Woody Ornamental Plants Research Articles

Transcriptomic analysis of flower color variation in the ornamental crabapple (Malus spp.) half-sib family through Illumina and PacBio Sequel sequencing

Ornamental crabapple is an important woody ornamental plant with flower colors ranging from white to pink to red, and the degree of redness is directly related to the anthocyanin content. To explore the molecular mechanism leading to the variation in flower color in ornamental crabapple, transcriptome sequencing using the Illumina and PacBio Sequel platforms revealed the difference in gene expression between the petals of plants with white and red flowers in the half-sib family. In total, the analysis identified 603 differentially expressed genes (DEGs), including 449 upregulated and 154 downregulated genes. GO and KEGG enrichment analyses of the DEGs showed that the oxidation-reduction process and catalytic activity were more active in red petals, and most of the DEGs were involved in secondary metabolite synthesis and plant hormone signaling. Among the 603 DEGs, 10 were enriched as structural genes. Transcription factors related to anthocyanin synthesis and five genes related to anthocyanin transport and degradation were highly expressed in red petals. In addition, this study found that five AUX gene signals were differentially expressed in the two petal types. The discovery of these DEGs indicates that plant endogenous hormones also exert a regulatory effect on flower color.

Genome-Wide Analysis of NAC Transcription Factors and Characterization of the Cold Stress Response in Sweet Osmanthus

Sweet osmanthus (Osmanthus fragrans) is an evergreen aromatic woody tree widely used in landscaping. However, O. fragrans is very sensitive to cold stress, which seriously limits its cultivation and application in regions of low temperature. The NAC transcription factor gene family which has been characterized in many plant species could participate in multiple processes and play critical roles in plant response to external stress. However, little is known about this family in O. fragrans, an important woody ornamental plant. Here, the structural characteristics, chromosomal location, evolutionary relationship, cold stress expression patterns, and subcellular localization analysis of NAC family genes in O. fragrans were analyzed on a genome-wide scale. A total of 119 O. fragrans NAC genes were identified, and gene structure analysis showed that most OfNACs contained two introns, suggesting that structural diversity of the O. fragrans NAC family is relatively low. The phylogeny evolutionary tree showed that the NACs of O. fragrans were classified into 13 branches. The transcriptome data suggested that each branch members had different expression patterns in various tissues and a number of OfNACs showed tissue-specific expression profiles. The quantitative real-time PCR and subcellular localization results indicated that expression patterns of most branch ‘5B’ members were significantly induced by cold stress and they were mainly located in the nucleus, especially OfNAC49 and 59, indicating that branch ‘5B’ members could have important roles in cold tolerance in O. fragrans. Remarkably, expression levels of many branch ‘5B’ genes were also significantly changed under waterlogging stress, suggesting that this branch might be widely involved in tolerance to various abiotic stresses. Our study should supply useful gene resources for the cold resistance breeding of O. fragrans.

Plant regeneration in Ixora chinensis from young leaves

Ixora chinensis Lam. is a widespread tropical woody ornamental plant for its abundant and bright flowers. In this study, we established a regeneration system of I. chinensis for the first time using young leaves as explants on the Murashige and Skoog (MS) medium supplemented with different Plant Growth Regulators (PGRs). The optimal conditions for shoot regeneration include 4.0 mg/L 6-Benzylaminopurine (6-BA), 1.0 mg/L Thidiazuron (TDZ) and 1.0 mg/L α-Naphthalene acetic acid (NAA) with a shoot regeneration rate of 23.7%. Subculture of shoots on MS medium fortified with 1.0 mg/L 6-BA and 0.5 mg/L NAA achieved a survival ratio of 80.8% and rooting ratio of 30.5%. This result will be helpful in gene biotechnology to develop more colorful or fragrant flowers of I. chinensis in the future. This study is the first report to establish a regeneration system for Ixora chinensis.

