‘JAFFA’ SWEET ORANGE PLANTS GRAFTED ONTO FIVE ROOTSTOCKS

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ELÍDIO LILIANO CARLOS BACAR

2017-12-01

Full Text Available ABSTRACT Low genetic diversity of citrus scion and rootstock cultivars makes the crop more vulnerable to diseases and pests. The objective of this study was to evaluate the performance of ‘Jaffa’ sweet orange grafted onto five rootstocks over six harvests in subtropical conditions in the north of Paraná state, Brazil. The experiment used a randomized block design, with six replications and two trees per plot, spaced at 7.0 m x 4.0 m. The rootstocks were: ‘Rangpur’ lime, ‘Cleopatra’ and ‘Sunki’ mandarins, ‘Fepagro C-13’ citrange, and ‘Swingle’ citrumelo. The variables evaluated were vigor, yield, and yield efficiency of the trees as well as the physical and chemical characteristics of the fruits. Data were subjected to analysis of variance, complemented by Scott-Knott test at 5% probability. The smallest tree canopy for ‘Jaffa’ sweet orange plants was induced by the ‘Rangpur’ lime rootstock. The trees had the same cumulative yield performance over six seasons for all rootstocks. The best yield efficiency for ‘Jaffa’ sweet orange trees was provided by ‘Fepagro C-13’ citrange rootstock. With regard to fruit quality, no differences were observed among the rootstocks and the ‘Jaffa’ sweet orange fruits met the standards required by the fresh fruit market and the fruit processing industry.

‘JAFFA’ SWEET ORANGE PLANTS GRAFTED ONTO FIVE ROOTSTOCKS

OpenAIRE

ELÍDIO LILIANO CARLOS BACAR; CARMEN SILVIA VIEIRA JANEIRO NEVES; RUI PEREIRA LEITE JUNIOR; INÊS FUMIKO UBUKATA YADA; ZULEIDE HISSANO TAZIMA

2017-01-01

ABSTRACT Low genetic diversity of citrus scion and rootstock cultivars makes the crop more vulnerable to diseases and pests. The objective of this study was to evaluate the performance of ‘Jaffa’ sweet orange grafted onto five rootstocks over six harvests in subtropical conditions in the north of Paraná state, Brazil. The experiment used a randomized block design, with six replications and two trees per plot, spaced at 7.0 m x 4.0 m. The rootstocks were: ‘Rangpur’ lime, ‘Cleopatra’ and ‘Sunk...

Micropropagation of peach rootstocks and cultivars.

Science.gov (United States)

Balla, Ildikó; Mansvelt, Lucienne

2013-01-01

Peach (Prunus persica (L.) Batsch) is one of the most popular stone fruits, commercially produced largely in Mediterranean and, to a lesser extent, in continental climatic conditions. Several breeding programs with different aims release annually large numbers of new cultivars. Micropropagation offers a suitable method to provide the growers of sufficient quantities of rootstocks, as well as of pathogen-free planting material of old and new cultivars.An effective four-step micropropagation procedure for cultivar and rootstock production is described here, based on the use of modified MS and WPM media. The health status of the initial shoot tips is very important, also because the growth and proliferation rate of shoot cultures from virus-infected clones are generally very poor. Proliferation and elongation phases depend on the major macro-elements, as well as the content and ratio of plant growth regulators. It is important to grow the cultures at 22°C, as hyperhydricity may develop at higher temperatures. Although sucrose is the most common carbon source used during proliferation and rooting, for some peach cultivars and rootstocks the replacement of sucrose (10 g/L) with glucose (20 g/L) in the rooting medium improves the rooting and survival rates of plants in the acclimatization phase. The rooting rate of the rootstock "Cadaman" is improved with the chelated form of iron FeEDDHA at 150 mg/L. Rooted plants are acclimatized in greenhouse under high humidity conditions.

Micropropagation of the new apple rootstock ‘G. 814’

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Aline Meneguzzi

Full Text Available ABSTRACT: International breeding programs launched new genetic material of apple rootstocks that in addition to precocity and great yield are resistant to major diseases and soil pests encountered in the largest apple producing regions in Brazil. Given this, there is a necessity for vegetative propagation of these materials for study and possible replacement of existing rootstocks. The objective was to adapt a micropropagation protocol for new apple rootstock ‘G. 814’. In the multiplication phase were evaluated BAP concentrations: 0; 0.5; 1; 2 and 4mg L-1 and in the rooting phase were evaluated IBA concentrations: 0; 0.25; 0.50; 1; 1.5 and 2.5mg L-1. These new results demonstrated that this new rootstock selection can be propagated with this tissue culture adapted protocol. For the successful in vitro propagation of apple rootstock ‘G. 814’ it is indicated the use of 1mg L-1 BAP at multiplication phase and 1.5mg L-1 IBA at rooting phase.

Proteome analysis of interaction between rootstocks and scions in ...

African Journals Online (AJOL)

The main propagation method of rubber tree (Hevea brasiliensis Muell. Arg.) is by grafting. However, the molecular mechanism underlying rootstock-scion interactions remains poorly understood. Identification and analysis of proteins related to rootstock-scion interactions are the bases of clarifying the molecular mechanism ...

The Role of Rootstock in Antioxidant Activity of Citrus Fruit: Comparison of Antioxidant Activity of The Fruits of Two Commercial Citrus Varieties With The Fruits of Four Different Rootstocks

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N . Hemmati

2016-02-01

Full Text Available Introduction: all fruits that called citrus are from rutaceae family and aurantioideae subfamily. This subfamily have more than 33 different genus that only three of its genus (citrus, poncirus and fortunella have economic aspects and in citrus producing country are important. It's reported that orange skin has a phenolic compounds which play a role in natural defense mechanism. Also various compounds of phenolic and antioxidant have a major role in fruit tolerance to stressful condition suh as cold and drought. Metabolites found in citrus fruits have antioxidant properties and it's very useful in pharmaceutical, food and cosmetics industries. Oranges, like other citrus fruits, are an excellent source of vitamin C; Vitamin C is a powerful natural antioxidant. Consumption of foods rich in vitamin C helps the body develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals from the blood. Various factors such as rootstock type can effect on quality and quantity of citrus fruits. Also, the usage of rootstock causes the change in plant characteristics such as flowering time, ripening time, fruit quality and antioxidant characters of the fruits. Other factors except the rootstock such as scion, geographical and climate factors are effective on producing secondary metabolites. Also active substances or secondary metabolites are producing by the conduction of genetic processes, but their production are being effected by other factors obviously. The aim of this study is to investigating the biochemical changes grafted tree fruit that affected by rootstock with study the correlation between grafted tree and rootstock changes. Materials and Methods: This study was done to compare the amount of total phenol, total flavonoids and antioxidant features of fruit flesh and skin with investigating the effect of cultivar and rootstock on these parameters based on completely randomized factorial design with three replications

Scion - rootstock relationships and root behaviour in glasshouse roses

NARCIS (Netherlands)

Fuchs, H.W.M.

1994-01-01

In the Netherlands, the cultivation of cut roses in the glasshouse is commonly carried out yearround. Most cultivars are grown on a rootstock. The first part of this study investigates various rootstocks for their ability to influence production and quality throughout the year. The mutual influence

Sweet orange trees grafted on selected rootstocks fertilized with nitrogen, phosphorus and potassium

OpenAIRE

Quaggio,José Antônio; Mattos Junior,Dirceu; Cantarella,Heitor; Stuchi,Eduardo Sanches; Sempionato,Otávio Ricardo

2004-01-01

The majority of citrus trees in Brazil are grafted on 'Rangpur lime' (Citrus limonia Osb.) rootstock. Despite its good horticultural performance, search for disease tolerant rootstock varieties to improve yield and longevity of citrus groves has increased. The objective of this work was to evaluate yield efficiency of sweet oranges on different rootstocks fertilized with N, P, and potassium. Tree growth was affected by rootstock varieties; trees on 'Swingle' citrumelo [Poncirus trifoliata (L....

Genotype as a New Interspesific Hybrid Rootstock for Stone Fruit

African Journals Online (AJOL)

ADOWIE PERE

this rootstock had good graft compatibility with almond and peach and some apricot. Rooting of micro cutting ... high soil moisture and root suffocation, tolerance to root and collar ... To determine the possibility of proliferation of these rootstocks ...

A comparative analysis of genetic variation in rootstocks and scions of old olive trees - a window into the history of olive cultivation practices and past genetic variation.

Science.gov (United States)

Barazani, Oz; Westberg, Erik; Hanin, Nir; Dag, Arnon; Kerem, Zohar; Tugendhaft, Yizhar; Hmidat, Mohammed; Hijawi, Thameen; Kadereit, Joachim W

2014-05-28

Past clonal propagation of olive trees is intimately linked to grafting. However, evidence on grafting in ancient trees is scarce, and not much is known about the source of plant material used for rootstocks. Here, the Simple Sequence Repeat (SSR) marker technique was used to study genetic diversity of rootstocks and scions in ancient olive trees from the Levant and its implications for past cultivation of olives. Leaf samples were collected from tree canopies (scions) and shoots growing from the trunk base (suckers). A total of 310 trees were sampled in 32 groves and analyzed with 14 SSR markers. In 82.7% of the trees in which both scion and suckers could be genotyped, these were genetically different, and thus suckers were interpreted to represent the rootstock of grafted trees. Genetic diversity values were much higher among suckers than among scions, and 194 and 87 multi-locus genotypes (MLGs) were found in the two sample groups, respectively. Only five private alleles were found among scions, but 125 among suckers. A frequency analysis revealed a bimodal distribution of genetic distance among MLGs, indicating the presence of somatic mutations within clones. When assuming that MLGs differing by one mutation are identical, scion and sucker MLGs were grouped in 20 and 147 multi-locus lineages (MLLs). The majority of scions (90.0%) belonged to a single common MLL, whereas 50.5% of the suckers were single-sample MLLs. However, one MLL was specific to suckers and found in 63 (22.6%) of the samples. Our results provide strong evidence that the majority of olive trees in the study are grafted, that the large majority of scions belong to a single ancient cultivar containing somatic mutations, and that the widespread occurrence of one sucker genotype may imply rootstock selection. For the majority of grafted trees it seems likely that saplings were used as rootstocks; their genetic diversity probably is best explained as the result of a long history of sexual

Evaluation of selected nursery traits in combination rootstocks and variety for Asian pear trees

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Tomáš Nečas

2012-01-01

Full Text Available Evaluation of the nursery traits of rootstocks and varieties is an important tool for optimisation of the fruit orchard plants final growing. The present experiment evaluated the standard and progressive rootstocks for the pear trees in combination with the Asian varieties of P. pyrifolia Nakai. a P. ussuriensis Maxim. in comparison with the control variety ‘Conference’ P. communis L. The evaluation was focused on such properties as affinity, growth of the tree propagated by budding, thickness of the root crown at the rootstock and the root suckering. Their interactions were tested statistically. The highest values of affinity within the nursery were achieved with the following rootstocks: ‘BET’ (96.6%, ‘FOX 11’ (95.5 %, and ‘MA’ (94.4 %. ‘Hosui’ was identified as the variety with the greatest growing capacity, with an average gain of 1238.2 mm. The most supported variety growth was exhibited by the ‘FOX 11’ rootstock, with an average gain of the trees propagated by budding of 1388.8 mm. The growth intensity itself was demonstrated most in the thickness of the root crown of the ‘BET’ (P. betulifolia rootstock, namely 15.8 mm. The rootstock that exhibited the strongest root suckering was also ‘BET’ with 6.2 suckers per rootstock. The identified differences between the varieties and rootstocks were confirmed as statistically significant or even highly statistically significant.

Quality attributes of pistachio nuts as affected by rootstock and deficit irrigation.

Science.gov (United States)

Carbonell-Barrachina, Ángel A; Memmi, Houssem; Noguera-Artiaga, Luis; Gijón-López, María del Carmen; Ciapa, Rafał; Pérez-López, David

2015-11-01

In this work, the influence of two regulated deficit irrigation (RDI) treatments and three different rootstocks on the quality of pistachios was evaluated by analyzing different parameters: morphological analysis, physicochemical analysis and sensory analysis. The results obtained in terms of the choice of rootstock revealed that Pistacia atlantica had increased production yields, nut weight, mineral content, higher intensities of characteristic sensory attributes and a higher degree of consumer satisfaction, than the other rootstocks studied. Moreover, the results established that the application of RDI on pistachio cultivation had no significant influence on production yield, weight, size, colour, water activity or mineral composition. Furthermore, T1 treatment (stem water potential < -1.3 MPa) resulted in higher intensities of characteristic sensory attributes and a greater level of satisfaction among international consumers. These results confirm that the application of deficit irrigation (T1) contributes to an increase in overall product quality. Furthermore, Pistacia atlantica rootstock provided better yield and quality than the other rootstocks studied. © 2014 Society of Chemical Industry.

Yield efficiency for nine apple cultivars grafted on two rootstocks

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João Caetano Fioravanço

Full Text Available ABSTRACT: Currently, using smaller trees is one of the most important trends in apple cultivation. It is expected that reduced size plants produce lower amount of fruit, but with high yield and yield efficiency. The aim of this study was to evaluate the yield efficiency (YE of nine apple tree cultivars, grafted on two rootstocks, from the second to the seventh year after planting. The YE indexes oscillated from one to the other year, regardless of rootstock. Correlations between YE and yield per tree and between YE and trunk cross sectional area (TCSA confirmed that efficiency can be increased by the production increment or by the plant's vigor reduction. The usefulness of cumulative YE (ƩYE is highlighted to compare apple tree cultivars after the third year of production. The highest ƩYE indexes were observed for 'Royal Gala' and 'Baigent', on M-9 rootstock, and for 'Gala Real' and 'Maxi-Gala', on Marubakaido/M-9 rootstock.

A study of the influence of different rootstocks on the vegetative ...

African Journals Online (AJOL)

use

2011-11-23

Nov 23, 2011 ... indicate that vegetative growth with rootstock of bitter almond, which is mostly used, was less than the other tested ..... II international symposium on pistachios and almond. Acta. Hortic. ... Almond rootstock breeding for easy.

A comparative analysis of genetic variation in rootstocks and scions of old olive trees – a window into the history of olive cultivation practices and past genetic variation

Science.gov (United States)

2014-01-01

Background Past clonal propagation of olive trees is intimately linked to grafting. However, evidence on grafting in ancient trees is scarce, and not much is known about the source of plant material used for rootstocks. Here, the Simple Sequence Repeat (SSR) marker technique was used to study genetic diversity of rootstocks and scions in ancient olive trees from the Levant and its implications for past cultivation of olives. Leaf samples were collected from tree canopies (scions) and shoots growing from the trunk base (suckers). A total of 310 trees were sampled in 32 groves and analyzed with 14 SSR markers. Results In 82.7% of the trees in which both scion and suckers could be genotyped, these were genetically different, and thus suckers were interpreted to represent the rootstock of grafted trees. Genetic diversity values were much higher among suckers than among scions, and 194 and 87 multi-locus genotypes (MLGs) were found in the two sample groups, respectively. Only five private alleles were found among scions, but 125 among suckers. A frequency analysis revealed a bimodal distribution of genetic distance among MLGs, indicating the presence of somatic mutations within clones. When assuming that MLGs differing by one mutation are identical, scion and sucker MLGs were grouped in 20 and 147 multi-locus lineages (MLLs). The majority of scions (90.0%) belonged to a single common MLL, whereas 50.5% of the suckers were single-sample MLLs. However, one MLL was specific to suckers and found in 63 (22.6%) of the samples. Conclusions Our results provide strong evidence that the majority of olive trees in the study are grafted, that the large majority of scions belong to a single ancient cultivar containing somatic mutations, and that the widespread occurrence of one sucker genotype may imply rootstock selection. For the majority of grafted trees it seems likely that saplings were used as rootstocks; their genetic diversity probably is best explained as the result of a

Composition and Concentration of Phenolic Compounds of ‘Auksis’ Apple Grown on Various Rootstocks

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Kviklys Darius

2017-06-01

Full Text Available The trial was carried out at the Institute of Horticulture, Lithuanian Research Centre for Agriculture and Forestry in 2013-2015. Cv. ‘Auksis’ was tested on 12 rootstocks: B.396, B.9, M.9, M.26, P 22, P 59, P 61, P 62, P 66, P 67, PB.4, and Pure 1. Accumulation of phenolic compounds depended on fruit yield and average fruit weight. On average, significantly lower concentration among rootstocks occurred when apple trees had abundant yield and fruits were smaller. On average chlorogenic acid constituted 50% and total procyanidins 28% of total phenols in ‘Auksis’ fruits. Flavonoid concentration most depended on rootstock and the highest variation was recorded. More than 50% difference occurred between the highest total flavonoid concentration in apples on PB.4 and the lowest on M.9 rootstocks. Low variability of total procyanidin concentration among rootstocks was observed. Differences between the highest and lowest concentration was 15%. Total concentration of phenolic compounds differed among rootstocks by 29-35% depending on the year. Differences in accumulation of phenolic compounds depended on rootstock genotype but not on yield or fruit weight. PB.4 and P 67 rootstocks had the highest, and M.9, P 62 and M.26 had the lowest concentration of total phenol in ‘Auksis’ fruits

Rootstock Effects on Pistachio Trees Grown in Verticillium dahliae-Infested Soil.

Science.gov (United States)

Epstein, L; Beede, R; Kaur, S; Ferguson, L

2004-04-01

ABSTRACT In a field trial in soil infested with Verticillium dahliae, we compared the yield, growth, incidence of symptoms of Verticillium wilt, and mortality of two interspecific hybrid pistachio tree rootstocks (UCBI and PGII) with the standard rootstocks: the V. dahliae-resistant and susceptible Pistacia integerrima and P. atlantica, respectively. After 10 years, the trees were destructively sampled for V. dahliae in the xylem at the graft union. The results indicate that trees on the (P. atlantica 'KAC' x P. integerrima) hybrid UCBI rootstock grew and yielded as well as those on P. integerrima. Trees on the hybrid PGII yielded the least. Analysis of variance and log-linear models indicate that in soil infested with V. dahliae, three associations significantly affect pistachio nut yield. Rootstock affects scion vigor and extent of infection. Third, the extent of infection and scion vigor are inversely associated. Although trees on the P. integerrima rootstock had the highest ratings in a visual assessment of vigor, 65% were infected with V. dahliae in the trunk in the graft region compared with 73% in P. atlantica and 25% in UCBI. Thus, P. integerrima and UCBI have at least one different mechanism for resistance to V. dahliae.

DRIS norms for 'Valencia' sweet orange on three rootstocks

OpenAIRE

Mourão Filho,Francisco de Assis Alves; Azevedo,João Carlos

2003-01-01

Diagnosis and Recommendation Integrated System (DRIS) applies nutrient ratios instead of the isolated concentration values of each nutrient in interpretation of tissue analysis. The objectives of this research were to establish adequate DRIS norms for 'Valencia' sweet orange irrigated commercial groves budded on three rootstocks and correlate indexes of nutrition balance with yield. Experiments were conducted in São Paulo State, Brazil. Rootstocks Rangpur lime, Caipira sweet orange, and Ponci...

VARYING DEGREE OF GRAFTING COMPATIBILITY BETWEEN CV. CHARDONNAY, MERLOT AND DIFFERENT GRAPEVINE ROOTSTOCKS

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Slavica TODIĆ

2006-02-01

Full Text Available Level of affi nity between grapevine rootstock and Vitis vinifera as scion, quality of reproductive materials and technological actions in grapevine rootstock production process determine success in grapevine rootstock production in large extent. Practical training showed that difference in level of compatibility between grapevine rootstock and grafted Vitis vinifera cultivars are existing. Direct effects of these differences are unequal yield of fi rst class grafted grapevine rootlings. In this paper, level of compatibility in nursery between clones of cv. Chardonnay BCL 75, VCR4 and cv. Merlot R18, MCL 519 and grapevine rootstocks Kober 5BB (Vitis berlandieri x V. riparia, SO4 (V. berlandieri x V. riparia and 41B (Chasselas x V.berlandieri were investigated. The trial was conducted in commercial grapevine nursery located in Velika Drenova, Serbia. As an index of compatibility, grade of high quality grapevine grafted rootlings, dry matter in mature shoots and root system development were used. Grafting was done by `tongue grafting` indoor technique. Stratifi cation was done in sand, on temperature of the stratifi cation material of 26-28oC, and humidity of around 90%. Grafted cuttings were waxed twice: before stratifi cation, and before planting in the nursery. Grafted rootlings were classed in two classes according to regulations of quality, (Yugoslav Offi cial Register, 26/79. Grafted rootlings that did not satisfi ed standard criteria were discarded. Both clones of cv. Chardonnay gave the highest percentage of I class grafted rootlings on grapevine rootstock 41B: clone BCL 75 – 60% and clone VCR4 – 61%. In the same combination, those grapevine grafted rootlings had the highest weight of the root system. Lower percentage of obtained I class grafted rootlings was established on rootstock Kober 5BB, while statistically signifi cantly lower yields were obtained on grapevine rootstock SO4: clone BCL75 – 43% and clone VCR4 – 48%. Dry

Modifications of 'Gold Finger' Grape Berry Quality as Affected by the Different Rootstocks.

Science.gov (United States)

Jin, Zhongxin; Sun, Hong; Sun, Tianyu; Wang, Qingjie; Yao, Yuxin

2016-06-01

Berry qualities of the grafted 'Gold Finger' grapevines were determined to evaluate the impacts of the resistant rootstocks on fruit quality. Compared to the own-rooted vines, berry and cluster weights and skin color were altered by the rootstocks to varying extents. The rootstock of 101-14M maintained TSS/TA and the contents of fructose, glucose, and sucrose, and SO4 decreased these parameters. 101-14M and 3309C increased and reduced the resveratrol content, respectively. SO4, 5BB, and 3309C decreased the total free amino acid content, along with the changes in amino acid composition. The amounts of aroma components were widely altered by the rootstocks. Additionally, a digital gene expression tag profiling revealed that the biological processes were largely altered by 3309C and 101-14M, including sugar, amino acid, and aroma metabolisms. In summary, the rootstock of 101-14M generally maintained berry quality, and SO4, 5BB, and 3309C imparted varying influences on different quality parameters.

Contributions of roots and rootstocks to sustainable, intensified crop production.

Science.gov (United States)

Gregory, Peter J; Atkinson, Christopher J; Bengough, A Glyn; Else, Mark A; Fernández-Fernández, Felicidad; Harrison, Richard J; Schmidt, Sonja

2013-03-01

Sustainable intensification is seen as the main route for meeting the world's increasing demands for food and fibre. As demands mount for greater efficiency in the use of resources to achieve this goal, so the focus on roots and rootstocks and their role in acquiring water and nutrients, and overcoming pests and pathogens, is increasing. The purpose of this review is to explore some of the ways in which understanding root systems and their interactions with soils could contribute to the development of more sustainable systems of intensive production. Physical interactions with soil particles limit root growth if soils are dense, but root-soil contact is essential for optimal growth and uptake of water and nutrients. X-ray microtomography demonstrated that maize roots elongated more rapidly with increasing root-soil contact, as long as mechanical impedance was not limiting root elongation, while lupin was less sensitive to changes in root-soil contact. In addition to selecting for root architecture and rhizosphere properties, the growth of many plants in cultivated systems is profoundly affected by selection of an appropriate rootstock. Several mechanisms for scion control by rootstocks have been suggested, but the causal signals are still uncertain and may differ between crop species. Linkage map locations for quantitative trait loci for disease resistance and other traits of interest in rootstock breeding are becoming available. Designing root systems and rootstocks for specific environments is becoming a feasible target.

Comparative evaluation of oxidative enzyme activities during adventitious rooting in the cuttings of grapevine rootstocks.

Science.gov (United States)

Kose, Cafer; Erdal, Serkan; Kaya, Ozkan; Atici, Okkeş

2011-03-15

This study investigated changes in peroxidase (POX) and polyphenol oxidase (PPO) activities through adventitious rooting in hardwood cuttings of grapevine rootstocks. Three grapevine rootstocks with different propensity to produce adventitious roots were selected: recalcitrant (Ramsey), non-recalcitrant (Rupestris du Lot) and intermediate (99R) cultivars. The averages of root number at 65 days were 96 in Lot, 76 in 99R and 30 in Ramsey. Both enzyme activities characteristically increased before adventitious rooting, regardless of rooting ability of the rootstocks, and then decreased. POX activity increased in Ramsey cuttings at 22 days, in Lot and 99R cuttings at 14 days after planting, and then decreased gradually until 51 days. The highest POX activity was determined in Ramsey rootstock with the highest rooting ability and the lowest activity was determined in the rootstocks with the lowest rooting ability. PPO activity gradually increased in Ramsey rootstock cuttings from 10 days to 22 days, in Lot and 99R cuttings at 14 days, and then decreased until 51 days. A significant correlation was identified between high POX activity and adventitious rooting capability in rootstocks, but the same result was not determined with PPO activity. A recalcitrant rooting variety cannot increase POX activity sufficiently before rooting. Therefore applications that could increase POX activity in stem cuttings during rooting may facilitate increased rooting in such rootstocks. Copyright © 2011 Society of Chemical Industry.

ROOTSTOCK-SCION INTERACTION: 1. EFFECT ON THE YIELD COMPONENTS OF CABERNET SAUVIGNON GRAPEVINE

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ALBERTO MIELE

Full Text Available ABSTRACT The interaction between rootstock, scion and environment can induce different responses to the grapevine physiology. Thus, the aim of this study was to determine the rootstock effect on the yield components of Cabernet Sauvignon (CS grapevine grown in the Serra Gaúcha viticultural region. The experimental design was completely randomized blocks, with 15 treatments, three replicates and ten vines per plot. The results show that all variables evaluated were significantly affected by the year and the rootstock. The CS/Solferino was among other combinations influenced by the year and had higher significant yield/ vine. Indeed, it was higher than that CS/Rupestris du Lot, CS/101-14 Mgt., CS/3309 C, CS/5BB K, CS/161- 49 C, CS/1103 P. and CS/Isabel. The number of clusters/bud, per burst bud and per vine and the weight of clusters were affected by the rootstock as well. Pruning weight/vine, yield/pruning weight, leaf area/vine, leaf area index and leaf area/fresh fruit weight are variables related to the physiology of grapevine which were also affected by the rootstock. In general, rootstocks had adapted well to the environment where the experiment was carried out, giving vigor and high yield to Cabernet Sauvignon grapevine, which means that they may be used by grape growers in this region. However, the choice of the right rootstock depends on various aspects, such as those related to the soil characteristics, climate conditions, grape varieties, and even clones, and production purposes.

Trifoliate hybrids as rootstocks for Pêra sweet orange tree

OpenAIRE

Jorgino Pompeu Junior; Silvia Blumer

2014-01-01

The Rangpur lime (Citrus limonia) has been used as the main rootstock for Pêra sweet orange (C. sinensis) trees. However, its susceptibility to citrus blight and citrus sudden death has led to the use of disease-tolerant rootstocks, such as Cleopatra mandarin reshni), Sunki mandarin (C. sunki) and Swingle citrumelo (C. paradisi x Poncirus trifoliata), which are more susceptible to drought than the Rangpur lime. These mandarin varieties are also less resistant to root rot caused by Phytophthor...

IMPROVEMENTS OF CLONAL MICROPROPAGATION TECHNOLOGY OF APPLE ROOTSTOCKS AT THE STAGE OF INTRODUCTION TO IN VITRO CULTURE

OpenAIRE

Besedina E. N.; Buntsevich L. L.

2015-01-01

The stage of introduction of plantlets to in vitro culture is an important stage of technology of clonal micropropagation of plants. For the purpose of decrease in a share of the plantlets that were lost from an infection and increase of their regeneration ability, sterilizers and antibiotics, effective and safe for apple rootstocks’ plantlets wee allocated, and also favorable terms of introduction to in vitro culture were allocated. As a result of the conducted researches, we have establishe...

Physiological and Nutritional Responses of Two Distinctive Quince (cydonia oblonga mill.) Rootstocks to Boron Toxicity

International Nuclear Information System (INIS)

Eraslan, F.; Kucukyumuk, Z.; Polat, M.; Yildirim, A.

2016-01-01

The effects of excess boron (B) on some physiological and nutritional parameters of two distinctive quince (Cydonia oblonga Mill.) rootstocks were investigated. Throughout the world, B toxicity is a widely faced problem of soil in arid and semi-arid environments. In a greenhouse study, boron was applied at the rates of 0 and 40 mg kg/sup -1/ soil to quince A and quince C rootstocks. Toxicity of B differentially affected studied parameters and rootstocks. Boron toxicity increased B concentrations of both rootstocks however the increase was more pronounced in quince A rootstock. SPAD readings, (SPAD-meter, Minolta 502 Co Ltd., Japan) as a measure of chlorophyll decreased under B toxicity. Boron toxicity increased membrane permeability and anthocyanin in both rootstocks. Al though, there is rootstocks difference, lipid peroxidation (MDA) and proline and TAA (non-enzymatic total antioxidant activity) increased in response to B toxicity. In general, quince C had lower MDA (Malondialdehyde) and TAA but lower level of proline as compared to quince A. Boron toxicity did not affect the concentrations of P, Ca, Zn and Cu however increased B and Mn concentrations. Magnesium (Mg), Mn and Fe concentrations of quince were found higher than that of quince C. Indicating a genotypic effect, quince A and quince C responded to B toxicity differentially. (author)

Grapevine rootstocks shape underground bacterial microbiome and networking but not potential functionality.

Science.gov (United States)

Marasco, Ramona; Rolli, Eleonora; Fusi, Marco; Michoud, Grégoire; Daffonchio, Daniele

2018-01-03

The plant compartments of Vitis vinifera, including the rhizosphere, rhizoplane, root endosphere, phyllosphere and carposphere, provide unique niches that drive specific bacterial microbiome associations. The majority of phyllosphere endophytes originate from the soil and migrate up to the aerial compartments through the root endosphere. Thus, the soil and root endosphere partially define the aerial endosphere in the leaves and berries, contributing to the terroir of the fruit. However, V. vinifera cultivars are invariably grafted onto the rootstocks of other Vitis species and hybrids. It has been hypothesized that the plant species determines the microbiome of the root endosphere and, as a consequence, the aerial endosphere. In this work, we test the first part of this hypothesis. We investigate whether different rootstocks influence the bacteria selected from the surrounding soil, affecting the bacterial diversity and potential functionality of the rhizosphere and root endosphere. Bacterial microbiomes from both the root tissues and the rhizosphere of Barbera cultivars, both ungrafted and grafted on four different rootstocks, cultivated in the same soil from the same vineyard, were characterized by 16S rRNA high-throughput sequencing. To assess the influence of the root genotype on the bacterial communities' recruitment in the root system, (i) the phylogenetic diversity coupled with the predicted functional profiles and (ii) the co-occurrence bacterial networks were determined. Cultivation-dependent approaches were used to reveal the plant-growth promoting (PGP) potential associated with the grafted and ungrafted root systems. Richness, diversity and bacterial community networking in the root compartments were significantly influenced by the rootstocks. Complementary to a shared bacterial microbiome, different subsets of soil bacteria, including those endowed with PGP traits, were selected by the root system compartments of different rootstocks. The interaction

Grapevine rootstocks shape underground bacterial microbiome and networking but not potential functionality

KAUST Repository

Marasco, Ramona; Rolli, Eleonora; Fusi, Marco; Michoud, Gregoire; Daffonchio, Daniele

2018-01-01

The plant compartments of Vitis vinifera, including the rhizosphere, rhizoplane, root endosphere, phyllosphere and carposphere, provide unique niches that drive specific bacterial microbiome associations. The majority of phyllosphere endophytes originate from the soil and migrate up to the aerial compartments through the root endosphere. Thus, the soil and root endosphere partially define the aerial endosphere in the leaves and berries, contributing to the terroir of the fruit. However, V. vinifera cultivars are invariably grafted onto the rootstocks of other Vitis species and hybrids. It has been hypothesized that the plant species determines the microbiome of the root endosphere and, as a consequence, the aerial endosphere. In this work, we test the first part of this hypothesis. We investigate whether different rootstocks influence the bacteria selected from the surrounding soil, affecting the bacterial diversity and potential functionality of the rhizosphere and root endosphere.Bacterial microbiomes from both the root tissues and the rhizosphere of Barbera cultivars, both ungrafted and grafted on four different rootstocks, cultivated in the same soil from the same vineyard, were characterized by 16S rRNA high-throughput sequencing. To assess the influence of the root genotype on the bacterial communities' recruitment in the root system, (i) the phylogenetic diversity coupled with the predicted functional profiles and (ii) the co-occurrence bacterial networks were determined. Cultivation-dependent approaches were used to reveal the plant-growth promoting (PGP) potential associated with the grafted and ungrafted root systems.Richness, diversity and bacterial community networking in the root compartments were significantly influenced by the rootstocks. Complementary to a shared bacterial microbiome, different subsets of soil bacteria, including those endowed with PGP traits, were selected by the root system compartments of different rootstocks. The interaction

Grapevine rootstocks shape underground bacterial microbiome and networking but not potential functionality

KAUST Repository

Marasco, Ramona

2018-01-03

The plant compartments of Vitis vinifera, including the rhizosphere, rhizoplane, root endosphere, phyllosphere and carposphere, provide unique niches that drive specific bacterial microbiome associations. The majority of phyllosphere endophytes originate from the soil and migrate up to the aerial compartments through the root endosphere. Thus, the soil and root endosphere partially define the aerial endosphere in the leaves and berries, contributing to the terroir of the fruit. However, V. vinifera cultivars are invariably grafted onto the rootstocks of other Vitis species and hybrids. It has been hypothesized that the plant species determines the microbiome of the root endosphere and, as a consequence, the aerial endosphere. In this work, we test the first part of this hypothesis. We investigate whether different rootstocks influence the bacteria selected from the surrounding soil, affecting the bacterial diversity and potential functionality of the rhizosphere and root endosphere.Bacterial microbiomes from both the root tissues and the rhizosphere of Barbera cultivars, both ungrafted and grafted on four different rootstocks, cultivated in the same soil from the same vineyard, were characterized by 16S rRNA high-throughput sequencing. To assess the influence of the root genotype on the bacterial communities\\' recruitment in the root system, (i) the phylogenetic diversity coupled with the predicted functional profiles and (ii) the co-occurrence bacterial networks were determined. Cultivation-dependent approaches were used to reveal the plant-growth promoting (PGP) potential associated with the grafted and ungrafted root systems.Richness, diversity and bacterial community networking in the root compartments were significantly influenced by the rootstocks. Complementary to a shared bacterial microbiome, different subsets of soil bacteria, including those endowed with PGP traits, were selected by the root system compartments of different rootstocks. The interaction

Performance of 'Valencia' sweet orange grafted in different rootstocks, Colombia Tropical Lowland. 2001-2013

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Hans Nicolas Chaparro-Zambrano

2015-04-01

Full Text Available 'Valencia' sweet orange is widely cultivated in Colombian tropical lowlands, with low yields and a lack of technology. As a result, nine rootstocks commonly used in tropical zones: 'C-35', 'Carrizo', 'Swingle' citrumelo or CPB 4475, 'Cleopatra', 'Sunki × English', 'Volkamer', 'Webberi' and 'Yuma' were evaluated. The plants were established in 2001 and were evaluated for vegetative growth, fruit yield and quality for 10 years (2004-2013. The obtained results indicated that 'Sunki × English' and 'Volkamer' were the best rootstocks for fruit yield and the worst was 'Yuma'. Furthermore, all of the rootstocks, except 'Yuma', stabilized their height in the last year. In terms of volume, 'Amblycarpa' and 'Cleopatra' were the bigger plants and 'Yuma' was the smallest. In addition, for yield efficiency, 'Yuma' had the best rootstocks, followed by 'Sunki × English'. All of the rootstocks showed a similar fruit quality, except for 'Sunki × English', which obtained the highest total soluble solids/total titratable acids ratio.

Sweet orange trees grafted on selected rootstocks fertilized with nitrogen, phosphorus and potassium

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Quaggio José Antônio

2004-01-01

Full Text Available The majority of citrus trees in Brazil are grafted on 'Rangpur lime' (Citrus limonia Osb. rootstock. Despite its good horticultural performance, search for disease tolerant rootstock varieties to improve yield and longevity of citrus groves has increased. The objective of this work was to evaluate yield efficiency of sweet oranges on different rootstocks fertilized with N, P, and potassium. Tree growth was affected by rootstock varieties; trees on 'Swingle' citrumelo [Poncirus trifoliata (L. Raf. × C. paradisi Macf.] presented the smallest canopy (13.3 m³ in the fifth year after tree planting compared to those on 'Rangpur lime' and 'Cleopatra' mandarin [C. reshni (Hayata hort. ex Tanaka] grown on the same grove. Although it was observed an overall positive relationship between canopy volume and fruit yield (R² = 0.95**, yield efficiency (kg m-3 was affected by rootstocks, which demonstrated 'Rangpur lime' superiority in relation to Cleopatra. Growth of citrus trees younger than 5-yr-old might be improved by K fertilization rates greater than currently recommended in Brazil, in soils with low K and subjected to nutrient leaching losses.

Organic production of tomatoes in the amazon region by plants grafted on wild Solanum rootstocks

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Elaine Aparecida de Paula Farias

2013-08-01

Full Text Available The production of organically grown tomatoes in the Amazonian region of Brazil is difficult due to inherent phytosanitary issues. The objectives of the present investigation were to evaluate the productivity of grafted tomato plants (Solanumlycopersicum cv. Santa Adélia grown organically in Rio Branco, Acre, Brazil, and to assess scion/rootstock compatibility under organic growth conditions. The Solanum species employed as rootstocks were S. gilo (jiló, S. lycocarpum (jurubebão, S. stramonifolium (jurubeba vermelha and S. viarum (joá, while the susceptible S.lycopersicum cultivar Santa Adélia was the scion. Ungrafted tomato plants and tomato grafted on tomato rootstock were employed as controls. The experiment was arranged in a completely randomized block design with six treatments and five repetitions of five plants each. Data were submitted to analysis of variance and the significance of differences between treatments were determined using the Tukey test (P<0.05. All ungrafted tomato plants and those comprising tomato grafted on S.lycopersicum rootstock became infected by brown rot and perished. The total numbers of fruits, numbers of marketable fruits, mean masses of fruits, total productivities and productivities of marketable fruits associated with tomato grafted on S. gilo, S. lycocarpum and S. stramonifolium rootstocks were significantly higher (P<0.05 than the equivalent values obtained with tomato grafted on S. viarum rootstock. S. gilo exhibited the best compatibility index (1.11 of all rootstock/scion combinations studied. It is concluded that tomato grafted on S. gilo, S. lycocarpum and S. stramonifolium rootstocks represent viable alternatives for the production of organic tomatoes in the Amazon region.

YIELD AND QUALITY OF ‘PERA’ SWEET ORANGE GRAFTED ON DIFFERENT ROOTSTOCKS UNDER RAINFED CONDITIONS

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ANTONIO HÉLDER RODRIGUES SAMPAIO

Full Text Available ABSTRACT This study aimed to evaluate, under field conditions, different combinations between ‘Pera’ sweet orange and eight rootstocks: ‘Rangpur’ lime (RL, ‘Volkamer’ lemon (VL, ‘Cleopatra’ mandarin (CM, ‘Sunki Maravilha’ mandarin (SMM, ‘Indio’ and ‘Riverside’ citrandarins, and VL x RL (‘Rangpur’ lime-010 and TH-051 hybrids. The soil water matric potential (?m was characterized for all scion-rootstock combinations at distance of 1.0m from the trunk at the plant row direction and depths of 0.25 m, 0.50 m 0.90 m in the dry and wet seasons. For two years, fruit production parameters and fruit quality were assessed. Differences of Ym among scion-rootstock combinations were observed during the dry season (p=0.05. The lowest Ym values for RL and the highest for TH-051 indicate the existence of different intrinsic mechanisms affecting the water extraction of each scion-rootstock combination. Rootstocks have influenced fruit yield and quality (p=0.05. The best combinations for fruit quality and production were sweet orange grafted on ‘Riverside’, ‘Indio’ and TH-051 rootstocks.

Optimization of medium composition for apple rootstocks

African Journals Online (AJOL)

User

2011-05-02

May 2, 2011 ... Key words: Apple rootstocks, medium composition, multiplication rate, plant growth regulators (PGRs). ... be extrapolated with the same success for another .... Analysis System (SAS) software program (SAS Institute Inc. 1999).

