Some features of cultivating different Chamaenerion angustifolium (L.) Scop. forms in vitro

Received: June 9th, 2021 ; Accepted: November 8th, 2021 ; Published: November 15th, 2021 ; Correspondence: [email protected] angustifolium (L.) Scop. characterized by a wide range of economically useful properties. White-flowered form of Ch. angustifolium (L.) Scop. Is extremely rare in nature. At the same time, it is promising as a source of biologically active substances and as a highly decorative plant. The optimal way to reproduce this form is clonal micropropagation. Methods for obtaining Ch. angustifolium in vitro were developed, as well as the optimal selection timing of starting material for micropropagation was determined. In addition, the effect of a mineral composition of nutrient medium and plant growth regulators on the regeneration of microshoots was studied. The highest values of morphometric parameters were achieved on MS medium (Murashige & Skoog, 1962) supplemented with 0.5 mg L-1 BAP. The multiplication factor of the lilac–flowered form was 8.4 ± 0.2, of the white-flowered form - 9.2 ± 0.6. Comparative analysis of morphometric parameters during cultivation of Ch. angustifolium showed no significant difference between the lilac-flowered and white-flowered forms. The effect of antioxidants on the growth and development of regenerants has been shown. The most optimal nutrient medium for clonal micropropagation of the lilac-flowered form was MS medium (Murashige & Skoog, 1962) containing 0.5 mg L-1 of BAP, 50 mg L-1 of ascorbic acid and 50 mg L-1 of citric acids and for micropropagation of the white–flowered form it was the medium, containing 100 mg L-1 PVP

Assessment of essential oil yield in three mint species in the climatic conditions of Central Russia

Received: March 23rd, 2021 ; Accepted: June 9th, 2021 ; Published: June 30th, 2021 ; Correspondence: [email protected], [email protected] aim of the study was to study the harvest time for the essential oil yield and its qualitative composition in three species of mint Mentha piperita L. (Peppermint), M. spicata L. (Spearmint) and M. arvensis var. piperascens Malinv. ex. Holmes (Sakhalinmint). In 2018, the research was performed with plants of second year of vegetation in the Laboratory of Plant Physiology and Immunity of the NV Tsitsin Main Botanical Garden of the RAS. As a result, it was found that the optimal harvest period for Sakhalinmint and Peppermint should be recommended in a phase of mass flowering: the yield of fresh raw materials was 509–479 g m-2 , air-dry raw materials - 110–107 g m-2 ; the content of essential oil in the aboveground part (a mixture of leaves and inflorescences) of plants - 3.24–4.01%; the proportion of the main component of essential oil (menthol) - 57.3–50.2%. In Spearmint, the optimum time for harvesting is the phase of budding. The content of the main component of essential oil (carvon) was maximum - 67.9%, and the yield of essential oil was 2.6%, while the yield was 381 g m-2 of fresh raw materials (81.9 g m-2 of air-dry raw materials) at harvesting in this ontogenesis stage. Analysis of the secretory apparatus parameters on a surface of some green tissues in three mint species showed that the maximum density of secretory glands on both sides of the leaf is characteristic of peppermint, which provides a higher yield of essential oil in this type of mint. The study allowed determining the optimal harvesting time for highly productive mint species when they are grown in the conditions of Central Russia. The raw materials of these mint species can be used for the production of essential oils and are of interest for pharmacology and the perfume and cosmetics industry

New precise determination of the \tau lepton mass at KEDR detector

The status of the experiment on the precise $\tau$ lepton mass measurement running at the VEPP-4M collider with the KEDR detector is reported. The mass value is evaluated from the $\tau^+\tau^-$ cross section behaviour around the production threshold. The preliminary result based on 6.7 pb$^{-1}$ of data is $m_{\tau}=1776.80^{+0.25}_{-0.23} \pm 0.15$ MeV. Using 0.8 pb$^{-1}$ of data collected at the $\psi'$ peak the preliminary result is also obtained: $\Gamma_{ee}B_{\tau\tau}(\psi') = 7.2 \pm 2.1$ eV.Comment: 6 pages, 8 figures; The 9th International Workshop on Tau-Lepton Physics, Tau0

Measurement of \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-) and \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)

