Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. The understanding of its chemical and physical properties, which are strongly related to the type of the ...initial material used and pyrolysis conditions, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes with different characteristics (e.g., rice husk (RH), rice straw (RS), wood chips of apple tree (Malus pumila) (AB), and oak tree (Quercus serrata) (OB)) were pyrolyzed at different temperatures (400, 500, 600, 700, and 800 °C) in order to optimize the physicochemical properties of biochar as a soil amendment. Low-temperature pyrolysis produced high biochar yields; in contrast, high-temperature pyrolysis led to biochars with a high C content, large surface area, and high adsorption characteristics. Biochar obtained at 600 °C leads to a high recalcitrant character, whereas that obtained at 400 °C retains volatile and easily labile compounds. The biochar obtained from rice materials (RH and RS) showed a high yield and unique chemical properties because of the incorporation of silica elements into its chemical structure. The biochar obtained from wood materials (AB and OB) showed high carbon content and a high absorption character.
•Five polyphenols from apple leaf were successfully isolated by HSCCC-prep-HPLC.•Optimization of HSCCC conditions was realized by response surface methodology.•The experimental value was in good ...consistence with the predicted value.•Polyphenols except phloridzin showed significant neuronal protection effect.
Considering comprehensive utilization of natural products, isolation and activity determination processes of bioactive compounds are essential. In this study, a combined high-speed countercurrent chromatography (HSCCC) with preparative HPLC method was developed to isolate the five antioxidant polyphenols from 75% ethanol extract of Malus pumila Mill. leaves. The HSCCC conditions were optimized by response surface methodology (RSM) considering two response indexes including retention of stationary phase and analysis time. The optimal HSCCC conditions were flow rate of 2.11 mL/min, revolution speed of 717 rpm, and temperature of 25℃, with a solvent system of ethyl acetate/methanol/water (10:1:10, v/v/v). The unseparated fractions obtained from HSCCC were subjected to preparative HPLC for further isolation. As a result, phloridzin (15.3 mg), isoquercitrin (2.1 mg), quercetin 3-O-xyloside (1.9 mg), quercetin-3-O-arabinoside (4.0 mg), and quercitrin (2.0 mg) were isolated from 200.0 mg extracts. The purities of these compounds were all above 92%. Their chemical structures were identified by mass spectrometer and nuclear magnetic resonance. The five isolated compounds were further investigated for their rat hippocampal neuroprotective effects against hydrogen peroxide-induced oxidative stress. No cytotoxicity was observed in all tested concentrations. While all five compounds except phloridzin showed significantly neurogenic activities and neuroprotective effects, especially at the concentration of 0.5 mg/L. These results demonstrate that RSM is a suitable technique for optimisation of HSCCC and the isolated polyphenols can be used as antioxidants in pharmaceutical and food products.
Herein, we explored the potential of the apple's core microbiota for biological control of Erwinia amylovora, which causes fire blight disease, and analyzed the structure of the apple's bacterial ...community across different tissues and seasons. Network analysis results showed distinct differences in bacterial community composition between the endosphere and rhizosphere of healthy apples, and eight taxa were identified as negatively correlated with E. amylovora, indicating their potential key role in a new control strategy against the pathogen. This study highlights the critical role of the apple's bacterial community in disease control and provides a new direction for future research in apple production. In addition, the findings suggest that using the composition of the apple's core taxa as a biological control strategy could be an effective alternative to traditional chemical control methods, which have been proven futile and environmentally harmful.
Irradiation with γ-rays, electron beams, and X-rays was a widely accepted plant quarantine treatment, and the International Standards for Phytosanitary Measures (ISPM) have been gradually prepared ...against regulated pests. The effective doses against these pests for phytosanitary irradiation were recently admitted as new annexes in ISPM No. 28. In Japanese fruits, the peach fruit moth and Japanese orange fly commonly become the causes of severe issues in exporting apples and Satsuma mandarins from Japan. Therefore, the species-specific dose for peach fruit moth and the generic dose for the family Tephritidae were administered to confirm the effectiveness of irradiation treatments to prevent the adult emergence of these pests. Moreover, depending on the dose level, the fruit quality might be affected by irradiation, although different fruit cultivars might show different responses. The responses of apple and Satsuma mandarin cultivars in Japan should be clarified to determine applicability of irradiation treatments. Preliminary assessment on Japanese cultivars of 11 kinds of apples and 3 mandarins were investigated in this report. In conclusion, phytosanitary irradiations are effective against two pests in apples or Satsuma mandarins while keeping high quality as the commodity.
•Phytosanitary exposure was effective on preventing adult emergence of fruit pests.•Preliminary assessment was investigated on the fruit quality after irradiation.•Practical quarantine irradiation was successfully achieved without quality changes.•Severe physiological changes were not observed on apple cultivars using 525 Gy.•Almost no changes were observed in mandarin cultivars after the 350-Gy exposure.
