Research Papers

• Effects of Different Mulching Measures on Soil Properties，Bacterial Community，Fruit Yield and Quality of Luochuan Apple Orchard in Shaanxi Province
• SHEN Pengfei，WANG Weiyan，LI Tong，LIAO Yuncheng，LI Yajun*，and WEN Xiaoxia*
• Acta Horticulturae Sinica. 2019, 46(5): 817-831. DOI:10.16420/j.issn.0513-353x.2018-0863
• Abstract ( 506 ) HTML ( 853 ) PDF (1415KB) ( 853 ) 　　　
• Four types of mulching techniques（cornstalk mulch，sawdust mulch，forest soil mulch，control）in the dryland apple orchards of Weibei were tested in this study. Based on the determination of soil basic physical and chemical indicators and enzyme activity，the quantitative analysis of soil bacterial community structure and diversity under different coverage measures were carried out by using real-time PCR（q-PCR）and Illumina HiSeq high-throughput sequencing technology. The results showed that different mulching treatments significantly increased water content，organic matter and total nitrogen of 0–20 cm soil layer and reduced soil pH value. At the same time，soil urease，sucrase and catalase activities were remarkably improved. The results of real-time PCR indicated that the 16S rRNA copy number of soil bacteria under each covering treatment was observably higher than that of clear tillage. Illumina HiSeq high-throughput sequencing revealed that Proteobacteria，Acidophilus and Actinomycetes were dominant bacteria populations at phylum level whose relative abundances ranged from 57.12% to 74.72%；α-proteobacteria，subgroup_6，β-proteobacteria and δ-deformation were dominant at class level，and the relative abundances ranged from 33.39% to 43.15%. The α diversity analysis showed that different mulching treatments could increase the abundances and diversity indices of soil bacterial communities. The analysis of β diversity manifested that there were considerable differences in the phylogenetic compositions of each bacterial treatment compared to the control bacterial community. The results of RDA analysis showed that there were correlations between relative soil bacterial community abundances and soil nutrient and enzyme activities in the condition of different mulching treatments. These three mulching treatments had positive effects on 100-fruit weight and sugar content，among which cornstalk mulch was the best.
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• Functional Identification of Apple Anthocyanin Regulatory Gene MdMYB111
• YANG Guanxian，XU Haifeng，ZHANG Jing，WANG Nan，FANG Hongcheng，JIANG Shenghui，WANG Yicheng，SU Mengyu，and CHEN Xuesen*
• Acta Horticulturae Sinica. 2019, 46(5): 832-840. DOI:10.16420/j.issn.0513-353x.2018-0686
• Abstract ( 329 ) HTML ( 916 ) PDF (1497KB) ( 916 ) 　　　
• The fruit of‘Hongxin 16’apple，a progeny of Malus sieversii f. neidzwetzkyana hybrids，was used as the test material. MdMYB111 was cloned and its recombinant protein was induced and expressed in prokaryotic analysis. The bioinformatic analysis of this gene was conducted，its expression level was determined in the fruits of the varieties of‘Hongxin 16’and‘Hongcui 1’and its function was identified by transgene. The results showed that the open reading frame of MdMYB111 was 720 bp，encoding 239 amino acids，and its predicted protein size was 26.93 kD. Phylogenetic tree analysis showed that MdMYB111 and MdMYB16 were in the same clade and there was an EAR inhibitory sequence at the C-terminus of the protein. The ripened fruit of‘Hongxin 16’ is complete red and darker in color. The fruit of‘Hongcui 1’has a light red color and a small red range. On the‘Hongxin 16’，both the content of anthocyanin in fruits mature stage and MdANS，MdUFGT，MdMYB9，MdMYB10，MdMYB11 expression levels were higher than that of‘Hongcui 1’，but the expression levels of MdMYB16 and MdMYB111 were lower than‘Hongcui 1’. Overexpression of MdMYB111 in red apple callus can inhibit the expression of MdANS and MdUFGT and reduce the content of anthocyanin. In summary，MdMYB111 may be involved in the anthocyanin synthesis pathway and inhibit its synthesis.
