To address the problems of artificial apple thinning, which are time-consuming, labor-intensive, and inefficient, this study examined the fruit thinning effect and mechanism of spraying metamitron at the young fruit stage on Gala apples grown on dwarfing inter-stocks. The results showed that spraying 500mg·L-1metamitron twice, at 3 mm and 9 mm fruit diameters, significantly reduced the fruit setting rate of inflorescences and flowers, thereby increasing the single fruit ratio. The photosynthetic parameter (Pn) and chlorophyll fluorescence parameters (Fv/Fm, ΦPSII, qP, and NPQ) were significantly inhibited by the treatment, resulting in a noticeable decrease in soluble sugar content. The treatment significantly increased abscisic acid (ABA) content and decreased the (Z+GA3+IAA)/ABA ratio. These results suggest that metamitron effectively thins apple fruit, with its mechanism likely related to damage to the leaf PSII reaction center structure, obstruction of photosynthetic electron transfer, insufficient soluble carbohydrate supply due to reduced photosynthetic rate, increased ABA content, and decreased auxin hormone/ABA ratio.

Non-bagging apple cultivation, which is time-saving, labor-saving, and cost-effective, represents the future direction of apple cultivation in China. However, compared with bagging cultivation, it degrades fruit appearance quality, characterized by rough peels and dull colors, with the underlying physiological and molecular mechanisms remaining unclear. This study used ‘Tianhong 2’ Fuji apples, grafted onto SH dwarfing rootstock, and integrated transcriptomics–metabolomics to explore these mechanisms. Results showed that non-bagging-cultivated apple peels had higher chlorophyll and carotenoid contents but lower anthocyanin content than those of bagging-cultivated ones. Transcriptome sequencing identified 1571 differentially expressed genes (DEGs: 1269 upregulated, 302 downregulated). Functional analysis revealed that the decline in fruit appearance quality was primarily associated with secondary metabolite biosynthesis, lipid metabolism, and carbohydrate metabolism, and 34 candidate genes were identified. Metabolomic analysis detected 394 differentially expressed metabolites (DEMs), 38 of which were closely related to the non-bagging-induced appearance degradation, mainly lipids, organic oxygen compounds, and organic acids and their derivatives. Integrated analysis of DEGs and DEMs indicated the involvement of multiple critical metabolic pathways, including cutin, suberin and wax biosynthesis; starch and sucrose metabolism; cyanoamino acid metabolism; and phenylpropanoid and flavonoid biosynthesis. Compared with bagging-cultivated apples, non-bagging-cultivated apples exhibited faster starch degradation and higher soluble sugar accumulation. Additionally, the accumulation of specific metabolites [e.g., quercetin (HMDB0005794, HMDB03249, LMPK12112097), and suberin components (LMFA01170020, LMFA01050437, HMDB0031885)], along with elevated organic acid levels, contributed to peel roughness and dull coloration. These findings further enrich the theoretical basis for the formation of fruit quality in Fuji apples under non-bagging cultivation and provide valuable theoretical guidance for the practical application of this cultivation mode.

