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    A New Chaenomeles Crabapple Cultivar‘Caiyu’
    A New Chaenomeles Crabapple Cultivar‘Caiyu’
    Acta Horticulturae Sinica    2021, 48 (S2): 2975-2976.   DOI: 10.16420/j.issn.0513-353x.2021-0905
    Abstract1982)      PDF (1323KB)(37)      
    ‘Caiyu’is a new Chaenomeles crabapple cultivar which has been selected from the seedlings of Chaenomeles‘Toyonisiki’. The cultivar has one trunk,and plant architecture is half-spread. The young leaves are greenyellow,the edge is chocolate,with lappaceous serrations;the old leaves become dark green,and the edge is sharply serrated. The flowers are usually in groups of three,semidouble petals. The colors of petal are light red or green-and-white at the initial stage,all of them turn pink at the mid to late stage. Blooming period lasts one month. The pistil is generally impotent,so it bear few fruit. Flower characters are stable,the cultivar has strong resistance,high grafting survival rate,fast-growing and high ornamental value.
    A New Crabapple Cultivar‘Menghuijuan’
    CHEN Li, ZHOU Jinchuan, HAN Qingdian, WANG Xiangbo, GUAN Qide, and CHEN Zhiqun,
    Acta Horticulturae Sinica    2021, 48 (S2): 2981-2982.   DOI: 10.16420/j.issn.0513-353x.2021-1054
    Abstract1049)      PDF (1257KB)(28)      
    The new cultivar‘Menghuijuan’with red semidouble flower is selected from the progeny of Chaenomeles speciosa(Sweet)Nakai. The flower is large in diameter. The cultivar likes acid soil. It is resistant to drought and barren. The plant is easy to manage,which has unique flower color. The cultivar is suitable for bonsai production,courtyard and road greening,etc.
    A New Watermelon Cultivar‘Jingmei 10K’
    ZHANG Haiying, GONG Guoyi, GUO Shaogui, REN Yi, ZHANG Jie, LI Maoying, XU Yong
    Acta Horticulturae Sinica    2021, 48 (7): 1435-1436.   DOI: 10.16420/j.issn.0513-353x.2021-0229
    Abstract680)   HTML14)    PDF (1227KB)(107)      

    ‘Jingmei 10K’is a new mid-maturing watermelon cultivar. The fruit is short oval with heavy wax,the fruit index is 1.2. The fruit has durable rind for transportation,which is green with narrow dark green strips,about 1.2 cm thick. The fruit is uniform in shape with high commodity rate. The flesh is bright red with 50.5 mg · kg-1 FW lycopene content,and its center soluble solids content is 13%. It is crisp with good taste and less watery flesh,and it can turn color fast. The total growing period is about 95 d and the fruit development period is about 35 d. The average fruit weight is 10 kg and the yield is about 75 000 kg · hm-2. It is suitable for protected and open field cultivation in spring.

    Cloning and Functional Analysis of Squalene Synthase Gene in Citrus
    WANG Fusheng, LIU Xiaona, XU Yuanyuan, LIU Xiaofeng, ZHU Shiping, ZHAO Xiaochun
    Acta Horticulturae Sinica    2021, 48 (9): 1641-1652.   DOI: 10.16420/j.issn.0513-353x.2021-0580
    Abstract675)   HTML58)    PDF (1598KB)(1492)      

