【Objective】Apple is the most widely cultivated deciduous fruit species in China, possessing considerable adaptability and economic value. Since the reform and opening-up, the apple industry has developed rapidly. However, the homogenized variety structure and its monotonous flavour profile can no longer meet consumers'growing demand for greater diversity in fruit. The cultivation of diverse, differentiated and personalized new apple varieties holds significant importance, with the development of small-fruit type apples emerging as one of the new breeding objectives. Therefore, we systemically investigated fruit quality traits of characteristic small-fruit type apple germplasm resources and conducted a comprehensive evaluation, thereby providing valuable reference and a theoretical basis for the innovative utilization of superior germplasm resources.【Methods】This study utilized 5 characteristic smallfruit type apple cultivars, namely Huangtaiping, Jinhong, Hesetiaowen, Whitney, and Xinhong, as exper-imental materials to measure and analyze their fruit morphological characteristics and quality trait indicators. Apple fruit phenotypic traits were surveyed and recorded in accordance with the‘Apple Germplasm Resource Description Specifications and Data Standards'. The determination of soluble sugars and organic acids in apples was carried out using high-performance liquid chromatography. The determination of polyphenolic components and their contents was performed using ultra-high-performance liquid chromatography-mass spectrometry. Five fruit sections including cross sectional, longitudinal sectional, cheeks, stem cavity and calyx-end were selected. After 24-hour fixation at room temperature to ensure complete penetration of the fixative, paraffin sections were prepared. Cytological observations were conducted on five-part fruit sections of apple varieties using paraffin sections. Finally, a comprehensive evaluation of fruit quality traits across different varieties was performed through correlation analysis and fuzzy membership function methods.【Results】Five characteristic small-fruit type apple varieties exhibit significant differences in fruit morphological characteristics and quality indicators. The fruit color of Huangtaiping and Hesetiaowen is pink, while Jinhong, Whitney and Xinhong are turkey red, brown red, and strong red, respectively. The fruit surfaces of Jinhong and Xinhong show arris, while other apple varieties have no arris. The fruit dots of Huangtaiping and Hesetiaowen varieties exhibit small dots, while Whitney and Xinhong display large dots. The fruit cores of Jinhong and Xinhong are small, while the cores of Huangtaiping, Hesetiaowen, and Whitney are medium. In terms of fruit morphological characteristics, the stem depression of Jinhong fruit is shallow and narrow, while Huangtaiping, Whitney and Xinhong are all deep and medium. Additionally, the range of fruit weight across different apple varieties is 42.03-82.55 g. Among these, Huangtaiping apples exhibit the lowest fruit weight, and both the transverse and longitudinal diameters of Huangtaiping apples are significantly smaller than those of other apple varieties. However, the titratable acidity, malic acid, citric acid, flavanols, phenolic acids, and total phenolic contents of Huangtaiping fruit are significantly higher than those of other apple varieties. Xinhong fruit exhibit the highest levels of fructose and sorbitol. Hesetiaowen fruit contain the highest levels of soluble solids, soluble sugars, sugar-acid ratio, sucrose, and dihydrochalcone. The Whitney apple variety exhibits the highest levels of glucose and flavonoids among all apple varieties, with a significantly higher content of phlorizine compared to other apple cultivars. Significant differences in cell morphology, size, and number also exist among different apple varieties. The fruit cells of Huangtaiping and Jinhong are arranged relatively densely, and exhibit consistent morphology across different parts. The fruit cells of Hesetiaowen are arranged in a relatively loose pattern. The cross section and longitudinal section of Whitney fruit show relatively dispersed cells with distinct intercellular spaces. The cell boundaries of Xinhong fruit exhibit an irregular shape. In terms of cell size and number in different fruit parts, the cross-sectional cell size and longitudinal cell number of Huangtaiping are significantly lower than those of other apple varieties, while there is no significant difference in cross-sectional cell size and longitudinal cell size, indicating that the volume difference between Huangtaiping fruit and other apple varieties mainly depends on the cross-sectional cell size and longitudinal cell number. There are significant differences in the number and size of cells in the stem cavity and calyx-end of various apple varieties, except for the number of cells in the cheeks. Significant differences exist in fruit size among varieties, with both the number of fruit cells and the volume of the fruit jointly influencing the final size of the fruit.【Conclusion】The comprehensive evaluation results based on the fuzzy membership function method indicate that the Hesetiaowen fruit exhibits the highest average membership function value, followed by the Huangtaiping, Whitney, Xinhong, and Jinhong fruits in a descending order. The evaluation results are consistent with the growth status and phenotypic characteristics of each apple germplasm resource. Based on the quality characteristics of each germplasm, specific traits such as high-quality fresh type, distinctive appearance type, and functional/processing type can be selected for germplasm breeding. The above research provides important references for the screening and comprehensive utilization of characteristic small-fruit type apple germplasm resources.