Improving apple peel color has been an important objective in apple production. To better understand the effect and mechanism of the combined application of urea and FA (fulvic acid) regulation of anthocyanin biosynthesis, a field experiment was performed in 2022 and 2023, respectively, under five treatments of urea + FA (CK, urea only; FA50, urea + 50 kg ha−1 FA; FA100, urea + 100 kg ha−1 FA; FA150, urea + 150 kg ha−1 FA; FA200, urea + 200 kg ha−1 FA), using isotope (13C and 15N) marking to analyze the changes in carbon (C) and nitrogen (N) nutrient distribution as well as anthocyanin biosynthesis in fruits. We observed that, under FA application conditions, anthocyanin content in the peel was elevated in both years, with increases of 15.98~52.88% in 2022 and 15.93~52.94% in 2023. The best promotion effects were observed under FA150 treatment. Apart from the expression levels of anthocyanin biosynthesis-related genes and transcription factors in the apple peel, this positive effect on anthocyanin content induced by FA addition was also found to be associated with the optimization of C and N distribution in leaves and fruits. On the one hand, the application of FA not only enhanced leaf photosynthetic-related indexes (such as Pn, Gs, and Rubisco activity) and influenced (increased) S6PDH, SPS, and SS activities in leaves, but also elevated fruit sugar metabolism-related enzyme (SDH, SS-c, AI, and NI) activity and upregulated fruit stalk sugar transporter (MdSOT1, MdSOT3, MdSUT1 and MdSUT4) gene expression, which ultimately promoted the synthesis and the leaf to fruit transport of photosynthates, thus promoting 13C-photosynthate accumulation in fruits. On the other hand, FA application elevated leaves’ N metabolism-related enzyme (GS and GOGAT) activity and optimized 15N distribution in leaves and fruits. Moreover, we also observed that FA application altered the fate of N fertilizer in apple orchards, showed an elevation in apple tree 15NUE and soil 15N residuals and showed a decrease in soil 15N loss. In summary, the appropriate application of FA150 (urea + 150 kg ha−1) synergistically optimized C and N nutrient distribution, and promoted anthocyanin biosynthesis in apple trees.

苹果园春季管理措施直接影响当年树体的生长发育与产量.总结了苹果花前复剪、高效授粉、疏花疏果、花期霜冻防控以及病虫害防控等春季管理关键技术,供生产参考.

Seaweed extracts, which are naturally degradable and environmentally friendly, have become important components of organic fertilizers for fruit. In this study, the effects of seaweed-extract-based organic fertilizers on the levels of mineral elements, sugar–acid components, and hormones in ‘Fuji’ apples were evaluated. Eleven-year-old ‘Fuji’ apple (‘Yanfu 3’/M9/Malus robusta) trees were sprayed with seaweed-extract-based fertilizers SE1 (contained ≥20 g/L of algal polysaccharides, ≥100 g/L of amino acids, and ≥30 g/L of EDTA-Ca) and SE2 (contained ≥100 g/L of algal polysaccharides, ≥160 g/L of Ca, and ≥10 g/L of Mg) from early May to early October at two-week intervals in 2020. Water spraying was used as a control treatment. The preliminary results showed that SE1 and SE2 significantly increased the net photosynthetic rate, chlorophyll content and Rubisco enzyme activity in ‘Fuji’ apple leaves. SE1 and SE2 improved the quality of ‘Fuji’ apples. Compared to the single-fruit weight, soluble solid content (SSC), soluble sugar content, sugar–acid ratio, vitamin C (VC) content, and free amino acid content of control apples, those of SE1-treated and SE2-treated apples increased by 10.74% and 8.94%, 12.16% and 9.76%, 21.96% and 11.90%, 45.12% and 28.55%, 56.12% and 47.96%, and 17.15% and 13.42%, respectively. SE1 and SE2 significantly improved the levels of fructose, glucose, sucrose, and sorbitol, but decreased the levels of malic acid, oxalic acid, and tartaric acid in ‘Fuji’ apples. Meanwhile, SE1 and SE2 increased the levels of potassium, calcium, magnesium, iron, zinc, and boron in ‘Fuji’ apples. SE1 and SE2 significantly improved the levels of indole-3-acetic acid, zeatin riboside, and gibberellic acid, but significantly decreased the level of abscisic acid in ‘Fuji’ apples. In conclusion, spraying seaweed-extract-based foliar fertilizer is beneficial to the nutrient accumulation and flavor development in ‘Fuji’ apples.