Rootstock Effect on the Tolerance of cv. Hass Avocado Plants to Nacl Stress Efecto del Portainjerto en la Tolerancia de Plantas de Palto cv. Hass al Estrés por NaCl

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Mónica Castro V

2009-09-01

Full Text Available The avocado tree (Persea americana Mill. is one of the species most sensitive to salinity. Since the root system of this species is particularly affected by this type of stress, it is crucial to find a rootstock that is tolerant to saline water irrigation. Plant material from the cv. Hass was grafted on five rootstocks to find possible candidates: the clonal ‘Duke 7’, ‘Nabal’, ‘Degania 117’,’Mexicola’, and ‘Zutano’ seedlings. One year-old plants were placed in 55 L pots; river sand was used as substrate, and the plants were fertilized with a modified Hoagland solution. Vegetative growth and internal nutrient content were compared with control plants with 30 mg L-1 of Cl-, and plants treated with 200 mg L-1 Cl- for 130 days using NaCl in the nutrient solution (5.64 mM. No interaction between NaCl and the rootstocks for the vegetative growth variables was detected neither in K+ internal foliar or root content nor Ca+2 root. With regard to the carbon assimilation rate, the Nabal rootstock showed the highest rates under the NaCl treatment by retaining the highest chloride concentration in the roots and greatly limiting the concentration found in the leaves of the cv. Hass cultivar. It is therefore a promising rootstock for salt tolerance.El palto (Persea americana Mill. es una de las especies más sensibles a la salinidad, debido a que su sistema radical es particularmente afectado por este estrés, es importante identificar un portainjerto tolerante al riego con agua salina. Para encontrar posibles candidatos se utilizó material vegetal del cv. Hass injertado sobre cinco portainjertos, el clonal Duke 7 y los provenientes de semilla, Nabal, Degania 117, Mexícola y Zutano. Plantas de 1 año de edad fueron colocadas en macetas de 55 L, con arena de río como sustrato y fertilizadas con una solución Hoagland modificada. Durante 130 días se comparó el crecimiento vegetativo y los contenidos internos de nutrientes en plantas

Doses of controlled-release fertilizer for production of rubber tree rootstocks

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Renato Luis Grisi Macedo

2012-06-01

Full Text Available This experimental study aimed to evaluate the effects of doses of controlled-release fertilizer (ALL on the development of rubber tree rootstocks. The fertilizer used was Osmocote®, scheduled to be released for 8-9 months and with the following composition: N (15%, P2O5 (9%, K2O (12%, Mg (1%, S (2.3%, B (0.02%, Cu (0.05%, Fe (1%, Mn (0.06%, Mo (0.02% and Zn (0.05%. A randomized block design was used, with four treatments and eight replicates of 20 plants per plot. The controlled-release fertilizer was added to Rendimax Floreira® substrate at doses of 0, 3, 6 and 9 g per liter, and rootstocks were produced in plastic containers with a capacity of two liters of substrate. Three seeds of clone GT 1 were scattered in each container and thinning was performed on day 60, leaving the most vigorous plant only. After the fourth leaf shot from each rootstock, the containers of each treatment were topped, due to compaction, with 300 mL of the relevant fertilizer and substrate mixture. The rootstocks were evaluated at eight months of age as to height, stem diameter (DC 5 cm above root collar, total dry matter, shoot and root dry matter, leaf nutrient levels and percentage of plants suitable for grafting (DC≥1.0 cm. Results revealed that adequate development and nutrition of rootstocks was achieved by using 6 g of controlled-release fertilizer per liter of substrate.

Comprehensive Mineral Nutrition Analysis of Watermelon Grafted onto Two Different Rootstocks

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Yuan Huang

2016-03-01

Full Text Available Grafting is a widely used practice in fruit-bearing vegetables. However, why grafting affects plant growth, fruit yield, and quality, especially from the aspect of mineral nutrition, remains unclear. In this study, watermelon cultivar ‘Zaojia 8424’ was grafted onto bottle gourd ‘Jingxinzhen 1’ (Lagenaria siceraria and pumpkin ‘Qingyanzhen 1’ (Cucurbita maxima × C. moschata. Non-grafted plants were used as the control. Results show that rootstock grafting significantly increases plant growth and single fruit weight of watermelon. Watermelon grafted onto rootstocks, especially pumpkin, exhibits significantly higher root volume, root surface area, and number of root tips and forks in comparison with non-grafted plants. Fruit flesh, rind firmness, and rind thickness were enhanced by grafting. However, fruit soluble solids and taste significantly decreased in plants grafted onto pumpkin. The total uptake (mg ⋅ plant−1 and concentration (mg ⋅ g−1 DW of N, K, Ca, Fe, Mg, and Mn in root, stem, leaf, fruit rind, and flesh were generally higher in grafted plants compared to non-grafted ones, especially for N of pumpkin rootstock-grafted plants. The total uptake of nutrients of plants grafted onto bottle gourd and pumpkin was increased by 30.41% and 49.14% at fruit development stage and by 21.33% and 47.46% at fruit maturation stage, respectively, compared with non-grafted plants. We concluded that watermelon grafting onto suitable rootstocks can increase the uptake of mineral nutrition, especially for N in the pumpkin rootstock grafted plants, thereby affecting plant growth, fruit yield, and quality.

Production of interstocked 'Pera' sweet orange nursey trees on 'Volkamer' lemon and 'Swingle' citrumelo rootstocks

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Girardi Eduardo Augusto

2006-01-01

Full Text Available Incompatibility among certain citrus scion and rootstock cultivars can be avoided through interstocking. 'Pera' sweet orange (Citrus sinensis L. Osbeck nursery tree production was evaluated on 'Swingle' citrumelo (Poncirus trifoliata (L. Raf x Citrus paradisi Macf and 'Volkamer' lemon (Citrus volkameriana Pasquale incompatible rootstocks, using 'Valencia' and 'Hamlin' sweet oranges (Citrus sinensis L. Osbeck, 'Sunki' mandarin (Citrus sunki Hort. ex Tanaka, and 'Cleopatra' mandarin (Citrus reshni Hort. ex Tanaka as interstocks. Citrus nursery trees interstocked with 'Pera' sweet orange on both rootstocks were used as control. 'Swingle' citrumelo led to the highest interstock bud take percentage, the greatest interstock height and rootstock diameter, as well as the highest scion and root system dry weight. Percentage of 'Pera' sweet orange dormant bud eye was greater for plants budded on 'Sunki' mandarin than those budded on 'Valencia' sweet orange. No symptoms of incompatibility were observed among any combinations of rootstocks, interstocks and scion. Production cycle can take up to 17 months with higher plant discard.

Transgene mobilization and regulatory uncertainty for non-GE fruit products of transgenic rootstocks.

Science.gov (United States)

Haroldsen, Victor M; Chi-Ham, Cecilia L; Bennett, Alan B

2012-10-31

Genetically engineered (GE) rootstocks may offer some advantages for biotechnology applications especially in woody perennial crops such as grape or walnut. Transgrafting combines horticultural grafting practices with modern GE methods for crop improvement. Here, a non-GE conventional scion (upper stem portion) is grafted onto a transgenic GE rootstock. Thus, the scion does not contain the genetic modification present in the rootstock genome. We examined transgene presence in walnut and tomato GE rootstocks and non-GE fruit-bearing scions. Mobilization of transgene DNA, protein, and mRNA across the graft was not detected. Though transgenic siRNA mobilization was not observed in grafted tomatoes or walnut scions, transgenic siRNA signal was detected in walnut kernels. Prospective benefits from transgrafted plants include minimized risk of GE pollen flow (Lev-Yadun and Sederoff, 2001), possible use of more than one scion per approved GE rootstock which could help curb the estimated US$136 million (CropLife International, 2011) cost to bring a GE crop to international markets, as well as potential for improved consumer and market acceptance since the consumable product is not itself GE. Thus, transgrafting provides an alternative option for agricultural industries wishing to expand their biotechnology portfolio. Copyright © 2012 Elsevier B.V. All rights reserved.

Rootstock alleviates PEG-induced water stress in grafted pepper seedlings: physiological responses.

Science.gov (United States)

Penella, Consuelo; Nebauer, Sergio G; Bautista, Alberto San; López-Galarza, Salvador; Calatayud, Ángeles

2014-06-15

Recent studies have shown that tolerance to abiotic stress, including water stress, is improved by grafting. In a previous work, we took advantage of the natural variability of Capsicum spp. and selected accessions tolerant and sensitive to water stress as rootstocks. The behavior of commercial cultivar 'Verset' seedlings grafted onto the selected rootstocks at two levels of water stress provoked by adding 3.5 and 7% PEG (polyethylene glycol) was examined over 14 days. The objective was to identify the physiological traits responsible for the tolerance provided by the rootstock in order to determine if the tolerance is based on the maintenance of the water relations under water stress or through the activation of protective mechanisms. To achieve this goal, various physiological parameters were measured, including: water relations; proline accumulation; gas exchange; chlorophyll fluorescence; nitrate reductase activity; and antioxidant capacity. Our results indicate that the effect of water stress on the measured parameters depends on the duration and intensity of the stress level, as well as the rootstock used. Under control conditions (0% PEG) all plant combinations showed similar values for all measured parameters. In general terms, PEG provoked a strong decrease in the gas exchange parameters in the cultivar grafted onto the sensitive accessions, as also observed in the ungrafted plants. This effect was related to lower relative water content in the plants, provoked by an inefficient osmotic adjustment that was dependent on reduced proline accumulation. At the end of the experiment, chronic photoinhibition was observed in these plants. However, the plants grafted onto the tolerant rootstocks, despite the reduction in photosynthetic rate, maintained the protective capacity of the photosynthetic machinery mediated by osmotic adjustment (based on higher proline content). In addition, water stress limited uptake and further NO3(-) transfer to the leaves. Increased

Comparative salinity responses among tomato genotypes and rootstocks

International Nuclear Information System (INIS)

Oztekin, G.B.; Tuzel, Y.

2011-01-01

Salinity is a major constraint limiting agricultural crop productivity in the world. However, plant species and cultivars differ greatly in their response to salinity. This study was conducted in a greenhouse to determine the response of 4 commercial tomato rootstocks, 21 cultivars and 8 candidate varieties to salinity stress. Seeds were germinated in peat and when the plants were at the fifth-true leaf stage, salt treatment was initiated except control treatment. NaCl was added to nutrient solution daily with 25 mM concentration and had been reached to 200 mM final concentration. On harvest day, genotypes were classified based on the severity of leaf symptoms caused by NaCl treatment. After symptom scoring, the plants were harvested and leaf number, root length, stem length and diameter per plant were measured. The plants were separated into shoots and roots for dry matter production. Our results showed that, on average, NaCl stress decreased all parameters and the rootstocks gave the highest performance than genotypes. Among all rootstocks, three varieties (2211 and 2275) and ten genotypes (Astona, Astona RN, Caracas, Deniz, Durinta, Export, Gokce, Target, Yeni Talya and 144 HY) were selected as tolerant with slight chlorosis whereas the genotype Malike was selected as sensitive with severe chlorosis. Candidate varieties 2316 and 1482 were the most sensitive ones. Plant growth and dry matter production differed among the tested genotypes. However no correlation was found between plant growth and dry matter production. Rootstock Beaufort gave the highest shoot dry matter although Heman had highest root dry matter. Newton showed more shoot and root dry matter than other genotypes. It is concluded that screening of genotypes based on severity of symptoms at early stage of development and their dry matter production could be used as a tool to indicate genotypic variation to salt stress. (author)

Trifoliate hybrids as rootstocks for Pêra sweet orange tree

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Jorgino Pompeu Junior

2014-03-01

Full Text Available The Rangpur lime (Citrus limonia has been used as the main rootstock for Pêra sweet orange (C. sinensis trees. However, its susceptibility to citrus blight and citrus sudden death has led to the use of disease-tolerant rootstocks, such as Cleopatra mandarin reshni, Sunki mandarin (C. sunki and Swingle citrumelo (C. paradisi x Poncirus trifoliata, which are more susceptible to drought than the Rangpur lime. These mandarin varieties are also less resistant to root rot caused by Phytophthora, and the Swingle citrumelo showed to be incompatible with the Pêra sweet orange. In search of new rootstock varieties, this study aimed at assessing the fruit precocity and yield, susceptibility to tristeza and blight and occurrence of incompatibility of Pêra sweet orange trees grafted on 12 trifoliate hybrids, on Rangpur lime EEL and Goutou sour orange, without irrigation. Tristeza and blight are endemic in the experimental area. The Sunki x English (1628 and Changsha x English Small (1710 citrandarins and two other selections of Cleopatra x Rubidoux provided the highest cumulative yields, in the first three crops and in the total of six crops evaluated. The Cleopatra x Rubidoux (1660 and Sunki x Benecke (1697 citrandarins induced early yield, while the Cravo x Swingle citromonia and C-13 citrange induced later yield. None of the rootstock varieties caused alternate bearing. Pêra sweet orange trees grafted on Swingle citrumelo, Cleopatra x Swingle (1654 citrandarin and on two selections of Rangpur lime x Carrizo citrange showed bud-union-ring symptoms of incompatibility. None of the plants presented symptoms of tristeza or blight.

Apple tree production in Italy: rootstocks, cultivars, fertilization, and irrigation

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Giovambattista Sorrenti

2012-11-01

Full Text Available Italy is one of the main apple producers in Europe, primarily intended for fresh consumption, both in the domestic and foreign markets. Fruit yield and quality depends on the cultivar, rootstock, and management practices, such as the fertilization and irrigation adopted in the orchard. This review aims at reporting the main apple cultivars and rootstocks, the management of fertilization and irrigation, as well as their adaptation to apple tree orchards in Italy. The programs for genetic improvement carried out in this country involved the selection of apple tree cultivars and rootstocks which enable a high fruit yield and quality, in order to meet the requirements from the consumer market. In the fertilization and irrigation management, nutrients and water are supplied in amounts next to the actual need of the plants, providing an adequate nutrition, a satisfactory yield, and high quality fruits, besides preventing, whenever possible, nutrients and water losses in the environment.

Effects of rootstocks on fruit yield and some quality traits of watermelon (Citrullus lanatus

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Rana Kurum

2017-12-01

Full Text Available In this study the effects of rootstocks on watermelon fruit quality and yield were investigated by comparing grafted plants with non-grafted and self-grafted ones in open field conditions in over two consecutive years (2013-2014. The watermelon cultivar Crimson Tide was grafted onto Ferro RZ, Maximus, Nun 9075, RS 841, No:3, Strong Tosa and TZ 148 rootstocks. Non-grafted and self-grafted plants were used as control. Grafting increased the average fruit yield between 17.45% and 52.56% compared to non-grafted treatment. It was concluded that among the tested rootstocks No:3 along with Nun 9075 and TZ 148 rootstocks can be advised due to the increase in fruit yield, total soluble solids and taste panel test values and that the use of grafted plants can be advantageous alternative in watermelon production for producers.

Effects of grafting with pumpkin rootstock on carbohydrate metabolism in cucumber seedlings under Ca(NO3)2 stress.

Science.gov (United States)

Xing, Wen-wen; Li, Lin; Gao, Pan; Li, He; Shao, Qiao-sai; Shu, Sheng; Sun, Jin; Guo, Shi-rong

2015-02-01

This study investigated the effects of grafting on the carbohydrate status and the enzymes of carbohydrate metabolism in self-grafted and grafted cucumber seedlings using the salt-tolerant pumpkin rootstock 'Qingzhen 1' (Cucurbita maxima × Cucurbita moschata) under 80 mM Ca(NO3)2 stress for 6 d. The growth of self-grafted seedlings was significantly inhibited after the treatment of Ca(NO3)2 stress, whereas the inhibition of growth was alleviated in pumpkin rootstock-grafted seedlings. Ca(NO3)2 stress increased the contents of the total soluble sugar, sucrose and fructose, but decreased the starch content in rootstock-grafted leaves. However, compared with self-grafted plants, rootstock-grafted seedlings were observed with a higher content of sucrose and total soluble sugar (TSS) under salt stress. Rootstock-grafted seedlings exhibited higher activities of acid invertase (AI), neutral invertase (NI) and phosphate sucrose synthase (SPS) of sucrose metabolism in leaves than that of self-grafted seedlings under salinity. Moreover, the activities of fructokinase (FK), hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) of glycolysis were maintained at a higher level in leaves of rootstock-grafted seedlings after Ca(NO3)2 stress. Additionally, rootstock-grafting decrease the high percentage enhancement of key enzymes gene expression in glycolysis in the scion leaves of cucumber seedlings induced by salt stress. These results suggest that the rootstock-grafting improved salt tolerance, which might play a role in elevated sucrose metabolism and a glycolytic pathway regulated by the pumpkin rootstock. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

Evaluation of the Tolerance of Some Citrus Rootstocks to Citrus Nematode in Greenhouse (Tylenchulus semipenetrans

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Y. Mohammad Alian

2018-02-01

Full Text Available Introduction: Citrus nematode is one of the most important damaging nematodes of citrus trees, spreading widely in most areas under citrus planting causing dieback, the gradual decline of trees and crop decrease in citrus orchards. Eighty citrus cultivars and species are sensitive to this nematode. From other nematode hosts, we can refer to olive, fig, medlar, persimmon, pear and grapevine. Surveys Full filled in Mazandaran province is indicative of the widespread of this nematode in citrus horticulture and the level of infection in some samples is so high, thus it is necessary to use different ways of controlling this parasite. Materials and Methods: This research was carried out for 2 successive years and the reaction of sin citrus rootstocks including Citromelo, Poncirus, Sour Orange, Bakraee, Rough lemon and Off-type to citrus nematode under controlled conditions in the greenhouse was evaluated. Three months years old plants of this rootstock Were planted in completely random design with 5 replications in pots containing the population of 40 larvae per cubic centimeter of soil and after six months, the level of infection of roots was investigated and then the most tolerable rootstock for nematode was introduced on the basis of the least population of young females and adult females injected in one gram of root volume. Results and Discussion: Experiment results on the basis of LSD test in two successive years indicated that there is a meaningful statistical difference between Citrumelo and poncirus Poncirus with the least population of nematode of adult female on the root and other treatments the results show that sour orange and off-type rootstocks are the most sensitive to citrus nematode, poncirus Poncirus and Citrumelo are the most tolerable to nematode Bakraee and Rough lemon are in the biotype group with average tolerance (relatively sensitive to citrus nematode. Purpose of this research is to assess the sensitivity level of six citrus

Apple endophytic microbiota of different rootstock/scion combinations suggests a genotype-specific influence

Science.gov (United States)

The present study described the microbiota associated with three apple varieties, ‘Royal Gala’, ‘Golden Delicious’, and ‘Honey Crisp’, and two rootstocks, M.9, and M.M.111. The objectives were to 1) determine if the microbiota differs in different rootstocks and apple varieties, and 2) determine if...

The vigour of glasshouse roses : scion - rootstock relationships : effects of phenotypic and genotypic variation

NARCIS (Netherlands)

Vries, de D.P.

1993-01-01

Glasshouse roses commonly are combination plants, consisting of a scion variety and a rootstock of different genotypes. In this study, various environmental and genotypic factors have been investigated that influence the vigour of rootstocks and scion varieties, separately and in graft

Rootstock effects on pistachio trees grown in Verticillium dahliae-infested soil

OpenAIRE

Epstein, Lynn; Beede, R; Kaur, S; Ferguson, L

2004-01-01

In a field trial in soil infested with Verticillium dahliae, we compared the yield, growth, incidence of symptoms of Verticillium wilt, and mortality of two interspecific hybrid pistachio tree rootstocks (UCBI and PGII) with the standard rootstocks: the V dahliae-resistant and susceptible Pistacia integerrima and P. atlantica, respectively. After 10 years, the trees were destructively sampled for V dahliae in the xylem at the graft union. The results indicate that trees on the (P. atlantica '...

Monitoring the viability of citrus rootstocks seeds stored under refrigeration

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Sérgio Alves de Carvalho

2013-03-01

Full Text Available The citrus nursery tree is produced through the bud grafting process, in which rootstock is usually grown from seed germination. The objective of this research was to evaluate, in two dissimilar environmental conditions, the viability and polyembryony expression of five citrus rootstocks seeds stored in different periods under refrigeration. The rootstock varieties evaluated were: Rangpur lime (Citrus limonia Osb. cv. Limeira, Trifoliate orange (Poncirus trifoliata Raf. cv. Limeira, Citrumelo (P. trifoliata x C. paradisi Macf. cv. Swingle, Sunki mandarin (C. sunki Hort. ex Tanaka and Volkamer lemon (C. volkameriana Ten. & Pasq. cv. Catania 2. The experimental design was the randomized blocks in a 11 x 5 x 2 factorial scheme, evaluating from time zero to the tenth month of storage, the five varieties of rootstock in two environments: germination and growth B.O.D type chamber (Biological Oxygen Demand - Eletrolab Brand Model FC 122 at 25 °C; and greenhouse seedbed with partial temperature control (22 °C to 36 °C and humidity control (75-85%. The plot had 24 seeds in four replicates, using trays with substrate in greenhouse and Petri dishes with filter paper in B.O.D. chamber. The seed germination rate and polyembryony expression were evaluated monthly. It was concluded that Trifoliate and Citrumelo Swingle seeds can be stored for up to seven months, while Volkamer lemon, Rangpur lime and Sunki seeds can be stored for up to ten months. The polyembryony expression rate was slightly higher when measured in greenhouse than in B.O.D. chamber and remained stable in both environments until the seventh month, from which dropped sharply. Citrumelo Swingle seeds expressed the highest polyembryony rate (18.8%, followed by Rangpur lime and Volkamer lemon (average value of 13.7%, Sunki (9.4% and Trifoliate (3.2%. Despite some differences among varieties, the viability of rootstock stored seeds can be monitored either in the greenhouse or in B

Role of abscisic acid (aba) in modulating the responses of two apple rootstocks to drought stress

International Nuclear Information System (INIS)

Zhang, L.; Li, X.; Li, B.; Han, M.; Liu, F.; Zhang, L.; Zheng, P.

2014-01-01

Drought stress is considered as the main limiting factor for apple (Malus domestica L.) production in some semi-arid areas of China. In this study, we investigated the modulation role of abscisic acid (ABA) and fluridone (ABA synthesis inhibitor) on water relations and antioxidant enzyme system in 2-year-old seedlings of two apple rootstocks i.e. Malus sieversii (Ledeb.) Roem. (MS) and Malus hupehensis (Pamp.) Rehd. (MH). Drought stress induced ion leakage, accumulation of malondiadehyde (MDA) and decreases in leaf water potential and relative water content (RWC) in both rootstocks, which were significantly alleviated by exogenous ABA application. Drought stress also induced markedly increases in endogenous ABA content and activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR), and glutathione reductase (GR), to a greater magnitude in MS as compared to MH rootstock. Concentration of 100 mol/L and 50 mol/L ABA had the most positive effects on drought-stressed rootstocks of MS and MH, respectively. Spraying optimum exogenous ABA contributed to enhancement in most of the above antioxidant enzymes activities but reduction in content of MDA and maintained the appropriate leaf water potential and RWC in both rootstocks. Pretreatment with fluridone aggravated ion leakage and the accumulation of MDA in two apple rootstocks under drought stress, which was overcome by exogenous ABA application to some extent. In conclusion, the endogenous ABA was probably involved in the regulation of two apple rootstocks in responses to drought stress. (author)

Breeding rootstocks for Prunus species: Advances in genetic and genomics of peach and cherry as a model

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Verónica Guajardo

2015-08-01

Full Text Available Prunus rootstock is an important choice in optimizing productivity of grafted cultivars. Nevertheless, many Prunus rootstocks are notoriously intolerant to hypoxia which is caused by waterlogging and/or heavy soils. There is no available information to help select Prunus rootstocks that are tolerant to stress conditions such as root hypoxia caused by excess moisture. Information from genetic maps has demonstrated a high level of synteny among Prunus species, and this suggests that they all share a similar genomic structure. It should be possible to identify the genetic determinants involved in tolerance to hypoxia and other traits in Prunus rootstocks by applying methods to identify regions of the genome involved in the expression of important traits; these have been developed mainly in peach which is the model species for the genus. Molecular markers that are tightly linked to major genes would be useful in marker-assisted selection (MAS to optimize new rootstock selection. This article provides insight on the advances in the development of molecular markers, genetic maps, and gene identification in Prunus, mainly in peach; the aim is to provide a general approach for identifying the genetic determinants of hypoxia stress in rootstocks.

Preformation in vegetative buds of pistachio (Pistacia vera): relationship to shoot morphology, crown structure and rootstock vigor.

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Spann, Timothy M; Beede, Robert H; Dejong, Theodore M

2007-08-01

Effects of rootstock, shoot carbohydrate status, crop load and crown position on the number of preformed leaf primordia in the dormant terminal and lateral buds of mature and immature 'Kerman' pistachio (Pistacia vera L.) trees were investigated to determine if rootstock vigor is associated with greater shoot preformation. There was no significant variation in preformation related to the factors studied, suggesting strong genetic control of preformation in 'Kerman' pistachio. The growth differences observed among trees on different rootstocks were associated with greater stimulation of neoformed growth in trees on the more vigorous rootstocks. However, most annual extension growth in mature tree crowns was preformed, contrasting with the relatively high rate of neoformation found in young tree crowns. Large amounts of neoformed growth in young trees may allow the trees to become established quickly and secure resources, whereas predominantly preformed growth in mature trees may allow for continued crown expansion without outgrowing available resources. We hypothesized that the stimulation of neoformed growth by the more vigorous rootstocks is associated with greater resource uptake or transport, or both. Understanding the source of variation in shoot extension growth on different rootstocks has important implications for orchard management practices.

First report of root rot caused by Phytopythium helicoides on pistachio rootstock in California

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We examined pathogenicity of Phytopythium helicoides on UCB-1 rootstock to investigate its role in root disease and collapse observed on potted pistachio plants. Approximately 25 potted 2-year-old pistachio rootstock trees in a Kern County, CA, research plot maintained outdoors and irrigated to cont...

Fruit quality of seedless watermelon grafted onto squash rootstocks under different production systems.

Science.gov (United States)

Liu, Qianru; Zhao, Xin; Brecht, Jeffrey K; Sims, Charles A; Sanchez, Tatiana; Dufault, Nicholas S

2017-11-01

The market demand for seedless watermelon has been continuously increasing because of consumer preference. Grafting is a useful tool to manage soilborne diseases in watermelon production, but the use of squash rootstocks may negatively affect watermelon fruit quality. Currently, most research has focused on seeded cultivars, while grafting effects on seedless watermelons remain largely unknown. This multi-season study was conducted to assess the effects of squash rootstocks, including both Cucurbita maxima × C. moschata and C. moschata cultivars, with intact or excised and regenerated roots, on fruit quality of seedless watermelon 'Melody' using both instrumental and sensory measurements under different production scenarios. The grafted watermelon plants were also challenged by field inoculation with Fusarium oxysporum f.sp. niveum. A combination of instrumental measurements and consumer sensory analyses suggested that fruit quality of the seedless watermelon 'Melody' was not impacted by the use of the squash rootstocks used in this study, which included soluble solids content, titratable acidity, pH and most fruit sensory properties. Watermelon flesh firmness was increased by grafting but the grafting effect on lycopene content was inconclusive. Root excision and regeneration did not influence the grafting effect, whereas the grafting effect on flesh firmness varied among the rootstocks under Fusarium inoculation. Overall, grafting with squash rootstocks did not reduce fruit quality attributes of 'Melody' but improved texture. Our results support incorporating grafting into integrated management programs for seedless watermelon production. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Selection of Almond Vegetative Rootstocks for Water Stress Tolerance Based on the Morphological Markers

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A.A. Shokouhian

2016-02-01

Full Text Available Introduction: One of the microbiological preparations used for this study was Effective Microorganisms (EM, being a commercial mixture of photosynthesizing bacteria, Actinomycetes, lactic acid bacteria, yeasts and fermenting fungi. The microbiological composition of the EM concentrateincludesStreptomyces albus, Propioni bacterium freudenreichil, Streptococcus lactis, Aspergillus oryzae, Mucor hiemalis, Saccharomycescerevisiae and Candida utilis. Moreover, EM also contains an unspecified amount of Lactobacillus sp. Rhodo pseudomonas sp. and Streptomyces griseus. Effective Microorganisms have a positive effect on the decomposition of organic matter, limiting putrefaction, increasing nitrogen content in the root medium of plants, phosphorus, improving soil fertility and as a result contributing to the growth and development of the root systems of plants. Selection of almond vegetative rootstocks for water stress tolerance is important for almond crop production in arid and semi-arid regions. The study of the eco-morphological characteristics that determine the success of a rootstock in a particular environment is a powerful tool for both agricultural management and breeding purposes. The aim of this work was to select the new rootstocks for water shortage tolerance, impact of water stress as well as Effective Microorganism (EM on morphological characteristics of almond rootstocks. Materials and Methods: In order to select the new rootstocks for water shortage tolerance, impact of water stress as well as EMonmorphologicalcharacteristics of almondrootstocks were studiedin thedepartment ofHorticulture, Ferdowsi University of Mashhad, in 2011-2012. The experiment was carried out with four replications in a completely random blockdesign to study the effects of two concentrations of EM (0 and 1%, three irrigation levels (normal irrigation 100%-control-and irrigation after depletion of 33 and 66% of available water, and four almond rootstocks including GF

Evaluation of Freezing Damage in some Pistachio Seedling Rootstocks

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Maryam Afrousheh

2018-06-01

Full Text Available A greenhouse experiment was conducted to evaluate the freezing damage in some pistachio rootstocks by ion leakage and pH changes of leaked solution. A factorial experiment was carried out in randomized block designs (RBD with three factors: Temperature (A including 4 ̊C, 0 ̊C, -2 ̊C, -4 ̊C, -6 ̊C, Time (B including 3, 12, 24h , and Rootstock (C including P. vera cv 'Badami Zarand' (V13 and 'Sarakhs' (S5, P. mutica (M1and P. atlantica (A7. For this, one-year-old seedlings were kept at these five temperatures in incubator for 2 hours. Then in the first 24 hours in three hour intervals and during four days, EC and pH in leaked solution were measured daily. After four days the seedling samples were autoclaved at temperatures 105°C for 4 minutes to destroy all cell membrane. EC and pH of remaining solution were measured again and the percentage of ionic leakage was calculated. The results showed that the best time to evaluate the pH and ionic leakage was 24 hours after incubation of samples. Based on the results, ionic leakage dramatically increased with decreasing temperatures from 0°C to -6°C, while pH of leaked solution had no significant difference in 0°C and 4°C temperature treatments. When temperature reduced from 0°C to -6°C, like ionic leakage, pH greatly reduced. So the pH of the leaked solution could be an appropriate tool to study the freezing damage of pistachio rootstocks. Based on the results of pH and ionic leakage, P. mutica and P. atlantica were the most frost tolerant and sensitive rootstocks of this experiment, respectively.

Performance of ‘Okitsu’ satsuma mandarin trees on different rootstocks in Northwestern Parana State

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Zuleide Hissano Tazima

2014-10-01

Full Text Available In the State of Paraná, citrus production is based mainly on Rangpur lime rootstock, which has good results with the established cultivars. However, research is needed into rootstocks for use with cultivars that remain to be commercially exploited. The objective of this study was to evaluate the vegetative development and yield of ‘Okitsu’ satsuma mandarin plants (Citrus unshiu Marc., as well as fruit quality, budded on nine rootstocks in the Northwest State of Paraná, Brazil. The orchard was established at the Experimental Station of the Agronomic Institute of Paraná-IAPAR, Paranavaí, PR, in January 2001. The experimental design was randomized blocks with nine treatments, three replications, and two plants per plot. The rootstocks were Rangpur lime (Citrus limonia Osb., Cleopatra mandarin (Citrus reshni hort. ex Tanaka, C-13 citrange [Citrus sinensis × Poncirus trifoliata orange (L. Raf.], Volkamer lemon (Citrus volkameriana V. Ten. e Pasq., Carrizo citrange [C. sinensis × P. trifoliata (L. Raf.], Sunki mandarin (Citrus sunki hort. ex Tanaka, trifoliate orange [P. trifoliata (L. Raf. ], Swingle citrumelo [Citrus paradisi Macfad. cv. Duncan × P. trifoliata (L. Raf.], and Caipira DAC sweet orange [C. sinensis (L. Osb.]. The largest plant canopy to ‘Okitsu’ was induced by Cleopatra and the lowest by trifoliata, with 37.1 m3 and 9.9 m3, respectively. The highest relationship between scion and rootstock trunk diameter was observed for the plants budded on Swingle. The largest accumulated yields per plant over eight seasons were induced by Volkamer, Rangpur, Caipira DAC, Cleopatra, and Carrizo, ranging from 867.3 to 989.6 kg. These rootstocks also induced the largest fruit mass, along with Sunki, ranging from 173.3 to 188.0 g. Trifoliate induced accumulated production of 52.5% in relation to Rangpur lime. Rangpur, Carrizo, trifoliate, and Swingle induced the largest averages for the ratio, ranging from 10.41 to 10.79. For orchard

Rootstock and vineyard floor management influence on 'Cabernet Sauvignon' grape yeast assimilable nitrogen (YAN).

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Lee, Jungmin; Steenwerth, Kerri L

2011-08-01

This is a study on the influence that two rootstocks (110R, high vigour; 420A, low vigour) and three vineyard floor management regimes (tilled resident vegetation - usual practise in California, and barley cover crops that were either mowed or tilled) had upon grape nitrogen-containing compounds (mainly ammonia and free amino acids recalculated as YAN), sugars, and organic acids in 'Cabernet Sauvignon' clone 8. A significant difference was observed for some of the free amino acids between rootstocks. In both sample preparation methods (juiced or chemically extracted), 110R rootstock grapes were significantly higher in SER, GLN, THR, ARG, VAL, ILE, LEU, and YAN than were 420A rootstock grapes. Differences in individual free amino acid profiles and concentrations were observed between the two sample preparations, which indicate that care should be taken when comparing values from dissimilar methods. No significant differences among vineyard floor treatments were detected, which suggests that mowing offers vineyard managers a sustainable practise, alternative to tilling, without negatively affecting grape nitrogen compounds, sugars, or organic acids. Published by Elsevier Ltd.

Effect of rootstocks on fruit quality and aroma characteristics of watermelon (Citrullus lanatus

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Onur Karaağaç

2018-06-01

Full Text Available In recent years, grafted watermelon seedling use has been rapidly increasing due to providing tolerance to stress conditions and positively affecting on yield potential. Fruit quality was varied depending on the rootstock used positively or negatively in grafted vegetables. The number of research is limited in this topic. The effect of the rootstocks on fruit quality has not been fully revealed in grafted watermelon production. In this study, the using of the inbred lines (one Cucurbita moschata and four Cucurbita maxima and interspecific cross (five C. maxima × C. moschata rootstocks were investigated for fruit quality and aroma characteristics on the watermelon. Non-grafted Crisby F1 watermelon cultivar, one bottle gourd (Argentario F1 and two interspecific rootstock cultivars (Obez F1, Shintosa F1 were used as control commercial cultivars. In all grafted watermelon, the fruit flesh firmness was higher than non-grafted watermelon (10.73 N. According to the rootstock x scion combinations, the fruit firmness was varied between 13.75 N (K6/C and 22.53 N (M6/C. The rind thickness was changed between 16.05 (K9/C - 18.24 mm (Argentario/C. In the most of the grafted combinations, the rind thickness increased. Rootstocks did not effect on fruit shape. Higher total soluble solids were determined in all graft combinations than non-grafted watermelon. The highest soluble solids contents were determined in the combination of M6/C (12.87%, M3/C (12.53% and B1/C (12.50%. The vitamin C contents were significantly affected by rootstocks. These values in grafted watermelons increased by 30.30% (M3/C and 17.09% (Argentario/C reduction was observed compared to non-grafted watermelon. The lycopene content of eight combinations were found higher and four of them less than non-grafted watermelon. As a result of degustation panel tests, it was determined that M2/C (4.87, M3/C (4.53, B1/C (4.35 Argentario/C (29.4 and Obez/C (4.14 combinations scores were higher than

Discovery of viruses and virus-like pathogens in pistachio using high-throughput sequencing

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Pistachio (Pistacia vera L.) trees from the National Clonal Germplasm Repository (NCGR) and orchards in California were surveyed for viruses and virus-like agents by high-throughput sequencing (HTS). Analyses of 60 trees including clonal UCB-1 hybrid rootstock (P. atlantica × P. integerrima) identif...

Prunus hybrids rootstocks for flat peach

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Pilar Legua

2012-02-01

Full Text Available Peach (Prunus persica L. is the most important stone fruit tree grown in Spain and is the second most important fruit crop in Europe. The influence of eight Prunus rootstocks (GF-677, Krymsk® 86, PADAC 97-36, PADAC 99-05, PADAC 9912-03, PADAC 0024-01, PAC 0021-01 and PAC 0022-01 on vigor, yield and fruit quality traits of 'UFO 3' flat peach cultivar was studied. The highest trunk cross sectional area was exhibited by GF-677 and the lowest by PADAC 99-05, while intermediate values were found on the other rootstocks. The highest yield efficiency was found on PADAC 99-05, PAC 0021-01, PAC 0022-01 and PADAC 0024-01 and the lowest was shown on Krymsk® 86. The fruit quality parameters measured were color, fruit and stone weights, equatorial diameter, pulp thickness, pulp yield, firmness, pH, soluble solids content and titratable acidity. 'UFO 3' grafted on GF-677 resulted in the largest fruit weight, while the smallest was on PADAC 99-05. Fruits of 'UFO 3' showed a tendency to have higher firmness, higher red colored skin and RI when grafted on PADAC 99-05.

White dwarf-red dwarf binaries in the Galaxy

NARCIS (Netherlands)

Besselaar, E.J.M. van den

2007-01-01

This PhD thesis shows several studies on white dwarf - red dwarf binaries. White dwarfs are the end products of most stars and red dwarfs are normal hydrogen burning low-mass stars. White dwarf - red dwarf binaries are both blue (white dwarf) and red (red dwarf). Together with the fact that they are

Apple replant disease and the –omics: interaction of apple rootstock metabolome and the soil microbiome

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Apple replant disease (ARD) negatively impacts tree health and reduces crop yield in new orchard plantings. Use of tolerant rootstock cultivars can diminish the growth limiting effects of ARD; however specific rootstock attributes enabling ARD tolerance are not understood. Systems biology tools were...

INFLUENCE OF ROOTSTOCKS ON Fusarium WILT, NEMATODE INFESTATION, YIELD AND FRUIT QUALITY IN WATERMELON PRODUCTION

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Juan Carlos Álvarez-Hernández

2015-08-01

Full Text Available Cucurbita maxima x Cucurbita moschata rootstock are used to prevent infection with Fusarium oxysporum f. sp. niveum in watermelon production; however, this rootstock is not effective against nematode attack. Because of their vigor, the grafted plants can be planted at lower plant densities than the non-grafted plants. The tolerance to Fusarium oxysporum f. sp. niveum and Meloidogyne incognita was assessed in watermelon plants grafted onto a hybrid of Citrullus lanatus cv Robusta or the Cucurbita maxima x Cucurbita moschata cv Super Shintoza rootstocks. The densities of plants were 2083 and 4166 plants ha-1. Non-grafted watermelons were the controls. The Crunchy Red and Sangría watermelon cultivars were used as the scions, it the latter as a pollinator. The experiments were performed for two production cycles in soils infested with Fusarium oxysporum f. sp. niveum and Meloidogyne incognita. The incidence of Fusarium oxysporum f. sp. niveum was significantly greater in the non-grafted than in the grafted plants. The grafted plants presented similar resistance to Fusarium regardless of the rootstock. The root-knot galling index for Meloidogyne incognita was significantly lower in plants grafted onto Citrullus lanatus cv Robusta than onto the other rootstock. The yields of plants grafted onto Citrullus lanatus cv Robusta grown at both plant densities were significantly higher than in the other treatments.

Formation of ‘Crioula’ guava rootstock under saline water irrigation and nitrogen doses

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Leandro de P. Souza

Full Text Available ABSTRACT The objective of this research was to evaluate the growth and formation of fresh and dry weight of ‘Crioula’ guava rootstock irrigated with waters of different saline levels and nitrogen (N doses, in an experiment conducted in plastic tubes under greenhouse conditions. The experimental design was randomized blocks, in a 5 x 4 factorial scheme with four replicates, and the treatments consisted of five levels of water electrical conductivity - ECw (0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1 and four N doses (70, 100, 130 and 160% of the N dose recommended for the cultivation of guava seedlings, cv. ‘Paluma’. The dose referring to 100% corresponds to 773 mg of N dm-3. The highest growth of ‘Crioula’ guava rootstock was obtained with ECw of 0.3 dS m-1 and fertilization of 541.1 mg N dm-3 of soil; increasing N doses did not reduce the deleterious effect of the salt stress on the growth and phytomass formation of ‘Crioula’ guava rootstock; irrigation with water of up to 1.75 dS m-1, in the production of guava rootstocks, promotes acceptable reduction of 10% in growth and quality of the seedlings.