Polyphenols are recognized as a class of compounds possessing a wide range of biological activities that provide numerous health benefits to humans. Apples are abundant in polyphenolic substances. As an integral part of the fruit's internal structure, the polyphenols found in fruit cores cannot be overlooked. This study examines the dynamic effects of six different dwarfing interstocks on the total phenolic content and polyphenol compounds in the core of 'Huahong' apples, aiming to gain a more comprehensive understanding of the phenolic components and their contents in fruit cores, providing novel insights into the comprehensive utilization of fruits. The 'CG24', 'SH38', 'SH3', 'MD001', 'Mac9', and 'CX5' were grafted onto Malus baccata (L.) Borkh. and 'Huahong' was grafted on six interstocks mentioned above, the self-root grafting Malus was used as a control (CK). The components and contents of polyphenols in cores were analyzed at seven periods during 'Huahong' apple growth by using High Efficiency Liquid Chromatography and Mass Spectrometry, and the content of total phenols was determined by the Folin-Ciocalteu method. The polyphenol concentration in the fruit core exceeds that of the peel but is lower than that found in the pulp, and this content, along with its constituent components, exhibits a gradual decline as the fruit undergoes development. At maturity, the polyphenol composition is consistent across dwarfing interstock combinations, primarily comprising Quercetindevelopment, but these levels drop below the control group in later stages. In contrast, 'MD001' effectively mitigates the reduction of polyphenols from mid- to late development, leading to substantial phenolic accumulation at maturity. Among the interstocks examined, 'MD001' demonstrates its superiority in enhancing phenolic compounds. Interstocks can increase the levels of polyphenolic compounds in the core of apples. The polyphenol content in the fruit core is intermediate between that of peel and flesh, exhibiting significant application value in processing and the extraction of polyphenol components.

To investigate chilling injury mitigation in off-season solanaceousvegetable production, this study conducted physiological and multi-omics analyses on six rootstock cultivars-'Totosga' (TTS), 'Jingfeng 808 ' (JF), 'Torubam' (TLB), 'Qiangli' (QL), 'Jinzuan No.1 ' (JZ), and 'Weiershengen' (WS)-under low-temperature stress. Among these, the cold-tolerant genotype 'Totosga' exhibited superior photosynthetic integrity, membrane stability, and antioxidant enzyme activity. Comparative transcriptomic and metabolomic profiling identified 2517 differentially expressed genes (1015 upregulated; 1502 downregulated) and 2728 differential metabolites (1465 increased; 1263 decreased) under cold stress. Transcriptomic alterations predominantly affected photosynthesisrelated pathways and calcium-mediated signal transduction, whereas metabolomic changes were concentrated in secondary metabolic processes. Integrative omics analysis revealed significant enrichment in flavonoid biosynthesis, identifying eight hub genes (e.g., PAL2, CHS2, FLS) and 16 key metabolites (e.g., isoliquiritigenin, calycosin) as regulatory components. Mechanistic investigations demonstrated that 'Totosga' enhances cold adaptation through coordinated flavonoid metabolic reprogramming, characterized by (1) flavanol biosynthesis suppression, (2) isoflavonoid pathway activation, and (3) glycosylation/hydroxylation modifications for metabolite stabilization. Therefore, these findings elucidate the molecular basis of rootstock cold adaptation and provide valuable genetic resources for developing stress-resilient solanaceous cultivars.