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• Identification of Genes Related to Oil Gland Development in Kumquat by Using BSA-Seq
• LIU Mengyu，LIU Xiaofeng，JIANG Dong，ZHU Shiping，SHEN Wanxia，YU Xin，XUE Yang，and ZHAO Xiaochun*
• Acta Horticulturae Sinica. 2019, 46(5): 841-854. DOI:10.16420/j.issn.0513-353x.2018-0324
• Abstract ( 246 ) HTML ( 727 ) PDF (652KB) ( 727 ) 　　　

• The density of oil gland is an important factor to determine the content of essential oil in citrus. To understand the genetic control of oil gland development，a segregation population of 159 F1 individuals was constructed by crossing Luowen kumquat[Fortunella japonica（Thunb.）Swingle]with Huapi kumquat（F. crassifolia Swingle‘Huapi’），a low oil gland density mutation variety. Thirty individuals of each extreme phenotype group with either high-density or low-density oil glands were chosen and their DNA were pooled to construct two DNA pools for genomic re-sequencing to identify candidate genes associated with oil gland development. The results of Bulked Segregant Analysis（BSA）indicated that the 25 980 001–29 160 001 bp region of chromosome 9 is highly correlated to the density of oil glands. Through analysis of recombination frequency of SNP，511 SNP loci distributed in 301 genes were found to be possibly associated with the density of oil glands. The homology function analysis suggested that 11 of these genes（Ciclev10005243m.g，Ciclev10005288m.g，Ciclev10005338m.g，Ciclev10005441m.g，Ciclev10006448m.g，Ciclev10005804m.g，Ciclev10004719m.g，Ciclev10005888m.g，Ciclev10006502m.g，Ciclev10005197m.g and Ciclev10004431m.g）involving in cell programmed death，the function and construction of cell wall，and cell elongation and expansion may be the important genetic factors controlling the development of oil gland.

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• Bioinformatics and Expression Analysis of PpRGI Gene Family of Peach GLV Peptide Receptor
• WANG Yan1，WANG Xiaobei1，CHEN Haijiang2，CAO Hongbo2，NIU Liang1，PAN Lei1，LU Zhenhua1，CUI Guochao1，ZENG Wenfang1,*，and WANG Zhiqiang1,*
• Acta Horticulturae Sinica. 2019, 46(5): 855-863. DOI:10.16420/j.issn.0513-353x.2018-0690
• Abstract ( 340 ) HTML ( 633 ) PDF (1473KB) ( 633 ) 　　　

• In order to further understand the molecular mechanism of GLV peptide in peach fruit ripening and softening，the PpRGI gene family was identified in peach genome, and its expression levels during fruit development in melting flesh and stony hard peach were detected by qRT-PCR. Additionally，we also used qRT-PCR to detect the expression level of PpRGI gene family in stony-hard peach fruit under NAA treatment，and in peach callus under exogenous peptide treatment. The results showed that 6 PpRGI candidate genes were found in the peach genome. The PpRGI contained the LRR conserved domain and signal peptide at the N-terminus. The phylogenetic analysis revealed that PpRGI gene family was divided into 2 groups. Expression analysis showed that PpRGI1，PpRGI3 and PpRGI4 were expressed in different tissues of melting-flesh peach and their expression levels in melting-flesh peach fruits were higher than in stony-hard peach fruits. PpRGI1 has the highest expression in different peach types and the expression of PpRGI1 was increased under NAA and peptide treatment. These results suggested that the PpRGI gene family members are highly and structurally conserved and PpRGI1 may be involved in the biosignaling pathway of peach peptide hormones.