The products of the electron width of the J/\psi meson and the branching fraction of its decays to the lepton pairs were measured using data from the KEDR experiment at the VEPP-4M electron-positron collider. The results are \Gamma_{ee}(J/\psi)*Br(J/\psi->e^+e^-)=(0.3323\pm0.0064\pm0.0048) keV, \Gamma_{ee}(J/\psi)*Br(J/\psi->\mu^+\mu^-)=(0.3318\pm0.0052\pm0.0063) keV. Their combinations \Gamma_{ee}\times(\Gamma_{ee}+\Gamma_{\mu\mu})/\Gamma=(0.6641\pm0.0082\pm0.0100) keV, \Gamma_{ee}/\Gamma_{\mu\mu}=1.002\pm0.021\pm0.013 can be used to improve theaccuracy of the leptonic and full widths and test leptonic universality. Assuming e\mu universality and using the world average value of the lepton branching fraction, we also determine the leptonic \Gamma_{ll}=5.59\pm0.12 keV and total \Gamma=94.1\pm2.7 keV widths of the J/\psi meson.Comment: 7 pages, 6 figure

Search for narrow resonances in e+ e- annihilation between 1.85 and 3.1 GeV with the KEDR Detector

We report results of a search for narrow resonances in e+ e- annihilation at center-of-mass energies between 1.85 and 3.1 GeV performed with the KEDR detector at the VEPP-4M e+ e- collider. The upper limit on the leptonic width of a narrow resonance Gamma(R -> ee) Br(R -> hadr) < 120 eV has been obtained (at 90 % C.L.)

Measurement of main parameters of the \psi(2S) resonance

A high-precision determination of the main parameters of the \psi(2S) resonance has been performed with the KEDR detector at the VEPP-4M e^{+}e^{-} collider in three scans of the \psi(2S) -- \psi(3770) energy range. Fitting the energy dependence of the multihadron cross section in the vicinity of the \psi(2S) we obtained the mass value M = 3686.114 +- 0.007 +- 0.011 ^{+0.002}_{-0.012} MeV and the product of the electron partial width by the branching fraction into hadrons \Gamma_{ee}*B_{h} = 2.233 +- 0.015 +- 0.037 +- 0.020 keV. The third error quoted is an estimate of the model dependence of the result due to assumptions on the interference effects in the cross section of the single-photon e^{+}e^{-} annihilation to hadrons explicitly considered in this work. Implicitly, the same assumptions were employed to obtain the charmonium leptonic width and the absolute branching fractions in many experiments. Using the result presented and the world average values of the electron and hadron branching fractions, one obtains the electron partial width and the total width of the \psi(2S): \Gamma_{ee} =2.282 +- 0.015 +- 0.038 +- 0.021 keV, \Gamma = 296 +- 2 +- 8 +- 3 keV. These results are consistent with and more than two times more precise than any of the previous experiments

On feasibility of optimizing the neutronic parameters of a laser system pumped by a pulsed reactor

The paper examines the calculated feasibility of improving the energy characteristics of power pulses in a system consisting of a reactor and a subcritical block. A BARS-type fast neutron reactor is used as a self-quenching pulsed reactor. The subcritical block is a cylindrical structure comprising laser-active elements, moderator components and two reflectors (internal and external). The internal reflector material is zirconium hydride, and the external reflector material is beryllium. The pumping area containing the laser-active elements consists of zirconium hydride moderator, aluminum and uranium–molybdenum fuel (95% enriched uranium). The system operates in a pulsed mode. Fast neutrons are generated in the nuclear reactor at the pulse moment, many of which are leakage neutrons entering the subcritical block, slowing down there and inducing fissions of uranium nuclei in the laser-active elements. After the pulse terminates, the reactor changes to a deeply subcritical state, and the laser pulse generation stops. The neutron kinetics in the system under consideration is modeled based on a modified integral model. The pulse maximum power and energy in the system's subcritical block, as well as its weight and energy-to-weight ratio are selected as functionals for the optimization. The fissile material and moderator weight and the thickness of the subcritical block's internal and external reflectors are adopted as variables. The calculations have shown that it is possible to improve the energy characteristics of a reactor-laser system by increasing the amount of the fissile material in the block, not using the moderator in the block and fixing the thickness of the internal zirconium hydride reflector at a level of 3.1cm. It has been shown that a change in the external beryllium reflector thickness leads to a highly multidirectional behavior of the functionals (energy and maximum power, as well as the block weight and energy-to-weight ratio)