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Работа посвящена усовершенствованию методики культивирования in vitro различных сортов флокса метельчатого. Флокс – ценная декоративная культура. Изучено влияние минерального состава питательной среды на регенерацию микропобегов на стадии микроразмножения. Наиболее высокие значения морфометрических показателей были достигнуты при культивировании на питательной среде MS с добавлением 0,8 мг/л БАП.

A laboratory experiment was performed to evaluate the potential role of H2S on cadmium (Cd) toxicity in Phlox paniculata L. Seeds pretreated with 0.3, 0.6, 0.9, and 1.2 mM NaHS as a donor of H2S for 24 h and subsequently exposed to 100, 200, and 300 μM CdCl2 for 26 days had significantly higher germination rate compared with Cd alone. Meanwhile, 2-year-old seedlings sprayed with 0.3, 0.6, and 0.9 μM NaHS were grown in soil with 0.3, 0.6, and 1.2 mg/kg CdCl2, respectively. We observed that H2S decreased Cd accumulation in leaves and elevated Cd concentration in roots. Cd toxicity in seedlings resulted in a substantial increase in Cd-induced overproduction of malondialdehyde (MDA), Cd accumulation, and electrolyte leakage. Meanwhile, addition of NaHS increased photosynthetic performance compared with Cd alone. Exogenous H2S significantly elevated biomass, improved antioxidant enzyme activities, and reduced ABA content compared with Cd alone. H2S also plays an important role in the ABA signaling pathway during stress. Notably, NaHS promoted Cd uptake by Phlox paniculate L. from soil. The prediction model of H2S for increasing plant resistance and reducing soil Cd pollution was established by factor analysis method based on comprehensive evaluation of plant stress physiology.

During 2015-2018 in the conditions of the Perm region, the seed productivity of 6 varieties Phlox paniculata L. has been studied. The effectiveness of seed production and the success of seed propagation of the phlox depend on the weather conditions strongly, in particular on the air temperature and the amount of precipitation at the corresponding stages of plant development. This is determined by the activity of insect pollinators and effectiveness of pollination. In addition, the large variability of the studied indices in different flox cultivars is probably due to their complex hybrid nature, which reduces their reproductive abilities to varying degrees.

This paper introduces eight ornamental perennial garden escapees that were recorded by the authors of this article on Lucavsala Island, Riga (Latvia) in 2016. Our data on Achillea ptarmica cv. ‘Boule de Neige’, Artemisia ludoviciana, Asclepias syriaca, Campanula lactiflora, Heliopsis helianthoides, Lathyrus latifolius, Phlox paniculata and Rudbeckia hirta contribute to the knowledge about the occurrence of these taxa in wild. All these species are also growing in the collection of ornamental perennials in the Botanical Garden of the University of Latvia. A review of these species in Latvian herbarium collections has been conducted. Five species, Heliopsis helianthoides, Artemisia ludoviciana, Campanula lactiflora, Lathyrus latifolius, Phlox paniculata, were observed for the first time outside cultivation forming relatively stable, reproducing populations. Two species, Achillea ptarmica multiplex cultivar and Rudbeckia hirta, were previously observed in seminatural habitats and, thus, considered as casual aliens at the naturalization stage. One of the species, Asclepias syriaca, was considered a new to Latvia casual alien species with high potential of invasiveness.

The genus Phlox consists of approximately 65 species that include some of the most prevalent ornamental plants in the temperate zone. These popular ornamentals are extremely susceptible to powdery mildew (PM) caused by the biotrophic fungi Golovinomyces magnicellulatus and Podosphaera sp. In this study, we used Phlox paniculata and P. glaberrima to develop a set of laboratory tools to study these pathogens in vitro, including a detached leaf and a micropropagated plantlet bioassay. We assessed pathogen growth under different experimental conditions, which included the use of four different media variations (1/2 MS medium amended with benzimidazole and tetracycline), three ages of pathogen culture (14, 18, and 22 days), three phenological stages of the host tissue (1st, 3rd, and 5th node leaves), placement of inoculum on both leaf surfaces (abaxial and adaxial), and three different inoculation techniques (single spore transfer, colony tapping, colony brushing). Detached P. paniculata leaves were successfully maintained on benzimidazole-amended 1/2 MS medium for up to 3 weeks. For both pathogens, the use of 18-day-old cultures resulted in a higher number of larger, higher sporulating colonies compared with 1-4 and 22-day-old cultures. The adaxial side of 3rd node leaves supported statistically significant more fungal growth compared with the adaxial side of 1st and 5th node leaves. Both pathogens also successfully infected micropropagated plantlets of P. glaberrima. These newly developed tools should facilitate in vitro studies on PM of Phlox and possibly be applicable to other ornamental species attacked by the same fungi.

Visual leaf damage symptoms affect plant and flower development. A variety of physiological leaf symptoms are induced by environmental and growing conditions, including light intensity during cultivation and the nutrition status of the leaves. In the present study, we studied effects of leaf age, leaf ionome, and shade factor during cultivation (20% and 47% shade – under shade nets), on the development of leaf disorders in two cultivars of Phlox paniculata. The leaf ionome of both cultivars changed with leaf age, and varied between cultivars. The percentage of shade applied during cultivation by shade nets, had a minor effect on the leaf ionome, and it did not affect the type and severity of the leaf disorders that developed on the plants, nor the stage of development of their appearance. The ionome of young leaves and mature leaves that were affected by a purple spotting disorder was similar to that of ‘healthy’-looking leaves, demonstrating that this disorder is not related to the nutritional status of the tissue. Our results further excluded leaf age, plant age, plant trimming and shade factor during cultivation (by shade nets) as inducers of the purple spots disorder. This study is first to explore the ionome of Phlox paniculata and in relation to leaf age, physiological leaf disorders and shade factor during cultivation.

The authors present the literature data of the plant's reaction to the pathogenic microorganisms defeat. The information on the development of the powdery mildew on Phlox paniculata L., which negatively affects the decorative and functional state of plants during the vegetation period, is provided. The new and old cultivars of domestic and foreign selection of perennial phlox collection fund of the M.M. Hryshko Flower Decorative Plants Department of the National Botanic Garden of the National Academy of Sciences of Ukraine with varying degrees of defeat by the causative agent of powdery mildew have been studied in the research (such cultivars as 'Fiosin', 'Novinka', 'Holubka' and 'Panianka'). The resistance to defeat was determined in the phase of budding-flowering by the state variety testing method. The plant leaves were taken outdoor according to the method for the laboratory tests. The authors determined the content of flavonoids in terms of routine according to the methodology by V. Yu. Andreeva and G.I. Kalinkina, modified by V.F. Levon. The study was conducted during 2016 and 2017.The resistance of the Phlox paniculata L. plants to the defeat by the powdery mildew pathogen (Erysiphe cichoracearum DC. f. phlogis) was determined. It was found that more than half of all leaves were damaged in the cultivars of 'Fiosin' and 'Novinka' cultivars (4 points), individual leaves were severely affected in 'Holubka' cultivar (2 points), some minor lesions were detected in 'Panianka' cultivar (0˗1 points). The quantitative content of flavonoids in the leaves of investigated plants in the conditions of the Forest-steppe of Ukraine has been defined. In the course of laboratory studies we found that plants of 'Fiosin' cultivar had the highest level of flavonoids (0.982 mg/g), the average level in 'Novinka' cultivar (0.866 mg/g), and in 'Holubka' cultivar (0.842 mg/g). The lowest values were observed in plants of 'Panianka' cultivar (0.764 mg/g). The inverse relation between the content of flavonoids in plants and the resistance to the powdery mildew pathogen of the perspective cultivars of this species has been revealed. The most stable among Phlox paniculata species are the plants of 'Panianka' cultivar, the most vulnerable are the plants of 'Novinka' and 'Fiosin' cultivars. It is recommended to be used as an indicator of resistance to pathogens, powdery mildew in the selection and introduction of quantitative flavonoids.