The experiment was conducted at the Taidong Base of Shandong Institute of Pomology, Tai’an City, Shandong Province, China, from May to October 2022. Using Fuji Apple Tianhong.2/SH/Malus robusta (M. robusta) as experimental materials, the differences and mechanisms of the effects of non-bagging and bagging cultivation on the growth and changes in some substance content of Fuji apple fruits were studied. The results showed that compared with bagging, non-bagging cultivation increased single fruit weight and decreased fruit shape index, increased fruit sugar content, reduced acid content, and increased taste. It increased the content of vitamin C (VC) and protein in the fruit, increased the types and content of aromatic components in the fruit, significantly increased the activity of sugar- and acid-related enzymes, and improved the antioxidant capacity of the fruit. Compared to bagging cultivation, non-bagging cultivation improved the weight, taste (sugar acid ratio), and aroma of Fuji fruit, which is related to increasing the content of auxin (IAA), cytokinin (ZR), and salicylic acid (SA) and reducing the content of abscisic acid (ABA) in the fruit, as well as increasing the content of medium and trace elements calcium (Ca), iron (Fe), manganese (Mg), and boron (B). One of the mechanisms involved is the significant increase in gene expression related to phenylpropanoid biosynthesis, pentose and glucuronate interconversion, starch and sucrose metabolism, zeatin biosynthesis, microtubules, motor proteins microtubule movement, xyloglucan metabolic process, cell division, and peroxidase activity. In short, non-bagging cultivation is more conducive to improving the intrinsic quality and flavor development of Fuji apples, and one of the mechanisms is that non-bagging cultivation is beneficial for increasing the expression of related genes.

Marigold can protect crops against soil-borne diseases. However, the effects of intercropping with marigold on apple rhizosphere soils are not known. In this study, we investigated the metabolite profiles and bacterial community structures in rhizosphere soils of the apple-marigold intercropping system by high-throughput sequencing and soil metabolomics. The results show that intercropping marigold could significantly enhance soil moisture, nitrogen, and enzyme activities compared with clean tillage. The soil metabolite profiles and the soil bacterial community structures in the rhizosphere soils were different between the inter-and mono-cropping systems. Among nine metabolites, carbohydrates were more increased in the intercropping system than in the monocropping system. Pathway enrichment analysis revealed that the greatest differential, in terms of metabolic pathway, was starch and sucrose metabolism. Moreover, intercropping marigold significantly increased the relative abundance of plant growth promoting bacteria in rhizosphere soils, such as Rhizobiales, Pseudomonadales, and Bacillales. These results indicate that marigold intercropping positively affected the apple orchard's soil quality and may provide a new intercropping technique to improve soil fertility in orchards and promote plant growth.

In recent years, with the global climate change, the intensity, frequency and duration of drought have increased significantly, which has become the main limiting factor for agricultural development in many areas. Glycine betaine (GB) is an effective stress-resistant substance. In this experiment, the effects of the genetic engineering of GB synthesis on photosynthetic apparatus of tobacco under drought stress were studied using transgenic tobacco (T) accumulating GB and wild-type tobacco (K326, WT). Potted tobaccos were subjected to drought stress (controlled irrigation, 25 °C ± 1 °C, a relative humidity: 75–80%) for 9 days, photosynthetic gas exchange parameters, chlorophyll a fluorescence, structure of chloroplast and thylakoid membrane, and protein function of thylakoid membrane were examined under different drought stress time (days). The results showed that T tobacco could accumulate GB and the accumulated GB improved the resistance of the photosynthetic apparatus to drought stress. Under drought stress, the damage of chloroplast and thylakoid lamellae in T tobacco was less than that in WT tobacco, the accumulation of GB in T tobacco could maintain the stability of thylakoid membrane, improved the unsaturated fatty acid index (IUFA) of thylakoid membrane lipid, increased the contents of digalactosyl diacylglycerol (DGDG) and phosphatidylglycerol (PG), and decreased the ratio of monogalactosyl diaylglycerol (MGDG) to DGDG. In addition, under drought stress, the accumulation of GB in T tobacco alleviated the photo-inhibition of PSII, and the increase of xanthophyll cycle de-epoxidation may be one of the reasons for the enhancement of PSII function.

