Thirty-year effects of liming on soil and foliage chemistry and growth of northern hardwoods in Pennsylvania, USA

The longevity of a single 22.4 Mg ha^-1 application of dolomitic limestone at four northern hardwood stands was evaluated over thirty years (1986-2016) to determine whether changes in soils, foliage, and tree growth were sustained on the unglaciated Allegheny Plateau in northern Pennsylvania, USA. In limed plots, soils, sampled to 45-55 cm depth, and sugar maple (<i>Acer saccharum</i> Marsh.) and black cherry (<i>Prunus serotina</i> Ehrh.) foliage had significantly ( P ≤ 0.05) greater concentrations of calcium (Ca) and magnesium (Mg) through 2016 compared with samples from unlimed plots. Calcium and Mg capitals (g m^-2) in the Oi through A horizon combined were greater on limed plots than unlimed plots, largely due to increases in the thickness and nutrient concentration in the A horizon. Over 30-years, sugar maple basal area increment (cm² yr^-1 BAINC) ) was greater in limed plots, American beech (<i>Fagus grandifolia</i> Ehrh.) BAINC was unaffected, and black cherry BAINC was reduced in limed plots compared with unlimed plots. The sustained effect of this one-time lime treatment shows the strong role of efficient nutrient cycling in forests and suggests that the benefits over a substantial portion of a stand rotation may increase the feasibility of operational liming.

Fatty Acid Composition, Antioxidant, and in vitro Anti-inflammatory Activity of Five Cold-Pressed Prunus Seed Oils, and Their Anti-biofilm Effect Against Pathogenic Bacteria

Background/Aim: Sweet almond (Prunus amygdalus dulcis) oil is one of the most famous cold-pressed seed oils. However, other species of Prunus can provide oils with healthy properties. We analyzed the fatty acid (FA) composition, as well as the antioxidant, the in vitro anti-inflammatory properties, and the antibiofilm activity of five commercial vegetable cold-pressed seed oils of apricot, peach, plum, cherry, and black cherry.Methods: Gas Chromatography-Mass Spectrometry was performed for the analysis of FAs The antioxidant property of the oils was carried using different tests [2, 2-diphenyl-1-picrylhydrazyl (DPPH assay)], Ferric Reducing Antioxidant Power (FRAP), and the 2, 20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+). The denaturation assay performed on bovine serum albumin (BSA) was used to evaluate the in vitro anti-inflammatory activity. The anti-biofilm activity was assessed using five pathogenic strains, namely, Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, through the crystal violet test and the 3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide (MTT), used to evaluate the metabolism of the microbial cells present within the biofilm.Results: Oleic acid and linoleic acids were the most abundant FAs. Black cherry seed oil exhibited the best antioxidant activity, but in general, the amount of oil needed to inhibit the activity of 1 ml of DPPH assay at 50% did not exceed 10 μg. The extract concentration for the 50% inhibition of the denaturation of the protein (IC50) did not exceed 4.4 μg. Linoleic and stearic acids affected the antioxidant activity of the oils; oleic acid, linolenic, and palmitoleic acids exhibited beneficial effects in preserving the BSA denaturation, as shown by the correlation data. The oils were able to inhibit the biofilm formation of the pathogens (up to 71.40% of inhibition) as well as act against their mature biofilm, although with different strengths, with values up to 61.54%. Concurrently, they also acted on the pathogen metabolism.Conclusion: The oils represent a valuable source of some healthy FAs. They showed potential antioxidant and anti-inflammatory in vitro activity, in addition, their potential effect on the biofilm can offer important ideas for research and reflection on their use as functional foods and/or ingredients.