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• Cloning and Functional Analysis of microRNA171 in Cucumber
• ZHU Zaobing，YU Xiaqing*，ZHAI Yufei，WANG Panqiao，ZHAO Qinzheng，LI Ji，LOU Qunfeng，and CHEN Jinfeng*
• Acta Horticulturae Sinica. 2019, 46(5): 864-876. DOI:10.16420/j.issn.0513-353x.2018-0924
• Abstract ( 309 ) HTML ( 694 ) PDF (3209KB) ( 694 ) 　　　

• To investigate the function of microRNA171（miR171）in cucumber，four precursors Csa-miR171a，Csa-miR171b，Csa-miR171c，Csa-miR171d of Csa-miR171 family genes were cloned in the northern Chinese cucumber‘Beijingjietou’and followed by sequence alignment and phylogenetic analysis. Target genes of the mature sequence of Csa-miR171 were predicted and functional analysis was performed in Arabidopsis by genetic transformation. The results showed that the two mature sequences，Csa-miR171a and Csa-miR171b were cleaved from the four Csa-miR171 precursors. Phylogenetic analysis showed that Csa-miR171a，Csa-miR171b，Csa-miR171c，Csa-miR171d were closer to Cme-miR171e，Cme-miR171c，Cme-miR171a，Cme-miR171b in melon than those in Arabidopsis，rice and tomato，etc. GRAS transcription factor family was predicted to be the main target gene of Csa-miR171. Overexpression of Csa-miR171a in Arabidopsis significantly affected the phenotypes including leaf morphology and leaf color，blooming time，root，fruit and floral morphology.

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• A Pyrimidine Derivative Confers Cucumber Induced Resistance to Fusarium Wilt
• SHI Yanxia1，ZHANG Xiaohui1，XU Yufang2，XIE Xuewen1，CHAI Ali1，and LI Baoju1,*
• Acta Horticulturae Sinica. 2019, 46(5): 877-890. DOI:：10.16420/j.issn.0513-353x.2018-0438
• Abstract ( 164 ) HTML ( 543 ) PDF (6439KB) ( 543 ) 　　　

• In this study，a new type of disease-resistant activator named BDO-1，（E）-N-[2-fluoro-4-（trifluoromethyl）styryl]-1-met-hyl-1H-pyrazolo[3,4-d]pyrimidin-4-amine，which belongs to pyrazolium pyrimidine derivative was reported and studied. To reveal the resistance mechanism of BDO-1，the induced resistance effect of the activator to cucumber against Fusarium oxysporum f. sp. cucumerinum was investigated. The antifungal activity of BDO-1 was detected by using plate growth rate method，and the result showed that BDO-1 had no antagonistic effect against F. oxysporum. The leaves were treated with 10 mg · L-1 BOD-1 by foliar spraying method at two-leaf and one-hearted cucumber stage. A total of five times were induced in 25 days and the pathogen F. oxysporum was inoculated after 24 h of last induction.The induced assay results indicated that the induced resistance effect of BDO-1 to cucumber against F. oxysporum was 53.28%. In addition，laser confocal microscopy confirmed that the infection rates of F. oxysporum on cucumber were inhibited by induction of BDO-1. Meanwhile，fluorescence microscopy showed that the secondary metabolite callose accumulated in cucumber plants on the 3rd day post-inoculation，and the highest content of anti-oxidant H2O2 appeared in cucumber plants on the 1st day post-inoculation. Besides，qRT-PCR revealed that BDO-1 could induce expression of six disease-resistant defense genes. After BDO-1 induction，the expression levels of CAT，PAL，LOX and EIN2 in the defense genes of root defense tissues increased significantly from 1st day to 7th day post-inoculation，and the expression levels of PR1 and SOD were higher at 1st day post-inoculation，significantly reduced in 3rd day and 7th day post-inoculation. This study provides an insight and basis for the development and application of BDO-1 as a new type of disease-resistant activator.

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• Mechanisms of Foliar-spraying 1-MCP to Alleviate Injury of Pepper Seedlings Caused by High Temperature
• DENG Jiaoyan，HUANG Bin，Lü Lijun，WANG Jun，YU Xianchang，HE Chaoxing，YAN Yan，and LI Yansu*
• Acta Horticulturae Sinica. 2019, 46(5): 891-900. DOI:10.16420/j.issn.0513-353x.2018-0858
• Abstract ( 581 ) HTML ( 671 ) PDF (1582KB) ( 671 ) 　　　
• Capsicum annuum L.‘Niuneimu Huangshuai’used as experimental material，the possible mechanism of foliar-spraying 1-methylcyclopropene（1-MCP）alleviating the injury of pepper seedlings under high temperature stress was studied. The results showed that the growth of pepper seedlings was significantly suppressed by high temperature stress，and the heat injury index was reached up to 60.5. The biomass，root activity，chlorophyll content，net photosynthetic rate，leaf antioxidant enzymes activities，the contents of soluble protein and soluble sugar of pepper seedlings were significantly promoted by foliar-spraying 80 g · hm-2 1-MCP compared with the treatment of foliar-spraying water. Moreover，the accumulation of reactive oxygen species and cell membrane permeability of pepper seedlings treated with foliar-spraying 80 g · hm-2 1-MCP under high temperature were significantly decreased compared with the treatment of foliar-spraying water. In addition，the abscisic acid content and ethylene release rate in pepper leaves treated with 1-MCP under high temperature stress was decreased，on the contrary，fruit setting and yield per plant were effectively improved compared with the treatment of foliar-spraying water. In conclusion，the results indicated that foliar-applied suitable concentration of 1-MCP on pepper seedlings under high temperature stress could enhance photosynthesis rate and osmotic adjustment activity，inhibited the accumulation of reactive oxygen species，and regulate the hormone contents，as a result，improved the yield of peppers.
