RsERF40 contributes to cold stress tolerance and cell expansion of taproot in radish (Raphanus sativus L.)

The growth and development of taproots are inhibited by cold stress in radish(Raphanus sativus L.).Ethylene-responsive element binding factors(ERF)are key participators in the cold stress response and growth regulation of plants.However,the function of ERF genes in cold tolerance and root development in radish remains elusive.Here,we showed that the secondary growth of radish taproots was inhibited by cold stress.Comparative transcriptome analysis demonstrated that the RsERF40 gene is an important regulator of the cold stress response and root growth regulation.The cold tolerance of transgenic Arabidopsis plants overexpressing the RsERF40 gene was significantly improved.Overexpressing RsERF40 in the cold-sensitive radish genotype and silencing RsERF40 in the cold-tolerant radish genotype indicated that RsERF40 was beneficial for alleviating oxidative damage under cold stress in radish.Transgenic Arabidopsis seedlings showed an increase in the elongation and radial growth of dark-grown roots.RT-qPCR analysis showed that the expression of the cold-related genes(CORs)RsCOR78 and RsCOR413PM1 and the cell wall strengthening-related genes RsCESA6 and RsEXPB3 was upregulated in transgenic Arabidopsis seedlings.Yeast one-hybrid(Y1H)and dual-luciferase reporter assays(DLA)revealed that RsERF40 directly regulates RsCOR78,RsCOR413PM1,RsCESA6 and RsEXPB3 expression,illustrating that RsERF40 enhances cold tolerance and taproot growth by modulating osmotic adjustment and cell wall mechanical strength in radish.In this study,the RsERF40-regulon was firstly found to be a new cold response pathway independent of the CBF-COR pathway conferring cold stress tolerance with increasing radish taproot growth.These results provided novel insight into the molecular mechanism underlying cold stress response and would facilitate the genetic improvement of cold tolerance in radish and other root vegetable crops.

Black radish root extract alleviates sodium valproate-induced liver damage via inhibiting mitochondrial membrane potential collapse and oxidative stress in mice

Objective:To explore the effect of black radish(Raphanus sativus L.var niger)root extract on liver enzymes,oxidative stress,and histopathological alterations in mice with sodium valproate-induced hepatotoxicity.Methods:Thirty-two mice were divided into four groups:the control group received drinking water by gavage,the second group was administered with 100 mg/kg of sodium valproate,the third group received 300 mg/kg of black radish root extract,and the fourth group was given both sodium valproate(100 mg/kg)and black radish root extract(300 mg/kg).After 28 days,the mice were euthanized,and serum levels of aspartate aminotransferase(AST),alanine aminotransferase(ALT),and alkaline phosphatase(ALP),along with liver malondialdehyde(MDA),reactive oxygen species(ROS),mitochondrial parameters,tumor necrosis factor-alpha(TNF-α)gene expression,and histopathological changes were assessed.Results:Sodium valproate caused hepatic damage in mice,characterized by elevated serum levels of liver enzymes,increased MDA and ROS levels and TNF-αgene expression,as well as histopathological alterations.The black radish root extract significantly alleviated sodium valproate-caused hepatic injury by decreasing the serum levels of ALT and AST,MDA,ROS,TNF-αgene expression,as well as mitochondrial impairment,but did not have a significant effect on sodium valproate-induced histopathological changes.Conclusions:The black radish root extract demonstrates protective effects against sodium valproate-induced liver injury,possibly through mitigating oxidative stress,mitochondrial impairment,and inflammatory mediator expression.

