Cell membrane permeability and antioxidant activities in the rootstocks of Miscanthus x giganteus as an effect of cold and frost treatment

The aim of the study was to estimate the ability of Miscanthus x giganteus to acquire frost tolerance. Field grown rootstocks were transferred into pots and cultivated in a glasshouse at 20°C. After 5 weeks plants were pre-hardened at 12°C for a further 2 weeks and then hardened at 5°C for another 3 weeks. After this time, plants were frozen at -8°C or -15°C for 1, 3 or 5 days, after which their regrowth at 20°C was investigated. The membrane permeability (electrolyte leakage), activity of the catalase (CAT), non-specific peroxidase (PX), and protein content in stolons were measured, before and after pre-hardening, as well as after hardening and freezing. Both pre-hardening and hardening decreased membrane permeability of the rootstock cells, and this effect was observed further, after 5-week of regrowth at 20°C. Freezing at both temperatures increased ion leakage gradually over the period of treatment. On the basis of total ion content, damage to the cell membranes of frozen stolons after recovery was state. Prehardening increased CAT activity, while hardening did not alter it. However, after 5-week de-hardening, CAT activity decreased significantly. Freezing at -8°C for 5 days increased significantly the activity of this enzyme. At -15°C CAT activity was lower than in the control after only one day of freezing. PX activity decreased both in the rootstocks of cold (12°C and 5°C) and frost treated plants. Protein content increased significantly in the stolons of both pre-hardened and hardened plants, although not immediately after cold treatment, but only after a 5-week re-growth period in a glasshouse at 20°C. This phenomenon was observed also in the stolons of plants frozen at -15°C for 5 days. From frozen rootstocks no new stems in regrowth conditions were obtained. The results obtained indicated, that although frozen stolons cannot produce new shoots, they do demonstrate some metabolic vitality. So, it could be supposed that the frost susceptibility of studied plants resulted from the strong sensitivity of shoot apical meristems to the cold. Further studies will analyse the survival of Miscanthus in milder frost temperatures

Impact of cold-induced antioxidant activity on frost resistance in androgenic Festulolium genotypes

The aim of the study was: (i) to state if selected in the field conditions androgenic Festulolium genotypes are diverse in frost tolerance, and (ii) to investigate if changes in anitoxidant activity could be recognized as a physiological marker of this type tolerance. Antioxidative system induced by prehardening (12°C) and hardening (2°C) temperatures was investigated in 6 androgenic genotypes generated from a Festuca pratensis × Lolium multiflorum (2n = 4x = 28) amphidiploid hybrid (four genotypes derived from the F1 hybrids, and two genotypes derived from the Festulolium cultivar ‘Rakopan’). The electrolyte leakage, frost resistance expressed as the values of temperature causes 50% damages (LT50), the activities of superoxide dismutase (SOD), catalase (CAT), non-specific peroxidase (PX) and ascorbate peroxidase (APX) were measured. The results obtained indicated weak diversity of frost tolerance among studied androgenic genotypes. Only the one genotype was chosen as the most resistant to frost, while the other genotypes demonstrated no significant differences in values of LT50 coefficient recorded after hardening. Prehardening temperature of 12°C caused an increase in cell membrane permeability in all genotypes studied. After hardening ion leakage from cells declined up to the control level. Generally, cold activated SOD, PX and APX in leaves of the genotypes studied, and inhibited strongly CAT activity. The most frost tolerant genotype was characterized by high PX activity after hardening process.Abbreviations: APX – ascorbate peroxidase, CAT – catalase, EDTA – ethylenediaminetatraacetic acid, LT50 – letal temperature causing 50% membrane cell damages, NBT – nitroblue tetrazolium, PPFD – photosynthetic photon flux density [μmol m-2 s-1], PX – non-specific peroxidase, RH – relative humidity, ROS – reactive oxygen species, SE – standard error, SOD – superoxide dismutas

Feasibility studies of time-like proton electromagnetic form factors at PANDA at FAIR

Simulation results for future measurements of electromagnetic proton form factors at \PANDA (FAIR) within the PandaRoot software framework are reported. The statistical precision with which the proton form factors can be determined is estimated. The signal channel $\bar p p \to e^+ e^-$ is studied on the basis of two different but consistent procedures. The suppression of the main background channel, $\textit{i.e.}$ $\bar p p \to \pi^+ \pi^-$, is studied. Furthermore, the background versus signal efficiency, statistical and systematical uncertainties on the extracted proton form factors are evaluated using two different procedures. The results are consistent with those of a previous simulation study using an older, simplified framework. However, a slightly better precision is achieved in the PandaRoot study in a large range of momentum transfer, assuming the nominal beam conditions and detector performance

Study of doubly strange systems using stored antiprotons

Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the P‾ANDA experiment at FAIR. For the first time, high resolution γ-spectroscopy of doubly strange ΛΛ-hypernuclei will be performed, thus complementing measurements of ground state decays of ΛΛ-hypernuclei at J-PARC or possible decays of particle unstable hypernuclei in heavy ion reactions. High resolution spectroscopy of multistrange Ξ−-atoms will be feasible and even the production of Ω−-atoms will be within reach. The latter might open the door to the |S|=3 world in strangeness nuclear physics, by the study of the hadronic Ω−-nucleus interaction. For the first time it will be possible to study the behavior of Ξ‾+ in nuclear systems under well controlled conditions

Precision resonance energy scans with the PANDA experiment at FAIR: Sensitivity study for width and line shape measurements of the X(3872)

This paper summarises a comprehensive Monte Carlo simulation study for precision resonance energy scan measurements. Apart from the proof of principle for natural width and line shape measurements of very narrow resonances with PANDA, the achievable sensitivities are quantified for the concrete example of the charmonium-like X(3872) state discussed to be exotic, and for a larger parameter space of various assumed signal cross-sections, input widths and luminosity combinations. PANDA is the only experiment that will be able to perform precision resonance energy scans of such narrow states with quantum numbers of spin and parities that differ from J P C = 1 - -

Accumulation of H ₂ O ₂ and changes in activities of antioxidative enzymes and β -1,3-glucanase in barley and meadow fescue leaves attacked by Bipolaris sorokiniana

The effects of Bipolaris sorokiniana inoculation on accumulation of hydrogen peroxide and changes in the activities of superoxide dismutase (SOD), catalase (CAT), non-specific peroxidase (PX) and β -1,3-glucanase enzymes in leaves of differentially resistant spring barley and meadow fescue were investigated in this study. Hydrogen peroxide accumulated slightly in inoculated barley leaves 24 hours after inoculation, and its accumulation after 48 hours of pathogenesis remained week around sites of infection. In leaves of fescue, which is more resistant to B. sorokiniana , accumulation of H 2 O 2 was faster and stronger in comparison to barley. A slight increase in SOD activity was observed only in infected fescue. Catalase activity in infected barely leaves decreased significantly 48 hours after inoculation, while in fescue-infected plants CAT activity, following a slight decrease, remained similar to the control values. PX activity was considerable lower in inoculated barley leaves after 6 hours, but at 24 and 48 hours after inoculation its activity increased significantly compared to the control. In inoculated fescue leaves activity of PX was higher at 6 and 24 hours compared to the control, while at 48 hours PX activity was strongly inhibited. β -1,3-Glucanase activity in inoculated barley plants did not differ from that of the control, while in infected fescue leaves it increased significantly 48 hours after inoculation. Based on the results, we suggest that the strong accumulation of H 2 O 2 , changes in antioxidant levels, together with the significant increase of β -1,3-Glucanase activity in infected fescue leaves, plays an important role in fescue’s greater resistance to B. sorokiniana