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• NO is Involved in ABA-regulated Senescence of Cut Roses by Maintaining Water Content and Increasing Antioxidant Enzyme Activities
• FANG Hua，WANG Chunlei，LIAO Weibiao*，ZHANG Jing，HUO Jianqiang，HUANG Dengjing，NIU Lijuan，and WANG Bo
• Acta Horticulturae Sinica. 2019, 46(5): 901-909. DOI:10.16420/j.issn.0513-353x.2018-0659
• Abstract ( 342 ) HTML ( 608 ) PDF (1853KB) ( 608 ) 　　　
• Cut roses（Rosa hybrida‘Tineke’）were used to investigate the effects of abscisic acid （ABA）and nitric oxide（NO）on cut flower senescence and the interaction between NO and ABA during postharvest freshness. The results show that 0.5 μmol · L-1 ABA significantly increased the vase life and flower diameter compared with distilled water（the control）. However，1.0 and 2.0 μmol · L-1 ABA significantly reduced flower diameter in comparison with the control. 150 μmol · L-1 NO donor SNP increased vase life by 70.7% compared with the control. NO synthesis inhibitor sodium tungstate significantly inhibited the promotive effects of ABA on vase life and flower diameter，showing that NO was required for ABA-regulated senescence of cut roses. Moreover，ABA kept the relative water content of cut rose leaves，while sodium tungstate inhibited the positive effects of ABA. Furthermore，ABA significantly increased the activities of superoxide dismutase，peroxidase and ascorbate peroxidase in cut rose leaves. However，the promotive effect of ABA on the activities of antioxidant enzymes was reversed by sodium tungstate，indicating that NO is involved in ABA-induced antioxidant capacity during postharvest freshness. Together，our results show that NO might be involved in ABA-delayed senescence of cut flowers by maintaining water content and increasing activities of antioxidant enzymes.
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• Cross Fertility of The Crosses Between Rhododendron Different Hybrids Groups
• XIE Weijia1,2，LI Shifeng1，QU Suping1，PENG Lvchun1，ZHANG Lu1，YANG Xiumei1，and WANG Jihua1,*
• Acta Horticulturae Sinica. 2019, 46(5): 910-922. DOI:10.16420/j.issn.0513-353x.2018-0394
• Abstract ( 374 ) HTML ( 646 ) PDF (5401KB) ( 646 ) 　　　
• In order to verify the hybrid incompatibilities among different hybrids groups belonging to Rhododendron Subgenus Hymenanthes，302 hand cross pollination treatments among 33 cultivars were conducted. According to a previous cultivar classification，all these hybrids can be divided into the Griffithianum hybrids group（Gr），Fortunei hybrids group（F），Gatawba hybrids group（Ga），Caucasicum hybrids group（C）and Degronianum hybrids group（D），respectively. The fruit set，seed set and seed germination rate were then statistically analyzed. Moreover，another types of cross pollinations including two hybrid groups as male and all these 5 different hybrids groups as female were conducted. The pollen germination rate，the pollen length/style length and the rate of the fertilized ovules in the crosses were observed by the fluorescence microscopy. The results showed that：（1）Fruit sets were varied when the same cultivar was used as the different parents. In 33 cultivars，11 cultivars were suitable as female and 5 cultivars were suitable as male，whereas 16 cultivars could be used as both female and male，however 1 cultivar‘Cosmopolitan’was not suitable as parents；With regards to the 5 hybrids groups，Gr was suitable as female，F was suitable as male，and Ga could be used as both，and the fertilization effect of C and D was related to its matching. The unilateral sterility，the bilateral fertility or sterility could be found among these different hybrids groups.（2）The order of the fruit set，seed set and the seed germination rate of the 5 hybrids groups as female parent were Ga > Gr > C > D > F，Ga > C > Gr > D > F，Ga > C > F > Gr > D，respectively；and the order of the fruit set, seed set and the seed germination rate of the 5 hybrids groups as male parent were F > Ga > Gr > D > C，F > Ga > D > C > Gr，F > Ga > Gr > C > D，and the order of the fruit set，seed set and the seed germination rate of the 5 hybrids groups as parent were Ga > F > Gr > D > C，Ga > F > D > C > Gr，F > Ga > C > Gr > D.