Identification of SNP markers linked to the weeping trait in Prunus mume

Prunus mume is a traditional ornamental tree with a graceful architecture that blossoms early in spring and presents beautiful flowers with a pleasant fragrance. Recently, the weeping trait has received increasing attention for its ornamental appeal and potential application to agriculture. In this study, we identified the SNPs tightly linked to the weeping trait using a linkage population based on specific-locus amplified fragment sequencing (SLAF-Seq). Six SLAF-derived SNP markers (Marker446598, Marker353041, Marker315769, Marker334902, Marker301243 and Marker311414) were validated as being tightly associated with the weeping phenotype using Sanger sequencing. The Sanger sequencing results of Marker353041 indicated that 100% of the weeping individuals and 73.3% of the upright individuals were homozygous (AA) and heterozygous (AT), respectively. Two genotypes were identified using Marker301243 with allele-specific polymerase chain reaction. All upright individuals were heterozygous (TA) and only 16.7% of the weeping individuals heterozygous (TA) in the F1 segregated population. Two marker combinations led to 89.13% predictability in the cultivars. The results suggest the application of this approach for marker-assisted breeding of P. mume and lay the foundation for the molecular breeding process of the weeping trait in woody ornamental plants.

Genome-wide identification, characterization and expression analysis of the HD-Zip gene family in the stem development of the woody plant Prunus mume.

The homeodomain-leucine zipper (HD-Zip) gene family, a group of plant-specific transcriptional factors (TFs), participates in regulating growth, development, and environmental responses. However, the characteristics and biological functions of HD-Zip genes in Prunus mume, which blooms in late winter or early spring, have not been reported. In this study, 32 HD-Zip genes, named PmHB1–PmHB32 based on their chromosomal positions, were identified in the genome of P. mume. These genes are distributed among seven chromosomes and are phylogenetically clustered into four major groups. Gene structure and motif composition were mostly conserved in each group. The Ka/Ks ratios showed that purifying selection has played a leading role in the long-term evolution of the genes, which maintained the function of this family. MicroRNA target site prediction indicated that the genes of the HD-Zip III subfamily may be regulated by miR165/166. Expression pattern analysis showed that the 32 genes were differentially expressed across five different tissues (leaf, flower bud, stem, fruit, and root) and at different stages of stem and leaf-bud development, suggesting that 10 of the genes may play important roles in stem development. Protein–protein interaction predictions showed that the subfamily III genes may regulate vascular development and shoot apical meristem (SAM) maintenance. Promoter analysis showed that the HD-Zip III genes might be involved in responses to light, hormones, and abiotic stressors and stem development. Taken together, our results provide an overview of the HD-Zip family in P. mume and lay the foundation for the molecular breeding of woody ornamental plants.

Genome-wide identification and classification of the Hsf and sHsp gene families in Prunus mume, and transcriptional analysis under heat stress.

The transcriptional activation of heat shock proteins (Hsps) by heat shock transcription factors (Hsfs) is presumed to have a pivotal role in plant heat stress (HS) response. Prunus mume is an ornamental woody plant with distinctive features, including rich varieties and colors. In this study, 18 Hsfs and 24 small Hsps (sHsps) were identified in P. mume. Their chromosomal locations, protein domains, conserved motifs, phylogenetic relationships, and exon–intron structures were analyzed and compared with Arabidopsis thaliana Hsfs or sHsps. A total of 18 PmHsf members were classified into three major classes, A, B, and C. A total of 24 PmsHsps were grouped into eight subfamilies (CI to CIII, P, endoplasmic reticulum, M, and CI- or P-related). Quantitative reverse transcription PCR analysis revealed that members of the A2, A7, and A9 groups became the prominent Hsfs after heat shock, suggesting their involvement in a key regulatory role of heat tolerance. Most of the PmsHsp genes were up-regulated upon exposure to HS. Overall, our data contribute to an improved understanding of the complexity of the P. mume Hsf and sHsp gene families, and provide a basis for directing future systematic studies investigating the roles of the Hsf and sHsp gene families.

Оптимизация парковых насаждений г. Ростова-на-Дону и Новочеркасска путем введения в озеленение видов рода ACER L.