Bemisia tabaci MED Population Density as Affected by Rootstock-Modified Leaf Anatomy and Amino Acid Profiles in Hydroponically Grown Tomato

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Katja Žanić

2018-02-01

Full Text Available Bemisia tabaci is one of the most devastating pests in tomato greenhouse production. Insecticide resistance management for B. tabaci requires a novel approach that maximizes non-chemical methods for pest control. The aim of this study was to test the effects of rootstocks on B. tabaci populations in hydroponically grown tomato plants. In order to contribute to the better understanding of the mechanisms defining the attractiveness of plant to the aerial pest, the effects of rootstocks on leaf anatomy and the amino acid composition of phloem sap were assessed. A two-factorial experimental design was adopted using cultivars (rootstock cultivars and Clarabella grown as either non-grafted or grafted with cultivar Clarabella as a scion. The rootstock cultivars included Arnold, Buffon, Emperador, and Maxifort. A reduction in B. tabaci density was observed using all rootstock cultivars. The number of adult individuals per leaf was 2.7–5.4 times lower on rootstock cultivars than on Clarabella. The number of large nymphs per square centimeter was at least 24% higher on non–grafted Clarabella compared with all other treatments. The leaf lamina thickness and mesophyll thickness were lower in self-grafted Clarabella than in non-grafted or in one grafted on rootstock cultivars; however, the extent of this reduction depended on the rootstock. The leaves with thinner laminae were generally less attractive to B. tabaci. Eighteen amino acids were detected in the exudates of phloem sap. In all treatments, the most abundant amino acid was γ-aminobutyric acid (GABA, followed by proline, serine, alanine, and histidine. The scion cultivar Clarabella was the most attractive to B. tabaci and had a higher content of leucine than did rootstock cultivars, and a higher content of lysine compared to Buffon and Maxifort. The features modified by rootstock such are changes in leaf anatomy can affect the attractiveness of plants to B. tabaci. Thus, the grafting of tomato

Crop-Specific Grafting Methods, Rootstocks and Scheduling-Tomato

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Grafting has gained popularity as a method to manage plant diseases previously controlled by soil fumigation with methyl bromide. Some of the most significant soilborne pest problems for which resistant rootstocks may be beneficial include root-knot nematodes, Verticillium wilt, and southern blight....

Comparative response of six grapevine rootstocks to inoculation with arbuscular mycorrhizal fungi based on root traits

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Pogiatzis, Antreas; Bowen, Pat; Hart, Miranda; Holland, Taylor; Klironomos, John

2017-04-01

Arbuscular mycorrhizal (AM) symbiosis has been proven to be essential in grapevines, sustaining plant growth especially under abiotic and biotic stressors. The mycorrhizal growth response of young grapevines varies among rootstock cultivars and the underlying mechanisms involved in this variation are unknown. We predicted that this variation in mycorrhizal response may be explained by differences in root traits among rootstocks. We analyzed the entire root system of six greenhouse-grown rootstocks (Salt Creek, 3309 Couderc, Riparia Gloire, 101-14 Millardet et de Grasset, Swarzmann, Teleki 5C), with and without AM fungal inoculation (Rhizophagus irregularis) and characterized their morphological and architectural responses. Twenty weeks after the inoculation, aboveground growth was enhanced by AM colonization. The rootstock varieties were distinctly different in their response to AM fungi, with Salt Creek receiving the highest growth benefit, while Schwarzmann and 5C Teleki receiving the lowest. Plant responsiveness to AM fungi was negatively correlated with branching intensity (fine roots per root length). Furthermore, there was evidence that mycorrhizas can influence the expression of root traits, inducing a higher branching intensity and a lower root to shoot ratio. The results of this study will help to elucidate how interactions between grapevine rootstocks and AM fungi may benefit the establishment of new vineyards.

Grapevine rootstock effects on scion sap phenolic levels, resistance to Xylella fastidiosa infection, and progression of Pierce’s disease

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Christopher Michael Wallis

2013-12-01

Full Text Available The xylem-limited bacterium Xylella fastidiosa (Xf causes Pierce’s disease (PD, an important disease of grapevine, Vitis vinifera L.. Grapevine rootstocks were developed to provide increased resistance to root disease, but rootstock effects on cane and vine diseases remain unclear. Grapevines that consisted of Cabernet Sauvignon or Chardonnay grafted to 13 different rootstocks were inoculated with Xf and evaluated for PD severity and Xf titer after six months. A subset of six rootstock/scion combinations had xylem sap phenolic levels assessed in non-infected and Xf-infected grapevines. Vigor also was analyzed by measuring root lengths and masses. Cabernet Sauvignon grafted to 101-14MG, 1103P, 420A, or Schwarzmann had reduced PD severity compared to Cabernet Sauvignon grafted to 110R, 5BB, or SO4. Chardonnay grafted to Salt Creek or Freedom had reduced PD severity compared to Chardonnay grafted to RS3 or Schwarzmann. Chardonnay grafted to RS3 had greater Xf titer than Chardonnay grafted to 101-14MG, Freedom, or Salt Creek. No other differences in Xf titer among rootstocks were observed. Of the six scion/rootstock combinations which had xylem sap phenolics analyzed, Chardonnay/ RS3 had the highest levels of most phenolics whereas Cabernet Sauvignon/101-14MG had the lowest phenolic levels. However, Chardonnay/101-14MG, which had mild PD symptoms, had greater sap levels of caftaric acid than other scion/rootstock combinations. Sap levels of caftaric acid, methyl salicylate, a procyanidin trimer, and quinic acid were greater in Xf-infected versus non-infected grapevines. Chardonnay on 101-14MG or Salt Creek had greater root mass than Chardonnay on RS3. Cabernet Sauvignon on 101-14MG had greater root mass than Cabernet Sauvignon on 110R. These results identified rootstocks with the capacity for reducing PD symptom progression. Rootstocks also were shown to affect Xf titer, xylem sap phenolic levels, and plant vigor.

Cabernet Sauvignon grapevine grafted onto rootstocks during the autumn-winter season in southeastern Brazilian

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Claudia Rita de Souza

2015-02-01

Full Text Available The change of grape (Vitis vinifera harvest from summer to winter through double pruning management has improved the fine wine quality in southern Brazil. High altitude, late cultivar and grafting combination all need to be investigated to optimize this new viticulture management. For this purpose, this study was carried out during the 2011 and 2012 growing seasons in a high altitude region of the state of Minas Gerais, Brazil, using eight grafting combinations for five year old Cabernet Sauvignon vines. The stem water potential, photosynthetic rate and stomatal conductance were not affected by rootstock type. The rootstocks IAC 766 and 101-14 induced, respectively, the highest and lowest vegetative vigor in Cabernet Sauvignon, as shown by leaf area and pruning weight. In the 2011 growing season, the leaf chlorophyll contents were increased in IAC 766, whereas vines grafted onto 101-14 accumulated more leaf starch, probably due to reduced vegetative and reproductive growth. In general, rootstocks K5BB, 1045P, SO4 and IAC 766 had the highest yield as compared to 1103P and 101-14. Berries from the grapevine with the highest yield did not differ in pH, total soluble solids and acidity. The rootstocks did not influence the anthocyanins and total phenols in both growing seasons. Quality parameters were better in the 2011 than in the 2012 growing season due to better climatic conditions, mainly less rainfall. The best performance of Cabernet Sauvignon was achieved when grafted onto K5BB, 1045P, SO4 and IAC 766 rootstocks.

Performance of Minneola tangelo trees grafted over six rootstocks in Colombia Tropical Lowland (1997-2010

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Hans Chaparro

2017-07-01

Full Text Available ‘Cleopatra’ tangerine (Citrus reshni hort. ex Tanaka is a commonly used rootstock in the piedmont of Meta department, Colombia for establishing of commercial citrus orchards. Have allowed a late production entrance rootstock and produced big plants when grafted with tangelo ‘Minneola’ (C. reticulata Blanco x C. paradise Macf, decreasing the productive efficiency in plants and hard crop practices. The evaluated performance were as follows:  tree size, productive efficiency and fruit quality of tangelo ‘Minneola’ grafted in six rootstocks. It found that the cumulated production of 11 years was better with Citrumelo ‘Swingle’ (Citrus paradisi Macf. × Poncirus trifoliata (L. Raf with 1388.3 kg tree-1, followed by ‘Cleopatra’ (Citrus reshni hort. ex Tanaka with 893.2 kg.tree-1, in last place was ‘Carrizo’ (Citrus sinensis Osb. × Poncirustrifoliata (L. Raf with 182.9 kg tree-1. The other rootstocks, had a medium production. The greatest height and canopy value, was found with ‘Cleopatra’ without significant differences with Citrumelo ‘Swingle’. In fruit quality no significant differences occurred.

Agronomical Parameters, Sugar Profile and Antioxidant Compounds of “Catherine” Peach Cultivar Influenced by Different Plum Rootstocks

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Carolina Font i Forcada

2014-02-01

Full Text Available The influence of seven plum rootstocks (Adesoto, Monpol, Montizo, Puebla de Soto 67 AD, PM 105 AD, St. Julien GF 655/2 and Constantí 1 on individual and total sugars, as well as on antioxidant content in fruit flesh of “Catherine” peaches, was evaluated for three years. Agronomical and basic fruit quality parameters were also determined. At twelve years after budding, significant differences were found between rootstocks for the different agronomic and fruit quality traits evaluated. The Pollizo plum rootstocks Adesoto and PM 105 AD seem to induce higher sweetness to peach fruits, based on soluble solids content, individual (sucrose, fructose and sorbitol and total sugars. A clear tendency was also observed with the rootstock Adesoto, inducing the highest content of phenolics, flavonoids, vitamin C and relative antioxidant capacity (RAC. Thus, the results of this study demonstrate the significant effect of rootstock on the sugar profile and phytochemical characteristics of peach fruits. In addition, this work shows the importance of the sugar profile, because specific sugars play an important role in peach flavour quality, as well as the studied phytochemical compounds when looking for high quality peaches with enhanced health properties.

Grafting of watermelon (Citrullus lanatus cv. Mahbubi) onto different squash rootstocks as a means to minimize cadmium toxicity.

Science.gov (United States)

Shirani Bidabadi, Siamak; Abolghasemi, Reza; Zheng, Si-Jun

2018-06-07

To test the possibility that using appropriate rootstocks could improve the tolerance of watermelon to cadmium (Cd) toxicity, a greenhouse experiment was conducted to determine growth and antioxidant activities of watermelons, either nongrafted or grafted onto summer squash and winter squash. We provided nutrient solutions having four levels (0, 50, 100, and 200 μM) of cadmium to treat the plants. Shoot and root biomass reduction were significantly lower in summer squash rootstock-grafted watermelon than winter squash rootstock-grafted and nongrafted watermelons. Cadmium induced a smaller decrease in leaf area index in grafted watermelons compared with nongrafted plants. The Cd- related reductions in chlorophyll content and efficiency of photosynthesis were more severe in nongrafted watermelons compared with dose grafted onto summer squash. Cd accumulation in shoot at the highest dose (200 µM) of CdCl 2 was significantly lower (19.76 mg/kg) in summer squash rootstock-grafted watermelon compared with winter squash rootstock-grafted (37.58 mg/kg) and nongrafted watermelon (72.12 mg/kg). H 2 O 2 , MDA production and electrolyte leakage of summer squash rootstock-grafted watermelon showed less increase, which was associated with a significant increase in the activities of antioxidant. The improved crop performance of grafted watermelons was attributed to their strong capacity to inhibit Cd accumulation in the aerial parts.

Root Proteomic Analysis of Grapevine Rootstocks Inoculated with Rhizophagus irregularis and Fusarium oxysporum f. sp. herbemontis

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Elisa Vilvert

Full Text Available ABSTRACT Grapevine decline and death caused by the pathogenic fungus Fusarium oxysporum f. sp. herbemontis is among the main phytosanitary problem for viticulture in southern Brazil. The eradication of infected plants is presently the most common procedure for disease control in vineyards. Inoculation with arbuscular mycorrhizal fungi is an option to reduce or neutralize the negative impacts of soil pathogenic microorganisms, but the mechanisms of plant response involved in this process are not yet completely elucidated. In order to better understand these mechanisms, an experiment was carried out to identify proteins related to plant defence induced by the mycorrhizal fungus after infection with the pathogenic fungus. We used the grapevine rootstocks SO4 and R110 (susceptible and resistant to the pathogenic fungus, respectively inoculated or not inoculated with the mycorrhizal fungus Rhizophagus irregularis, and inoculated or not inoculated with Fusarium oxysporum f. sp. herbemontis. Growth of the rootstocks’ shoot and root and presence of pathogenic symptoms were evaluated. The protein profiles of roots were characterized by two-dimensional electrophoresis and proteins were identified using mass spectrometry. The grapevine rootstocks inoculated with R. irregularis had higher biomass production and lower level of pathogenic symptoms. The R110 rootstock differentially accumulated 73 proteins, while SO4 accumulated 59 proteins. Nine plant-defence proteins were expressed by SO4 rootstock, and six were expressed by R110 rootstock plants. The results confirm the effect of mycorrhizal fungi in plant growth promotion and their potential for biological control against soil pathogenic fungus. Protein expression is dependent on rootstock characteristics and on the combination of plant material with the fungi.

Obtaining cherry and apple tree radiomutants by irradiation of grafts in gamma cell

International Nuclear Information System (INIS)

Chvojka, L.; Fridrich, A.

1980-01-01

The aim of the study was to obtain dwarf mutants of cherry and apple trees. Two methods of irradiation were used: a) winter grafts were irradiated with 60 Co (4-5 kR) and grafted in the crowns of adult trees or of two-year-old rootstocks; b) summer buds on mature annual shots were irradiated with 2-3 kR and grafted on two-year-old rootstocks. Thus the clones of dwarf cherry trees (cv. Napoleon's and Techlovicka) were obtained which were further tested for fruit-bearing in experimental plantations. Colour mutants of apple tree (cv. Champion) with yellow and red fruits were also obtained as well as dwarf types of trees. (author)

Chemical characteristics of grape juices from different cultivar and rootstock combinations

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Rita de Cássia Mirela Resende Nassur

2014-07-01

Full Text Available The objective of this work was to evaluate the influence of different combinations of grape cultivars and rootstocks on chemical characteristics of grape juices. Six treatments were evaluated, consisting of combinations between the Isabel Precoce and BRS Cora grape cultivars and the 'IAC 766', 'IAC 313', and 'IAC 572' rootstocks. Approximately 10 L of juice were obtained per treatment. Analyses of color, total soluble solids content, pH, anthocyanins, total phenolics, total sugars, and quantification and identification of biogenic amines by HPLC were performed. Biogenic amines, such as putrescine, cadaverine, spermidine, and spermine, were found in all evaluated cultivars. By principal component analysis (PCA, treatments can be divided into two groups, according to the cultivar. Juices obtained from 'Isabel Precoce' are characterized by higher levels of total sugar content and soluble solids; however, juices from 'BRS Cora' are positively correlated with phenolic content, anthocyanins, and color and acidity parameters. The differences found by PCA for juices from the Isabel Precoce and BRS Cora cultivars indicate that, regardless of the rootstock used, the most important factor in the chemical characterization of juices is the grape cultivar.

Rooting and acclimatization of micropropagated marubakaido apple rootstock using Adesmia latifolia rhizobia.

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Muniz, Aleksander Westphal; de Sá, Enilson Luiz; Dalagnol, Gilberto Luíz; Filho, João Américo

2013-01-01

In vitro rooting and the acclimatization of micropropagated rootstocks of apple trees is essential for plant development in the field. The aim of this work was to assess the use of rhizobia of Adesmia latifolia to promote rooting and acclimatization in micropropagated Marubakaido apple rootstock. An experiment involving in vitro rooting and acclimatization was performed with four strains of rhizobium and two controls, one with and the other without the addition of synthetic indoleacetic acid. The inoculated treatments involved the use of sterile inoculum and inoculum containing live rhizobia. The most significant effects on the rooting rate, primary-root length, number of roots, root length, fresh-shoot biomass, and fresh-root biomass were obtained by inoculation with strain EEL16010B and with synthetic indole acetic acid. However, there was no difference in the growth of apple explants in the acclimatization experiments. Strain EEL16010B can be used to induce in vitro rooting of the Marubakaido rootstock and can replace the use of synthetic indoleacetic acid in the rooting of this cultivar.

ROOTSTOCKS EFFECTS ON THE PHYSICOCHEMICAL CHARACTERISTICS OF BORDÔ, ISABEL AND IAC 138-22 MÁXIMO MUST AND WINE

OpenAIRE

MARLON JOCIMAR RODRIGUES DA SILVA; LUCIANA TREVISAN BRUNELLI; MARA FERNANDES MOURA; JOSÉ LUIZ HERNANDES; SARITA LEONEL; MARCO ANTONIO TECCHIO

2017-01-01

ABSTRACT It has been demonstrated that rootstocks can influence grape characteristics, but there are few data in literature about the rootstocks influence in the wine characteristics, especially in wines elaborated with Vitis labrusca or hybrid grapes. This study evaluated the influence of ‘IAC 766’ and ‘106-8 Mgt’ rootstocks on the physicochemical characteristics of ‘Bordô’, ‘Isabel’ and ‘IAC 138-22 ‘Máximo’ musts and wines. The musts were evaluated for pH, soluble solids, total acidity and...

COMPATIBILITY AND FEASIBILITY OF GRAFT TOMATO CULTIVAR SANTA CRUZ KADA IN DIFFERENT ROOTSTOCKS

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A. R. Zeist

2015-02-01

Full Text Available Tomato production through the technique of grafting aims to control soil pathogens, induce flowering, and improve tolerance to waterlogging, salinity and alkalinity of the soil. For this work were performed 50 grafts for each type of rootstock, totaling 100 slips and 50 seedlings kept as control. After 15 days of grafting, the seedlings were evaluated on the percentage of picks grafting. The treatment which used the tomato cultivar Cherry Red® as rootstock presented results of vegetative growth (height and volume Cup higher than other treatments. However after transplanting, defective development was observed for plants with grafting when compared to the controls. After 35 days of follow up, there was a low survival rate, being 5% of the plants. According to the results obtained in this work the tomato cultivar Santa Cruz Kada® has good compatibility with the rootstock cultivar Cayenne® pepper and tomato cultivar Cherry Red®

Rootstock-to-scion transfer of transgene-derived small interfering RNAs and their effect on virus resistance in nontransgenic sweet cherry.

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Zhao, Dongyan; Song, Guo-qing

2014-12-01

Small interfering RNAs (siRNAs) are silencing signals in plants. Virus-resistant transgenic rootstocks developed through siRNA-mediated gene silencing may enhance virus resistance of nontransgenic scions via siRNAs transported from the transgenic rootstocks. However, convincing evidence of rootstock-to-scion movement of siRNAs of exogenous genes in woody plants is still lacking. To determine whether exogenous siRNAs can be transferred, nontransgenic sweet cherry (scions) was grafted on transgenic cherry rootstocks (TRs), which was transformed with an RNA interference (RNAi) vector expressing short hairpin RNAs of the genomic RNA3 of Prunus necrotic ringspot virus (PNRSV-hpRNA). Small RNA sequencing was conducted using bud tissues of TRs and those of grafted (rootstock/scion) trees, locating at about 1.2 m above the graft unions. Comparison of the siRNA profiles revealed that the PNRSV-hpRNA was efficient in producing siRNAs and eliminating PNRSV in the TRs. Furthermore, our study confirmed, for the first time, the long-distance (1.2 m) transfer of PNRSV-hpRNA-derived siRNAs from the transgenic rootstock to the nontransgenic scion in woody plants. Inoculation of nontransgenic scions with PNRSV revealed that the transferred siRNAs enhanced PNRSV resistance of the scions grafted on the TRs. Collectively, these findings provide the foundation for 'using transgenic rootstocks to produce products of nontransgenic scions in fruit trees'. © 2014 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

ROOTSTOCKS EFFECTS ON THE PHYSICOCHEMICAL CHARACTERISTICS OF BORDÔ, ISABEL AND IAC 138-22 MÁXIMO MUST AND WINE

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MARLON JOCIMAR RODRIGUES DA SILVA

2017-09-01

Full Text Available ABSTRACT It has been demonstrated that rootstocks can influence grape characteristics, but there are few data in literature about the rootstocks influence in the wine characteristics, especially in wines elaborated with Vitis labrusca or hybrid grapes. This study evaluated the influence of ‘IAC 766’ and ‘106-8 Mgt’ rootstocks on the physicochemical characteristics of ‘Bordô’, ‘Isabel’ and ‘IAC 138-22 ‘Máximo’ musts and wines. The musts were evaluated for pH, soluble solids, total acidity and soluble solids/acidity ratio. The wines were evaluated for density, alcohol content; total, volatile and fixed acidity; pH, dry extract, reducing sugars, reduced dry extract, alcohol in weight/reduced dry extract; free and total sulfur dioxide; anthocyanins, polyphenols index (I 280; polyphenols and total flavonoids and antioxidant activity. The ‘Bordô’, ‘Isabel’ and IAC 138-22 ‘Máximo’ musts had low soluble solids for winemaking. The ‘106-8 Mgt’ rootstock promoted higher dry extract content and reduced dry extract in Bordô wine, and lower total and fixed acidity in IAC 138-22 Máximo wine. In Isabel wine, higher pH was promoted by the ‘IAC 766’ rootstock. Aside from low total acidity of the Bordô wine, all the physicochemical characteristics of the wines studied are in accordance with Brazilian law. There was no effect of rootstocks in the phenolics content and antioxidant activity of wines.

Sistema radicular de porta-enxertos micropropagados de macieira colonizados com fungos micorrízicos arbusculares Root architecture of apple rootstocks inoculated with arbuscular mycorrhizal fungi

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Lucir Maria Locatelli

2002-09-01

Full Text Available A arquitetura do sistema radicular tem implicações na capacidade da planta de obter nutrientes e água do solo; aspecto, este, não muito considerado nos estudos de desenvolvimento vegetal. O objetivo deste trabalho foi avaliar o comportamento do sistema radicular de dois porta-enxertos micropropagados de macieira (Malus spp., em razão da associação micorrízica. Foram utilizados um porta-enxerto vigoroso e com grande capacidade de enraizamento (Marubakaido e outro ananicante e com sistema radicular pouco desenvolvido (M.9. As plantas oriundas de micropropagação foram transferidas para substrato à base de solo, a fim de serem enraizadas ex vitro. Antes ou após o enraizamento, inoculou-se uma mistura de três isolados de fungos micorrízicos arbusculares ou um filtrado com a biota não-micorrízica do inoculante. Aos 51 e 81 dias, avaliaram-se o número e o comprimento de eixos radiculares e das raízes de ordem 1, 2, 3 e 4. A inoculação micorrízica antes do enraizamento aumentou o número e o comprimento de raízes do porta-enxerto Marubakaido, porém, o portaenxerto M.9 teve o número e o comprimento de raízes diminuído quando a inoculação micorrízica ocorreu antes da fase de enraizamento.Root architecture is scarcely considered in plant physiology studies, despite its great importance to plant growth and development. In order to evaluate the behavior of the root systems of two varieties of apple (Malus spp. rootstock when subjected to mycorrhizal association. Two apple rootstocks were tested: Marubakaido, which is vigorous and roots easily, and M.9, which is dwarfing and poorly rooted. The micropropagated plantlets were transferred to a soil-based substrate and received AMF inoculum, or its non-mycorrhizal biota, before and after a 21-day rooting and weaning period. After 51 and 81 days, the number and length of root axes and of first-, second-, third- and fourth- order roots were evaluated. AMF inoculation before weaning and

Production of interstocked 'Pera' sweet orange nursey trees on 'Volkamer' lemon and 'Swingle' citrumelo rootstocks

OpenAIRE

Girardi,Eduardo Augusto; Mourão Filho,Francisco de Assis Alves

2006-01-01

Incompatibility among certain citrus scion and rootstock cultivars can be avoided through interstocking. 'Pera' sweet orange (Citrus sinensis L. Osbeck) nursery tree production was evaluated on 'Swingle' citrumelo (Poncirus trifoliata (L.) Raf x Citrus paradisi Macf) and 'Volkamer' lemon (Citrus volkameriana Pasquale) incompatible rootstocks, using 'Valencia' and 'Hamlin' sweet oranges (Citrus sinensis L. Osbeck), 'Sunki' mandarin (Citrus sunki Hort. ex Tanaka), and 'Cleopatra' mandarin (Citr...

The Effect of Different Cucurbit Rootstocks on Some Morphological and Physiological Traits of Cucumber (Cucumis sativus cv. Super Dominus

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reihane Mesgari

2017-02-01

Full Text Available Introduction: Cucumber is one of the most important vegetable crops for the local consumption and exportation. The use of grafted vegetable seedlings has been popular in many countries during recent years. Growing fruit-bearing vegetables, chiefly tomato, cucumber and watermelon through grafted seedlings become a widespread practice worldwide. Grafting is a valuable technique to avoid soil-borne diseases, provide biotic and abiotic stress tolerance, enhance nutrient uptake, optimize water use, and increase fruit yield and quality. Vegetable grafting is a new topic in Iran and there are a limited number of studies on grafted vegetable production. However, attention to grafting by researchers has recently increased. Suitable rootstocks should be identified and characterized for the effective utilization of grafting. The rootstock's vigorous root system increases the efficiency of water and nutrient absorption, and may also serve as a source of endogenous plant hormones, thus leading to increased growth and yield in addition to disease control. In the present study, we investigated the response of two Cucurbita sp. and an Iranian melon as rootstocks for cucumber. Materials and methods: In order to study the effect of cucurbit rootstocks and grafting method on growth, yield and fruit quality of cucumber (Cucumis sativus cv. Super Dominus, an experiment was conducted as a factorial design in the base of RCBD with three replications in the greenhouse and research farm, University of Zanjan. Treatments were included three rootstocks (Cucurbita moschata L., Lagenaria siceraria and Cucumis melo L. and ungrafted plants (control and two grafting method (hole insertion and splice grafting. Seeds were sown simultaneously in plastic pots. For obtaining the same stem diameter of scion and rootstocks, cucumber seeds were planted four days earlier than rootstocks seeds. The seedlings were grown in an environment-controlled greenhouse with 25/20 day

Root distribution of rootstocks for 'Tahiti' lime

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Neves Carmen Silvia Vieira Janeiro

2004-01-01

Full Text Available Field studies on citrus roots are important for genetic selection of cultivars and for management practices such as localized irrigation and fertilization. To characterize root systems of six rootstocks, taking into consideration chemical and physical characteristics of a clayey Typic Hapludox of the Northern State of Paraná, this study was performed having as scion the 'IAC-5 Tahiti' lime [Citrus latifolia (Yu. Tanaka]. The rootstocks 'Rangpur' lime (C. limonia Osbeck, 'Africa Rough' lemon (C. jambhiri Lush., 'Sunki' mandarin [C. sunki (Hayata hort. ex Tan.], Poncirus trifoliata (L. Raf., 'C13' citrange [C. sinensis (L. Osb. x P. trifoliata (L. Raf] and 'Catânia 2' Volkamer lemon (C. volkameriana Ten. & Pasq. were used applying the trench profile method and the SIARCS® 3.0 software to determine root distribution. 'C-13' citrange had the largest root system. 'Volkamer' lemon and 'Africa Rough' lemon presented the smallest amount of roots. The effective depth for 80 % of roots was 31-53 cm in rows and 67-68 cm in inter-rows. The effective distance of 80 % of roots measured from the tree trunk exceeded the tree canopy for P. trifoliata, 'Sunki' mandarin, and 'Volkamer' and 'Africa Rough' lemons.

EVALUATION OF GAS EXCHANGES IN DIFFERENT Prunus SPP. ROOTSTOCKS UNDER DROUGHT AND FLOODING STRESS

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ELSA KUHN KLUMB

2017-10-01

Full Text Available ABSTRACT The state of Rio Grande do Sul is the largest peach productor in Brazil; however, it still possesses poor yield values when compared with other states. One of the problems associated with this is the occurrence of soils with drainage problems, mainly in Pelotas region, which depending on the year period, may undergo water deficit or flooding situations in the great majority of the years, which harm the crop development and yield. Among the harmful effects caused by these stresses stand out, the decrease in the net assimilation rate, closure of stomata, reduction of the cell activities, production of reactive oxygen species, membrane and protein destabilization. Thus, the aim of this study was to investigate in what magnitude of the gaseous exchange parameters of Prunus spp. rootstocks are influenced under drought and flood stress. In the experiment, gas exchange parameters net photosynthetic rate (A stomata conductance (gs, intercellular carbon (Ci and transpiration (E] were evaluated in three Prunus spp. rootstocks (peach tree ‘Capdeboscq’ and plum trees ‘Julior’ and ‘Marianna 2624’ under three water conditions (control, water deficit and soil flooding for seven days. The three rootstocks proved more susceptible to flooding than to water deficit, only varying in response time, which is intrinsic to each genotype, and that there is a genetic variability for the tolerance to the studied stresses. The variation on physiological response to the water deficit stress was later in both evaluated genotypes. However, in general, ‘Julior’ presented greater tolerance to both stresses when compared to the other rootstocks evaluated. Such information is useful to help in the choice of rootstocks for plant production, in the orchard management and for plant breeding programs, aiming at the selection of new genotypes with increased tolerance to these water stresses.

Evaluating Clonal Expansion of HIV-Infected Cells: Optimization of PCR Strategies to Predict Clonality

Science.gov (United States)

Laskey, Sarah B.; Pohlmeyer, Christopher W.; Bruner, Katherine M.; Siliciano, Robert F.

2016-01-01

In HIV-infected individuals receiving suppressive antiretroviral therapy, the virus persists indefinitely in a reservoir of latently infected cells. The proliferation of these cells may contribute to the stability of the reservoir and thus to the lifelong persistence of HIV-1 in infected individuals. Because the HIV-1 replication process is highly error-prone, the detection of identical viral genomes in distinct host cells provides evidence for the clonal expansion of infected cells. We evaluated alignments of unique, near-full-length HIV-1 sequences to determine the relationship between clonality in a short region and clonality in the full genome. Although it is common to amplify and sequence short, subgenomic regions of the viral genome for phylogenetic analysis, we show that sequence identity of these amplicons does not guarantee clonality across the full viral genome. We show that although longer amplicons capture more diversity, no subgenomic region can recapitulate the diversity of full viral genomes. Consequently, some identical subgenomic amplicons should be expected even from the analysis of completely unique viral genomes, and the presence of identical amplicons alone is not proof of clonally expanded HIV-1. We present a method for evaluating evidence of clonal expansion in the context of these findings. PMID:27494508

Evaluating Clonal Expansion of HIV-Infected Cells: Optimization of PCR Strategies to Predict Clonality.

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Sarah B Laskey

2016-08-01

Full Text Available In HIV-infected individuals receiving suppressive antiretroviral therapy, the virus persists indefinitely in a reservoir of latently infected cells. The proliferation of these cells may contribute to the stability of the reservoir and thus to the lifelong persistence of HIV-1 in infected individuals. Because the HIV-1 replication process is highly error-prone, the detection of identical viral genomes in distinct host cells provides evidence for the clonal expansion of infected cells. We evaluated alignments of unique, near-full-length HIV-1 sequences to determine the relationship between clonality in a short region and clonality in the full genome. Although it is common to amplify and sequence short, subgenomic regions of the viral genome for phylogenetic analysis, we show that sequence identity of these amplicons does not guarantee clonality across the full viral genome. We show that although longer amplicons capture more diversity, no subgenomic region can recapitulate the diversity of full viral genomes. Consequently, some identical subgenomic amplicons should be expected even from the analysis of completely unique viral genomes, and the presence of identical amplicons alone is not proof of clonally expanded HIV-1. We present a method for evaluating evidence of clonal expansion in the context of these findings.

Clonality analysis of lymphoid proliferations using the BIOMED-2 clonality assays: a single institution experience

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Kokovic, Ira; Novakovic, Barbara Jezersek; Cerkovnik, Petra; Novakovic, Srdjan

2014-01-01

Background Clonality determination in patients with lymphoproliferative disorders can improve the final diagnosis. The aim of our study was to evaluate the applicative value of standardized BIOMED-2 gene clonality assay protocols for the analysis of clonality of lymphocytes in a group of different lymphoid proliferations. Materials and methods. With this purpose, 121 specimens from 91 patients with suspected lymphoproliferations submitted for routine diagnostics from January to December 2011 were retrospectively analyzed. According to the final diagnosis, our series comprised 32 cases of B-cell lymphomas, 38 cases of non-Hodgkin’s T-cell lymphomas and 51 cases of reactive lymphoid proliferations. Clonality testing was performed using the BIOMED-2 clonality assays. Results The determined sensitivity of the TCR assay was 91.9%, while the sensitivity of the IGH assay was 74.2%. The determined specificity of the IGH assay was 73.3% in the group of lymphomas and 87.2% in the group of reactive lesions. The determined specificity of the TCR assay was 62.5% in the group of lymphomas and 54.3% in the group of reactive lesions. Conclusions In the present study, we confirmed the utility of standardized BIOMED-2 clonality assays for the detection of clonality in a routine diagnostical setting of non-Hodgkin’s lymphomas. Reactions for the detection of the complete IGH rearrangements and reactions for the detection of the TCR rearrangements are a good choice for clonality testing of a wide range of lymphoid proliferations and specimen types while the reactions for the detection of incomplete IGH rearrangements have not shown any additional diagnostic value. PMID:24991205

Transcriptome Profiling to Understand the Effect of Citrus Rootstocks on the Growth of 'Shatangju' Mandarin.

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Liu, Xiang-Yu; Li, Juan; Liu, Meng-Meng; Yao, Qing; Chen, Jie-Zhong

2017-01-01

To obtain insight into potential mechanisms underlying the influence of rootstock on scion growth, we performed a comparative analysis of 'Shatangju' mandarin grafted onto 5 rootstocks: Fragrant orange (Citrus junons Sieb. ex. Tanaka), Red tangerine (Citrus reticulata Blanco), 'Shatangju' mandarin (Citrus reticulata Blanco), Rough lemon (Citrus jambhiri Lush) and Canton lemon (Citrus limonia Osbeck). The tree size of 'Shatangju' mandarin grafted onto Canton lemon and Rough lemon were the largest, followed by self-rooted rootstock trees, and the lowest tree sizes correspond to ones grafted on Red tangerine and Fragrant orange rootstocks. The levels of indoleacetic acid (IAA) and gibberellin (GA) were significantly and positively related to growth vigor. The differences of gene expression in leaves of trees grafted onto Red tangerine, Canton lemon and 'Shatangju' mandarin were analyzed by RNA-Seq. Results showed that more differentially expressed genes involved in oxidoreductase function, hormonal signal transduction and the glycolytic pathway were enriched in 'Red tangerine vs Canton lemon'. qRT-PCR analysis showed that expression levels of ARF1, ARF8, GH3 and IAA4 were negatively correlated with the growth vigor and IAA content. The metabolism of GA was influenced by the differential expression of KO1 and GA2OX1 in grafted trees. In addition, most of antioxidant enzyme genes were up-regulated in leaves of trees grafted onto Red tangerine, resulting in a higher peroxidase activity. We concluded that different rootstocks significantly affected the expression of genes involved in auxin signal transduction pathway and GA biosynthesis pathway in the grafted plants, and then regulated the hormone levels and their signal pathways.

Anatomical and Physiological Responses of Citrus Trees to Varying Boron Availability Are Dependent on Rootstock.

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Mesquita, Geisa L; Zambrosi, Fernando C B; Tanaka, Francisco A O; Boaretto, Rodrigo M; Quaggio, José A; Ribeiro, Rafael V; Mattos, Dirceu

2016-01-01

In Citrus, water, nutrient transport and thereby fruit production, are influenced among other factors, by the interaction between rootstock and boron (B) nutrition. This study aimed to investigate how B affects the anatomical structure of roots and leaves as well as leaf gas exchange in sweet orange trees grafted on two contrasting rootstocks in response to B supply. Plants grafted on Swingle citrumelo or Sunki mandarin were grown in a nutrient solution of varying B concentration (deficient, adequate, and excessive). Those grafted on Swingle were more tolerant to both B deficiency and toxicity than those on Sunki, as revealed by higher shoot and root growth. In addition, plants grafted on Sunki exhibited more severe anatomical and physiological damages under B deficiency, showing thickening of xylem cell walls and impairments in whole-plant leaf-specific hydraulic conductance and leaf CO2 assimilation. Our data revealed that trees grafted on Swingle sustain better growth under low B availablitlity in the root medium and still respond positively to increased B levels by combining higher B absorption and root growth as well as better organization of xylem vessels. Taken together, those traits improved water and B transport to the plant canopy. Under B toxicity, Swingle rootstock would also favor plant growth by reducing anatomical and ultrastructural damage to leaf tissue and improving water transport compared with plants grafted on Sunki. From a practical point of view, our results highlight that B management in citrus orchards shall take into account rootstock varieties, of which the Swingle rootstock was characterized by its performance on regulating anatomical and ultrastructural damages, improving water transport and limiting negative impacts of B stress conditions on plant growth.

Star Formation in Dwarf-Dwarf Mergers: Fueling Hierarchical Assembly

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Stierwalt, Sabrina; Johnson, K. E.; Kallivayalil, N.; Patton, D. R.; Putman, M. E.; Besla, G.; Geha, M. C.

2014-01-01

We present early results from the first systematic study a sample of isolated interacting dwarf pairs and the mechanisms governing their star formation. Low mass dwarf galaxies are ubiquitous in the local universe, yet the efficiency of gas removal and the enhancement of star formation in dwarfs via pre-processing (i.e. dwarf-dwarf interactions occurring before the accretion by a massive host) are currently unconstrained. Studies of Local Group dwarfs credit stochastic internal processes for their complicated star formation histories, but a few intriguing examples suggest interactions among dwarfs may produce enhanced star formation. We combine archival UV imaging from GALEX with deep optical broad- and narrow-band (Halpha) imaging taken with the pre- One Degree Imager (pODI) on the WIYN 3.5-m telescope and with the 2.3-m Bok telescope at Steward Observatory to confirm the presence of stellar bridges and tidal tails and to determine whether dwarf-dwarf interactions alone can trigger significant levels of star formation. We investigate star formation rates and global galaxy colors as a function of dwarf pair separation (i.e. the dwarf merger sequence) and dwarf-dwarf mass ratio. This project is a precursor to an ongoing effort to obtain high spatial resolution HI imaging to assess the importance of sequential triggering caused by dwarf-dwarf interactions and the subsequent affect on the more massive hosts that later accrete the low mass systems.

Effect of clonal integration on nitrogen cycling in rhizosphere of rhizomatous clonal plant, Phyllostachys bissetii, under heterogeneous light.

Science.gov (United States)

Li, Yang; Chen, Jing-Song; Xue, Ge; Peng, Yuanying; Song, Hui-Xing

2018-07-01

Clonal integration plays an important role in clonal plant adapting to heterogeneous habitats. It was postulated that clonal integration could exhibit positive effects on nitrogen cycling in the rhizosphere of clonal plant subjected to heterogeneous light conditions. An in-situ experiment was conducted using clonal fragments of Phyllostachys bissetii with two successive ramets. Shading treatments were applied to offspring or mother ramets, respectively, whereas counterparts were treated to full sunlight. Rhizomes between two successive ramets were either severed or connected. Extracellular enzyme activities and nitrogen turnover were measured, as well as soil properties. Abundance of functional genes (archaeal or bacterial amoA, nifH) in the rhizosphere of shaded, offspring or mother ramets were determined using quantitative polymerase chain reaction. Carbon or nitrogen availabilities were significantly influenced by clonal integration in the rhizosphere of shaded ramets. Clonal integration significantly increased extracellular enzyme activities and abundance of functional genes in the rhizosphere of shaded ramets. When rhizomes were connected, higher nitrogen turnover (nitrogen mineralization or nitrification rates) was exhibited in the rhizosphere of shaded offspring ramets. However, nitrogen turnover was significantly decreased by clonal integration in the rhizosphere of shaded mother ramets. Path analysis indicated that nitrogen turnover in the rhizosphere of shaded, offspring or mother ramets were primarily driven by the response of soil microorganisms to dissolved organic carbon or nitrogen. This unique in-situ experiment provided insights into the mechanism of nutrient recycling mediated by clonal integration. It was suggested that effects of clonal integration on the rhizosphere microbial processes were dependent on direction of photosynthates transport in clonal plant subjected to heterogeneous light conditions. Copyright © 2018 Elsevier B.V. All rights

NMR Spectroscopy Identifies Metabolites Translocated from Powdery Mildew Resistant Rootstocks to Susceptible Watermelon Scions.