Establishing VIGS and CRISPR/Cas9 techniques to verify RsPDS function in radish

Virus-induced gene silencing(VIGS)and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein(CRISPR/Cas)systems are effective technologies for rapid and accurate gene function verification in modern plant biotechnology.However,the investigation of gene silencing and editing in radish remains limited.In this study,a bleaching phenotype was generated through the knockdown of RsPDS using tobacco rattle virus(TRV)-and turnip yellow mosaic virus(TYMV)-mediated gene silencing vectors.The TYMV-mediated gene silencing efficiency was higher than the TRV-based VIGS system in radish.The expression level of RsPDS was significantly inhibited using VIGS in'NAU-067'radish leaves.The rootless seedlings of‘NAU-067'were infected with Agrobacterium rhizogenes using the 2300GN-Ubi-RsPDS-Cas9 vector with two target sequences.Nine adventitious roots were blue with GUs staining,and four of these adventitious roots were edited at target sequence 1 of the RsPDS gene as indicated by Sanger sequencing.Furthermore,albino lines were generated with A.tumefaciens-mediated transformation of radish cotyledons.Five base substitutions and three base deletions occurred at target sequence 2 in Line 1,and three base insertions and three base substitutions occurred at target sequence 1 in Line 2.This study shows that VIGS and CRISPR/Cas9 techniques can be employed to precisely verify the biological functions of genes in radish,which will facilitate the genetic improvement of vital horticultural traits in radish breeding programs.

Oxytetracycline Uptake and Growth of Radish Plants (Raphanus sativus L.) in Animal Manureamended Soils

[Objective] Antibiotics are extensively given to livestock to promote its growth and reduce its diseases.Therefore,antibiotics may be present in manure and slurry from their parent compound and/or metabolites.The soil environments may be exposed to these antibiotics due to the application of animal manure to agricultural land.So,in this study,accumulation and phytotoxicity indicators were analyzed to evaluate the effects of oxytetracycline （OTC,C22H24N2O9HCI） on vegetable crop.[Method] A pot experiment was conducted in the greenhouse,radish plant （Raphanus sativus L.） was grown for seven weeks in two soils （sand soil and clayey soil） that were amended with pig manure and spiked with six levels （0,2,5,10,25 and 50 mg per kg of soil） of oxytetracycline for observing the potential effects of long-term application of antibiotics-contained animal manure on plant growth and determining whether or not radish plant grown in manure-applied soils absorbs OTC present in the soils.Contents of oxytetracycline in both root and shoot tissues were determined,and effects of soil oxytetracycline pollution on photosynthesis and biomass of the plant were monitored.[Result] The results showed that radish plant can absorb OTC from the soils.The concentration of OTC in plant tissues increased with increasing the concentration of OTC present in the soils,and was higher at the initial growth stage than at last stage of the plant.Higher concentration of OTC was found in roots than shoots of the plant.Bioavailability of OTC in the sandy soil was greater than that in clayey soil.OTC did not affect the growth of the plants when its concentration in the soils was less than 10 mg/kg.However,higher concentration of soil OTC （＞25 mg/kg） caused serious stress in the plant,reducing photosynthetic rate of leaves and biomass of both roots and shoot.[Conclusion] This study points out the potential human health risk associated with consumption of fresh vegetable grown in the soils amended with antibiotic laden manures.

Analysis and Evaluation of Nutritional Quality in Chinese Radish (Raphanus sativus L.)

Radish （Raphanus sativus L.） is an important vegetable crop worldwide. High nutritional quality was critical in its genetic improvement and production. The nutritional quality of 42 Chinese radish cultivars was analyzed in this study. The contents of six nutritional facts, dry matter （DM）, crude fiber （CF）, total soluble sugar （TSS）, vitamin C （Vc）, protein, and nitrate, ranged from 29.7 to 88.2, 4.507 to 18.546, 2.233 to 15.457, 0.1416 to 0.3341, 0.34 to 1.15, and 1.81 to 5.89 g·kg^-1 fresh weight （FW）, respectively. Significant differences among the 42 radish cultivars were detected in the contents of nutritional facts. The data were subjected to cross-correlation analysis and principal component analysis （PCA）. It was found that DM content was positively correlated with the content of TSS （r=0.7104）, Vc （r=0.4011） and protein （r=0.4120）. Vitamin C （Vc） content of radish showed a positive correlation （r = 0.3300） with the protein content. According to the principal component analysis, out of the 42 radish cultivars, Nau-17, Nau-28, Nau-6, Nau-11, Nau-10, Nau-27, and Nau-31 were detected with very high scores in comprehensive evaluation. It could be concluded that abundant diversity of nutritional fact content occurred in different radish genotypes, and PCA analysis was effective for selecting radish germplasm with high quality. The results could contribute useful knowledge of nutritional quality, and provide important germplasms for the elite cultivar development and the inheritance study of nutritional facts in radish.

