Research Papers

• Ethylene is Involved in the Regulation of Stomatal Movement by ALA-ABA/dark in Apple Leaves
• HU Shu，AN Yuyan，and WANG Liangju*
• Acta Horticulturae Sinica. 2020, 47(3): 409-420. DOI:10.16420/j.issn.0513-353x.2019-0370
• Abstract ( 475 ) HTML ( 675 ) PDF (1554KB) ( 675 ) 　　　
• In order to investigate the possible regulatory roles of the gaseous hormone ethylene in the inhibitory effect of ALA on ABA- or dark-induced stomatal closure，the stomatal aperture，ethylene production，H2O2 and flavonol levels in guard cells and gene expressions in the abaxial epidermis of detached apple（Malus × domestica Borkh.‘Fuji’）leaves were studied using pharmacology，gas chromatography，laser confocal scanning microscope，optical microscope and qRT-PCR techniques. The results showed that the ALA treatment promoted ethylene release，while both aminoethoxyvinylglycine （AVG），an ethylene biosynthetic inhibitor，and 1-methylcyclopropene（1-MCP），an ethylene receptor inhibitor，repressed the inhibitory effect of ALA on ABA or dark-induced stomatal closure. Exogenous ALA up-regulated expression of the genes related to ethylene biosynthesis and its signal transduction. AVG weakened the inhibition of ALA on ABA- and dark-induced H2O2 accumulation，as well as ALA-induced flavonol accumulation in guard cells. It can be concluded that ALA up-regulates gene expressions to induce ethylene biosynthesis and signal transduction，which positively regulate the flavonol accumulation to reduce the H2O2 content and promote the stomatal opening，benefiting CO2 entrance during photosynthesis.
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• Effect of Different Planting Densities on Growth，Distribution of Light in the Canopy and Yield of‘Fuji’Apple Trees on Dwarfing Interstocks
• LI Minji，ZHANG Qiang，LI Xingliang，ZHOU Beibei，GAO Muwang，YANG Yuzhang，ZHOU Jia，ZHANG Junke，and WEI Qinping*
• Acta Horticulturae Sinica. 2020, 47(3): 421-431. DOI:10.16420/j.issn.0513-353x.2019-0448
• Abstract ( 349 ) HTML ( 582 ) PDF (2361KB) ( 582 ) 　　　
• The‘Fuji’apple with SH6 dwarf interstock planted in spring 2011 was used to investigate the effect of 7 different tree planting densities（1 m × 3 m，1.5 m × 3 m，2 m × 3 m，0.75 m × 4 m，1 m × 4 m，1.25 m × 4 m and 1.5 m × 4 m）on growth，distribution of light in the canopy，yield and quality in Beijing from 2012 to 2018. By the 7th year of planting，the total number of branches in 1 m × 3 m and 0.75 m × 4 m planting densities exceeded 1.4 million · hm-2，and by the 8th year of planting，the total number of branches in each planting density exceeded 1.4 million · hm-2. In the first four years，with the growth of age，the proportion of long branch was decreased，the increasing proportion of short branches of all planting densities was increased. From the fifth year，the number and proportion of branches of different lengths began to be stable. According to the branch composition of trees with stable yield for 3 years，the proportion of short branches with 4 m row spacing was significantly higher than that with 3 m row spacing，while the proportion of long branches was slightly lower. Under different planting densities，there were great differences in the distribution of canopy light. The average relative light intensity of canopy was 1.5 m × 4 m（63.87%），1.25 m × 4 m（61.44%），2 m × 3 m（61.27%），1 m × 4 m（59.19%），0.75 m × 4 m（55.79%），1.5 m × 3 m（53.67%）and 1 m × 3 m（49.37%）from high to low. Under the same plant number，the proportion of low light efficiency（relative light intensity less than 40%）in 4 m row spacing treatment was significantly less than that in 3 m row spacing treatment. Compared with the cumulative yield in the previous five years，row spacing of 4 m was significantly better than row spacing of 3 m，and the cumulative fruit yield was the highest under three planting densities of 0.75 m × 4 m，1 m × 4 m and 1.25 m × 4 m. According to the results of three years’ stable yield，the order of big fruit rate（the proportion of fruit weight > 200 g to total yield）from high to low was 1.25 m × 4 m > 1.5 m × 4 m > 1 m × 4 m > 2 m × 3 m > 0.75 m × 4 m > 1.5 m × 3 m > 1 m × 3 m，and the big fruit rate of 4 m row spacing was obviously higher than that of 3 m row spacing. Comparing the fruit quality of different planting densities，there were no significant differences in soluble solids content，solid-acid ratio，fruit shape index and fruit firmness among different planting densities. We recommend using row spacing of 4 m and plant spacing of 1–1.25 m in production.