Science.gov (United States)

Mahmud, Iqbal; Kousik, Chandrasekar; Hassell, Richard; Chowdhury, Kamal; Boroujerdi, Arezue F

2015-09-16

Powdery mildew (PM) disease causes significant loss in watermelon. Due to the unavailability of a commercial watermelon variety that is resistant to PM, grafting susceptible cultivars on wild resistant rootstocks is being explored as a short-term management strategy to combat this disease. Nuclear magnetic resonance-based metabolic profiles of susceptible and resistant rootstocks of watermelon and their corresponding susceptible scions (Mickey Lee) were compared to screen for potential metabolites related to PM resistance using multivariate principal component analysis. Significant score plot differences between the susceptible and resistant groups were revealed through Mahalanobis distance analysis. Significantly different spectral buckets and their corresponding metabolites (including choline, fumarate, 5-hydroxyindole-3-acetate, and melatonin) have been identified quantitatively using multivariate loading plots and verified by volcano plot analyses. The data suggest that these metabolites were translocated from the powdery mildew resistant rootstocks to their corresponding powdery mildew susceptible scions and can be related to PM disease resistance.

Host Range of a Population of Pratylenchus vulnus in Commercial Fruit, Nut, Citrus, and Grape Rootstocks in Spain.

Science.gov (United States)

Pinochet, J; Verdejo, S; Soler, A; Canals, J

1992-12-01

In a host-range study carried out under greenhouse conditions, a total of 37 commercial fruit tree, grape, and citrus rootstocks were tested for their reaction to a population of the lesion nematode, Pratylenchus vulnus, in Spain. Twenty-five rootstocks had a Pf/Pi > 1.5. These included almond (Desmayo Rojo, 1143), apple (EM-9, EM-106), avocado (Hass), cherry (Santa Lucia 64, Camil, M x M 14, Masto de Montafiana), grape (41-B, Fercal, Ritcher 110), hazelnut (Pauetet), loquat (Nadal), peach (Montclar, GF-305), pear (OHF-333), pistachio (P. atlantica, P. vera, P. terebinthus), plum (San Julian 655-2, Montizo, Pixy, Myrobalan 605), and walnut (Serf). The peach rootstock Nemaguard and the grape 161-49 had Pf/Pi between 1.0 and 1.5 (slightly higher than inoculation level). All the tested citrus (Alemow, rough lemon, Carrizo citrange, sour orange, Troyer citrange, Citrumelo), plus three grape (SO4, Vitis rupestris, 1103-P), and the olive rootstock Arbequina had a Pf/Pi < 1.0.

Evaluation of rough lemon (Citrus jambhiri Lush.) as rootstock for ...

African Journals Online (AJOL)

Lakesh.Sharma

2013-10-30

Oct 30, 2013 ... rootstock for salinity tolerance at seedling stage under in vitro conditions ... INTRODUCTION. Around the world, citrus is one of the .... to summarize the general effect of different concentrations of NaCl on rough lemon on the ...

Biosafety considerations of RNAi-mediated virus resistance in fruit-tree cultivars and in rootstock.

Science.gov (United States)

Lemgo, Godwin Nana Yaw; Sabbadini, Silvia; Pandolfini, Tiziana; Mezzetti, Bruno

2013-12-01

A major application of RNA interference (RNAi) is envisaged for the production of virus-resistant transgenic plants. For fruit trees, this remains the most, if not the only, viable option for the control of plant viral disease outbreaks in cultivated orchards, due to the difficulties associated with the use of traditional and conventional disease-control measures. The use of RNAi might provide an additional benefit for woody crops if silenced rootstock can efficiently transmit the silencing signal to non-transformed scions, as has already been demonstrated in herbaceous plants. This would provide a great opportunity to produce non-transgenic fruit from transgenic rootstock. In this review, we scrutinise some of the concerns that might arise with the use of RNAi for engineering virus-resistant plants, and we speculate that this virus resistance has fewer biosafety concerns. This is mainly because RNAi-eliciting constructs only express small RNA molecules rather than proteins, and because this technology can be applied using plant rootstock that can confer virus resistance to the scion, leaving the scion untransformed. We discuss the main biosafety concerns related to the release of new types of virus-resistant plants and the risk assessment approaches in the application of existing regulatory systems (in particular, those of the European Union, the USA, and Canada) for the evaluation and approval of RNAi-mediated virus-resistant plants, either as transgenic varieties or as plant virus resistance induced by transgenic rootstock.

Anatomical and Physiological Responses of Citrus Trees to Varying Boron Availability Is Dependent on Rootstock

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Geisa Lima Mesquita

2016-03-01

Full Text Available In Citrus, water, nutrient transport and thereby fruit production, are influenced among other factors, by the interaction between rootstock and boron (B nutrition. This study aimed to investigate how B affects the anatomical structure of roots and leaves as well as leaf gas exchange in sweet orange trees grafted on two contrasting rootstocks in response to B supply. Plants grafted on Swingle citrumelo or Sunki mandarin were grown in a nutrient solution of varying B concentration (deficient, adequate, and excessive. Those grafted on Swingle were more tolerant to both B deficiency and toxicity than those on Sunki, as revealed by higher shoot and root growth. In addition, plants grafted on Sunki exhibited more severe anatomical and physiological damages under B deficiency, showing thickening of xylem cell walls and impairments in whole-plant, leaf-specific hydraulic conductance and leaf CO2 assimilation. Our data revealed that trees grafted on Swingle sustain better growth under low B availablitlity in the root medium and still respond positively to increased B levels by combining higher B absorption and root growth as well as better organization of xylem vessels. Taken together, those traits improved water and B transport to the plant canopy. Under B toxicity, Swingle rootstock would also favor plant growth by reducing anatomical and ultrastructural damage to leaf tissue and improving water transport compared with plants grafted on Sunki. From a practical point of view, our results highlight that B management in citrus orchards shall take into account rootstock varieties, of which the Swingle rootstock was characterized by its performance on regulating anatomical and ultrastructural damages, improving water transport and limiting negative impacts of B stress conditions on plant growth.

An Invasive Clonal Plant Benefits from Clonal Integration More than a Co-Occurring Native Plant in Nutrient-Patchy and Competitive Environments

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You, Wenhua; Fan, Shufeng; Yu, Dan; Xie, Dong; Liu, Chunhua

2014-01-01

Many notorious invasive plants are clonal, however, little is known about the different roles of clonal integration effects between invasive and native plants. Here, we hypothesize that clonal integration affect growth, photosynthetic performance, biomass allocation and thus competitive ability of invasive and native clonal plants, and invasive clonal plants benefit from clonal integration more than co-occurring native plants in heterogeneous habitats. To test these hypotheses, two stoloniferous clonal plants, Alternanthera philoxeroides (invasive), Jussiaea repens (native) were studied in China. The apical parts of both species were grown either with or without neighboring vegetation and the basal parts without competitors were in nutrient- rich or -poor habitats, with stolon connections were either severed or kept intact. Competition significantly reduced growth and photosynthetic performance of the apical ramets in both species, but not the biomass of neighboring vegetation. Without competition, clonal integration greatly improved the growth and photosynthetic performance of both species, especially when the basal parts were in nutrient-rich habitats. When grown with neighboring vegetation, growth of J. repens and photosynthetic performance of both species were significantly enhanced by clonal integration with the basal parts in both nutrient-rich and -poor habitats, while growth and relative neighbor effect (RNE) of A. philoxeroides were greatly improved by clonal integration only when the basal parts were in nutrient-rich habitats. Moreover, clonal integration increased A. philoxeroides's biomass allocation to roots without competition, but decreased it with competition, especially when the basal ramets were in nutrient-rich sections. Effects of clonal integration on biomass allocation of J. repens was similar to that of A. philoxeroides but with less significance. These results supported our hypothesis that invasive clonal plants A. philoxeroides benefits

Rootstock effects on fruit quality among 'Ray Ruby' grapefruit trees grown in the Indian River district of Florida

Science.gov (United States)

The objective of this experiment was to compare fruit quality parameters of ‘Ray Ruby’ grapefruit grown on seven rootstocks. Four recent releases from the USDA rootstock breeding program, US-852, US-897, US-942 and US-812 (all Citrus reticulata x P. trifoliata hybrids), X639 (C. reticulata x P. tri...

Transcriptome Profiling to Understand the Effect of Citrus Rootstocks on the Growth of ‘Shatangju’ Mandarin

Science.gov (United States)

Liu, Meng-Meng; Yao, Qing; Chen, Jie-Zhong

2017-01-01

To obtain insight into potential mechanisms underlying the influence of rootstock on scion growth, we performed a comparative analysis of ‘Shatangju’ mandarin grafted onto 5 rootstocks: Fragrant orange (Citrus junons Sieb. ex. Tanaka), Red tangerine (Citrus reticulata Blanco), ‘Shatangju’ mandarin (Citrus reticulata Blanco), Rough lemon (Citrus jambhiri Lush) and Canton lemon (Citrus limonia Osbeck). The tree size of ‘Shatangju’ mandarin grafted onto Canton lemon and Rough lemon were the largest, followed by self-rooted rootstock trees, and the lowest tree sizes correspond to ones grafted on Red tangerine and Fragrant orange rootstocks. The levels of indoleacetic acid (IAA) and gibberellin (GA) were significantly and positively related to growth vigor. The differences of gene expression in leaves of trees grafted onto Red tangerine, Canton lemon and ‘Shatangju’ mandarin were analyzed by RNA-Seq. Results showed that more differentially expressed genes involved in oxidoreductase function, hormonal signal transduction and the glycolytic pathway were enriched in ‘Red tangerine vs Canton lemon’. qRT-PCR analysis showed that expression levels of ARF1, ARF8, GH3 and IAA4 were negatively correlated with the growth vigor and IAA content. The metabolism of GA was influenced by the differential expression of KO1 and GA2OX1 in grafted trees. In addition, most of antioxidant enzyme genes were up-regulated in leaves of trees grafted onto Red tangerine, resulting in a higher peroxidase activity. We concluded that different rootstocks significantly affected the expression of genes involved in auxin signal transduction pathway and GA biosynthesis pathway in the grafted plants, and then regulated the hormone levels and their signal pathways. PMID:28081213

Advances in apple culture worldwide

Directory of Open Access Journals (Sweden)

Terence Robinson

2011-10-01

Full Text Available Over the last 60 years, planting densities for apple have increased as improved management systems have been developed. Dwarfing rootstocks have been the key to the dramatic changes in tree size, spacing and early production. The Malling series of dwarfing rootstocks (M.9 and M.26 have been the most important dwarfing rootstocks in the world but are poorly adapted in some areas of the world and they are susceptible to the bacterial disease fire blight and the soil disease complex, apple replant disease which limits their uses in some areas. Rootstock breeding programs in several parts of the world are developing improved rootstocks with resistance to fire blight, and replant disease, and improved cold hardiness and yield efficiency. A second important trend has been the increasing importance of new cultivars. New cultivars have provided opportunities for higher prices until they are over-produced. A new trend is the "variety club" in which variety owners manage the production and marketing of a new unique cultivar to bring higher prices to the growers and variety owners. This has led to many fruit growers being unable to plant or grow some new cultivars. Important rootstock and cultivar genes have been mapped and can be used in marker assisted selection of future rootstock and cultivar selections. Other important improvements in apple culture include the development of pre-formed trees, the development of minimal pruning strategies and limb angle bending which have also contributed to the dramatic changes in early production in the 2nd-5th years after planting. Studies on light interception and distribution have led to improved tree forms with better fruit quality. Simple pruning strategies and labor positioning platform machines have resulted in partial mechanization of pruning which has reduced management costs. Improved plant growth regulators for thinning and the development of a thinning prediction model based on tree carbohydrate balance

Involvement of rootstocks and their hydraulic conductance in the ...

African Journals Online (AJOL)

Improving drought resistance of rubber trees has become a pressing issue with the extension of rubber plantations and the prevalence of seasonal drought. Root system is vital to water and nutrients uptake of all plants, therefore, rootstocks could play decisive roles in drought resistance of grafted rubber trees on a specific ...

[Effects of rootstocks on the growth and berry quality of Vitis vinifera cv. Cabernet Sauvignon grapevine in Changli zone, Hebei Province, China].

Science.gov (United States)

Li, Min-min; Yuan, Jun-wei; Liu, Chang-jiang; Han, Bin; Huang, Jia-zhen; Guo, Zi-juan; Zhao, Sheng-iian

2016-01-01

Cabernet Sauvignon grafted onto seven rootstocks 188-08, 5BB, SO4, 3309C, 110R, 5C and 101-14M, with the own-rooted vines as control, were investigated to study the effects of different rootstocks on the growth, fruit quality and yield of Cabernet Sauvignon in Changli zone, Hebei Province, China. The results showed that Cabernet Sauvignon grafted on 5BB and 5C significantly increased the trunk diameter, and 5C significantly increased one-year-old shoot diameter. 188-08, 5BB and 5C as rootstock obviously improved berry soluble solid content, in addition 188- 08 and 5BB significantly increased berry reducing sugar content. The vines on 101-14M and 3309C significantly decreased berry titratable acid content. The rootstock 5C and 101-14M significantly raised grape skin phenol and anthocyanin contents, and rootstock 101-14M significantly increased tannin content in grape skin. Cabernet Sauvignon grafted onto 3309C, 110R, 5C and 101-14M obviously got higher yield per vine than own-rooted vines. Growing parameter, grape quality index and yield per vine grafted on seven rootstocks and own-rooted vine were synthetically evaluated by fuzzy evaluation method, and the synthetical effects of vine grafted on seven rootstocks were better than own-rooted vine, with the order of scores from high to low as 5C, 101-14M, 3309C, 5BB, 188-08, 110R and SO4 under Changli unique climate and environment conditions.

Infrared Colors of Dwarf-Dwarf Galaxy Interactions

Science.gov (United States)

Liss, Sandra; Stierwalt, Sabrina; Johnson, Kelsey; Patton, Dave; Kallivayalil, Nitya

2015-10-01

We request Spitzer Warm Mission IRAC Channel 1 & 2 imaging for a sample of 60 isolated dwarf galaxy pairs as a key component of a larger, multi-wavelength effort to understand the role low-mass mergers play in galaxy evolution. A systematic study of dwarf-dwarf mergers has never been done, and we wish to characterize the impact such interactions have on fueling star formation in the nearby universe. The Spitzer imaging proposed here will allow us to determine the extent to which the 3.6 and 4.5 mum bands are dominated by stellar light and investigate a) the extent to which interacting pairs show IR excess and b) whether the excess is related to the pair separation. Second, we will use this IR photometry to constrain the processes contributing to the observed color excess and scatter in each system. We will take advantage of the wealth of observations available in the Spitzer Heritage Archive for 'normal' non-interacting dwarfs by comparing the stellar populations of those dwarfs with the likely interacting dwarfs in our sample. Ultimately, we can combine the Spitzer imaging proposed here with our current, ongoing efforts to obtain groundbased optical photometry to model the star formation histories of these dwarfs and to help constrain the timescales and impact dwarf-dwarf mergers have on fueling star formation. The sensitivity and resolution offered by Spitzer are necessary to determine the dust properties of these interacting systems, and how these properties vary as a function of pair separation, mass ratio, and gas fraction.

Satellite dwarf galaxies in a hierarchical universe: the prevalence of dwarf-dwarf major mergers

International Nuclear Information System (INIS)

Deason, Alis; Wetzel, Andrew; Garrison-Kimmel, Shea

2014-01-01

Mergers are a common phenomenon in hierarchical structure formation, especially for massive galaxies and clusters, but their importance for dwarf galaxies in the Local Group remains poorly understood. We investigate the frequency of major mergers between dwarf galaxies in the Local Group using the ELVIS suite of cosmological zoom-in dissipationless simulations of Milky Way- and M31-like host halos. We find that ∼10% of satellite dwarf galaxies with M star > 10 6 M ☉ that are within the host virial radius experienced a major merger of stellar mass ratio closer than 0.1 since z = 1, with a lower fraction for lower mass dwarf galaxies. Recent merger remnants are biased toward larger radial distance and more recent virial infall times, because most recent mergers occurred shortly before crossing within the virial radius of the host halo. Satellite-satellite mergers also occur within the host halo after virial infall, catalyzed by the large fraction of dwarf galaxies that fell in as part of a group. The merger fraction doubles for dwarf galaxies outside of the host virial radius, so the most distant dwarf galaxies in the Local Group are the most likely to have experienced a recent major merger. We discuss the implications of these results on observable dwarf merger remnants, their star formation histories, the gas content of mergers, and massive black holes in dwarf galaxies.

Grapevine rootstocks differentially affect the rate of ripening and modulate auxin-related genes in Cabernet Sauvignon berries

Directory of Open Access Journals (Sweden)

Massimiliano eCorso

2016-02-01

Full Text Available In modern viticulture, grafting commercial grapevine varieties on interspecific rootstocks is a common practice required for conferring resistance to many biotic and abiotic stresses. Nevertheless, the use of rootstocks to gain these essential traits is also known to impact grape berry development and quality, although the underlying mechanisms are still poorly understood. In grape berries, the onset of ripening (véraison is regulated by a complex network of mobile signals including hormones such as auxins, ethylene, abscisic acid and brassinosteroids. Recently, a new rootstock, designated M4, was selected based on its enhanced tolerance to water stress and medium vigour. This study investigates the effect of M4 on Cabernet Sauvignon (CS berry development in comparison to the commercial 1103P rootstock. Physical and biochemical parameters showed that the ripening rate of CS berries is faster when grafted onto M4. A multifactorial analysis performed on mRNA-Seq data obtained from skin and pulp of berries grown in both graft combinations revealed that genes controlling auxin action (ARF and Aux/IAA represent one of main categories affected by the rootstock genotype. Considering that the level of auxin tightly regulates the transcription of these genes, we investigated the behaviour of the main gene families involved in auxin biosynthesis and conjugation. Molecular and biochemical analyses confirmed a link between the rate of berry development and the modulation of auxin metabolism. Moreover the data indicate that this phenomenon appears to be particularly pronounced in skin tissue in comparison to the flesh.

Grapevine Rootstocks Differentially Affect the Rate of Ripening and Modulate Auxin-Related Genes in Cabernet Sauvignon Berries.

Science.gov (United States)

Corso, Massimiliano; Vannozzi, Alessandro; Ziliotto, Fiorenza; Zouine, Mohamed; Maza, Elie; Nicolato, Tommaso; Vitulo, Nicola; Meggio, Franco; Valle, Giorgio; Bouzayen, Mondher; Müller, Maren; Munné-Bosch, Sergi; Lucchin, Margherita; Bonghi, Claudio

2016-01-01

In modern viticulture, grafting commercial grapevine varieties on interspecific rootstocks is a common practice required for conferring resistance to many biotic and abiotic stresses. Nevertheless, the use of rootstocks to gain these essential traits is also known to impact grape berry development and quality, although the underlying mechanisms are still poorly understood. In grape berries, the onset of ripening (véraison) is regulated by a complex network of mobile signals including hormones such as auxins, ethylene, abscisic acid, and brassinosteroids. Recently, a new rootstock, designated M4, was selected based on its enhanced tolerance to water stress and medium vigor. This study investigates the effect of M4 on Cabernet Sauvignon (CS) berry development in comparison to the commercial 1103P rootstock. Physical and biochemical parameters showed that the ripening rate of CS berries is faster when grafted onto M4. A multifactorial analysis performed on mRNA-Seq data obtained from skin and pulp of berries grown in both graft combinations revealed that genes controlling auxin action (ARF and Aux/IAA) represent one of main categories affected by the rootstock genotype. Considering that the level of auxin tightly regulates the transcription of these genes, we investigated the behavior of the main gene families involved in auxin biosynthesis and conjugation. Molecular and biochemical analyses confirmed a link between the rate of berry development and the modulation of auxin metabolism. Moreover, the data indicate that this phenomenon appears to be particularly pronounced in skin tissue in comparison to the flesh.

Populations in clonal plants

Directory of Open Access Journals (Sweden)

Jussi Tammisola

1986-12-01

Full Text Available Population phenomena in higher plants are reviewed critically, particularly in relation to clonality. An array of concepts used in the field are discussed. In contrast to animals, higher plants are modular in structure. Plant populations show hierarchy at two levels: ramets and genets. In addition, their demography is far more complicated, since even the direction of development of a ramet may change by rejuvenation. Therefore, formulae concerning animal populations often require modification for plants. Furthermore, at the zygotic stage, higher plants are generally less mobile than animals. Accordingly, their population processes tend to be more local. Most populations of plants have a genetic structure: alleles and genotypes are spatially aggregated. Due to the short-ranged foraging behaviour of pollinators, genetically non-random pollination prevails. A generalized formula for parent-offspring dispersal variance is derived. It is used to analyze the effect of clonality on genetic patchiness in populations. In self-compatible species, an increase in clonality will tend to increase the degree of patchiness, while in self-incompatible species a decrease may result. Examples of population structure studies in different species are presented. A considerable degree of genetic variation appears to be found also in the populations of species with a strong allocation of resources to clonal growth or apomictic seed production. Some consequences of clonality are considered from the point of view of genetic conservation and plant breeding.

Clonal growth and plant species abundance.

Science.gov (United States)

Herben, Tomáš; Nováková, Zuzana; Klimešová, Jitka

2014-08-01

Both regional and local plant abundances are driven by species' dispersal capacities and their abilities to exploit new habitats and persist there. These processes are affected by clonal growth, which is difficult to evaluate and compare across large numbers of species. This study assessed the influence of clonal reproduction on local and regional abundances of a large set of species and compared the predictive power of morphologically defined traits of clonal growth with data on actual clonal growth from a botanical garden. The role of clonal growth was compared with the effects of seed reproduction, habitat requirements and growth, proxied both by LHS (leaf-height-seed) traits and by actual performance in the botanical garden. Morphological parameters of clonal growth, actual clonal reproduction in the garden and LHS traits (leaf-specific area - height - seed mass) were used as predictors of species abundance, both regional (number of species records in the Czech Republic) and local (mean species cover in vegetation records) for 836 perennial herbaceous species. Species differences in habitat requirements were accounted for by classifying the dataset by habitat type and also by using Ellenberg indicator values as covariates. After habitat differences were accounted for, clonal growth parameters explained an important part of variation in species abundance, both at regional and at local levels. At both levels, both greater vegetative growth in cultivation and greater lateral expansion trait values were correlated with higher abundance. Seed reproduction had weaker effects, being positive at the regional level and negative at the local level. Morphologically defined traits are predictive of species abundance, and it is concluded that simultaneous investigation of several such traits can help develop hypotheses on specific processes (e.g. avoidance of self-competition, support of offspring) potentially underlying clonal growth effects on abundance. Garden

Clonal sets of a binary relation

Science.gov (United States)

Zedam, Lemnaouar; Pérez-Fernández, Raúl; Bouremel, Hassane; De Baets, Bernard

2018-05-01

In a recent paper, we have introduced the notion of clone relation of a given binary relation. Intuitively, two elements are said to be "clones" if they are related in the same way w.r.t. every other element. In this paper, we generalize this notion from pairs of elements to sets of elements of any cardinality, resulting in the introduction of clonal sets. We investigate the most important properties of clonal sets, paying particular attention to the introduction of the clonal closure operator, to the analysis of the (lattice) structure of the set of clonal sets and to a distance metric expressing how close two elements are to being clones.

The effect of water stress on some morphological, physiological, and biochemical characteristics and bud success on apple and quince rootstocks.

Science.gov (United States)

Bolat, Ibrahim; Dikilitas, Murat; Ercisli, Sezai; Ikinci, Ali; Tonkaz, Tahsin

2014-01-01

The effects of different water stress (control, medium, and severe) on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67%) and Santa Maria/MA (70.33% and 15.33%) combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present.

The Effect of Water Stress on Some Morphological, Physiological, and Biochemical Characteristics and Bud Success on Apple and Quince Rootstocks

Directory of Open Access Journals (Sweden)

Ibrahim Bolat

2014-01-01

Full Text Available The effects of different water stress (control, medium, and severe on some morphological, physiological, and biochemical characteristics and bud success of M9 apple and MA quince rootstocks were determined. The results showed that water stress significantly affected most morphological, physiological, and biochemical characteristics as well as budding success on the both rootstocks. The increasing water stress decreased the relative shoot length, diameter, and plant total fresh and dry weights. Leaf relative water content and chlorophyll index decreased while electrolyte leakage increased with the increase of water stress in both rootstocks. An increase in water stress also resulted in reduction in budding success in Vista Bella/M9 (79.33% and 46.67% and Santa Maria/MA (70.33% and 15.33% combinations. However, the water stress in Santa Maria/MA was more prominent. The increase in water stress resulted in higher peroxidase activities as well as phenol contents in both rootstocks. Although catalase activity, anthocyanin, and proline contents increased with the impact of stress, this was not statistically significant. The results suggest that the impact of stress increased with the increase of water stress; therefore, growers should be careful when using M9 and MA rootstocks in both nursery and orchards where water scarcity is present.

Satellite dwarf galaxies in a hierarchical universe: the prevalence of dwarf-dwarf major mergers

Energy Technology Data Exchange (ETDEWEB)

Deason, Alis [Department of Astronomy and Astrophysics, University of California Santa Cruz, Santa Cruz, CA (United States); Wetzel, Andrew [TAPIR, California Institute of Technology, Pasadena, CA (United States); Garrison-Kimmel, Shea, E-mail: alis@ucolick.org [Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, CA (United States)

2014-10-20

Mergers are a common phenomenon in hierarchical structure formation, especially for massive galaxies and clusters, but their importance for dwarf galaxies in the Local Group remains poorly understood. We investigate the frequency of major mergers between dwarf galaxies in the Local Group using the ELVIS suite of cosmological zoom-in dissipationless simulations of Milky Way- and M31-like host halos. We find that ∼10% of satellite dwarf galaxies with M {sub star} > 10{sup 6} M {sub ☉} that are within the host virial radius experienced a major merger of stellar mass ratio closer than 0.1 since z = 1, with a lower fraction for lower mass dwarf galaxies. Recent merger remnants are biased toward larger radial distance and more recent virial infall times, because most recent mergers occurred shortly before crossing within the virial radius of the host halo. Satellite-satellite mergers also occur within the host halo after virial infall, catalyzed by the large fraction of dwarf galaxies that fell in as part of a group. The merger fraction doubles for dwarf galaxies outside of the host virial radius, so the most distant dwarf galaxies in the Local Group are the most likely to have experienced a recent major merger. We discuss the implications of these results on observable dwarf merger remnants, their star formation histories, the gas content of mergers, and massive black holes in dwarf galaxies.

THE FORNAX DWARF GALAXY AS A REMNANT OF RECENT DWARF-DWARF MERGING IN THE LOCAL GROUP

International Nuclear Information System (INIS)

Yozin, C.; Bekki, K.

2012-01-01

We present results from the first numerical analysis to support the hypothesis, first proposed in Coleman et al., that the Fornax dwarf galaxy was formed from the minor merging of two dwarfs about 2 Gyr ago. Using orbits for the Fornax dwarf that are consistent with the latest proper motion measurements, our dynamical evolution models show that the observed asymmetric shell-like substructures can be formed from the remnant of a smaller dwarf during minor merging. These models also predict the formation of diffuse stellar streams. We discuss how these stellar substructures depend on model parameters of dwarf-dwarf merging, and how the intermediate-age subpopulations found in the vicinity of these substructures may be formed from gas accretion in past merger events. We also suggest that one of Fornax's globular clusters originates from a merged dwarf companion, and demonstrate where as yet undetected tidal streams or H I gas formed from the dwarf merging may be found in the outer halo of the Galaxy.

Clonal hematopoiesis in acquired aplastic anemia

OpenAIRE

Ogawa, Seishi

2016-01-01

Clonal hematopoiesis (CH) in aplastic anemia (AA) has been closely linked to the evolution of late clonal disorders, including paroxysmal nocturnal hemoglobinuria and myelodysplastic syndromes (MDS)/acute myeloid leukemia (AML), which are common complications after successful immunosuppressive therapy (IST). With the advent of high-throughput sequencing of recent years, the molecular aspect of CH in AA has been clarified by comprehensive detection of somatic mutations that drive clonal evolut...

ROOTSTOCK-SCION INTERACTION: 2. EFFECT ON THE COMPOSITION OF CABERNET SAUVIGNON GRAPE MUST

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ALBERTO MIELE

2017-08-01

Full Text Available ABSTRACT The interaction between rootstock, scion and the environment may induce different responses to the grapevine physiology and, consequently, to the grape composition. The vineyards of Serra Gaúcha, Brazil, are established in different soil types, each with different morphological and physicochemical attributes. Moreover, the grapevines are grafted onto a diversity of rootstocks. Therefore, this study aimed to determine the effect of 15 rootstocks in the composition of the Cabernet Sauvignon (CS grape must. The following rootstocks were used: Rupestris du Lot, 101-14 Mgt., 3309 C, 420A Mgt., 5BB K, 161-49 C, SO4, Solferino, 1103 P, 99 R, 110 R, Gravesac, Fercal, Dogridge and Isabel, featuring some genetic diversity altogether. The experimental design was in randomized blocks with 15 treatments, three replicates, 10 vines per plot. The grapes were harvested at maturity for four years, and then crushed for winemaking. Next, the grape musts were centrifuged to separate the solid phase from the liquid phase, which was used for analyses related to sugar, acidity and minerals. The data were submitted to correlation analysis and Principal Component Analysis. The main results from the average of four years show that, in general, the grape musts of the CS/101-14 Mgt., CS/161-49 C, CS/3309 C, CS/Rupestris du Lot and CS/Gravesac combinations had high values of density, total soluble solids, pH and °Brix/titratable acidity ratio, and low titratable acidity, which was high with CS/99 R, CS/110 R, CS/Dogridge and CS/1103 P. Potassium had higher concentrations in the grape musts of CS/SO4 and CS/5BB K. Titratable acidity did not correlate with density and total soluble solids, but positively correlated with yield. Density, total soluble solids, and the concentration of potassium were positively correlated with pH.

Rootstock control of scion transpiration and its acclimation to water deficit are controlled by different genes.

Science.gov (United States)

Marguerit, Elisa; Brendel, Oliver; Lebon, Eric; Van Leeuwen, Cornelis; Ollat, Nathalie

2012-04-01

The stomatal control of transpiration is one of the major strategies by which plants cope with water stress. Here, we investigated the genetic architecture of the rootstock control of scion transpiration-related traits over a period of 3 yr. The rootstocks studied were full sibs from a controlled interspecific cross (Vitis vinifera cv. Cabernet Sauvignon × Vitis riparia cv. Gloire de Montpellier), onto which we grafted a single scion genotype. After 10 d without stress, the water supply was progressively limited over a period of 10 d, and a stable water deficit was then applied for 15 d. Transpiration rate was estimated daily and a mathematical curve was fitted to its response to water deficit intensity. We also determined δ(13) C values in leaves, transpiration efficiency and water extraction capacity. These traits were then analysed in a multienvironment (year and water status) quantitative trait locus (QTL) analysis. Quantitative trait loci, independent of year and water status, were detected for each trait. One genomic region was specifically implicated in the acclimation of scion transpiration induced by the rootstock. The QTLs identified colocalized with genes involved in water deficit responses, such as those relating to ABA and hydraulic regulation. Scion transpiration rate and its acclimation to water deficit are thus controlled genetically by the rootstock, through different genetic architectures. © 2012 INRA. New Phytologist © 2012 New Phytologist Trust.

Optimization of Factors Affecting in vitro Propagation of ‘Myrobalan 29c’ Rootstock

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zahra shabani

2018-02-01

Full Text Available Introduction: This study was conducted aimed to consider the effects of culture medium and the concentration of growth regulators on proliferation, rooting and the acclimatization of Myrobalan29C. This study was performed as a factorial experiment in a completely randomized design (CRD with four replications where each plot contained five explants. Given the role of trees rootstock of growth rate vegetative in the early maturity٫ yield and disease resistance will be suitable rootstock that has an important role in program garden management. In total rootstock of fruit trees have be propagation sexual and asexual methods, however٫ given that in sexual reproduction the resulting dispersion characteristics and the resulting seedlings changed by genetics, it is tried for decades to asexual propagation methods in specially tissue culture methods healthy rootstock for mass propagation and used the development of orchards. Seedling rootstock Myrobalan had been used in the past. The rootstock can be positive features cited the ease of access, to be cheap, good yields after maturity. In study, the effects of NAA and BAP on proliferation of Gisala5 rootstock showed the most shoot treated in mediacontaining 1mg/l BAP. Investigated Chinese plum in vitro micropropagation showed that 1/2 MS media had the highest percentage rooting, and acclimatization rooted plantlets to greenhouse conditions was using the system miss successfully. Due to the importance and essential to achieve an efficient protocol for the mass propagation of Myrobalan 29C in Iran, this study was conducted with the main purpose of evaluating the most suitable media culture and plant growth regulators in micropropagation of Myrobalan 29C. Material and methods: The explants were collected from shoots of Myrobalan 29C rootstock maintained in the experimental greenhouse of Khorasan Razavi Agricultural and Natural Resources Research Centre (of Mashhad, Iran, on June 25, 2013. The explants were

Management of chili pepper root rot and wilt (caused by Phytophthora nicotianae by grafting onto resistant rootstock

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Mourad SAADOUN

2013-05-01

Full Text Available Root rot and plant wilting caused by Phytophthora nicotianae is a severe disease of chili pepper (Capsicum annuum L. in open fields and under greenhouse production in Tunisia. Chili pepper grafting for disease manage- ment is attracting increased interest in recent years. Using the tube grafting technique, different compatible scion/rootstock combinations were obtained with the wild-type pepper SCM334 and the local chili pepper cultivars ‘Beldi’ and ‘Baker’. SCM334 was resistant to P. nicotianae, while the cultivars Beldi and Baker were susceptible. Plant inoculations were performed with P. nicotianae zoospores, and severity of root rot was rated 30 days post- inoculation using a 0 (healthy plant to 5 (dead plant severity score. On SCM334 rootstock and with ‘Beldi’ or ‘Baker’ scions, the intensity of root rot was very low (mean score 0.1–0.2 and plants were healthy. However, with Baker or Beldi rootstocks and SCM334 scions, root rot was severe (mean score 3.1–4.6, leading to high numbers of wilting and dead plants. This severe root rot was similar to that observed on non-grafted plants of ‘Baker’ and ‘Beldi’ inoculated with the pathogen. Under greenhouse conditions, measurements of agronomic characters indicated non-consistent improvement of these features on the scion cultivar when SCM334 was the rootstock. Since plant foliage is not attacked by this pathogen, these results show that susceptible chili pepper scions grafted onto SCM334 rootstocks could be used for root rot management and improvement of pepper yields in P. nicotianae infested soils.

The evolutionary ecology of clonally propagated domesticated plants.

Science.gov (United States)

McKey, Doyle; Elias, Marianne; Pujol, Benoît; Duputié, Anne

2010-04-01

While seed-propagated crops have contributed many evolutionary insights, evolutionary biologists have often neglected clonally propagated crops. We argue that widespread notions about their evolution under domestication are oversimplified, and that they offer rich material for evolutionary studies. The diversity of their wild ancestors, the diverse ecologies of the crop populations themselves, and the intricate mix of selection pressures, acting not only on the parts harvested but also on the parts used by humans to make clonal propagules, result in complex and diverse evolutionary trajectories under domestication. We examine why farmers propagate some plants clonally, and discuss the evolutionary dynamics of sexual reproduction in clonal crops. We explore how their mixed clonal/sexual reproductive systems function, based on the sole example studied in detail, cassava (Manihot esculenta). Biotechnology is now expanding the number of clonal crops, continuing the 10 000-yr-old trend to increase crop yields by propagating elite genotypes. In an era of rapid global change, it is more important than ever to understand how the adaptive potential of clonal crops can be maintained. A key component of strategies for preserving this adaptive potential is the maintenance of mixed clonal/sexual systems, which can be achieved by encouraging and valuing farmer knowledge about the sexual reproductive biology of their clonal crops.

The Effect of Polyamine Applications on Root Enhancement of Pistachio Seedling Rootstocks of ‘Badamy-E- Riz’

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S. Sedaghat

2014-02-01

Full Text Available Pistacia vera cv Badami-e-Riz is the most important and popular rootstock in Iran, which tolerate salinity soil and phytophthora fungi but its root is less affected. In addition this rootstock is susceptible to excessive B and water deficient. This rootstock has a taproot rooting system without any lateral root. So this study was conducted to evaluate the effects of various concentrations and application methods of polyamines on root regeneration of transplanted bare-rooted ‘Badami-e-Riz’ pistachio rootstocks.The result showed that spermidine at concentration of 2 mM as foliar application method significantly enhanced root length and root diameter in ‘Badami-e-Riz’. Furthermore, the fresh weight of root was increased by 4 mM spermidine by foliar application and 2 mM spermidine by interaction of root tip cut and root dip method, significantly increased dry weight of root and root number in ‘Badami-e-Riz’. Besides, by the use of these chemicals, the survival percentage of seedlings was maintained in higher value. Results suggested that polyamine application was effective to increase lateral root formation and improved root regeneration. Therefore, it would be useful to help the survival of seedlings following transplanting.

Zero-inflated beta regression model for leaf citrus canker incidence in orange genotypes grafted onto different rootstocks

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Oilson Alberto Gonzatto Junior

2017-06-01

Full Text Available Data with excess zeros are frequently found in practice, and the recommended analysis is to use models that adequately address the counting of zero observations. In this study, the Zero Inflated Beta Regression Model (BeZI was used on experimental data to describe the mean incidence of leaf citrus canker in orange groves under the influence of genotype and rootstocks of origin. Based on the model, it was possible to quantify the odds that a null observation to mean incidence comes from a particular plant according to genotype and rootstock, and estimate its expected value according to this combination. Laranja Caipira rootstock proved to be the most resistant to leaf citrus canker as well as Limão Cravo proved to be the most fragile. The Ipiguá IAC, Arapongas, EEL and Olímpia genotypes have statistically equivalent chances.

Extensive clonal spread and extreme longevity in saw palmetto, a foundation clonal plant.

Science.gov (United States)

Takahashi, Mizuki K; Horner, Liana M; Kubota, Toshiro; Keller, Nathan A; Abrahamson, Warren G

2011-09-01

The lack of effective tools has hampered out ability to assess the size, growth and ages of clonal plants. With Serenoa repens (saw palmetto) as a model, we introduce a novel analytical framework that integrates DNA fingerprinting and mathematical modelling to simulate growth and estimate ages of clonal plants. We also demonstrate the application of such life-history information of clonal plants to provide insight into management plans. Serenoa is an ecologically important foundation species in many Southeastern United States ecosystems; yet, many land managers consider Serenoa a troublesome invasive plant. Accordingly, management plans have been developed to reduce or eliminate Serenoa with little understanding of its life history. Using Amplified Fragment Length Polymorphisms, we genotyped 263 Serenoa and 134 Sabal etonia (a sympatric non-clonal palmetto) samples collected from a 20 × 20 m study plot in Florida scrub. Sabal samples were used to assign small field-unidentifiable palmettos to Serenoa or Sabal and also as a negative control for clone detection. We then mathematically modelled clonal networks to estimate genet ages. Our results suggest that Serenoa predominantly propagate via vegetative sprouts and 10,000-year-old genets may be common, while showing no evidence of clone formation by Sabal. The results of this and our previous studies suggest that: (i) Serenoa has been part of scrub associations for thousands of years, (ii) Serenoa invasion are unlikely and (ii) once Serenoa is eliminated from local communities, its restoration will be difficult. Reevaluation of the current management tools and plans is an urgent task. © 2011 Blackwell Publishing Ltd.

Rootstock effects on almond leaf scorch disease incidence and severity

Science.gov (United States)

A five-year field study was conducted to evaluate effects of duration and exclusion of Xylella fastidiosa infections on young almond tree performance and their links to tree vigor. ‘Nemaguard’, ‘Okinawa’, ‘Nonpareil’, and Y119 were used as rootstocks for almond scion ‘Sonora’. Among X.fastidiosa-inf...