Effect of Brassinosteroids on Germination and Seedling Growth of Radish (<i>Raphanus sativus</i>L.) under PEG-6000 Induced Water Stress

Effect of 24-epibrassinolide and 28-homobrassinolide on the germination and seedling growth of radish (Raphanus sativus) subjected to water stress being imposed by 15% (w/v) polyethylene glycol (equivalent to -2.95 bars of osmotic pressure) was studied. Brassinosteroids supplementation reduced the inhibitory effect of water stress on seed germination and seedling growth. The growth stimulation in radish seedlings by brassinosteroids under desiccation stress was associated with elevated levels of nucleic acids and soluble proteins and lowered activities of RNase. The mitigation of osmotic stress imposed by PEG was associated with increased scavenging of reactive oxygen species as reflected in elevated activities of superoxide dismutase, catalase and ascorbate peroxidase. Brassinosteroids also enhanced the accumulation of the osmolyte free proline in radish seedlings challenged with drought stress. The two brassinosteroids also maintained membrane integrity under water deficiency conditions as indicated by lowered lipid peroxidation reflecting in reduced MDA content. The results of present study demonstrate the protective role of brassinosteroids against PEG imposed water stress in radish seedlings.

Osmoprotectants and Antioxidative Enzymes as Screening Tools for Salinity Tolerance in Radish (Raphanus sativus)

The research addresses the identification of a screening methodology for salt stress tolerance in radish cultivars. In the first experiment, two different radish cultivars(long white and round red) were compared in their morphological and physiological responses to different salinity levels. Round red radish showed better morphological and physiological responses to incremental salinity in terms of yield and better adaptation of overall water relations. In the second experiment, the most tolerant genotype from the first experiment was used as a control against other seven round red radish genotypes ranked by their salinity tolerance according to morphological, physiological and biochemical indices. Salt stress did not significantly affect malondialdehyde(MDA) and hydrogen peroxide(H2O2) content, and ascorbate peroxidase(APX) activity in the studied cultivars. Nonetheless, the relatively salt tolerant cultivar SAXA2 showed higher ability to accumulate compatible solutes(e.g.proline and proteins) and maintain osmotic adjustment. In addition, cultivar SAXA2 also showed considerable increase in glutathione reductase(GR) activity. Our results supported that accumulation of proline and higher GR activity are associated with radish salt tolerance, whereas no relationship with salinity was observed in superoxide dismutase(SOD), MDA and H2O2 content.

Molecular Characterization and Expression Profiles of Myrosinase Gene(RsMyr2) in Radish(Raphanus sativus L.)

Myrosinase is a defense-related enzyme and is capable of hydrolyzing glucosinolates into a variety of compounds, some of which are toxic to pathogens and herbivores. Many studies revealed that a number of important vegetables or oil crops contain the myrosinase-glucosinolate system. However, the related promoter and genomic DNA sequences as well as expression profiles of myrosinase gene remain largely unexplored in radish（Raphanus sativus）. In this study, the 2 798 bp genomic DNA sequence, designated as RsMyr2, was isolated and analyzed in radish. The RsMyr2 consisting of 12 exons and 11 introns reflected the common gene structure of myrosinases. Using the genomic DNA walking approach, the 5′-flanking region upstream of RsMyr2 with length of 1 711 bp was successfully isolated. PLACE and PlantCARE analyses revealed that this upstream region could be the promoter of RsMyr2, which contained several basic cis-regulatory elements including TATA-box, CAAT-box and regulatory motifs responsive to defense and stresses. Furthermore, recombinant pET-RsMyr2 protein separated by SDS-PAGE was identified as myrosinase with mass spectrometry. Real-time PCR analysis showed differential expression profiles of RsMyr2 in leaf, stem and root at different developmental stages（e.g., higher expression in leaf at cotyledon stage and lower in flesh root at mature stage）. Additionally, the RsMyr2 gene exhibited up-regulated expression when treated with abscisic acid（ABA）, methyl jasmonate（MeJA） and hydrogen peroxide（H2O2）, whereas it was down-regulated by wounding（WO） treatment. The findings indicated that the expression of RsMyr2 gene was differentially regulated by these stress treatments. These results could provide new insight into elucidating the molecular characterization and biological function of myrosinase in radish.

