Melatonin is a crucial regulator of fruit growth and development. However, the mechanisms by which pre-harvest application of melatonin regulates the metabolism of phenolic compounds in pear pericarp remain poorly understood. In this study, the effect of pre-harvest spraying of melatonin on the synthesis of phenolics in pear peel and the regulatory mechanism were investigated using a multi-disciplinary approach, integrating physiological and biochemical, transcriptomic, and metabolic analyses, and the “Yuluxiang” pear as the test material. The pre-harvest spraying of 100 μM melatonin notably increased the single fruit weight, total soluble solids (TSS) and total soluble solids/titratable acid (TSS/TA) ratio. In addition, the spraying regimen elevated the concentrations of phenolic substances, including anthocyanosides, chlorogenic acid, and lignin, in the fruit peel. Three comparison groups (T0 vs. CK0, T1 vs. CK1, and T2 vs. CK2) showed 354, 1385, and 816 differentially expressed genes (DEGs) and 240, 411, and 210 differentially expressed metabolites (DEMs), respectively. Transcriptome results from melatonin treatment significantly affected the key metabolic pathways, including signal transduction, hormone regulation, glucose metabolism, secondary metabolites biosynthesis, phenylpropanoid biosynthesis, and flavonoid biosynthesis. Melatonin treatment also influenced the expression of key genes in phenylpropanoid biosynthesis and flavonoid biosynthesis pathways, such as PAL, C4H, 4CL, CAD, CHS, UFGT, POD, and others. Metabolomic data suggested the melatonin treatment notably stimulated the biosynthesis of l-phenylalanine, cinnamic acid, caffeic acid, ferulic acid, leucocyanidin and uridine 5ʹ-diphospho-d-glucose than control. By examining the expression patterns of transcription factors, we identified 12 transcription factors (TFs), including PbrMYB4, PbrMYB36-like, PbrMYB14, PbrREF4 and PbrNAC6-like, as potential key TFs involved in melatonin-regulated polyphenol biosynthesis. The pre-harvest application of 100 μM melatonin can help improve the visual and flavor quality of pear fruits. It can influence the key enzyme genes’ expression of phenolic metabolism while stimulating the production of l-phenylalanine, cinnamic acid, caffeic acid, ferulic acid, leucocyanidin and uridine 5ʹ-diphospho-d-glucose, which promote the biosynthesis of anthocyanidins, phenolic acids, and lignins. These findings provide comprehensive insights into the metabolic mechanisms of melatonin-regulated phenolic compounds in pear peels.

Low-temperature stress is a limiting factor affecting the safe overwintering and stable production of apples. Galactinol, produced by galactinol synthase (GolS), is an important plant cryoprotectant. This study showed for the first time that exogenous spraying of apple saplings with 100 mg mL- 1 galactinol could effectively alleviate the damage from low-temperature stress. Further, we found that transgenic apple callus and tobacco overexpressing MdGolS5 showed strong cold tolerance. Specifically, the activities of antioxidant enzymes such as superoxide dismutase and GolS in transgenic tobacco overexpressing MdGolS5 increased under low-temperature treatment at -2 degrees C, and the contents of malondialdehyde, superoxide anion, and hydrogen peroxide were significantly lower than those of wild type tobacco. Moreover, large amounts of proline, galactinol, and raffinose were accumulated. In addition, the expression levels of cold-responsive genes MdCBF1, MdCBF2, MdCBF3, and MdCOR47 were significantly up-regulated in transgenic tobacco, further confirming the important role of MdGolS5 in regulating plant cold adaptation. In summary, this study not only revealed the direct effect of exogenous galactinol on the low-temperature protection of apple saplings for the first time, but also explored a new mechanism of raffinose family oligosaccharides anabolism in plant low-temperature adaptation through overexpression of MdGolS5. These results provide a theoretical basis for the genetic improvement of apple cold resistance.