Characterization of the Insect Assemblage and Associated Floral Volatiles of Black Cherry (Prunus serotina)

Black cherry is an ecologically important high-value wood. A decline of its regeneration has been reported in the USA, which could be associated with a lack of pollination. This study was conducted to identify insects visiting black cherry flowers, to determine whether insects captured on the flowers carry black cherry pollen and to identify the volatile organic compounds (VOCs) emitted by flowers of black cherry. A two-year insect survey was conducted before, during and after the black cherry bloom. A total of 9533 insects were captured in traps and Diptera was the most abundant (64.1%). Significantly more insects in Diptera, Lepidoptera and Thysanoptera were captured in the traps installed in the canopy than those on the ground, and Anthalia bulbosa (Diptera: Hybotidae) was the dominant species. Electron microscopy analyses demonstrated that insects captured in the canopy indeed carried black cherry pollen. Black cherry flowers emitted a VOC blend that is composed of 34 compounds and dominated by β-ocimene and several phenylpropanoids/benzenoids. This floral VOC profile is similar to that of other pollinator-dependent Prunus species. This study reports pollinator insects and associated VOCs, for the first time, that could play a significant role in the pollination and regeneration of black cherry.

Physicochemical Characteristics and Bioactive Compounds of New Black Cherry Tomato (Solanum lycopersicum) Varieties Grown in Vietnam

Some physicochemical characteristics and bioactive compounds of three varieties of black cherry tomato (Indigo Rose, OG, F1:001) grown in Vietnam were investigated. The results showed that the two varieties OG and F1:001 have roughly the same size with weight, height, diameter, geometric diameter and surface area ranging from 21.62 to 22.25 g, 25.69 to 26.40 mm, 24.46 to 25.11 mm, 24.86 to 25.53 mm and 19.47 to 20.51 cm2, respectively. Meanwhile, the Indigo variety is twice as large with the corresponding parameters as 45.2 g, 48.03 mm, 55.18 mm, 52.69 mm and 87.20 cm2. All three varieties are in a spherical shape with sphericity and aspect ratios ranging from 96.72 to 109.69% and 0.951 to 1.149, respectively. The variety of OG contained higher levels of bioactive compounds, especially anthocyanin, not only in the skin but also in the outer tissue. Six anthocyanin compounds were identified in the two varieties of OG and Indigo Rose while only four anthocyanin compounds were found in the variety of F1:001. Among them, two new compounds (delphinidin-3-(p-coumaroyl)-glucoside and delphinidin-3-(p-coumaroyl)-glucoside-arabinoside) were discovered in all three varieties. The finding of this study will be a basis for consumers to better understand the nutritious properties of black cherry tomatoes grown in Vietnam, thereby promoting the need to grow and consume this beneficial fruit. The study also provides the important physicochemical parameters of black cherry tomatoes, which are the initial basis for fruit preservation and processing.

Phenolic composition of leaf and flower extracts of black cherry (Prunus serotina Ehrh.)

Key Message The best yields in the extraction of hydroxycinnamic acids, flavanols and total phenolics from black cherry flowers were obtained with 40% ethanol and the poorest with water. A 30% higher content of total phenolics was obtained from leaves by using methanol rather than water. Context Black cherry (Prunus serotina Erhr.) is widespread in Europe. Because it is an invasive species, most research has been aimed at trying to find a method to remove this shrub from forests. The incentive for the development of the research was that we were trying to find a possible folk use of black cherry leaves and flowers. Aims The aim of this work was to study the detailed phenolic profile of extracts of P. serotina leaves and flowers. Methods Three types of extracts of P. serotina were made. The extracts were analysed for differences in phenolics content based on different extraction methods. HPLC-MSn was used to identify the phenolic compounds, and HPLC–DAD was used for their quantification. Results The results show that different extraction methods result in differences in the amount of extractables. Flavanols are the main group of identified compounds in both leaves and flowers. A larger extraction efficiency leads to a higher amount of phenolics in the flowers compared to leaves (49.8 vs. 36.5 g/kg dry weight). No difference was detected in the amount of phenolics between water extracts of leaves and flowers. Each extract can be considered rich in phenolics. Conclusion This work shows that leaves and flowers of P. serotina are a rich source of phenolic compounds. We provide interesting results that might be of interest in the industrial valuation of several compounds.