Genome-wide identification and expression profiling of MYB transcription factor genes in radish(Raphanus sativus L.)

Radish(Raphanus sativus L.), an important root vegetable crop of the Brassicaceae family, has a high level of anthocyanin accumulation in its pigment root tissues. It was reported that MYB transcription factors(TFs) play vital roles in plant development and anthocyanin metabolism, and the PAP1/2 could promote expression of anthocyanin biosynthesis genes. In this study, a total of 187 radish MYB genes(Rs MYBs) were identified in the radish genome and clustered into 32 subfamilies. Among them, 159 Rs MYBs were localized on nine radish chromosomes. Interestingly, 14 Rs MYBs exhibited differential expression profiles in different taproot developmental stages among four differently colored radish lines. A number of Rs MYBs were highly expressed in the pigmented root tissues at the maturity stage, several genes including Rs MYB41, Rs MYB117, and Rs MYB132 being homologous to PAP1/2, showed high expression levels in the red skin of NAU-YH(red skin-white flesh) taproot, while Rs MYB65 and Rs MYB159 were highly expressed in the purple root skin of NAU-YZH(purple skin-red flesh), indicating that these Rs MYBs might positively regulate the process of anthocyanin accumulation in radish taproot. These results would provide valuable information for further functional characterization of Rs MYBs, and facilitate clarifying the molecular mechanism underlying anthocyanin biosynthesis in radish.

Evaluation of Different Radish (Raphanus sativus) Genotypes under Different Saline Regimes

An effective and simple screening technique for identification of salt tolerant and salt sensitive radish genotypes was observed. Sand is used as potting media. Six genotypes of radish were used for screening against four salinity levels (0, 1, 3, 5 and 7 dS/m-1). Twenty days old seedlings of radish were salinized with salt solution (NaCl). Morphological, physiological and ionic parameters were studied. Radish genotypes Laal-Pari and 40 Days executed the best performance in all the measured attributes and categorized as salt tolerant genotype while Green Neck was the poorest in retaining normal functioning at higher salinity levels thus grouped under salt sensitive cultivar.

Comparative proteomic analysis provides insight into a complex regulatory network of taproot formation in radish (Raphanus sativus L.)

The fleshy taproot of radish is an important storage organ determining its yield and quality.Taproot thickening is a complex developmental process in radish.However,the molecular mechanisms governing this process remain unclear at the proteome level.In this study,a comparative proteomic analysis was performed to analyze the proteome changes at three developmental stages of taproot thickening using iTRAQ approach.In total,1862 differentially expressed proteins(DEPs)were identified from 6342 high-confidence proteins,among which 256 up-regulated proteins displayed overlapped accumulation in S1(pre-cortex splitting stage)vs.S2(cortex splitting stage)and S1 vs.S3(expanding stage)pairs,whereas 122 up-regulated proteins displayed overlapped accumulation in S1 vs.S3 and S2 vs.S3 pairs.Gene Ontology(GO)and pathway enrichment analysis showed that these DEPs were mainly involved in several processes such as“starch and sucrose metabolism”,“plant hormone signal transduction”,and“biosynthesis of secondary metabolites”.A high concordance existed between iTRAQ and RT-qPCR at the mRNA expression levels.Furthermore,association analysis showed that 187,181,and 96 DEPs were matched with their corresponding differentially expressed genes(DEGs)in S1 vs.S2,S1 vs.S3,and S2 vs.S3 comparison,respectively.Notably,several functional proteins including cell division cycle 5-like protein(CDC5),expansin B1(EXPB1),and xyloglucan endotransglucosylase/hydrolase protein 24(XTH24)were responsible for cell division and expansion during radish taproot thickening process.These results could facilitate a better understanding of the molecular mechanism underlying taproot thickening,and provide valuable information for the identification of critical genes/proteins responsible for taproot thickening in root vegetable crops.