Phytoplasma strains that belong to group 16SrI (aster yellows phytoplasma group), subgroup A (I-A, North American tomato big bud phytoplasma subgroup) were discovered in diverse plant species in Lithuania. Plants in which the strains were found exhibited symptoms characteristic of infections by phytoplasma. Carrot (Daucus sativus) with carrot proliferation disease exhibited symptoms of proliferation of the crown, chlorosis of young leaves, and reddening of mature leaves. Diseased phlox (Phlox paniculata) exhibited symptoms of virescence and leaf chlorosis. Diseased sea-lavender (Limonium sinuatum) exhibited abnormal proliferation of shoots, chlorosis of young leaves, reddening of mature leaves, and degeneration of flowers. Diseased hyacinth (Hyacinthus orientalis) exhibited chlorosis of leaves and undeveloped flowers. Diseased Aconitum sp. exhibited proliferation of shoots. Phytoplasma-characteristic ribosomal (r) DNA was detected in the plants by use of the polymerase chain reaction (PCR). The rDNA was amplified in PCR primed by primer pair P1/P7 and reamplified in nested PCR primed by primer pair R16F2n/R16R2 (F2n/R2), as previously described (1). The phytoplasmas were classified through restriction fragment length polymorphism (RFLP) analysis of 16S rDNA, amplified in the nested PCR primed by F2n/R2, using single endonuclease enzyme digestion with AluI, MseI, KpnI, HhaI, HaeIII, HpaI, HpaII, RsaI, HinfI, TaqI, and Sau3AI. Collective RFLP patterns indicated that all detected phytoplasma strains were affiliated with subgroup I-A. The 16S rDNA amplified from the phytoplasma (CarrP phytoplasma) in diseased carrot was cloned in Escherichia coli, sequenced, and the sequence deposited in the GenBank data library (GenBank accession no. AF291682). The 16S rDNAs of CarrP and tomato big bud (GenBank acc. no. AF222064) phytoplasmas shared 99.8% nucleotide sequence similarity. Phytoplasmas belonging to group 16SrIII (3), group 16SrV (D. Valiunas, unpublished data), and subgroup I-C in group 16SrI (2,3) occur in Lithuania. This report records the first finding of a subgroup I-A phytoplasma in the Baltic region and expands the known plant host range of this phytoplasma subgroup. References: (1) R. Jomantiene et al. Int. J. Syst. Bacteriol. 48:269, 1998. (2) Jomantiene et al. Phytopathology 90:S39, 2000. (3) Staniulis et al. Plant Dis. 84:1061, 2000.

In vitro regeneration and histological analysis of somatic embryogenesis derived from in vitro leaves were assessed in Phlox paniculata L. The explants were incubated on Murashige and Skoog medium containing 2.26–4.52 μM 2,4-dichlorophenoxyacetic acid (2,4-D) with or without 0.89 μM benzyladenine supplemented with 3% or 9% sucrose and vitamins. The intact leaf blades were cultured in the dark at temperature 22 ± 2◦C. Two Phlox cultivars showed significantly higher regeneration capacity in the in vitro conditions when the cultivation media have been supplemented with 2,4-D at concentrations of 4.52 μM and 3% sucrose. The effect of 2,4-D on somatic embryo induction has been enhanced in presence of cytokinin benzyladenine. In cultivars, the embryogenic structures have been created on calluses derived from leaf sections within 6–9 weeks in culture. Meristematic zones with forming embryogenic structures were mostly localized adjacent to de novo forming tracheal elements in calluses in our experiments. In the absence of tracheal elements, the embryogenic structures have been surrounded by several layers of isodiametric cells. The embryo proper and the suspensor part could be clearly distinguished on the embryogenic structures. The embryogenic potential of cultures has been very high, so that even secondary and tertiary somatic embryos were formed. Within 6–9 weeks in culture, well differentiated embryogenic structures up to torpedo stages were developed. Cultivar ‘Fuji’ exhibited slightly higher embryogenic response in culture than cultivar ‘Starfire’. The cultures maintained their embryogenic potential for about 18 months. Embryogenic structures have been able to convert to complete plants within 3 months.

Physalis alkekengi var. franchetii (Mast.) Makino, known as Chinese lantern, belonging to Solanaceae, is cultivated for its fruits of medicinal value in East Asia (4). Since July 2010, a powdery mildew has been continuously observed on this plant in Shenyang City in northeastern China. More than 90% of the plants in a garden were affected. Symptoms first appeared as circular to irregular white patches, which progressed to abundant mycelial growth on both sides of leaves and young stems. In the middle of August, chasmothecia were formed abundantly, especially on the lower leaf surface. Voucher specimens were deposited in the herbarium of Qingdao Agricultural University (HMQAU10014, 12047, and 12144). Conidiophores produced 2 to 5 conidia in chains with a sinuate outline, followed by 2 to 3 cells. Foot-cells of conidiophores were straight and 46 to 65 × 9 to 11 μm. Conidia were ellipsoid to barrel-shaped, 26 to 32 × 13 to 15.5 μm, lacked distinct fibrosin bodies, and produced germ tubes on the subterminal position. Chasmothecia were amphigenous, also cauligenous, 100 to 140 μm across, and contained 10 to 25 asci. Appendages were mycelioid, 0.5 to 4 times as long as the chasmothecial diameter, and 1- to 3-septate. Asci were short-stalked, 45 to 64 × 26 to 34 μm, and contained two ascospores of 18 to 25 × 12.5 to 15 μm. The internal transcribed spacer (ITS) region of rDNA was amplified (3) and sequenced. The resulting 600-bp sequence was deposited in GenBank (Accession No. KC488260). A GenBank BLAST search of complete ITS sequence showed 100% identity with that of Golovinomyces orontii on P. alkekengi var. franchetii (AB077647 ex Japan) and >99% similarity with those of G. magnicellulatus on Phlox paniculata (AB077621 ex Japan, AF011303 ex the United States, and GU945756 and GU945757 ex Korea). G. orontii is currently confined to the Golovinomyces isolates on Cichorioideae (1). On the basis of the morphological characteristics and ITS sequence data, the fungus was identified as G. magnicellulatus var. magnicellulatus (U. Braun) V.P. Heluta (1). It was already noted that Golovinomyces isolates on Physalis and Phlox are phylogenetically close each other (3). A pathogenicity test was conducted by gently pressing a diseased leaf onto leaves of five healthy Chinese lanterns. Five non-inoculated plants served as controls. Inoculated plants developed symptoms after 8 days, whereas the control plants remained symptomless. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. Powdery mildews of Chinese lantern associated with Golovinomyces species have been known in Korea and Japan (2). A Korean material of Golovinomyces sp. on P. alkekengi var. franchetii was identified as G. magnicellulatus var. magnicellulatus based on morphological characteristics and 100% ITS sequence identity with a Chinese isolate (Shin, unpublished data). To our knowledge, this is the first report of powdery mildew caused by G. magnicellulatus var. magnicellulatus on Chinese lantern in China. References: (1) U. Braun and R. T. A. Cook. Taxonomic Manual of the Erysiphales (Powdery Mildews), CBS Biodiversity Series No.11. CBS, Utrecht, 2012. (2) D. F. Farr and A. Y. Rossman. Fungal Databases. Syst. Mycol. Microbiol. Lab., Online publication, ARS, USDA, retrieved March 22, 2013. (3) S. Matsuda and S. Takamatsu. Mol. Phylogen. Evol. 27:314, 2003. (4) Y. Zheng et al. Phytochem. Anal. 23:337, 2012.

Sphagnum peat moss has been a primary component of soilless potting media for decades; however, concerns over the sustainability of harvesting peat have fostered a search for renewable media components. Anaerobically digested dairy fiber (ADDF), a by-product of methane production, shows promise as an alternative to peat. Herbaceous nursery crops including “Jack Frost” brunnera (Brunnera macrophylla I.M. Johnst), “Moonbeam” coreopsis (Coreopsis verticillata L.), “Whoops-a-Daisy” Shasta daisy (Leucanthemum × superbum Bergmans ex J.W. Ingram), “Kobold Original” liatris (Liatris spicata (L.) Willd.) and “David” phlox (Phlox paniculata L.) were grown in media containing bark-peat-perlite or bark-ADDF-perlite in a 4:2:1 proportion. All leachate was collected from pots to evaluate cumulative nitrogen and phosphate leaching. Brunnera grew to a similar size and quality in both mixes, although brunnera in the bark-ADDF-perlite mix had slightly chlorotic leaf margins. Coreopsis grew to a similar size and quality in both mixes but was slightly etiolated and chlorotic in bark-ADDF-perlite. Shasta daisy grown in bark-ADDF-perlite were larger than those grown in bark-peat-perlite. Both mixes produced similar growth and quality liatris and phlox. More ammonium, nitrate and phosphate were recovered from leachate from bark-ADDF-perlite than from bark-ADDF-perlite.

Phlox is an important genus of herbaceous ornamental plants previously targeted for germplasm development, characterization, and enhancement by the U.S. Department of Agriculture, National Plant Germplasm System. Among Phlox in cultivation, Phlox paniculata is the most widely grown and intensively bred species, but little is known about variation in genome size and ploidy of this species or of related taxa that may be used for germplasm enhancement. The objective of this study was to assess cytotype variation in a diverse collection of cultivars and wild germplasm of P. paniculata (subsection Paniculatae) and of related taxa in subsections Paniculatae and Phlox. The collection included 138 accessions from seven species and two interspecific hybrids. Flow cytometry was used to estimate holoploid (2C) genome sizes and to infer ploidy levels. Chromosome counts were made to calibrate ploidy with genome size for a subset of taxa. Most cultivars were diploid (2n = 2x = 14) and had mean genome sizes that did not vary between subsections Paniculatae (14.33 pg) and Phlox (14.23 pg) although size variation was greater among cultivars within subsection Phlox. Triploid cultivars of P. paniculata, with a mean genome size of 21.36 pg and mitotic chromosome counts of 2n = 3x = 21, were identified. Such triploids suggests previous interploid hybridization within this taxon. Five tetraploid (2n = 4x = 28) cultivars were found in subsection Phlox; all were selections of P. glaberrima ssp. triflora, and had a mean genome size of 25.44 pg; chromosome counts in one of these confirmed they were tetraploid. The putative hybrid Phlox Suffruticosa Group ‘Miss Lingard’ showed an intermediate genome size of 21.21 pg supporting a triploid, hybrid origin of this taxon. Mean 2C genome sizes among wild-collected accessions were similar to values reported for cultivars (Paniculatae = 14.59 pg, Phlox = 14.23 pg), but taxa in subsection Phlox exhibited greater variation that included two tetraploids identified among wild-collected accessions; one, of P. pulchra, had a mean genome size of 26.17 pg, representing the first report of polyploidy in the taxon. This is the first report on genome size for the majority of species in the study. Although genome size could not be used to differentiate taxa in subsections Paniculatae and Phlox, the data provide further insights into cytotype variation of Phlox germplasm useful for plant breeders and systematists.