    A squalene synthase(SQS)gene was isolated from 18 citrus accessions,and its sequence and expression characteristics were analyzed. The roles in the biosynthesis of limonoids were identified by genetic transformation. The results showed that the full length of SQS ORF(open reading frame)in citrus is 1 242 bp,coding 413 amino acids except in the accessions of Rongan Kumquat(Fortunella classifalia)and Xiaoguo Kumquat(F. margarita). Clustal analysis showed that the deduced amino acids of SQS shared from 97.1% to 100% homology among the 18 citrus accessions. SQS in Xiaoguo kumquat,Rongan kumquat,and No.4 Ichang Papeda(Citrus ichangensis)shared a G/C nonsynonymous mutation at the fourteenth nucleotide of CDS region. Phylogenetic analysis result of SQS proteins showed that the SQS of those accessions clustered together. qRT-PCR analysis showed that the highest expression of SQS was observed in flower,followed by that in stem,root,leaf,and young fruit. The expression level of SQS gene is positively correlated with the limonoids contents in seeds of Guanxi Mi You(C. grandis)variety at different development stages. Four positive SQS interference transgenic citrus plants(SiN-1-SiN-4)were obtained via citrus genetic transformation. The expression levels of SQS gene in four transgenic lines were 61.00% to 79.00% of the control plants. Obvious deduction on limonin content was observed in all the four transgenic lines(about 35.83% to 81.56% of the control plants). The contents of nomilin in SiN-1 and SiN-2 lines were decreased to 80.11% and 94.94% of the control,respectively. However,the nomilin content increased by 52.76% and 35.30% in SiN-3 and SiN-4 lines,respectively. The expression levels of genes belonging to oxidosqualene cyclase(OSC)superfamily involved in triterpenoids and sterol biosynthesis were down-regulated in SQS interference transgenic citrus plants. This may due to the reduced supply of precursor for triterpenoids and sterol biosynthesis. This study indicated that SQS gene contributed greatly to the production of limonoids in citrus.

    A New Melon Cultivar‘Huangmapao’
    MA Zongxin, CHEN Jinliang, JIN Yong, XU Gongxue, and WANG Xinmeng
    Acta Horticulturae Sinica    2021, 48 (S2): 2875-2876.   DOI: 10.16420/j.issn.0513-353x.2020-0646
    Abstract641)      PDF (1526KB)(14)      
    The new cultivar‘Huangmapao’of Cucumis melo L. var. agrestis Naud. was selected from the offspring of hybrid with‘Huangma 1’as female parent and‘Dongfangmi 1’as male parent. The fruit is oval,the longitudinal diameter is 5.87 cm,the transverse diameter is 4.74 cm. The skin is yellow with an average weight of 45 g. The average yield was 23 250 kg • hm-2,and the high yield was 45 450 kg • hm-2,which was 41.32% higher than that of Cucumis melo L. var. agrestis Naud. It is moderate resistant to powdery mildew,downy mildew,and Fusarium wilt. The cultivar is mainly used for seed oil and picking ornamental.
    Cloning and Functional Characterization of Chalcone Synthase Genes(CmCHS)from Clivia miniata
    LIU Yue, LI Yueqing, MENG Xiangyu, HUANG Jing, TANG Hao, LI Yuanheng, GAO Xiang, ZHAO Chunli
    Acta Horticulturae Sinica    2021, 48 (10): 1847-1858.   DOI: 10.16420/j.issn.0513-353x.2021-0090
    Abstract617)   HTML60)    PDF (4349KB)(920)      

    In order to investigate the structure and function of Chalcone Synthase from Clivia miniata,members of CHS gene family were screened and identified based on the previously constructed transcriptome database. The results showed that four CmCHSsCmCHS1,CmCHS2,CmCHS3 and CmCHS4)genes were cloned in C. miniata. The open reading frames of the four CmCHSs were 1 173,1 170,1 173 and 1 173 bp and encoding 390,389,390,390 respectively. Amino acid sequence that CmCHSs had typical the conserved domains. Phylogenetic tree analysis showed that the four CmCHS genes clustered with the bona-fide CHSs from other plants and belonged to type Ⅲ polyketide synthase(PKS)super family. The results of subcellular localization showed that they were localized in the cytoplasm and nucleus. Gene expressionanalysis showed CmCHS1 and CmCHS2 were highly expressed at the late stage of flower development process,and the transcripts of CmCHS1,CmCHS2 and CmCHS3 were confirmed to the extensively detected in pigmented leaves and red fruit peels. In contrast,the expression level of CmCHS4 gene was relatively low. In order to firmly verified the roles of CmCHSs in the biosynthesis of anthocyanins,prokaryotic expression vectors,pET-32-CmCHS,were constructed and recombinant proteins were prepared and purified,which were subjected to in vitro enzyme activity analysis. Results showed that the four CmCHS recombinant proteins could catalyze coumarinyl-CoA and malonyl-Coenzyme A into naringenin chalcone. This study explored the bioinformatics analysis,gene expression analysis,and functional analysis of CmCHS genes,and laid a theoretical foundation for the genetic transformation and flower color improvement of C. miniata.

