Katarzyna Rubinowska

Various metabolic modulators have been widely used in recent years to increase the accumulation of desired secondary metabolites in medicinal plants, although most studies to date have focused on in vitro systems. Although simpler and cheaper, their potential application in vivo is still limited. Therefore, the aim of this study was to compare the effect of three chemically different elicitors (150 mg/L chitosan lactate—ChL; 10 mg/L selenium as selenite—Se; 100 mg/L salicylic acid—SA) applied to the soil substrate on some aspects of the secondary metabolism and physiological responses of Chelidonium majus L. Using HPLC-DAD, six isoquinoline alkaloids were identified and quantified in shoot extracts. LC-ESI-TOF-MS analysis confirmed the molecular identity of all target alkaloids, supporting the identification. The strongest stimulatory effect on the accumulation of protopine, berberine, and allocryptopine was observed with the Se and SA treatment, whereas ChL was less effective. In turn, the dominant alkaloids (coptisine and chelidonine) remained unaffected. There was also an increase in total phenolic compounds, but not in soluble flavonols. The elicitor treatments caused an increase in the antioxidant activity of the plant extracts obtained. Regardless of the metabolic modulator type, the strongest effect was generally observed on days 7 and 10 after application. No visual signs of toxicity and no effect on shoot biomass were found, although some elicitor-induced changes in the oxidative status (increased H₂O₂ accumulation and enhanced lipid peroxidation) and free proline levels in leaves were observed. We suggest that Se or SA can be applied to C. majus grown in a controlled pot culture to obtain high-quality raw material and extracts with increased contents of valuable specialized metabolites and enhanced antioxidant capacity.

In recent years, there has been growing interest in the use of native ground-grown perennials in floral compositions as cut greenery. The easily available plant materials that can replace some exotic species include Hosta leaves and the leafy shoots of Polygonatum multiflorum. Their vase life should be at least as long as that of the flowers, with which they are combined. In order to prolong the vase life of cut greenery, the conditioning of cut plant material in solutions of plant hormones (GA3 and BA) and commercial conditioning substances (8HQC and Chrysal Clear 2) is most commonly performed. The aim of this study was to evaluate the effect of different conditioning solutions on vase life and parameters indicating the progression of the senescence of plant materials. Cut Hosta leaves and leafy shoots of Polygonatum multiflorum were conditioned immediately after cutting for 24 h in aqueous solutions of benzyladenine (BA) and gibberellic acid (GA₃), 8HQC standard medium with the addition of 2% sucrose and 1% Chrysal Clear 2 solution. The post-harvest storage and physiological senescence parameters of the plant materials were analyzed using the following indicators: the vase life, the relative water content (RWC), electrolyte leakage (E_L), and thiobarbituric acid reactive substance (TBARS) and pigment contents (chlorophyll a, chlorophyll b, carotenoids, and anthocyanins). Conditioning Hosta leaves in a BA solution at 100 mg L⁻¹ immediately after cutting more than doubles their post-harvest vase life. The longevity of P. multiflorum shoots can be effectively extended by storage in a BA solution of 400 mg L⁻¹, for 24 h. Both the plant materials responded to the progressive aging process with the disruption of water management, a reduction in cytoplasmic membrane integrity, and a decrease in the plant pigment content. Tissue water retention in the Hosta leaves was most favorably affected by conditioning in the GA₃ solution at a concentration of 400 mg L⁻¹. The P. multiflorum shoots responded with tissue water retention to conditioning in 1% Chrysal Clear 2 solution. The conditioning of Hosta leaves in BA solution at 400 mg L⁻¹ stabilized the cytoplasmic membranes and inhibited E_L most effectively. In P. multiflorum, the lowest E_L level was found as an effect of conditioning the shoots in GA₃ solution at 200 mg L⁻¹. The degradation of assimilation pigments was prevented by conditioning the Hosta leaves in GA₃ solution at 200 mg L⁻¹ and the P. multiflorum leafy shoots in GA₃ solution, regardless of the concentration used. Although the prolongation of the vase life of the cut leaves and the shoots by up to 30 days was achieved, along with an improvement in the appearance of the plant materials, it was not possible to identify a single conditioner that had a positive effect on all the parameters studied.

Strelitzia reginae is an important cut flower native to South Africa. The effect of silicon and gibberellic acidwith sucrose as conditioners on the post-harvest quality of Strelitzia cut flowers was investigated. Inflorescence shoots were conditioned for 24 hours in: water solutions of Actisil 0.2% or gibberellic acid (GA3) – 200 mg∙dm–3 + sucrose 10% or distilled water (control). The shoots were then placed in distilled water or Chrysal Clear Professional 2 (10%). It was found that GA3 + sucrose and Actisil increased the size of orange sepals and blue petals when after conditioning, the shoots were placed in water or Chrysal. Conditioning in Actisil and storage in Chrysal increased the value of mechanical parameters of flowers, leading to greater flexibility and lower susceptibility to fracture. Conditioning the shoots in Actisil and keeping them in Chrysal extended the life of flowers by 2 days.