IntroductionHydrogen-rich water (HRW) plays a crucial role in regulating plant growth and development. However, its potential involvement in modulating photosynthetic pigments, chlorophyll fluorescence (ChlF) parameters, antioxidant enzyme activities, and fruit ripening in (Vitis vinifera L.) ‘Flame Seedless’ grapes grown in a greenhouse remain unclear.MethodsThis study aimed to investigate the effects of HRW irrigation at a concentration of 1.0 mg L-1 on chlorophyll pigments, ChlF parameters, enzymatic antioxidant activities, and fruit quality.ResultsHRW irrigation induced a significant increase in carotenoid (Car) content, which was observed only on the first day after irrigation. It also significantly enhanced chlorophyll a (Chl a) and chlorophyll b (Chl b) contents, as well as ChlF parameters such as maximum quantum efficiency of photosystem II (Fv/Fm), and the photochemical quantum yield of PSII (ΦPSII), while non-photochemical quenching (NPQ) decreased, indicating enhanced PSII functionality and photosynthetic performance. Antioxidant enzyme activities, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), were also enhanced, reducing reactive oxygen species (ROS) accumulation and maintaining ROS homeostasis in grapevine leaves. HRW treatment promoted the accumulation of secondary metabolites such as total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (TAC), and Car, which contributed to an improved color index of red grapes (CIRG). Additionally, fruit quality was improved by increasing total soluble solids (TSS), soluble sugars, and pH, while reducing fruit firmness and titratable acidity (TA). Berry weight and overall yield were also enhanced compared with control plants.DiscussionThese results demonstrate that HRW is a promising and sustainable approach for enhancing photosynthetic performance, antioxidant defense, secondary metabolite accumulation, and fruit quality in greenhouse-grown ‘Flame Seedless’ grapes, providing a practical basis for improving grape cultivation and production.

MicroRNAs are non-coding RNAs that play a crucial regulatory role in plant growth, development, and environmental stress response. 'Binzi' is an ancient apple cultivar renowned for its unique aroma, however, the mechanisms of miRNAs underlying aroma formation remain largely unknown. In this study, we performed small RNA sequencing to investigate the role of miRNAs during post-harvest storage of 'Binzi' apple. Peel samples from 'Binzi' fruit (namely BZP01 and BZP02) at two storage stages (20 +/- 1 degrees C) were sequenced. A total of 29 DEMs (15 miRNAs uniquely detected at specific storage periods and 14 miRNAs differentially expressed in different storage periods) were predicted to regulate aroma compound biosynthesis in 'Binzi' apple peels. A total of 604 genes were predicted to be targeted by 29 miRNAs. GO enrichment analysis was performed on the target genes, with 'cellular process', 'metabolic process', 'single-organism process', and 'catalytic activity' being the over-enriched biological processes. KEGG analysis showed that three pathways related to aroma synthesis ('fatty acid metabolism', 'biosynthesis of unsaturated fatty acid biosynthesis', and 'carotenoid biosynthesis') were enriched in the top 20 of the KEGG enrichment. We verified the regulatory relationship between miRNAs and their target genes by qRT-PCR. mdm-miR408c was negatively correlated with three target genes (two MdfabDs and one MdfabG) and was involved in the regulation of fatty acids biosynthesis. Furthermore, novel_Chr17_18081 was negatively correlated with MdMFP2 and was involved in the regulation of the fatty acid degradation. Our research indicated that mdm-miR408c, novel_Chr17_18081, and their target genes (MdfabDs, MdfabG, and MdMFP2) were collectively involved in 'Binzi' aroma production.

Folate-mediated one-carbon metabolism (FOCM) is closely associated with postharvest preservation. This study investigated the effects of exogenous nitric oxide (NO) on FOCM, storage quality, energy metabolism, and mitochondrial membrane integrity in cold-storage peach fruit. In this experiment, peaches were soaked with 1.5 mmol L −1 S -nitrosoglutathione (GSNO) as NO donor, and the negative treatment (NT) solution containing 5 μmol L −1 carboxy-PTIO (c-PTIO, NO scavenger), 200 μmol L −1 N G -Nitro- L -arginine methyl ester ( L -NAME, NO synthase-like enzyme inhibitor), and 200 μmol L −1 sodium tungstate dihydrate (nitrate reductase inhibitor) and stored at 0°C. The results showed that NO decreased the activity of S -adenosylmethionine synthase and S -adenosylhomocysteine hydrolase and increased the activity of methionine sulfoxide reductase A, as well as the content of N5-methyl-THF, the ratio of tetrahydrofolate (THF), homocysteine, methionine, S -adenosylmethionine (SAM), and SAM to S -adenosylhomocysteine compared with the control, indicating that NO effectively increased FOCM flux by affecting the activity of FOCM enzymes. Meanwhile, NO increased the activities of H + -ATPase, Ca 2+ -ATPase, cytochrome c oxidase, succinate dehydrogenase, and the contents of adenosine triphosphate and adenosine diphosphate, and maintained high energy charge in peaches during storage. NO retarded the increase in mitochondrial permeability transition, reactive oxygen species content, and the decrease in mitochondrial membrane fluidity, membrane potential, and swelling. NT treatment exhibited the opposite results. In conclusion, these results suggested that NO could induce the accumulation of folate and FOCM flux and maintain mitochondrial energy levels, which might be responsible for maintaining the quality of peaches during cold storage.