以红色苹果品种嘎拉、红将军和富士为试材,研究了果实不套袋生产对果实品质的影响.结果表明,与套袋栽培相比,不套袋栽培的果实外观品质降低,果实着色指数、光洁度指数明显低于套袋果,红色度低于套袋果,黄色度高于套袋果.不套袋栽培减轻了红将军和富士苹果苦痘病的发生,病果率分别由8.0％、6.0％降低到3.0％、2.0％,富士的单果重增加,对嘎拉和红将军的单果重影响不显著;不套袋提高了嘎拉和红将军果实的硬度,但减小了富士果实的硬度;提高了3个品种的可溶性固形物含量、可溶性糖含量,减少了可滴定酸含量,提高了果实甜味口感.

This study was conducted at the Taidong Base of the Shandong Institute of Pomology, Tai’an City, Shandong Province, China, from May to October 2020. The effects of spraying calcium fertilizer on the photosynthetic characteristics, mineral element content, sugar and acid metabolism, and quality of apples were assessed. Fuji Apple Tianhong.2/SH/Malus robusta (M. robusta) was treated with the calcium fertilizers Niucui (Ca ≥ 100 g/L, B: 1–10 g/L) and Naipu 9 (Ca: 90 g/L, Mg: 21 g/L, N: 110 g/L) at the young fruit stage (25 May), the expansion stage (5 July), and the coloring stage (25 September). Water was sprayed as the control application. The results revealed that spraying calcium fertilizer increased the chloroplast pigment content and photosynthetic capacity of the apple leaves. Compared with the control, the net photosynthetic rate of apple leaves sprayed with Niucui increased by 4.3–34.6%, and that of leaves sprayed with Naipu 9 increased by 15.0–57.4%. Spraying calcium fertilizer promoted the accumulation of Ca, Mg, and B mineral elements in leaves and fruits while inhibiting the accumulation of Cu. Spraying calcium fertilizer improved the quality of apple fruit. Compared to the control fruit, the single fruit weight, fruit hardness, soluble solid content, and Vitamin C content of fruit sprayed with Niucui and Naipu 9 increased by 6.5 and 12.1%, 3.6 and 16.1%, 6.3 and 12.0%, and 30.5 and 29.4%, respectively. Spraying calcium fertilizer increased the sugar content and decreased the acid content of the apples. Naipu 9 was more effective at increasing fruit sugar content, especially sucrose and sorbitol, while Niucui was more effective at reducing the acid content, especially malic acid. This was observed because Naipu 9 increased the sugar metabolism enzyme activity, while Niucui increased the acid decomposition-related enzyme activity. In conclusion, according to the nutrition quality and flavor of the fruit, Naipu 9 application was determined to be the best fertilizer for the Fuji apple.

为进一步探讨不套袋与套袋对苹果品质影响的机理,以8年生'富士'苹果('天红2号'/'M26'/八棱海棠)为试验材料,共设5个套袋密度处理(不套袋、套袋1/3的果实、套袋1/2的果实、套袋2/3的果实、套袋所有果实),所用果袋为小林果袋(双层纸袋,内红外棕),研究不同套袋密度对果实套袋前(6月19日)、套袋后2天(6月21日)、套袋中(8月22日和9月27日)、摘袋后2天(10月9日)和采收后1天(11月3日)苹果叶片光合特性的影响.结果表明,套袋不仅降低了苹果树冠层内的光照强度,而且显著降低了叶片的光合速率,而随着套袋密度的增加,苹果树冠层内的净光合速率显著降低,尤其是在8月和9月.5个处理的冠层光强、气孔导度、叶绿素含量、类胡萝卜素含量和叶片比重的变化与净光合速率的变化基本一致,说明果实套袋导致叶片光合性能下降.套袋苹果光合速率的降低是由气孔导度的降低引起的,这可能与光照强度降低有关;而在9月光合速率的降低还可能与高温弱光,套袋苹果叶片出现非气孔限制有关.