Identification and Molecular Mapping of the Rs Dm R Locus Conferring Resistance to Downy Mildew at Seedling Stage in Radish(Raphanus sativus L.)

Downy mildew （DM）, caused by the fungus Peronospora parasitica, is a destructive disease of radish （Raphanus sativus L.） worldwide. Host resistance has been considered as an attractive and environmentally friendly approach to control the disease. However, the genetic mechanisms of resistance in radish to the pathogen remain unknown. To determine the inheritance of resistance to DM, F1, F2 and BC1F1 populations derived from reciprocal crosses between a resistant line NAU-dhp08 and a susceptible line NAU-qtbjq-06 were evaluated for their responses to DM at seedling stage. All F1 hybrid plants showed high resistance to DM and maternal effect was not detected. The segregation for resistant to susceptible individuals statistically iftted a 3：1 ratio in two F2 populations （F2（SR） and F2（RS））, and 1：1 ratio in two BC1F1 populations, indicating that resistance to DM at seedling stage in radish was controlled by a single dominant locus designated as RsDmR. A total of 1 972 primer pairs （1 036 SRAP, 628 RAPD, 126 RGA, 110 EST-SSR and 72 ISSR） were screened, and 36 were polymorphic between the resistant and susceptible bulks, and consequently used for genotyping individuals in the F2 population. Three markers （Em9/ga24370, NAUISSR826700 and Me7/em10400） linked to the RsDmR locus within a 10.0 cM distance were identiifed using bulked segregant analysis （BSA）. The SRAP marker Em9/ga24370 was the most tightly linked one with a distance of 2.3 cM to RsDmR. These markers tightly linked to the RsDmR locus would facilitate marker-assisted selection and resistance gene pyramiding in radish breeding programs.

Identification and Analysis of Components of Glucosinolates in Succulent Roots and Leaves of Fruity Radish (Raphanus sativas L.)

The components of glucosinolates( GSL) in the succulent roots and leaves of three kinds of fruity radish( Xinlimei,Super Zhengyan,and Shawo) were identified and analyzed by high performance liquid chromatography( HPLC). Results showed that there were nine kinds of glucosinolates in the succulent roots and leaves of three kinds of fruity radish,including six kinds of aliphatic glucosinolates( 4-methyl sulfinyl-3-butenyl glucosinolates,2-allyl glucosinolates,4-methyl sulfinyl butyl glucosinolates,5-methyl sulfinyl amyl glucosinolates,4-methyl n-butyl glucosinolates,4-methyl thio-3-butenyl glucosinolates) and three kinds of indole glucosinolates( 4-methoxy methyl indole glucosinolates,3-methyl indole glucosinolates,1-methoxy methyl indole glucosinolates),but there were significant differences in the content of glucosinolates between different varieties and organs. The total content of glucosinolates in succulent roots of three kinds of fruity radish was22 472. 84,13 585. 86,and 28 200. 70 μg/g DM respectively,and more than 95% were aliphatic glucosinolates. The content of glucosinolates in succulent roots was 4. 56,2. 71,and 4. 55 times of that in leaves of three kinds of fruity radish. Main aliphatic glucosinolates in succulent roots and leaves of three kinds of fruity radish were 4-methyl sulfinyl-3-butenyl glucosinolates,accounting for 90. 11%-93. 92% and63. 03%-73. 72% of total content of glucosinolates.

Comparative Effect of City Finished Compost and NPK Fertilizer on Growth and Availability of Phosphorus to Radish (<i>Raphanus sativus</i>L.)

