'Katy' and 'Kuijin' apricots are the main cultivated varieties in Shandong province. The flavor of the fruit is mainly determined by sugars and acids, with soluble sugar components serving as important nutritional elements in fruits as well as crucial indicators of fruit sweetness and flavor quality. However, little is known about the changes in soluble sugar content, especially sucrose content, and the sucrose metabolism mechanism during the entire fruit growth and development process of 'Katy' and 'Kuijin' apricots. In this study, we first detected the changes in sucrose, fructose, and glucose content at nine fruit development stages of 'Katy' and 'Kuijin' apricots, and found that the stage of rapid accumulation of sucrose and fructose was from 56 days after full bloom (DAF) to 63 DAF. Therefore, we identified the key gene PaSS1 of sucrose synthase through transcriptome data screening, and further analyzed the function of the PaSS1 gene in fruit sucrose metabolism process using virus-induced gene silencing (VIGS) technology. Silencing the PaSS1 gene reduced the breakdown activity of sucrose synthase, increasing sucrose content while decreasing glucose and fructose content, delaying fruit coloring and ripening, indicating that the PaSS1 gene may regulate the ripening of apricot fruits. This study provides a theoretical basis for further research on the molecular mechanism of the PaSS1 gene in apricot fruit ripening process.

Bagging-free apple is more vulnerable to postharvest disease, which severely limits the cultivation pattern transformation of the apple industry in China. This study aimed to ascertain the dominant pathogens in postharvest bagging-free apples, to evaluate the efficacy of essential oil (EO) on inhibition of fungal growth, and to further clarify the molecular mechanism of this action. By morphological characteristics and rDNA sequence analyses, Botryosphaeria dothidea (B. dothidea) and Colletotrichum gloeosporioides (C. gloeosporioides) were identified as the main pathogens isolated from decayed bagging-free apples. Cinnamon and clove EO exhibited high inhibitory activities against mycelial growth both in vapor and contact phases under in vitro conditions. EO vapor at a concentration of 60 μL L−1 significantly reduced the incidence and lesion diameter of inoculated decay in vivo. Observations using a scanning electron microscope (SEM) and transmission electron microscope (TEM) revealed that EO changed the mycelial morphology and cellular ultrastructure and destroyed the integrity and structure of cell membranes and major organelles. Using RNA sequencing and bioinformatics, it was demonstrated that clove EO treatment impaired the cell membrane integrity and biological function via downregulating the genes involved in the membrane component and transmembrane transport. Simultaneously, a stronger binding affinity of trans-cinnamaldehyde and eugenol with CYP51 was assessed by in silico analysis, attenuating the activity of this ergosterol synthesis enzyme. Moreover, pronounced alternations in the oxidation/reduction reaction and critical materials metabolism of clove EO-treated C. gloeosporioides were also observed from transcriptomic data. Altogether, these findings contributed novel antimicrobial cellular and molecular mechanisms of EO, suggesting its potential use as a natural and useful preservative for controlling postharvest spoilage in bagging-free apples.

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.