Low temperature can affect DNA methylation. Since exogenous use of NO can reduce cold damage in peach fruit during cold storage, this study investigated the roles of NO on DNA methylation of peaches suffering cold stress. The results showed that exogenous NO effectively alleviated the decrease in total DNA methyltransferase (DNMT) activity and transcript levels induced by cold stress, whereas c-PTIO exacerbated the decrease in total DNMT activity and transcript levels. Further BSP analysis of the promoter regions of four cold resistance genes (PpCBF5-IS2, PpICE1-IS, PpMYC2-IS, PpCOR-IS1) in peaches showed that in peaches treated with exogenous NO, PpCBF5-IS2 and PpICE1-IS were modified by hypermethylation, PpMYC2-IS was modified by methylation, PpCOR-IS1 was modified by demethylation and insensitive to NO. It was suggested that NO could enhance the cold resistance of postharvest peaches by mediating DNA methylation.

Mitochondrial transcription termination factors (mTERFs) are involved in the replication, transcription, and translation of mitochondrial genes and have essential biological functions in plant development and stress response. However, the functions and regulatory mechanisms of many mTERF family members are still unclear. In this study, the cDNA coding region sequence of the mitochondrial transcription termination factor 18 (mTERF18) gene in peaches was cloned, the peaches mTERF18 protein was predicted and analyzed, and the gene was conducted transient transformation in tomato and peach to investigate the roles of PpmTERF18 in fruit mitochondrial function and antioxidant capacity. The results showed that the PpmTERF18 gene encoded 573 amino acids, mainly composed of alpha-helix and beta-sheet, an alkaline-labile protein in mitochondria. The results showed that overexpression of PpmTERF18 in tomatoes delayed the color change, and overexpression of PpmTERF18 in peach fruit could maintain the quality of peach fruit. Overexpression of PpmTERF18 increased the activities and the expression levels of mitochondrial antioxidant-related genes, reduced mitochondrial oxygen consumption and cytochrome c content, inhibited the opening of mitochondrial permeability transition pore (MPTP), and maintained mitochondrial functions in tomato and peach fruit. After cold stress treatment, overexpression of PpmTERF18 increased the proline content and phenylalanine ammonia-lyase (PAL) activity in peach fruit, decreased the content of malondialdehyde (MDA), improved the antioxidant capacity of the fruit, and maintained the quality of the fruit.

Apple (Malus domestica) is an important multi-functional horticultural crop. However, thus far, there have been few reports concerning the molecular mechanism by which interstock regulates rootstock and scion growth. MicroRNAs (miRNAs) are a type of post-transcriptional regulator that regulates apple growth and development, fruit quality, hormone signal transduction, and stress response. Interstock grafting resulted in differences in miRNA distribution between apple tissues. The regulatory roles of miRNAs in the grafting of apples are not yet clear. In this study, 15 libraries were constructed using the phloem of an apple grafted on two types of interstock and rootstock by high-throughput sequencing. A total of 281 miRNAs were catalogued into 80 families, and 159 novel ones were identified. Compared with the control, the grafting combination with the interstock resulted in 79 differentially expressed miRNAs (DEMs) in the scion, with 36 up-regulated and 43 down-regulated miRNAs, and 57 DEMs in the rootstock, including 22 up-regulated and 35 down-regulated miRNAs. Grafting with the dwarfing interstock led to DEMs in the whole plant, including a decrease in the expression of mdm-miR156 in the scion and mdm-miR172 in the rootstock. Predictive analysis of the DEMs and their target genes suggested that miRNAs mediate scion growth through several aspects, such as plant hormone synthesis and signal transduction, and nutrient absorption and balance. Through combined miRNA and mRNA analysis, the dwarfing effect of the interstock may affect the expression of genes related to the starch and sucrose metabolism pathways in the rootstock and the plant hormone signal transduction pathway in the scion. The available evidence facilitates a better understanding of the role of miRNAs in the response of apples after grafting interstock. One possible reason for the stunting of apple trees and the promotion of early flowering caused by the dwarfing interstock is the decrease in expression levels of mdm-miR156 and mdm-miR172.