Three aphid species, Eriosoma ulmi (L.), Colopha compressa (Koch) and Tetraneura ulmi (L.) induce distinct gall morphotypes on Ulmus glabra Huds.; opened and closed galls. Because the trophic relationship of aphids and their galls shows that throughout the gall formation aphids can elicit multiple physiological regulations, we evaluated the changes of hydrogen peroxide content (H₂O₂), cytoplasmic membrane condition, expressed as electrolyte leakage (E_L) and concentration of thiobarbituric acid reactive substances (TBARS), as well as, the activity of catalase (CAT), guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) in gall tissues, as well as, in damaged and undamaged parts of galled leaves. All aphid species increased E_L from gall tissues and significantly upregulated APX activity in galls and galled leaves. Alterations in H₂O₂ and TBARS concentrations, as well as GPX and CAT activities, were aphid- and tissue-dependent. The development of pseudo- and closed galls on elm leaves did not have a clear effect on the direction and intensity of the host plant’s physiological response. The different modes of changes in H₂O₂, TBARS, CAT and GPX were found in true galls of C. compressa and T. ulmi. Generally, physiological alterations in new plant tissues were quite different compared to other tissues and could be considered beneficial to galling aphids.

To obtain healthy and good quality plants from in vitro cultivation, it is necessary to produce plantlets with well-developed rooting systems because they must undergo acclimatization, a final and a very difficult stage of micropropagation. In the present research, the effect of auxins NAA, IAA and IBA in concentrations of 0.5; 1; 2.5 and 5 mg·dm⁻³ on the Paphiopediluminsigne in vitro rooting was studied, and it was noted that 1 mg·dm⁻³ of IAA or IBA enabled the obtaining of a lot of rooted and good quality plantlets. The subsequent influence of the two most advantageous auxins on the acclimatization of plantlets in different substrates (sphagnum moss, sphagnum moss + substrate for orchids, substrate for orchids, substrate for orchids + acid peat) was tested, in the means of morphological features of plants and their physiological parameters, i.e., chlorophyll fluorescence (FV, Fm, Fv/Fm), stress enzyme activity (catalase, ascorbate peroxidase), and water balance. Considering all the tested features, it might be stated that the best results were obtained when explants were rooted in vitro in the presence of 1 mg·dm⁻³ of IAA and then planted ex vitro in substrate for orchids.

Due to the dynamic development of the floriculture market, new species and varieties of plants that can potentially be used as a source of cut greenery are constantly being sought. The experiment was conducted to analyze the effect of the cultivation site (unheated foil tunnel and open field) and treatments with the Pentakeep V formulation (0.00%, 0.02%, 0.04%, and 0.06%) on the vase life and postharvest quality of Polygonatum multiflorum ‘Variegatum’ cut foliage. There was a positive effect of the cultivation in the unheated foil tunnel on the vase life and biochemical parameters, namely the electrolyte leakage (E_L), thiobarbituric acid reactive substances (TBARS), chlorophyll a + b (Chl. a + b), proline, peroxidase (POD), and ascorbate peroxidase (APX), of P. multiflorum cut foliage. Foliar application of Pentakeep V formulation at concentrations of 0.04% and 0.06% contributed to a decrease in the TBARS content in the P. multiflorum cut leaves, regardless of the plant cultivation site. Additionally, it reduced proline production in cut leaves of P. multiflorum cultivated in the unheated foil tunnel, which was confirmed by the analyses carried out after the 30 days of the experiment. Furthermore, the exogenous application of ALA during P. multiflorum cultivation inhibited POD activity, irrespective of its concentration and the site of plant cultivation.

Thalictrum aquilegifolium L. ‘Black Stockings,’ with its interesting foliage, is used as a cut greenery. We tested the postharvest longevity of the foliage after different 24-hr conditioning treatments with nanosilver (0, 5, 10, 15, 20 mg dm−3) and 20 g dm−3 sucrose and compared the results with those obtained using the standard preservative (200 mg dm−3 8-hydroxyquinoline citrate + 20 g dm−3 sucrose) and Floralife 200 Clear. The longevity of the foliage and the content of assimilative pigments were evaluated and the functioning of the photosynthetic apparatus (F0, Fm, Fv/Fm) was analyzed. We found that leaf senescence, as determined by chlorophyll a and carotenoid content after 14 days of holding, was most effectively inhibited by the solution containing 5 mg dm−3 nanosilver and sucrose. This solution increased the maximal quantum efficiency of photosystem II (Fv/Fm) in the leaves.

ISHS XXX International Horticultural Congress IHC2018: II International Symposium on Micropropagation and In Vitro Techniques Growth and development of Hakonechloa macra in tissue culture depending on the type and color of light

Gall formation is associated with multiple changes in plant cells, which still requires a better understanding. In this study, galls caused by sexual generation (♀♂) ofNeuroterus quercusbaccarum(L.) (Hymenoptera: Cynipidae) on pedunculate oak trees (Quercus roburL.) were used as a model. Cytoplasmic membrane condition, concentration of hydrogen peroxide (H₂O₂), the activity of antioxidant enzymes and amino acid decarboxylase as well as chlorophyll fluorescence parameters were determined. Changes in physiological and biochemical parameters were analyzed in foliar tissues with galls and gall tissues themselves and compared to control. The presence of galls on oak leaves caused an increase of lipid peroxidation level. A significant decline in H₂O₂and TBARS content with the reduction of guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) activity were observed in gall tissues. The activity amino acid decarboxylase, i.e., LDC, ODC and TyDC varied between samples, which may affect the content of amino acids. The presence ofN. quercusbaccarumgalls caused an insignificant increase of the chlorophylls, carotenoids and anthocyanin contents, while the content of pigments and their ratios in gall tissues was extremely low. Moreover, photosynthetic parameters (F₀,F_m,F_v/F_m,Y,q_P) were significantly decreased. Data generated in this study indicate that the development ofN. quercusbaccarumgalls on pedunculate oak leaves has a negative effect on host plant related to the disruption of cell membrane integrity, disturbance of photosynthesis and reduction of the antioxidant potential of the host plant.