IntroductionApricot fruits are edible and serve as a source of medicinal compounds. Flavonols are important plant secondary metabolites that have antioxidant and antitumor effects and may promote cardiovascular health. MethodsThe flavonoid content in three stages of the 'Kuijin' and the 'Katy' was observed, followed by the combination of metabolome and transcriptome analysis to explore the metabolic basis of flavonol synthesis. ResultsThe differences in the metabolite contents between stages (of the same cultivar) and between cultivars (at the same stage) revealed decreases in the flavonoid content as fruits developed (i.e., from 0.28 mg/g to 0.12 mg/g in 'Kuijin' and from 0.23 mg/g to 0.05 mg/g in 'Katy'). To decipher the regulation of flavonol synthesis in apricot (Prunus armeniaca L.), the metabolomes and transcriptomes of fruit pulp at three developmental stages of 'Kuijin' and the 'Katy' were analyzed. A total of 572 metabolites were detected in 'Kuijin' and the 'Katy' pulp, including 111 flavonoids. The higher flavonol content young 'Kuijin' fruits at 42 days after full bloom is mainly due to 10 types of flavonols. Three pairs of significant differences in flavonol content were identified. From these three comparison groups, three structural genes were strongly correlated with the levels of 10 types of flavonols (Pearson correlation coefficients > 0.8, p value < 0.05), including PARG09190, PARG15135, and PARG17939. The weighted gene co-expression network analysis showed that the turquoise module genes were highly correlated with flavonol contents (P < 0.01). There were 4897 genes in this module. Out of 4897 genes, 28 transcription factors are associated with 3 structural genes based on weight value. Two of the transcription factors are not only associated with PARG09190 but also with PARG15135, indicating their critical importance in the flavonols biosynthesis. The two TFs are PARG27864 and PARG10875. DiscussionThese findings provide new insights into the biosynthesis of flavonols and may explain the significant differences in flavonoid content between the 'Kuijin' and the 'Katy' cultivars. Moreover, it will aid in genetic improvement to enhance the nutritional and health value of apricots.

为确定沂源县南鲁山镇'富锶'苹果的果实锶含量及其成因,对南鲁山镇北流水村和璞邱四村苹果园地的水质、土壤、叶片和果实中的锶、锌、硒含量进行了测定与分析.结果 表明,北流水村果园的苹果叶片和果实整个生育期(5-10月)的锶含量(叶片32.4～95.2 mg/kg,果实0.287～1.28 mg/kg)明显高于对照璞邱四村果园(叶片9.87 ～18.4 mg/kg;果实0～0.512 mg/kg),通过对果园水质和土壤的锶、锌、硒含量的检测,推测认为北流水村果园的果实的高锶含量和其果园灌溉水的锶含量较高(11.10 mg/L)有关,而果实较高的硒含量与土质中的硒含量较高(0.06 mg/kg)有关.同时发现,北流水村果园的苹果叶片和果实锌含量(最高11.3 mg/kg)也高于同时期的对照璞邱四村果园(最高5.62 mg/kg),推测这可能与锶促进锌离子的吸收有关,同时也证明了富锶果园果实的维生素C和钙的含量高于对照果园,而糖酸含量低于对照果园.

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.

"黄金蜜"是山东省果树研究所和诸城市果树研究所联合育成的极晚熟、大果型、浓香高甜杏优良新品种,具有早熟高产、果实个大、含糖量高、香气浓郁、晚熟耐贮、果仁脆甜、不落果等优良特性,是我国杏多性状聚合育种的重大突破,具有广阔的发展前景.该品种于2015年12月通过山东省农作物品种审定委员会审定,2017年获得国家林业局授予的新品种权保护."黄金蜜"杏特性及栽培技术要点概述如下.

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.

金水杏为自然实生新品种,2014年定为名种.通过多年试栽与生物学观察表明,该品种果实近圆形,果个中大,平均单果重55.8 g,最大85.2 g,果顶平、稍凹,梗洼中深,缝合线明显、较深,两半部略不对称;果皮薄、光滑有光泽,底色黄绿,完全成熟时阳面有红晕,茸毛短少,与果肉不易剥离;果肉桔黄色,致密、细腻,汁液多,可溶性固形物含量15.2％,香气浓郁,风味酸甜可口,品质极佳;果核中大,离核,苦仁,果实生育期56 d左右,在泰安5月中旬成熟,成熟期比金太阳杏早5～7 d,比凯特杏早15 d以上.介绍了金水杏的栽培技术要点.