    Cloning and Expression Analysis of the Cytokinin Response Regulator VlRR5 in Kyoho Grapevine
    BIAN Lu, GUO Dalong, YU Keke, WEI Tonglu, PEI Maosong, LIU Hainan, YU Yihe
    Acta Horticulturae Sinica    2021, 48 (8): 1437-1445.   DOI: 10.16420/j.issn.0513-353x.2020-0668
    Abstract579)   HTML61)    PDF (1742KB)(429)      

    There are three fruit-dropping peaks in grape growth and development. Grape fruit-dropping phenomenon is more serious in Kyoho grapevine. In this study,a cytokinin response regulator VlRR5 was cloned from Kyoho grapevine,which has a phosphoric acid receptor domain(REC)and a MYB-like DNA binding domain. Sequence analysis revealed that cDNA of VlRR5 was 2 597 bp in length,encoding 693 amino acids,and located on chromosome 4 of grape. Subcellular localization assay showed that VlRR5 was localized in the nucleus. The yeast transformed into pGBKT7-VlRR5 could grow normally and turn blue on SD/-Trp/-Ade/-His/+X-α-Gal deficient medium,which proved that VlRR5 was a transcription factor with transcriptional activation activity. By quantitative real-time PCR analysis,VlRR5 was characterized by tissue specific expression and showed high expression level in leaf and stem,which was increased and then decreased in the development stage of young fruit. The expression level increased after treatment with exogenous cytokinin,and decreased after treatment with the cytokinin synthesis inhibitor lovastatin. These results indicated that VlRR5 can respond to cytokinin and plays an important role in participating in cytokinin to improve the fruiting rate of grape.

    The Impact of Tepal Structure and Pigment Composition on the Flower Colour of Lily
    WANG Qing, LÜ Tong, LÜ Yingmin
    Acta Horticulturae Sinica    2021, 48 (10): 1873-1884.   DOI: 10.16420/j.issn.0513-353x.2021-0519
    Abstract548)   HTML21)    PDF (10452KB)(597)      

    Twenty-seven lily cultivars of seven colour group were used to analyze the lily tepal structure,the pigments exist in upper and lower epidermis of lily tepals. The upper and lower epidermal cells are irregular rectangular in most of the lily cultivars while some epidermal cells present closely regular polygon that contain anthocyanin. At the same time,tepal spots contained anthocyanins. Sixty-one lily cultivars and two wild species of seven colour group were used to analyze the tepal pigment composition,twenty-three kinds of flavonoid compounds,one kind of anthocyanin ( cyaniding-3-O- rutinoside ) and ten carotenoids ( 9Z-violaxanthin,antheraxanthin,9Z-antheraxanthin,mutatoxanthin,capsanthin,lutein,zeaxanthin,β-cryptoxanthin,β-carotene,and 9Z-β-carotene ) were identified by HPLC-QTOF-MS from lily tepal. The lily tepal all contained flavonoids. White tepal mainly contained flavonoids and some cultivars had a tiny amount of carotenoids. Red tepal contained anthocyanins,carotenoids and flavonoids while carotenoids and anthocyanins were the main pigment,flavonoids served as co-pigment. Purple-red and pink tepal contained anthocyanins and flavonoids while yellow and orange tepal mainly contained carotenoids.