The frequent and massive use of pesticides has led to pesticide residues in apricot, threatening food safety and human health. A reliable and simple modified QuEChERS method with ultra-performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 11 pesticides in apricot. Method validation indicated that satisfied linearity (R 2 ≥ 0.9959), accuracy (recoveries of 72–119%), sensitivity (limits of detection, 0.03–0.30 μg/kg; limits of quantification, 0.13–1.00 μg/kg), and precision (relative standard deviations ≤ 11.9%), and matrix effects were 0.89–1.13. Apricot samples from different ecological regions in China were collected and tested using the proposed methods. Monitoring results were used to assess the dietary intake risk of Chinese populations of different ages and genders. Dietary risk assessment revealed that the risk quotients were 0.003–1.184% for different gender and age groups in China, indicating none unacceptable public health risk for general population. This work was thus significant in developing a simpler, more efficient and economical analysis method and food safety risks of the 11 pesticides on apricot and facilitated the establishment of maximum residue limits.

Many studies have demonstrated that anthocyanin synthesis in apple peel is induced by light, but the color of bagged apple peel continues to change under dark conditions after light induction has not been characterized. Here, transcriptional and metabolic changes associated with changes in apple peel coloration in the dark after different light induction treatments were studied. Apple pericarp can achieve a normal color under complete darkness followed by light induction. Metabolomics analysis indicated that the expression levels of cyanidin-3-O-galactoside and cyanidin-3-O-glucoside were high, which might be associated with the red color development of apple peel. Transcriptome analysis revealed high expression levels of MdUFGTs, MdMYBs, and MdNACs, which might play a key role in light-induced anthocyanin accumulation under dark conditions. 13 key genes related to dark coloring after light induction was screened. The results of this study provide new insights into the mechanism of anthocyanin synthesis under dark conditions.

以7年生矮化中间砧苹果为试材,研究了不同材质树盘覆盖对土壤微生物丰度、群落结构和多样性的影响。高通量测序结果表明,防水园艺地布和塑膜覆盖处理提高了0—20 cm土层变形菌门的相对丰度和20—40 cm土层变形菌门的相对丰度,防水园艺地布处理还显著提高了土壤细菌Ace和Simpson指数。相较于防水、塑膜覆盖处理,透水园艺地布不仅提高了0—20 cm土层变形菌门、接合菌门的相对丰度,而且提高了土壤细菌Ace、Chao1和Simpson指数,降低了土壤真菌Ace、Chao1和Simpson指数。树状聚类图结果显示,树盘覆盖显著改变了土壤细菌和真菌群落结构,以透水园艺地布覆盖处理的改变最为显著。综合分析认为,不同覆盖措施均有利于提高土壤细菌群落的丰富度和多样性,降低土壤真菌群落的丰富度和多样性,优化土壤微生物群落结构,其中以透水园艺地布覆盖的效果最好。

以红将军/M26、红将军/Mark和红将军/CG80等中间砧的不同砧穗组合为试材,研究不同矮化中间砧对红将军树体生长、光合及产量和品质的影响.结果表明,随着树龄的增长,不同砧穗组合树体树干粗度、树体总枝量逐年增加,其中以红将军/CG80树体粗度最大、树体总枝量最多,而红将军/M26树体粗度最小、树体总枝量最少;红将军的枝类组成在不同中间砧间均表现为长枝占比逐年降低,而短枝占比逐年提高的变化趋势,其中红将军/M26的树体短枝占比最高,长枝占比最低;不同中间砧对红将军叶片SPAD、净光合速率等的影响不同,均以红将军/M26组合的最高;从产量品质来看,不同砧穗组合在栽植第3年开始有产量,栽植第6年产量基本趋于稳定,红将军/M26组合的累计产量最高,根据综合稳产期各砧穗组合果实品质调查结果,红将军/M26苹果单果质量、果形指数、去皮硬度以及可溶性固形物含量均高于红将军/Mark、红将军/CG8.综上所述,红将军/M26中间砧组合的综合表现较优.