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• Interacting Protein Screening and Analysis of CsAP2-09 — A Citrus Bacterial Canker Related Transcription Factor
• QI Jingjing*，DOU Wanfu*，ZHANG Qingwen，HU Anhua，CHEN Shanchun，LEI Tiangang，PENG Aihong，XU Lanzhen，YAO Lixiao，HE Yongrui**，and LI Qiang**
• Acta Horticulturae Sinica. 2020, 47(3): 432-444. DOI:10.16420/j.issn.0513-353x.2019-403
• Abstract ( 406 ) HTML ( 611 ) PDF (2095KB) ( 611 ) 　　　
• CsAP2-09 is a positive transcription factor involved in the citrus bacterial canker resistance. In this study，the GST pull-down and LC–MS/MS strategies were used for the screening and network analysis of the interacting proteins of CsAP2-09. Firstly，the fusion proteins GST-CsAP2-09 were expressed and purified for the next GST pull-down. Then GST-CsAP2-09 was fixed on the GST-beads and incubated with total proteins extracted from CsAP2-09 over-expression plant. The interacting proteins of CsAP2-09 were detected by LC–MS/MS. From the annotation，GO and KEGG，17 interacting proteins were obtained，5 of which were reported to be involved in bacterial resistance，e.g. Cs3g27280（CAT）-a catalase.The interacting network was constructed，among which 14 of 17 interacting proteins were involved. Sixteen proteins were positively regulated by CsAP2-09 in the transgenic plant while 1 protein was negatively regulated.
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• Cloning and Expression Analysis of Alcohol Dehydrogenase Gene CsADH1Responding to Huanglongbing Infection in Citrus
• XIE Zhu，ZHAO Ke，ZHENG Lin，LONG Junhong，DU Meixia，HE Yongrui，CHEN Shanchun*，and ZOU Xiuping*
• Acta Horticulturae Sinica. 2020, 47(3): 445-454. DOI:10.16420/j.issn.0513-353x.2019-0773
• Abstract ( 414 ) HTML ( 688 ) PDF (1484KB) ( 688 ) 　　　
• Huanglongbing（HLB）often causes the loss and abnormal distribution of zinc（Zn）element in citrus plant. Zn，which is required for activity of alcohol dehydrogenases（ADH），plays important roles in regulation of ADH responding to biotic- and abiotic-stress. Our proteome sequencing showed that a citrus alcohol dehydrogenase 1（CsADH1）had significantly different expression in HLB-affected citrus compared with healthy control. Here，the 1 143 bp-long CDS sequence of CsADH1，which encodes a protein of 380 amino acid residues，was cloned from‘Wanjincheng’orange（Citrus sinensis Osbeck）. Informatic analysis showed that CsADH1 had the GroES and ADH_zinc_N functional domains. Sequence alignment showed that CsADH1 shared high amino acid identities with alcohol dehydrogenase（ADH）members from Arabidopsis，castor and lotus. Subcellular localization analysis showed that CsADH1 protein located in the cytoplasm of onion epidermic cells. Real-time quantitative analysis revealed that CsADH1 had up-regulated expression in root and midrib of‘Wanjincheng’orange after HLB pathogen infection and the expression level in root was 10 times higher than that in midrib. CsADH1 expression was also upregulated by Zn ion，salicylic acid（SA），auxin（IAA）and abscisic acid（ABA）induction and its expression levels in roots were obviously higher than that in leaves. The results suggested that CsADH1 play a more important role in the responses of citrus roots to HLB infection compared with midrib.
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• Embryonary Sac Regenerated Plants Were Obtained in Cucumber via in Vitro Unpollinated Ovary Culture
• ZHOU Xia1，ZHANG Lu1，ZHOU Junguo2，DENG Ying3，WANG Yi1，LOU Qunfeng1，and CHEN Jinfeng1,*
• Acta Horticulturae Sinica. 2020, 47(3): 455-466. DOI:10.16420/j.issn.0513-353x.2019-0393
• Abstract ( 392 ) HTML ( 801 ) PDF (3870KB) ( 801 ) 　　　
• Seven kinds of F1 generation cucumber unpollinated ovary were used as test materials for regenerated plant cultivation. Paraffin sections of ovary were observed，and hormone content of ovary slices at different culture stages were measured to explore the formation process and related physiological changes of embryonary sac regenerated plants. The results showed that the regenerated plants were obtained from unpollinated ovary culture of cucumbers with three donor materials under MS + 0.06mg · L-1 TDZ medium，which were identified as haploid，double haploid and autotetraploid respectively by flow cytometry，chromosome count and SSR. A large number of embryonary like structures were produced in ovary under MS + 0.04 mg · L-1 TDZ + 1.0 mg · L-1 6-BA + 0.1 mg · L-1 NAA + 12 mg · L-1 AgNO3medium，but no regenerated plants were obtained after differentiation culture. The embryonary sac underMS and MS + 0.06 mg · L-1 TDZ medium was observed to develop on the 5th and 17th day by paraffin sections. Hormone determination suggested that the content of GA and IAA are on the decline to the lowest at the 8th day and increased subsequently. The GA content in the ovary slices at 17 d was higher than that in the culture for 2 d，but the variation of IAA content is slight.