В статье сделан акцент на возможность внедрения в городское озеленение лишь устойчивых к болезням сортов многолетних флоксов. Приведены данные поражаемости сортов флоксов коллекции ФГБНУ ВСТИСП основными грибными болезнями, вызывающими пятнистости листьев (возбудители Erysiphe cichoracearum, Phyllosticta decussatae, Septoria phlogis, Cercospora omphacodes и Alternaria sp.), сортов Phlox paniculata, Ph. maculata и Ph. subulata). По результатам многолетних исследований, в том числе за благоприятные для развития грибных болезней последние годы, дана оценка устойчивости сортов флоксов к ним. У сортов Ph. subulata со стелющимися побегами при размещении на возвышенных участках у растений не отмечено признаков поражений болезнями. Из флоксов с прямостоячими побегами сорта Ph. maculata (‘Rosalinde’, ‘Shneepyramide’, ‘Delta’) оказались более устойчивыми к болезням по сравнению с большинством сортов Ph. paniculata. Выделены устойчивые, среднеустойчивые и восприимчивые к группе грибных болезней сорта Ph. paniculata. Наиболее устойчивые к болезням сорта этого вида рекомендованы для озеленения в Московской области (‘Creme de la Crème’, ‘David’, ‘Hochgesang’, ‘Peppermint Twist’, ‘Wilhelm Kesselring’, ‘Аня Гаганова’, ‘Батик’, ‘Белый Бирюлевский’, ‘Голубь Мира’, ‘Киев Праздничный’, ‘Розовый Бордюрный’, ‘Успех’). Сделан вывод о допустимости использования в озеленении среднеустойчивых к болезням сортов при соблюдении всех агротехнических мероприятий, ограничивающих развитие болезней., The article focuses on the possibility of introducing into urban landscaping only varieties of perennial phlox resistant to diseases. The data of phloxes damage of the ARHIBAN collection by the main fungal diseases causing leaves blotch, are given (pathogens: Erysiphe cichoracearum, Phyllosticta decussatae, Septoria phlogis, Cercospora omphacodes и Alternaria sp.). Based on the results of many years of research, including those favorable for the development of fungal diseases in recent years, the resistance of phloxes varieties to them has been estimated. When placing the plants Phlox subulata with creeping shoots on elevated areas they had no signs of disease lesions. Of the phlox with erect shoots, the varieties of Ph. maculata (‘Rosalinde’, ‘Shneepyramide’, ‘Delta’) were more resistant to diseases than most Ph. paniculata. The most resistant, medium-resistant and susceptible varieties of Ph. paniculata to the group of fungal diseases were revealed. The most resistant to disease varieties of this species were recommended for landscaping in the Moscow region (‘Creme de la Crème’, ‘David’, ‘Hochgesang’, ‘Peppermint Twist’, ‘Wilhelm Kesselring’ ‘Anya Gaganova’, ‘Batik’, ‘Belyy Biryulevskiy’, ‘Golub’ Mira’, ‘Kiyev Prazdnichnyy’, ‘Rozovyy Bordyurnyy’, ‘Uspekh’). It was concluded that it is possible to use in landscaping medium-resistant varieties to diseases with all the agrotechnical measures limiting the development of diseases., №1 (2018)

В статье поднимается проблема сохранения, поддержания, омоложения и ускоренного размножения растительных объектов биоресурсных коллекций с использованием зеленого черенкования. Описывается постановка интродукционных экспериментов по изучению регенерации травянистых и древесных растений в трех основных направлениях: агротехническое, физиолого-биохимическое и морфологическое. В первом случае основными изучаемыми факторами являются сроки и способы, а также микроэкологические условия, в которых проходит регенерация (влажность, температура воздушной среды и субстрата). Физиологобиохимический аспект касается применения различных ростовых стимуляторов, включая концентрации и экспозиции для обработки неукорененных черенков. Достоверное положительное влияние конкретного ростового вещества в сравнении с контрольной естественной регенерацией может быть доказано с помощью оценки существенности разности выборочных средних по t-критерию. Морфологический аспект изучения регенерации отражает особенности каллюсои ризогенеза. Наиболее глубокий анализ возможен, когда в эксперименте задействованы представители родовых комплексов, виды и сорта различного эколого-географического и генетического происхождения. Подробно описана редко используемая, но весьма информативная классификация типов каллюсои ризогенеза, предложенная Н.Ф. Довбыш, Н.А. Олейник и Г.А. Кудиной (1993), в которой описаны три типа заложения каллюса: валикообразное, очаговое и сплошное, а также пять типов локализации и выноса придаточных корней. Корнеобразование может происходить 1) в зоне узла, 2) из наплывов каллюсной ткани, 3) со стороны почки и листового следа, 4) по всей поверхности междоузлия, а также быть 5) смешанным (из тканей в зоне узла и наплывов каллюсной ткани). На основании многолетнего изучения регенерации кустарниковых и травянистых декоративных растений авторами статьи предложен еще один тип выноса корней по всей поверхности нижнего среза., The paper raises the problem of conservation, maintenance, rejuvenation and accelerated reproduction of plant objects in bioresource collections using green cutting propagation. The authors describe experimental methods of herbaceous and woody plants regeneration study in agricultural, physiological-biochemical and morphological directions. In agricultural direction the main factors are the timing and methods of green cutting, as well as the microecological conditions in which regeneration takes place (humidity, temperature of the air and substrate). The physiological and biochemical aspect concerns the use of various growth stimulants, including concentrations and timing for the treatment of unruly cuttings. The reliable positive effect of the growth stimulants in comparison with control natural regeneration can be proved by the t-criteria. The morphological aspect shows features of callusogenesis and rhizogenesis. The most profound analysis is possible when representatives of generic complexes, species and varieties of various ecological, geographical and genetic origin are involved in the experiment. A highly informative classification of callusogenesis and rhizogenesis proposed by N.F. Dovbysh, N.A. Oleinik and G.A. Kudina (1993) is described in detail; in this classification three types of callus implantation are described: circular, focal and continuous, as well as five types of localization and development of roots. Root formation can occur 1) in the zone of the node, 2) from the callus tissue, 3) from the side of the bud and leaf trail, 4) over the entire surface of the intemode, as well as 5) mixed (from the tissues in the node zone and from callus tissue). Based on the long-term study of the regeneration of shrub and herbaceous ornamental plants, the authors of the paper propose one more type in the entire surface of the lower cut.

Cilem teto prace bylo zjistit ucinnou metodu indukce polyploidie pomoci polyploidizacnich cinidel, kolchicinu a oryzalinu, u diploidniho kultivaru Phlox paniculata 'Fujiyama' (syn. Mt. Fuji, Fuji). Mira regenerace a efektivita polyploidizace (E) byla studovana u dvou metod aplikace chemomutagenů.Phlox paniculata L. patři mezi trvalky, ktere jsou využivany v oblasti mirneho pasma jako okrasne rostliny. Pro odrůdy P. paniculata je charakteristicka jejich mrazuvzdornost, ale citlivost vůci patogenům jako je padli, septoriova skvrnitost listů nebo haďatko. Prvni metody založene na obohaceni stavajiciho sortimentu o odrůdy, ktere jsou přizpůsobive vůci prostředi, se vyvinuly v moderni techniky (jakou je i polyploidizace) s cilem ziskat výchozi slechtitelský material pro dalsi křiženi. Phlox paniculata ma v zakladni diploidni sestavě 14 chromozomů (n = 7). In vitro indukce polyploidie nebyla u tohoto druhu zatim nikde popsana a publikovana.Jako primarni explantaty byly použity intaktni listy z rostlin pěstovaných sest měsiců ve skleniku. Pro iniciaci organogeneze bylo použito modifikovane MS medium. Toto medium obsahovalo 6 μM thidiazuronu (TDZ) a kyselinu indolyloctovou (IAA) v koncentraci 11 μM, 30 g . l-1 sacharozy, vitaminy B5 a 7,5 g . l-1 agaru Sigma. Pro indukci polyploidie byly použity chemomutageny, kolchicin a oryzalin v různých koncentracich. Byly testovany dvě metody osetřeni explantatů (in vitro regenerovane nodalni segmenty výhonů); infiltrace chemomutagenu ze živneho media ("infiltracni metoda") a maceni explantatů v chemickem roztoku mutagenu ("maceci metoda"). Nejvyssi hodnoty frekvence tetraploidů (5 %), mixoploidů (1,67 %) a efektivity polyploidizace (1,25) byly zjistěny u explantatů osetřených 0,2 % kolchicinem po dobu 24 hodin u "maceci metody". Koncentrace 10 μM oryzalinu a 0,2% kolchicinu po dobu 14 dni byly nejucinnějsi pro obdrženi tetraploidů u "infiltracni metody". Výsledky budou využity pro slechtěni dalsich kultivarů druhu P. paniculata L.