Sodium liquid metal battery has attracted attention for large-scale energy storage applications due to its low-cost, long-lifespan and high-safety. However, the self-discharging caused by sodium dissolving in the molten salt electrolyte reduces the efficiency of the battery and restricts the practical development of this chemistry. In this work, a low-melting point multi-cationic electrolyte (LiCl-NaCl-KCl) was designed to inhibit the dissolution of sodium in the electrolyte. The displacement reaction of Na and molten LiCl at high temperature were revealed for the first time, and the mechanism of improving battery performance was demonstrated in the Na| LiCl-NaCl-KCl |Sb-Bi batteries. Based on the displacement reaction mechanisms, the Na||Bi9Sb cell based on LiCl-KCl (54:46 mol%) electrolyte, without NaCl at the initial state, was constructed, which exhibited high coulombic efficiency of over 98 % and excellent cyclic performance (similar to 100 % capacity retention after 2500 cycles) at 450 degrees C. This work provides a unique idea of electrolyte design that can both inhibit the dissolution of metals in molten salts and ensure long-term stable battery operation by using electrolyte-electrode interactions, and provides a new way for the practical development of low-cost and long-lifespan liquid metal battery energy storage technology.

Long-cycle-life, high-safety liquid metal batteries (LMBs) are considered competitive alternatives for large-scale energy storage applications. LMBs typically operate at high temperatures, and reducing their operating temperature has been a focus of research. In this study, we adopt a multi-cation molten salt LiCl-KCl-CsCl as the electrolyte for LMBs and achieve the stable operation of Li|LiCl-KCl-CsCl|Bi battery at 300 degrees C for the first time. However, the lower operating temperature significantly deteriorates the kinetic performance, resulting in a capacity utilization of only about 30 %. To address this issue, we apply a certain intensity of magnetic field to the battery using Helmholtz coils, which increases the capacity utilization to 100 %. This study combines the strategy of low-temperature LMBs with external magnetic field regulation, not only achieving a low operating temperature but also ensuring complete capacity release. Furthermore, this approach paves the way for the potential use of permanent magnets within battery modules to provide the magnetic field environment, without the risk of demagnetization.

Sodium-based liquid metal batteries are well suited for stationary energy storage due to their long life, intrinsic safety, and ease of scale-up. However, the irreversible alloying reaction between the positive current collector (PCC) and the cathodes at high temperatures leads to severe capacity degradation of the battery, severely limiting its scale-up application. In this work, a Bi-Sb-Sn alloy cathode based on a synergistic stabilization mechanism was designed for the first time. Due to the density difference of Bi, Sb, and Sn and the compatibility difference of Bi and Sn with the PCC, a part of Bi and Sn is spontaneously distributed in the region close to the PCC. The protection of Sb is realized by blocking the contact of Sb with the PCC as well as removing the PCC material dissolved in the cathode to prevent the loss of active material. Based on such protection, the Na||Bi36Sb24Sn40 cell maintained 99% Coulombic efficiency for 450 cycles at a rate of 0.75 C, with a capacity retention of 99.56% and a capacity decay rate of 0.001% per cycle. In addition, the interaction of Bi, Sb, and Sn during discharge also promotes capacity release and energy efficiency. At 0.3 C, the Na||Bi36Sb24Sn40 cell achieved 89% capacity utilization and 82% energy efficiency. These results provide an idea for the design of other batteries based on liquid metal electrodes.

Liquid metal battery (LMB) is one of the most competitive large-scale energy storage technologies due to its lowcost, long-lifespan, and high -safety. However, the low energy efficiency of the battery is currently one of the major challenges hindering its application process. The problem of poor wettability of the cathode liquid alloy is exacerbated by the design of the conventional planar structure of the positive collector. And the resulting interfacial mass transfer modes are inefficient. These lead to slow electrode reaction kinetics and large internal polarization. To address this issue, a novel array current collector suitable for LMB was designed here for the first time. The unique structure of the collector greatly increases the effective reaction area at the electrolyte/cathode and the contact area of the cathode/collector, providing more efficient nucleation and growth modes of the products as well as richer ionic mass-transfer channels, thus accelerating the electrode reaction kinetics. Benefiting from the application of the array current collector, the voltage efficiency of Li||Sb-Sn LMBs with a capacity of 20 Ah at 0.5C rate is increased by 4.8 %. Meanwhile, an average voltage efficiency of - 94.7 % and an average energy efficiency of - 92.2 % are achieved at 0.1C, which is the highest efficiency among the most promising LMB systems known to date. These encouraging results provide new directions for the design of highperformance LMBs and further promote the practical process of LMBs.

