
Figure 1: Common views of some studied plants with blue color in April of 2024 just after the snow missed
Species | Trivial name | Family | Species | Trivial name | Family |
Adoxa moschtellina L. | Muskuskruid | Viburnaceae | Galium verum L. * | Bed straw | Rubiaceae |
Allium oleraceum L. | Field garlic | Alliaceae | Hylotelephium maximum L. (Holub.) | Stonecrop, orpine,live-for-ever | Crassulaceae |
Anthriscus sylvestris L. | Wild chervil, cow parsley | Umbelliferae | Phlomoides (Phlomis) tuberosa L. | Jerusalem sage | Lamiaceae |
Artemisia campestris L.* | Wormwood field , sage-brush | Asteraceae | Saponaria officinalis L. * | Soapwort | Cariophyllaceae |
Centaurea phrygia L. | Swiss centaury, knapweed | Asteraceae | Scabiosa ochroleuca L. | Cream pincushions, morning bride, scabious | Cariophyllaceae |
Centaurea scabiosa L. | Greater knapweed, cornflower | Asteraceae | Sedum acre L. | Wall pepper | Crassulaceae |
Eryngium planum L. | Sea-holly planum, blue-headed flat-leaf | Umbelliferae | Tanacetum vulgare L.** | Ordinary tansy | Asteraceae |
Euphorbia virgata Waldst. et Kit. | Spurge | Euphorbiaceae | Thalictrum minor (minus) L | Meadow rue | Ranunculaceae |
Festuca pratensis L. | Fescue | Poaceae | |||
Filipendula vulgaris Hill.* | Dropwort | Rosaceae |
Table 1: Studied plant species with blue or silver color of leaves. * and ** folk and medicinal
Species | Month of observation | Maxima, nm | Optical density in maximum, nm | Species | Month of observation | Maxima, nm | Optical density in maximu m, nm | ||
Adoxa moschtellina L. | April | upper | No | Filipendula vulgaris Hill. | April | upper | No | ||
lower | 606 | 0.0905 | lower | No | |||||
May | upper | No | May | upper | No | ||||
lower | No | lower | No | ||||||
June | upper | 595 | 0.0589 | June | upper | 585 | 0.580 | ||
lower | 580 | 0.0525 | lower | 599 | 0.457 | ||||
Allium oleraceum L. | April | upper | No | Gailium verum L. | April | upper | No | ||
lower | 617 | 0.0405 | lower | No | |||||
May | upper | 596 | 0.0512 | May | upper | 594 | 0.0596 | ||
lower | No | lower | No | ||||||
June | upper | No | June | upper | No | ||||
lower | No | lower | No | ||||||
Anthriscus sylvestris L. | April | upper | 586 | 0.0478 | Hylotelephium maximum L. (Holub.) | April | upper | No | |
lower | 599 | 0.0478 | lower | No | |||||
May | upper | No | May | upper | No | ||||
lower | No | lower | 588 | 0.069 | |||||
June | upper | 599-600 | 0.0657 | June | upper | 593 | 0.0598 | ||
lower | 580 | 0.0623 | |||||||
590 | 0.0576 | lower | 602 | 0.0517 | |||||
595 | 0.0725 | 620 | 0.0598 | ||||||
Artemisia campestris L. | April | upper | 599 | 0.0516 | Phlomoides (Phlomis) tuberosa L. | April | upper | 611 | 0.044 |
616 | 0.0696 | lower | 598 | 0.0276 | |||||
lower | No | May | upper | No | |||||
May | upper | 578 | 0.0661 | lower | 609 | 0.0615 | |||
lower | 579 | 0.0401 | June | upper | No | ||||
June | upper | No | lower | No | |||||
lower | No | ||||||||
Centaurea phrygia L. | April | upper | No | Saponaria officinalis L. | April | upper | 620-621 | 0.568 | |
lower | No | lower | No | ||||||
May | upper | 593 | 0.0880 | May | upper | No | |||
lower | 611 | 0.0780 | lower | No | |||||
June | upper | June | upper | 602 | 0.0708 | ||||
lower | lower | 628 | 0.0700 | ||||||
Centaurea scabiosa L. | April | upper | No | Scabiosa ochroleuca L, | April | upper | No | ||
lower | No | lower | No | ||||||
May | upper | No | May | upper | No | ||||
lower | 586 | 0.0662 | lower | No | |||||
June | upper | 579 | 0.0670 | June | upper | 592 | 0.0636 | ||
lower | 593 | 0.0665 | lower | 599 | 0.0598 | ||||
Erytrigiumplanum L. | April | upper | No | Sedum acre L. | April | upper | No | ||
lower | 598 | 0.0478 | lower | No | |||||
May | upper | 591 | 0.0580 | May | upper | 621 | 0.0628 | ||
lower | No | lower | No | ||||||
June | upper | 598 | 0.0619 | June | upper | No | |||
lower | 592 | 0.0838 | lower | No | |||||
Euphorbia virgata Waldst. et Kit. | April | upper | No | Tanacetum vulgare L. A | April | upper | No | ||
lower | No | lower | 618 | 0.0636 | |||||
May | upper | 600 | 0.0652 | May | upper | No | |||
610 | 0.0636 | lower | 618 | 0.0457 | |||||
lower | No | June | upper | 617 | 0.0597 | ||||
June | upper | 618 | 0.0602 | ||||||
lower | 586 | 0.0819 | lower | ||||||
Festuca pratensis L. | April | upper | 600 | 0.529 | Thalictrum minor L. | April | upper | No | |
lower | No | ||||||||
May | upper | No | May | upper | No | ||||
lower | No | ||||||||
June | upper | No | June | upper | No | ||||
lower | 590 | 0.0563 |
Table 2: Maxima in the absorption spectra of the studied plants. Significant optical density values (above 0.05) are highlighted in bold. The average error for optical density units was less than 10 percent.
Figure 1: Common views of some studied plants with blue color in April of 2024 just after the snow missed
Figure 2: The absorbance spectra of the surface of the leaf of musk weed Adoxa moschtellina in April (the first derivative of curves to identify maxima). The area of azulenes without noticeable maxima is highlighted with a parenthesis (a - upper side of leaf). The recorded maxima of azulenes are marked with circles, and the maximum of chlorophyll is shown with asterisks (b - lower side of leaf). The absorption spectra (a, b) were compared with the spectrum of a blue crystal (c) of artificially synthesized azulene (“Fluka”, Germany).
Figure 3: Spectral analysis of the leaves of Centaurea phrygia in May. (a) The absorbance spectra (the first derivative of the curves for detecting maxima) in May. The maxima of azulenes are marked with circles, and the maximum of chlorophyll is marked with asterisks. The azulene region without noticeable maxima is highlighted by a parenthesis; (b) and (c) – The absorbance and fluorescence spectra of 10 minute extracts with ethanol (leaf weight/volume 1 :10).
Figure 4: Seasonal dynamics of azulene content (in mg/g of fresh mass) in 10-minute ethanol extracts (leachates) from plant leaves depending on the time of collection, 1 - collection on April 13, 2 –collection on April 29, - 3 from May 13, - 4 from June 1 and 5 from June 11, 2024
Figure 5: The concentration of azulenes in 24-hour ethanol extracts in May (m) and June(s) from the studied plants minus the data of 10-minute extracts related to surface blue pigments. These data for azulenes can be considered as the content of azulenes inside.
Tables at a glance
Figures at a glance