Drechsler, D. T., Jeffers, S. N., and Bridges, W. C. 2014. Phytophthora nicotianae can cause both crown rot and foliage blight on Phlox paniculata in South Carolina. Online. Plant Health Progress doi:10.1094/PHP-14-0020. Phytophthora nicotianae is a common pathogen of many herbaceous perennial plants, and this pathogen has been found causing disease on garden phlox (Phlox paniculata) in wholesale nurseries in South Carolina for a number of years. However, the relationship between P. nicotianae and garden phlox has not been studied or reported previously. Using Koch’s postulates and standard inoculation methods for Phytophthora spp., P. nicotianae was found to cause crown rot on P. paniculata when potting medium was infested with colonized vermiculite and to cause foliage blight when aerial parts of the plant were inoculated with an aqueous suspension of zoospores. Foliage blight was more similar to symptoms we observed on garden phlox plants in wholesale nurseries, but crown rot also has been observed previously on plants in these nurseries. The cause of these two diseases was confirmed, but reproduction of Phytophthora foliage blight under experimental conditions was inconsistent. Thus, other factors not yet identified may play a role in the development of Phytophthora foliage blight on garden phlox in nurseries in South Carolina.

Foliar spray applications of plant growth regulators (PGRs) benzyladenine (BA) and dikegulac sodium (DS) on herbaceous perennial liners and transplants were evaluated to determine effects on branching and quality. PGRs were applied three times (main plot): liner (24 h after removal from mist), post-transplant (5 to 7 days after transplant), or both (applications at liner and post-transplant). PGRs (subplots) were applied at concentrations of 400, 800, or 1600 mg·L DS; 600 mg·L BA; or a combination of 400 mg·L DS and 600 mg·L BA (DS/BA). All studies included an untreated control. Sedum spectabile ‘Autumn Joy’ treated with PGRs at both application times had a 100% increase in branching compared with either single application time. Applied post-transplant, 800 mg·L DS, BA, or DS/BA increased branching. Applied at both times, all DS concentrations or BA tripled the number of lateral branches per plant, whereas DS/BA resulted in a 4-fold increase in number of branches. Sedum treated with 1600 mg·L DS at liner, post-transplant, or both application times was shorter than controls; plants sprayed with 1600 mg·L DS at both application times were stunted. Phytotoxicity (yellow, narrow leaves) was present in finished plants treated with 800 or 1600 mg·L DS or DS/BA post-transplant or with 1600 mg·L DS applied both times. Gaillardia aristata ‘Gallo Red’ treated with PGRs at both application times had increased branching compared with plants subjected to a single application. Number of branches was increased by liner application of 400 mg·L DS, post-transplant applications of DS/BA, or applications both times of BA or DS/BA, whereas applications both times of 1600 mg·L DS decreased branching and caused stunting and chlorotic foliage. In application as liners or at both times, all PGRs except 400 mg·L DS caused 16to 33day delays in flowering. Branching of Phlox paniculata ‘Bright Eyes’ was unaffected by application time. Only Phlox treated with BA or 1600 mg·L DS at both application times had increased branches, although plants treated with 1600 mg·L DS were shorter than controls and had phytotoxicity in the form of narrow, yellow leaves. Nepeta racemosa ‘Walker’s Low’ treated with PGRs post-transplant or both application times had more branches than plants treated with PGRs once as liners. Number of branches was increased with BA or 800 mg·L DS applied post-transplant or 1600 mg·L DS, BA, or DS/BA applied both times, but the plants treated with 1600 mg·L DS were stunted and had yellow leaves. Neither BA nor DS affected branching in Delosperma ‘Table Mountain’. Application time did not affect branching in Achillea ‘Moonshine’; only both applications of BA increased the number of branches in Achillea, whereas either single application of 1600 mg·L DS or both applications of 800 or 1600 mg·L DS caused phytotoxicity and stunting. Chemical names used: N-(phenylmethyl)-1Hpurine-6-amine [benzyladenine (BA)], sodium 2,3:4,6-bis-O-(1-methylethylidene)-a-Lxylo-2-hexulofuranosonate (DS) To produce uniform plants, growers of herbaceous perennials control plant growth by using both cultural controls, including plant nutrition, light, and temperature, and chemical controls, i.e., PGRs (Albrecht and Tayama, 1992; Whipker et al., 2006). PGRs can increase branching and improve plant architecture in plants by releasing apical dominance and allowing dormant lateral buds to expand, which results in fuller, well-branched plants (Cline, 1991). However, using PGRs can be challenging, because plants respond in different ways to PGRs depending on species, cultivar, growing conditions, and the PGR used (Gent and McAvoy, 2000). BA, a synthetic cytokinin, is a PGR that increases branching when sprayed on ornamental plants (Latimer and Freeborn, 2008; Martin and Singletary, 1999). The number of branches doubled in Echinacea (L.) Moench ‘White Swan’ and ‘Double Decker’ treated with foliar sprays of 300 or 600 mg·L BA at 2 weeks after transplanting to quart-sized (1.1-L) pots (Latimer and Freeborn, 2008). Of 18 juvenile perennials treated with BA as a foliar spray at rates of 1000, 2000, or 4000 mg·L, 89% had an increase in the number of lateral branches, although no additional branching was seen in the higher two rates as compared with 1000 mg·L (Martin and Singletary, 1999). However, in this study, plants treated with higher rates were more compact and had decreased leaf size. DS has been used as a chemical pinch to prevent elongation in woody plants as well as to increase branching in herbaceous plants. Banko and Stefani (1995) assessed the use of DS on container-grown woody ornamentals. Of the nine species they studied, DS effectively controlled growth in five, producing plants that were more compact and appeared to have denser shoot growth. When 3-yearold field-grown Lavandula·intermedia Emeric ex Loisel. ‘Twickle Purple’ plants were treated with 0.5%, 1.0%, or 2.0% Atrinal (PBI Gordon, Kansas City, MO; containing 20% DS), the numbers of vegetative shoots and inflorescences and oil yield increased significantly compared with controls (Porter and Shaw, 1983). Branching of Gaillardia aristata Pursh. ‘Gallo Yellow’ was increased by foliar sprays of 400 or 800 mg·L DS (Latimer and Freeborn, 2010). However, not all species are responsive to treatment with DS; as referenced previously, Banko and Stefani (1995) found five species responded to DS out of nine studied. PGRs are often applied after transplant, when plants are in active growth and have started to expand. Treating liners (rooted cuttings) before transplant can have significant benefits for growers including reduced time of application and reduced chemical cost. Grossman et al. (2012) reported increases in branching in four of five herbaceous perennials treated with BA before transplant; of these, only two had persistent increases in branching after plants grew to finished size. The question of when to apply growth regulators to achieve increased branching in finished plants is an important one for growers who want to grow out liners to finished, marketable plants. The objective of this study is to examine the effects of application time of DS, BA, or a combination of the two on the growth and branching of herbaceous perennial plants during liner production and grow out of finished plants. Materials and Methods Six herbaceous perennials were studied: Sedum spectabile Boreau ‘Autumn Joy’, Gaillardia aristata Pursh ‘Gallo Red’, Phlox paniculata L. ‘Bright Eyes’, Nepeta racemosa Received for publication 26 Dec. 2012. Accepted for publication 7 May 2013. Partial funding for this project was provided by Fine Americas, Inc. and the Virginia Nursery and Landscape Association. We thank Conrad Fafard, Inc., and Aris Horticulture, Inc. for their support of floriculture research at Virginia Tech. Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product by Virginia Tech and does not imply its approval to the exclusion of other products or vendors that also may be suitable. To whom reprint requests should be addressed; e-mail jlatime@vt.edu. HORTSCIENCE VOL. 48(7) JULY 2013 875 GROWTH REGULATORS

Many vigorous herbaceous perennials need early growth regulation. Treatment at the plug stage could improve early growth control or maintain product size in the plug tray. Concise (uniconazole, Fine Americas, Inc.), is a growth regulator labeled for use on ornamental greenhouse crops in the US. We treated plugs of five herbaceous perennials with a 2-minute dip into 0, 1, 2, 3, 4 or 5 mg/L Concise the day before planting into 1.1-liter pots filled with a peat-lite medium (ornamental grasses were maintained in the plug pots). Plant height was determined at 2 week intervals after treatment (WAT). Concise reduced shoot growth in a linear or quadratic correlation for all crops except Gaillardia × grandiflora ‘Goblin’ which was not affected by the treatments. The ornamental grasses differed in responsiveness with Miscanthus sinensis ‘Gracillimus’ showing little response until 8 WAT while Calamagrostis × acutifolia ‘Karl Foerster’ exhibited a 22% reduction in plant height at 2 WAT with a 1 mg/L Concise dip followed by a 31% height reduction and 26% reduction in shoot dry weight at 12 WAT. A 1 mg/L liner dip of Concise gave significant height reduction of Phlox paniculata ‘David’ and Rudbeckia fulgida var. sullivantii ‘Goldsturm’ through 8 and 10 WAT, respectively. Liner dips are an effective means of growth regulation that can reduce worker contact with the chemical solutions and provide baseline control of vigorous or hard-to-control herbaceous perennial crops.