A pot experiment was carried out to investigate the comparative effect of city finished compost and NPK fertilizer on the growth and availability of phosphorus to radish (Raphanus sativus L.). An air dried sandy loam soil was mixed with five rates of city finished compost (CFC) equivalent to 0, 5, 10, 20, 40 ton ha–1 and three rates of NPK fertilizer equivalent to 50% (N-P-K = 69-16-35 kg ha–1), 100% (N-P-K = 137-32-70 kg ha–1 K) and 150% (N-P-K = 206-48-105 kg ha–1). Four plants were harvested at 45 days of growth and remaining one plant was harvested at 90 days of growth and separated into leaves and bulbs. After harvest, soil samples were collected from each pot to measure soil pH and available P extracted by Olsen, Mehlich-3, Kelowna and Bray & Kurtz-1 extractants. The growth parameters (length of leaves and bulbs, fresh and dry weight of leaves and bulbs), relative dry matter yield, plant P concentrations, P uptake by radish, soil pH, and available P increased by the rates of CFC and NPK fertilizer treatments. Among the treatments, growth performance of radish was better with the highest rate of 40 t ha–1 CFC treatments. The results obtained from the 5 and 10 t ha–1 CFC treatment were comparable with the results of 50% and 100% NPK fertilizer treatments respectively. Similar effects of amendments were obtained in the case of plant P concentration, uptake of P by plant, soil pH and available soil P concentration. Available P and soil pH showed very strong and positive correlation (P –1 city finished compost could be used instead of 100% to obtain similar yield and to improve soil conditions.

Anther Culture of Chinese Radish(Raphanus sativus L. var. Longinnatus Bailey):Response of Different Genotypes to the Embryogenesis and the Traits of Regenerated Plantlets

[Objective] The aims were to ① conduct anther culture of Chinese radish varieties; ② observe the development of embryos from anther culture; ③ study the response of different genotypes to embryogenesis in anther culture; ④ observe the morphology of regenerated plantlets; ⑤ analyze the ploidy level of regenerated plantlets arising from the anther culture process. [Method]Anthers of 15 genotypes with diverse genetic backgrounds of Chinese radish have been cultured in vitro and induced to undergo embryogenesis and plant formation. [Result] Of 15 genotypes evaluated,four produced embryos. The genotype was the main factor to influence the embryogenesis. The morphology and the ploidy of the regenerated plantlets were observed,and the anther-derived plantlets included a mix of haploids,diploids and hexaploids. Of the plants that regenerated from anther embryos 60% were diploid. [Conclusion] The plantlets had the high ability to double spontaneously.

Effect of plasma treatment on the seed germination and seedling growth of radish(Raphanus sativus)

The effect on the germination and seedling growth of radish(Raphanus sativus)seeds were examined employing a dielectric barrier discharge(DBD)at atmospheric pressure and room temperature for various treatment time.DBD plasma using argon gas of flow rate 21 m^(-1)was employed in this study.Radish seeds were treated with DBD plasma for 1-5 min,respectively.Germination characteristics,seedling growth parameters,the contact angle of the seed coat,water uptake capacity,mass loss,the temperature of the seeds,chlorophyll,and carotenoid contents of the seedlings were measured before and after the DBD plasma treatments.Plasma treatment of radish seeds significantly increased germination-related characters,including germination percentage,fresh and dry weight,vigor index,and total carotenoids contents.However,the cumulative production rate was found to be decreased.Results from the experiment indicate an acceleration in the water uptake of the radish seeds and make the seed surface hydrophilic by plasma treatment.Scanning electron microscopy analysis showed that etching effects on the seed coat occurred after the argon plasma treatments,which affected the wettability of the radish seed.The experimental findings showed that seeds being treated by DBD plasma for 2 and 3 min had a positive effect on the germination and seedling growth of radish.

Effects of Low Temperature Treatment on Bolting of Radish(Raphanus sativus L.)

[Objectives]This study was conducted to screen out a vernalization method of radish that is more suitable for breeding and hybrid production.[Methods]Eight radish inbred lines with different bolting tolerance were used as the research objects for the experiment.The following three treatments were done:(1)treating at 4℃in the dark with heat preservation for 1,2,3,4,and 5 weeks,respectively~([1]),(2)treating at 4℃in the dark with heat preservation for 3 weeks after 24 h incubation in light at 20℃,and(3)treating under light at a low temperature of 6.5℃for three weeks after cultivating under light at 20℃to 4 true leaves.The effects of low temperature treatment on the bolting and flowering time of different varieties of radish treated at different developmental stages were analyzed.[Results]When comparing these three methods,the low-temperature treatment of wet seeds had a better effect on early bolting of radish and is simpler and more feasible.The effect of treating four-leaf seedlings at 6.5℃was the worst;most radish inbred lines could shorten bolting time when treated at 4℃for one week;and within a certain range,the longer the 4℃treatment time,the better the vernalization effect.Different radish inbred lines had different performances to low temperature treatment.[Conclusions]This study provides a scientific basis for the theoretical research on vernalization of radish.