•Although much research has been conducted on regulated deficit irrigation, there is little research on the regulated deficit irrigation of apple trees under the special irrigation method of ...surge-root irrigation in the Loess Plateau of China.•The water consumption of apple trees is higher than that of ordinary crops, and the water demand during the different growth periods is inflexible.•The main irrigation method employed in this region is flood irrigation, and the water use efficiency is low.•An appropriate irrigation system is urgently required to improve the water use efficiency of apple trees in this region.•This study investigated the response of the fruit quality, fruit yield, and water use efficiency to regulated deficit irrigation during the different growth stages of apple trees (Malus pumila Mill) in the Loess Plateau of northern China, to determine the optimal water deficit period of apple trees to provide a scientific basis for water management and the precise irrigation of apple trees.
This study investigated the response of the fruit quality, fruit yield, and water use efficiency (WUE) to regulated deficit irrigation (RDI) during the different growth stages of apple trees (Malus pumila Mill) in the Loess Plateau of northern China. Different water deficit treatments were applied in 2016 and 2017 on a field planted with 5-year-old apple trees. The treatments included low (L), moderate (M), and severe (S) water deficit treatments during the bud burst to leafing (I), flowering to fruit set (II), and fruit growth (III) stages. Compared with full irrigation (FI), water deficit treatment during the different growth stages had significant effects on the fruit quality, fruit yield, and WUE of the apple trees. The L and M water deficit treatments during stage III significantly reduced the apple yield by 10.89% and 13.46% in 2016 and 3.66% and 10.10% in 2017, respectively. A water deficit during stage III decreased the single fruit weight, excellent-fruit percentage, and fruit water content by 2.79%–11.31%, 15.24%–20.36%, and 4.26%–10.07%, respectively, and increased fruit firmness, soluble solid content, and soluble reducing sugar content by 12.70%–21.31%, 13.83%–33.60%, and 10.13%–21.48%, respectively. The L and M water deficit treatments applied during stage I resulted in apple quality and yield that were similar to those resulting from the FI treatment, but the WUE was significantly higher in the L and M water deficit treatments than in the FI treatment. The optimal period for water deficit treatment is stage II, during which the highest yield and WUE were found. The L and M treatments during stage II increased the fruit yield by 13.93% and 13.28% in 2016 and 17.94% and 17.13% in 2017, respectively. The WUE of the apple trees was higher with the I I-L and I I-M treatments (greater than 7 kg m−3) than with other treatments. In addition, water deficit treatment during stage II caused a slight increase in fruit firmness and a slight decrease in fruit water content, which produces apples suitable for storage. Single fruit weight, excellent-fruit percentage, and soluble solid and soluble reducing sugar content were significantly improved, making the apples sweeter; thus, a water deficit during stage II had a significant positive effect on apple quality, with the I I-M treatment being optimal and the II-L treatment being second best. The optimal water deficit treatment of the II-M treatment enhances the fruit quality, yield, and WUE of apple trees in water-scarce environments.
Abstract
Background and Aims
The programmed softening occurring during fruit development requires scission of cell wall polysaccharides, especially pectin. Proposed mechanisms include the action of ...wall enzymes or hydroxyl radicals. Enzyme activities found in fruit extracts include pectate lyase (PL) and endo-polygalacturonase (EPG), which, in vitro, cleave de-esterified homogalacturonan in mid-chain by β-elimination and hydrolysis, respectively. However, the important biological question of whether PL exhibits action in vivo had not been tested.
Methods
We developed a method for specifically and sensitively detecting in-vivo PL products, based on Driselase digestion of cell wall polysaccharides and detection of the characteristic unsaturated product of PL action.
Key Results
In model in-vitro experiments, pectic homogalacturonan that had been partially cleaved by commercial PL was digested to completion with Driselase, releasing an unsaturated disaccharide (‘ΔUA–GalA’), taken as diagnostic of PL action. ΔUA–GalA was separated from saturated oligogalacturonides (EPG products) by electrophoresis, then subjected to thin-layer chromatography (TLC), resolving ΔUA–GalA from higher homologues. The ΔUA–GalA was confirmed as 4-deoxy-β-l-threo-hex-4-enopyranuronosyl-(1→4)-d-galacturonic acid by NMR spectroscopy. Driselase digestion of cell walls from ripe fruits of date (Phoenix dactylifera), pear (Pyrus communis), rowan (Sorbus aucuparia) and apple (Malus pumila) yielded ΔUA–GalA, demonstrating that PL had been acting in vivo in these fruits prior to harvest. Date-derived ΔUA–GalA was verified by negative-mode mass spectrometry, including collision-induced dissociation (CID) fragmentation. The ΔUA–GalA:GalA ratio from ripe dates was roughly 1:20 (mol mol–1), indicating that approx. 5 % of the bonds in endogenous homogalacturonan had been cleaved by in-vivo PL action.
Conclusions
The results provide the first demonstration that PL, previously known from studies of fruit gene expression, proteomic studies and in-vitro enzyme activity, exhibits enzyme action in the walls of soft fruits and may thus be proposed to contribute to fruit softening.
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