[目的]探究富士苹果矮砧砧穗组合生长结果表现,为富士苹果矮砧应用提供参考.[方法]以2010年定植的富士苹果矮砧砧穗组合为试材(烟富3/T337、烟富3/M9以及烟富3/M9、M26、M7、SH6、SH18/八棱海棠),2012—2019年连续研究树体发育、枝类组成、果园结构、光照条件、叶片光合生产、早果性、果实品质及产量的差异.[结果]T337、M9自根砧组合树高、冠径最小,果园透光率显著高于其余组合,中短枝比例最高,定植5 a(年)后中短枝比例稳定在75％以上,易成花,早果性最好,T337定植第2年开花株率达89.7％,3年生单株产量2.83 kg·株-1,第5年进入稳产期,单株产量30.52 kg,果实品质优于中间砧组合,T337平均单果质量、去皮硬度、可溶性固形物含量,分别达286.1 g、8.6 kg·cm-2、15.1％;中间砧组合中M9、M26、SH6行间交接率较低,果园透光率高于M7、SH18,定植第9、10年,M7叶片净光合速率显著降低,定植6年后中短枝比例稳定在60％以上,第6年进入稳产期,可溶性固形物含量以M9、SH6矮化中间砧较高,达到15.0％.T337产量最高,10年生达5264.5 kg·666.7 m-2,中间砧组合中M9、SH6、M26丰产性较好.[结论]综合来看,在烟台地区富士苹果嫁接T337自根砧和M9、M26、SH6中间砧,可以结合实践推广应用.

以富士苹果品种为试材,研究了无袋与套袋栽培对苹果病虫害和果实品质的影响.结果表明,烟富3/M26/八棱海棠和天红2号/SH40/八棱海棠叶片病害主要是斑点落叶病和褐斑病,无袋栽培比例高于套袋,套袋烟富3/M26/八棱海棠比例分别为13.8％和6.5％,不套袋分别为14.5％和7.5％;天红2号/SH40/八棱海棠套袋比例分别为14.0％和8.0％,不套袋比例分别为5.3％和9.7％.果实病虫害,烟富3/M26/八棱海棠主要是蝽蟓、果锈、干腐病和轮纹病,套袋比例分别为0.85％、0.45％、0.40％和0.33％,不套袋比例分别为1.32％、0.86％、0.68％和1.02％,无袋比套袋分别高0.47、0.41、0.28和0.69百分点.天红2号/SH40/八棱海棠果实病虫害主要为炭疽、鸟啄、桃小食心虫、蝽蟓、轮纹病和果锈,套袋比例分别为1.28％、0.35％、0.28％、0.25％、0.25％和0.23％,不套袋比例分别为1.70％、0.50％、0.25％、0.40％、0.48％和0.20％;炭疽、鸟啄、蝽蟓和轮纹病不套袋比套袋分别高0.42、0.15、0.15和0.23百分点,而桃小食心虫和果锈比例无袋比套袋均低0.03百分点.套袋苹果着色指数和光洁度指数明显高于不套袋,而单果重和硬度不套袋明显高于套袋,果形指数、可溶性糖和可溶性固形物含量差异不显著,可滴定酸含量套袋高于不套袋,糖酸比不套袋高于套袋.

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.

黄金蜜是山东省果树研究所和诸城市果树研究所联合育成的极晚熟、大果型、浓香高甜杏优良新品种,具有早实高产、果个大、含糖量高、香气浓郁、晚熟耐贮、果仁脆甜、不落果等优良特性.介绍了黄金蜜杏的生物学特性和栽培技术要点.

Light and low temperatures induce anthocyanin accumulation, but intense sunlight causes photooxidative sunburn. Nonetheless, there have been few studies of anthocyanin synthesis under different sunlight intensities and low nighttime temperatures. Here, low nighttime temperatures followed by low light intensity were associated with greater anthocyanin accumulation and the expression of anthocyanin biosynthesis genes in “Fuji” apple peel. UDP-glucose flavonoid-3-O-glucosyltransferase (UFGT) activity was positively associated with anthocyanin enrichment. Ascorbic acid can be used as an electron donor of APX to scavenge H2O2 in plants, which makes it play an important role in oxidative defense. Exogenous ascorbate altered the anthocyanin accumulation and reduced the occurrence of high light–induced photooxidative sunburn by removing hydrogen peroxide from the peel. Overall, low light intensity was beneficial for the accumulation of anthocyanin and did not cause photooxidative sunburn, whereas natural light had the opposite effect on the apple peel at low nighttime temperatures. This study provides an insight into the mechanisms by which low temperatures induce apple coloration and high light intensity causes photooxidative sunburn.