Apples are a major horticultural crop worldwide. Grafting techniques are widely utilized in apple production to keep the varieties pure. Interstocks are frequently used in Northern China to achieve intensive apple dwarfing cultivation. High-throughput sequencing was used to investigate differentially expressed genes in the phloem tissues of two different xenograft systems, M (‘Gala’/‘Mac 9’/Malus baccata (L.) Borkh.) and B (‘Gala’/Malus baccata (L.) Borkh.). The results showed that dwarfing interstocks could significantly reduce the height and diameters of apple trees while have few effects on the growth of annual branches. The interstocks were found to regulate the expression of genes related to hormone metabolism and tree body control (GH3.9, PIN1, CKI1, ARP1, GA2ox1 and GA20ox1), these effects may attribute the dwarf characters for apple trees with interstocks. Besides, the interstocks reduce photosynthesis-related genes (MADH-ME4 and GAPC), promote carbon (C) metabolism gene expression (AATP1, GDH and PFK3), promote the expression of nitrogen (N)-metabolism-related genes (NRT2.7, NADH and GDH) in rootstocks, and improve the expression of genes related to secondary metabolism in scions (DX5, FPS1, TPS21 and SRG1). We also concluded that the interstocks acquired early blooming traits due to promotion of the expression of flowering genes in the scion (MOF1, FTIP7, AGL12 and AGL24). This study is a valuable resource regarding the molecular mechanisms of dwarf interstocks’ influence on various biological processes and transplantation systems in both scions and rootstocks.

【Objective】 This study aims to establish an accurate and non-destructive model for apple leaf area estimation.【Methods】 Leaves were collect from vegetative and bourse shoots considering their length for Fuji and Gala apple trees.Leaf morphological parameters, such as leaf length（LL）, leaf width（LW） and leaf area（LA）, were obtained by digital scanner.17 candidate models with or without constant were evaluated by determination coefficient（R~2）, root mean square error（RMSE） and Akakchi Information Criterion（AIC）.【Results】 Leaf morphological characteristics of 5,207 leaves were obtained, and among those leaf are had the highest coefficient of variation by 51.59%.Leaf morphologies were significantly affected by shoot types and cultivars The LL, LW and LA of long shoots were significantly larger than those of short shoot, and those were significantly higher in vegetative shoot than bourse shoot when the shoots belong to same category determined by shoot length.Leaves in Gala were more slender than those in Fuji.The accuracies of following selected models where LL and LW were used as independent variables can meet the requirements for leaf area estimation in apple trees, including model 5: LA = a（LL×LW）, model 6: LA = a（LL+LW）~2, model 9: LA = aLL~2+bLW~2, model 16: LA = a（LL×LW） b , and model 17: LA =（LL×LW） b ., but model need to be established for each shoot type and cultivar.Those models had both LL and LW variables were more reliable than those models only had LL or LW solely.Among shoot types, regarding the accuracy of selected models, bourse was the highest, short shoot was higher than that of long shoot, and vegetative long shoot was the lowest.The all-data model 5（R~2= 97.72%, RMSE = 1.756,6 cm~2） and 17（R~2= 97.37%, RMSE =1.831,9 cm~2） were available to estimate the leaf area no matter of cultivars or shoot types with same model coefficients.The accuracies of the models 5 and 17 were not improved by adding constant.The model coefficients for model 5 and 17 were 0.712,3 and 0.910,8, respectively.The minimum number of samples was 241 and 3,939 for model 7 and 17, respectively; to have relative errors lower than 5%.【Conclusion】 The selected models in current study can be used for leaf area estimation irrespective of cultivars and shoot types, without the need of establishing model for each type of shoot and cultivar.The addition constant had no effect on selected model accuracy, and there is a minimum number of samples for model were required to have lower relative error.