Efficient in Vitro Micropropagation System for Radish （Raphanus sativus L.） Var. Beeralu Rabu

This study was conducted to investigate the effects of explants and hormone combinations on the callogenesis, calli growth and regeneration of local variety of radish （Beeralu Rabu）. As well as three explant types： hypocotyl, leaf and root, seven hormone combination based on Murashige and Skoog （MS） medium as 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 mg/L 2,4-dichlorophenoxyacetic acid （2,4-D） with 0.1 mg/L 1-naphthaleneacetic acid （NAA） and without hormones （control） were employed. Then immerged calli were transferred to regenerate in MS with 0.1 mg/L NAA and 1.0, 1.5, 2.0, 2.5, 3.0 mg/L benzyl adenine （BA）. Healthy regenerated shoots were introduced to MS medium with 0.1, 0.25, 0.5, 0.75 and 1.0 mg/L indole-3-butyric acid （IBA） for rooting. After one month the callogenesis, diameter of fresh callus, shoots regeneration, number of regenerated shoots and roots were evaluated. Observations were made that, 0.5 mg/L 2,4-D with 0.1 mg/L NAA and hypocotyl explant of radish was the best showing significantly highest callus diameter （〉 2 cm）. Medium with 2.5 mg/L BA and 0.1 mg/L NAA was the best hormonal combination for the in vitro shoot regeneration （6.6 shoots/explant） while the highest number of roots were observed from MS medium with 0.25 mg/L.

Effects of Huangzhou Radish Powder on the Quality of Silver Carp Surimi Products

[Objectives]This study was conducted to improve the quality of frozen silver carp surimi products.[Methods]Huangzhou radish powder and silver carp surimi were used as raw materials to analyze the effects of different amounts(1%,2%,3%,4%,5%)of Huangzhou radish powder on the water-holding capacity,cooking loss rate,whiteness value,TPA,gel strength and sensory quality of surimi products.[Results]When the addition amount of Huangzhou radish powder was 1%,water-holding capacity,hardness,chewiness and the gel strength of the surimi product reached their maximum values,which were 86.86%,3470.36 g,2628.50 g and 707.48 g·mm,respectively.Meanwhile,the cooking loss rate was reduced to a minimum value(13.66%),and the sensory quality reached the best.The whiteness of surimi products showed a decreasing trend with the increase of the addition amount of Huangzhou radish powder.However,the whiteness of the surimi product was not significantly affected when the addition amount of Huangzhou radish powder was 1%.Therefore,when the addition amount of Huangzhou radish powder was 1%,the quality of surimi products could be improved.[Conclusions]This study provides a new idea for the development and utilization of Huangzhou radish.

萝卜叶多酚的超声波辅助提取工艺优化及抗氧化活性研究

为提高萝卜叶资源的利用率,并发掘其潜在应用价值,探究了萝卜叶多酚的超声波辅助提取工艺,并对其抗氧化活性进行了评估。通过在单因素实验基础上引入Box-Behnken响应面法,对萝卜叶多酚的超声波辅助提取工艺进行了优化。通过体外实验的评估,进一步验证了其抗氧化能力。结果表明,在超声温度为68℃、液料比为32 mL/g、乙醇体积分数为63%以及超声时间为31 min的最佳工艺条件下,萝卜叶多酚可以被高效地提取,其提取率达到了60.84 mg/g,且相对误差低至0.73%,充分证实了响应面分析方法优化该提取工艺的有效性和可行性。萝卜叶多酚展现出一定的抗氧化特性,对DPPH自由基、O_(2)^(-)自由基的半抑制质量浓度(half maximal inhibitory concentration,IC_(50))分别为78.91、403.55 mg/L,为进一步研发其作为天然植物源抗氧化剂提供了参考。