Melatonin is an important regulator of fruit growth and development. To explore the physiological mechanism whereby preharvest melatonin application regulates the polyphenol content of ‘Yuluxiang’ pear peel, we sprayed 0.1 mM melatonin during the first fruit expansion and early color change periods, and the control group were sprinkled with fresh water. Then, we measured the contents of anthocyanin, lignin, and major monomeric phenolics and the activities of key enzymes associated with phenolic metabolism. The results showed that melatonin application significantly increased the content of total phenolics, total flavonoids, total anthocyanins, and lignin in the peel from the color change to mature development stages. Near maturity, the activities of all key enzymes, except dihydroflavonol-4-reductase, were higher than those in the control samples, but significant differences in enzyme activity occurred at different time points. Compared with the control group, the fruit peels of the melatonin-treated plants exhibited a higher antioxidant activity and accumulated more flavonols. Thus, preharvest spraying of melatonin can alter the activity of key enzymes associated with phenolic metabolism, increasing the total phenol, flavonoid, anthocyanin, and lignin contents, which in turn, affects the color, strength, and antioxidant capacity of pear peels.

为给梨树合理施肥提供理论依据,以五九香梨树为试材,在关键发育期进行整株取样,测定植株各部分不同营养元素的含量,计算各营养元素的需求量,研究其需求规律.结果表明,常量元素的年需求比例由高到低依次为氮(N)、钙(Ca)、钾(K)、磷(P)、镁(Mg),微量元素的年需求比例由高到低依次为铁(Fe)、锌(Zn)、锰(Mn)、硼(B)、铜(Cu).在萌芽开花前和开花坐果期,常量元素需求比例最高的为N,微量元素需求比例最高的为B;在幼果生长期,常量元素需求比例最高的为K,微量元素需求比例最高的为Zn;在缓慢生长期,常量元素需求比例最高的为Ca,微量元素需求比例最高的为Fe;果实采收前和树体休眠前,常量元素需求比例最高的为N,微量元素需求比例最高的为Fe.各元素在不同发育时期的吸收分配比例结果显示,N、P、K、Ca、Mg、Cu等的最高时期为果实采收前,Fe和Zn的最高时期为缓慢生长期,Mn的最高时期为树体休眠前,B的最高时期为开花坐果期.生产1t五九香梨果实的营养元素需求量为N 4.26 kg、P 2.64 kg、K 3.03 kg、Ca 3.93 kg、Mg 1.19 kg、Cu 2.02 g、Fe 65.86 g、Zn 23.09 g、Mn 18.03 g、B 18.00 g.

Liquid metal batteries (LMBs), with the merits of long lifespan and low cost, are deemed as one of the most promising energy storage technologies for large-scale energy storage applications due to the use of liquid metal electrodes and molten salt electrolytes. However, the consequent problem is that the poor wettability between graphite-based collectors and the liquid metal/alloy electrodes leads to large contact resistance, which limits the efficiency and stability of the battery. In this work, a transition layer in situ formed on a graphite-based positive electrode current collector by Ti additive is designed for the first time, which increases the wettability between the positive alloy and the current collector and improves the voltage efficiency of the Li||Sb-Sn cell from 85.6 to 88.4%. These results provide new ideas for the design of high-efficiency LMBs.

Liquid metal batteries (LMBs) employ liquid metal as electrodes and inorganic molten salt as electrolytes, which circumvent the capacity degradation mechanism inherent in conventional batteries and are regarded as a promising alternative for grid-level energy storage. LMBs need to operate at high temperatures (typically 500-550 degrees C), and it is of paramount importance to reduce the operating temperature. This work abandons the conventional lithium halide mixture electrolytes, and innovatively adopts lithium halide-potassium halide electrolytes, which are previously deemed unstable during the operation of LMBs. First, the Li|LiCl-KCl|Bi bat-teries are constructed, achieving stable operation at 410 degrees C with a remarkable capacity retention of 93.6% after 1100 cycles. Furthermore, the Li|LiCl-LiBr-KBr|Bi batteries are designed, demonstrating stable operation at 350 degrees C without capacity degradation after 660 cycles. The low working temperature significantly improves the Coulombic efficiency (up to 99.96%, the highest value among all reported LMBs to date) and facilitates the battery module to achieve "self-heating". Additionally, the mechanism of the displacement reaction between Li and K+ and the migration kinetics of Li atoms in LiBi/Li3Bi intermetallic compounds are analyzed. This work establishes liquid metal batteries with the advantages of low working temperature, high cycle stability, high Coulombic efficiency, low cost, and large capacity, which effectively promotes the development and practical application of LMBs.