【Objective】Apple cultivars have been classed into Fuji-strain, Delicious-strain, Golden Delicious-strain and Ralls-strain according to their parents in China. In this study, the fruit aroma characteristics of different strains were analyzed, so as to provide the reference for studying fruit quality and aroma breeding.【Method】Solid-phase microextraction and gas chromatography-mass spectrometry (SPME-GC-MS) were used to detect the fruit aroma components and their content of 50 apple cultivars belonging to 4 strains. Coefficient of variation (CV) and principal component analysis (PCA) were used to compare the significance and characteristics of aroma substances among the different strains.【Result】A total of 146 aroma components were detected from 50 cultivars. Esters (38), aldehydes (29) and alcohols (19) played a dominant role in all aroma components, which accounted for 72.82% of the total content. CV of esters was the highest in number and content of three ruling aroma components. The number of total aroma components of Fuji-strain and Delicious-strain were significantly more than that of other strains (P<0.05). The number of Fuji-strains and Delicious-strains were meaningfully more than that of Golden Delicious-strain and Ralls-strain (P<0.05). However, the number of aldehydes and alcohols did not show a significant level among the different strains. 28 characteristic aroma components were identified from 146 aroma components according to the criterion of aroma value greater than 1, eight components of which were detected in more than 40 cultivars, and they were defined as typical aroma components of apple. The eight principal components (PCs) were extracted from 28 characteristic aromas by PCA. 50 cultivars were scattered to four regions, which represented different flavor types. According to the smell characteristics of aroma components, Fuji-strain and Delicious-strain were distributed in four regions; Golden Delicious-strain and Ralls-strain were mainly distributed in green and light flavor regions, respectively; Rich fragrance regions were primarily Delicious-strain, and sweet fragrance region were mainly Fuji-strain. Different breeding methods had stronger effects on Golden Delicious-strain and Ralls-strain, as the similarity coefficient and the proportions of aroma components shared with the controls in the hybrid cultivars were significantly lower than those of the bud sport cultivars (P<0.05). In all the strains, the number of transgressive phenomena in the bud sport cultivars was more than that in the hybrid cultivars.【Conclusion】The fruit flavor of Golden Delicious-strain and Ralls-strain was more abundant. Fuji-strain, Delicious-strain, Golden Delicious-strain and Ralls-strain could be classed as sweet fragrance type, rich fragrance type, green fragrance type and light fragrance type, respectively. Hybridization could increase the content of aroma components and increase the complexity of aroma composition. Bud sport breeding had less effect on aroma composition, but more effect on aroma content to the progenies, and the transgressive phenomena was more obvious than that of hybridization breeding.

Hydrogen sulfide (H2S), which is a gasotransmitter, can be biosynthesized and participates in various physiological and biochemical processes in plants. H2S also positively affects plants' adaptation to abiotic stresses. Here, we summarize the specific ways in which H2S is endogenously synthesized and metabolized in plants, along with the agents and methods used for H2S research, and outline the progress of research on the regulation of H2S on plant metabolism and morphogenesis, abiotic stress tolerance, and the series of different post-translational modifications (PTMs) in which H2S is involved, to provide a reference for future research on the mechanism of H2S action.

Low-temperature storage is convenient for postharvest preservation of peach fruit, but peach fruit is sensitive to cold damage, which lowers its quality. Nitric oxide (NO) has the potential to improve the bitter resistance of peach fruit. In this work, peach fruit was treated with 15 mu mol L-1 NO and 5 mu mol L-1 c-PTIO [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxo-3-oxide], to study changes in mitochondrial fatty acids and expression of the C-repeat binding factor (CBF). The results showed that 15 mu mol L-1 exogenous NO significantly maintained fruit quality, reduced peroxidation of mitochondrial fatty acids, increased the activities of the antioxidants superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbic acid peroxidase (APX), and reduced the content of hydrogen peroxide (H2O2). Meanwhile, NO treatment suppressed the increase in browning index and ion leakage rate, increased the activity of S-nitrosoglutathione reductase (GSNOR), the contents of S-nitrosothiols (SNOs), and the ratios of mitochondrial NAD+/NADH and NADP+/NADPH, increased the expression levels of PpCBF1/5/6. However, the expression levels of PpCBF2/3/4 were not significantly regulated by exogenous NO. Peaches treated with c-PTIO showed opposite effects to those treated with exogenous NO. These results suggest that exogenous NO can improve antioxidant capacity, preserve mitochondrial fatty acids, and upregulate the expression of PpCBF1/5/6 to alleviate cold tolerance and maintain the peach quality during storage.