（3）According to the pollen fluorescence microscopic observation，the pollen grains of all the tested crosses could germinate except the pollination treatment of D × F. However，the pollen tube length/style length of the cross combinations were different，and their fertilized ovule rate were low. In summary，there were obvious infertility phenomena among the different hybrids groups of Rhododendron Subgenus Hymenanthes，and the sterile types included no fruits，no seeds or no seed germination，and the pre-fertilization and post-fertilization barriers could contribute to these different types of incompatibilities.
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• Pathogenic Identification of Rhododendron Dieback and Investigation of Cultivar Resistance
• YANG Xiumei1，QU Suping1，ZHANG Baoqiong2，XU Feng1，and XIE Weijia1,*
• Acta Horticulturae Sinica. 2019, 46(5): 923-930. DOI:10.16420/j.issn.0513-353x.2018-0467
• Abstract ( 338 ) HTML ( 602 ) PDF (1792KB) ( 602 ) 　　　
• A new branch disease on Rhododendron was observed in a planting base in Jinning District，Kunming，Yunnan. The disease incidence was more than 20%. Disease symptoms included twig dieback and stem canker. Pathogens were isolated from the disease samples. The pathogenicity test，morphological and molecular identification were studied and cultivar resistance of Rhododendron were evaluated. The results showed that the mycelium was white initially and turned gray-black later. Conidia were one-celled，ellipsoidal to fusiform，with the length of 17.2 to 32.8 μm and the width of 4.7 to 7.8 μm. The internal transcribed spacer（ITS）region was amplified using the ITS1/ITS4 primer pair. BLAST analysis of the sequence showed 99% homology with the sequence of Neofusicoccum parvum. Based on the morphology and ITS sequence analysis，the pathogen was identified as N. parvum. The optimum temperature for mycelium growth was 25 ℃. The mycelial growth rate increased rapidly at pH 5–7，and the optimum pH value was 7. The utilization rates of sucrose and ammonium sulfate were the highest among all carbon and nitrogen sources，respectively. Different cultivars exhibited different disease resistances，including two immune cultivars，two highly resistant cultivars，three resistant cultivars，three moderately susceptible cultivars，four susceptible cultivars and four highly susceptible cultivars.
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Research Notes

• Study on Differences of Coloration Process in Different Parts of Ethephon- degreened Mandarin Fruit
• DENG Lili1,2，YUAN Ziyi1,3，YAO Shixiang1,2，and ZENG Kaifang1,2,*
• Acta Horticulturae Sinica. 2019, 46(5): 931-938. DOI:10.16420/j.issn.0513-353x.2018-0720
• Abstract ( 346 ) HTML ( 483 ) PDF (1945KB) ( 483 ) 　　　
• The gradient coloration of ethylene-degreened mandarin fruit was studied. The results indicated that the coloration process of stem end position of the peel was faster than the equator position during the degreening process. The difference of chlorophyll content and carotenoid content of these two positions could well explain this phenomenon. Further studies indicated that the degradation of chlorophyll a and chlorophyll b in the stem end position of ethylene-degreened mandarin fruit was faster than that in the equator position，more orange-colored carotenoids（mainly β-cryptoxanthin）were synthesized in the stem end position of ethylene-degreened mandarin fruit，while more yellow-colored carotenoids（mainly lutein）were synthesized in the equator position. The different expression levels of some regulatory genes in chlorophyll and carotenoid metabolism（including CitChlase，CitNYC，CitPDS，CitCHYB，CitNCED1 and CitNCED2）could explain the pigment changes of these positions to some extent.