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• Growth and Development of Hypsizygus marmoreus and Response Expression of Light Receptor White Collar Genes Under Different Light Quality Irradiation
• SONG Hanbing1,2，LI Yong1,2，HUANG Jiahua1,2，DUAN Jingyi1,2，ZHANG Qisi1,2，XIE Baogui2，and
• Acta Horticulturae Sinica. 2020, 47(3): 467-476. DOI:10.16420/j.issn.0513-353x.2019-0510
• Abstract ( 343 ) HTML ( 513 ) PDF (2479KB) ( 513 ) 　　　
• It this study，the lights with five different waves were used to illuminate the mycelia，primordia and fruiting body of Hypsizygus marmoreus，respectively and the growth rate of the hypha，the number of the primordia，the stipe length and diameter，the pileus diameter as well as the yield of the fruiting body of H. marmoreus were detected. The results showed that hypha of H. marmoreus grew faster under the darkness condition or the red light，and the slowest under the red-green-blue composite light. The number of primordia of H. marmoreus was the most under the blue light，while the least under the red light. For the fruiting body of H. marmoreus，the length and diameter of the stipe were the largest under the darkness condition，while the smallest under the green light. The diameter of the pileus was larger under the blue light or the red-green-blue composite light. Under the same cultivation time，the yield of H. marmoreus was the highest under the darkness or the blue light condition，while the lowest under the green light. Further，the differential expression of two photoreceptors WC1 and WC2 under the above different light conditions was also detected by qPCR. In the stipe，the WC1 gene exhibited the highest expression under the darkness condition，while the WC2 gene exhibited the highest under the blue light. In the pileus， both WC1 and WC2 showed the highest expression level under the blue light.
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• Effects of Cell Sap pH on the Flower Color Formation in Primula vulgaris
• ZHAI Yuhui，Lü Jiaqi，LI Xiang，LUO Xiaoning，LI Long，and SHI Qianqian*
• Acta Horticulturae Sinica. 2020, 47(3): 477-491. DOI:10.16420/j.issn.0513-353x.2019-0228
• Abstract ( 292 ) HTML ( 525 ) PDF (2964KB) ( 525 ) 　　　
• To study the mechanism of cell sap pH on flower color formation in Primula vulgaris，petals of pink，red，white，yellow and blue were used as materials. The flower color indices were measured using CIE L*a*b* system，and the cell sap pH values in different colored petals were measured by planar pH meter. Furthermore，the composition and content of anthocyanin，flavonoids and carotenoid were assessed qualitatively and quantitatively by UPLC. And then，the color change and absorbance change of cell sap in different external buffer solutions were observed using UV spectrophotometer. The results showed that cell sap pH value was the lowest in red（5.07），followed by pink，white and yellow，and the highest in blue petal（6.33）. The anthocyanidins were accumulated abundantly in pink，red and blue petals while the contents of flavonoids were the highest in white and yellow petals. Meanwhile，the cell sap pH values showed significantly positive correlations with the content of delphinidin-3-glucoside，hirsutin， petunidin-7- methoxy-3，5-diglucoside，malvidin-3-glucoside and hirsutin-4’-malonate，which all were specific in blue petals. Moreover，there was a bathochromic shift in the visible light region of the maximum absorption peak of pink，red and blue cultivars’ petal pigment extracting solution，and the color of pigment extracting solution of pink，red and blue petals was fading gradually with the increasing of buffer solution pH，and then turned into yellow. In addition，based on the results from expression profiles， the correlation between cell sap pH and gene expression，and the bioinformatics analysis，the relative expression of PvPH4 in blue petals was significantly higher than those in the other four colored petals. Furthermore，the relative expression of PvPH4 showed significantly positive correlation with cell sap pH. The conserved domain of PvPH4 was caca2，which belonged to ChaA superfamily. And the tertiary structure modeling of the protein showed that the similarity to the vacuolar calcium ion transporter was 39%. Thus，PvPH4 may play a role on flower color by encoding vacuolar calcium ion transporter to influence the petal cell sap pH.
