syn-bis-TBTQ derivative by chirality-assisted Buchwald–Hartwig amination. The corresponding diastereomeric anti-dimer was obtained alongside the syn-dimer from the racemic sample under similar reaction conditions. X-ray structure analysis of the dimers confirmed the mutual biconcave and convex–concave configuration of their TBTQ moieties and the preservation of the orthogonal orientation of the indane wings within each of them

The Pearson correlation between throat hair length and seed number per fruit.

<p>The correlation was not significant in perfect flowers (A) but marginal significant in female flowers (B).</p

Kinetic analysis of VvFrsA with pNPA as substrate.

The initial velocities were determined as function of pNPA substrate concentrations with the concentration of VvFrsA fixed at 9.5 μM in the buffer of 50 mM PBS, pH 7.5.</p

Pollen removal and throat hair manipulation had significant effects on floral longevity in perfect flowers.

<p>Black, white and gray bars represent male, neutral and female phases, respectively. Solid circles represent the proportion of male phase duration (male phase divided by total floral longevity). Along the X-axis, 100% PR, 50% PR and 0% PR indicate pollen completely removed, 50% pollen removed and no pollen removed, respectively (these groups had pollinators excluded); NHR indicates the hair-removal group covered by netting; HR and C indicate hair-removal and natural control groups open to pollinators, respectively. Different lower-case letters above the bars indicate significant differences in total floral longevity at the 0.01 level. Different capital letters on the black bars indicate significant differences in male phase duration (and also in the proportion of male phase) at the 0.01 level. Numbers in brackets are sample sizes. Bars are standard errors.</p

Biconcave and Convex–Concave Tribenzotriquinacene Dimers

A new chiral tribenzotriquinacene bearing an <i>ortho</i>-bromoaniline nucleus was synthesized and optically resolved. The individual enantiomers, the absolute configuration of which was confirmed by single-crystal X-ray structure analysis, were stereoselectively converted into the same pyrazine-fused <i>syn</i>-bis-TBTQ derivative by chirality-assisted Buchwald–Hartwig amination. The corresponding diastereomeric <i>anti</i>-dimer was obtained alongside the <i>syn</i>-dimer from the racemic sample under similar reaction conditions. X-ray structure analysis of the dimers confirmed the mutual biconcave and convex–concave configuration of their TBTQ moieties and the preservation of the orthogonal orientation of the indane wings within each of them

Biconcave and Convex–Concave Tribenzotriquinacene Dimers

A new chiral tribenzotriquinacene bearing an <i>ortho</i>-bromoaniline nucleus was synthesized and optically resolved. The individual enantiomers, the absolute configuration of which was confirmed by single-crystal X-ray structure analysis, were stereoselectively converted into the same pyrazine-fused <i>syn</i>-bis-TBTQ derivative by chirality-assisted Buchwald–Hartwig amination. The corresponding diastereomeric <i>anti</i>-dimer was obtained alongside the <i>syn</i>-dimer from the racemic sample under similar reaction conditions. X-ray structure analysis of the dimers confirmed the mutual biconcave and convex–concave configuration of their TBTQ moieties and the preservation of the orthogonal orientation of the indane wings within each of them

Effects of pH and temperature on hydrolytic activity of VvFrsA.

A. pH dependence of VvFrsA. The assays were carried out with 1 mM pNPA as substrate and 3.8 μM VvFrsA in various buffer at room temperature. B. Temperature effect on activity of VvFrsA. The assays were carried out with 1 mM pNPA as substrate and 2.0 μM VvFrsA in the buffer of 50 mM CHES, pH 9.0. The reaction was quenched after 10 min. Experiments were repeated three times.</p