    A New Late-maturing Litchi Cultivar‘Guishuang’
    YE Xiangyang, WU Xiaofang, LI Hua, LIN Jinhe, MA Ke, YE Hanjiang, LI Jianguo, YE Zhaoxiong, and WANG Zehuai
    Acta Horticulturae Sinica    2021, 48 (S2): 2817-2818.   DOI: 10.16420/j.issn.0513-353x.2021-0314
    Abstract539)      PDF (894KB)(19)      
    ‘Guishuang’is a new litchi cultivar selected from seedlings in Guangdong. The fruit is crooked heart-shaped with dark red pericarp. The flesh tastes crispy. The average weight of single fruit was 31.7 g. The flesh recovery,seed-abortion rate and soluble solids content were 78.7%,86.7% and 17.1%–18.6%,respectively. The maturity period is early July,with outstanding advantages such as large fruit,late maturity,high quality,easy flowering,and high and stable yield. The average yield per plant in the fourth and fifth year of high-grafted trees is 17.3 and 24.3 kg,respectively.
    Transcriptome Analysis of the Molecular Mechanism of Saline-alkali Stress Response in Malus halliana Leaves
    ZHANG Rui, ZHANG Xiayi, ZHAO Ting, WANG Shuangcheng, ZHANG Zhongxing, LIU Bo, ZHANG De, WANG Yanxiu
    Acta Horticulturae Sinica    2022, 49 (2): 237-251.   DOI: 10.16420/j.issn.0513-353x.2021-0077
    Abstract473)   HTML90)    PDF (3536KB)(457)      

    Malus halliana is a highly saline-alkali-resistant apple rootstock in north-western China. The genes and main pathways which respond to saline-alkali stress were identified by RNA-Seq. This study revealed the mechanism of the response to salt damage and provided theoretical basis for the salt tolerance mechanism of apple rootstocks. Normal water(Hoagland nutrient solution)(Control)supply and mixed saline-alkali stress(Hoagland nutrient solution + 100 mmol · L-1 NaCl + NaHCO3)(Treatment)were set up to screen the saline-alkali resistance of each treatment in the growth period. These two samples before and after saline-alkali treatment were analyzed by RNA-seq. The function and pathway enrichment of differentially expressed genes(DEG)were also performed by GO and KEGG analysis. Twenty DEG were randomly selected for further qRT-PCR analysis to verify the RNA-seq data. A total of 16 246 DEGs were determined,7 268 genes were up-regulated and 8 978 genes down-regulated under saline-alkali stress. GO analysis fund that the DEGs were considerably differenct in the biological processes,cell components and molecular functions. KEGG analysis indicated that most enriched saline-alkali-responsive genes were mainly involved in signal transduction,carbon metabolism,biosynthesis of amino acids,and other secondary metabolites. DEG mainly focused on calcium signaling pathway,plant hormone signal transduction,phenylalanine metabolism,and carotenoid biosynthesis. qRT-PCR detection results of 20 DEG expression patterns were similar to those of RNA-seq. Among them,aspartate aminotransferase(GOT1),monodehydroascorbate reductase(NADH),chalcone isomerase(CHI,E5.5.1.6),β-carotene 3-hydroxylase(CrtZ)genes were highly expressed during saline-alkali stress. The results indicated that they might play a role in the leaf response to saline-alkali stress. M. halliana is mainly regulated by calcium signal pathway,plant hormone signal transduction,biosynthesis of amino acids, carotenoid biosynthesis and other secondary metabolites to respond to saline-alkali stress.

    A New Chaenomeles Crabapple Cultivar‘Huatiannü’
    ZHANG Haijuan, GUAN Qide, ZHOU Jinchuan, and GAO Yueheng
    Acta Horticulturae Sinica    2021, 48 (S2): 2983-2984.   DOI: 10.16420/j.issn.0513-353x.2021-0889
    Abstract423)      PDF (1011KB)(22)      
    ‘Huatiannü’is a Chaenomeles crabapple cultivar with semi-double flower. The flower diameter is 4–5 cm,and it has different colors including red and white,some white petals have red patches or streaks inlay.
    Review of the Role of Melatonin in Fruit Development and Postharvest Preservation
    ZHAO Yuqing, CHEN Tao, YUAN Ming
    Acta Horticulturae Sinica    2021, 48 (6): 1233-1249.   DOI: 10.16420/j.issn.0513-353x.2020-0496
    Abstract422)   HTML21)    PDF (846KB)(223)      

    Melatonin is a plant growth regulator and bio-stimulator,which can regulate plant growth and development,and improve plant stress tolerance. In recent years,the roles of melatonin in fruit development regulation and postharvest preservation have been hot researches. This paper summarizes the content and distribution of melatonin in different fruit. The physiological functions and mechanisms of melatonin in regulating fruit growth and development,promoting postharvest fruit ripening and delaying fruit senescence are emphasized. It points out the shortcomings in the present studies and puts forward suggestion for the future research direction of melatonin,and provides reference for melatonin to be widely used in the regulation of fruit development and preservation.