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• Studies on Floral Syndrome and Breeding System of Primulina hunanensis
• LI Shuaijie and CAI Xiuzhen*
• Acta Horticulturae Sinica. 2020, 47(3): 492-502. DOI:10.16420/j.issn.0513-353x.2019-0651
• Abstract ( 238 ) HTML ( 459 ) PDF (8937KB) ( 459 ) 　　　
• For rational development and utilization of the wild germplasm resources of Primulina hunanensis，the role of the floral syndrome and breeding system on its sexual reproduction process was evaluated. The flowering phenology，floral features，and flower-visiting insects of P. hunanensis were recorded by field observation. We analyzed pollen viability and stigma receptivity，pollen/ovule ratio，and hybridization index，combined with artificial pollination experiment to test its breeding system. The result showed：(1) P. hunanensis flowered from May to July，with a flowering period of about 40 d and a single flowering cycle of 3–8 d. When the flowers were just open，the pollen was the most energetic（> 90%）in the flowering period，and the stigma was inactive，indicated that pistil and stamens of P. hunanensismatured at different times. After flowering，the growth of the stamens of P. hunanensis almost stopped，but its pistil continued to elongate，indicating that the pistils and stamens had different spatial positions. (2) The ratio of pollen and ovule was 518.36. The hybridization index was 5，indicating the breeding system of P. hunanensis was outcrossing，partial self-compatibility and demanded pollinators. The seed setting rate of P. hunanensis was not 0，and there was no apomixis in the bagged and emasculation experiment. (3) Many kinds of flower-visiting insects were surveyed in the P. hunanensis population. During the flowering period，Bombus sp. was the most effective pollinator which was adapted to its floral syndrome. (4) Under field condition，the fruit setting rate of P. hunanensis was higher. Asexual reproduction occurred in the population of P. hunanensis，maintaining the population as a reproductive compensation mechanism.
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• Karyotype Analysis of Rosa praelucens and Its Closely Related Congeneric Species Based on FISH
• FANG Qiao1,2，TIAN Min1，ZHANG Ting1，WANG Qigang1，YAN Huijun1，QIU Xianqin1，ZHOU Ningning1，ZHANG Hao1，JIAN Hongying1,*，and TANG Kaixue1,*
• Acta Horticulturae Sinica. 2020, 47(3): 503-516. DOI:10.16420/j.issn.0513-353x.2019-0349
• Abstract ( 300 ) HTML ( 512 ) PDF (3441KB) ( 512 ) 　　　
• In order to identify the possible original ancestors of the allodecaploid Rosa praelucens Byhouwer，the cytological Fluorescence in situ Hybridization（FISH）with 45S rDNA and 5S rDNA as probes was used to study the karyotypes of R. praelucens and 20 other closely related and sympatrically distributed congeneric species. The results were as follows：(1) Among the studied 21 rose species，only the karyotype of R. praelucens was 2B，and that of the other 20 species all belonged to 2A. (2) The number of 45S rDNA hybridization sites in 20 rose species was identical to their ploidy number in interphase cells， except for that of the diploid R. banksiopsis，which had three 45S rDNA hybridization sites. The number of 45S rDNA sites equaled to its ploidy number in metaphase cells. Some 45S rDNA loci in 14 species， namely，R. graciliflora，R. omeiensis var. omeiensis，R. sericea，R. mairei，R. sertata，R. davidii，R. banksiopsis，R. persetosa，R. macrophylla，R. acicularis，R. moyesii，R. odorata var. pseudoindica， R. roxburghii and R. praelucens were fragile sites. (3) The number and location of 5S rDNA loci were uncertain. Diploid R. willmottiae var. glandulifera，R. odorata var. pseudoindica，R. helenae，R. brunonii and R. soulieana var. soulieana all had four 5S rDNA hybridization sites in both interphase and metaphase cells. In addition，there were four 5S rDNA hybridization sites in the interphase of diploids R. davidii and R. banksiopsis，but only two 5S rDNA hybridization sites could be observed in metaphase. The number of 5S rDNA hybridization loci of other 14 species in both interphase and metaphase were identical to their ploidy. These results indicated that FISH with 45S rDNA and 5S rDNA as probes could identify some of the chromosomes more accurately and thus could improve the results of karyological study of genus Rosa. Based on the mapping of rDNA in the chromosomes of R. praelucens and its 20 relative species，it could be postulated that R. graciliflora，R. moyesii and R. murielae were the possible original ancestors of R. praelucens.
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• Genome-wide Identification and Expression Analyses of PAL Genes Under Biotic and Abiotic Stress in Camellia sinensis
• XIONG Fei1,2，LU Qinhua1，FANG Wanping2，YANG Yajun1，WANG Xinchao1，ZHU Xujun2,*，and WANG Yuchun1,*
• Acta Horticulturae Sinica. 2020, 47(3): 517-528. DOI:10.16420/j.issn.0513-353x.2019-0376
• Abstract ( 455 ) HTML ( 748 ) PDF (1763KB) ( 748 ) 　　　
• Phenylalanine ammonia-lyase（PAL）plays important roles in plant stress resistance. Based on bioinformatics analyses，five and six PAL genes were identified from the genomes of Camellia sinensis var. assamica‘Yunkang 10’and Camellia sinensis var. sinensis‘Longjing 43’respectively. Homology analysis showed that the CsPAL proteins had low homology to the proteins of Arabidopsis thaliana and Populus trichocarpa，and showed different evolutionary relationship between‘Longjing 43’and‘Yunkang 10’. Transcriptome data further showed that CsPAL genes could be significantly induced under salt stress and methyl jasmonate treatment，while not for cold and drought stresses. Tissue-specific expression of PAL genes showed relatively low transcript abundance in the old leaves of tea plant，but high in young tissues and roots，and particularly the expression of CsPALa，CsPALc，CsPALe were the highest in flowers. Furthermore, qRT-PCR detection showed that the expression of six CsPAL genes were significantly up-regulated after inoculation at 24 h with Colletotrichum camelliae，Pseudopestalotiopsis camelliaesinensis and Ectropis oblique in‘Longjing 43’and new line‘2807’. The above results indicate that the PAL genes of tea plant play important roles in dealing with different stresses.
