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Abstract The ecological benefits and concerns surrounding fossil fuels had led to increased interest in bio-based rigid polyurethane foam (RPUF). Nonetheless, due to its flammability, it had limited application in various fields. To solve this problem, a green bio-flame retardant, cobalt hydroxystannate (CoSn(OH)6), was prepared and compounded with montmorillonite (MMT) and chick feather protein (CF), and applied to RPUF, which not only realized the regeneration of resources, but also provided RPUF with better thermal stability, flame retardancy and smoke suppression properties. The experimental results showed that when 3 wt% CoSn(OH)6 was added, the RPUF (CF1/MMT3/Co3) had the greatest activation energy. In addition, the peak heat release rate (PHRR) and total heat release (THR) of CF1/MMT3/Co3 decreased by 12.73%, and 11.16% respectively, compared with no CoSn(OH)6. In addition, its Ds decreased by 28.9% and the light transmittance increased by 17.6% compared with the RPUF without CoSn(OH)6. At the same time, its peak smoke production rate (PSPR) and the total smoke release (TSR) decreased by 25% and 18%. And CF1/MMT3/Co3 also had the lowest fire risk evaluation index. This study presented possibilities for practical utilization of the RPUF substances founded on bio-based flame inhibitors.

Identification of the S genotype of Malus plants will greatly promote the discovery of new genes, the cultivation and production of apple, the breeding of new varieties, and the origin and evolution of self-incompatibility in Malus plants. In this experiment, 88 Malus germplasm resources, such as Aihuahong, Xishuhaitang, and Reguanzi, were used as materials. Seven gene-specific primer combinations were used in the genotype identification. PCR amplification using leaf DNA produced a single S-RNase gene fragment in all materials. The results revealed that 70 of the identified materials obtained a complete S-RNase genotype, while only one S-RNase gene was found in 18 of them. Through homology comparison and analysis, 13 S-RNase genotypes were obtained: S1S2 (Aihuahong, etc.), S1S28 (Xixian Haitang, etc.), S1S51 (Hebei Pingdinghaitang), S1S3 (Xiangyangcun Daguo, etc.), S2S3 (Zhaiyehaitang, etc.), S3S51 (Xishan 1), S3S28 (Huangselihaerde, etc.), S2S28 (Honghaitang, etc.), S4S28 (Bo 11), S7S28 (Jiuquan Shaguo), S10Se (Dongchengguan 13), S10S21 (Dongxiangjiao) and SeS51 (Xiongyue Haitang). Simultaneously, the frequency of the S gene in the tested materials was analyzed. The findings revealed that different S genes had varying frequencies in Malus resources, as well as varying frequencies between intraspecific and interspecific. S3 had the highest frequency of 68.18%, followed by S1 (42.04%). In addition, the phylogenetic tree and origin evolution analysis revealed that the S gene differentiation was completed prior to the formation of various apple species, that cultivated species also evolved new S genes, and that the S50 gene is the oldest S allele in Malus plants. The S1, S29, and S33 genes in apple-cultivated species, on the other hand, may have originated in M. sieversii, M. hupehensis, and M. kansuensis, respectively. In addition to M. sieversii, M. kansuensis and M. sikkimensis may have also played a role in the origin and evolution of some Chinese apples.