Tangerineiras como porta-enxertos para laranjeira 'Pêra' Mandarins as rootstocks for 'Pêra' sweet orange trees

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Jorgino Pompeu Junior

2008-08-01

Sao Paulo state, Brazil, under Cwa climatic conditions, and managed without irrigation. Tristeza and blight diseases are endemic in the area. Trees on Africa do Sul, Xienkhouanga, Empress, Cleopatra, Wildt and 117.477 cultivars, produced the highest cumulative yields in the first four crops and in the ninth crop. Regardless of the rootstock tested no significant variation on fruit quality was observed, but 'Cleopatra' mandarin induced earlier maturation of fruit than the others roostocks. Only 'Szwinkon' x 'Szinkon-tizon' rootstocks induced dwarfed trees. 'Xienkhouanga', 117.477, 'Africa do Sul', 'Cleopatra', 'Empress', 'Wildt' and 'Szinkon' x 'Tizon' induced the highest fruit and soluble solids production by tree in the 1996-1999 period. No one trees showed symptoms of tristeza, declinio/blight or bud-union-ring symptom of incompatibility.

comparative study with commercial rootstocks to determine the tolerance to heavy metal (Pb in the drought and salt stress tolerant eggplant breeding lines

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Mevlüde Nur TOPAL

2017-06-01

Full Text Available Negative effects of heavy metals on plants are peroxidation of lipids in cell membranes, production of free oxygen radicals, disorders in photosynthesis, damages in DNAs and as a result death of the cell. Plant development, productivity and quality of the fruits are decreased in the plants that are exposed to Pb stress which is one of the most toxic heavy metals. Usage of rootstocks which is mainly used against biotic stress conditions also seems to be defined as a solution to abiotic stress conditions such as heavy metal stresses. In eggplant production, wild species and hybrids are used as rootstocks against soil based pathogens and nematode. Reactions of improvement lines derived from local gene resources for rootstock improvement to heavy metal stress which is one of the abiotic stresses were determined. While determining the resistance against Pb stress, commercially used eggplant rootstocks are compared. In this study 4 eggplant cultivars (S. melongena: Burdur Bucak, Mardin Kızıltepe, Artvin Hopa and Kemer whose resistance potential against salt and drought stresses had been previously revealed and 6 rootstocks of wild eggplant species or hybrids (AGR-703, Doyran, Hawk, Hikyaku, Köksal-F1 and Vista-306 were tested against Pb stress. Eggplant seedlings were applied to 0, 150 and 300 ppm Pb solutions (Pb(NO32 during 4-5 true leaf stage. 20 days after the stress application wet and dry weight of green parts and roots, height of the body part and leaf areas were measured. Pb tolerance of Köksal F1 and AGR703 rootstocks were higher than other commercial rootstocks. Mardin Kızıltepe and Burdur Merkez genotypes which have high tolerances against abiotic stress gave lower values with respect to Artvin Hopa and Kemer which are sensitive genotypes and many other rootstocks while comparing the reduction ratios of stress signs such as shoot fresh weight and shoot length according to control under Pb stress.

Multiplicação in vitro do porta-enxerto de Prunus spp. 'Carelli' In vitro multiplication of Prunus spp. rootstocks 'Carelli'

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Paulo de Tarso Teixeira

2004-08-01

Full Text Available No Brasil, a falta de porta-enxertos para as Prunáceas, principalmente de origem clonal, tem incentivado a seleção de novas variedades e o uso de técnicas de cultura in vitro para a propagação. Neste sentido, o objetivo deste trabalho foi avaliar o potencial de multiplicação in vitro do porta-enxerto 'Carelli' sob efeito de diferentes concentrações da citocinina 6-benzilaminopurina (BAP. Segmentos nodais com 0,5 cm de comprimento foram inoculados em meio de cultura de Lepoivre, suplementado com 0,0; 0,5; 1,0; 2,0 e 4,0 mg.L-1 BAP. Estes segmentos nodais são oriundos de plântulas preestabelecidas in vitro, após duas subculturas em meio de cultura de Lepoivre, suplementado com 0,5 mg.L-1 de BAP. As avaliações para número de brotos por explante e altura média das brotações foram realizadas após 21 dias de cultura in vitro. Os resultados mostraram que os tratamentos com BAP não apresentaram diferenças significativas entre si. A taxa média de multiplicação foi de 3,3 a 3,4 brotos por explante. O tratamento sem adição de BAP não apresentou a formação de brotações axilares, mas resultou em brotos com maior altura média (16,2 mm. O uso de BAP afetou significativamente a altura das brotações, e o acréscimo nas suas concentrações reduziu o comprimento das mesmas. Concentrações de BAP superiores a 1,0 mg.L-1de BAP reduziram o comprimento das brotações e promoveram hiperidricidade. O uso de 0,5 mg.L-1 de BAP promoveu a formação de 3,3 brotos por explante com 11,0 mm de altura média, em condições adequadas para o enraizamento.In Brazil the lack of well adapted rootstocks in the Peach industry, mainly of clonal origin, forces the selection of new varieties and the use of tissue culture techniques for the mass clonal propagation. In the present work it was evaluated the in vitro multiplication potential of "Carelli" rootstock in response to different levels of BA. Nodal segments (0.5 cm length were inoculated in

A Research on the affinity coefficients of Red Globe grape variety with 140 R, 41 B rootstocks

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Gargin Seckin

2014-01-01

Full Text Available This research has been performed in order to evaluate four different affinity coefficients with formulas, with the purpose to determine achievement ratios related to the omega grafting applied onto the 41 B, 140R rootstock of the Red Globe grape variety which is commercially important grape variety in Lakes Region of Turkey. The study was done in Egirdir Fruit Research Station in Isparta city of Turkey. When the affinity values were statistically analyzed according to rootstocks and year, combinations was significantly evaluated and by evaluating 2012 and 2013 year's data consecutively, hopeful combinations were determined. It has been determined that 2013 years affinity coefficients and 140 R rootstock combination were slightly better than 2012 year and 41B combination. It has been determined that evaluating only with the formulations is not sufficient to get an exact result by the determination of a good affinity. Therefore it is needed to continue studies in future for a long time growing. The results which were evaluated in this study and next years' studies results must be evaluated together when a stable affinity occurs, a final result and suggestion can be made about combinations. Rootstock proposals regarding to the varieties and regions can be made paying special attention to these features will be beneficial for successful viticulture in the future.

Breeding graft-compatible Douglas-fir rootstocks (Pseudotsuga menziesii (Mirb.) Franco).

Science.gov (United States)

D.L. Copes

1999-01-01

A study encompassing 24 years was conducted to determine if a breeding program could produce highly graft-compatible rootstocks. Twenty-seven trees of apparent high graft compatibility were selected and crossed to produce 226 control-pollinated families. Seedlings were grown, field planted, and grafted with test scions. Graft unions from field tests were evaluated...

Detection of drought tolerant genes within seedling apple rootstocks in Syria

Science.gov (United States)

This investigation was conducted to detect the drought tolerant genes (four genes) within seedling apple rootstocks derived from five apple genotypes, including Syrian apple cultivars. The results showed that the gene MdPepPro (a cyclophilin) was found in all studied genotypes and their progenies e...

Naming Disney's Dwarfs.

Science.gov (United States)

Sidwell, Robert T.

1980-01-01

Discusses Disney's version of the folkloric dwarfs in his production of "Snow White" and weighs the Disney rendition of the dwarf figure against the corpus of traits and behaviors pertaining to dwarfs in traditional folklore. Concludes that Disney's dwarfs are "anthropologically true." (HOD)

Bottle gourd rootstock-grafting promotes photosynthesis by regulating the stomata and non-stomata performances in leaves of watermelon seedlings under NaCl stress.

Science.gov (United States)

Yang, Yanjuan; Yu, Li; Wang, Liping; Guo, Shirong

2015-08-15

Previously, we found that the amelioration of photosynthetic capacity by bottle gourd (Lagenaria siceraria Standl.) rootstock in watermelon seedlings (Citrullus lanatus [Thunb.] Mansf.) with salt treatment might be closely related to the enzymes in Calvin cycle such as ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) (Yang et al., 2012). We confirmed this and showed more details in this study that improved photosynthesis of watermelon plants by bottle gourd rootstock was associated with the decreased stomata resistance and the increased photochemical activity and photosynthetic metabolism with or without 100mM NaCl stress for 3 days. The analysis of gas exchange parameters showed that self-grafted plants suffered serious non-stomatal limitation to photosynthesis under salt stress while rootstock-grafted plants were mainly affected by stomata limitation in stress conditions. Further, results showed that NaCl stress markedly reduced the chlorophyll content, damaged the structure of photosynthetic apparatus, and inhibited photochemical activity and CO2 assimilation in self-grafted plants. In contrast, rootstock-grafting increased the chlorophyll content, especially chlorophyll b, and minimized the harmful effects on photosystem II (PSII) reaction center and the thylakoids structure induced by NaCl stress. Furthermore, rootstock-grafting enhanced the content and activity of Rubisco and thus elevated carbon fixation in the leaves of watermelon scions under salt stress. The gene expressions of enzymes related to ribulose-1,5-bisphosphate (RuBP) regeneration were also up-regulated by rootstock and this probably guaranteed the sufficient supply of RuBP for the operation of Calvin cycle in watermelon scions under salt stress. Thus, bottle gourd rootstock promoted photosynthesis by the activation of stomatal and non-stomatal abilities, especially the regulation of a variety of photosynthetic enzymes, including Rubisco in grafted watermelon plants under NaCl stress

Different adaptation strategies of two citrus scion/rootstock combinations in response to drought stress.

Science.gov (United States)

Dutra de Souza, Joadson; de Andrade Silva, Edson Mario; Coelho Filho, Mauricio Antônio; Morillon, Raphaël; Bonatto, Diego; Micheli, Fabienne; da Silva Gesteira, Abelmon

2017-01-01

Scion/rootstock interaction is important for plant development and for breeding programs. In this context, polyploid rootstocks presented several advantages, mainly in relation to biotic and abiotic stresses. Here we analyzed the response to drought of two different scion/rootstock combinations presenting different polyploidy: the diploid (2x) and autotetraploid (4x) Rangpur lime (Citrus limonia, Osbeck) rootstocks grafted with 2x Valencia Delta sweet orange (Citrus sinensis) scions, named V/2xRL and V/4xRL, respectively. Based on previous gene expression data, we developed an interactomic approach to identify proteins involved in V/2xRL and V/4xRL response to drought. A main interactomic network containing 3,830 nodes and 97,652 edges was built from V/2xRL and V/4xRL data. Exclusive proteins of the V/2xRL and V/4xRL networks (2,056 and 1,001, respectively), as well as common to both networks (773) were identified. Functional clusters were obtained and two models of drought stress response for the V/2xRL and V/4xRL genotypes were designed. Even if the V/2xRL plant implement some tolerance mechanisms, the global plant response to drought was rapid and quickly exhaustive resulting in a general tendency to dehydration avoidance, which presented some advantage in short and strong drought stress conditions, but which, in long terms, does not allow the plant survival. At the contrary, the V/4xRL plants presented a response which strong impacts on development but that present some advantages in case of prolonged drought. Finally, some specific proteins, which presented high centrality on interactomic analysis were identified as good candidates for subsequent functional analysis of citrus genes related to drought response, as well as be good markers of one or another physiological mechanism implemented by the plants.

Evaluation of PAL activity, Phenolic and Flavonoid Contents in Three Pistachio (Pistacia vera L. Cultivars Grafted onto Three Different Rootstocks

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N. Nadernejad

2013-08-01

Full Text Available Phenylalanine ammonia lyase (PAL is a biochemical marker of the environmental stress and plays a pivotal role in phenolic synthesis. The lower ROS level and oxidative damage was observed in grafted plants and the rootstocks have a profound influence on the biochemical composition, especially phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars ("Ahmadaghaii", "Ohadi" and "Kallehghuchi" on three rootstocks (Mutica, Ahli, Sarakhs. PAL activity, phenolic compounds, flavonoid and anthocyanin contents in leaves, flowers and fruits were measured toward the selection of the most suitable and compatible rootstock/scion resistant to environmental stresses. The results showed that PAL activity was different among the cultivars and organs. A positive correlation was observed between PAL activity and phenolic compounds in the leaves and flowers of Mutica- Ahmadaghaii, suggesting that it is more resistant than the others to environmental stresses. PAL activity and total phenolics in fruits of pistachio suffered a decrease when the maturation processes began. The hulls of the pistachio fruits contained high levels of phenolic compounds especially in Mutica-Ahmadaghaii suggesting its function as a protective layer and a defense chemical against ultraviolet radiation and pathogen. Our results indicated the presence of a number of bioactive compounds in kernels with the highest amount belonging to Mutica- Ahmadaghaii, and therefore it is concluded that pistachio rootstocks may affect the antioxidant compounds in kernels.

BIOFERTILIZATION WITH RHIZOBACTERIA AND A CONSORTIUM OF ARBUSCULAR MYCORRHIZAL FUNGI IN CITRUS ROOTSTOCKS

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Roberto Gregorio Chiquito-Contreras

2012-11-01

Full Text Available Biofertilization of plants with rhizobacteria and vesicular arbuscular mycorrhizae (mycorrhizal consortium, potentially promotes plant growth and health, and reduces the use of agrochemicals. The effect of individual and combined biofertilization with three strains of rhizobacteria and the mycorrhizal consortium (MTZ-1 was evaluated under nursery conditions on the growth of rootstocks of Citrus volkameriana and Rangpur lime grafted with Tahiti lime. Plants were inoculated individually and combined with the rhizobacteria strains FCA-8, FCA-56 and FCA-60 of Pseudomonas putida, and with MTZ-1; 50 % fertilization also was applied (18-46-00 N-P-K and compared with controls that received nursery management and 100 % fertilization. A split-plot experimental design with five replications per treatment was established. Individual and combined biofertilization with the three strains of bacteria and MTZ-1 positively promoted the growth of C. volkameriana, and Rangpur lime grafted with Tahiti lime, similar to the control with 100 % fertilization. The nutrient content of Tahiti lime leaves was similar to the control for both rootstocks. The presence of rhizobacterial and mycorrhizal populations in the combined biofertilization treatments demonstrated a positive synergism in the colonization of rootstock roots. Results demonstrate the potential of the three strains of P. putida and the MTZ-1 mycorrhizal consortium on the promotion of plant growth and assimilation of nutrients.

Temperatures and luminosities of white dwarfs in dwarf novae

International Nuclear Information System (INIS)

Smak, J.

1984-01-01

Far ultraviolet radiation observed in dwarf novae at minimum can only be attributed to their white dwarfs. In three systems white dwarfs are detected directly through their eclipses. These data are used to determine the effective temperatures and luminosities of white dwarfs. The resulting temperatures range from about logT e = 4.1 to about 4.9, with typical values of about 4.5. The luminosities range from about logL 1 = 31.0 to about 33.5 and show correlation with the average accretion rates. Radiation from white dwarfs is likely to be the source of excitation of the emission lines from disks. It is also argued that the heating by the white dwarf can significantly modify the structure of the innermost parts of the disk and, particularly, inhibit the incidence of thermal instability in that region. 26 refs., 2 figs., 1 tab. (author)

PERFORMANCE OF ‘TUXPAN VALENCIA’ SWEET ORANGE GRAFTED ONTO 14 ROOTSTOCKS IN NORTHERN BAHIA, BRAZIL

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NATIANA DE OLIVEIRA FRANÇA

Full Text Available ABSTRACT In the State of Bahia, Brazil, the citrus industry is located on the north coast with the prevalence of the combination ‘Pera’ sweet orange on ‘Rangpur’ lime. Scion-rootstock diversification may contribute to the increase of yield and the extension of harvest season, as long as to decrease the risk associated to abiotic and biotic stresses. Therefore, the performance of ‘Tuxpan Valencia’ sweet orange grafted onto 14 rootstocks was evaluated in Rio Real – BA. Planting was performed in 2006 under rainfed cultivation on cohesive ultisol and tree spacing of 6.0 m x 4.0 m. Tree size, yield and fruit quality were evaluated in the period of 2010-2014, in addition to tree survival at nine years old and drought tolerance in the field based on leaf wilting. In the evaluated conditions, ‘Sunki Tropical’ and ‘Sunki Maravilha’ mandarins led to the highest scion canopy volume. The highest accumulated yield in five harvests was recorded on ‘Santa Cruz Rangpur’ lime, ‘Volkamer’ lemon, ‘Riverside’ and ‘Indio’ citrandarins, ‘Sunki Tropical’ mandarin and the hybrid TSKC x (LCR x TR – 001. ‘Riverside’ and TSKFL x CTSW – 049 induced higher yield efficiency on the canopy. The rootstocks did not influence the tree survival nine years after planting except for lower survival of TSKFL x CTSW – 049. Drought tolerance was not affected either. Regarding to the fruit quality of ‘Tuxpan Valencia’, the rootstocks influenced the juice content, soluble solids and technological index with the citrandarins, ‘Santa Cruz Rangpur’ lime, ‘Volkamer’ lemon and ‘Sunki Tropical’ mandarin presenting higher performance in general.

The effects of citrus rootstocks on Valencia Late and Rhode Red ...

African Journals Online (AJOL)

STORAGESEVER

2008-12-17

Dec 17, 2008 ... However, all cultivars mean were within the range of optimal limits except Zn. The rootstock had ... optimize fertilization programs. ... Leaf samples were decontaminated by washing detergent solution, tap water and rinsing with distilled water. Then, samples were dried at. 70°C until constant weight and ...

Keberhasilan sambungan pada beberapa jenis batang atas dan famili batang bawah kakao (Theobroma cocoa L.. (Grafting performance of some scion clones and root-stock family on cocoa (Theobroma cocoa L.

Directory of Open Access Journals (Sweden)

Indah Anita Sari

2012-08-01

Full Text Available Differences in performance of grafting seedling were estimated from effect of using the root-stock and scion clones. This research aimed to study the differences of performance of some root-stock and scion clones on grafting seedling. The study used split plot design. First factor was root-stock consisted of ICS 60, Sca 6, Sca 12 and KW 165 and the second factor were 12 scions clones consisted of ICCRI 01, ICCRI 04, ICCRI 05, DR 2, Sulawesi 1, Sulawesi 2, KW 516, KW 514, KW 617, KW 570, KEE 2, and KW 604. There were three replication in each treatment and each replication consisted of 15 samples. Viability, lingkage diameter, ratio of root-stock and scion, hight of shoot, number of leaves and shoot were observed. The study showed that differences of root-stock just affected viability, lingkage diameter, and high of shoot. Scion clones factor affected to all of the characters. Their interaction caused the differences of all characters except of the number of shoot. Root-stock Sca 6 showed the lowest viability and number of the shoot, however root-stock KW 165 and ICS 60 showed the best performance to all parameters. The cluster analysis was done based on growth parameters and viability on lingkage distance of 15. There were three clusters; cluster 1 (KW 570, cluster 2 (ICCRI 04, ICCRI 05, Sulawesi 1, Sulawesi 2, KW 514, KW 165 and cluster 3 (ICCRI 01, DR 2, KW 516, KW 617, KW 604. Correlation analysis showed that main factor which affected the high viability root-stock diameter and diameter ratio of root-stock and scion were used.

An unsuccessful search for brown dwarf companions to white dwarf stars

Science.gov (United States)

Shipman, Harry L.

1986-01-01

The results of a survey to detect excess infrared emission from white dwarf stars which would be attributable to a low mass companion are reviewed. Neither a simple comparison of spectroscopically identified white dwarf stars with the IRAS Point Source Catalog nor the coadding of IRAS survey data resulted in a detection of a brown dwarf. The seven nearest stars where the most stringent limits to the presence of a brown dwarf were obtained are listed, and an effort to detect brown dwarfs in the solar neighborhood is discussed.

The effects of citrus rootstocks on Valencia Late and Rhode Red ...

African Journals Online (AJOL)

For N, K, Mg, Mn and Cu, Carrizo citrange has the highest means while Troyer and sour orange have the highest concentrations for P and. Fe, and Ca, Zn and Na, respectively. We recommend utilizations of Carrizo and Troyer citrange rootstocks for eastern Mediterranean region citrus production as they had higher ability to ...

White dwarf radii and boundary-layer constraints in three dwarf novae

International Nuclear Information System (INIS)

Wood, J.H.

1990-01-01

The structure of the boundary layer between the accretion disc and white dwarf in three quiescent dwarf novae is explored with high signal-to-noise eclipse light curves obtained by phase folding 12-20 eclipses. Models of the eclipse shapes of various white dwarf/boundary layer configurations that might be at the centres of the accretion discs are calculated and compared with observations of the eclipses in Z Cha, OY Car and HT Cas. Possible models for the central objects are found to be a white dwarf with or without its lower hemisphere occulted by the disc, or a white dwarf with an optically thick boundary layer significantly extended in latitude up and down its sides. The most likely of these models for each system is an unocculted white dwarf with no boundary layer contributing significantly to the optical flux, or a white dwarf totally covered by an optically thick boundary layer. (author)

SATELLITE DWARF GALAXIES IN A HIERARCHICAL UNIVERSE: THE PREVALENCE OF DWARF-DWARF MAJOR MERGERS

OpenAIRE

Deason, A; Wetzel, A; Garrison-Kimmel, S

2014-01-01

Mergers are a common phenomenon in hierarchical structure formation, especially for massive galaxies and clusters, but their importance for dwarf galaxies in the Local Group remains poorly understood. We investigate the frequency of major mergers between dwarf galaxies in the Local Group using the ELVIS suite of cosmological zoom-in dissipationless simulations of Milky Way- and M31-like host halos. We find that ~10% of satellite dwarf galaxies with M_star > 10^6 M_sun that are within the host...

The effect of mulching on water consumption, yield and some parameters in apple orchards grafted onto dwarf rootstock

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Cenk KÜÇÜKYUMUK

2013-06-01

Full Text Available This study was conducted to determine the effect of different mulch materials on plant water consumption, yield, fruit quality, vegetative growth, and weed control and soil temperature of Braeburn apple variety grafted onto M9 rootstock in Eğirdir Fruit Growing Research Station in 2010-2011. The experimental design was a randomized block design with three replications. Three different treatments were determined as two different mulch materials (white fabric, black plastic covering and control (without any mulching. Irrigation water was applied by using drip irrigation system in 7 days intervals. Amount of irrigation water to be applied in the each irrigation was determined as water amount needed for raising the soil moisture to the field capacity in 0-60 cm soil depth. As a result, substantial water saving has been provided from both of the mulch materials (%< 22-28 in comparison with the control treatment. The yield results showed statistically significant difference (p<0.05 among the treatments only in the second year. The highest red colour density value, which is an important criterion in apple marketing, was obtained from mulching with white fabric for both years. It was determined that mulch applications with these two materials were positive effects on vegetative growth and they were very effective on weed control. Soil temperature measured in the treatment used white fabric was found 1-2°C lower in comparison with control treatment, while it was found 3-4°C lower in comparison with the black plastic covering.

Propagule pressure, habitat conditions and clonal integration influence the establishment and growth of an invasive clonal plant, Alternanthera philoxeroides

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Wen-Hua eYou

2016-05-01

Full Text Available Many notorious invasive plants are clonal, spreading mainly by vegetative propagules. Propagule pressure (the number of propagules may affect the establishment, growth and thus invasion success of these clonal plants, and such effects may also depend on habitat conditions. To understand how propagule pressure, habitat conditions and clonal integration affect the establishment and growth of the invasive clonal plants, an 8-week greenhouse with an invasive clonal plant, Alternanthera philoxeroides was conducted. High (five fragments or low (one fragment propagule pressure was established either in bare soil (open habitat or dense native vegetation of Jussiaea repens (vegetative habitat, with the stolon connections either severed from or connected to the relatively older ramets. High propagule pressure greatly increased the establishment and growth of A. philoxeroides, especially when it grew in vegetative habitats. Surprisingly, high propagule pressure significantly reduced the growth of individual plants of A. philoxeroides in open habitats, whereas it did not affect the individual growth in vegetative habitats. A shift in the intraspecific interaction on A. philoxeroides from competition in open habitats to facilitation in vegetative habitats may be the main reason. Moreover, clonal integration significantly improved the growth of A. philoxeroides only in open habitats, especially with low propagule pressure, whereas it had no effects on the growth and competitive ability of A. philoxeroides in vegetative habitats, suggesting that clonal integration may be of most important for A. philoxeroides to explore new open space and spread. These findings suggest that propagule pressure may be crucial for the invasion success of A. philoxeroides, and such an effect also depends on habitat conditions.

ClonEvol: clonal ordering and visualization in cancer sequencing.

Science.gov (United States)

Dang, H X; White, B S; Foltz, S M; Miller, C A; Luo, J; Fields, R C; Maher, C A

2017-12-01

Reconstruction of clonal evolution is critical for understanding tumor progression and implementing personalized therapies. This is often done by clustering somatic variants based on their cellular prevalence estimated via bulk tumor sequencing of multiple samples. The clusters, consisting of the clonal marker variants, are then ordered based on their estimated cellular prevalence to reconstruct clonal evolution trees, a process referred to as 'clonal ordering'. However, cellular prevalence estimate is confounded by statistical variability and errors in sequencing/data analysis, and therefore inhibits accurate reconstruction of the clonal evolution. This problem is further complicated by intra- and inter-tumor heterogeneity. Furthermore, the field lacks a comprehensive visualization tool to facilitate the interpretation of complex clonal relationships. To address these challenges we developed ClonEvol, a unified software tool for clonal ordering, visualization, and interpretation. ClonEvol uses a bootstrap resampling technique to estimate the cellular fraction of the clones and probabilistically models the clonal ordering constraints to account for statistical variability. The bootstrapping allows identification of the sample founding- and sub-clones, thus enabling interpretation of clonal seeding. ClonEvol automates the generation of multiple widely used visualizations for reconstructing and interpreting clonal evolution. ClonEvol outperformed three of the state of the art tools (LICHeE, Canopy and PhyloWGS) for clonal evolution inference, showing more robust error tolerance and producing more accurate trees in a simulation. Building upon multiple recent publications that utilized ClonEvol to study metastasis and drug resistance in solid cancers, here we show that ClonEvol rediscovered relapsed subclones in two published acute myeloid leukemia patients. Furthermore, we demonstrated that through noninvasive monitoring ClonEvol recapitulated the emerging subclones

Performance of 'Okitsu' Satsuma Mandarin on nine rootstocks

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Zuleide Hissano Tazima

2013-12-01

Full Text Available Mandarins have become increasingly valued as citrus fruits for the fresh market due to the easy peeling, attractive flavor, and health and nutritional properties. Plant growth and yield, and characteristics of fruits of 'Okitsu' Satsuma mandarin (Citrus unshiu Marc. trees grafted on nine rootstocks were evaluated in Londrina, northern Paraná, Brazil. The rootstocks were: 'Rangpur' lime (Citrus limonia Osb.; 'Cleopatra' (Citrus reshni hort. ex Tanaka and 'Sunki' mandarins (Citrus sunki hort. ex Tanaka; 'C-13' [Citrus sinensis × Poncirus trifoliata (L. Raf.] and 'Carrizo' citranges [C. sinensis × P. trifoliata (L. Raf.]; 'Volkamer' lemon (Citrus volkameriana V. Ten. & Pasq.; trifoliate orange [P. trifoliata (L. Raf.; 'Caipira DAC' sweet orange [C. sinensis (L. Osb.] and 'Swingle' citrumelo [Citrus paradisi Macfad. cv. Duncan × P. trifoliata (L. Raf.]. The highest plant growth was for the trees on 'Cleopatra' mandarin and 'Caipira DAC' sweet orange. In contrast, the smallest size was for the trees on 'Volkamer' lemon and trifoliate orange. The largest difference between the trunk diameter below and above the grafting point was induced by 'Swingle' citrumelo. Trees of 'Okitsu' Satsuma mandarin on 'Swingle' citrumelo presented the highest yield, while 'C-13', 'Carrizo', 'Sunki', and 'Swingle' induced the largest fruit masses. With regard to fruit characteristics, 'Carrizo' and trifoliate orange induced the best ratio and juice content. Based on theoretical values, 'Rangpur' lime and 'Volkamer' lemon induced the lowest yields

Different adaptation strategies of two citrus scion/rootstock combinations in response to drought stress.

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Joadson Dutra de Souza

Full Text Available Scion/rootstock interaction is important for plant development and for breeding programs. In this context, polyploid rootstocks presented several advantages, mainly in relation to biotic and abiotic stresses. Here we analyzed the response to drought of two different scion/rootstock combinations presenting different polyploidy: the diploid (2x and autotetraploid (4x Rangpur lime (Citrus limonia, Osbeck rootstocks grafted with 2x Valencia Delta sweet orange (Citrus sinensis scions, named V/2xRL and V/4xRL, respectively. Based on previous gene expression data, we developed an interactomic approach to identify proteins involved in V/2xRL and V/4xRL response to drought. A main interactomic network containing 3,830 nodes and 97,652 edges was built from V/2xRL and V/4xRL data. Exclusive proteins of the V/2xRL and V/4xRL networks (2,056 and 1,001, respectively, as well as common to both networks (773 were identified. Functional clusters were obtained and two models of drought stress response for the V/2xRL and V/4xRL genotypes were designed. Even if the V/2xRL plant implement some tolerance mechanisms, the global plant response to drought was rapid and quickly exhaustive resulting in a general tendency to dehydration avoidance, which presented some advantage in short and strong drought stress conditions, but which, in long terms, does not allow the plant survival. At the contrary, the V/4xRL plants presented a response which strong impacts on development but that present some advantages in case of prolonged drought. Finally, some specific proteins, which presented high centrality on interactomic analysis were identified as good candidates for subsequent functional analysis of citrus genes related to drought response, as well as be good markers of one or another physiological mechanism implemented by the plants.

Effect of low doses of gamma irradiation on in vitro growth of some apple rootstock and varieties

International Nuclear Information System (INIS)

Charbaji, T.; Ayyoubi, Z.; Sarakbi, G.

2007-04-01

Three apple rootstocks (MM106, MM109 and Bizree) and 2 local varieties (Sucary and Sakarji) were collected from the field. Internode explants of the above rootstocks varieties were micropropagated on MS and modified MS media. Shoot growth of MM106 and MM109 rootstocks and Sucary variety increased significantly in modified MS. Similar results were observed on leaf number of MM109 and Bizree rootstocks and the 2 varieties in the same medium. Three rooting media (1, 2 and 3) were used by transferring microcuttings, to auxin free 50% strength MS (1), 50% strength MS with 1 mg.l - 1 IAA and 2 mg.l - 1 IBA (2) and 50% strength MS with 2 mg.l - 1 IAA and 4 mg.l - 1 NAA (3). All plants cultured on rotting media were irradiated with different doses of gamma irradiation (0, 2, 5, 7 and 10 Gy). During the initial 5 days of the rooting treatment, the cultures were incubated in darkness. During this period, the root initials are formed, and then the cultures were moved to the light. The highest rooting percentages in MM109, MM106, Sucary and Sakarji were obtained at 7 Gy with medium no 3 (92.5%, 87.5%, 93% and 90% respectively). Also, a combination of 7 Gy and medium no 3. When 5 Gy was combined with medium no 2 the root number of Sucary variety was increased, a similar result was observed in Sakarji variety when 5 and 7 Gy were integrated with both media no 1 and no 3.(author)

White dwarf heating and the ultraviolet flux in dwarf novae

International Nuclear Information System (INIS)

Pringle, J.E.

1988-01-01

An investigation is made of the heating of the outer layers of the white dwarf which is likely to occur during a dwarf nova outburst. It is shown that the decline in IUE flux, observed during quiescent intervals in the dwarf novae VW Hydri and WX Hydri, may be due to the outer layers cooling off once the heat source is removed. The calculations here assume uniformity of the heat source over the white dwarf surface. This is unlikely to be realized from disc accretion, and we discuss that further calculations are required. (author)

Searching for benchmark systems containing ultra-cool dwarfs and white dwarfs

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Pinfield D.J.

2013-04-01

Full Text Available We have used the 2MASS all-sky survey and WISE to look for ultracool dwarfs that are part of multiple systems containing main sequence stars. We cross-matched L dwarf candidates from the surveys with Hipparcos and Gliese stars, finding two new systems. We consider the binary fraction for L dwarfs and main sequence stars, and further assess possible unresolved multiplicity within the full companion sample. This analysis shows that some of the L dwarfs in this sample might actually be unresolved binaries themselves. We have also identified a sample of common proper motion systems in which a main sequence star has a white dwarf as wide companion. These systems can help explore key issues in star evolution theory, as the initial-final mass relationship of white dwarfs, or the chromospheric activity-age relationship for stars still in the main sequence. Spectroscopy for 50 white dwarf candidates, selected from the SuperCOSMOS Science Archive, was obtained. We have also observed 6 of the main sequence star companions, and have estimated their effective temperatures, rotational and microturbulent velocities and metallicities.

Evaluation of pal activity, phenolic and flavonoid contents in three pistachio ( Pistacia vera L. ) cultivars grafted onto three different rootstocks

OpenAIRE

Nadernejad, N.; Ahmadimoghadam, A.; Hossyinifard, J.; Poorseyedi, S.

2013-01-01

Phenylalanine ammonia lyase (PAL) is a biochemical marker of the environmental stress and plays a pivotal role in phenolic synthesis. The lower ROS level and oxidative damage was observed in grafted plants and the rootstocks have a profound influence on the biochemical composition, especially phenolic compounds. Regarding the importance of the effect rootstocks have on scion in pistachio trees, this study was carried out to assess and compare three pistachio cultivars ("Ahmadaghaii", "Ohadi" ...

Recent advances in understanding clonal haematopoiesis in aplastic anaemia.

Science.gov (United States)

Stanley, Natasha; Olson, Timothy S; Babushok, Daria V

2017-05-01

Acquired aplastic anaemia (AA) is an immune-mediated bone marrow failure disorder inextricably linked to clonal haematopoiesis. The majority of AA patients have somatic mutations and/or structural chromosomal abnormalities detected as early as at diagnosis. In contrast to other conditions linked to clonal haematopoiesis, the clonal signature of AA reflects its immune pathophysiology. The most common alterations are clonal expansions of cells lacking glycophosphotidylinositol-anchored proteins, loss of human leucocyte antigen alleles, and mutations in BCOR/BCORL1, ASXL1 and DNMT3A. Here, we present the current knowledge of clonal haematopoiesis in AA as it relates to aging, inherited bone marrow failure, and the grey-zone overlap of AA and myelodysplastic syndrome (MDS). We conclude by discussing the significance of clonal haematopoiesis both for improved diagnosis of AA, as well as for a more precise, personalized approach to prognostication of outcomes and therapy choices. © 2017 John Wiley & Sons Ltd.

Clonality evaluation in human tissues

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Villamizar-Rivera, Nicolás

2015-07-01

Full Text Available Malignant proliferations are usually clonal. While most times the biological potential can be established through routine pathologic and clinical examinations, some cases are difficult to classify. Moreover, in some situations there are dominant clones whose analysis is important, such as in autoimmune diseases and immunodeficiency. This paper presents in an understandable way the main techniques for the study of clonality, namely: evaluation of gene rearrangements of antigen receptor, and evaluation of human antigen receptor gene.

Cacao genetic resources research at the USDA-ARS Tropical Agriculture Research Station, Mayaguez, Puerto Rico

Science.gov (United States)

The current USDA ARS Tropical Agriculture Research Station’s (TARS) cacao (Theobroma cacao L.) collection in Mayaguez, Puerto Rico, consists of 262 clonally propagated accessions. Each accession is represented by six individual trees grafted onto a common ‘Amelonado’ seedling rootstock and planted ...

Resistance to phytophthora and graft compatibility with persian walnut among seedlings of chinese wingnut from different sources

Science.gov (United States)

Seedlings from seven open-pollinated selections of Chinese wingnut (Pterocarya stenoptera) (WN) representing collections of the USDA-ARS National Clonal Germplasm Repository at Davis CA and the University of California at Davis were evaluated as rootstocks for resistance to Phytophthora cinnamomi an...

Insights in Anaphylaxis and Clonal Mast Cell Disorders

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David González-de-Olano

2017-07-01

Full Text Available The prevalence of anaphylaxis among patients with clonal mast cell disorders (MCD is clearly higher comparing to the general population. Due to a lower frequency of symptoms outside of acute episodes, clonal MCD in the absence of skin lesions might sometimes be difficult to identify which may lead to underdiagnosis, and anaphylaxis is commonly the presenting symptom in these patients. Although the release of mast cell (MC mediators upon MC activation might present with a wide variety of symptoms, particular clinical features typically characterize MC mediator release episodes in patients with clonal MCD without skin involvement. Final diagnosis requires a bone marrow study, and it is recommended that this should be done in reference centers. In this article, we address the main triggers for anaphylaxis, risk factors, clinical presentation, diagnosis, and management of patients with MC activation syndromes (MCASs, with special emphasis on clonal MCAS [systemic mastocytosis and mono(clonal MC activations syndromes].

FIRST DIRECT EVIDENCE THAT BARIUM DWARFS HAVE WHITE DWARF COMPANIONS

International Nuclear Information System (INIS)

Gray, R. O.; McGahee, C. E.; Griffin, R. E. M.; Corbally, C. J.

2011-01-01

Barium II (Ba) stars are chemically peculiar F-, G-, and K-type objects that show enhanced abundances of s-process elements. Since s-process nucleosynthesis is unlikely to take place in stars prior to the advanced asymptotic giant branch (AGB) stage, the prevailing hypothesis is that each present Ba star was contaminated by an AGB companion which is now a white dwarf (WD). Unless the initial mass ratio of such a binary was fairly close to unity, the receiving star is thus at least as likely to be a dwarf as a giant. So although most known Ba stars appear to be giants, the hypothesis requires that Ba dwarfs be comparably plentiful and moreover that they should all have WD companions. However, despite dedicated searches with the IUE satellite, no WD companions have been directly detected to date among the classical Ba dwarfs, even though some 90% of those stars are spectroscopic binaries, so the contamination hypothesis is therefore presently in some jeopardy. In this paper, we analyze recent deep, near-UV and far-UV Galaxy Evolution Explorer (GALEX) exposures of four of the brightest of the class (HD 2454, 15360, 26367, and 221531), together with archived GALEX data for two newly recognized Ba dwarfs: HD 34654 and HD 114520 (which also prove to be spectroscopic binaries). The GALEX observations of the Ba dwarfs as a group show a significant far-UV excess compared to a control sample of normal F-type dwarfs. We suggest that this ensemble far-UV excess constitutes the first direct evidence that Ba dwarfs have WD companions.

Effects of rootstocks and irrigation levels on grape quality of Vitis ...

African Journals Online (AJOL)

Moreover, T1 or T2 treatments caused an increase in TA, TP, AA, TSS, total sugar content, ash, and CIRG index values of grape samples in comparison to that of vines irrigated with T3, T4 and T5 levels. Grape quality response to irrigation levels was altered by rootstocks and quality of grapes harvested from vines grafted on ...

White Dwarf Stars

OpenAIRE

Kepler, S. O.; Romero, Alejandra Daniela; Pelisoli, Ingrid; Ourique, Gustavo

2017-01-01

White dwarf stars are the final stage of most stars, born single or in multiple systems. We discuss the identification, magnetic fields, and mass distribution for white dwarfs detected from spectra obtained by the Sloan Digital Sky Survey up to Data Release 13 in 2016, which lead to the increase in the number of spectroscopically identified white dwarf stars from 5000 to 39000. This number includes only white dwarf stars with log g >= 6.5 stars, i.e., excluding the Extremely Low Mass white dw...

Radiation of dwarf novae

International Nuclear Information System (INIS)

Bruch, A.

1987-01-01

The nature of dwarf novae with their components white dwarf star, cool star, accretion disk, boundary layer and hot spot is investigated. It is shown that very different physical states and processes occur in the components of dwarf novae. Spectroscopical and photometrical observations are carried out. For better understanding the radiation portions of the single dwarf novae components are separated from the total electromagnetic spectrum recieved from the dwarf novae. The model assumptions are compared with the observations and verified

The genetics of tolerance to tristeza disease in citrus rootstocks

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Rita Bordignon

2004-01-01

Full Text Available Controlled pollinations between four elite citrus rootstocks, Citrus limonia - 'Limeira' rangpur lime (Cravo, C. sunki - 'Sunki' mandarin (Sunki, C. aurantium - 'São Paulo' sour orange (Azeda and Poncirus trifoliata - 'Davis A' trifoliate orange (Trifoliata, resulted in 1614 nucelar and 1938 hybrid plants identified by the isozyme loci Pgi-1, Pgm-1, Got-1, Got-2, Aps-1, Me-1, Prxa-1 and or by the morphological markers broadness of leaf petiole wing or trifoliolate leaves. Tolerance to the citrus tristeza virus (CTV was evaluated under nursery and field conditions for several years by the reaction of Valencia orange infected with a severe strain of CTV and grafted onto the hybrids and nucellar clones. Genetic analyses indicated that tolerance was controlled by at least two loci designated here as Az and t interacting in dominant-recessive epistasis. Genotypes Az__ __ __ and __ __ tt were tolerant while azaz T__ was intolerant. The intolerant Azeda was azaz TT, the tolerant rootstocks Sunki and Cravo were Azaz tt and the Trifoliata was Azaz TT. The different degrees of intolerance seen in some hybrids may reflect the inability of segregating modifiers from parental clones to overcome the epistatic interaction that controls the major tolerance reaction.

The effects of different salt concentrations on growth and chlorophyll content of some pumpkin rootstocks

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Köksal AYDİNŞAKİR

2015-12-01

Full Text Available This study was conducted to determine the effects of different salinity levels, (0.7, 4.0, 8.0, 12.0, 16.0 dS m-1 on some physiological parameters of Obez F1, Ferro F1, RS841 F1, which are used as rootstocks in watermelon cultivation. Salty irrigation water was obtained through mixing of NaCl and CaCl2 salt into tap water. When the plants were at the 3-4 leaf stage, different salinity levels were applied. Plants were harvested during the phase of florescence. The study was carried out using split plots in randomized complete block design while rootstocks are main plot, salinity levels are sub-plot with three replications. While the salinity level was increasing, the physiological parameters decreased in each three rootstocks. While the plant height changed between 14.4-107.1 cm, the plant leaf area varied between 152.0-2182.7 cm2. Chlorophyll-a, chlorophyll-b and total carotenoid values decreased as the salinity level increased. Excluding the maximum value obtained from control plot, the highest chlorophyll-a, chlorophyll-b, and total carotenoid values were obtained in Obez variety under 4.0 dS m-1 application with 14.8 mg l-1, 12.8 mg l-1 and 0.28 mg g-1 fw, respectively.