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Research Notes

• Effects of Low Potassium Stress on Photosynthetic Fluorescence Characteristics and 13C Absorption and Distribution of M9T337 Seedlings
• XU Xinxiang，HOU Xin，WANG Fen，JIA Zhihang，GE Shunfeng*，and JIANG Yuanmao*
• Acta Horticulturae Sinica. 2020, 47(3): 529-540. DOI:10.16420/j.issn.0513-353x.2019-0484
• Abstract ( 453 ) HTML ( 589 ) PDF (851KB) ( 589 ) 　　　
• Hydroponic culture method was used with M9T337 dwarf rootstock seedlings as tested materials，the chlorophyll fluorescence analysis and track technology of 13C were used to study the effect of different potassium supply levels（0.02，0.5，2，6 mmol · L-1）on photosyntheticphysiological characteristics，chlorophyll fluorescence characteristics and 13C photosynthate accumulation of seedlings. The results showed that compared with 6 mmol · L-1 K+treatment，the biomass of all organs，net photosynthetic rate（Pn）and stomatal conductance（Gs）of M9T337 seedlings significantly decreased under low potassium stress while the intercellular CO2 concentration（Ci）first decreased and then increased. The coefficient of photochemical quenching（qP），PSⅡactual photochemical efficiency（ΦPSⅡ），PSⅡelectron transport rate（ETR）and PSII maximum photochemical efficiency（Fv/Fm）in leaves of M9T337 seedlings dropped significantly under low potassium stress，based fluorescence（F0）and the coefficient of photochemical quenching（NPQ）significantly increased，and the greater the degree of stress，the greater the change in chlorophyll fluorescence parameters. With the prolongation of treatment time，the activities of RuBP carboxylase（Rubisco）and carbon metabolic enzyme decreased gradually under low potassium stress，and reached the lowest level after 35 days. The results of 13C tracer test showed that low potassium stress significantly affected the accumulation and distribution of carbon assimilates. Six hours after 13C labeling，the accumulations of 13C in roots of seedlings under 0.02，0.5 and 2 mmol · L-1 K+ treatment were 15.59%，26.62%，59.72% of that under 6 mmol · L-1 K+treatment，respectively. After 72 h，the 13C distribution rates of seedling leaves under 0.02，0.5 and 2 mmol · L-1 K+ treatment were as high as 70.44%，67.61%，66.02%，respectively，14.00%，9.44%，6.87% higher than 6 mmol · L-1 K+ treatment；while the 13C distribution rates of 0.02，0.5 and 2 mmol · L-1 K+ treated seedling roots were 10.54%，11.84%，13.34%，respectively，which were 61.87%，69.50%，78.31% of 6 mmol · L-1 K+ treatment. The result showed that low potassium stress can reduce stomatal conductance of leaves，destroy PSⅡreaction center，reduce the supply of reducing power and carbon assimilation ability in photoreaction stage，thus inhibiting photosynthesis and carbon transport to roots of seedlings，and the degree of inhibition is significantly related to potassium stress time and degree.
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• Effect of Bi-axis Bibaum Tree Shape on Growth and Bearing of Young Apple Tree on Dwarf Rootstock
• MA Xiaolong1，MA Doudou1，SHI Jidong3，HAN Mingyu1，YANG Weiwei2,*，and ZHANG Dong1,*
• Acta Horticulturae Sinica. 2020, 47(3): 541-550. DOI:10.16420/j.issn.0513-353x.2019-0193
• Abstract ( 663 ) HTML ( 445 ) PDF (768KB) ( 445 ) 　　　
• In this study，‘Fujiko’（a long shoot-type Fuji series cultivar）young apple trees on M9-T337 dwarf rootstocks were selected as the test material，growth，shoot constitution proportion， flowering ratio，fruit quality and yield were investigated between Bibaum?（1.2 m × 3.5 m）and tall spindle （1.0 m × 3.5 m）tree shapes，in order to explore the performance on tree growth and bearing of Fuji apple with bi-axis Bibaum tree shape in Chinese Weibei Loess Plateau. The results showed that plant height，trunk diameter and east-west crown diameter（between rows）of Bibaum tree in 2016 were significantly smaller than tall spindle，and the rootstock diameter was greater than tall spindle tree. Number of shoots per plant and per hectare were higher in tall spindle trees in 2016，while no significant difference was observed in 2017. The increase rates of height，trunk diameter，rootstock diameter and shoot number per hectare were higher in Bibaum trees from 2016 to 2017. Moreover，proportions of medium shoots（5–15 cm）and bourse long shoots in 2016 were higher in Bibaum trees，while it was lower for the proportion of vegetative long shoots（> 30 cm）in Bibaum in 2017. Simultaneously，the flowering ratio of Bibaum trees was significantly higher in 2018. No significant difference was observed in fruit quality and yield per hectare between two tree shapes，nevertheless the fruit number，yield per tree in 2017，and the increase of yield for Bibaum from 2016 to 2017 were higher than that of tall spindle trees. In conclusion，Fuji series apple trees on dwarf rootstocks with Bibaum tree shape can significantly reduce tree height，meanwhile Bibaum showed flatter tree shape，rapid tree growth，increase in number of shoots，easier to produce flowers，less proportion of vegetative long shoots，and higher potential in increasing yield.