Gaura lindheimeri Engelm. & Gray ‘Siskiyou Pink’ (gaura) and Phlox paniculata L. ‘David’ (garden phlox) were grown for 5 weeks in substrates irrigated at volumetric water contents (Θ) of 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, or 0.45 m3·m−3 using a capacitance sensor-controlled irrigation system. Volumetric water contents of the substrate measured by the capacitance sensors controlling irrigation were correlated with measurements with a separate handheld meter (r 2 = 0.83) and with volumetric water content set points throughout the study (r 2 > 0.98). Only 3.8 (at an irrigation set point of 0.10 m3·m−3) to 53 L (0.45 m3·m−3) of water was used to irrigate gaura and phlox and 0 to 7.74 L of this water leached out of the substrates. Significant leaching occurred only at Θ set points of 0.40, or 0.45 m3·m−3. Gaura had shorter and fewer branches and reduced dry weight when grown at lower volumetric water contents, but plants irrigated at set points above 0.25 m3·m−3 were large enough to be marketable. Gaura may be grown with capacitance sensor-automated irrigation using water efficiently and minimizing or eliminating leachate and thus nonpoint source pollution.

Phlox paniculata 'John Fanick', a superior selection for Texas landscapes having attractive and long-lasting dense terminal clusters of flowers in shades of red, pink, and white with a dark red eye, has potential as a specialty cut flower crop. The key components affecting quality and post harvest display life of cut flower heads are flower abscission, opening of additional flowers in vase, and maintenance and development of color in flowers during vase life. Addition of gibberellic acid (GA) or prohexadione-Ca (PROHEX) to the holding solution induced abscission of open flowers and inhibited development of flower pigmentation in newly opened flowers. In controls the petal color of flowers turned bluish, but addition of sucrose (SUC) restored the normal pink-white color. In SUC+GA, the flower size increased considerably and the corolla tube elongated, but the flowers exhibited a distinctive light pink color. In SUC+PROHEX, however, the flowers became very large, but the petals remained light bluish or white. In SUC+PROHEX+GA, most of the flowers did not develop color and exhibited perfect white color, although they attained large size and exhibited extended display life. These results point out that the post harvest quality, display life and longevity of cut phlox flowers can be regulated by management of plant growth regulators and sucrose in the vase solution.

Light intensity is often reduced during propagation of nonrooted herbaceous cuttings to minimize temperature and water stress, but the effects of light quantity on rooting and cutting growth have not been quantified for horticulturally important annuals that are vegetatively propagated. Petunia Tiny Tunia ‘Violet Ice’ (Petunia ×hybrida) cuttings were propagated under a daily light integral (DLI) of 1.2 to 3.9 mol·m·d. DLI environments were created using no shade or 30, 55, and 70% woven shade cloth. All cuttings were rooted in a glasshouse with overhead mist, maintained at 25 oC with a vapor pressure deficit of 0.3 kPa. A 12-h photoperiod was delivered using a 9-h natural day extended with light from soft-white fluorescent lamps. Rooting and growth evaluations of cuttings were made 8, 12 and 16 d after stick. Rooting and quality of cuttings increased when the DLI under which they were propagated increased. For example, after 16 d of propagation an increase in DLI from 1.2 to 3.9 mol·m·d decreased cutting shoot length from 6.3 to 4.1 cm, increased average root number from 17 to 36, and increased average length of the longest root from 9.4 to 12.9 cm. Root and shoot dry weight of cuttings harvested after 16 d of propagation increased by 452% and 47%, respectively, as the DLI increased. Therefore, the DLI during propagation should be properly managed to reduce rooting time and produce high quality rooted transplants. INTRODUCTION From 1994 to 2004, the wholesale value of nonrooted cuttings imported by U.S. greenhouse growers increased by 315% (USDA, 2005). In 2004, greenhouse growers in the U.S. imported over 766 million nonrooted cuttings of annuals and perennials with a reported wholesale value of US$55 million. Greenhouse growers have little influence on the stockplant management techniques and the methods employed to harvest, store, and ship these cuttings, but improvements can be made in how nonrooted cuttings are propagated to reduce rooting time, increase rooting quality, and consequently increase profitability. Clearly, to obtain high-quality rooted transplants in the shortest possible time, cuttings must root quickly, uniformly, and abundantly. Vegetative cuttings require a minimum quantity of light to provide the energy for root initiation and development. Light intensities below this minimum result in little or no root growth and development, leading to a delayed crop or rooting failure. Costa and Challa (2002) show that root growth is only affected by current photosynthesis and not by reserves formed previously in leaves. Conversely, too much light can inhibit root formation due to excessive water and temperature stress on the cuttings, and can bleach leaves (Lovell et al., 1972; Joeright et al., 2001; Enfield, 2002). The effects of daily light integral (DLI) or light intensity during propagation of cuttings on rooting percentage, root number and mass, stem elongation and mass, and shoot growth has been studied in several herbaceous and woody species, including Acer palmatum (Behrens, 1988), Gypsophila paniculata (Islam and Willumsen, 2001), Hibiscus sp. (Kachecheba, 1976), petunia cuttings (Cabaleiro and Economou, 1992), Phlox paniculata (Enfield, 2002), Quercus sp. (Zaczek et al., 1999) and Rhododendron (Davis and Potter, 1987). Our objectives were to quantify the effects of DLI on rooting and shoot growth of the popular petunia Tiny Tunia ‘Violet Ice’. Here, we present preliminary results after one replication. Proc. V IS on Artificial Lighting Ed. R. Moe Acta Hort. 711, ISHS 2006 370 MATERIALS AND METHODS Stock Plant Management Petunia Tiny Tunia ‘Violet Ice’ stock plants were maintained in the Plant Science Research Glasshouses at Michigan State University, East Lansing, Mich. (42 oN lat.) at 20 ± 2 oC under a 12-h photoperiod and an average DLI of 11.3 mol·m·d. The photoperiod consisted of a 9-h day completed by day-extension lighting (≈2 μmol·m·s at canopy level) from incandescent lamps. Opaque black cloth was pulled at 1700 HR and opened at 0800 HR everyday. From 0800 to 1700 HR, high-pressure sodium lamps provided a supplemental photosynthetic photon flux (PPF) of ≈150 μmol·m·s at plant height [as measured with a light quantum sensor (Apogee Instruments, Inc., Logan, Utah)] when the outdoor PPF was

Phlox paniculata L. ‘John Fanick’, a superior selection for Texas landscapes, bears attractive and long-lasting clusters of flowers which have several colours, dense deep red, pink and white. We investigated its potential as a cut flower. Vase life was limited by shedding of turgid corollas. Inclusion of 2-chloroethylphosphonic acid (CEPA) in the holding solution, which releases ethylene, considerably hastened corolla abscission, reduced opening of new buds and decreased flower size. Sucrose and thidiazuron (TDZ) both reduced corolla abscission and promoted bud opening during vase life. Petal colour of control flowers turned to bluish, but after sucrose treatment petal colour was maintained. Both TDZ and sucrose counteracted several effects of CEPA (and thus of endogenous and exogenous ethylene during shipping and handling), and greatly improved overall postharvest display life and longevity.