‘Huahong’ is a popular apple cultivar because of its anti-browning properties and appealing aroma and flavor. It is mainly planted by grafting on dwarf interstocks in Northeast China. We investigated the different aroma profiles of apple fruits grown from six dwarf interstocks (‘CG24’, ‘SH38’, ‘SH3’, ‘MD001’, ‘Mac9’, and ‘CX5’) and from no interstocks (CK). A total of 55 VOCs were detected, including esters (25), aldehydes (14), alcohols (8), ketones (3), alkane hydroxyls (3), and acids (2). Among the VOCs, 48 were detected in the skin and 21 in the pulp. The skin of ‘Huahong’ apples had a strong sweet aroma, and the pulp was green with a subtle aroma. The dominant compounds (>5% of total content) in the skin were 2-methyl butyl acetate, hexyl 2-methyl butyrate, caproic acid butyl ester, hexanal, (Z)-2-heptene aldehyde, and 6-methyl-5-heptene-2-ketone, while in the pulp, they were 2-methyl butyl acetate, methanol, 2-methyl-1-butanol, hexanol, and hexane. Compared with CK, ‘SH38’, ‘MD001’, and ‘SH3’ interstocks had increased total aroma content, and ‘CX5’ and ‘CG24’ had suppressed aroma. The effects of interstocks on aroma were mainly reflected in skin. The VOC content ranged from 3297.52 to 9895.75 µg·kg−1 in skin, and from 748.62 to 1369.21 µg·kg−1 in pulp. PCA revealed that use of interstock ‘SH38’ mainly affected esters. ‘MD001’ affected hexane and 4-pentene-1-acetate; ‘Mac9’ and ‘SH3’ affected octanoic acid-2-methyl butyl ester, hexyl butyrate, and 2-methyl-1-butanol; and ‘CX5’ and ‘CG24’ had a greater impact on isoamyl propionate and 1-pentene-3-ol. Finally, ‘SH38’ had the highest principal comprehensive score. ‘SH38’ and ‘SH3’ interstocks resulted in significantly increased apple VOC content.

[目的]探讨6个不同矮化中间砧对华红苹果果实中总酚及组分动态含量的影响,为苹果矮化中间砧的选择应用和优质苹果生产提供应用依据.[方法]以山荆子为基砧,CG24、MD001、SH3、SH38、Mac9和CX5为中间砧,嫁接华红为试验材料,山荆子直接嫁接华红为对照;在果实生长发育的7个时期,采用超高效液相色谱法及质谱联用技术测定多酚组分及含量、Folin-Ciocalteus法测定总酚含量.[结果]华红果皮中总酚含量在所有时期均高于果肉,且随着果实的发育逐渐降低,但在发育过程中出现最小值的时期不同:果肉在成熟期最低,果皮8月29日最低;果皮、果肉多酚组分含量随着果实发育和成熟逐渐降低或在果实发育阶段先降低,随着果实成熟增高,不同矮化中间砧组合对果皮、果肉多酚组分的动态变化有不同程度的影响.在成熟期,SH38组合、CG24组合和SH3组合提高了华红果皮总酚含量,MD001组合和SH38组合提高了华红果肉总酚含量;Mac9组合和SH38组合显著提高华红花青苷含量,进而促进果实着色;SH38组合和MD001组合对果皮、果肉多酚组分的含量提升较多.[结论]SH38组合可考虑作为提高华红苹果功能性栽培的首选中间砧.