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• Enhanced Dehydration Tolerance in Lemon by Overexpression of CrNCED1（9-cis-epoxycarotenoid dioxygenase gene）from Citrus reshni
• DAI Wenshan1,2，WANG Min1,2，and LIU Jihong1,*
• Acta Horticulturae Sinica. 2020, 47(3): 551-561. DOI:10.16420/j.issn.0513-353x.2019-0375
• Abstract ( 391 ) HTML ( 517 ) PDF (1983KB) ( 517 ) 　　　
• To explore the function of CrNCED1，a key enzyme gene during abscisic acid biosynthesis in Cleopatra Mandarin（Citrus reshni），the expression characteristics of CrNCED1 was analyzed. Transgenic plants were obtained by overexpression of CrNCED1 in lemon for assaying dehydration resistance. The results showed that CrNCED1 showed the highest expression levels in leaves of Citrus reshni. Transcript levels of CrNCED1 were induced by dehydration，low temperature and ABA，but not by salt stress，among which ABA treatment strongly induced the expression of CrNCED1. The ABA content of transgenic lemon plants overexpressing CrNCED1 was remarkably higher than that of wild type. Upon exposure to dehydration treatment，the transgenic lines displayed less severe leaf wilting degree，concurrent with noticeably lower relative water loss，MDA and reactive oxygen species contents，and substantially smaller stomatal aperture in comparison with the wild type，indicating that overexpression of CrNCED1 conferred enhanced dehydration resistance in transgenic lemon plants.
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• Germplasm Innovation of Pest-resistant Asparagus Bean by Interspecific Crosses
• SHAO Jingjie，PAN Lei，WAN Heping，GUO Rui，CHEN Gao，XIE Qian，REN Sanguo，LU Shuang，YAN Mu，and CHEN Chanyou*
• Acta Horticulturae Sinica. 2020, 47(3): 562-570. DOI:10.16420/j.issn.0513-353x.2019-0411
• Abstract ( 327 ) HTML ( 427 ) PDF (1164KB) ( 427 ) 　　　
• The interspecific crosses of asparagus bean（Vigna unguiculata L. ssp. sesquipedalis）and its related species of rice bean[V. umbellata（Thunb.）Ohwi & Ohashi]were carried out. The pest-resistance level and pod traits of the parents and their 7th generations were identified and evaluated. The results showed that the pest-resistance levels of rice bean varieties were generally higher than that of asparagus bean varieties in the field. Meanwhile，41 individual plants showing resistance to pest were selected from 363 lines containing all kinds of segregation in F6 generation of interspecific crosses between asparagus bean and rice bean. They constituted F7 generation. The field experiment results revealed that the pest-resistance levels of F7 offspring were separated significantly and seven recombinant lines with high resistance（HR）level were re-selected. Finally，according to the characteristics of pod-related traits such as pod length and grain density，two within the seven lines with HR level to Prodenia litura Fabricius and Spodoptera exigua Hübner at vegetative growth stage，and similar pod traits to asparagus bean were selected. Therefore，the germplasm innovation of asparagus bean pest-resistance was realized.