Meristem culture and/or thermotherapy were used for virus elimination from ornamental Phlox paniculata L. (`Blue Boy', `Orange perfection' and `Starfire') mother plants. Shoot tip, leaf, node and flower ovary explants collected from greenhouse-maintained virus free plants were cultured in vitro for shoot initiation. Adventitious shoot initiation was observed on Murashige and Skoog (MS) medium containing the cytokinin BA with or without the auxin NAA. The addition of 0.4 mg·L-1 thiamine, 0.4 mg·L-1 folic acid, and 40 mg·L-1 adenine sulfate to the MS medium did not improve the regeneration rate. Multiplication and rooting were genotype dependent. Blue Boy and Orange Perfection cultivars regenerated the maximum number of shoots from leaf explants. `Blue Boy' leaf explants from in vitro plants had a lower regeneration rate than explants from greenhouse plants. Cultivar `Starfire' had the highest shoot formation with open flower ovary explants and failed to regenerate from leaf explants. In vitro rooting of adventitious shoots in the presence of auxins (IAA, NAA, or IBA) with or without BA was less effective than ex vitro rooting. Chemical names used: 6-benzyladenine (BA); indole-acetic acid (IAA); indole-3-butyric acid (IBA); α-naphthaleneacetic acid (NAA).

Although silicon is not an essential element, it is taken up by plants but is rarely quantified. Therefore, this study quantified the silicon concentration in 10 commonly grown horticultural plants including meadow sage (Salvia ×sylvestris), tickseed (Coreopsis verticillata), garden phlox (Phlox paniculata), New England aster (Symphyotrichum novae-angliae), Chinese astilbe (Astilbe chinensis), coral flower (Heuchera hybrid), garden zinnia (Zinnia elegans), French marigold (Tagetes patula), sweet basil (Basil spp.), and rosemary (Rosmarinus officinalis) using a plant alkaline fusion technique, which involved dry-ashing plant tissue samples and measuring color development with a spectrophotometer. Both zinnia and aster accumulated substantially more silicon from the municipal water source and growing medium (5365 and 4797 mg·kg−1 silicon, respectively) than the other plants evaluated, which had concentrations less than 2500 mg·kg−1 silicon. This study is just one of a few in which the silicon concentration in various horticultural plants has been quantified. Consequently, this may lead to better understanding those plants that will or will not benefit from applications of silicon-based fertilizers to promote cold-hardiness and/or plant resistance to fungal pathogens and insect pests.

Leaf spot was observed on garden phlox (Phlox paniculata) in Yesan, Korea, in 2008. Based on the morphological characteristics of the fungus and the host genus, the isolate was identified as Septoria phlogis. Internal transcribed spacer sequences of rDNA of the isolate confirmed its close affinity to previously known species of Septoria. In 2010 and 2011, the disease was observed in Hoengseong, Korea. This is the first report of Septoria leaf spot on garden phlox in Korea.

Callus was obtained from leaf explants of Phlox paniculata on Murashige and Skoog (MS) basal medium supplemented with 0.5 mg/l BA, 2.0 mg/l IAA and 3% (w/v) sucrose. Somatic embryogenesis was achieved when this callus was subcultured on MS medium supplemented with 1.0–2.0 mg/l BA, 0.25–0.5 mg/l IAA and 3% (w/v) sucrose. The frequency of somatic embryogenesis was greater in callus derived from immature than mature leaf explants. Somatic embryos proliferated rapidly by secondary somatic embryogenesis after transfer to MS medium supplemented with 1.5 mg/l BA, 0.5 mg/l IAA and 3% (w/v) sucrose. Somatic embryos germinated and developed into normal plantlets on half-strength MS medium supplemented with 2% (w/v) sucrose without growth regulator. Embryogenic calli maintained their regeneration capacity for 15 months. About 92% of the somatic embryo-derived plantlets were acclimatized in the greenhouse and successfully transferred to field conditions.

We studied the effects of exogenous salicylic acid on the level of endogenous cytokinins and abscisic and salicylic acids in the tissues of leaves of phloxes contrasting in resistance against the powdery mildew causative agent: susceptible Phlox paniculata L. and resistant Ph. setacea L. Studies were carried out under the conditions of biotic stress. The initial level of salicylic and abscisic acids and cytokinins is the highest in the resistant phlox species. After treatment with salicylic species, the total level of cytokinins and endogenous salicylic acid increased in both species. When the treated phlox species were infected by the powdery mildew causative agent, the level of abscisic and salicylic acids increased in the susceptible Ph. paniculata, while that of cytokinins increased in the resistant Ph. setacea. The role of salicylic acid in the induction of plant defense reactions against phytopathogens is discussed.

Many herbaceous perennials would benefit from additional branching to provide fuller pots in shorter production times. Cyclanilide (Tiberon, OHP, Inc., Mainland, PA, USA), a new product recently labeled in the USA for branching of woody ornamentals, was evaluated on several herbaceous perennials over two seasons. Cyclanilide was applied as a foliar spray to established plants grown in 1.1-L pots filled with a peat-lite medium in late summer. Plant height and number of branches were determined at two week intervals after treatment (WAT). Cyclanilide improved the lateral branching of Phlox paniculata ‘Bright Eyes’ with an eight-fold increase in the number of lateral branches per plant at 6 WAT with 20 mg/L (control 2.2 vs. 20 mg/L 17.8 branches). Higher rates of cyclanilide did not further increase the number of lateral shoots but did increase the phytotoxicity symptoms. Echinacea ‘Ruby Star’ treated with 20 mg/L cyclanilide had twice the basal branches as the untreated control. Lateral branching of Coreopsis ‘Sweet Dreams’ was also doubled by treatment with 20 mg/L cyclanilide. However, even 20 mg/L cyclanilide resulted in unacceptable phytotoxicity damage. Therefore, the study was repeated in the spring with lower rates (0, 5, 10, 15, 20, 25, 30 mg/L cyclanilide) applied to three cultivars of Echinacea, ‘Sunrise,’ ‘Sundown’ and ‘Double Decker’, Phlox paniculata ‘Blue Boy’ and Coreopsis ‘Sweet Dreams’. Only Phlox showed a significant improvement in branching for these spring-planted and spring-treated crops. Although cyclanilide may increase branching of some perennials, phytotoxicity may limit its use for spring production, and there are obviously production issues that affect its efficacy.

Effects of ethephon (2-chloroethylphosphonic acid) were determined on flowering, plant height, and branching of Achillea millefolium L. ‘Weser River Sandstone’, Coreopsis verticillata L. ‘Moonbeam’, Echinacea purpurea Moench ‘Bravado’, Leucanthemum × superbum Bergmans ex. J. Ingram ‘Thomas Killen’, Liatris spicata Willd. ‘Kobold’, Monarda didyma L. ‘Blue Stocking’, Phlox paniculata L. ‘Mt. Fuji’, and Physostegia virginiana Bentham ‘Summer Snow’. Spraying ethephon three times at 1000 mg l−1 (6.92 mM) delayed the flowering of Echinacea, Monarda, and Physostegia by 6, 7 and 9 days, respectively. Ethephon reduced height by 23, 42, 46, 40, or 46% when applied three times at 1000 mg l−1 on Achillea, Echinacea, Leucanthemum, Monarda, or Physostegia, respectively, compared to that of control plants at anthesis. Effects of ethephon on the inflorescence and shoot count per pot varied among species. The number of inflorescences per pot was increased by ethephon application to Achillea (36%), Coreopsis (52%), and Phlox (25%), but was decreased in Echinacea (33%), Leucanthemum (21%), Monarda (62%), and Physostegia (24%). Treatment with ethephon at 1000 mg l−1 caused necrosis of Monarda foliage. Inflorescence diameter of Leucanthemum decreased with increasing ethephon dosage.

In two studies, rooted cuttings of Phlox paniculata L. ‘Ice Cap’ (summer phlox) were cooled for 0, 4, 8, 12, or 16 weeks. Plants were forced in a glasshouse averaging 18 °C nights under extended-day and night-interruption lighting from incandescent lamps providing a minimum of 14 μmol·s−1·m−2 at plant level or continuous lighting from metal halide (HID) lamps providing a minimum of 400 μmol·s−1·m−2 at plant level. The influence of cooling duration on forcing days to flower, flowering stem counts, and flowering stem length was evaluated. Cooling plants promoted longer stems, higher flowering stem yields, and decreased days to flower when forced under long days provided by incandescent lamps, but when forced under HID lamps, days to flower for cooled plants were similar to those of noncooled plants regardless of cooling duration. Phlox forced in extended daylighting flowered in fewer days, had longer stems, and produced more flowering stems than those forced in night-interruption lighting. With continuous HID lighting, stem lengths and stems harvested per plant increased in a linear manner as cooling increased from zero to 16 weeks. Stem lengths ranged from 63.6 cm for noncooled plants to 96.3 cm for those receiving 16 weeks cooling, and flowering stem yields ranged from seven stems per plant for noncooled plants to 13 for those cooled 16 weeks. Phlox forced under HID lights flowered in substantially fewer days and had longer stems than those forced under incandescent lamps.