Клены являются одними из лучших декоративных деревьев, использующихся в озеленении населенных пунктов в России и за рубежом. Актуальной задачей в засушливом регионе является биоэкологическое обоснование оптимизации биоразнообразия представителей рода Acer L. в озеленении общего пользования (парки, скверы, бульвары, уличные посадки) и уточнения рекомендаций производству по осуществлению озеленительных работ с участием видов рода Acer L. В статье представлен ассортимент древесных видов рода Acer L. рекомендованный для оптимизации озеленительных посадок г. РостовнаДону и Новочеркасск. Установлен рейтинг декоративных достоинств кленовых деревьев в сравнении с другими видами, используемыми в озеленении а также декоративная долговечность деревьев в городских условиях. Наивысшие баллы по декоративности у клена остролистного и явора (202 и 201 балл). Декоративная долговечность кленов составляет от 45 до 80 лет. Введение деревьев рода Acer L. в озеленение способствует обогащению ассортимента рекреационноозеленительных насаждений городской среды. Для объектов общего пользования Ростовской агломерации разработан ассортимент устойчивых декоративных древесных растений рода Acer L. для различных типов посадок. В уличных посадках рекомендуется высаживать: Acer platanoides L. A. platanoides Globosum, A. pseudoplatanus L., A. saccharinum L. В качестве солитеров использовать A. platanoides L. и его декоративные формы, A. platanoides Globosum, A. pseudoplatanus L., A. negundo L. (золотистая и пестролистная формы). Для живых изгородей A. ginnala L., A. tataricum L., A. campestre L. Опыты с использованием стимуляторов роста показали, что наилучшие показатели по изменению линейных размеров и накоплению фитомассы получены при использовании Крезацин 0,003 и САН 0,01. Наилучшего развития достигли Acer L. на удобренном фоне с использованием ппрепаратов САН 0,01, Гумат 0,02 и 0,03. Обоснованы вопросы комплексной оценки состояния древесных видов рода Acer L. и базовые агротехнические технологии выращивания посадочного материала для целей озеленения. Разработанные мероприятия по оптимизации видового состава озеленительных посадок способствуют улучшению декоративных функций парковых насаждений. Maples are one of the best ornamental trees used in landscaping settlements in Russia and abroad. An urgent task in the arid region is a bioecological rationale for optimizing the biodiversity of the Acer L. genus in public gardening (parks, squares, boulevards, street plantings) and clarifying the recommendations of production on the implementation of gardening works involving Acer L. The article presents an assortment of woody species of the genus Acer L. recommended for optimizing planting of trees in RostovonDon and Novocherkassk. The rating of the decorative qualities of maple trees has been established in comparison with other species used in gardening as well as decorative durability of trees in urban environments. The highest scores on decorativeness are among maple and sycamore maple (202 and 201 points). Decorative durability of maples ranges from 45 to 80 years. The introduction of trees of the genus Acer L. into landscaping contributes to the enrichment of the range of recreational and landscaping plantings of the urban environment. An assortment of resistant ornamental woody plants of the genus Acer L. has been developed for public facilities in Rostov city agglomeration for various types of planting. It is recommended to plant in street plantings: Acer platanoides L . A. platanoides Globosum, A. pseudoplatanus L., A. saccharinum L. As soliter use A. platanoides L. and its decorative forms, A. platanoides Globosum, A. pseudoplatanus L., A. negundo L. (golden and variegated forms). For hedges A. ginnala L., A. tataricum L., A. campestre L. Experiments with the use of growth stimulants showed that the best indicators of changes in linear dimensions and accumulation of phytomass were obtained using Krezacin 0.003 and SAN 0.01. Acer L. achieved the best development on a fertilized background using SAN preparations of 0.01, Humate 0.02 and 0.03. The issues of a comprehensive assessment of the status of tree species of the genus Acer L. and the basic agrotechnical technologies of growing planting material for gardening are substantiated. Developed measures to optimize the species composition of planting trees contribute to the improvement of the decorative functions of parkland.