Using gamma irradiation for the improvement of MM106 and omara apple Malus domestica Borkh rootstocks to sodium chloride tolerance in Vitro

International Nuclear Information System (INIS)

Aljibouri, A.A.M.; Abdel-Hussen, M.A.; Salman, M.A.

2010-01-01

In vitro plant lets of MM106 and Omara apple rootstocks were irradiated with gamma ray doses (0, 5, 10, 15, 20, 25, 30, and 35 Gray). Shoot tips of irradiated plant lets with incremental doses were in vitro cultured on MS medium supplemented with different NaCl concentrations to study the effect of gamma rays and NaCl salt on shoot number, shoot length and rooting percentage. Results revealed that gamma rays treatment improved significantly the parameters investigated for both types of rootstocks, especially the doses of 15 and 20 Gy for MM106 and 25 Gy for Omara. On the other hand, salinity caused a significant reduction in all parameters measured with different trend between both types of rootstocks. The results also showed significant interaction between gamma rays doses and NaCl concentrations.

WHITE DWARF/M DWARF BINARIES AS SINGLE DEGENERATE PROGENITORS OF TYPE Ia SUPERNOVAE

International Nuclear Information System (INIS)

Wheeler, J. Craig

2012-01-01

Limits on the companions of white dwarfs in the single-degenerate scenario for the origin of Type Ia supernovae (SNe Ia) have gotten increasingly tight, yet igniting a nearly Chandrasekhar mass C/O white dwarf from a condition of near hydrostatic equilibrium provides compelling agreement with observed spectral evolution. The only type of non-degenerate stars that survive the tight limits, M V ∼> 8.4 on the SN Ia in SNR 0509-67.5 and M V ∼> 9.5 in the remnant of SN 1572, are M dwarfs. While M dwarfs are observed in cataclysmic variables, they have special properties that have not been considered in most work on the progenitors of SNe Ia: they have small but finite magnetic fields and they flare frequently. These properties are explored in the context of SN Ia progenitors. White dwarf/M dwarf pairs may be sufficiently plentiful to provide, in principle, an adequate rate of explosions even with slow orbital evolution due to magnetic braking or gravitational radiation. Even modest magnetic fields on the white dwarf and M dwarf will yield adequate torques to lock the two stars together, resulting in a slowly rotating white dwarf, with the magnetic poles pointing at one another in the orbital plane. The mass loss will be channeled by a 'magnetic bottle' connecting the two stars, landing on a concentrated polar area on the white dwarf. This enhances the effective rate of accretion compared to spherical accretion. Luminosity from accretion and hydrogen burning on the surface of the white dwarf may induce self-excited mass transfer. The combined effects of self-excited mass loss, polar accretion, and magnetic inhibition of mixing of accretion layers give possible means to beat the 'nova limit' and grow the white dwarf to the Chandrasekhar mass even at rather moderate mass accretion rates.

Responses of grapevine rootstocks to drought through altered root system architecture and root transcriptomic regulations.

Science.gov (United States)

Yıldırım, Kubilay; Yağcı, Adem; Sucu, Seda; Tunç, Sümeyye

2018-06-01

Roots are the major interface between the plant and various stress factors in the soil environment. Alteration of root system architecture (RSA) (root length, spread, number and length of lateral roots) in response to environmental changes is known to be an important strategy for plant adaptation and productivity. In light of ongoing climate changes and global warming predictions, the breeding of drought-tolerant grapevine cultivars is becoming a crucial factor for developing a sustainable viticulture. Root-trait modeling of grapevine rootstock for drought stress scenarios, together with high-throughput phenotyping and genotyping techniques, may provide a valuable background for breeding studies in viticulture. Here, tree grafted grapevine rootstocks (110R, 5BB and 41B) having differential RSA regulations and drought tolerance were investigated to define their drought dependent root characteristics. Root area, root length, ramification and number of root tips reduced less in 110R grafted grapevines compared to 5BB and 41B grafted ones during drought treatment. Root relative water content as well as total carbohydrate and nitrogen content were found to be much higher in the roots of 110R than it was in the roots of other rootstocks under drought. Microarray-based root transcriptome profiling was also conducted on the roots of these rootstocks to identify their gene regulation network behind drought-dependent RSA alterations. Transcriptome analysis revealed totally 2795, 1196 and 1612 differentially expressed transcripts at the severe drought for the roots of 110R, 5BB and 41B, respectively. According to this transcriptomic data, effective root elongation and enlargement performance of 110R were suggested to depend on three transcriptomic regulations. First one is the drought-dependent induction in sugar and protein transporters genes (SWEET and NRT1/PTR) in the roots of 110R to facilitate carbohydrate and nitrogen accumulation. In the roots of the same rootstock

Propagação por enxertia de atemoia 'Thompson' sobre espécies de Rollinia 'Thompson' atemoya grafting onto Rollinia rootstocks

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Luis Felipe Paes de Almeida

2010-06-01

Full Text Available Este estudo teve por finalidade avaliar o índice de sobrevivência do enxerto de atemoia 'Thompson' sobre dois porta-enxertos. O delineamento experimental foi em blocos casualizados, em esquema fatorial 2 x 2, dois porta-enxertos [araticum-de-terra-fria (Rollinia sp. e biribá (Rollinia mucosa] e dois métodos de enxertia (topo em fenda lateral e topo à inglesa simples, em 6 blocos, 4 tratamentos e 5 plantas por parcela, totalizando 120 plantas. Para as condições locais, verificou-se que a atemoia pode ser propagada com sucesso via enxertia, usando o porta-enxerto araticum-de-terra-fria, com diferença significativa em relação ao biribá. O melhor método de enxertia para araticum-de-terra-fria foi o inglês simples, com índice de sobrevivência do enxerto de 90%. Observou-se baixo índice de sobrevivência do enxerto, utilizando-se de ambos os métodos de enxertia para o porta-enxerto biribá.This study aimed to evaluate the survival rate of atemoya 'Thompson' on two rootstocks.The experimental design used was in randomized blocks with factorial scheme 2 x 2 consisting of 6 blocks, 4 treatments and 5 replicates per parcel totaling 120 plants. Two grafting methods (side cleft graft and whip graft and two rootstocks [araticum-de-terra-fria (Rollinia sp. and biriba (Rollinia mucosa] were evaluated for propagation of 'Thompson' atemoya. Scion survival rate was evaluated and analyzed by Tukey test, with 5% of significance level. Atemoya tree under local conditions can be propagated successfully by grafting using araticum-de-terra-fria rootstock. Whip graft was the best grafting method for araticum-de-terra-fria rootstock with 90% survival. Both grafting methods for biriba rootstock resulted in low scion survival rate.

FORMATION OF ULTRA-COMPACT BLUE DWARF GALAXIES AND THEIR EVOLUTION INTO NUCLEATED DWARFS

International Nuclear Information System (INIS)

Bekki, Kenji

2015-01-01

We propose that there is an evolutionary link between ultra-compact blue dwarf galaxies (UCBDs) with active star formation and nucleated dwarfs based on the results of numerical simulations of dwarf–dwarf merging. We consider the observational fact that low-mass dwarfs can be very gas-rich, and thereby investigate the dynamical and chemical evolution of very gas-rich, dissipative dwarf–dwarf mergers. We find that the remnants of dwarf–dwarf mergers can be dominated by new stellar populations formed from the triggered starbursts and consequently can have blue colors and higher metallicities (Z ∼ [0.2–1]Z ⊙ ). We also find that the remnants of these mergers can have rather high mass densities (10 4 M ⊙ pc −3 ) within the central 10 pc and small half-light radii (40−100 pc). The radial stellar structures of some merger remnants are similar to those of nucleated dwarfs. Star formation can continue in nuclear gas disks (R < 100 pc) surrounding stellar galactic nuclei (SGNs) so that the SGNs can finally have multiple stellar populations with different ages and metallicities. These very compact blue remnants can be identified as UCBDs soon after merging and as nucleated dwarfs after the young stars fade. We discuss these results in the context of the origins of metal-rich ultra-compact dwarfs and SGNs

FORMATION OF ULTRA-COMPACT BLUE DWARF GALAXIES AND THEIR EVOLUTION INTO NUCLEATED DWARFS

Energy Technology Data Exchange (ETDEWEB)

Bekki, Kenji [ICRAR, M468, The University of Western Australia 35 Stirling Highway, Crawley Western Australia, 6009 (Australia)

2015-10-10

We propose that there is an evolutionary link between ultra-compact blue dwarf galaxies (UCBDs) with active star formation and nucleated dwarfs based on the results of numerical simulations of dwarf–dwarf merging. We consider the observational fact that low-mass dwarfs can be very gas-rich, and thereby investigate the dynamical and chemical evolution of very gas-rich, dissipative dwarf–dwarf mergers. We find that the remnants of dwarf–dwarf mergers can be dominated by new stellar populations formed from the triggered starbursts and consequently can have blue colors and higher metallicities (Z ∼ [0.2–1]Z{sub ⊙}). We also find that the remnants of these mergers can have rather high mass densities (10{sup 4} M{sub ⊙} pc{sup −3}) within the central 10 pc and small half-light radii (40−100 pc). The radial stellar structures of some merger remnants are similar to those of nucleated dwarfs. Star formation can continue in nuclear gas disks (R < 100 pc) surrounding stellar galactic nuclei (SGNs) so that the SGNs can finally have multiple stellar populations with different ages and metallicities. These very compact blue remnants can be identified as UCBDs soon after merging and as nucleated dwarfs after the young stars fade. We discuss these results in the context of the origins of metal-rich ultra-compact dwarfs and SGNs.

The Evaluation of the Effect of Multiwall Carbon Nano Tube (MWCNT) on In Vitro Proliferation and Shoot Tip Necrosis of Pistachio Rootstock UCB-1 (Pistacia integrima × P. atlantica)

OpenAIRE

Shahrzad Aghasi Kermani; Hossein Hokmabadi; Marzieh Ghanbari Jahromi

2017-01-01

UCB-1 (Pistacia atlantica × P. integrima) is a commercial rootstock for pistachio in some pistachio plantations across the world. This rootstock is very new in Iran and recently, it has been used commercially in some plantations due to its high growth. Propagation of this rootstock by tissue culture results in many limitations such as shoot tip necrosis (STN) and a low proliferation rate. Therefore, any process that leads to improve the proliferation rate and feature will be used in commercia...

New Light on Dark Stars Red Dwarfs, Low-Mass Stars, Brown Dwarfs

CERN Document Server

Reid, I. Neill

2005-01-01

There has been very considerable progress in research into low-mass stars, brown dwarfs and extrasolar planets during the past few years, particularly since the fist edtion of this book was published in 2000. In this new edtion the authors present a comprehensive review of both the astrophysical nature of individual red dwarf and brown dwarf stars and their collective statistical properties as an important Galactic stellar population. Chapters dealing with the observational properies of low-mass dwarfs, the stellar mass function and extrasolar planets have been completely revised. Other chapters have been significantly revised and updated as appropriate, including important new material on observational techniques, stellar acivity, the Galactic halo and field star surveys. The authors detail the many discoveries of new brown dwarfs and extrasolar planets made since publication of the first edition of the book and provide a state-of-the-art review of our current knowledge of very low-mass stars, brown dwarfs a...

Aging in a long-lived clonal tree.

Directory of Open Access Journals (Sweden)

Dilara Ally

2010-08-01

Full Text Available From bacteria to multicellular animals, most organisms exhibit declines in survivorship or reproductive performance with increasing age ("senescence". Evidence for senescence in clonal plants, however, is scant. During asexual growth, we expect that somatic mutations, which negatively impact sexual fitness, should accumulate and contribute to senescence, especially among long-lived clonal plants. We tested whether older clones of Populus tremuloides (trembling aspen from natural stands in British Columbia exhibited significantly reduced reproductive performance. Coupling molecular-based estimates of clone age with male fertility data, we observed a significant decline in the average number of viable pollen grains per catkin per ramet with increasing clone age in trembling aspen. We found that mutations reduced relative male fertility in clonal aspen populations by about 5.8 x 10(-5 to 1.6 x 10(-3 per year, leading to an 8% reduction in the number of viable pollen grains, on average, among the clones studied. The probability that an aspen lineage ultimately goes extinct rises as its male sexual fitness declines, suggesting that even long-lived clonal organisms are vulnerable to senescence.

Phenotypic variation among trees in a population of a Pistacia atlantica X P. integerrima cross sold as UCB-1 rootstock for grafting P. vera (pistachio) cultivars

Science.gov (United States)

UCB-1 is widely used in California as a pistachio rootstock because of its Verticillium resistance, salt and cold tolerance, and vigor. It can grow in most locations in California. However, significant variation exists in the phenotypic performance of trees grafted to seedling UCB-1 rootstocks. In J...

Evaluation of Two Biochemical Markers for Salt Stress in Three Pistachio Rootstocks Inoculated with Arbuscular Mycorrhiza (Glomus mosseae

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Shamshiri M.H.

2014-03-01

Full Text Available The possible involvement of the methylglyoxal and proline accumulation in leaves and roots of three pistachio rootstocks, cv. Sarakha, Abareqi and Bane baghi, pre-inoculated with arbuscular mycorrhizal fungus (Glomus mosseae in response to salt stress was studied during a greenhouse experiment in 2013. Six months old pistachio seedlings were exposed to four salinity levels of irrigation water (EC of 0.5 as control, 5, 10 and 15 dS m-1 for 70 days. Methylglyoxal and proline of the roots and leaves were increased by increasing salt stress. The highest concentrations of proline in leaves and roots were recorded in Abareqi rootstock while the lowest concentration was observed in Sarakhs. In general, a negative relationship was obtained between proline and methylglyoxal concentrations in both tissues especially at two highest levels of salinity. A very strong relationship between salinity and measured biochemical markers were found. The level of both biomarkers were reduced in both tissues and in all rootstocks as the effect of mycorrhizal symbiosis. Root colonization percentage was declined as the effect of salinity in Abareqi and Bane baghi and not in Sarakhs.

Distinguishing CDM dwarfs from SIDM dwarfs in baryonic simulations

Science.gov (United States)

Strickland, Emily; Fitts, Alex B.; Boylan-Kolchin, Michael

2017-06-01

Dwarf galaxies in the nearby Universe are the most dark-matter-dominated systems known. They are therefore natural probes of the nature of dark matter, which remains unknown. Our collaboration has performed several high-resolution cosmological zoom-in simulations of isolated dwarf galaxies. We simulate each galaxy in standard cold dark matter (ΛCDM) as well as self-interacting dark matter (SIDM, with a cross section of σ/m ~ 1 cm2/g), both with and without baryons, in order to identify distinguishing characteristics between the two. The simulations are run using GIZMO, a meshless-finite-mass hydrodynamical code, and are part of the Feedback in Realistic Environments (FIRE) project. By analyzing both the global properties and inner structure of the dwarfs in varying dark matter prescriptions, we provide a side-by-side comparison of isolated, dark-matter-dominated galaxies at the mass scale where differences in the two models of dark matter are thought to be the most obvious. We find that the edge of classical dwarfs and ultra-faint dwarfs (at stellar masses of ~105 solar masses) provides the clearest window for distinguishing between the two theories. At these low masses, our SIDM galaxies have a cored inner density profile, while their CDM counterparts have “cuspy” centers. The SIDM versions of each galaxy also have measurably lower stellar velocity dispersions than their CDM counterparts. Future observations of ultra faint dwarfs with JWST and 30-m telescopes will be able to discern whether such alternate theories of dark matter are viable.

In Vitro Propagarion and Cryopreservation of Important Grape Cultivars (Vitis Vinifera L. and Rootstocks

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F. CELEBI TOPRAK

2014-06-01

Full Text Available Grape (Vitis vinifera L. is among the most important species that is cultivated almost all around the world. There are over one thousand varieties that are grown for raisin, fresh consumption and wine making purposes. The grape germplasm resources are generally maintained as whole plants under field conditions. The traditional way of germplasm preservation is very risky due to natural uncertainties. In vitro technologies can help producing healthy propagation materials free from viroids, viruses, bacteria, phytoplasmas, fungi, and nematodes. When combined with cryopreservation technologies in vitro preservation systems can allow safe protection and propagation of valuable Vitis genetic resources. In this study, 12 commercial cultivar and two rootstock materials were tested for the applicability of long term preservation by in vitro clonal propagation and cryopreservation techniques. Axillary shoot tips collected from newly emerging shoots were placed in Magenda boxes containing 30 g/l sucrose on MS medium and cultured in a growth chamber adjusted to 16 h ligth/25o C and 8 h dark/17o C. All grape genotypes tested responded well to this application and produced healthy root and shoots. Shoot explants from these in vitro stocks were subcultured in every three months for one year. Apical dome explants excised from in vitro grape plants were stored in liquid nitrogen for cryopreservation. Genotypes varied in their responses to cryopservation treatment. Five genotypes showed shoot or callus formation. Regenerated shoots continued to grow and produced normal shoots and roots, but no plants could be developed from calli. Flow cytometry analysis of regenerants from continuous subculture and cryopreservation did not show any chromosome number abnormalities. In vitro micropropagation is an excellent choice for a long-term conservation of grape germplasm, which allows access to actively growing plant materials without seasonal restriction. Such cultures are

THE BROWN DWARF KINEMATICS PROJECT (BDKP). III. PARALLAXES FOR 70 ULTRACOOL DWARFS

International Nuclear Information System (INIS)

Faherty, Jacqueline K.; Shara, Michael M.; Cruz, Kelle L.; Burgasser, Adam J.; Walter, Frederick M.; Van der Bliek, Nicole; West, Andrew A.; Vrba, Frederick J.; Anglada-Escudé, Guillem

2012-01-01

We report parallax measurements for 70 ultracool dwarfs (UCDs) including 11 late-M, 32 L, and 27 T dwarfs. In this sample, 14 M and L dwarfs exhibit low surface gravity features, 6 are close binary systems, and 2 are metal-poor subdwarfs. We combined our new measurements with 114 previously published UCD parallaxes and optical-mid-IR photometry to examine trends in spectral-type/absolute magnitude, and color-color diagrams. We report new polynomial relations between spectral type and M JHK . Including resolved L/T transition binaries in the relations, we find no reason to differentiate between a 'bright' (unresolved binary) and a 'faint' (single source) sample across the L/T boundary. Isolating early T dwarfs, we find that the brightening of T0-T4 sources is prominent in M J where there is a [1.2-1.4] mag difference. A similar yet dampened brightening of [0.3-0.5] mag happens at M H and a plateau or dimming of [–0.2 to –0.3] mag is seen in M K . Comparison with evolutionary models that vary gravity, metallicity, and cloud thickness verifies that for L into T dwarfs, decreasing cloud thickness reproduces brown dwarf near-IR color-magnitude diagrams. However we find that a near constant temperature of 1200 ±100 K along a narrow spectral subtype of T0-T4 is required to account for the brightening and color-magnitude diagram of the L-dwarf/T-dwarf transition. There is a significant population of both L and T dwarfs which are red or potentially 'ultra-cloudy' compared to the models, many of which are known to be young indicating a correlation between enhanced photospheric dust and youth. For the low surface gravity or young companion L dwarfs we find that 8 out of 10 are at least [0.2-1.0] mag underluminous in M JH and/or M K compared to equivalent spectral type objects. We speculate that this is a consequence of increased dust opacity and conclude that low surface gravity L dwarfs require a completely new spectral-type/absolute magnitude polynomial for analysis.

THE BROWN DWARF KINEMATICS PROJECT (BDKP). III. PARALLAXES FOR 70 ULTRACOOL DWARFS

Energy Technology Data Exchange (ETDEWEB)

Faherty, Jacqueline K.; Shara, Michael M.; Cruz, Kelle L. [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034 (United States); Burgasser, Adam J. [Center of Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, CA 92093 (United States); Walter, Frederick M. [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Van der Bliek, Nicole [CTIO/National Optical Astronomy Observatory (Chile); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Ave Boston, MA 02215 (United States); Vrba, Frederick J. [US Naval Observatory, Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002 (United States); Anglada-Escude, Guillem, E-mail: jfaherty@amnh.org [Department of Terrestrial Magnetism, Carnegie Institution of Washington 5241 Broad Branch Road, NW, Washington, DC 20015 (United States)

2012-06-10

We report parallax measurements for 70 ultracool dwarfs (UCDs) including 11 late-M, 32 L, and 27 T dwarfs. In this sample, 14 M and L dwarfs exhibit low surface gravity features, 6 are close binary systems, and 2 are metal-poor subdwarfs. We combined our new measurements with 114 previously published UCD parallaxes and optical-mid-IR photometry to examine trends in spectral-type/absolute magnitude, and color-color diagrams. We report new polynomial relations between spectral type and M{sub JHK}. Including resolved L/T transition binaries in the relations, we find no reason to differentiate between a 'bright' (unresolved binary) and a 'faint' (single source) sample across the L/T boundary. Isolating early T dwarfs, we find that the brightening of T0-T4 sources is prominent in M{sub J} where there is a [1.2-1.4] mag difference. A similar yet dampened brightening of [0.3-0.5] mag happens at M{sub H} and a plateau or dimming of [-0.2 to -0.3] mag is seen in M{sub K} . Comparison with evolutionary models that vary gravity, metallicity, and cloud thickness verifies that for L into T dwarfs, decreasing cloud thickness reproduces brown dwarf near-IR color-magnitude diagrams. However we find that a near constant temperature of 1200 {+-}100 K along a narrow spectral subtype of T0-T4 is required to account for the brightening and color-magnitude diagram of the L-dwarf/T-dwarf transition. There is a significant population of both L and T dwarfs which are red or potentially 'ultra-cloudy' compared to the models, many of which are known to be young indicating a correlation between enhanced photospheric dust and youth. For the low surface gravity or young companion L dwarfs we find that 8 out of 10 are at least [0.2-1.0] mag underluminous in M{sub JH} and/or M{sub K} compared to equivalent spectral type objects. We speculate that this is a consequence of increased dust opacity and conclude that low surface gravity L dwarfs require a completely new

Clonal hematopoiesis in acquired aplastic anemia.

Science.gov (United States)

Ogawa, Seishi

2016-07-21

Clonal hematopoiesis (CH) in aplastic anemia (AA) has been closely linked to the evolution of late clonal disorders, including paroxysmal nocturnal hemoglobinuria and myelodysplastic syndromes (MDS)/acute myeloid leukemia (AML), which are common complications after successful immunosuppressive therapy (IST). With the advent of high-throughput sequencing of recent years, the molecular aspect of CH in AA has been clarified by comprehensive detection of somatic mutations that drive clonal evolution. Genetic abnormalities are found in ∼50% of patients with AA and, except for PIGA mutations and copy-neutral loss-of-heterozygosity, or uniparental disomy (UPD) in 6p (6pUPD), are most frequently represented by mutations involving genes commonly mutated in myeloid malignancies, including DNMT3A, ASXL1, and BCOR/BCORL1 Mutations exhibit distinct chronological profiles and clinical impacts. BCOR/BCORL1 and PIGA mutations tend to disappear or show stable clone size and predict a better response to IST and a significantly better clinical outcome compared with mutations in DNMT3A, ASXL1, and other genes, which are likely to increase their clone size, are associated with a faster progression to MDS/AML, and predict an unfavorable survival. High frequency of 6pUPD and overrepresentation of PIGA and BCOR/BCORL1 mutations are unique to AA, suggesting the role of autoimmunity in clonal selection. By contrast, DNMT3A and ASXL1 mutations, also commonly seen in CH in the general population, indicate a close link to CH in the aged bone marrow, in terms of the mechanism for selection. Detection and close monitoring of somatic mutations/evolution may help with prediction and diagnosis of clonal evolution of MDS/AML and better management of patients with AA. © 2016 by The American Society of Hematology.

Controlling the root and stem rot of cucumber, caused by Pythium aphanidermatum, using resistance cultivars and grafting onto the cucurbit rootstocks

Directory of Open Access Journals (Sweden)

Fatemeh Rostami

2015-02-01

Full Text Available Cucumber damping off caused by Pythium aphanidermatum is the most important root and stem rot that limits greenhouse cultivations. In this study, relative susceptibility of grafting commercial cucumber cultivars including Alpha, Caspian 340, Storm 5910, Shalim 616, Delta scar, Janette 810, Festibal C5, Royal, Negyn, Soltan and Fadia on two Cucurbita rootstocks were evaluated against P. aphanidermatum . Disease severity, survival and seedling growth were used for the evaluation. The results showed significant differences between the studied cultivars (p≤0.01. Caspian 340 and Alpha with 15.7% and 100% disease severity had more and less tolerant to P. aphanidermatum, respectively. Cucurbita maxima rootstock was more resistant than Cucurbita pepo to P. aphanidermatum. C. pepo had less compatibility with the cucumber and showed little resistance to the pathogen. The study revealed that grafting Caspian340 on the resistant cucurbit rootstock i.e. Cucurbita maxima could be used as disease control strategies in greenhouses.

Activity and Kinematics of White Dwarf-M Dwarf Binaries from the SUPERBLINK Proper Motion Survey

International Nuclear Information System (INIS)

Skinner, Julie N.; Morgan, Dylan P.; West, Andrew A.; Lépine, Sébastien; Thorstensen, John R.

2017-01-01

We present an activity and kinematic analysis of high proper motion white dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which are new identifications. To identify WD+dMs, we developed a UV–optical–IR color criterion and conducted a spectroscopic survey to confirm each candidate binary. For the newly identified systems, we fit the two components using model white dwarf spectra and M dwarf template spectra to determine physical parameters. We use H α chromospheric emission to examine the magnetic activity of the M dwarf in each system, and investigate how its activity is affected by the presence of a white dwarf companion. We find that the fraction of WD+dM binaries with active M dwarfs is significantly higher than their single M dwarf counterparts at early and mid-spectral types. We corroborate previous studies that find high activity fractions at both close and intermediate separations. At more distant separations, the binary fraction appears to approach the activity fraction for single M dwarfs. Using derived radial velocities and the proper motions, we calculate 3D space velocities for the WD+dMs in SUPERBLINK. For the entire SUPERBLINK WD+dMs, we find a large vertical velocity dispersion, indicating a dynamically hotter population compared to high proper motion samples of single M dwarfs. We compare the kinematics for systems with active M dwarfs and those with inactive M dwarfs, and find signatures of asymmetric drift in the inactive sample, indicating that they are drawn from an older population.

Activity and Kinematics of White Dwarf-M Dwarf Binaries from the SUPERBLINK Proper Motion Survey

Energy Technology Data Exchange (ETDEWEB)

Skinner, Julie N. [Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Morgan, Dylan P.; West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Lépine, Sébastien [Department of Physics and Astronomy, Georgia State University, 25 Park Place NE, Atlanta, GA, 30303 (United States); Thorstensen, John R., E-mail: jskinner@bu.edu [Department of Physics and Astronomy, 6127 Wilder Laboratory, Dartmouth College, Hanover, NH 03755 (United States)

2017-09-01

We present an activity and kinematic analysis of high proper motion white dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which are new identifications. To identify WD+dMs, we developed a UV–optical–IR color criterion and conducted a spectroscopic survey to confirm each candidate binary. For the newly identified systems, we fit the two components using model white dwarf spectra and M dwarf template spectra to determine physical parameters. We use H α chromospheric emission to examine the magnetic activity of the M dwarf in each system, and investigate how its activity is affected by the presence of a white dwarf companion. We find that the fraction of WD+dM binaries with active M dwarfs is significantly higher than their single M dwarf counterparts at early and mid-spectral types. We corroborate previous studies that find high activity fractions at both close and intermediate separations. At more distant separations, the binary fraction appears to approach the activity fraction for single M dwarfs. Using derived radial velocities and the proper motions, we calculate 3D space velocities for the WD+dMs in SUPERBLINK. For the entire SUPERBLINK WD+dMs, we find a large vertical velocity dispersion, indicating a dynamically hotter population compared to high proper motion samples of single M dwarfs. We compare the kinematics for systems with active M dwarfs and those with inactive M dwarfs, and find signatures of asymmetric drift in the inactive sample, indicating that they are drawn from an older population.

HR-MAS NMR metabolomics of 'Swingle' citrumelo rootstock genetically modified to overproduce proline.

Science.gov (United States)

de Oliveira, Caroline S; Carlos, Eduardo F; Vieira, Luiz G E; Lião, Luciano M; Alcantara, Glaucia B

2014-08-01

The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock. Copyright © 2014 John Wiley & Sons, Ltd.

Stomatal characteristics of Eucalyptus grandis clonal hybrids in ...

African Journals Online (AJOL)

This study describes the stomatal response occurring during water stress and subsequent recovery of three Eucalyptus grandis clonal hybrids. The aim was to investigate the degree to which stomatal conductance (gs) and stomatal density differ between the clonal hybrids across seasons and in response to water stress.

Activity and Kinematics of White Dwarf-M Dwarf Binaries from the SUPERBLINK Proper Motion Survey

Science.gov (United States)

Skinner, Julie N.; Morgan, Dylan P.; West, Andrew A.; Lépine, Sébastien; Thorstensen, John R.

2017-09-01

We present an activity and kinematic analysis of high proper motion white dwarf-M dwarf binaries (WD+dMs) found in the SUPERBLINK survey, 178 of which are new identifications. To identify WD+dMs, we developed a UV-optical-IR color criterion and conducted a spectroscopic survey to confirm each candidate binary. For the newly identified systems, we fit the two components using model white dwarf spectra and M dwarf template spectra to determine physical parameters. We use Hα chromospheric emission to examine the magnetic activity of the M dwarf in each system, and investigate how its activity is affected by the presence of a white dwarf companion. We find that the fraction of WD+dM binaries with active M dwarfs is significantly higher than their single M dwarf counterparts at early and mid-spectral types. We corroborate previous studies that find high activity fractions at both close and intermediate separations. At more distant separations, the binary fraction appears to approach the activity fraction for single M dwarfs. Using derived radial velocities and the proper motions, we calculate 3D space velocities for the WD+dMs in SUPERBLINK. For the entire SUPERBLINK WD+dMs, we find a large vertical velocity dispersion, indicating a dynamically hotter population compared to high proper motion samples of single M dwarfs. We compare the kinematics for systems with active M dwarfs and those with inactive M dwarfs, and find signatures of asymmetric drift in the inactive sample, indicating that they are drawn from an older population. Based on observations obtained at the MDM Observatory operated by Dartmouth College, Columbia University, The Ohio State University, and the University of Michigan.

Effects of Clonal Reproduction on Evolutionary Lag and Evolutionary Rescue.

Science.gov (United States)

Orive, Maria E; Barfield, Michael; Fernandez, Carlos; Holt, Robert D

2017-10-01

Evolutionary lag-the difference between mean and optimal phenotype in the current environment-is of keen interest in light of rapid environmental change. Many ecologically important organisms have life histories that include stage structure and both sexual and clonal reproduction, yet how stage structure and clonality interplay to govern a population's rate of evolution and evolutionary lag is unknown. Effects of clonal reproduction on mean phenotype partition into two portions: one that is phenotype dependent, and another that is genotype dependent. This partitioning is governed by the association between the nonadditive genetic plus random environmental component of phenotype of clonal offspring and their parents. While clonality slows phenotypic evolution toward an optimum, it can dramatically increase population survival after a sudden step change in optimal phenotype. Increased adult survival slows phenotypic evolution but facilitates population survival after a step change; this positive effect can, however, be lost given survival-fecundity trade-offs. Simulations indicate that the benefits of increased clonality under environmental change greatly depend on the nature of that change: increasing population persistence under a step change while decreasing population persistence under a continuous linear change requiring de novo variation. The impact of clonality on the probability of persistence for species in a changing world is thus inexorably linked to the temporal texture of the change they experience.

Rootstock and vineyard floor management influence on 'Cabernet Sauvignon' grape yeast assimilable nitrogen (YAN)

Science.gov (United States)

This is a preliminary study on the influence two rootstocks (110R, high vigor; 420A, low vigor) grafted to scion 'Cabernet Sauvignon' clone 8, and three vineyard floor management regimes (tilled resident vegetation – usual practice in California, and barley cover crops that were either mowed or till...

37 NEW T-TYPE BROWN DWARFS IN THE CANADA-FRANCE BROWN DWARFS SURVEY

International Nuclear Information System (INIS)

Albert, Loic; Artigau, Etienne; Delorme, Philippe; Reyle, Celine; Forveille, Thierry; Delfosse, Xavier; Willott, Chris J.

2011-01-01

The Canada-France Brown Dwarfs Survey is an i'- and z'-band survey realized with MegaCam at the Canada-France-Hawaii Telescope that covers a surface area of 780 deg 2 . Image analysis is now completed while J-band follow-up campaigns are ∼90% done. The survey identified about 70 T dwarf candidates, of which 43 now have near-infrared spectra obtained with NIRI and GNIRS at Gemini and ISAAC at the Very Large Telescope. Six of these were previously published and we present here the 37 new discoveries, all T dwarfs. They range from T0 to T8.5 with four being of type T7 or later. Both newly identified T8 dwarfs are possibly high log (g) massive brown dwarfs of thin disk age. One T4.5 dwarf shows signs of sub-metallicity. We present proper motions and near-infrared photometry, and discuss about the most peculiar/interesting objects in some details.

Mid-Infrared Observations of the White Dwarf Brown Dwarf Binary GD 1400

OpenAIRE

Farihi, J.; Zuckerman, B.; Becklin, E. E.

2005-01-01

Fluxes are measured for the DA white dwarf plus brown dwarf pair GD 1400 with the Infrared Array Camera on the {\\em Spitzer Space Telescope}. GD 1400 displays an infrared excess over the entire $3-8\\mu$m region consistent with the presence of a mid- to late-type L dwarf companion. A discussion is given regarding current knowledge of this unique system.

Stark Broadening and White Dwarfs

Directory of Open Access Journals (Sweden)

Dimitrijević Milan S.

2011-12-01

Full Text Available White dwarf and pre-white dwarfs are the best types of stars for the application of Stark broadening research results in astrophysics, since in the atmospheres of these stars physical conditions are very favorable for this line broadening mechanism - in hot hydrogen-deficient white dwarfs and pre-white dwarfs Teff = 75 000–180 000 K and log g = 5.5–8 [cgs]. Even for much cooler DA and DB white dwarfs with the typical effective temperatures 10 000-20 000 K, Stark broadening is usually the dominant broadening mechanism. In this review, Stark broadening in white dwarf spectra is considered, and the attention is drawn to the STARK-B database (http://stark-b.obspm.fr/, containing the parameters needed for analysis and synthesis of white dwarf spectra, as well as for the collective efforts to develop the Virtual Atomic and Molecular Data Center.

Proteomic study related to vascular connections in watermelon scions grafted onto bottle-gourd rootstock under different light intensities.

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Sowbiya Muneer

Full Text Available Although grafting is broadly used in the production of crops, no information is available about the proteins involved in vascular connections between rootstock and scion. Similarly, proteome changes under the light intensities widely used for grafted seedlings are of practical use. The objective of this study was to determine the proteome of vascular connections using watermelon (Citrullus vulgaris Schrad. 'Sambok Honey' and 'Speed' as the scion and bottle gourd (Lagenaria siceraria Stanld. 'RS Dongjanggun' as the rootstock grown under different light intensities (25, 50, 75 and 100 μmol m-2 s-1. Our proteomic analysis revealed 24 and 27 differentially expressed proteins in 'Sambok Honey' and 'Speed', respectively, under different light intensities. The identified proteins were largely involved in ion binding, amino acid metabolism, transcriptional regulation and defense response. The enhancement of ion-binding, transcriptional regulation, amino acid metabolism, and defense response proteins suggests a strengthening of the connection between the rootstock and scion under high light intensity. Indeed, the accumulation of key enzymes in the biological processes described above appears to play an important role in the vascular connections of grafted seedlings. Moreover, it appears that 100 μmol m-2 s-1 results in better protein expression responses in grafted seedlings.

Dwarf Mice and Aging.

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Masternak, Michal M; Darcy, Justin; Victoria, Berta; Bartke, Andrzej

2018-01-01

Dwarf mice have been studied for many decades, however, the focus of these studies shifted in 1996 when it was shown by Brown-Borg and her coworkers that Ames dwarf (Prop1 df ) mice are exceptionally long-lived. Since then, Snell dwarf (Pit1 dw ) and growth hormone receptor knockout (GHR-KO, a.k.a. Laron dwarf) mice were also shown to be exceptionally long-lived, presumably due to their growth hormone (GH)-deficiency or -resistance, respectively. What is of equal importance in these dwarf mice is their extended health span, that is, these animals have a longer period of life lived free of frailty and age-related diseases. This review article focuses on recent studies conducted in these dwarf mice, which concerned brown and white adipose tissue biology, microRNA (miRNA) profiling, as well as early-life dietary and hormonal interventions. Results of these studies identify novel mechanisms linking reduced GH action with extensions of both life span and health span. Copyright © 2017. Published by Elsevier Inc.

Effect of environmental stress on clonal structure of Eucypris virens (Crustacea, Ostracoda)

OpenAIRE

Martins M. J. F.; Vandekerkhove J.; Adolfsson S.; Rossetti G.; Namiotko T.; Jokela J.

2010-01-01

Environmental stress imposes strong natural selection on clonal populations, promoting evolutionary change in clonal structure. Environmental stress may also lead to reduction in population size, which together with clonal selection may reduce genotypic diversity of the local populations. We examined how clonal structure in wild-collected samples of two parthenogenetic populations of the freshwater ostracod Eucypris virens responded to hypersalinity and starvation, and the combination of the ...

Benchmarking Brown Dwarf Models With a Non-irradiated Transiting Brown Dwarf in Praesepe

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Beatty, Thomas; Marley, Mark; Line, Michael; Gizis, John

2018-05-01

We wish to use 9.4 hours of Spitzer time to observe two eclipses, one each at 3.6um and 4.5um, of the transiting brown dwarf AD 3116b. AD 3116b is a 54.2+/-4.3 MJ, 1.08+/-0.07 RJ object on a 1.98 day orbit about a 3200K M-dwarf. Uniquely, AD 3116 and its host star are both members of Praesepe, a 690+/-60 Myr old open cluster. AD 3116b is thus one of two transiting brown dwarfs for which we have a robust isochronal age that is not dependent upon brown dwarf evolutionary models, and the youngest brown dwarf for which this is the case. Importantly, the flux AD 3116b receives from its host star is only 0.7% of its predicted internal luminosity (Saumon & Marley 2008). This makes AD 3116b the first known transiting brown dwarf that simultaneously has a well-defined age, and that receives a negligible amount of external irradiation, and a unique laboratory to test radius and luminosity predictions from brown dwarf evolutionary models. Our goal is to measure the emission from the brown dwarf. AD 3116b should have large, 25 mmag, eclipse depths in the Spitzer bandpasses, and we expect to measure them with a precision of +/-0.50 mmag at 3.6um and +/-0.54 mmag at 4.5um. This will allow us to make measure AD 3116b?s internal effective temperature to +/-40K. We will also use the upcoming Gaia DR2 parallaxes to measure AD 3116b's absolute IRAC magnitudes and color, and hence determine the cloud properties of the atmosphere. As the only known brown dwarf with an independently measured mass, radius, and age, Spitzer measurements of AD 3116b's luminosity and clouds will provide a critical benchmark for brown dwarf observation and theory.

Mineral Content in Leaves of Tomato Plants Grafted on Solanum Rootstocks

OpenAIRE

松添, 直隆; 間, 浩美; 花田, 勝美; モハメド, アリ; 大久保, 敬; 藤枝, 國光

1995-01-01

Nutrient uptake of tomato plants cv. Momotaro grafted on Solanum sisymbriifoliulm, S. torvum and S. toxicarium which are resistant to soil-born disease were compared with tomato grafted on its own root, a tomato/tomato, scion/rootstock combination. Mineral content in leaves of tomato/S. sisymbriifoliulm was nearly equal to that of tomato/tomato. In leaves of tomato/S. torvum, nitrogen content was higher, and magnesium content was lower than those of tomato/tomato. Furthermore, phosphorus and ...