Received for publication 21 Sept. 2005. Accepted for publication 1 Dec. 2005. Approved for publication by the Director of the Louisiana Agricultural Experiment Station as manuscript 05-38-0593. To whom reprint requests should be addressed; e-mail gholcomb@agcenter.lsu.edu. A Disease of Phlox paniculata Caused by Alfalfa Mosaic Virus Gordon E. Holcomb, Rodrigo A. Valverde, and Dina L. Gutierrez Department of Plant Pathology and Crop Physiology, Louisiana State University AgCenter, Baton Rouge, LA 70803-1720

Phlox (Phlox paniculata cv. Rembrandt) flowers were found to be very sensitive to ethylene. Exposure to ethylene enhanced flower abscission in a concentration-dependent manner, with 50% abscission attained after treatment with 1 μl l−1 ethylene for 12 h. As a result, ethylene also reduced the number of open flowers on the stems throughout their vase life. A 6-h pre-treatment with a volatile inhibitor of ethylene action, 1-methylcyclopropene (1-MCP), completely inhibited the ethylene-induced flower abscission and hence the reduction in the number of open flowers on the stems. 1-MCP was maximally effective in inhibiting the ethylene response at a low concentration (25 nl l−1) and had no visible toxic effects, even at 500 nl l−1. The effects of 1-MCP on flower abscission were comparable to that of a pulse treatment with silver thiosulfate (STS). We therefore suggest that it may serve as an alternative to the commercial treatment of phlox flowers with STS, the latter being an environmental hazard.

Summary A highly efficient shoot regeneration system from greenhouse-grown leaf tisues of Phlox paniculata cvs. Franz Schubert and Prospero was developed. In a preliminary experiment, both TDZ and BA (at 5 μmol/L each) along with 2.5 μmol/L IAA, induced almost a 100 % regeneration frequency for both genotypes, especially when explants were grown without any dark treatment. Moreover, significant differences were observed in regenerability of explants collected from first, second, and third nodes. In a factorial experiment with four BA or four TDZ levels (0.25, 1, 3, and 5 μmol/L) along with three IAA levels (0, 0.5 and 1.0 μmol/L), Franz Schubert, leaf explants exhibited significant differences in shoot organogenesis (mean number of sites of organogenesis/explant, callus development, % explants with>6 shoots/explant) and overall quality of shoot regenerants (mean length of longest shoot, hyperhydration). Results of a principal component analysis indicated that, overall, BA was more effective than TDZ in inducing more shoots and more regeneration sites per explant, and with les callus development. However, hyperhydration (vitrification) of shoot regenerants on media containing 1 μmol/L BA and 0 or 0.5 μmol/L IAA prevented further elongation of these shoots. In another factorial experiment, low levels of both BA (0.5 to 1.5 μmol/L) and IAA (0 to 1 μmol/L) were also investigated. It was observed that all shoot organogenesis occurred along the cut margins of leaf segments and without an intervening callus stage when explants were grown on an MS medium supplemented with 0.5 μmol/L BA and 0.5 μmol/L IAA. Elongation of shoot regenerants was achieved when these were transferred to an MS medium without growth regulators.

The powdery mildew of Phlox (Phlox paniculata) extensively occurred in the experimental farm of Cheongam-myon, Hadong-gun, Gyeongnam province in 2002. Both sides of the leaves and stems were covered with the white fungal spores and mycelia, and then the leaves became brown to dark brown in color, eventually died. The conidiophores on the lesion were observed. Conidia were cylindric in shape, colorless, in size and borne singly on conidiophore. Fibrosin bodies were not observed. Conidiophores were straight with 2-4 cylindric cells, and in size. Appressoria were lobed. Cleistothecia were not formed. This is the first report on powdery mildew of Phlox caused by Oidium sp. in Korea.

China rose (Hibiscus rosa-sinensis L.) is an ornamental plant grown throughout the tropics and subtropics. In June 2011, a China rose plant (sample CV-1) showing bright yellow “aucuba”-type mosaic, mainly at the center of the leaves, was found in a public garden in Caleta de Vélez (Málaga Province, southern Spain). Electron microscope examination of negatively stained preparations from the symptomatic plant revealed the presence of semispherical to bacilliform virus-like particles of 30 to 56 × 16 nm. Sap extracts also reacted positively in double-antibody sandwich (DAS)-ELISA to antiserum against Alfalfa mosaic virus (AMV) (Bioreba AG, Reinach, Switzerland). RNA of this sample was extracted with the RNeasy Kit (Qiagen, Valencia, CA) and tested by reverse-transcription (RT)-PCR with AMV specific primers (2), using AMV and GoTaq Master Mixes (Promega, Madison, WI) for cDNA synthesis and amplification, respectively. After cloning and sequencing, the ~750-bp DNA fragment was confirmed as the coat protein (CP) gene of AMV (GenBank Accession No. HE591387) with the highest nucleotide identity of 96% to AMV isolates belonging to subgroup IIA (e.g., GenBank Accession No. AJ130707). Sap from affected leaves of sample CV-1 was mechanically inoculated onto herbaceous indicator plants (Chenopodium amaranticolor, C. quinoa, and Ocimum basilicum). Both Chenopodium species developed chlorotic local lesions followed by mosaic within 3 days after inoculation, and O. basilicum showed bright yellow mosaic of calico type 2 weeks postinoculation. These symptoms are consistent with those reported for AMV in these hosts (1). Virus infection in the inoculated plants was confirmed by DAS-ELISA and RT-PCR. To gain insight on the prevalence and genetic variability of AMV in China rose, a survey was carried out in nearby locations in the provinces of Málaga (14 samples from Torre del Mar and 5 samples from Rincón de la Victoria) and Granada (12 samples from La Herradura). Leaf samples were analyzed by tissue blot hybridization with an AMV-specific digoxigenin-labeled RNA probe obtained from the RNA 1 of the Spanish isolate Tec1 (3), and only two samples from Torre del Mar tested positive. One of these samples (TM-2) was used to amplify by RT-PCR the AMV CP gene that was cloned and sequenced (GenBank Accession No. HE591386). The highest nucleotide identity of the TM-2 CP gene (98%) was with the subgroup IIB Spanish isolate Tec1, whereas identity with the CV-1 isolate was 95%. Nevertheless, phylogenetic analysis (neighbor-joining method) showed that both CV-1 and TM-2 isolates belong to the recently proposed AMV subgroup IIB (3), which includes the Tec1 isolate and two other isolates from ornamental plants, Phlox paniculata from the United States (GenBank Accession No. DQ124429) and Viburnum lucidum from Spain (GenBank Accession No. EF427449). These results show that AMV subgroup IIB is emerging as a complex cluster of virus isolates that currently are reported to infect only ornamentals. To our knowledge, this is the first report of AMV naturally occurring in China rose. References: (1) G. Marchoux et al. Page 163 in: Virus des Solanacées. Quae éditions, Versailles, 2008. (2) G. Parrella et al. Arch. Virol. 145:2659, 2000. (3) G. Parrella et al. Arch. Virol. 156:1049, 2011.

Six different preemergence herbicides were used with eight different plant species to evaluate weed control efficacy and possible phytotoxicity. The species used were Stachys byzantina C. Koch (lamb's ears), Campanula persicifolia L. (peachleaf bellflower), Achillea millefolium L. ‘Summer Pastel’ (common yarrow), Coreopsis lanceolata L. (Lance coreopsis), Gypsophila pacifica Kom. (baby's breath), Wisteria sinensis Sims (Chinese wisteria), Syringa vulgaris L. (common lilac), Phlox paniculata L. (perennial phlox), Dahlia Cav. x hybrida (garden dahlia). Herbicides were applied to the soil surface at rates of lx and 2x as recommended by the label. The herbicides and rates were as follows: Pennant (Dual) 7.8 Liquid, 4.6, 9.1 kg ai/ha (4, 8 lb ai/A); Gallery 75DF, 1.1, 2.3 kg ai/ha (1, 2 lb ai/A); Ronstar 2G, 4.5, 9.0 kg ai/ha (4, 8 lb ai/A); Rout 3G, 3.4, 6.8, 13.6 kg ai/ha (3, 6, 12 lb ai/A); Surflan AS, 2.3, 4.6 kg ai/ha (2, 4 lb ai/A); and Treflan 5G, 4.5, 9.0 kg ai/ha (4, 8 lbs ai/A). Weed seeds of Setaria glauca (L.) Beauv. (yellow foxtail), Echinochloa crus-galli (L.) Beauv. (barnyardgrass), Poa annua L. (annual bluegrass), Capsella bursa-pastoris (L.) Medik. (shepherdspurse), Senecio vulgaris L. (common groundsel), and Amaranthus retroflexus L. (redroot pigweed) were sown on the soil surface. Two control treatments (no herbicide and no weed seeds applied, or no herbicide but with weed seeds) also were evaluated. Plants were grown in #1 black plastic containers in a medium of clay loam soil, plaster sand and sphagnum peat (1:1:2 by vol). Weed counts at the end of the season indicated that weed control was variable according to the herbicide used. Rout and Ronstar at both the lx and 2x rates controlled over 99% of the weeds (compared to the control treatment with weeds). Weed control for the other herbicides were as follows: Surflan lx = 92%, Surflan 2x = 95%, Pennant lx = 93%, Pennant 2x = 98%, Gallery lx = 35%, Gallery 2x = 43%, Treflan 1x = 88%, and Treflan 2x = 96%. Evaluations also indicated that herbicides utilizing oryzalin resulted in phytoxicity or stunting to Phlox (appearance declined 88% at the 1x rate and 93% at the 2x rate compared to the control treatment), Gypsophila (dry weights for Surflan 1x was 27% less and Surflan 2x was 39% less compared to the control treatment), and Stachys (appearance declined 55% for 1x rate and 60% at the 2x rate). Gallery (isoxaben) resulted in stunting in Stachys (dry weights for Gallery 1x were 75% less compared to control plants and Gallery 2x was 80% less).