In order to explore the adaptability of tree shape and varieties the middle and lower reaches of the Yangtze River,and realize the matching of improved varieties and methods and labor-saving and efficient cultivation of pears,we investigated the growth results of different varieties with different tree shapes,such as new shoot growth potential,germination rate,branching ability,proportion of medium and short branches,early fruiting ability and yield.The fuzzy evaluation method is used for systematic evaluation and analysis.The comprehensive evaluation values of varieties with horizontal trellis cultivation from high to low were‘Cuiyu’pear,‘Cuiguan’pear and‘Xinyu’pear,while the open-center shape was‘Huanghua’pear,‘Cuiyu’pear,‘Cuiguan’pear and‘Mixue’pear.The performance of‘Cuiguan’pear is better than‘Hosui’pear with the“Y”tree shape.The comprehensive evaluation values of‘Hosui’pear,‘Akizuki’pear and‘Wakahikari’pear with cylindrical tree shape are low,which are 0.564,0.615 and 0.621 respectively.There are 6 varieties with comprehensive evaluation values above 0.70,including‘Xinyu’pear,‘Qingxiang’pear,‘Cuiyu’pear,‘Huangguan’pear,‘Wancui’pear and‘Cuiguan’pear.After adopting different tree shapes,the comprehensive evaluation values of‘Cuiguan’pear from high to low are as follows,open-center shape＞“3+1”tree shape＞horizontal trellis cultivation＞cylindrical shape＞downward-arrowhead-shaped＞“Y”shape＞spindle shape.The comprehensive evaluation value of‘Cuiyu’pear with cylindrical tree shape is more than 0.70.The downward-arrowhead-shaped and“3+1”tree shape are suitable for the cultivation of‘Hosui’pear.The comprehensive ranking of‘Huanghua’pear with different tree shapes from top to bottom is open-center shape and cylindrical shape.The cylindrical shape is more suitable for the lightened and simplified cultivation of‘Sucui 1’than the spindle tree shape.To sum up,horizontal trellis cultivation,cylindrical shape,“3+1”tree shape,downward-arrowhead-shaped,open-center shape can be used as labor-saving and efficient cultivation tree shape,which can be popularized and applied in the middle and lower reaches of the Yangtze River.In production,the tree shape should be selected according to the characteristics of different cultivation varieties.

Althoughliquid metal batteries (LMBs) have garnered significantattention for their potential in sustainable energy storage, theirpractical applications are limited by a low working voltage. A novelZn-based positive electrode utilizing displacement reaction is presentedherein to enhance the voltage of LMBs. The compatibility between LiCl-KCland Zn was investigated, revealing that a complete displacement reactionwould reduce the active components of the battery. By adding a smallamount of Bi to Zn, both the stability and cycling performance ofbatteries can be improved. Specifically, the Li||LiCl-KCl||Bi3Zn7 battery exhibits a high discharge voltage of0.93 V at 100 mA cm(-2) and achieves an energy densityof 202.04 Wh kg(-1), which has a lower material costof 50.29 $ kW h(-1). These interesting results providenew ideas for the design of new system LMBs. The schematic of charge-dischargereaction of Li||Zn-Bibattery based on the displacement reaction.