Ornamental woody plants recommended for creating an all-season flower garden

Ornamental woody plants recommended for creating an all-season flower garden

Effect of Brassica crop-based biofumigation on soilborne disease suppression in woody ornamentals

Soilborne diseases are the most economically important problem for ornamental nursery producers in the southeastern United States. The use of cover crops selected based on their biofumigant activity to improve soilborne disease management in woody ornamental production was assessed. Replicated pot bioassays were established as greenhouse trials in sterilized clay loam soil which had pre-existing populations of Rhizoctonia solani or Phytophthora nicotianae. Selected Brassica crops were seeded directly into the soil and flowering cover crops were incorporated 15 cm deep into the same pots and covered with polyethylene for 2 or 4 weeks. Volatile compounds released during the biofumigation process were collected at different time intervals. Soil type and moisture affected ITC release. Hydrangea or viburnum rooted cuttings were grown in the biofumigated (2 or 4 weeks) and non-biofumigated control pots and root rot disease severity was evaluated at the end of each bioassay. Yellow mustard (Sinapis alba, ‘White gold’), turnip (Brassica rapa, ‘Purple top forage’), arugula (Eruca vesicaria ssp. sativa, ‘Astro’), Mighty mustard (B. juncea, ‘Pacific gold’), rape (B. napus, ‘Dwarf essex’), mustard green (B. carinata, ‘Amara’) and brown mustard (B. juncea, ‘Kodiak’) cover crops were effective in suppressing R. solani and P. nicotianae. Similar disease suppression was observed whether biofumigation was performed for 2 or 4 weeks. Phytotoxicity was not observed on viburnum and hydrangea woody ornamental plants after either the 2 or 4 weeks biofumigation period with any of the tested cover crops. Viburnum and hydrangea grown in mustard green-, arugula- and turnip-incorporated soil had significantly higher whole plant and root fresh weights compared with the inoculated, non-biofumigated control plants. Although mustard green and arugula are not used currently as commercial biofumigation cover crops, they also showed promise for controlling soilborne pathogens of woody ornamental plants under greenhouse conditions.

Effect of Organic Inputs and Solarization for the Suppression of Rhizoctonia solani in Woody Ornamental Plant Production.

Soilborne diseases are the most economically significant problem faced by Southern region nursery producers. The goal of this research was to improve Rhizoctonia root rot disease management through the use of soil solarization alone and in combination with biofumigant cover crops—arugula ‘Astro’ (Eruca vesicaria ssp. sativa), mustard green ‘Amara’ (Brassica carinata), and turnip ‘Purple top forage’ (B. rapa); good quality compost and mustard meal amendment. The experiments were established as on-farm trials in 2016 and 2017 with prevalent Rhizoctonia solani population in propagation beds. All three biofumigant cover crops, arugula ‘Astro’, mustard green ‘Amara’, and turnip ‘Purple top forage’ in combination with solarization were able to reduce the Rhizoctonia root rot in flowering cherry ‘Kwanzan’ plants in nursery propagation beds. Compost amendment increased the flowering cherry rooted cuttings growth (plant weight, root weight, and plant height) compared to other treatments. Soil solarization in combination with cover crops and organic inputs could be used as part of an integrated approach to manage Rhizoctonia root rot in nursery crop propagation beds.

Identification and comparative analysis of the CIPK gene family and characterization of the cold stress response in the woody plant Prunus mume.

Prunus mume is an important ornamental woody plant that grows in tropical and subtropical regions. Freezing stress can adversely impact plant productivity and limit the expansion of geographical locations. Understanding cold-responsive genes could potentially bring about the development of new ways to enhance plant freezing tolerance. Members of the serine/threonine protein kinase (CIPK) gene family play important roles in abiotic stress. However, the function of CIPK genes in P. mume remains poorly defined. A total of 16 CIPK genes were first identified in P. mume. A systematic phylogenetic analysis was conducted in which 253 CIPK genes from 12 species were divided into three groups. Furthermore, we analysed the chromosomal locations, molecular structures, motifs and domains of CIPK genes in P. mume. All of the CIPK sequences had NAF domains and promoter regions containing cis-acting regulatory elements of the related stress response. Three PmCIPK genes were identified as Pmu-miR172/167-targeted sites. Transcriptome data showed that most PmCIPK genes presented tissue-specific and time-specific expression profiles. Nine genes were highly expressed in flower buds in December and January, and 12 genes were up-regulated in stems in winter. The expression levels of 12 PmCIPK genes were up-regulated during cold stress treatment confirmed by qRT-PCR. Our study improves understanding of the role of the PmCIPK gene family in the low temperature response in woody plants and provides key candidate genes and a theoretical basis for cold resistance molecular-assisted breeding technology in P. mume.