The aim of the work was to invstigate viral diseases affecting Phlox paniculata grown in botanical gardens in Lithuania and Ukraine; to identify their agents applying the classical and modern, molecular biology methods. Plants exhibiting symptoms characteristic of viral diseases (plant stunting, leaf malformation, various shaped chlorotic and necrotic spots, ringspots, flower breaking) were collected in Botanical Garden of Vilnius University and N.N. Grishko Kyiv National Botanical Garden. THe causal agents of viral diseases, Alfalfa mosaic virus (AMV) and Tobacco rattle virus (TRV), have been isolated and identified in all investigated Lithuanian and Ukrainian Phlox paniculata samples by the methods of test-plants , electron microscopy, double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA), and reverse transcription polymerase chain reaction (RT-PCR)., Darbo tikslas buvo ištirti Lietuvos ir Ukrainos botanikos soduose auginamų Phlox paniculata virusines ligas ir identifikuoti jų sukėlėjus, pritaikius klasikinius ir molekulinės biologijos metodus. Vilniaus universiteto ir Kijevo N.N. Griško vardo nacionaliniame botanikos soduose buvo surinkti sergantys flioksai, turintys virusinėms ligoms būdingus augalų žemaūgės, lapų deformacijos, įvairios formos chlorotinių ir nekrotinių dėmių ant lapų, žiedų margligės požymius. Liucernos mozaikos (Alfalfa mosaic virus, AMV) ir tabako garbanotosios dryžligės (Tobacco rattle virus, TVR) virusai buvo išskirti ir augalų indikatorių, elektroninės mikroskopijos, imunofermentinės analizės (DAS-ELISA) ir atvirkštinės transkripcijos polimerazės grandininės reakcijos (AT-PGR) metodais identifikuoti visuose Lietuvoje ir Ukrainoje surinktuose pavyzdžiuose.

Een algemeen waarschuwingssysteem voor echte meeldauw in de teelt van zomerbloemen en vaste planten leidt nauwelijks tot minder gewasbespuitingen. Debet hieraan zijn de verschillen tussen meeldauwstammen, gewas- en rasgevoeiligheid en de lage schadedrempel in de sierteelt. Het onderzoek heeft wel geresulteerd in een fungicidentabel, die een compleet en actueel overzicht biedt van toegelaten middelen en hun eigenschappen, inclusief hun milieubelasting. Bij zowel telers als adviseurs is de tabel goed ontvangen

Een algemeen waarschuwingssysteem voor echte meeldauw in de teelt van zomerbloemen en vaste planten leidt nauwelijks tot minder gewasbespuitingen. Debet hieraan zijn de verschillen tussen meeldauwstammen, gewas- en rasgevoeiligheid en de lage schadedrempel in de sierteelt. Het onderzoek heeft wel geresulteerd in een fungicidentabel, die een compleet en actueel overzicht biedt van toegelaten middelen en hun eigenschappen, inclusief hun milieubelasting. Bij zowel telers als adviseurs is de tabel goed ontvangen

Phlox paniculata Linnaeus, Species Plantarum 1: 151. 1753. "Habitat in America septentrionali. Collinson." RCN: 1205. Lectotype (Wherry, Genus Phlox: 120. 1955): Herb. Linn. No. 217.1 (LINN). Current name: Phlox paniculata L. (Polemoniaceae)., Published as part of Jarvis, Charlie, 2007, Chapter 7: Linnaean Plant Names and their Types (part P), pp. 718-782 in Order out of Chaos. Linnaean Plant Types and their Types, London :Linnaean Society of London in association with the Natural History Museum on page 739, DOI: 10.5281/zenodo.291971

Phlox paniculata L., a perennial plant from the family Polemoniaceae, is cultivated as an ornamental in gardens and for cut-flower production. In spring 2003, two types of symptoms were observed in P. paniculata plants grown for cut flowers on a farm in the Var department, France. Some plants showed a mild leaf mosaic while others showed leaf browning and delayed growth. In plants showing mild mosaic, Cucumber mosaic virus (CMV) was detected on the basis of the symptoms exhibited by a range of inoculated plants, the observation of isometric particles (approximately 30 nm) with the electron microscope in crude sap preparations from the infected plants, and the positive reaction in double-antibody sandwich (DAS)-ELISA to polyclonal antibodies raised against CMV (1). In double-immunodiffusion analysis, the five tested isolates were shown to belong to group II of CMV strains. To determine if CMV was responsible for the symptoms observed, one isolate was multiplied in Nicotiana tabacum cv. Xanthi-nc plants after isolation from local lesions on Vigna unguiculata and mechanically inoculated to 12 1-year-old P. paniculata plants. At 3 months post inoculation (mpi), all plants showed mild mosaic and CMV was detected by DAS-ELISA. In sap preparations from P. paniculata plants showing leaf browning symptoms, rod-shaped particles with two distinct sizes of 190 to 210 and 70 to 90 nm long, typical of those associated with tobraviruses, were revealed using electron microscopy. Local lesions typical of Tobacco rattle virus (TRV) were observed after inoculation of N. tabacum cv. Xanthi-nc, Chenopodium amaranticolor, and C. quinoa. Total nucleic acid preparations were prepared from symptomatic plants, and amplicons of the expected size (463 bp) were generated by reverse-transcription (RT)-PCR using primers specific to TRV RNA 1 (4). The nucleotide sequence of one amplicon was 93.6% identical to the sequence of a reference TRV isolate (GenBank Accession No. AJ586803). Twelve 1-year-old P. paniculata plants were mechanically inoculated with an extract of infected tissues from one symptomatic P. paniculata plant. TRV was detected 2 to 6 mpi in apical leaves of all inoculated plants by RT-PCR, although the plants did not express symptoms. Since no other pathogens were detected in the source plants, it is plausible that the lack of symptoms in back-inoculated plants is either due to a long incubation period or an interaction with particular environmental factors such as cold conditions. The survey of approximately 200 plants revealed that approximately 7, 10, and 1% were infected by TRV, CMV, or by both viruses, respectively. CMV and TRV were previously detected in P. paniculata in Latvian SSR and in Lithuania (2,3). These results show that sanitary selection of P. paniculata prior to vegetative propagation should include a screening for TRV and CMV infections. References: (1) J.-C. Devergne et al. Ann. Phytopathol. 10:233, 1978. (2) Y. Ignab and A. Putnaergle. Tr. Latv. S.-Kh. Akad. 118:27, 1977. (3) M. Navalinskiene and M. Samuitiene. Biologija 1:52, 1996. (4) D. J. Robinson. J. Virol. Methods 40:57, 1992.

Phlox paniculata Lyon ex Pursh `Eva Cullum' plants were grown under seven photoperiods following 0 or 15 weeks of 5 °C to determine the effects of photoperiod and cold treatment on flowering. Photoperiods were a 9-hour day extended with incandescent lamps to 10, 12, 13, 14, 16, or 24 hours; an additional treatment was a 9-hour day with a 4-hour night interruption (NI). Noncooled plants remained vegetative under photoperiods ≤13 hours; as the photoperiod increased from 14 to 24 hours, flowering percentage increased from 20 to 89. Flowering of noncooled plants took 73 to 93 days. Flowering percentage was 19, 50, or 100 when cooled plants were held under photoperiods of 10, 12, or ≥13 hours or NI, respectively. Time to flower in cooled plants progressively decreased from 114 to 64 days as the photoperiod increased from 10 to 24 hours. Reproductive cooled plants had at least three times more flowers, were at least 50% taller, were more vigorous, and developed seven or eight more nodes than did noncooled plants. Photoperiod had no effect on height of flowering plants.

Leaves ofPhlox paniculata L. were bombarded with BA-coated gold microprojectiles with the Biolistic PDS/1000-He gene gun. Increasing the concentration of BA from 0.01 to 0.1 mg/μl increased the mean number of adventitious shoots from 7 to 16 shoots per leaf. Bombardment of cotyledons ofPinus pinea L. (Italian stone pine) with BA-coated gold particles significantly reduced the frequency of shoot organogenesis by about 40%. However, induced shoot regenerants from bombarded explants of bothP. paniculata andP. pinea were longer (>1 cm) than those derived from control explants after 3 and 5 wk following bombardment, respectively.

In dit informatieblad van het innovatieproject Topsoil+ worden de productiegegevens van diverse zomerbloemen in het productieseizoen 2005-2006 verstrekt