Melatonin (MT), an indoleamine compound, has a pleiotropic effect on plant growth and development and can regulate the quality of tree fruit. Systematic research on the effect of preharvest MT spraying on pear fruit quality and technical solutions for MT application to regulate pear fruit quality are still lacking. Thus, here we aimed to evaluate the effects of different spraying times, concentrations, and exogenous MT application times on 'Yuluxiang' pear fruit quality. Our results showed that the single fruit weight and vertical and horizontal diameters of pear fruit sprayed with MT twice at 30 and 90 d after full bloom were the largest, and the red and green values of the treatment were the highest. MT-treated pears had higher contents of total soluble solids, soluble sugar, sucrose, sorbitol, fructose, and glucose and lower contents of titratable acid, malic acid, and citric acid. Moreover, exogenous MT treatment increased the pear peel strength. Based on the principal component analysis of 10 fruit quality indices, the suitable periods for MT spraying on 'Yuluxiang' pears were 30 and 90 d after full bloom, the suitable concentration was 100 μmol/L, and the suitable number of times was two. This study provides a theoretical reference for optimizing MT application and improving pear fruit quality.

Liquid metal batteries (LMBs) have the advantages of low cost and long life, which are especially suitable for static energy storage in power grids. Understanding the relationship between inconsistent parameter distributions, topological connections, and battery module performance is important for designing and optimization of battery packs. This paper investigates the effect of differences in cell parameters and module design parameters on the current distribution in parallel LMB modules. Based on the equivalent circuit model (ECM), a parallel module with a Z-shaped topology is built and configured as a reference model that can be invoked in an interactive manner. The analytical solution of the current distribution is deduced under the assumption of identical cells within the module, the results revealed that the effect of the interconnection resistance on the current distribution depends mainly on its ratio to battery resistance. Design of experiments (DOE) is used to design 81 sets of experiments with the distribution dispersion of battery SOC and current as response variables and four parameters of capacity difference, internal resistance difference, interconnected resistance, and the number of parallel cells as factors, and $10^{2}$ Monte Carlo simulations are performed on the referenced model in each set of experiments to obtains highly reliable distribution results. The results module structural parameters are the main factors influencing differences in cell current distribution and an appropriate range of cell inconsistency has a positive effect on parallel modules. This research will provide a reference basis for LMB module design to reduce the inconsistency of batteries within the module.

Green and efficient recycling technology is an important challenge that restricts the large-scale application and sustainable development of energy storage batteries. Liquid metal batteries (LMBs) are considered to be the ideal choice for large-scale stationary energy storage due to the inherent advantages of low cost, long lifetime, and high safety. Herein, a full-lifetime recycling and reutilization strategy for LMBs based on facile molten salt electrochemical processes is proposed for the first time, which is verified in the Li||Sn-Sb LMBs. The achieved recycling efficiencies of anode, cathode, and electrolyte materials are similar to 80, similar to 94, and similar to 60%, respectively. The Li||Sb-Sn LMBs based on recycled materials are constructed and exhibit excellent cyclic performance and a 99.2% capacity retention after 1500 cycles. Moreover, the estimated levelized cost of energy of the LMBs based on the recycling strategy can be reduced by 0.021 $ kW h(-1), which is a 47.7% reduction. This work provides a new strategy for the full-lifetime recycling and reutilization of LMBs and a new roadmap for the sustainable development of electrochemical energy storage technology.

为了明确玉露香梨果实品质与矿质营养之间的关系,以期通过施肥技术来调控果实品质.以玉露香梨为研究对象,对果实发育过程中叶片、果实的矿质元素含量和果实品质进行了动态分析.结果表明:玉露香梨果实发育期,叶片中N、Mg元素含量总体呈下降趋势,B、Zn、Mn元素含量总体呈上升趋势,K和Fe元素含量总体呈先下降后上升趋势,Ca元素含量在盛花后65～95 d和盛花后110～140 d各出现1个吸收高峰,P和Cu元素含量变化不明显;果实中N和K元素含量总体呈下降趋势,P、Ca、Mg和Cu元素含量呈先下降后上升最后下降的趋势,B、Zn、Mn和Fe元素在盛花后65～95 d和盛花后110～140 d出现2个吸收高峰.玉露香梨叶片和果实中的N、K、Ca、Zn等元素含量与单果重、果形指数、可溶性固形物含量、可滴定酸含量和果肉硬度存在较高的关联度.综合果实品质指标与矿质元素含量之间的关联分析,果实发育初期是调控N和K元素含量的关键时期,盛花后65 d前后是调控P、B、Zn、Mn和Fe元素含量的关键时期,盛花后95 d前后是调控Ca元素含量的关键时期.