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• Identification of Quantitative Trait Loci Controlling Tomato Fruit Weight by QTL-seq
• WEI Kai1，LIU Xiaoyan1,2，CAO Xue1，LIU Xiaolin1，WANG Xiaotian1，YANG Mengxia1，WANG Jing1，WANG Xiaoxuan1，GUO Yanmei1，DU Yongchen1，LI Junming1，LIU Lei1，SHU Jinshuai1，QIN Yong2，and HUANG Zejun1,*
• Acta Horticulturae Sinica. 2020, 47(3): 571-580. DOI:10.16420/j.issn.0513-353x.2018-1058
• Abstract ( 398 ) HTML ( 604 ) PDF (1291KB) ( 604 ) 　　　
• The fruit weight of F1 generation derived from the cross between cherry tomato‘VFNT Cherry’（syn. LA1221）and processed tomato‘Heinz1706’was over parents，showing obvious heterosis. In order to analyze the genetic basis of this phenomenon，using F2 population obtained from the above F1generation self-crossing，the QTL mapping of tomato fruit weight was carried out by QTL-seq and single marker analysis. A total of ten fruit weight QTLs were identified，and eight of which were dominant. Among the eight dominant QTLs，five QTLs were incomplete dominant[QTL for Fruit Weight 2.1（qFW2.1），qFW5.2，qFW7.1，qFW8.1，qFW9.1]，and three QTLs were over-dominant[qFW1.1，qFW5.1，qFW6.1]. Moreover，the big fruit alleles of qFW2.1，qFW5.1，qFW7.1，qFW8.1，and qFW9.1 were from‘Heinz1706’，and the big fruit alleles of qFW1.1，qFW5.2，qFW6.1 were from‘VFNT Cherry’. Therefore，the heterosis of tomato fruit weight in the above F1 generation may be due to its aggregation of dominant large fruit alleles from both parents. Among the eight dominant QTLs，qFW9.1 had the highest contribution rate of phenotypic variation，reaching 12.19%. The qFW9.1 locus was further validated and narrowed to a 4.5 megabase pair by recombinant progeny testing
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• Molecular Cloning and Expression Characterization of Cyclophilin Gene（DoCyP）in Dendrobium officinale
• FU Yajuan1,2，CHEN Xiating1，QIAO Jie1,2，WANG Jing1,2，LI Wenjing1，and HOU Xiaoqiang1,2,*
• Acta Horticulturae Sinica. 2020, 47(3): 581-589. DOI:10.16420/j.issn.0513-353x.2019-0357
• Abstract ( 302 ) HTML ( 517 ) PDF (1229KB) ( 517 ) 　　　
• The cyclophilin gene（DoCyP）in Dendrobium officinale was cloned by RT-PCR. The full-length of DoCyP was 522 bp，encoding 173 amino acids. Bioinformatics predicted that DoCyP is a stable hydrophilic protein with a relative molecular mass of 18.25 kD，containing a peptide-prolyl cis-transisomerase domain. The theoretical isoelectric point of DoCyP is 8.72，and no transmembrane domain. SOPMA predicted that the secondary structure of DoCyP primarily consists of random coils and extended chains. The phylogenetic tree indicated that DoCyP of D. officinale has a relatively close genetic relationship with Apostasia shenzhenica CyP. qRT-PCR results revealed that DoCyP was constitutively expressed in different tissues of D. officinale. The relative expression of DoCyP was higher in roots，compared to leaves and stems. Under low-temperature（4 ℃）stress，the expression of DoCyP in different D. officinale tissues showed different trends. Compared with normal expression level，DoCyP expression after treatment with 4 ℃ for 12 h was up-regulated in roots，while down-regulated in stems and leaves，suggesting that DoCyP may take part in response to low temperature stress in D. officinale.
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• Cloning and Expression Analysis of EuCML5 Gene in Eucommia ulmoides
• LIU Wei1,3,*，TENG Teng2,3,*，ZHAO Yichen2,3,**，and ZHAO Degang3,4
• Acta Horticulturae Sinica. 2020, 47(3): 590-600. DOI:10.16420/j.issn.0513-353x.2019-0432
• Abstract ( 256 ) HTML ( 448 ) PDF (1489KB) ( 448 ) 　　　
• Based on the Eucommia ulmoides genome database，the Calmodulin-like（CML）gene EuCML5 was cloned. The open reading frame of EuCML5 was 282 bp in length，encoding a total of 93 amino acids. It contained no transmembrane structure and signal peptide，belonging to intracellular protein. The amino acid sequence contained the EF-Hand motif，close to calmodulin-like protein of some woody plants in evolutionary relationship. Quantitative real-time PCR analysis revealed that the expression of EuCML5 was higher in Eucommia ulmoides roots and lower in stems and leaves. After treatment with drough（Mannitol），salt，methyl jasmonate and auxin，the expression of EuCML5 in Eucommia ulmoides was increased，indicating that EuCML5 can be induced by abiotic stress and phytohormone.In addition，calcium channel inhibitors LaCl3 and calmodulin antagonist TFP inhibited EuCML5expression.
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New Cultivars

• A New Walnut Cultivar‘Nonghe 1’
• DING Xinxin1，ZHANG Xiaojun1，ZHANG Qingyuan2，LI Qiuyu1，NIU Tiequan1，HAO Yanyan1，and LIU Qunlong1,*
• Acta Horticulturae Sinica. 2020, 47(3): 601-602. DOI:10.16420/j.issn.0513-353x.2018-0930
• Abstract ( 275 ) HTML ( 400 ) PDF (1423KB) ( 400 ) 　　　
• ‘Nonghe 1’is a new large fruit walnut cultivar selected from wild seedling resources in Shilou，Lüliang，Shanxi. The nut is long and oval in shape，its surface is smooth，the average nut weight is 18.31 g，the average kernel weight is 9.08 g，the average kernel rate is 49.75%. The suture is flat and tightly combined，each side of the middle suture has a deep hole. Shell thickness is 1.34 mm，dissepiment of nut shells is degradated or thin，so the whole kernel is easy to be taken out. The kernel is full，yellow-white，fragrant and sweet. The yield was 3 900 kg · hm-2. It has the characteristics of early fruit，high yield，strong growth potential，high resistance to cold，drought and infertility.