    Anatomical Observation on Clove Formation and Development of Garlic
    LIU Zhuoya, LIU Xiuhui, JIA Huixia, SONG Jiangping, LI Xixiang, ZHAO Danqi, ZHANG Xiaohui, YANG Wenlong, WANG Haiping
    Acta Horticulturae Sinica    2021, 48 (7): 1409-1417.   DOI: 10.16420/j.issn.0513-353x.2021-0526
    Abstract411)   HTML14)    PDF (4962KB)(148)      

    In the present study,the process of garlic(Allium sativum)clove development was observed and analyzed through freehand anatomy and paraffin embedded. The morphological observation showed that there were three stages,including the pre-differentiation stage,differentiationstage and expansion stage for clove development before mature. At the pre-differentiation stage,the leaf primordia with typical tunica-corpus structure was formed. At the differentiation stage,small clove formed. The location of small clove formation was related to the location of meristematic cell mass. The internal growth points of the formed scale clove continued to differentiate with the accumulation of clove material. At the expansion stage,the chromosomes in the meristematic nuclei were active,starch grains were accumulated in the meristematic cell mass and the vessels had developed well in xylem. To observe the tissue histochemical changes,PAS staining was carried out on the sections from different parts of the clove at the differentiation stage. The content of sugar granules was rich,the cytoplasm was dense and the staining was dark. The concentration gradient of sugar granules existed between the meristematic cells and their surrounding cells.

    A New Double-harvest Water Bamboo Cultivar‘Zhejiao 8'
    ZHANG Shangfa, CHEN Keke, ZHENG Zhaisheng, YANG Mengfei, LI Yipeng, WANG Lingyun
    Acta Horticulturae Sinica    2021, 48 (6): 1271-1272.   DOI: 10.16420/j.issn.0513-353x.2020-0519
    Abstract408)   HTML12)    PDF (1081KB)(63)      

    ‘Zhejiao 8',a new early maturing double-harvest water bamboo cultivar developed by systematic selection from‘Suozijiao'mutants after 10 years,has compact plant type and medium growth vigor. The harvest period of‘Zhejiao 8'is 5-6 days earlier than that of‘Suozijiao'in fall. Gross harvested weight of‘Zhejiao 8'in fall is 107.8 g per each,net weight is 70.2 g per each,and the average yield is 17 910 kg · hm-2. The harvest period of‘Zhejiao 8'is 8-10 days earlier than that of ‘Suozijiao'in summer. Gross harvested weight of‘Zhejiao 8'in summer is 123.7 g per each,the net weight is 85.1 g per each,and the average yield is 34 170 kg · hm-2. The succulent stem has 3-5 joints and the bud is white. It has glossy surface,fine and tender quality. The cultivar was suitable for planted in Zhejiang Province.

    QTL Mapping of Bolting and Flowering Traits Based on High Density Genetic Map of Radish
    GAN Caixia, CUI Lei, PANG Wenxing, WANG Aihua, YU Xiaoqing, DENG Xiaohui, SONG Liping, PIAO Zhongyun
    Acta Horticulturae Sinica    2021, 48 (7): 1273-1281.   DOI: 10.16420/j.issn.0513-353x.2021-0201
    Abstract402)   HTML53)    PDF (1459KB)(305)      

    The late-bolting genes in radish were localized,and the candidate genes regulating flowering were explored. The main results are listed below:a high-density genetic linkage map was constructed and two QTL loci related to flowering and bolting were detected. Based on radish gene annotation and gene sequence alignment analysis,we detected five genes with the sequence variation between the parental lines,indicated those genes associated with bolting and flowering in radish. However,the detailed functions of the candidate gene during the radish bolting and flowering need further studies.