Apple rootstock seedling M.9-T337 was selected to explore the effect of drought stress. The findings indicated that the relative water content of both the leaf and soil gradually decreased with an increase in drought stress. The water-use efficiency of the leaves increased gradually but decreased sharply after 20 d of drought. Changes in the gas-exchange parameters and chlorophyll fluorescence parameters reflected the gradual decrease in the photosynthetic capacity of the plants with drought stress duration. Infrared thermal imaging showed significant temperature differences between the drought-stressed and control plants after 15 d of drought treatment. When irreversible damage occurred under drought stress, the crop water-stress index and relative water content of the leaf and soil were 0.7, 60.5, and 17.8%, respectively. Based on the results, we formulated a drought stress-grade standard. Further, we established that the best time for irrigation is when drought stress reaches grade 3.

[目的]研究黄腐酸在葡萄上应用效果及最佳施用量,为黄腐酸肥在郑艳无核葡萄上合理应用提供理论参考.[方法]以4年生的郑艳无核葡萄为试材,黄腐酸施用量分别为0、2.5、5、11、33和100 g/株,分别于葡萄开花期、幼果期、着色期和果实膨大期根际施入.[结果]与未施黄腐酸的处理相比,施黄腐酸可显著提高土壤的有机质、硝态氮、铵态氮、速效磷、速效钾含量;提高葡萄的L*值、色泽指数、糖酸比、VC含量、提高果实硬度和葡萄产量.6种施黄腐酸处理中以施33 g/株(0.33 g/L)黄腐酸对提高土壤养分、葡萄果实品质、葡萄产量的效果最为显著.[结论]施用黄腐酸肥能明显提高土壤养分,提高葡萄品质,增加葡萄产量.33 g/株(0.33 g/L)为黄腐酸推荐用量.

为了阐明矮化砧木调控苹果叶片光合作用对光照度和CO2响应的机制,筛选适宜的苹果叶片光合模型,以8a生'长富2号'苹果为试材,设置4种砧木处理.M9、M26、M9/八棱海棠和M26/八棱海棠.结果 表明:各个模型均可用于模拟不同砧木苹果叶片光合—光响应(Pn-PAR)和光合—二氧化碳(Pn-CO2)响应过程,决定系数(R2)均大于0.99.非直角双曲线模型(NRH)对M9/八棱海棠和M26/八棱海棠叶片的Pn-PAR曲线模拟的R2最大,均方根误差(RMSE)和平均绝对误差(MAE)最小,直角双曲线修正模型(MRH)对M9和M26叶片的Pn-PAR曲线模拟的R2最大,RMSE和MAE最小,且MRH模型对各处理的Pn-CO2曲线模拟精度最高.与实测值相比,基于MRH模型的光合参数估计值相对误差最小,且获得的参数信息最全面,NRH模型次之.M26和M26/八棱海棠的初始量子效率、最大净光合速率、光饱和点、羧化效率、光呼吸速率高于M9和M9/八棱海棠,而光补偿点、CO2补偿点、暗呼吸速率低于M9和M9/八棱海棠,说明M26对弱光和低CO2浓度的利用效率高,耐弱光能力强,呼吸消耗少.结论:基于叶片尺度光合模型的砧木光合能力评价可优先考虑使用NRH和MRH模型.M26在作为基砧及中间砧的叶片光合能力优于M9.

为探究黄腐酸对阳光玫瑰葡萄果实品质及产量的影响效果.本文研究以4年生的阳光玫瑰葡萄为试材,设置6个黄腐酸肥施用量(0、2.5、5、11、33、100 g/株),分别于开花期、幼果期、转色期、果实膨大期根际施入,对不同用量黄腐酸肥处理下的叶片养分、叶绿素含量、净光合速率、产量、果实品质及香气物质含量进行测定与分析.结果表明:与对照T0相比,施用黄腐酸处理叶片的氮、磷、钾含量均显著提高,但超过一定浓度后叶片氮、磷含量出现下降(T5处理),葡萄叶片叶绿素相对含量和净光合速率也显著提高,其中T3和T4处理葡萄的单株产量分别达到10.17 kg和10.57 kg,且葡萄果实可滴定酸含量较其它处理最低,可溶性固形物和维生素C含量间无显著差异,但显著高于其它处理;对照中未检测到松油醇、橙花醇和柠檬烯,T3和T4处理检测到的萜类香气物质种类最多,而且每种香气物质的含量比其他处理都高;本文试验条件下11～33 g/株为黄腐酸肥推荐用量,可为阳光玫瑰葡萄的优质高产提供参考.