Sunki mandarin and Swingle citrumelo as rootstocks for rain-fed cultivation of late-season sweet orange selections in northern São Paulo state, Brazil

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Eduardo Augusto Girardi

2017-08-01

Full Text Available ABSTRACT In Brazilian regions affected by the citrus sudden death disease, sweet orange cultivation depends on the use of resistant rootstocks. Rangpur lime was mainly replaced by Swingle citrumelo and Sunki mandarin rootstocks, more drought-sensitive ones. The diversification of scion selections is also desirable aiming at the increasing demand for not from concentrate orange juice (NFC that requires high-quality fruits. In this work, we evaluated the performance of 6 selections of Valencia (IAC, Dom João, Late Burjasot IVIA 35-2, Rhode Red SRA 360, Temprana IVIA 25 and Campbell and Natal IAC sweet oranges grafted onto Swingle citrumelo and Sunki mandarin. The planting occurred in 2001 under rain-fed cultivation in Bebedouro, northern São Paulo state, Brazil. The outline was made through randomized blocks in a 7 × 2 factorial design (selections × rootstock, with 4 replications and 2 trees in unit. Both rootstocks performed well in the region. Sunki mandarin rootstock induced greater tree size and production per plant to the scion selections, 38 and 21%, respectively, plus higher precocity of production compared to Swingle citrumelo. The later determined a greater productive efficiency, as well as a greater percentage of juice in general, albeit with lower concentrations of soluble solids and acidity. Natal IAC, Valencia IAC and Rhode Red Valencia selections presented a higher accumulated production, on average, 218.6 kg∙plant−1 (2004 – 2008, and a higher productive efficiency (kg fruit∙m−3 of canopy due to their smaller tree size. All assessed selections produced fruits with high soluble solids content that were suitable for juice processing.

Marvel-ous Dwarfs: Results from Four Heroically Large Simulated Volumes of Dwarf Galaxies

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Munshi, Ferah; Brooks, Alyson; Weisz, Daniel; Bellovary, Jillian; Christensen, Charlotte

2018-01-01

We present results from high resolution, fully cosmological simulations of cosmic sheets that contain many dwarf galaxies. Together, they create the largest collection of simulated dwarf galaxies to date, with z=0 stellar masses comparable to the LMC or smaller. In total, we have simulated almost 100 luminous dwarf galaxies, forming a sample of simulated dwarfs which span a wide range of physical (stellar and halo mass) and evolutionary properties (merger history). We show how they can be calibrated against a wealth of observations of nearby galaxies including star formation histories, HI masses and kinematics, as well as stellar metallicities. We present preliminary results answering the following key questions: What is the slope of the stellar mass function at extremely low masses? Do halos with HI and no stars exist? What is the scatter in the stellar to halo mass relationship as a function of dwarf mass? What drives the scatter? With this large suite, we are beginning to statistically characterize dwarf galaxies and identify the types and numbers of outliers to expect.

From strange stars to strange dwarfs

International Nuclear Information System (INIS)

Glendenning, N.K.; Kettner, C.; Weber, F.

1995-01-01

We determine all possible equilibrium sequences of compact strange-matter stars with nuclear crusts, which range from massive strange stars to strange white dwarf endash like objects (strange dwarfs). The properties of such stars are compared with those of their nonstrange counterparts emdash neutron stars and ordinary white dwarfs. The main emphasis of this paper is on strange dwarfs, which we divide into two distinct categories. The first one consists of a core of strange matter enveloped within ordinary white dwarf matter. Such stars are hydrostatically stable with or without the strange core and are therefore referred to as open-quote open-quote trivial close-quote close-quote strange dwarfs. This is different for the second category which forms an entirely new class of dwarf stars that contain nuclear material up to 4x10 4 times denser than in ordinary white dwarfs of average mass, M∼0.6 M circle-dot , and still about 400 times denser than in the densest white dwarfs. The entire family of such dwarfs, denoted dense strange dwarfs, owes its hydrostatic stability to the strange core. A striking features of strange dwarfs is that the entire sequence from the maximum-mass strange star to the maximum-mass strange dwarf is stable to radial oscillations. The minimum-mass star is only conditionally stable, and the sequences on both sides are stable. Such a stable, continuous connection does not exist between ordinary white dwarfs and neutron stars, which are known to be separated by a broad range of unstable stars. We find an expansive range of very low mass (planetary-like) strange-matter stars (masses even below 10 -4 M circle-dot are possible) that arise as natural dark-matter candidates, which if abundant enough in our Galaxy, should be seen in the gravitational microlensing searches that are presently being performed. copyright 1995 The American Astronomical Society

Hubble Space Telescope Imaging and Spectral Analysis of Two Brown Dwarf Binaries at the L Dwarf/T Dwarf Transition

OpenAIRE

Burgasser, Adam J.; Gagliuffi, Daniella C. Bardalez; Gizis, John E.

2010-01-01

We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS show opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-lig...

Brown dwarfs as dark galactic halos

International Nuclear Information System (INIS)

Adams, F.C.; Walker, T.P.

1990-01-01

The possibility that the dark matter in galactic halos can consist of brown dwarf stars is considered. The radiative signature for such halos consisting solely of brown dwarfs is calculated, and the allowed range of brown dwarf masses, the initial mass function (IMF), the stellar properties, and the density distribution of the galactic halo are discussed. The prediction emission from the halo is compared with existing observations. It is found that, for any IMF of brown dwarfs below the deuterium burning limit, brown dwarf halos are consistent with observations. Brown dwarf halos cannot, however, explain the recently observed near-IR background. It is shown that future satellite missions will either detect brown dwarf halos or place tight constraints on the allowed range of the IMF. 30 refs

EFFECT OF MYCORRHIZAL INOCULANTS IN THE DEVELOPMENT OF MEXICAN LANDRACE AVOCADO ROOTSTOCKS

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Edgar Castro Alvarado

2013-12-01

Full Text Available The aim of this work was to assess the effect of two arbuscular mycorrhizal fungi (AMF inoculants in the development of avocado rootstocks. Seeds of Mexican landrace avocado (Persea americana Mill. var. drymifolia were used, with two commercial inoculants: T1 containing Glomus fasciculatum, G. constrictum, G. tortuosum, G. geosporum,and Acaulospora scrobiculata, and T2, containing G. mosseae and G. cubense.  The plants inoculated with AMF showed more rapid growth than the no inoculant control as measured by plant height (50% and 54%, stem diameter (35% and 36%, leaf number (48% and 37% and length (31% and 40%, and root fresh weight (85% and 59%; however, no significant differences were observed between T1 and T2. The chlorophyll concentration in the leaves from T1 was 16.4% and T2 was 19% higher than the control suggesting a higher photosynthetic capacity in T1 and T2. Finally the shoot/root ratio, as indicator of the potential development of plantations, was 79% and 50% higher in mycorrhizal plants than in the control. In conclusion both T1 and T2 inoculants improved growth rate and vigor of avocado nursery rootstocks producing higher quality plants.

Tetraploid Carrizo citrange rootstock (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) enhances natural chilling stress tolerance of common clementine (Citrus clementina Hort. ex Tan).

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Oustric, Julie; Morillon, Raphaël; Luro, François; Herbette, Stéphane; Lourkisti, Radia; Giannettini, Jean; Berti, Liliane; Santini, Jérémie

2017-07-01

Low temperatures can disturb the development, growth and geographic distribution of plants, particularly cold-sensitive plants in the Mediterranean area, where temperatures can reach seasonally low levels. In citrus crops, scion/rootstock combinations are used to improve fruit production and quality, and increase tolerance to biotic and abiotic stresses. In the last decade, several studies have shown that tetraploid citrus seedlings or rootstocks are more tolerant to abiotic stress than their respective diploid. The objective of this study was to test whether the use of tetraploid rootstocks can improve the chilling tolerance of the scion. We compared physiological and biochemical responses to low seasonal temperatures of common Clementine (Citrus sinensis Osb.×Poncirus trifoliata L. Raf.) grafted on diploid and tetraploid Carrizo citrange rootstocks, named C/2xCC and C/4xCC, respectively. During the coldest months, C/4xCC showed a smaller decrease in net photosynthesis (Pn), stomatal conductance (G s ), chlorophyll fluorescence (F v /F m ), and starch levels, and lower levels of malondialdehyde and electrolyte leakage than C/2xCC. Specific activities of catalase (CAT), ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) were higher in C/4xCC during the cold period, whereas chlorophyll, proline, ascorbate and hydrogen peroxide (H 2 O 2 ) levels and superoxide dismutase (SOD) activity did not vary significantly between C/4xCC and C/2xCC throughout the study period. Taken together, these results demonstrate that tetraploid Carrizo citrange rootstock improves the chilling tolerance of common clementine (scion) thanks to a part of the antioxidant system. Copyright © 2017. Published by Elsevier GmbH.

Testing Gravity Using Dwarf Stars

OpenAIRE

Sakstein, Jeremy

2015-01-01

Generic scalar-tensor theories of gravity predict deviations from Newtonian physics inside astrophysical bodies. In this paper, we point out that low mass stellar objects, red and brown dwarf stars, are excellent probes of these theories. We calculate two important and potentially observable quantities: the radius of brown dwarfs and the minimum mass for hydrogen burning in red dwarfs. The brown dwarf radius can differ significantly from the GR prediction and upcoming surveys that probe the m...

The galactic population of white dwarfs

International Nuclear Information System (INIS)

Napiwotzki, Ralf

2009-01-01

The contribution of white dwarfs of the different Galactic populations to the stellar content of our Galaxy is only poorly known. Some authors claim a vast population of halo white dwarfs, which would be in accordance with some investigations of the early phases of Galaxy formation claiming a top-heavy initial- mass- function. Here, I present a model of the population of white dwarfs in the Milky Way based on observations of the local white dwarf sample and a standard model of Galactic structure. This model will be used to estimate the space densities of thin disc, thick disc and halo white dwarfs and their contribution to the baryonic mass budget of the Milky Way. One result of this investigation is that white dwarfs of the halo population contribute a large fraction of the Galactic white dwarf number count, but they are not responsible for the lion's share of stellar mass in the Milky Way. Another important result is the substantial contribution of the - often neglected - population of thick disc white dwarfs. Misclassification of thick disc white dwarfs is responsible for overestimates of the halo population in previous investigations.

Dwarfs in ancient Egypt.

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Kozma, Chahira

2006-02-15

Ancient Egypt was one of the most advanced and productive civilizations in antiquity, spanning 3000 years before the "Christian" era. Ancient Egyptians built colossal temples and magnificent tombs to honor their gods and religious leaders. Their hieroglyphic language, system of organization, and recording of events give contemporary researchers insights into their daily activities. Based on the record left by their art, the ancient Egyptians documented the presence of dwarfs in almost every facet of life. Due to the hot dry climate and natural and artificial mummification, Egypt is a major source of information on achondroplasia in the old world. The remains of dwarfs are abundant and include complete and partial skeletons. Dwarfs were employed as personal attendants, animal tenders, jewelers, and entertainers. Several high-ranking dwarfs especially from the Old Kingdom (2700-2190 BCE) achieved important status and had lavish burial places close to the pyramids. Their costly tombs in the royal cemeteries and the inscriptions on their statutes indicate their high-ranking position in Egyptian society and their close relation to the king. Some of them were Seneb, Pereniankh, Khnumhotpe, and Djeder. There were at least two dwarf gods, Ptah and Bes. The god Ptah was associated with regeneration and rejuvenation. The god Bes was a protector of sexuality, childbirth, women, and children. He was a favored deity particularly during the Greco-Roman period. His temple was recently excavated in the Baharia oasis in the middle of Egypt. The burial sites and artistic sources provide glimpses of the positions of dwarfs in daily life in ancient Egypt. Dwarfs were accepted in ancient Egypt; their recorded daily activities suggest assimilation into daily life, and their disorder was not shown as a physical handicap. Wisdom writings and moral teachings in ancient Egypt commanded respect for dwarfs and other individuals with disabilities. Copyright (c) 2005 Wiley-Liss, Inc.

THE LINK BETWEEN PLANETARY SYSTEMS, DUSTY WHITE DWARFS, AND METAL-POLLUTED WHITE DWARFS

International Nuclear Information System (INIS)

Debes, John H.; Walsh, Kevin J.; Stark, Christopher

2012-01-01

It has long been suspected that metal-polluted white dwarfs (types DAZ, DBZ, and DZ) and white dwarfs with dusty disks possess planetary systems, but a specific physical mechanism by which planetesimals are perturbed close to a white dwarf has not yet been fully posited. In this paper, we demonstrate that mass loss from a central star during post-main-sequence evolution can sweep planetesimals into interior mean motion resonances with a single giant planet. These planetesimals are slowly removed through chaotic excursions of eccentricity that in time create radial orbits capable of tidally disrupting the planetesimal. Numerical N-body simulations of the solar system show that a sufficient number of planetesimals are perturbed to explain white dwarfs with both dust and metal pollution, provided other white dwarfs have more massive relic asteroid belts. Our scenario requires only one Jupiter-sized planet and a sufficient number of asteroids near its 2:1 interior mean motion resonance. Finally, we show that once a planetesimal is perturbed into a tidal crossing orbit, it will become disrupted after the first pass of the white dwarf, where a highly eccentric stream of debris forms the main reservoir for dust-producing collisions. These simulations, in concert with observations of white dwarfs, place interesting limits on the frequency of planetary systems around main-sequence stars, the frequency of planetesimal belts, and the probability that dust may obscure future terrestrial planet finding missions.

Search for brown dwarfs and late M dwarfs in the Hyades and the Pleiades

International Nuclear Information System (INIS)

Zuckerman, B.; Becklin, E.E.; Hawaii Univ., Honolulu)

1987-01-01

The J and K colors of 14 white dwarfs that are believed to be single stars and members of either the Hyades or Pleiades clusters or the Hyades supercluster were measured, and no indication of any excess 2.2 micron (K) emission above that expected from the white dwarf was found. Based on recently published theoretical cooling curves for brown dwarfs, the existence of any cool companion stars, with masses greater than approximately 0.03 solar mass within a radius of 6 arcsec of eight white dwarfs in the Hyades cluster and greater than approximately 0.015 solar mass toward the single white dwarf in the Pleiades, is ruled out. This latter limit, only 15 Jupiter masses, is probably the lowest that has yet been established for any star by purely infrared techniques. 21 references

Comparative drug susceptibility study of five clonal strains of Trichomonas vaginalis in vitro

Institute of Scientific and Technical Information of China (English)

Hemantkumar Somabhai Chaudhari; Prati Pal Singh

2011-01-01

Objective: To produce comparative data on a group of Trichomonas vaginalis clonal strains with varied drug responses using identical methods and materials. Methods: Five clonal strains of Trichomonas vaginalis were isolated from reference strain using agar plate technique. The variability of growth kinetic and susceptibility of clonal strain to metronidazole, tinidazole, satranidazole and nitazoxanide were observed in 96 well microtitre plate. Results: Among these clonal strains there was a good correlation between rates of growth with the relative susceptibility of the strains to drugs in vitro. Regarding metronidazole, tinidazole and satranidazole susceptibility, different degrees of susceptibility were determined. However, no difference in nitazoxanide susceptibility was found between the clonal strain tested and a reference strain.Conclusions: This is the first description of biological variability in clonal stock of Trichomonas vaginalis. Different degrees of drug susceptibility were determined among clonal strains tested. Further studies will be necessary to ascertain the importance of this variability in clinical infection.

A simple and cost effective liquid culture system for the micropropagation of two commercially important apple rootstocks.

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Mehta, Mohina; Ram, Raja; Bhattacharya, Amita

2014-07-01

The two commercially important apple rootstocks i.e., MM106 and B9 were micropropagated using a liquid culture system. Three different strengths of 0.8% agar solidified PGR free basal MS medium were first tested to optimize the culture media for both the rootstocks. Full strength medium (MS0) supported maximum in vitro growth, multiplication, rooting and survival under field conditions as opposed to quarter and half strength media. When three different volumes of liquid MS0 were tested, highest in vitro growth, multiplication, rooting and also survival under field conditions were achieved in 20 mL liquid MS0. The cost of one litre of liquid medium was also reduced by 8 times to Rs. 6.29 as compared to solid medium. The cost of 20 mL medium was further reduced to Rs. 0.125.

Phenolic and triterpenoid composition and inhibition of α-amylase of pistachio kernels (Pistacia vera L.) as affected by rootstock and irrigation treatment.

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Noguera-Artiaga, Luis; Pérez-López, David; Burgos-Hernández, Armando; Wojdyło, Aneta; Carbonell-Barrachina, Ángel A

2018-09-30

The current water scarcity forces farmers to adopt new irrigation strategies to save water without jeopardizing the fruit yield and quality. In this study, the influence of 3 regulated deficit irrigation (RDI) treatments and 3 rootstocks on the functional quality of pistachios were studied. The functional parameters studied included, polyphenols, triterpenoids, and inhibition of α-amylase. The results showed that P. terebinthus and P. atlantica rootstocks led to pistachio kernels with higher contents of polyphenols and triterpenoids (mainly betulinic acid with 111 and 102 µg g -1 , respectively) than pistachios obtained using P. integerrima rootstock (81 µg g -1 ). On the other hand, the use of moderate RDI (T1 treatment) increased the total content of polyphenols (∼10%), quercetin-O-galloyl-hexoside (∼15%), keampferol-3-O-glucoside (∼19%), and polymeric procyanidins (∼20%), as compared to the control trees, resulting in pistachios with a better functional profile, lower economic cost and with a lesser environmental impact. Copyright © 2018 Elsevier Ltd. All rights reserved.

Adjusting to global change through clonal growth and epigenetic variation

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Richard S Dodd

2016-07-01

Full Text Available The earth is experiencing major changes in global and regional climates and changes are predicted to accelerate in the future. Many species will be under considerable pressure to evolve, to migrate, or be faced with extinction. Clonal plants would appear to be at a particular disadvantage due to their limited mobility and limited capacity for adaptation. However, they have outlived previous environmental shifts and clonal species have persisted for millenia. Clonal spread offers unique ecological advantages, such as resource sharing, risk sharing, and economies of scale among ramets within genotypes. We suggest that ecological attributes of clonal plants, in tandem with variation in gene regulation through epigenetic mechanisms that facilitate and optimize phenotype variation in response to environmental change may permit them to be well suited to projected conditions.

Binary Star Orbits. V. The Nearby White Dwarf/Red Dwarf Pair 40 Eri BC

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Mason, Brian D.; Hartkopf, William I.; Miles, Korie N.

2017-11-01

A new relative orbit solution with new dynamical masses is determined for the nearby white dwarf-red dwarf pair 40 Eri BC. The period is 230.09 ± 0.68 years. It is predicted to close slowly over the next half-century, getting as close as 1.″32 in early 2066. We determine masses of 0.575 ± 0.018 {{ M }}⊙ for the white dwarf and 0.2041 ± 0.0064 {{ M }}⊙ for the red dwarf companion. The inconsistency of the masses determined by gravitational redshift and dynamical techniques, due to a premature orbit calculation, no longer exists.

The ultracool-field dwarf luminosity-function and space density from the Canada-France Brown Dwarf Survey

Science.gov (United States)

Reylé, C.; Delorme, P.; Willott, C. J.; Albert, L.; Delfosse, X.; Forveille, T.; Artigau, E.; Malo, L.; Hill, G. J.; Doyon, R.

2010-11-01

Context. Thanks to recent and ongoing large scale surveys, hundreds of brown dwarfs have been discovered in the last decade. The Canada-France Brown Dwarf Survey is a wide-field survey for cool brown dwarfs conducted with the MegaCam camera on the Canada-France-Hawaii Telescope. Aims: Our objectives are to find ultracool brown dwarfs and to constrain the field brown-dwarf luminosity function and the mass function from a large and homogeneous sample of L and T dwarfs. Methods: We identify candidates in CFHT/MegaCam i' and z' images and follow them up with pointed near infrared (NIR) imaging on several telescopes. Halfway through our survey we found ~50 T dwarfs and ~170 L or ultra cool M dwarfs drawn from a larger sample of 1400 candidates with typical ultracool dwarfs i'-z' colours, found in 780 square degrees. Results: We have currently completed the NIR follow-up on a large part of the survey for all candidates from mid-L dwarfs down to the latest T dwarfs known with utracool dwarfs' colours. This allows us to draw on a complete and well defined sample of 102 ultracool dwarfs to investigate the luminosity function and space density of field dwarfs. Conclusions: We found the density of late L5 to T0 dwarfs to be 2.0+0.8-0.7 × 10-3 objects pc-3, the density of T0.5 to T5.5 dwarfs to be 1.4+0.3-0.2 × 10-3 objects pc-3, and the density of T6 to T8 dwarfs to be 5.3+3.1-2.2 × 10-3 objects pc-3. We found that these results agree better with a flat substellar mass function. Three latest dwarfs at the boundary between T and Y dwarfs give the high density 8.3+9.0-5.1 × 10-3 objects pc-3. Although the uncertainties are very large this suggests that many brown dwarfs should be found in this late spectral type range, as expected from the cooling of brown dwarfs, whatever their mass, down to very low temperature. Based on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada-France-Hawaii Telescope (CFHT), which is operated by

Invasive clonal plant species have a greater root-foraging plasticity than non-invasive ones.

Science.gov (United States)

Keser, Lidewij H; Dawson, Wayne; Song, Yao-Bin; Yu, Fei-Hai; Fischer, Markus; Dong, Ming; van Kleunen, Mark

2014-03-01

Clonality is frequently positively correlated with plant invasiveness, but which aspects of clonality make some clonal species more invasive than others is not known. Due to their spreading growth form, clonal plants are likely to experience spatial heterogeneity in nutrient availability. Plasticity in allocation of biomass to clonal growth organs and roots may allow these plants to forage for high-nutrient patches. We investigated whether this foraging response is stronger in species that have become invasive than in species that have not. We used six confamilial pairs of native European clonal plant species differing in invasion success in the USA. We grew all species in large pots under homogeneous or heterogeneous nutrient conditions in a greenhouse, and compared their nutrient-foraging response and performance. Neither invasive nor non-invasive species showed significant foraging responses to heterogeneity in clonal growth organ biomass or in aboveground biomass of clonal offspring. Invasive species had, however, a greater positive foraging response in terms of root and belowground biomass than non-invasive species. Invasive species also produced more total biomass. Our results suggest that the ability for strong root foraging is among the characteristics promoting invasiveness in clonal plants.

The Evaluation of the Effect of Multiwall Carbon Nano Tube (MWCNT on In Vitro Proliferation and Shoot Tip Necrosis of Pistachio Rootstock UCB-1 (Pistacia integrima × P. atlantica

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Shahrzad Aghasi Kermani

2017-05-01

Full Text Available UCB-1 (Pistacia atlantica × P. integrima is a commercial rootstock for pistachio in some pistachio plantations across the world. This rootstock is very new in Iran and recently, it has been used commercially in some plantations due to its high growth. Propagation of this rootstock by tissue culture results in many limitations such as shoot tip necrosis (STN and a low proliferation rate. Therefore, any process that leads to improve the proliferation rate and feature will be used in commercial propagation of this rootstock. Nanotubes are widely used in in vitro cultures. For this reason, we used different concentrations of carbon nanotubes (0, 50, 100, 150, 200 µg/l and benzyladenine (0, 0.5, 1, 1.5 and 2 mg/l to improve the proliferation rate and qualitative indices. The results showed that using carbon nanotubes concentration of 200 µg/l with 2mg/l of benzyladenine (BA led to maximum proliferation (4 microshoots per explant, maximum shoot length (3.68 cm and minimum STN (8% and vitrification (this isn’t a word? (0 % percentage.

Demographic consequences of greater clonal than sexual reproduction in Dicentra canadensis.

Science.gov (United States)

Lin, Chia-Hua; Miriti, Maria N; Goodell, Karen

2016-06-01

Clonality is a widespread life history trait in flowering plants that may be essential for population persistence, especially in environments where sexual reproduction is unpredictable. Frequent clonal reproduction, however, could hinder sexual reproduction by spatially aggregating ramets that compete with seedlings and reduce inter-genet pollination. Nevertheless, the role of clonality in relation to variable sexual reproduction in population dynamics is often overlooked. We combined population matrix models and pollination experiments to compare the demographic contributions of clonal and sexual reproduction in three Dicentra canadensis populations, one in a well-forested landscape and two in isolated forest remnants. We constructed stage-based transition matrices from 3 years of census data to evaluate annual population growth rates, λ. We used loop analysis to evaluate the relative contribution of different reproductive pathways to λ. Despite strong temporal and spatial variation in seed set, populations generally showed stable growth rates. Although we detected some pollen limitation of seed set, manipulative pollination treatments did not affect population growth rates. Clonal reproduction contributed significantly more than sexual reproduction to population growth in the forest remnants. Only at the well-forested site did sexual reproduction contribute as much as clonal reproduction to population growth. Flowering plants were more likely to transition to a smaller size class with reduced reproductive potential in the following year than similarly sized nonflowering plants, suggesting energy trade-offs between sexual and clonal reproduction at the individual level. Seed production had negligible effects on growth and tuber production of individual plants. Our results demonstrate that clonal reproduction is vital for population persistence in a system where sexual reproduction is unpredictable. The bias toward clonality may be driven by low fitness returns

Compatibilidade de enxertia de cultivares de marmeleiros com pereiras Compatibility of pear cultivars on quinces rootstocks

Directory of Open Access Journals (Sweden)

Zeni Fonseca Pinto Tomaz

2009-12-01

Full Text Available A insuficiência de estudos sobre compatibilidade de porta-enxertos é um dos fatores limitantes ao desenvolvimento da cultura da pereira (Pyrus sp. no Brasil. A utilização do marmeleiro (Cydonia oblonga como porta-enxerto para a cultura da pereira apresenta inúmeras vantagens, entre as quais a redução do vigor e a rápida entrada em produção; todavia, sua combinação com algumas cultivares copa apresenta problemas de incompatibilidade de enxertia, podendo ocasionar a ruptura do caule das plantas no pomar. Objetivou-se, neste trabalho, avaliar a compatibilidade de enxertia de algumas cultivares de marmeleiros ('Quince C' e 'Adams' com pereiras ('Packham's Triumph' e 'Kieffer'. As variáveis analisadas foram: diâmetro da secção do tronco no ponto de enxertia, 5 cm abaixo e 5 cm acima do ponto de enxertia, diferença do diâmetro entre porta-enxerto e copa, altura das plantas, volume e massa seca da copa e raízes. Além disso, efetuou-se a observação da conexão vascular no ponto de enxertia através da imersão da base das plantas (abaixo do ponto de enxertia, em solução corante de Ácido Fuccínico 0,08%. Concluiu-se que a cultivar 'Packham's Triumph'apresenta compatibilidade de enxertia com o marmeleiro cultivares 'Adams'e 'Quince C', enquanto o híbrido 'Kieffer' apresentou sintomas morfológicos de incompatibilidade de enxertia com o marmeleiro cultivares 'Quince C' e 'Adams'.The lack of studies on compatibility of pear cultivars and rootstocks is one of the limiting factors on the development of the pear crop in Brazil. The use of quinces as rootstocks for pear cultivars has several advantages, among them the reduction in vigor and earlier bearing trees, however, its combination with some scions cultivars results in problems of incompatibility , such as lost of trees of the orchard due to break of the graft union. The objective of this study was to determine the compatibility between pears cvs. Packham's Triumph and Kieffer

Introduction to special issue on the ecology of clonal plants

Czech Academy of Sciences Publication Activity Database

Gross, K. L.; Herben, T.; Klimešová, Jitka

2017-01-01

Roč. 52, 3-4 (2017), s. 265-267 ISSN 1211-9520 Institutional support: RVO:67985939 Keywords : Introduction to special issue * clonal plants * clonal meeting Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 1.017, year: 2016

The brown dwarf kinematics project

Science.gov (United States)

Faherty, Jackie K.

2010-10-01

Brown dwarfs are a recent addition to the plethora of objects studied in Astronomy. With theoretical masses between 13 and 75 MJupiter , they lack sustained stable Hydrogen burning so they never join the stellar main sequence. They have physical properties similar to both planets and low-mass stars so studies of their population inform on both. The distances and kinematics of brown dwarfs provide key statistical constraints on their ages, moving group membership, absolute brightnesses, evolutionary trends, and multiplicity. Yet, until my thesis, fundamental measurements of parallax and proper motion were made for only a relatively small fraction of the known population. To address this deficiency, I initiated the Brown Dwarf Kinematics (BDKP). Over the past four years I have re-imaged the majority of spectroscopically confirmed field brown dwarfs (or ultracool dwarfs---UCDs) and created the largest proper motion catalog for ultracool dwarfs to date. Using new astrometric information I examined population characteristics such as ages calculated from velocity dispersions and correlations between kinematics and colors. Using proper motions, I identified several new wide co-moving companions and investigated binding energy (and hence formation) limitations as well as the frequency of hierarchical companions. Concurrently over the past four years I have been conducting a parallax survey of 84 UCDs including those showing spectral signatures of youth, metal-poor brown dwarfs, and those within 20 pc of the Sun. Using absolute magnitude relations in J,H, and K, I identified overluminous binary candidates and investigated known flux-reversal binaries. Using current evolutionary models, I compared the MK vs J-K color magnitude diagram to model predictions and found that the low-surface gravity dwarfs are significantly red-ward and underluminous of predictions and a handful of late-type T dwarfs may require thicker clouds to account for their scatter.

Prediction for the occurrence of clonal chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Nakano, M.; Kadama, Y.; Ohtaki, K.; Itoh, M.; Awa, A.; Cologne, J.; Nakamura, N.

2003-01-01

Full text: Identical chromosome aberrations among multiple blood lymphocytes in a blood sample (clonal aberrations) are encountered occasionally during cytogenetic examination of radiation-exposed people. Clonal aberrations are found primarily among high-dose exposed people but no systematic surveys were ever conducted. Therefore, the underlying mechanism is unknown. Here we conducted a large-scale screening for detecting clonal aberrations using FISH followed by Q-banding. Examinations of 500 cells from each of 513 A-bomb survivors led us to detect 96 clones. The clonal cell fraction (Cf) varied from 0.6% to 20% among the 500 cells. As the number of clonal event was inversely proportional to Cf, we hypothesized that the progenitor cells vary extensively in the number of offspring that they can produce and relative number of progenitor cells decreases as the increase of treatment, while other genes such as DNA repair proteinsnumber of progenitor cells capable to form clones (Cf >=0.6%) to be 2 (1 to 3) in non-exposed individuals. The number increased to up to 7 among the high-dose exposed survivors. Further, our preliminary results for the origins of 10 clones indicated that both hematopoietic stem cells (HSCs) and mature T cells contributed to the clone formation roughly equally. Thus, the estimated number of 2 in non-exposed individuals is shared as one HSC and one mature T cells. The model could neatly explain the frequency of clones in two reports. Our model predicts that clonal aberrations are rarely found but clonal expansion of T lymphocytes occurs commonly. In fact, clonal expansions of non-aberrant cells are reported using TCR gene rearrangement patterns as a marker. We now understand the rough structure of lymphocyte pool in humans and can predict the probability of detecting a clone if the individual frequency of non-clonal translocations and the number of cells scored are given

White dwarfs - the once and future suns

International Nuclear Information System (INIS)

Trimble, V.

1986-01-01

The history and properties of white dwarfs (Bessel's conclusion that Sirius and Procyon have invisible companions, Clark's discovery of Sirius B, Adams and Russell's study of white dwarf spectra, Chandrasekhar's explanation of white dwarf structure by equations incorporating quantum mechanics and relativity) are treated. Formation of white dwarfs, degeneracy, binary white dwarfs (and novae and supernovae) are explained. A mystery nearly 50 years old regarding the spectrum of the star Greenwich +70 degrees-8247 has been solved: it involves a stationary line phenomenon and a magnetic field of 300-500 million gauss. Processes being studied in white dwarfs and white dwarf models include gravitational settling, accretion, dredge-up, radiation pressure, and diffusive hydrogen burning

Comparison between diploid and tetraploid citrus rootstocks: morphological characterization and growth evaluation

Directory of Open Access Journals (Sweden)

Divanilde Guerra

2014-03-01

Full Text Available Tetraploid citrus rootstocks may present different morphological characteristics and growth when compared to diploid ones. This worked aimed at comparing morphological characteristics and height growth of diploid and tetraploid plants from the rootstocks 'Swingle' citrumelo [C. paradise Macf. x Poncirus trifoliate (L. Raf], citrange 'Troyer' (C. sinensis (L. Osb. x P. trifoliata and citranges 'Fepagro C 13' and 'Fepagro C 37' [C. sinensis cv. Pêra x P. trifoliata] during twelve months. Diploid (2n=18 and tetraploid (2n=36 plants originated from the same seed were identified, cultivated and evaluated every 45 days regarding color, height, petiole length, leaf length and central leaflet width. Significant differences were observed for the evaluated characteristics: the average of petiole length was 1.78 cm in the diploid and 0.99 cm in the tetraploid plants; the average of leaf length was 2.32 cm in the diploid and 2.95 cm in the tetraploid plants; the average of central leaflet width was 1.33 cm in the diploid and 1.69 cm in the tetraploid plants. Moreover, tetraploid plants had darker and thicker leaves than the diploid ones. Variation regarding height was observed and the diploid plants presented higher growth than the tetraploid ones. As tetraploid plants are smaller, have a slow height growth and wider and longer leaves.

WHITE DWARF-RED DWARF SYSTEMS RESOLVED WITH THE HUBBLE SPACE TELESCOPE. II. FULL SNAPSHOT SURVEY RESULTS

International Nuclear Information System (INIS)

Farihi, J.; Hoard, D. W.; Wachter, S.

2010-01-01

Results are presented for a Hubble Space Telescope Advanced Camera for Surveys high-resolution imaging campaign of 90 white dwarfs with known or suspected low-mass stellar and substellar companions. Of the 72 targets that remain candidate and confirmed white dwarfs with near-infrared excess, 43 are spatially resolved into two or more components, and a total of 12 systems are potentially triples. For 68 systems where a comparison is possible, 50% have significant photometric distance mismatches between their white dwarf and M dwarf components, suggesting that white dwarf parameters derived spectroscopically are often biased due to the cool companion. Interestingly, 9 of the 30 binaries known to have emission lines are found to be visual pairs and hence widely separated, indicating an intrinsically active cool star and not irradiation from the white dwarf. There is a possible, slight deficit of earlier spectral types (bluer colors) among the spatially unresolved companions, exactly the opposite of expectations if significant mass is transferred to the companion during the common envelope phase. Using the best available distance estimates, the low-mass companions to white dwarfs exhibit a bimodal distribution in projected separation. This result supports the hypothesis that during the giant phases of the white dwarf progenitor, any unevolved companions either migrate inward to short periods of hours to days, or outward to periods of hundreds to thousands of years. No intermediate projected separations of a few to several AU are found among these pairs. However, a few double M dwarfs (within triples) are spatially resolved in this range, empirically demonstrating that such separations were readily detectable among the binaries with white dwarfs. A straightforward and testable prediction emerges: all spatially unresolved, low-mass stellar and substellar companions to white dwarfs should be in short-period orbits. This result has implications for substellar companion and

Crescimento vegetativo de porta-enxertos de citros produzidos em substratos comerciais Vegetative growth of citrus rootstocks producing in distinct commercials substrates

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Mário Luís Fochesato

2007-08-01

Full Text Available Este trabalho teve o objetivo de avaliar o crescimento vegetativo de porta-enxertos de citros produzidos em diferentes substratos comerciais, mantidos em recipientes de quatro litros. O experimento foi desenvolvido em casa de vegetação, na Estação Experimental Agronômica da UFRGS, em Eldorado do Sul, RS, no período de junho/2003 a março/2004, e seguiu o delineamento experimental de blocos casualizados, testando-se três substratos comerciais: Turfa preta (Comercial 1; cascas processadas e enriquecidas, vermiculita expandida, perlita expandida e turfa (Comercial 2; e casca de pínus compostada e vermiculita (Comercial 3 e três porta-enxertos: ("Trifoliata"; citrangeiro "C13" e limoeiro "Cravo". A irrigação foi feita por gotejamento. Avaliaram-se as seguintes variáveis: diâmetro do colo; altura da parte aérea; número de folhas e área foliar; matéria seca das raízes, da parte aérea e total; conteúdo de nutrientes nas folhas e percentual de porta-enxertos aptos à enxertia. A interpretação dos resultados revelou que o substrato com cascas processadas e enriquecidas, vermiculita expandida, perlita expandida e turfa possibilitou maior desenvolvimento vegetativo aos porta-enxertos utilizados, devido ao maior aporte de nutrientes. Os porta-enxertos mostraram desenvolvimento diferenciado, sendo que o citrangeiro "C13" tem potencial de uso para a diversificação de porta-enxertos na citricultura, devido ao seu desenvolvimento vegetativo.This research was aimed at evaluating the vegetative growth of citrus rootstocks produced in different commercial substrates and cultivated in four liters containers. The experiment was carried out in greenhouse conditions at the Estação Experimental Agronômica of the Universidade Federal do Rio Grande do Sul, from June 2003 to July 2004. Three commercial substrates [black peat (Commercial 1; processed and enriched husks, expanded vermiculite, expanded perlite and peat (Commercial 2; and (pinus

Formation of dwarf ellipticals and dwarf irregular galaxies by interaction of giant galaxies under environmental influence

OpenAIRE

Chattopadhyay, Tanuka; Debsarma, Suma; Karmakar, Pradip; Davoust, Emmanuel

2014-01-01

A model is proposed for the formation of gas-rich dwarf irregular galaxies and gas-poor, rotating dwarf elliptical galaxies following the interaction between two giant galaxies as a function of space density. The formation of dwarf galaxies is considered to depend on a random variable, the tidal index theta, an environmental parameter defined by Karachentsev et al. (2004), such that for theta less than zero, the formation of dwarf irregular galaxy is assured whereas for theta greater than zer...

Asteroseismology of White Dwarf Stars

Science.gov (United States)

Hansen, Carl J.

1997-01-01

The primary purpose of this investigation has been to study various aspects of multimode pulsations in variable white dwarfs. In particular, nonlinear interactions among pulsation modes in white dwarfs (and, to some extent, in other variable stars), analysis of recent observations where such interactions are important, and preliminary work on the effects of crystallization in cool white dwarfs are reported.

SDSS DR7 WHITE DWARF CATALOG

Energy Technology Data Exchange (ETDEWEB)

Kleinman, S. J.; Nitta, A. [Gemini Observatory, 670 North A' ohoku Place, Hilo, HI 96720 (United States); Kepler, S. O.; Pelisoli, Ingrid; Pecanha, Viviane; Costa, J. E. S. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Koester, D. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Kiel, D-24098 Kiel (Germany); Krzesinski, J. [Mt. Suhora Observatory, Pedagogical University of Cracow, ul. Podchorazych 2, 30-084 Cracow (Poland); Dufour, P.; Lachapelle, F.-R.; Bergeron, P. [Departement de Physique, Universite de Montreal, C. P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada); Yip, Ching-Wa [Department of Physics and Astronomy, The Johns Hopkins University, 3701 San Martin Drive, Baltimore, MD 21218 (United States); Harris, Hugh C. [United States Naval Observatory, Flagstaff Station, 10391 West Naval Observatory Road, Flagstaff, AZ 86001-8521 (United States); Eisenstein, Daniel J. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Althaus, L.; Corsico, A., E-mail: hch@nofs.navy.mil [Facultad de Ciencias Astronomicas y Geofisicas, Paseo del Bosque S/N, (1900) La Plata (Argentina)

2013-01-15

We present a new catalog of spectroscopically confirmed white dwarf stars from the Sloan Digital Sky Survey (SDSS) Data Release 7 spectroscopic catalog. We find 20,407 white dwarf spectra, representing 19,712 stars, and provide atmospheric model fits to 14,120 DA and 1011 DB white dwarf spectra from 12,843 and 923 stars, respectively. These numbers represent more than a factor of two increase in the total number of white dwarf stars from the previous SDSS white dwarf catalogs based on DR4 data. Our distribution of subtypes varies from previous catalogs due to our more conservative, manual classifications of each star in our catalog, supplementing our automatic fits. In particular, we find a large number of magnetic white dwarf stars whose small Zeeman splittings mimic increased Stark broadening that would otherwise result in an overestimated log g if fit as a non-magnetic white dwarf. We calculate mean DA and DB masses for our clean, non-magnetic sample and find the DB mean mass is statistically larger than that for the DAs.

The late-M dwarfs

International Nuclear Information System (INIS)

Bessell, M.S.

1991-01-01

Far-red spectra and VRIJHK photometry have been obtained for a sample of late-M dwarfs selected on the basis of large reduced red magnitudes from the LHS Catalog. Half of the stars in the three faintest 1 mag bins are late-M stars, the other red stars are metallic-hydride subdwarfs. Relations between various colors for the late-M dwarfs are investigated. Of all the colors I - K most reliably correlates with spectral type. FeH bands near 9900 A are clearly seen in the spectra of all dwarf stars later than M5. Two stars cooler than VB10, and similar in temperature to LHS2924 have been identified; both have H-alpha in emission and appear variable in magnitude and R - I color; one is a flare star. The other stars are of earlier spectral type and resemble W359 and VB8. The observed MI, I - K main sequence is in good agreement with the IG theoretical main sequence of Stringfellow, and the faintest stars could be about 0.09 solar mass red dwarfs or lower mass brown dwarfs. 65 refs

Understanding Brown Dwarf Variability

Science.gov (United States)

Marley, Mark S.