    Anatomical Observation on the Tortuousness of Ziziphus jujuba var. tortuosa Branches
    GUO Xuemin, WANG Xinrui, WANG Yingying, LI Zheng, MIAO Ningning, WANG Zhaojun
    Acta Horticulturae Sinica    2021, 48 (9): 1653-1664.   DOI: 10.16420/j.issn.0513-353x.2020-0561
    Abstract395)   HTML33)    PDF (8086KB)(211)      

    Taking the twisted tortuous branch segment and twisted straight branch segment of annual branches in Ziziphus jujuba Mill. var. tortuosa as experimental materials,the morphological,anatomical and vessel characteristics of its branches were observed and compared by xylotomy and wood segregation techniques. The differences of anatomical structures between twisted tortuous branch segment and twisted straight branch segment were mainly manifested in the number,shape and distribution of abnormal secondary structures. Compared with the twisted straight branch segment,the number of auxillary bundles in twisted tortuous branch segments was more,and there were three auxillary bundles adjacent to each other,which were relatively concentrated in the inner bend of the segments;The number of interxylary phloem was about the same as that of the twisted straight branch segment,and its end expanded,which was different from the slightly curved elliptic columnar shape of the twisted straight branch segment,and relatively concentrated in the outer bend of the segments;The number of medullary vascular bundles was slightly reduced. At the cellular level,the vessel elements at the inner and outer bends of the twisted tortuous branch segments of the variety were all reticulate vessels with single perforation and various shapes. Among them,the number of vessel elements with tails at both ends and sloped at both ends at the inner bend were 28.0% and 20.2% less than those at the outer bend,respectively. The number of vessels without tails at either ends,sloped at one end and horizontal at both ends were 17.9%,375.0% and 200.0% more,respectively. The number of vessels with one tail at one end was the same. The end wall slope of end wall was 10.1% larger than that at the outer bend,and the length of vessel element was 16.4% shorter than that at the outer bend,while the diameter was 18.6% smaller than that at the outer bend. The hypothesis of “abnormal structure-spatial difference-coordination”was put forward. The tortuous branch traits of Z. jujuba var. tortuosa may be the result of the unbalanced growth rates and forces at different locations of the branches caused by the spatial difference and coordination of the number,the mechanical tension,the transport and utilization of the assimilated products of the three abnormal secondary structures,namely the auxillary bundle,interxylary phloem and medullary bundle.

    A New Chaenomeles Crabapple Cultivar‘Zui Xishi’
    ZHOU Jinchuan, GUAN Qide, GUAN Xueying, ZHAO Yuhan, ZHANG Haijuan, and WANG Xiangbo
    Acta Horticulturae Sinica    2021, 48 (S2): 2977-2978.   DOI: 10.16420/j.issn.0513-353x.2021-0925
    Abstract394)      PDF (1164KB)(14)      
    The new Chaenomeles crabapple cultivar‘Zui Xishi’was derived from seedling in Qian Zhangzhuang Nursery in Tanghe Town,Linyi City. The flower diameter is medium. The outside petals is red or pink while the inside petals is greenish white at first,then they turn pink. It bloomed late,amost all the pistils could not development. It has unique color,fast-growing,ornamental value.
    Cloning and Functional Analysis of MdWRKY74 in Apple
    XIANG Li, ZHAO Lei, WANG Mei, LÜ Yi, WANG Yanfang, SHEN Xiang, CHEN Xuesen, YIN Chengmiao, MAO Zhiquan
    Acta Horticulturae Sinica    2022, 49 (3): 482-492.   DOI: 10.16420/j.issn.0513-353x.2021-0244
    Abstract382)   HTML37)    PDF (1537KB)(384)      

    In this study,a WRKY transcription factor gene,named MdWRKY74(XM_029090147.1)was obtained from apple rootstock M9T337(Malling 9 NAKBT337). The open reading frame of MdWRKY74 was 939 bp,which encoded 312 amino acids,and contained a typical WRKY domain. Amino acid sequence alignment and phylogenetic tree analysis showed that MdWRKY74 had the highest homology with Pyrus bretschneideri WRKY74. Subcellular localization assays showed that MdWRKY74 was located in the nucleus. Quantitative real-time PCR analysis showed that MdWRKY74 was expressed in different apple tissues. Overexpression of MdWRKY74 in Arabidopsis could improve the salt resistance of plants,and promote the expression of SOS1 and NHX1. The results showed that MdWRKY74 can be induced by salt stress,so it may participate in the regulation of salt resistance in apple.