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• Identification and Expression Analysis of WRKY Transcription Factors in Eriobotrya japonica
• LI Xiaoying，XU Hongxia，and CHEN Junwei*
• Acta Horticulturae Sinica. 2019, 46(5): 939-954. DOI:10.16420/j.issn.0513-353x.2018-0671
• Abstract ( 406 ) HTML ( 1639 ) PDF (3958KB) ( 1639 ) 　　　
• In this study，the data of loquat transcriptome were used to identify and characterize loquat WRKY transcription factors. The results show that this study isolated 33 sequences with typical WRKY structure domains，and the CDS length was distributed in 492–2 040 bp，named EjWRKY01–EjWRKY33. The analysis results of group identification and evolutionary tree show that the loquat WRKY TF can be divided into three categories，including classⅠ，Ⅱ and Ⅲ，the number of each class was 6，22 and 5，respectively. Class Ⅱ is further divided into five subgroups（a–e）. The genomic DNA sequence of EjWRKY TF is from 895 to 3 873 bp with 1–5 introns，whose encoded protein was in the range of 163–679 amino acids. The prediction results of cis-acting elements of WRKY promoter show that most WRKY promoter sequences have typical TATA and CAAT elements. The phylogenetic analysis of WRKY TF among Arabidopsis and loquat showed that many WRKY proteins clustered together，displaying close phylogenetic relationships，which indicated that although there were differences among the gene sequences of different species，the functional features of the WRKY proteins in regulating biotic and abiotic stress responses，metabolic regulation，signal transduction，growth and development and morphogenesis were similar. Furthermore，the RT-PCR results showed that most of EjWRKY genes were expressed in root，stem，leaf，flower and fruit of loquat，but the relative expression levels were different，which suggested that WRKY family genes may have different functions in the growth and development of loquat.
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• Differential Expression of Three R2R3-MYBs Genes Regulating Anthocyanin Pigmentation Patterns in Lilium spp.
• CAO Yuwei1，XU Leifeng1，YANG Panpan1，XU Hua1，HE Guoren1，TANG Yuchao1，REN Junfang2，and MING Jun1,*
• Acta Horticulturae Sinica. 2019, 46(5): 955-963. DOI:10.16420/j.issn.0513-353x.2018-0241
• Abstract ( 321 ) HTML ( 773 ) PDF (4037KB) ( 773 ) 　　　
• Anthocyanin accumulation in different parts of tepal developed various pigmentation patterns，but the expression patterns of R2R3-MYBs regulating various anthocyanin pigmentation patterns in Lilium spp. are not well understood. In this study，expression patterns of LhMYB12，LhMYB6 and LrMYB15 genes regulating various anthocyanin pigmentation patterns were performed in seven different pigmentation patterns of materials[Asiatic hybrids，LA（Lilium longiflorum × Asiatic hybrids）and wild species]. LhMYB12 and LhMYB6，cloned full-length cDNA and analyzed gene sequences，were considered to be regulated gene related to anthocyanin pigmentation patterns. The study showed LhMYB12 was expressed in linear spots at edge of tepals and splatter spots in Asiatic hybrids. But LhMYB12 and LhMYB6 were expressed in linear spots at edge of tepals and splatter spots in LA hybrids. And only LhMYB12 was expressed in anthocyanin pigmentation patterns of wild species（L. rosthornii，L. henryi and L. martagon）. However，anthocyanin pigmentation patterns of these parameters were not observed in LrMYB15. The full-length of LhMYB12 and LhMYB6 was 763 and 797 bp containing open reading frame of 744 and 705 bp，which encoded 247 and 234 amino acids respectively. They were homologous sequence with published LhMYB12，LhSorMYB12 and LhMYB6，sharing 78% to 88% similarity with them. The results indicated that LhMYB12 played an important role in the regulation of anthocyanin pigmentation patterns in hybrids and wild species widely. Moreover，LhMYB12 and LhMYB6 regulated anthocyanin in LA hybrids. This study revealed that the expression of R2R3-MYBs was involved in regulating various anthocyanin pigmentation patterns in different species.