[目的]苹果免套袋栽培是我国苹果产业发展的必然趋势,而在此模式下,苹果的病虫害发生较为严重.探究免套袋苹果采后真菌的发病情况以及精油对其抑菌效果,为免套袋苹果病虫害的绿色防控奠定基础.[方法]分别调查山东苹果主产区的免套袋、套袋2种栽培模式下苹果的采后发病情况;采用传统形态鉴定结合ITS序列比对对免套袋苹果致病真菌进行了分类统计及种属鉴定;熏蒸处理评价了肉桂精油对致病菌的离体抑菌效果,并通过电子显微镜分析了其抑菌机制.[结果]免套袋苹果的采后发病率显著高于套袋苹果(p＜0.05),免套袋苹果果实上共分离鉴定出6种病原真菌,分别为葡萄座腔菌(Botryosphaeria dothidea)、链格孢属(Alternaria)、粉红单端孢菌(Trichothecium roseum)、韦司梅拟盘多毛孢菌(Pestalotiopsis vismiae)、胶孢炭疽菌(Colletotrichum gloeosporioides)及产核枝顶孢菌(Acremoni-um sclerotigenum).80 μL?L-1的肉桂精油对以上6种真菌的抑菌率均超过80％.精油对苹果的活体防治试验表明,80 μL·L-1肉桂精油可显著降低苹果果实的发病率(p＜0.05).经显微镜分析可知,精油抑制了孢子萌发,改变了病原菌的正常菌丝形态.[结论]肉桂精油作为免袋栽培苹果采后防腐抑菌剂有较好的应用前景.

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。

为明确苯嗪草酮疏果剂对苹果边果的疏除作用,以9年生天红2号/SH38/八棱海棠为试材,在最大边果直径6 mm左右时喷300 mg/kg苯嗪草酮2次,清水为对照,生理落果后调查坐果率及坐果比例;喷药后7、9、11、17、29 d采集处理和对照边果,测定氮磷钾矿质营养,淀粉、葡萄糖、果糖、蔗糖和山梨醇碳水化合物,可溶性蛋白质含量以及玉米素(Z)、赤霉素(GA3)、生长素(IAA)和脱落酸(ABA)激素含量.结果显示,苯嗪草酮处理后,花序坐果率和花朵坐果率较对照降低17.95％和27.63％,坐单果比例显著提高,坐三果及三果以上的比例显著降低(P<0.01);处理总体上提高了边果无机营养含量,显著降低了可溶性蛋白质含量(P<0.05);淀粉含量较对照提高了5.57％～37.20％,但不同程度地降低了蔗糖、葡糖糖、果糖及山梨醇含量,从而使可溶性碳水化合物含量较对照降低了9.55％～52.60％;处理后脱落酸含量显著升高(P<0.05),(Z+GA3+IAA)/ABA比值显著降低.说明苯嗪草酮在苹果上具有较好的疏除边果作用,其疏除作用与可溶性蛋白质含量降低,可溶性碳水化合物供应不足,以及ABA含量升高及生长型激素/抑制型激素比值降低有关.

苹果免套袋栽培可显著降低生产成本,提高果实内在品质,是当前苹果节本增效栽培的研究热点.总结了苹果免套袋栽培优质生产技术,涵盖了品种选择、园相指标、树形结构、土肥水管理等方面,以期为苹果免套袋栽培提供参考依据.

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.