Метод оцінки впливу екзогенних біостимуляторів на укорінення стеблових живців

Because of creation the optimal rooting conditions, the issues of improving the humidification, letting in the light to plants in the greenhouse, its structural features etc. are relevant. Under the conditions of complying with the main technological requirements, in order to increase the plant rooting efficiency, the use of exogenous biostimulants (plant rooting hormones) becomes particularly important. Objective – to develop and test the method of integrated assessment of the results of rooting of stem cuttings in experiments using exogenous biostimulators. The object of the research – rhizogenic ability of stem cuttings of phytological introduced species. Subject of researches – process of rhizogenesis in connection with the testing of exogenous biostimulators (biologically active substances) on the stem cuttings of hiba arborvitae (Thujopsis dolabrata Sieb. et Zucc.). There were used such methods as literary-analytical, physiological, and comparative, mathematical. research the objective the following tasks were set: 1) to carry out the experiments with the use of the method that involves taking into account the number of rooted stem cuttings; 2) to propose a scale for a quantitative and qualitative evaluation of the results (success) of rooting of stem cuttings; 3) to develop a method for determining the integrated (general) index of rooting of stem cuttings; 4) to carry out a comprehensive study of the rhizogenic capacity of hiba arborvitae using exogenous biostimulants. The application the method of integrated assessment of the influence of exogenous biostimulators on the rhizogenic ability of stem cuttings allows to calculate an integrated (general) index of their rooting for each of the experimental variants. The proposed index takes into account the results of not only quantitative but also qualitative evaluation, which allows identifying the best variants of the use of exogenous biostimulators for the treatment of stem cuttings. According to the results of the conducted research, a 4-point scale is proposed to apply for assessing the quality of rooting, as well as to evaluate the percentage of the results of the rooting of cuttings on a 6-point scale. For an integrated assessment of the effect of exogenous biostimulators on the rooting of stem cuttings of plants of a certain systematic or economic plant group, it is advisable to carry out the experiments in 3 stages. The method for determining the integrated index of rooting is presented for the first time in the final report on the materials of the state scientific topic To research the biological and technological basis of propagation of woody ornamental plants, No. of state registration 0106U0006299 (2006-2008). In the corresponding interpretation, the proposed method can be used in experiments to test different substrates, time of rooting of stem cuttings, methods of their preparation, greenhouse design, lighting, heating, etc., as well as to optimize the technology of care for cuttings during the time of rooting.