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• The Photosynthetic Characteristics of Phoebe zhennan f. elliptical and P. zhennan f. oblong
• FANG Xia1，BAI Zhiliang1，ZHOU Shengcai2，ZHANG Lizhen2，WU Qiang 2，ZHANG Junhong1，and TONG Zaikang1,*
• Acta Horticulturae Sinica. 2019, 46(5): 964-974. DOI:10.16420/j.issn.0513-353x.2018-0551
• Abstract ( 493 ) HTML ( 570 ) PDF (924KB) ( 570 ) 　　　
• Two-year-old Phoebe zhennan f. elliptical and P. zhennan f. oblong were used to study the photosynthetic pigment content，light response curves，gas exchange，photosynthetic characteristics，and chlorophyll fluorescence parameters in summer. We found that the ratios of chlorophyll a to chlorophyll b （Chl. a/b）in P. zhennan f. elliptical and P. zhennan f. oblong were 2.617 and 2.651，respectively. Therefore，both are shade-requiring plants. The minimal fluorescence（Fo），the actual photochemical efficiency of PSⅡ（ΦPSⅡ），photochemical quenching（qP），and maximum fluorescence（Fm）of P. zhennan f. oblong were higher than those of P. zhennan f. elliptical，although there were no significant differences in the maximum photochemical quantum yield（Fv/Fm）. The light saturation point（LSP）of P. zhennan f. elliptical was higher than that of P. zhennan f. oblong（506.00 vs. 431.00 μmol · m-2 · s-1）. Therefore，P. zhennan f. elliptical has stronger light-utilization ability. However，the light compensation point（LCP）of P. zhennan f. oblong was lower than that of P. zhennan f. elliptical（16.20 vs. 29.25 μmol · m-2 · s-1），which suggests that P. zhennan f. oblong has greater ability to use weak light. The diurnal changes in the net photosynthetic rate（Pn）in summer had a double peak，with the major peak at 10:00 am. The Pn was higher in P. zhennan f. elliptical than in P. zhennan f. oblong（7.52 vs. 5.41 μmol · m-2 · s-1）. The two types of P. zhennan showed a“light lunch break”，which is mainly caused by non-stomatal limitations. In brief，Chl.a/b and LCP were important indicators for measuring shade tolerance. Both types of P. zhennan were shade-requiring plants，although P. zhennan f. oblong had stronger shade tolerance，while P. zhennan f. elliptical can adapt to a wider range of light.
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Review

• Light Regulation of Chlorophyll Biosynthesis in Plants
• WANG Feng*，YAN Jiarong，CHEN Xueyu，JIANG Chenghao，MENG Sida，LIU Yufeng，XU Tao，QI Mingfang，and LI Tianlai*
• Acta Horticulturae Sinica. 2019, 46(5): 975-994. DOI:10.16420/j.issn.0513-353x.2018-0799
• Abstract ( 373 ) HTML ( 1835 ) PDF (3381KB) ( 1835 ) 　　　
• This review summarized the studies concerning with the effects of light signaling（such as light intensity，light quality，photoperiod and circadian rhythm）on Chl accumulation and its biosynthesis-related genes. The regulation mechanism of Chl biosynthesis-related genes by transcription factors in the light signaling pathway and histone epigenetic modifications were emphasized，which may help us to explore effective pathways and target molecules in light-regulation of Chl biosynthesis，and promote Chl accumulation via genetic engineering and environmental regulation.
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• Research Progress on Omics and Genetic Determinism of Blooming Behavior and Flower Scent in Rose
• LI Shubin1,2，WANG Weijia2，WU Gaoqiong2，YU Chunxia2，TANG Kaixue2，WANG Siqing1,*，and DAI Silan1,*
• Acta Horticulturae Sinica. 2019, 46(5): 995-1010. DOI:10.16420/j.issn.0513-353x.2018-1066
• Abstract ( 495 ) HTML ( 1197 ) PDF (815KB) ( 1197 ) 　　　
• This paper reviews the important research progress on nuclear genome，chloroplast genome，transcriptome and epigenomics of Rosa sp.，combining with the recent study findings of the genetic determinism of continuous flowering and flower scent. In order to provide theoretical reference for answering the important biological questions of roses and the creation of new genetic resources，several key scientific questions are discussed and the prospect of the future research is proposed.