    Leaf Cytological Characteristics and Resistance Comparison of Four Citrus Rootstocks Under Drought Stress
    ZHONG Zaofa, ZHANG Lijuan, GAO Sisi, PENG Ting
    Acta Horticulturae Sinica    2021, 48 (8): 1579-1588.   DOI: 10.16420/j.issn.0513-353x.2020-0502
    Abstract367)   HTML43)    PDF (2650KB)(303)      

    Mature leaves from two-year-old Sanhu red tangerine(Citrus reticulata Blanc.),Chongyi wild mandarin(C. reticulata‘Chongyi’),Poncirus trifoliata and Carrizo citrange(C. sisensis × P. trifoliata‘Carrizo’)were detached and dehydrated for 0,3,and 6 h. The results of relative water loss and electrolyte leakage indicated that the leaves of Sanhu red tangerine had the best water retention capacity and suffered the least cell membrane damage under dehydration. Stomatal density of the lower epidermis was counted via blotting,indicating that Sanhu red tangerine had the lowest stomatal density(325 · mm-2),significantly lower than the other three varieties(P < 0.05). Moreover,blotting using the dehydrated leaves showed that the stomatal aperture area of Sanhu red tangerine decreased more promptly in response to dehydration. In addition,leaf anatomical structure was compared via paraffin sectioning. The palisade parenchyma of Sanhu red tangerine was completely differentiated into two layers,but palisade parenchyma of the other three materials were relatively underdevelopped. The ratio of palisade parenchyma thickness and the sponge parenchyma thickness of Sanhu red tangerine was 0.56,which was significantly higher than that of the other three materials. Finally,principal component analysis indicated that the capacity of the four citrus germplasms tolerant to drought was: Sanhu red tangerine > P. trifoliata > Chongyi wild mandarin > Carrizo citrange. In conclusion,Sanhu red tangerine was the most drought-tolerant one among the four tested varieties,which could be used for drought-tolerant citrus breeding in the future.

    A Novel R2R3-MYB Transcription Factor Gene AaMYB6 Involved in Anthocyanin Biosynthesis in Anthurium andraeanum
    LI Chonghui, YANG Guangsui, ZHANG Zhiqun, YIN Junmei
    Acta Horticulturae Sinica    2021, 48 (10): 1859-1872.   DOI: 10.16420/j.issn.0513-353x.2021-0476
    Abstract366)   HTML21)    PDF (3457KB)(418)      

    A new R2R3-MYB gene AaMYB6 with GenBank accession number MZ171064 was isolated from the spadix of Anthurium andraeanum‘Pink Champion’based on the information from previous transcriptome data for identification of transcription factor genes associated with anthocyanin biosynthesis. The function of AaMYB6 was analyzed through the assays such as amino acid sequence alignment,phylogenetic tree analysis,subcellular localization,overexpression in tobacco,qRT-PCR,yeast two-hybrid assay(Y2H),and bimolecular fluorescence complementation(BiFC). The results suggested that AaMYB6 showed homology with previously identified AaMYB1 from anthurium and belong to C1 subgroup R2R3-MYBs,represented by Zea may C1,that regulate anthocyanin biosynthesis in monocots. AaMYB6 was proved to be nucleus-localized protein. Overexpression of AaMYB6 in tobacco markedly activated the expression of the enzyme genes NtF3′H,NtDFR,NtANS,NtUFGT,specifically involved in anthocyanin biosynthesis in filaments and promoted the accumulation of anthocyanin pigments. AaMYB6 was mainly expressed in the spadix of‘Rapido’. And the expression of AaMYB6 was closely linked to anthocyanin accumulation in the spadix of various cultivars. The interaction between AaMYB6 and the AabHLH1 protein,which was identified previously to regulate the biosynthesis of anthocyanin and proanthocyanidin in anthurium,was confirmed by Y2H and BiFC assays. The results indicated that AaMYB6 play a role in the regulation of anthocyanin biosynthesis in anthurium.