First Record of Erysiphe elevata on Plumeria rubra in Taiwan

Plumeria rubra L., native to tropical Central America, is a widely cultivated ornamental woody plant. In two municipalities in northern Taiwan we observed brown discolorations irregularly following veins on the abaxial surface of green or yellowing lower (old) leaves of two outdoor plants of P. rubra. The upper side did not show symptoms or diffuse yellow spots. About 80% of leaves exhibited superficial mycelia and conidiophores typical of a powdery mildew. Specimens collected from a garden plant in Taipei City on 31 May 2018, and from a pot plant in Taoyuan City, Zhongli District, on 7 June 2018, were deposited under the collection numbers R. Kirschner 4647 and 4651 in the National Museum of Natural Science, Taichung, Taiwan (TNM). Fresh specimens were mounted in approximately 10% KOH and observed with light microscopy. The mycelium was hypophyllous, forming irregular patches. Hyphae were hyaline, walls thin, smooth, 3 to 8 μm wide, with hyphal appressoria single or opposite in pairs, nipple shaped or lobed. Conidiophores were 35 to 76 μm long, 7 to 9 μm wide, erect, straight or curved at the base, mostly three-celled, occasionally one- or two-celled. Foot cells were rough at the base, 24 to 35 μm long, 6 to 8 μm wide, with basal septum mostly even with the surface of the supporting hypha. Conidia were solitary, ellipsoidal to cylindrical, smooth, 28 to 35 μm long, 13 to 16 μm wide, and germination was not observed. The specimens were compared with a specimen (R. Kirschner 1945, TNM) of E. elevata on Catalpa sp. (Bignoniaceae), collected in Germany, Frankfurt am Main, Bergen-Enkheim, 18 July 2004. The anamorphic specimens from Catalpa sp. in Germany and P. rubra from Taiwan were morphologically indistinguishable. The internal transcribed spacer (ITS) region of rDNA of both Taiwanese specimens was amplified with the primers ITS1F/ITS4 and sequenced. The 660-bp-long ITS sequences of R. Kirschner et al. 4647 (GenBank MH507182) and 4651 (GenBank MH507183) were 100% identical to each other and 99 to 100% identical to the 10 available sequences of E. elevata in GenBank (Meeboon and Takamatsu 2017), whereas the similarity was 98% or lower for other species. Erysiphe sp. (labeled as E. elevata in GenBank under MF092833) recorded on Plumeria pudica by Suarez et al. (2017) had a similarity of 97% (582/597 bp). The sequence MF092833 contained seven unclear positions (“N”), indicating technically insufficient quality. Because of the high similarity of sequences and anamorph morphology, the specimens on P. rubra from Taiwan are conspecific with E. elevata. It seems to be limited to the lower side of the older leaves, where it forms inconspicuous mycelia so that the brown scribble-like discolorations along the leaf veins are more diagnostic symptoms than the mycelial colonies. Powdery mildew of Plumeria leaves is often reported anecdotally, but confirmed reports are lacking. Recently, Suarez et al. (2017) identified the causative agent as the genus Erysiphe on P. pudica in the United States. Because P. rubra was introduced to Taiwan in the 17th century and the first hybrid in 1967 (Hsueh and Yang 2009), the pathogen may have gone unnoticed for a long time. According to our observation, however, the powdery mildew appears to be less frequent than the recently reported rust Coleosporium plumeriae (Chung et al. 2006) and might have been recently introduced. The fungus may be involved in an accelerated leaf-fall, particularly in connection with additional stress factors such as drought or coinfection with the rust fungus.

Characterization, validation, and cross-species transferability of newly developed EST-SSR markers and their application for genetic evaluation in crape myrtle (Lagerstroemia spp)

Crape myrtle is an important ornamental woody plant, due to its long-lasting midsummer bloom and rich color. However, limited molecular markers on this species hinder the breeding and genetic studies. In this work, 8652 EST-SSRs were identified from L. indica transcriptome data. Di-nucleotide repeats (57.1%) were the most abundant type followed by tri-, tetra-, penta-, and hexa-nucleotide repeats, with the AG/CT motif occurring most frequently. Of the 1200 synthesized primer pairs, 761 EST-SSRs (63.4%) were successfully amplified and 245 EST-SSRs (20.4%) showed polymorphic. High cross-species transferabilities of these markers were observed except in L. speciosa (26.7%). The polymorphic information content (PIC) for each locus ranged from 0.210 to 0.813 with a mean of 0.589, suggesting a high level of informativeness. Using 30 polymorphic EST-SSRs, structure and cluster analyses roughly divided the 73 genotypes into three major groups with some admixtures. This work contributes to the better understanding of the genetic diversity and germplasm resources conservation in Lagerstroemia species. Thus, the newly developed EST-SSRs will provide a valuable tool for genetic analysis, linkage map construction, and marker-assisted selection breeding in crape myrtle.