In this study, fruits of the red flesh Malus plant ‘Hongxun 2’ (Malus neidzwetzkyana (Dieck) Langenf.) and green flesh Malus plant ‘Xinye 13-11’ (Malus sieversii (Led.) Roem.) were used as experimental materials. Both of them came from Xinjiang, China, and Malus neidzwetzkyana (Dieck) Langenf. is believed to be a variant of Malus sieversii (Led.) Roem. The components and contents of polyphenols in the peel and pulp of the two kinds of fruit during the development period were detected, and the dynamic changes and differences in the polyphenols between the two kinds of fruit were discussed. The results showed that the total polyphenol content of ‘Xinye 13-11’ was higher in the peel and pulp than that of ‘Hongxun 2’, and the content of peel was higher than that of pulp in the two kinds of fruit. An analysis of five types of polyphenols showed that anthocyanins were only contained in the peel and pulp of ‘Hongxun-2’, and the peel had a higher content than the pulp. Cyanidin 3-O-galactoside was the main anthocyanin component. Four other types of substances, except hydroxycinnamics, were higher in ‘Hongxun-2’ than ‘Xinye 13-11’, while the contents of other substances in ‘Xinye 13-11’ were higher than those of ‘Hongxun 2’. The accumulation of major polyphenol components in the peel and flesh of ‘Hongxun 2’ and ‘Xinye 13-11’ apples was significant in the period before and after 65 days after flowering, and the contents of procyanidin B1 and procyanidin C1 were the highest in this period. In addition to the difference in anthocyanin content between ‘Hongxun 2’ and ‘Xinye 13-11’, the chlorogenic acid content in the peel and pulp of ‘Hongxun 2’ was significantly higher than that of ‘Xinye 13-11’, and the contents of other components were lower than those of ‘Xinye 13-11’. Moreover, based on the components and contents of polyphenol components, this paper supports the viewpoint that Malus neidzwetzkyana (Dieck) Langenf is a separate species to Malus sieversii (Led.) Roem.

Polyphenols are important functional components that have anti-cancer and anti-inflammatory effects. Apple fruit is rich in polyphenols and is one of the dietary sources of polyphenols. The polyphenol components and contents of the peel and pulp of 74 Malus sieversii (Led.) Roem. and 26 Chinese Malus germplasm resources were determined using ultra-high-phase chromatography (UPLC) and liquid chromatography–mass spectrometry (LC–MS). The results showed that 34 components were detected in the peel and 30 in the flesh, and that the polyphenol components and contents of the different germplasm resources were significantly different; the polyphenol content of Malus sieversii (Led.) Roem. was significantly higher than that of the other local varieties, and the polyphenol content in the peel was also higher than that in the flesh. Rutin, quercetin 3-O-arabopyranoside, kaempferol 3-O-rutinoside, and peonidin 3-O-galactoside were detected only in the peel. The total polyphenol content in the peel ranged from 949.76 to 5840.06 mg/kg, and the polyphenol content in the pulp ranged from 367.31 to 5123.10 mg/kg. The cluster analysis of polyphenol components and contents in peel and pulp showed that 100 Malus germplasm resources could be grouped into four categories. Principal component analysis of 34 kinds and 30 kinds of polyphenols in peel and pulp of 100 resources was performed. If the eigenvalue is greater than 1, eight and seven principal components are extracted, respectively. Five Malus resources with high polyphenol content in the peel and pulp were selected: ‘XY-77’ (peel: 5840.06 mg/kg, pulp: 5123.10 mg/kg; ‘LF-09’ (peel: 4692.63 mg/kg, pulp: 3729.79 mg/kg); ‘2012-5’ (peel: 4377.61 mg/kg, pulp: 3847.54 mg/kg); ‘29028’ (peel: 5088.05 mg/kg, pulp: 3994.61 mg/kg); and ‘11-01’ (peel: 5154.45 mg/kg, pulp: 3616.15 mg/kg). These results provide us with information regarding the polyphenol composition and content of the wild apple resources and local cultivars. The high polyphenol content resources obtained by screening can be used as raw materials for the extraction of polyphenol components and functional fruit juice processing and can also be used as parents for functional fruit creation and variety breeding.