Viral reservoir capacity of wild Prunus alternative hosts of plum pox virus through multiple cycles of transmission and dormancy

Plum pox virus (PPV) is a significant pathogen of Prunus worldwide and is known for having a broad experimental host range. Many of these hosts represent epidemiological risks as potential wild viral reservoirs. A comparative study of the PPV reservoir capacity of three commonly found native North American species, western choke cherry (P. virginiana var. demissa), black cherry (P. serotina), and American plum (P. americana) was conducted. Pennsylvania isolates of PPV-D were transmitted from the original host peach (P. persica cv. GF305) to all three species. Viral accumulation and transmission rates to alternative hosts and peach were monitored over the course of five vegetative growth and cold induced dormancy (CID) cycles. The three alternative host species demonstrated differences in their ability to maintain PPV-D and the likelihood of transmission to additional alternative hosts or back transmission to peach. Western choke cherry had low (5.8%) initial infection levels, PPV-D was not transmissible to additional western choke cherry, and transmission of PPV-D from western choke cherry to peach was only possible before the first CID cycle. Black cherry had intermediate initial infection levels (26.6%) but did not maintain high infection levels after repeated CID cycles. Conversely, American plum had a high level (50%) of initial infection that was not significantly different from initial infection in peach (72.2%) and maintained moderate levels (15-25%) of infection and PPV-D transmission to both American plum and peach through all five cycles of CID. Our results indicate that American plum has the greatest potential to act as a reservoir host for Pennsylvania isolates of PPV-D.

Effect of Prunus serotina Ehrh. Volatile Compounds on Germination and Seedling Growth of Pinus sylvestris L.

In temperate European forests invaded by Prunus serotina Ehrh. (black cherry), a reduction in the spontaneous regeneration capacity of Pinus sylvestris L. (Scots pine) is observed. It could be caused by various factors, including allelopathic properties of this invasive plant. In this study the phytotoxic effect of P. serotina volatile compounds on P. sylvestris and the seasonal variation in this effect were assessed. Simple assays showed that volatiles emitted from P. serotina leaves significantly inhibited root growth of P. sylvestris seedlings. Their negative effect on stem growth was much weaker. The strongest phytotoxic effect on Scots pine seedlings was caused by the volatiles emitted from the youngest black cherry leaves. In fresh foliage of P. serotina, nineteen volatile organic compounds were identified by gas chromatography–mass spectrometry (GC–MS). The dominant compound was benzaldehyde. On the basis of tests of linalool alone, it was found that this monoterpene present in the volatile fraction has a strong allelopathic potential and inhibits germination, root elongation and shoot elongation of pine seedlings. The results of our research suggest that volatile compounds from P. serotina leaves could limited survival of P. sylvestris individuals in the seedling phase.

Composition of Phenolic Compounds, Cyanogenic Glycosides, Organic Acids and Sugars in Fruits of Black Cherry (Prunus serotina Ehrh.)

The forest understory is rich in fruit-bearing trees and shrubs. They include both native species and invasive alien plant species (IAPS). One of the most spreading IAPS is black cherry (Prunus serotina E.). Problems with the invasiveness of P. serotina is well known in many European countries. However, there are very few studies related to this IAPS. This article aims to fill the gap in research on the bioactive compounds of black cherry fruits and thus to start a discussion on the potential use of this species on an industrial or semi-industrial scale, which may lead to the reduction of this species presence in forests. Fruits were collected in a forest of Northern Poland. Contents of sugars, phenolic compounds as well as cyanogenic glycosides were determined. Pphenolic compounds and cyanogenic glycoside were assayed using HPLC-DAD coupled with MSn. Sugars and organic acids were determined with the use of HPLC-DAD. Fruits of P. serotina can be considered as rich in anthocyanins, even at a lower level of total phenolics than in their plantation-grown couterparts, fruits of black cherry are still a good source of dietary phenolics of natural, forest-grown origin. When stones are not crushed during processing the level of GCC is within a safe, admissible range.