Somatic embryogenesis from stamen filaments of Aesculus flava Sol. and peroxidase activity during the transition from friable to embryogenic callus

Species of the genus Aesculus are among the most attractive ornamental woody plants. Conventional propagation methods of these species are either inefficient (stem cuttings) or unsuitable for clonal propagation (seeds). The aim of the present study was to develop an efficient protocol for clonal propagation of elite specimens of yellow buckeye (Aesculus flava) by somatic embryogenesis. For this purpose, stamen filaments of yellow buckeye were cultivated on media supplemented with 1, 5 or 10 μM 2,4-dichlorophenoxyacetic acid (2,4-D) combined with 0, 1, 5 or 10 μM 6-furfurylaminopurine (Kin), either under light or dark conditions, for 8 weeks, and then subcultivated on plant growth regulator (PGR)-free medium with 400 mg/l of glutamine. The highest somatic embryo (SE) initiation rates were achieved for the explants cultivated in darkness on medium containing 1 μM 2,4-D + 10 μM Kin during callus induction (CI) phase. Embryogenic calli (EC) were initiated from friable calli, starting from the 7th week of culture initiation, while SEs appeared two weeks later, following a week of subcultivation of the explants on PGR-free medium. EC and SEs were observed only in the explants grown in darkness during CI phase. Minimal duration of CI phase and darkness necessary for SE induction was four weeks, while the highest embryogenic response was achieved when each lasted for 8–10 weeks. Obtained SEs were efficiently multiplied on medium supplemented with 0.05 μM 2,4-D + 5 μM Kin by recurrent somatic embryogenesis. SEs at globular stage of development exhibited the highest capacity for secondary SE regeneration. High germination and conversion rates were attained in cotyledonary-stage SEs cultivated on medium with 0.05 μM 2,4-D + 5 μM Kin, but this phase needs to be further optimised, since the obtained plants failed to acclimatize to greenhouse conditions. During the transition of calli from friable to embryogenic state, total peroxidase (POX) activity significantly decreased, indicating their involvement in the acquisition of embryogenic capacity. The presented protocol is suitable for clonal propagation and genetic transformation of this ornamental species, and POX activity may be used as a marker for SE initiation.

Daily Evapotranspiration of Guzmania ‘Irene’ and Vriesea ‘Carly’ Bromeliads Produced in a Shaded Greenhouse

Bromeliads are important ornamental foliage plants, but until now, their daily water use during production was unknown. Using a canopy closure model developed for container-grown woody ornamental plants, in this study we investigated actual evapotranspiration (ETA) of Guzmania ‘Irene’ and Vriesea ‘Carly’ from tissue-cultured liners grown in 15-cm containers to marketable sizes in a shaded greenhouse. The mean daily ETA of Guzmania ‘Irene’ ranged from 4.02 to 66.35 mL per plant, and the mean cumulative ETA was 16.66 L over a 95-week production period. The mean daily ETA of Vriesea ‘Carly’ varied from 3.98 to 59.89 mL per plant, and the mean cumulative ETA was 15.52 L over the same production period as the Guzmania cultivar. The best-fit models for predicting daily ETA of the two bromeliads were developed, which had correlation coefficients (r2) of 0.79 for Guzmania ‘Irene’ and 0.68 for Vriesea ‘Carly’. The success in the model of ETA for both bromeliads suggested that the canopy closure model was equally applicable to container-grown ornamental foliage plants produced in greenhouse conditions. The daily ETA and cumulative ETA values represent research-based information on water requirements, and, when applied, could improve irrigation practices in bromeliad production. This study also showed that roots per se of the two epiphytic bromeliads were able to absorb water and nutrients from a peat-based container substrate and support their complete life cycles.

Identification and development of microsatellite markers in Hamamelis mollis (Hamamelidaceae).

Premise of the Study Hamamelis mollis (Hamamelidaceae) is a Tertiary relict species endemic to southern China. Polymorphic microsatellite markers were developed to reveal the genetic diversity of this species.Methods and ResultsThe genome of H. mollis was sequenced and de novo assembled into 642,351 contigs. A total of 72,097 paired primers were successfully designed from 80,282 simple sequence repeat (SSR) markers identified in 63,419 contigs. PCR amplification showed that 96 of the 136 synthesized primers could be successfully amplified, and 22 demonstrated polymorphism. The mean number of alleles, levels of observed heterozygosity, and levels of expected heterozygosity were 4.602 ± 0.140, 0.632 ± 0.020, and 0.696 ± 0.010, respectively. The majority of the 96 primer pairs could be amplified in at least one other Hamamelidaceae species, including Distylium myricoides (60), Loropetalum chinense (39), Exbucklandia populnea (24), and E. tonkinensis (24).ConclusionsThese microsatellite loci provide abundant genomic SSR markers to evaluate genetic diversity of this woody ornamental plant.