‘Binzi’ (BZ) (Malus domestica subsp. chinensis var. binzi Li Y.N.) and ‘Xiangguo’ (XG) (Malus domestica subsp. chinensis var. xiangguo Li Y.N.) are the ancient cultivars in China. The BZ fruits have a low-fragrant flavor on harvest day but a high-fragrant flavor after storage at room temperature, while the XG fruits have a stronger flavor when mature. ‘Starking’ (SK) and ‘Golden Delicious’ (GD) fruits have a rich flavor and are recognized by all countries in the world. However, information on the differences between ancient Chinese cultivars and Western apple cultivars in aroma compounds remains unknown. The apple fruits were collected for continuous two years. Aroma compounds in the skin and pulp of the fruits were detected at room temperature (20 ± 1 °C) during storage. The dynamics of VOCs in BZ and SK fruits were more similarly reflected in esters, while those of XG and GD fruits were reflected in aldehydes and alcohols. Ethyl 2-methylbutyrate, with an extremely low odor threshold, was the main source of typical apple flavor in SK, BZ, and XG fruits, while hexyl acetate was the source of the banana flavor in GD fruits. 6-methyl-5-hepten-2-one and β-damascenone were the important ketones produced in the later stage of storage, derived from the carotenoid metabolism pathway and providing a citrus and rose flavor to the four apple cultivars. SK had the highest number of characteristic aroma components, which were mainly derived from the amino acid metabolism pathway, providing fruits with a sweet and fruity flavor. Although the characteristic aroma components of GD were derived from the fatty acid metabolic pathway, the number of volatile esters was lower. Ethyl butyrate, derived from the saturated fatty acid metabolism, had the highest content in BZ, providing a pineapple flavor; the flavor of XG was mainly derived from ethyl 2-methylbutyrate, 6-methyl-5-hepten-2-one, and β-damascenone. Therefore, we suggest BZ and XG apples as the aroma-breeding material with which to enrich new cultivars’ aroma components, derived from the fatty acid metabolism and carotenoid metabolism pathways, respectively.

We used 256 apple germplasm resources for a thorough examination of the genetic diversity associated with 26 phenotypic traits (i.e., genetic diversity analysis, cluster analysis, correlation analysis, principal component analysis, and membership function). The average coefficient of variation for 12 morphological traits was 66.39% (21.10–201.5%). The coefficient of variation was highest and lowest for the fruit arris and the width of the eye basin, respectively. Additionally, the diversity index ranged from 0.54 to 1.33. Moreover, the coefficient of variation for 14 numerical traits varied from 5.37% to 50%. The titratable acid content had the highest coefficient of variation, with a diversity index ranging from 2.01 to 2.08 (average of 2.045). A cluster analysis categorized 256 germplasms into four groups, among which Group I included germplasms with large fruits and the best comprehensive performance. Of the top 10 principal components revealed by the principal component analysis, principal component 1 was mainly related to fruit size and flavor. The top 10 germplasms were selected on the basis of comprehensive scores using the membership function method. Furthermore, a stepwise regression analysis identified 15 key traits for identifying apple germplasms, including the vegetative growth day, fruit weight, and the firmness of the fruit without skin. These results can serve as the foundation for future analyses of the phenotypic diversity of apple germplasms, while also providing a theoretical basis for screening, characterizing, and further improving excellent apple germplasms.

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.

Under the influence of different types of disinfectants and disinfection environments, the removal level of pathogens and the formation potential of disinfection by-products (DBPs) will have a dual impact on the groundwater environment. The key points for sustainable groundwater safety management are how to balance the positive and negative relationship and formulate a scientific disinfection model in combination with risk assessment. In this study, the effects of sodium hypochlorite (NaClO) and peracetic acid (PAA) concentrations on pathogenic E. coli and DBPs were investigated using static-batch and dynamic-column experiments, as well as the optimal disinfection model for groundwater risk assessment was explored using quantitative microbial risk assessment and disability-adjusted life years (DALYs) models. Compared to static disinfection, deposition and adsorption were the dominant factors causing E. coli migration at lower NaClO levels of 0–0.25 mg/L under dynamic state, while disinfection was its migration factor at higher NaClO levels of 0.5–6.5 mg/L. In contrast, E. coli removed by PAA was the result of the combined action of deposition, adsorption, and disinfection. The disinfection effects of NaClO and PAA on E. coli differed under dynamic and static conditions. At the same NaClO level, the health risk associated with E. coli in groundwater was higher, whereas, under the same PAA conditions, the health risk was lower. Under dynamic conditions, the optimal disinfectant dosage required for NaClO and PAA to reach the same acceptable risk level was 2 and 0.85 times (irrigation) or 0.92 times (drinking) of static disinfection, respectively. The results may help prevent the misuse of disinfectants and provide theoretical support for managing twin health risks posed by pathogens and DBPs in water treatment.