The presence of pesticide residues in apples raises serious health concerns. In this study, a novel, sensitive, highperformance method was developed to simultaneously analyze the residues of 14 pesticides in apples using modified QuEChERS sample pretreatment coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The optimized purification procedure demonstrated satisfactory recovery and precision for all the tested pesticides. The limits of detection (LOD) and quantification (LOQ) values of 14 pesticides in the apple matrix ranged from 0.03 mu g/kg to 0.3 mu g/kg and 0.1 mu g/kg to 1.0 mu g/kg, respectively. The proposed method detected six pesticides in the apple samples collected from 20 counties in China's major apple producing regions. Furthermore, the risk quotient (RQ, %) of the detected pesticides was evaluated by the national estimated acceptable daily intake. The RQs of six pesticides in Chinese people of different age groups were less than 100%.

[目的]研究天红2号苹果幼树至稳产期树体生长、产量和品质形成的动态,为天红2号苹果推广应用及优质高效生产提供理论基础.[方法]以2010年春季栽植的矮化中间砧红富士(天红2号/SH40/八棱海棠)苹果为试材,2011—2018年连续8年调查树体生长、枝类组成和果实产量、品质的变化.[结果]随着树龄的增长,树体高度、冠径、树干粗度、覆盖率以及总枝量均随着树龄增长而有不同程度的增加,栽植后前4年增长速度较快,之后通过修剪可控制树体的生长;随着树龄增长,短枝比例逐渐增加,长枝比例逐渐降低,栽植后5年树体枝类组成趋于稳定,短枝比例维持在65％左右,长枝比例维持在10％左右;随树龄的增加,产量逐年大幅度增加,栽植后第7年进入稳产期,年产量高达50 t/hm2左右,果实品质稳定性较好,在不同树龄间果实品质差异不显著.[结论]天红2号/SH40/八棱海棠具有树体结构合理、早实丰产、果实品质优等优点,适于在泰安地区推广应用.

建立了QuEChERS-超高效液相色谱-串联质谱(QuEChERS-UPLC-MS/MS)检测苹果中5种农药残留的分析方法.样品采用QuEChERS进行前处理,乙腈提取,经PSA、纳米氧化锆(Nano-ZrO2)和多壁碳纳米管(MWCNTs)组合净化,结合UPLC-MS/MS检测,外标法定量.结果表明,在0.005～0.5 mg/L的浓度范围内5种农药在苹果基质中的线性关系良好,R2≥0.9950;在0.05,0.5和5 mg/kg的添加水平下5种农药的平均回收率在78.1％～117.5％之间,相对标准偏差(RSDs)在1.8％～9.1％之间;定量限(LOQ)为0.1～2μg/kg.该方法适用于苹果中5种农药残留检测.

在新红将军和寒富苹果的近成熟期,研究不同采摘时间对果实品质的影响.结果表明,随采收期的推迟,新红将军单果重、着色指数逐渐增加,果形指数和可溶性固形物含量先增加后降低,光洁度和硬度逐渐降低;随采收期的推迟,寒富单果重逐渐提高,果形指数、着色指数及可溶性固形物含量先升高后降低,光洁度指数、硬度逐渐降低,综合各项指标认为,鲁中地区新红将军苹果的适宜采收期为9月30日,寒富苹果的适宜采收期为10月10日.

果树生产的机械化是实现果树产业现代化的关键方面,果树生产虽然已有较多机械的参与,但是农机农艺融合和适用性尚存在一定的问题.阐述了果树生产农业机械的产业现状和存在的问题,确定了适用于果树的农业机械适用性评价标准的原则,探讨了适用于果树的农业机械适用性评价标准,旨在为适用于果树的农业机械适用性标准体系提供借鉴.