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• A New Cultivar of Actinidia arguta var. giraldii‘Qin Ziguang 1’
• ZHANG Ying，WU Yongpeng*，CHEN Chen，LI Bin，and MAO Zhuxin
• Acta Horticulturae Sinica. 2020, 47(3): 603-604. DOI:10.16420/j.issn.0513-353x.2018-0923
• Abstract ( 397 ) HTML ( 428 ) PDF (1011KB) ( 428 ) 　　　
• ‘Qin Ziguang 1’was a new octoploid cultivar that selected from the wild Actinidia arguta var. giraldii in Qinling Mountains. The fruit skin is purplish red and hairless. The fruit shape is long oval，and fruit weight is 5–8 g. It has red purple fruit flesh with high nutrition，including 6.04% total sugar content，1.39% total acid content，0.634 mg · g-1 vitamin C content，12.14% soluble solids content. The fruit has unique flavor with suitable sweetness and acidity. However，‘Qin Ziguang 1’has poor storage life and the fruit is easy to ripening after harvest. In Xi’an City，it blossoms in mid-May，matures in late September and leaves fall in mid-November. Cutting seedlings began to set fruit in 2–3 years，and the average yield was 7 500 kg · hm-2 at full fruit stage.
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• A New Suitable for Mechanized Harvesting and Heat-resistant Pak-choi Cultivar‘Xinxiaqing 6’
• LI Xiaofeng*，ZHU Hongfang*，ZHU Yuying**，HOU Ruixian，and ZHAI Wen
• Acta Horticulturae Sinica. 2020, 47(3): 605-606. DOI:10.16420/j.issn.0513-353x.2018-1021
• Abstract ( 549 ) HTML ( 411 ) PDF (1539KB) ( 411 ) 　　　
• ‘Xinxiaqing 6’pak-choi is a new suitable for mechanized harvesting and heat-resistant hybrid by crossing two self-incompatible line‘131-413’and‘134-412’with homozygous genotype and excellent traits. The plant is erect with compact plant type and vigorous growth，with glossy green outer leaves and wide-long green petiole. It showed long hypocotyls，heat resistance，high downy mildew disease resistance and high quality. It could be harvested at 15–25 days after seeding and its average yield could be up to 10 200 kg · hm-2 at 20 days after seeding. It is suitable for cultivation in Shanghai and the Yangtze River similar ecological conditions in spring，summer and autumn.
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• A New Winter Cabbage Hybrid‘Zhonggan 1305’
• ZHANG Yangyong，FANG Zhiyuan*，YANG Limei，LIU Yumei，ZHUANG Mu，Lü Honghao，LI Zhansheng，and WANG Yong
• Acta Horticulturae Sinica. 2020, 47(3): 607-608. DOI:10.16420/j.issn.0513-353x.2019-0875
• Abstract ( 500 ) HTML ( 440 ) PDF (1486KB) ( 440 ) 　　　
• ‘Zhonggan 1305’is a cabbage hybrid between cytoplasmic male sterile line CMS708-1-1 and self-incompatible inbred line 1186-1-2-3，special for over-wintering cultivation in the mid-lower reaches of Yangtze River. It takes about 160 days from transplant to harvest when planted in the open field of Yangtze River Basin as winter cabbage. The head is round in shape and green in color，with the weight of 1.2 kg. It is tolerant to the low temperature，head cracking，and premature bolting. It is resistant to Fusarium wilt. It is suitable for over-wintering cultivation in Hubei，Hunan，Zhejiang，Henan，Jiangsu，etc.
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• A New Curcuma Cultivar‘Hongyu’
• ZENG Feng1，TAN Guangwen1，LIU Xiaozhou1，WANG Yongqi1，ZHAO Yangyang1，LUO Shuai1，SUN Huaizhi3，and LIU Nian2,*
• Acta Horticulturae Sinica. 2020, 47(3): 609-610. DOI:10.16420/j.issn.0513-353x.2018-1002
• Abstract ( 598 ) HTML ( 438 ) PDF (2527KB) ( 438 ) 　　　
• Curcuma‘Hongyu’is a hybrid of C. attenuata Wall. ex Baker and C. petiolata Roxb.，with strong growth potential，high flowering rate，bright flower color，long flowering period and strong adaptability. It is suitable for planting in Guangzhou and surrounding areas.
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