The value of alien representatives of Prunus L. genus for flowering cherries breeding

Aim. The necessity to search for sources and donors of deficit features for east cherry tree breeding (sakura) and to classify the collection of this promising woody ornamental plant for domestic horticulture determined the conduction of our research. Methods. The availability of some representatives of sakura collection of NDP «Sofiyivka» for breeding was studied with conventional methods, namely, flower color, intensity and duration of flowering, fruit attractiveness, form of a tree crown, vigor and other traits, which determine plant attractiveness for gardens, parks and street plantations, were estimated. Results. Among sakura cultivars which present interest for breeding and are characterized by high ornamental nature along with their adaptability to the conditions of most of the regions in Ukraine, such well-known cultivars as ‘Ama-no-gawa’, ‘Kanzan’, ‘Kiku-shidare-zakura’ and ‘Royal Burgundy’ are to be mentioned. Despite the information concerning the feasibility of spontaneous and the success of artificial intercultivar and interspecific hybridization of Prunus serrulata with other cultivars and other Prunus s. l. genera, at present we have not received P. serrulata hybrids. Conclusions. To enhance the breeding productivity of flowering cherry tree, namely hybridization efficiency of P. serrulata with donors and sources of ornamental traits, it is advisable to involve new initial material on a wide genetic basis not only by economic-valuable features, but also considering the cases of S-genes genetic incompatibility.
 Keywords: Amygdaloideae Arn., Prunus sensu lato, initial material for breeding, gametophytic self-incompatibility, oriental flowering cherries (sakura).

Comprehensive analysis of wintersweet flower reveals key structural genes involved in flavonoid biosynthetic pathway

Wintersweet (Chimonanthus praecox (L.)), with an over-one-thousand-years long history in cultivation, is still a popular ornamental woody plant in China. The tepals of wintersweet flower are waxy in nature and the overall color of the flower is yellow, while the inner tepals range from yellow to red, which makes it an ideal plant to study floral color formation in ornamental shrubs. In our current work, HPLC analysis revealed that the principal pigments in tepals were the metabolite of flavonoids. All the tepals were containing quercetin, kaempferol 3‑O‑rutinoside and rutin while cyanidin‑3‑O‑glucoside and cyanidin‑3‑O‑rutinoside were only found in the in the red tepals. Moreover, we found the rutin as the principal component of all the pigments revealed. As well as in this study, a reference transcriptome library constructed from two varieties H29 and H64 flower. Further, 30 proteins of flavonoid biosynthesis pathway were identified in H29 flower using proteome analysis. Based on these dataset, the flavonoid biosynthesis pathway was also speculated. After quantitative analysis of gene expression, we found that ANS act as an on-off switch for the accumulation of red pigments and had positive correlations with various steps genes of the flavonoid pathway. This expression profiling demonstrates that no gene products compete for common substrates to redirect the metabolic flux in wintersweet. It is also demonstrated that high expression of F3′H would provide sufficient content of the precursor, dihydroquercetin, for both flavonol and anthocyanin biosynthesis. The results help us to deepen and enrich the gene resource of color formation in wintersweet flower, and provide specific breeding strategies for increasing diversity of flower color.

The genetic architecture of floral traits in the woody plant Prunus mume

Mei (Prunus mume) is an ornamental woody plant that has been domesticated in East Asia for thousands of years. High diversity in floral traits, along with its recent genome sequence, makes mei an ideal model system for studying the evolution of woody plants. Here, we investigate the genetic architecture of floral traits in mei and its domestication history by sampling and resequencing a total of 351 samples including 348 mei accessions and three other Prunus species at an average sequencing depth of 19.3×. Highly-admixed population structure and introgression from Prunus species are identified in mei accessions. Through a genome-wide association study (GWAS), we identify significant quantitative traits locus (QTLs) and genomic regions where several genes, such as MYB108, are positively associated with petal color, stigma color, calyx color, and bud color. Results from this study shed light on the genetic basis of domestication in flowering plants, particularly woody plants.