Apple (Malus Mill.) is one of the most important fruits in China, and it boasts the world’s largest cultivation area and yield. It needs to be grafted onto rootstocks to maintain a variety of characteristics. China has many apple rootstock resources that exhibit high resistance and strong adaptability; for these reasons, they are highly suited to China’s complex and diverse natural environment. In China, apple rootstock breeding began in the 1970s, and now, several rootstocks, such as the ‘GM256’ and ‘SH’ series, are widely used. However, domestic rootstock resources and varieties are difficult to root. This affects the selection, utilization, and promotion of apple rootstocks. Cutting is an important method of rooting for apple rootstocks. This study discusses the main factors that affect rooting in rootstock cutting propagation; it also summarizes the rooting ability of different apple rootstocks and presents analyses of the demand for rootstocks in the major areas of apple production in China. We present the apple rootstock resources that are suitable for the soil and climate conditions of this production. We also call for research on the cutting roots of these specific apple rootstock resources to be expanded and strengthened. It is hoped that cutting rootstocks suitable for major areas of apple production may be more easily screened and bred successfully in China in the near future.

In this study, we used genotyping to determine the genetic structure and molecular identities of apple landraces from six species of Malus Mill. in China, based on the fingerprints revealed by microsatellite markers with tailed primer M13. A total of 46 apple landraces of Malus Mill. selected from the National Apple and Pear Germplasm Repository in Xingcheng, China were genotyped with 14 SSR markers. The primers differentiated all the accessions. At least three SSR primers, CH04h02, CH01f07a and CH04g07, with a higher heterozygosity and Shannon’s information index than other combinations can distinguish all the accessions. All the alleles for these three primers were arranged in descending order, and they were assigned values beginning with 01. Character strings were constituted by combining all the codes of the three primers for every accession. By such means, separate and special molecular identities were obtained for every apple landrace, which could be expressed in the form of a bar code. Using such bar codes, trees can be labeled and scanned, which aids in the identification and tracking of genebank collections. The eight-step method for establishing the molecular identities of apple landraces reported here may serve as a reference when determining the molecular identities establishment of other apple germplasms of Malus Mill. This method might also be used for the establishment of a molecular database to aid the preservation of Malus Mill., which is in imminent danger in China. It may also be used to improve the gene bank management of Malus Mill.

Understanding the different physiological responses of Malus species under salt stress in the seedling stages will be useful in breeding salt-tolerant dwarfing apple rootstocks. Seedlings of Malus Zumi (Mats.) Rehd. (M. zumi), Malus sieversii (Led.) Roem. (M. sieversii), and Malus baccata (L.) Borkh. (M. baccata) were treated with solution of 0, 0.20%, 0.40%, and 0.60% salinity. Physiological parameters of their leaves and roots were measured at 0 d, 4 d, 8 d and 12 d after salinity treatments. Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), malondialdehyde (MDA), solution protein (SP), and proline (PRO) initially increased and then decreased. The activities and contents of these parameters were higher in the 0.40% and 0.60% NaCl treatments than in the 0.20% treatment and in the 0% control. M. zumi was the most resistant to salt stress, showing the lowest content of MDA in the leaves and roots, which increased slightly under salt stress. M. baccata had the highest increase in both the content and proportion of MDA. High enzyme activity was shown to play an important role in the salt resistance of M. zumi. Moreover, it can be speculated that there are other substances that also play a major role. We found that osmotic regulation played a key role in response to salt stress for M. baccata even though it was sensitive to salt stress. For M. sieversii, both the osmotic regulation and enzymatic antioxidants were observed to play a major role in mitigating salt stress.

‘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.

Electrospinning and silver mirror reaction (SMR) were combined to synthesize silver nanowire membrane. The best sheet resistance (Rs) and transmittance (T) values reach around 15 O/sq and 80% on PET, 37 O/sq and 81% on glass, respectively. In this method, Poly (acrylonitrile - co - phenylethylene) (P(AN-S)) nanofibers act as the templates and reduction of silver on the nanofibers surface act as seeds. In SMR process, silver deposited on the surface of nanofibers and developed into silver nanowires. The membrane was characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The effects of spinning parameters and silver mirror reaction time on membrane properties were investigated. This process is easily controlled and it takes place at ambient condition, which gives a new opportunity for transparent conducting flexible electronics. [ABSTRACT FROM AUTHOR]