为明确玉露香梨对拉枝处理的营养分配和内源激素生理响应,以玉露香梨为试材,重点分析了 70.拉枝处理后叶片内源激素、叶片矿质营养含量变化及成花情况.结果表明:拉枝处理显著提高了叶片中P、K元素含量,显著降低了 N、Ca、Zn元素含量,Mg、B元素含量无显著变化.拉枝处理显著提高了玉米素核苷(ZR)含量,比对照增加54.31％;显著降低了脱落酸(ABA)、生长素(TAA)、赤霉素(GA3)含量,分别比对照降低36.65％、53.71％、29.62％;同时拉枝处理显著提高了 ZR/ABA、ZR/IAA和ZR/GA3比值,分别是对照的2.42、3.24、2.15倍.综上所述,叶片中低N含量高P、K含量,较高水平ZR含量,较高ZR/ABA、ZR/IAA和ZR/GA3比值均有利于花芽分化,促进玉露香梨成花.

梨属于异花传粉作物,多数栽培品种自花不实或自花结实率极低,需要配置相应比例的其他梨品种作为授粉树进行互相传粉,完成授粉受精过程,以保证产量.如花期遇到大风、阴雨或低温天气,会造成授粉受精不良,进而导致"花而不实"且后期发生大量生理落果现象,为避免恶劣天气环境影响,常需要通过人工辅助授粉来保证授粉受精的质量,进而保证当年的产量.现将相关技术总结如下,仅供同行参考.

Electrochemical energy storage is becoming one of the most promising solution for renewable energy integration. Liquid metal battery is a prospective battery chemistry for stationary energy storage due to its low cost and long lifespan. However, the flat voltage platform and low working voltage easily introduce relative errors, resulting in challenges in battery state of charge (SOC) estimation. Meanwhile, practical applications of liquid metal batteries require efficient SOC estimation algorithms for massively parallel computing. Thus, in this paper, an improved sliding mode observer (ISMO) is proposed for liquid metal battery SOC estimation to meet the challenges. Firstly, based on a combined equivalent circuit model, the forgetting factor recursive least square algorithm is utilized to identify model parameters in the whole working range. Secondly, a direct differentiation method is put forward to deal with the linearization between the open circuit voltage and the SOC. Finally, a novel adaptive law is proposed to accelerate the convergence, restrict the probable large chattering and improve the estimation accuracy of the algorithm. Compared to the conventional model-based methods, the proposed ISMO exhibits faster convergence, higher accuracy, stronger robustness and lower computational cost in simulations, which indicates an industrialization prospect.

Sodium-based batteries are very promising for large-scale applications in near future, thanks to the great abundance and low cost of sodium. Herein, a high-performance liquid metal battery with a negative electrode of metallic sodium is developed. As the metallic sodium has a low melting point (∼ 98°C) and weak corrosion to ceramic seals, the sodium liquid metal batteries (Na-LMBs) offer the merits of low operating temperature, low cost, long lifespan and high safety. However, sodium metal has a high solubility in the electrolyte of single-cationic molten sodium halide mixtures such as NaF-NaCl-NaI due to a high melting point above 500°C, resulting in high self-discharge and low coulombic efficiency. In this work, a multi-cationic ternary molten chloride salt mixture LiCl-NaCl-KCl (59:5:36 mol %) with a melting point lower than 400°C was designed as the electrolyte, which effectively inhibits the dissolution of sodium in the electrolyte. Further, by adopting a dual-active Bi9Sb alloy positive electrode, the active material utilization was improved. At 100 mA cm−2, the battery ran stably over 700 cycles at 450°C with a coulombic efficiency of 97%, and active material utilization of about 80%. The battery also exhibited decent rate performance within the current densities of 100-1000 mA cm−2. The calculation based on a 1 MW/5 MWh demo energy storage plant indicates that the estimated Levelized Cost of Storage (LCOS) of the Na-LMB is lower than 0.029 $/kWh. These results demonstrate the Na-LMB as a promising technology for grid-scale energy storage applications.