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New Cultivars

• A New Late Ripening Apple Cultivar‘Qincui’
• ZOU Yangjun1，MA Fengwang1,*，FU Xuanchang1，LI Cuiying1，AN Guiyang1，LI Mingjun1，LI Chao1，and DANG Zhiming2
• Acta Horticulturae Sinica. 2019, 46(5): 1011-1012. DOI:10.16420/j.issn.0513-353x.2018-0368
• Abstract ( 963 ) HTML ( 507 ) PDF (1078KB) ( 507 ) 　　　
• ‘Qincui’is a new late-ripening apple cultivar selected from the progenies of ‘Nagano Fuji 2’בHoney Crisp’. It produces cylinder-shaped fruits with average fruit weight of 268 g. Its fruit skin is in fully red color with dark red stripes，glabrous cover and small dots. The flesh is in yellowish-white color and in good balance of sugar and acids.‘Qincui’is a desert apple cultivar with crispy，juicy，aromatic characteristics.‘Qincui’contains 14.8% of the total soluble solids content，0.26% of the total titratable acid，195.8 mg · kg-1 of vitamin C，and its firmness is 6.70 kg · cm-2. The fruit development period is about 170 d，no pre-harvest drop phenomenon，ripening in early October at Luochuan County，Shaanxi Province. The main characteristics are early-bearing，high and stable yield.
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• A New Early Ripening Sweet Cherry Cultivar‘Zaomilu’
• CHENG Hehe，CHEN Long，LI Yusheng，ZHAO Yanhua，WU Yongjie，LI Yougang，and WU Yaqin*
• Acta Horticulturae Sinica. 2019, 46(5): 1013-1014. DOI:10.16420/j.issn.0513-353x.2019-0058
• Abstract ( 695 ) HTML ( 444 ) PDF (1275KB) ( 444 ) 　　　
• ‘Zaomilu’is a new early ripening sweet cherry cultivar. It is obtained from naturally pollinated seeds of‘Hongdeng’ through embryo rescue. The fruit development period is 40–42 days. The fruit is heart shape，with deep red skin. The average fruit weight is 8.5 g，and the biggest one is 11.0 g. The flesh is red，juicy and sweet. It is delicious with 18.0% soluble solids content. It has high yield，with strong resistance to cold and disease.
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• A New Walnut Cultivar‘Hongyun’
• XIAO Liangjun1，NING Delu1,*，MA Ting1，and YANG Changwu2
• Acta Horticulturae Sinica. 2019, 46(5): 1015-1016. DOI:10.16420/j.issn.0513-353x.2018-0352
• Abstract ( 249 ) HTML ( 496 ) PDF (1610KB) ( 496 ) 　　　
• ‘Hongyun’walnut was selected and bred from individual variation in walnut nursery in Jingdong County，Yunnan Province. It has red tender leaf，triangular female flower bud，reddish brown scales and red stigma. It has good ornamental effect and high yield. This cultivar has high cultural value and ornamental value.
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• A New Salvia splendens Cultivar‘Feifan’with Orange-red Flower
• LI Chunnan，FU Qiaojuan*，SHEN Guozheng，CHEN Yi，and CHEN Wenyue
• Acta Horticulturae Sinica. 2019, 46(5): 1017-1018. DOI:10.16420/j.issn.0513-353x.2018-0350
• Abstract ( 225 ) HTML ( 372 ) PDF (1307KB) ( 372 ) 　　　
• ‘Feifan’is a new Salvia splendens cultivar，derived from chemical mutagenesis combined with system selection.‘Feifan’belongs to a dwarf and erect type with strong branching character and light green leaves. The average plant height and crown diameter is 21.2 cm and 21.9 cm in full-blossom period，respectively. It has high ornamental value in terms of orange-red flower，long inflorescence and long ornamental time of 62.4 d. Meanwhile，this cultivar is highly resistant to heat stress and suitable for cultivation in the region of Zhejiang Province or other area with the similar climate condition.
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