2013-01-01

Surveys of brown dwarf variability continue to find that roughly half of all brown dwarfs are variable. While variability is observed amongst all types of brown dwarfs, amplitudes are typically greatest for L-T transition objects. In my talk I will discuss the possible physical mechanisms that are responsible for the observed variability. I will particularly focus on comparing and contrasting the effects of changes in atmospheric thermal profile and cloud opacity. The two different mechanisms will produce different variability signatures and I will discuss the extent to which the current datasets constrain both mechanisms. By combining constraints from studies of variability with existing spectral and photometric datasets we can begin to construct and test self-consistent models of brown dwarf atmospheres. These models not only aid in the interpretation of existing objects but also inform studies of directly imaged giant planets.

Evolution models of helium white dwarf-main-sequence star merger remnants: the mass distribution of single low-mass white dwarfs

Science.gov (United States)

Zhang, Xianfei; Hall, Philip D.; Jeffery, C. Simon; Bi, Shaolan

2018-02-01

It is not known how single white dwarfs with masses less than 0.5Msolar -- low-mass white dwarfs -- are formed. One way in which such a white dwarf might be formed is after the merger of a helium-core white dwarf with a main-sequence star that produces a red giant branch star and fails to ignite helium. We use a stellar-evolution code to compute models of the remnants of these mergers and find a relation between the pre-merger masses and the final white dwarf mass. Combining our results with a model population, we predict that the mass distribution of single low-mass white dwarfs formed through this channel spans the range 0.37 to 0.5Msolar and peaks between 0.45 and 0.46Msolar. Helium white dwarf--main-sequence star mergers can also lead to the formation of single helium white dwarfs with masses up to 0.51Msolar. In our model the Galactic formation rate of single low-mass white dwarfs through this channel is about 8.7X10^-3yr^-1. Comparing our models with observations, we find that the majority of single low-mass white dwarfs (<0.5Msolar) are formed from helium white dwarf--main-sequence star mergers, at a rate which is about $2$ per cent of the total white dwarf formation rate.

EROS 2 proper motion survey a field brown dwarf and an L dwarf companion to LHS 102

CERN Document Server

Goldman, B; Forveille, T; Afonso, C; Alard, C; Albert, J N; Andersen, J; Ansari, R; Aubourg, E; Bareyre, P; Bauer, F; Beaulieu, J P; Borsenberger, J; Bouquet, A; Char, S; Charlot, X; Couchot, F; Coutures, C; Derue, F; Ferlet, R; Fouqué, P; Glicenstein, J F; Gould, A; Graff, D S; Gros, M H; Haïssinski, J; Hamilton, J C; Hardin, D P; De Kat, J; Kim, A; Lasserre, T; Lesquoy, E; Loup, C; Magneville, C; Mansoux, B; Marquette, J B; Martín, E L; Maurice, E; Milshtein, A I; Moniez, M; Palanque-Delabrouille, Nathalie; Perdereau, O; Prévôt, L; Regnault, N; Rich, J; Spiro, Michel; Vidal-Madjar, A; Virgoux, L; Zylberajch, S

1999-01-01

We report the discovery of two L dwarfs (the new spectral class defined for dwarfs cooler than the M type) in a two-epoch CCD proper motion survey of 413 square degrees, complemented by infrared photometry from DENIS. One of them has a strong lithium line and is therefore a brown dwarf. The other is a common proper motion companion to the mid-M dwarf LHS 102 (GJ 1001), which has a well determined trigonometric parallax. LHS 102B is thus the coolest L dwarf of known distance and luminosity. Its infrared absolute photometry are very well reproduced by the Allard et al DUSTY models.

Addition of nitrogen had no effect on yield and quality of apples in an high density orchard carrying a dwarf rootstock A adição de nitrogênio não afetou o rendimento e a qualidade de maçãs em pomar com alta densidade e porta-enxerto anão

Directory of Open Access Journals (Sweden)

Paulo Roberto Ernani

2008-12-01

Full Text Available The effect of N addition on apple yield and quality may vary according to the tree vigor. Apple trees developed over vigorous rootstocks had shown no response to N application in Brazil. In this study it was evaluated the effect of N addition to the soil on yield and quality of ´Royal Gala´ apples grafted on a dwarf rootstock (M.9. The orchard was planted in 1995 (2,857 trees ha-1 on an Oxisol containing 40 g kg-1 of organic matter and pH 6.0. The experiment was carried out from 1998 up to 2005. Treatments consisted of rates of N (0, 50, 100 and 150 kg ha-1 year-1 from 1998 to 2001, and respectively 0, 100, 200 and 300 kg ha-1 afterwards, all broadcasted within the tree row in two equal splits, at bud break and after harvest, as ammonium sulfate. Addition of N to the soil had no effect on fruit yield over the six years regardless of the applied rate. Averaged across treatments and years, fruit yield was 52.3 t ha-1. Nitrogen in the leaves (average of 24 g kg-1 or in the fruits (average of 346 mg kg-1 as well as some attributes related to fruit quality (color, firmness, acidity, soluble solids, physiological disorders were unaffected by N addition. Some plant parameters related to tree vigor, however, grew higher with the increase on N rate. Thus, it is not necessary to apply N to deep Brazilian soils containing high organic matter in order to assure good fruit quality and yield on high-density orchards carrying dwarf rootstocks probably because the N required for tree growth and fruit production is supplied from soil organic matter decay.O efeito da adição de N ao solo no rendimento e na qualidade de maçãs pode variar em função do vigor das plantas. Experimentos conduzidos no Brasil com macieiras cultivadas sobre porta-enxertos vigorosos não têm apresentado aumento no rendimento de frutos pela aplicação de N. Este trabalho objetivou avaliar o efeito da aplicação de N no rendimento e na qualidade de frutos de macieira cultivada em

On the ecological genetics of the clonal perennial Agrostis stolonifera

NARCIS (Netherlands)

Kik, Christoffel

1987-01-01

There have to date been few studies specifically addressed to the evolution of clonal organisms. The present study attempts to fill this gap and aims to analyse the distribution pattern of a clonal plant species, using the wide-spread grass Agrostis stolonifera L.(Creeping Bent) as a model species.

Clonal neoantigens elicit T cell immunoreactivity and sensitivity to immune checkpoint blockade

Science.gov (United States)

McGranahan, Nicholas; Furness, Andrew J. S.; Rosenthal, Rachel; Ramskov, Sofie; Lyngaa, Rikke; Saini, Sunil Kumar; Jamal-Hanjani, Mariam; Wilson, Gareth A.; Birkbak, Nicolai J.; Hiley, Crispin T.; Watkins, Thomas B. K.; Shafi, Seema; Murugaesu, Nirupa; Mitter, Richard; Akarca, Ayse U.; Linares, Joseph; Marafioti, Teresa; Henry, Jake Y.; Van Allen, Eliezer M.; Miao, Diana; Schilling, Bastian; Schadendorf, Dirk; Garraway, Levi A.; Makarov, Vladimir; Rizvi, Naiyer A.; Snyder, Alexandra; Hellmann, Matthew D.; Merghoub, Taha; Wolchok, Jedd D.; Shukla, Sachet A.; Wu, Catherine J.; Peggs, Karl S.; Chan, Timothy A.; Hadrup, Sine R.; Quezada, Sergio A.; Swanton, Charles

2016-01-01

As tumors grow, they acquire mutations, some of which create neoantigens that influence the response of patients to immune checkpoint inhibitors. We explored the impact of neoantigen intratumor heterogeneity (ITH) on antitumor immunity. Through integrated analysis of ITH and neoantigen burden, we demonstrate a relationship between clonal neoantigen burden and overall survival in primary lung adenocarcinomas. CD8+ tumor-infiltrating lymphocytes reactive to clonal neoantigens were identified in early-stage non–small cell lung cancer and expressed high levels of PD-1. Sensitivity to PD-1 and CTLA-4 blockade in patients with advanced NSCLC and melanoma was enhanced in tumors enriched for clonal neoantigens. T cells recognizing clonal neoantigens were detectable in patients with durable clinical benefit. Cytotoxic chemotherapy–induced subclonal neoantigens, contributing to an increased mutational load, were enriched in certain poor responders. These data suggest that neoantigen heterogeneity may influence immune surveillance and support therapeutic developments targeting clonal neoantigens. PMID:26940869

Infrared photometry of cool white dwarfs

International Nuclear Information System (INIS)

Wickramasinghe, D.T.; Allen, D.A.; Bessell, M.S.

1982-01-01

The results are presented of a search for the effects of pressure induced H 2 dipole opacity on the infrared JHK magnitudes of cool white dwarfs. LHS 1126 is found to be a very cool (Tsub(e) approximately 4250 K) DC white dwarf with a H rich atmospheric composition dominated by H 2 dipole opacity in the infrared. JHK photometry also favours a H rich atmospheric composition for the DK white dwarfs LP 658-2 and W 489. The surprisingly high proportion of hydrogen rich white dwarfs in the sample appears to suggest that the mechanism which inhibits the accretion of hydrogen in the hotter helium stars becomes less effective at low (Tsub(e) approximately 3 + ion in cool hydrogen rich white dwarf atmospheres is pointed out and it is suggested that the opacity due to this ion may be responsible for the blanketing observed in the U and B magnitudes of some cool white dwarfs. (author)

The Hunt for Missing Dwarf Galaxies

Science.gov (United States)

Kohler, Susanna

2015-11-01

Theories of galaxy formation and evolution predict that there should be significantly more dwarf galaxies than have been observed. Are our theories wrong? Or are dwarf galaxies just difficult to detect? Recent results from a survey of a galaxy cluster 62 million light-years away suggest there may be lots of undiscovered dwarf galaxies hiding throughout the universe!Hiding in FaintnessThe missing dwarf problem has had hints of a resolution with the recent discovery of Ultra-Diffuse Galaxies (UDGs) in the Coma and Virgo galaxy clusters. UDGs have low masses and large radii, resulting in a very low surface brightness that makes them extremely difficult to detect. If many dwarfs are UDGs, this could well explain why weve been missing them!But the Coma and Virgo galaxy clusters are similar in that theyre both very massive. Are there UDGs in other galaxy clusters as well? To answer this question, an international team of scientists is running the Next Generation Fornax Survey (NGFS), a survey searching for faint dwarf galaxies in the central 30 square degrees of the Fornax galaxy cluster.The NGFS uses near-UV and optical observations from the Dark Energy Camera mounted on the 4m Blanco Telescope in Chile. The survey is still underway, but in a recent publication led by Roberto P. Muoz (Institute of Astrophysics at the Pontifical Catholic University of Chile), the team has released an overview of the first results from only the central 3 square degrees of the NGFS field.Surprising DetectionGalaxy radii vs. their absolute i-band magnitudes, for the dwarfs found in NGFS as well as other stellar systems in the nearby universe. The NGFS dwarfs are similar to the ultra-diffuse dwarfs found in the Virgo and Coma clusters, but are several orders of magnitude fainter. [Muoz et al. 2015]In just this small central field, the team has found an astounding 284 low-surface-brightness dwarf galaxy candidates 158 of them previously undetected. At the bright end of this sample are dwarf

Interação enxerto e porta-enxerto na incidência da resinose do cajueiro Effect of cashew clone used as rootstocks and scions on gummosis incidence in cashew plants

Directory of Open Access Journals (Sweden)

José Emilson Cardoso

2010-09-01

Full Text Available A expansão do cajueiro-anão-precoce no Brasil vem promovendo baixa diversidade genética dos genótipos usados como enxerto e porta-enxerto, ensejando vulnerabilidade da cultura às vicissitudes bióticas como a resinose (Lasiodiplodia theobromae, principal doença do cajueiro no semiárido nordestino. Estima-se que cerca de meio milhão de mudas de cajueiro-anão-precoce sejam produzidas anualmente, sendo a grande maioria delas produzida de propágulos enxertados sobre plântulas oriundas de sementes do clone CCP 06. A principal estratégia de manejo da resinose é o plantio de clones resistentes. Entretanto, entre os aspectos que contribuem para sucessivas epidemias da resinose, destaca-se a falta de estudos de interações genotípicas entre enxerto e porta-enxerto. Este estudo objetivou avaliar o efeito de combinações de clones de cajueiro-anão-precoce usados como enxerto e porta-enxerto na incidência da resinose. Sementes de plantas de polinização aberta de seis clones selecionados foram usadas para produção de porta-enxerto. Os clones comerciais CCP 76 (suscetível e BRS 226 (resistente foram usados como enxertos. O experimento foi realizado obedecendo ao delineamento de blocos ao acaso, no esquema fatorial 2 x 6, com quatro repetições e nove plantas por parcela do tipo quadrada, sob condições de elevada pressão da doença, em Pio IX-PI. Três anos após o plantio definitivo, a incidência (I e a severidade (S (escala de 0 a 4 da resinose foram superiores no clone CCP 76 (I = 97% e S=2,10 em relação ao BRS 226 (I = 33% e S=0,36, independentemente do porta-enxerto. O clone CP 06 como porta-enxerto foi o único que reduziu a incidência e a severidade da resinose, independentemente do genótipo do enxerto. Este clone foi capaz de reduzir a severidade da resinose do clone CCP 76 (S=2,10 como enxerto em quase 30%.The expansion of early dwarf cashew (EDC crop in Brazil has promoted a reduced genetic diversity of cashew

Lists of semi-dwarf cereal stocks

International Nuclear Information System (INIS)

1984-01-01

The lists are prepared in relation to the Co-ordinated Research Programme. At the first Research Co-ordination Meeting on evaluation of cereal semi-dwarf mutants for cross breeding, March 1981, programme participants were requested to list semi-dwarf mutants available at their institutes including also non-induced semi-dwarf stocks being used in cross-breeding programme for short stature. List-I is prepared from such lists provided by programme participants. Further it was requested to name breeders and institutes providing characteristics of the listed semi-dwarf stocks. List-II gives that information. In the List-I: Parents of semi-dwarf stocks derived from cross breeding, are shown in brackets. In column ''Culm length'', figures are in cm and those of parent cultivars are shown in brackets

Pulsations in white dwarf stars

OpenAIRE

Van Grootel, Valérie; Fontaine, Gilles; Brassard, Pierre; Dupret, Marc-Antoine

2017-01-01

I will present a description of the six distinct families of pulsating white dwarfs that are currently known. Pulsations are present at various stages of the evolution (from hot, pre-white dwarfs to cool white dwarfs), at various stellar masses, and for various atmospheric compositions. In all of them, a mechanism linked to opacity changes along the evolution drives the oscillations. The existence of these oscillations offers the opportunity to apply asteroseismology for constraining physics ...

White dwarfs in the WTS: Eclipsing binaries

Directory of Open Access Journals (Sweden)

Burleigh M.R.

2013-04-01

Full Text Available We have identified photometric white dwarf candidates in the WFCAM transit survey through a reduced proper motion versus colour approach. Box-fitting with parameters adjusted to detect the unique signature of a white dwarf + planet/brown dwarf transit/eclipse event was performed, as well as looking for variability due to the irradiation of the companions atmosphere by the white dwarf's high UV flux. We have also performed a simple sensitivity analysis in order to assess the ability of the survey to detect companions to white dwarfs via the transit method.

Effect of rootstock on the scion of Hevea brasiliensis through metabolic analysis of latex samples by 1H NMR

Directory of Open Access Journals (Sweden)

Eduardo Sanches Pereira do Nascimento

2011-01-01

Full Text Available In this study, the effect of rootstock on grafting through metabolomic analysis of latex (Hevea brasiliensis samples was verified by 1H nuclear magnetic resonance (NMR and multivariate data analysis. Sixteen metabolites present in the latex cytosol were characterized by NMR. PCA analysis showed that the latex samples of the RR and GR groups can be differentiated. The GR group samples present a metabolic profile similar to the RR group samples, while the RG group is in an intermediate position between RR and GG groups. Sucrose and formate contributed greatly to the separation obtained by PCA, presenting a good correlation between the results. 1H NMR was an efficient technique to differentiate latex samples from different types of rootstocks and grafting and in the future could be used to predict rubber production by latex analysis.

Habitability of planets around red dwarf stars.

Science.gov (United States)

Heath, M J; Doyle, L R; Joshi, M M; Haberle, R M

1999-08-01

Recent models indicate that relatively moderate climates could exist on Earth-sized planets in synchronous rotation around red dwarf stars. Investigation of the global water cycle, availability of photosynthetically active radiation in red dwarf sunlight, and the biological implications of stellar flares, which can be frequent for red dwarfs, suggests that higher plant habitability of red dwarf planets may be possible.

A systematic search for brown dwarfs orbiting nearby stars

International Nuclear Information System (INIS)

Henry, T.J.; Mccarthy, D.W. Jr.

1990-01-01

Survey data for brown dwarf and stellar companions relative to known M dwarf stars within 5 pc north of -30 deg are analyzed. A region 0.2 to 5 arcsec in radius around 27 stars at the IR H and K bands are examined using IR speckle interferometry. The frequency of binary versus single M dwarfs in the solar neighborhood is examined. The IR mass-magnitude relations and mass-luminosity-age relation are studied. The data reveal that there are 19 single M dwarfs, 8 M dwarf binaries, 1 M dwarf triple system, and 1 M dwarf in a triple system for M dwarfs within 5 pc north of -30 deg. Also of the 27 M dwarfs studied none was found to have a brown dwarf companion. 64 refs

Effect of different rootstocks on growth, chlorophyll a fluorescence and mineral composition of two grafted scions of tomato

NARCIS (Netherlands)

Goto, R.; Miguel, de A.; Marsal, J.I.; Gorbe, E.; Calatayud, A.

2013-01-01

Two tomato scions (cvs. ‘Raf’ and ‘Gorety’) were grafted on three different rootstocks: S. torvum, ‘Beaufort’ (Lycopersicum esculentum × Lycopersicum hirsutum) and intermediate grafting of eggplant ‘Cristal’ between tomato and S. torvum (double graft). Plants were grown in Mediterranean greenhouse

The Metallicity of Void Dwarf Galaxies

Science.gov (United States)

Kreckel, K.; Croxall, K.; Groves, B.; van de Weygaert, R.; Pogge, R. W.

2015-01-01

The current ΛCDM cosmological model predicts that galaxy evolution proceeds more slowly in lower density environments, suggesting that voids are a prime location to search for relatively pristine galaxies that are representative of the building blocks of early massive galaxies. To test the assumption that void galaxies are more pristine, we compare the evolutionary properties of a sample of dwarf galaxies selected specifically to lie in voids with a sample of similar isolated dwarf galaxies in average density environments. We measure gas-phase oxygen abundances and gas fractions for eight dwarf galaxies (Mr > -16.2), carefully selected to reside within the lowest density environments of seven voids, and apply the same calibrations to existing samples of isolated dwarf galaxies. We find no significant difference between these void dwarf galaxies and the isolated dwarf galaxies, suggesting that dwarf galaxy chemical evolution proceeds independent of the large-scale environment. While this sample is too small to draw strong conclusions, it suggests that external gas accretion is playing a limited role in the chemical evolution of these systems, and that this evolution is instead dominated mainly by the internal secular processes that are linking the simultaneous growth and enrichment of these galaxies.

Evolution of White Dwarf Stars

OpenAIRE

L. G. Althaus

2001-01-01

This paper is aimed at presenting the main results we have obtained for the study of the evoution of white dwarf stars. The calculations are carried out by means of a detailed evolutionary code based on an updated physical description. In particular, we briefly discuss the results for the evolution of white dwarfs of different stellar masses and chemical composition, and the evolution of whit e dwarfs in the framework of a varying gravitational constant G scenario as well.

Calibrating Detailed Chemical Analysis of M dwarfs

Science.gov (United States)

Veyette, Mark; Muirhead, Philip Steven; Mann, Andrew; Brewer, John; Allard, France; Homeier, Derek

2018-01-01

The ability to perform detailed chemical analysis of Sun-like F-, G-, and K-type stars is a powerful tool with many applications including studying the chemical evolution of the Galaxy, assessing membership in stellar kinematic groups, and constraining planet formation theories. Unfortunately, complications in modeling cooler stellar atmospheres has hindered similar analysis of M-dwarf stars. Large surveys of FGK abundances play an important role in developing methods to measure the compositions of M dwarfs by providing benchmark FGK stars that have widely-separated M dwarf companions. These systems allow us to empirically calibrate metallicity-sensitive features in M dwarf spectra. However, current methods to measure metallicity in M dwarfs from moderate-resolution spectra are limited to measuring overall metallicity and largely rely on astrophysical abundance correlations in stellar populations. In this talk, I will discuss how large, homogeneous catalogs of precise FGK abundances are crucial to advancing chemical analysis of M dwarfs beyond overall metallicity to direct measurements of individual elemental abundances. I will present a new method to analyze high-resolution, NIR spectra of M dwarfs that employs an empirical calibration of synthetic M dwarf spectra to infer effective temperature, Fe abundance, and Ti abundance. This work is a step toward detailed chemical analysis of M dwarfs at a similar precision achieved for FGK stars.

Observations of Superwinds in Dwarf Galaxies

Science.gov (United States)

Marlowe, A. T.; Heckman, T. M.; Wyse, R.; Schommer, R.

1993-12-01

Dwarf galaxies are important in developing our understanding of the formation and evolution of galaxies, and of the structure in the universe. The concept of supernova-driven mass outflows is a vital ingredient in theories of the structure and evolution of dwarfs galaxies. We have begun a detailed multi-waveband search for outflows in starbursting dwarf galaxies, and have obtained Fabry-Perot images and Echelle spectra of 20 nearby actively-star-forming dwarf galaxies. In about half the sample, the Fabry-Perot Hα images show loops and filaments with sizes of one to a few kpc. The Echelle spectra taken through the loops and filaments show kinematics consistent with expanding bubble-like structures. We describe these data, and present seven dwarfs in our sample that have the strongest evidence of outflows.

Evidence for the Translocation of Gibberellin A_3 and Gibberellin-Like Substances in Grafts between Normal, Dwarf_1 and Dwarf_5 Seedlings of Zea mays L.

OpenAIRE

M., Katsumi; D.E., Foard; B.O., Phinney; Biology Department, International Christian University; Department of Botany and Plant Pathology, Purdue University; Department of Biology, University of California

1983-01-01

Approach grafts were made between the cut surfaces of mesocotyls from normal and dwarf seedlings of Zea mays L. (maize). The dwarfs were the non-allelic single gene gibberellin mutants, dwarf_1 and dwarf_5. The graft combinations were normal-normal, normal-dwarf_1, normal-dwarf_5, dwarf_1-dwarf_1, dwarf_5-dwarf_5, and dwarf_1-dwarf_5. The grafts were used to demonstrate the movement of gibberellin-like substances across the union. GA_3, added to one member of the graft, resulted in leaf-sheat...

Metabolic heterogeneity in clonal microbial populations.

Science.gov (United States)

Takhaveev, Vakil; Heinemann, Matthias

2018-02-21

In the past decades, numerous instances of phenotypic diversity were observed in clonal microbial populations, particularly, on the gene expression level. Much less is, however, known about phenotypic differences that occur on the level of metabolism. This is likely explained by the fact that experimental tools probing metabolism of single cells are still at an early stage of development. Here, we review recent exciting discoveries that point out different causes for metabolic heterogeneity within clonal microbial populations. These causes range from ecological factors and cell-inherent dynamics in constant environments to molecular noise in gene expression that propagates into metabolism. Furthermore, we provide an overview of current methods to quantify the levels of metabolites and biomass components in single cells. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

PREFACE: 16th European White Dwarfs Workshop

Science.gov (United States)

Garcia-Berro, Enrique; Hernanz, Margarita; Isern, Jordi; Torres, Santiago

2009-07-01

The 16th European Workshop on White Dwarfs was held in Barcelona, Spain, from 30 June to 4 July 2008 at the premises of the UPC. Almost 120 participants from Europe (France, Germany, United Kingdom, Italy, and several others), America (USA, Canada, Argentina, Brazil, and Chile), and other continents (Australia, South Africa, . . . ) attended the workshop. Among these participants were the most relevant specialists in the field. The topics covered by the conference were: White dwarf structure and evolution Progenitors and Planetary Nebulae White dwarfs in binaries: cataclysmic variables, double degenerates and other binaries White dwarfs, dust disks and planetary systems Atmospheres, chemical composition, magnetic fields Variable white dwarfs White dwarfs in stellar clusters and the halo White Dwarfs as SNIa progenitors The programme included 54 talks, and 45 posters. The oral presentations were distributed into the following sessions: Luminosity function, mass function and populations White dwarf structure and evolution White dwarf ages White dwarf catalogs and surveys Central stars of planetary nebulae Supernovae progenitors White dwarfs in novae and CVs Physical processes in white dwarfs and magnetic white dwarfs Disks, dust and planets around white dwarfs Pulsating white dwarfs Additionally we had a special open session about Spitzer and white dwarfs. The Proceedings of the 16th European Workshop on White Dwarfs are representative of the current state-of-the-art of the research field and include new and exciting results. We acknowledge the very positive attitude of the attendants to the workshop, which stimulated very fruitful discussions that took place in all the sessions and after the official schedule. Also, the meeting allowed new collaborations tp start that will undoubtedly result in significant advances in the research field. We also acknowledge the willingness of the participants to deliver their contributions before the final deadline. We sincerely

Effect of Salinity Stress on Concentrations of Nutrition Elements in Almond (Prunus Dulcis 'Shokofeh', 'Sahand' Cultivars and '13-40' Genotype Budded on GF677 Rootstock

Directory of Open Access Journals (Sweden)

A. Momenpour

2016-02-01

Full Text Available Introduction: Almond (Prunus amygdalus B. is one of the most important crops consumed as a dry fruit and it is mainly adaptable to arid and semi-arid regions mostly suffering from salinity stress (8. Soils with dry humidity regime are dominant in Iran and in the world at large and mostly include regions with more evaporation than precipitation. This in turn leads to increased salinity of the soil (9 and 10. Based on available reports, roughly 12.5% of land areas in Iran are saline, which overwhelmingly contain sodium, while more than 800 million hectares of land area on the earth (6% of overall global land area are affected by salinity (9 and 10. Therefore, compound of rootstock and scion may be used as one of the influence factors in sensitivity or tolerance to salinity of planted fruit trees including almonds (8 and 11. In recent years, for various reasons including the uniformity of trees, instead of sexual rootstock, vegetative rootstock is used. Rootstock GF677 an inter-specific hybrid (Almond Peach is propagated asexually as clone (8. It has been reported that rootstock GF677 is tolerant to salinity while rootstock nemagard (P. persica X P. davidiana is sensitive to salinity (16. It has been reported that rootstock GF677 tolerated salinity (5.5 ds/m, (19 or 5.2 ds/m (17 and 14.However, as plant species and different cultivars within the same plant species vary considerably in their tolerance to salinity (10, properly selecting plants and/or cultivars that can be grown well under adverse conditions, created in the root zone by salinization, is the most efficient and environmentally friendly agricultural practice for a more permanent solution of the problem of salinity (10. Despite the presence of information on the effect of salinity on concentration of nutrition elements of almond cultivars leaves and roots, tolerantscion/rootstock combinationshave not been introduced for this plant. Therefore, the aim of the present study is to

Clonal integration facilitates spread of Paspalum paspaloides from terrestrial to cadmium-contaminated aquatic habitats.

Science.gov (United States)

Luo, F-L; Xing, Y-P; Wei, G-W; Li, C-Y; Yu, F-H

2017-11-01

Cadmium (Cd) is a hazardous environmental pollutant with high toxicity to plants, which has been detected in many wetlands. Clonal integration (resource translocation) between connected ramets of clonal plants can increase their tolerance to stress. We hypothesised that clonal integration facilitates spread of amphibious clonal plants from terrestrial to Cd-contaminated aquatic habitats. The spread of an amphibious grass Paspalum paspaloides was simulated by growing basal older ramets in uncontaminated soil connected (allowing integration) or not connected (preventing integration) to apical younger ramets of the same fragments in Cd-contaminated water. Cd contamination of apical ramets of P. paspaloides markedly decreased growth and photosynthetic capacity of the apical ramets without connection to the basal ramets, but did not decrease these properties with connection. Cd contamination did not affect growth of the basal ramets without connection to the apical ramets, but Cd contamination of 4 and 12 mg·l -1 significantly increased growth with connection. Consequently, clonal integration increased growth of the apical ramets, basal ramets and whole clones when the apical ramets were grown in Cd-contaminated water of 4 and 12 mg·l -1 . Cd was detected in the basal ramets with connection to the apical ramets, suggesting Cd could be translocated due to clonal integration. Clonal integration, most likely through translocation of photosynthates, can support P. paspaloides to spread from terrestrial to Cd-contaminated aquatic habitats. Amphibious clonal plants with a high ability for clonal integration are particularly useful for re-vegetation of degraded aquatic habitats caused by Cd contamination. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

SpeX Spectroscopy of Unresolved Very Low-Mass Binaries. I. Identification of Seventeen Candidate Binaries Straddling the L Dwarf/T Dwarf Transition

OpenAIRE

Burgasser, Adam J.; Cruz, Kelle L.; Cushing, Michael C.; Gelino, Christopher R.; Looper, Dagny L.; Faherty, Jacqueline K.; Kirkpatrick, J. Davy; Reid, I. Neill

2009-01-01

We report the identification of 17 candidate brown dwarf binaries whose components straddle the L dwarf/T dwarf transition. These sources were culled from a large near-infrared spectral sample of L and T dwarfs observed with the Infrared Telescope Facility SpeX spectrograph. Candidates were selected on the basis of spectral ratios which segregate known (resolved) L dwarf/T dwarf pairs from presumably single sources. Composite templates, constructed by combining 13581 pairs of absolute flux-ca...

Quantum liquid signatures in dwarf stars

Energy Technology Data Exchange (ETDEWEB)

Gabadadze, Gregory; Pirtskhalava, David, E-mail: gg32@nyu.edu, E-mail: dmp371@nyu.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10003 (United States)

2009-05-15

We develop further the proposal of arXiv:0806.3692 that a new state of matter - charged condensate of spin-0 nuclei - may exist in helium-core dwarf stars. The charged condensate and its fluctuations are described by an effective field theory Lagrangian. The spectrum of bosonic fluctuations is gapped, while electrons, at temperatures of interest, give rise to gapless excitations near the Fermi surface. These properties determine the evolution of the dwarfs with condensed cores. In particular, we show that such dwarf stars would cool significantly faster than their crystallized counterparts. As a result, the luminosity function for the helium-core dwarfs will have a sharp drop-off after the condensation. It is tempting to interpret the recently discovered abrupt termination of a sequence of 24 helium-core dwarf candidates in NGC 6397 as a signature of the charged condensation.

Are commercial sweet cherry rootstocks adapted to climate change? Short-term waterlogging and CO2 effects on sweet cherry cv. 'Burlat'.

Science.gov (United States)

Pérez-Jiménez, Margarita; Hernández-Munuera, María; Piñero, M Carmen; López-Ortega, Gregorio; Del Amor, Francisco M

2018-05-01

High CO 2 is able to ameliorate some negative effects due to climate change and intensify others. This study involves the sweet cherry (Prunus avium) cultivar 'Burlat' grafted on the 'Mariana 2624', 'Adara' and 'LC 52' rootstocks. In a climate chamber at two CO 2 concentrations, ambient (400 µmol mol -1 ) and elevated (800 µmol mol -1 ), the plants were submitted to waterlogging for 7 d, followed by 7 d of recovery after drainage. Waterlogging drastically decreased the rate of photosynthesis, significantly endangering plant survival, particularly for the 'LC 52' and 'Adara' rootstocks. 'Mariana 2624' was also clearly affected by waterlogging that increased lipid peroxidation and the Cl - and SO 4 2- concentrations in all the studied plants. Nevertheless, CO 2 was able to overcome this reduction in photosynthesis, augmenting growth, increasing soluble sugars and starch, raising turgor and regulating the concentrations of Cl - and SO 4 2- , while lowering the NO 3 - concentration in leaves of all the studied rootstocks. In concordance with these results, the proline levels indicated a more intense stress at control CO 2 than at high CO 2 for waterlogged plants. 'Mariana 2624' was more resistant to waterlogging than 'Adara', and both were more resistant than 'LC 52' in control CO 2 conditions; this clearly enhanced the chance of survival under hypoxia. © 2017 John Wiley & Sons Ltd.

Milky Way red dwarfs in the BoRG survey; galactic scale-height and the distribution of dwarf stars in WFC3 imaging

International Nuclear Information System (INIS)

Holwerda, B. W.; Bouwens, R.; Trenti, M.; Clarkson, W.; Sahu, K.; Bradley, L.; Stiavelli, M.; Pirzkal, N.; Ryan, R.; De Marchi, G.; Andersen, M.

2014-01-01

We present a tally of Milky Way late-type dwarf stars in 68 Wide Field Camera 3 (WFC3) pure-parallel fields (227 arcmin 2 ) from the Brightest of Reionizing Galaxies survey for high-redshift galaxies. Using spectroscopically identified M-dwarfs in two public surveys, the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey and the Early Release Science mosaics, we identify a morphological selection criterion using the half-light radius (r 50 ), a near-infrared J – H, G – J color region where M-dwarfs are found, and a V – J relation with M-dwarf subtype. We apply this morphological selection of stellar objects, color-color selection of M-dwarfs, and optical-near-infrared color subtyping to compile a catalog of 274 M-dwarfs belonging to the disk of the Milky Way with a limiting magnitude of m F125W < 24(AB). Based on the M-dwarf statistics, we conclude that (1) the previously identified north-south discrepancy in M-dwarf numbers persists in our sample; there are more M-dwarfs in the northern fields on average than in southern ones, (2) the Milky Way's single disk scale-height for M-dwarfs is 0.3-4 kpc, depending on subtype, (3) the scale-height depends on M-dwarf subtype with early types (M0-4) high scale-height (z 0 = 3-4 kpc) and later types M5 and above in the thin disk (z 0 = 0.3-0.5 kpc), (4) a second component is visible in the vertical distribution, with a different, much higher scale-height in the southern fields compared to the northern ones. We report the M-dwarf component of the Sagittarius stream in one of our fields with 11 confirmed M-dwarfs, seven of which are at the stream's distance. In addition to the M-dwarf catalog, we report the discovery of 1 T-dwarfs and 30 L-dwarfs from their near-infrared colors. The dwarf scale-height and the relative low incidence in our fields of L- and T-dwarfs in these fields makes it unlikely that these stars will be interlopers in great numbers in color-selected samples of high-redshift galaxies

Milky Way red dwarfs in the BoRG survey; galactic scale-height and the distribution of dwarf stars in WFC3 imaging

Energy Technology Data Exchange (ETDEWEB)

Holwerda, B. W.; Bouwens, R. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Trenti, M. [Kavli Institute for Cosmology and Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Clarkson, W. [Department of Natural Sciences College of Arts, Sciences and Letters, University of Michigan-Dearborn 4901 Evergreen Road, Dearborn, MI 48128 (United States); Sahu, K.; Bradley, L.; Stiavelli, M.; Pirzkal, N.; Ryan, R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); De Marchi, G. [European Space Agency, ESA-ESTEC, Keplerlaan 1, 2200 AG Noordwijk (Netherlands); Andersen, M., E-mail: holwerda@strw.leidenuniv.nl [UJF-Grenoble 1/CNRS-INSU, Institut de Planétologie et d' Astrophysique de Grenoble (IPAG) UMR 5274, F-38041 Grenoble (France)

2014-06-10

We present a tally of Milky Way late-type dwarf stars in 68 Wide Field Camera 3 (WFC3) pure-parallel fields (227 arcmin{sup 2}) from the Brightest of Reionizing Galaxies survey for high-redshift galaxies. Using spectroscopically identified M-dwarfs in two public surveys, the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey and the Early Release Science mosaics, we identify a morphological selection criterion using the half-light radius (r {sub 50}), a near-infrared J – H, G – J color region where M-dwarfs are found, and a V – J relation with M-dwarf subtype. We apply this morphological selection of stellar objects, color-color selection of M-dwarfs, and optical-near-infrared color subtyping to compile a catalog of 274 M-dwarfs belonging to the disk of the Milky Way with a limiting magnitude of m {sub F125W} < 24(AB). Based on the M-dwarf statistics, we conclude that (1) the previously identified north-south discrepancy in M-dwarf numbers persists in our sample; there are more M-dwarfs in the northern fields on average than in southern ones, (2) the Milky Way's single disk scale-height for M-dwarfs is 0.3-4 kpc, depending on subtype, (3) the scale-height depends on M-dwarf subtype with early types (M0-4) high scale-height (z {sub 0} = 3-4 kpc) and later types M5 and above in the thin disk (z {sub 0} = 0.3-0.5 kpc), (4) a second component is visible in the vertical distribution, with a different, much higher scale-height in the southern fields compared to the northern ones. We report the M-dwarf component of the Sagittarius stream in one of our fields with 11 confirmed M-dwarfs, seven of which are at the stream's distance. In addition to the M-dwarf catalog, we report the discovery of 1 T-dwarfs and 30 L-dwarfs from their near-infrared colors. The dwarf scale-height and the relative low incidence in our fields of L- and T-dwarfs in these fields makes it unlikely that these stars will be interlopers in great numbers in color-selected samples of

An overview of white dwarf stars

Directory of Open Access Journals (Sweden)

Charpinet S.

2013-03-01

Full Text Available We present a brief summary of what is currently known about white dwarf stars, with an emphasis on their evolutionary and internal properties. As is well known, white dwarfs represent the end products of stellar evolution for the vast majority of stars and, as such, bear the signatures of past events (such as mass loss, mixing phases, loss and redistribution of angular momentum, and thermonuclear burning that are of essential importance in the evolution of stars in general. In addition, white dwarf stars represent ideal testbeds for our understanding of matter under extreme conditions, and work on their constitutive physics (neutrino production rates, conductive and radiative opacities, interior liquid/solid equations of state, partially ionized and partially degenerate envelope equations of state, diffusion coefficients, line broadening mechanisms is still being actively pursued. Given a set of constitutive physics, cooling white dwarfs can be used advantageously as cosmochronometers. Moreover, the field has been blessed by the existence of four distinct families of pulsating white dwarfs, each mapping a different evolutionary phase, and this allows the application of the asteroseismological method to probe and test their internal structure and evolutionary state. We set the stage for the reviews that follow on cooling white dwarfs as cosmochronometers and physics laboratories, as well as on the properties of pulsating white dwarfs and the asteroseismological results that can be inferred.

A CROSS-MATCH OF 2MASS AND SDSS. II. PECULIAR L DWARFS, UNRESOLVED BINARIES, AND THE SPACE DENSITY OF T DWARF SECONDARIES

International Nuclear Information System (INIS)

Geissler, Kerstin; Metchev, Stanimir; Kirkpatrick, J. Davy; Berriman, G. Bruce; Looper, Dagny

2011-01-01

We present the completion of a program to cross-correlate the Sloan Digital Sky Survey Data Release 1 (SDSS DR1) and Two-Micron All-Sky Survey (2MASS) Point Source Catalog in search for extremely red L and T dwarfs. The program was initiated by Metchev and collaborators, who presented the findings on all newly identified T dwarfs in SDSS DR1 and estimated the space density of isolated T0-T8 dwarfs in the solar neighborhood. In the current work, we present most of the L dwarf discoveries. Our red-sensitive (z - J ≥ 2.75 mag) cross-match proves to be efficient in detecting peculiarly red L dwarfs, adding two new ones, including one of the reddest known L dwarfs. Our search also nets a new peculiarly blue L7 dwarf and, surprisingly, two M8 dwarfs. We further broaden our analysis to detect unresolved binary L or T dwarfs through spectral template fitting to all L and T dwarfs presented here and in the earlier work by Metchev and collaborators. We identify nine probable binaries, six of which are new and eight harbor likely T dwarf secondaries. We combine this result with current knowledge of the mass ratio distribution and frequency of substellar companions to estimate an overall space density of 0.005-0.05 pc -3 for individual T0-T8 dwarfs.

Larch Dwarf Mistletoe (FIDL)

Science.gov (United States)

Jerome S. Beatty; Gregory M. Filip; Robert L. Mathiason

1997-01-01

Larch dwarf mistletoe (Arceuthobium laricis (Piper) St. John) is a common and damaging parasite of western larch (Larix occidentalis Nutt.) in the Pacific Northwest and southern British Columbia. Larch dwarf mistletoe occurs commonly throughout the range of western larch in British Columbia, northern and central Idaho, western Montana and east of the Cascades in...

Clonal diversity analysis using SNP microarray: a new prognostic tool for chronic lymphocytic leukemia.

Science.gov (United States)

Zhang, Linsheng; Znoyko, Iya; Costa, Luciano J; Conlin, Laura K; Daber, Robert D; Self, Sally E; Wolff, Daynna J

2011-12-01

Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease. The methods currently used for monitoring CLL and determining conditions for treatment are limited in their ability to predict disease progression, patient survival, and response to therapy. Although clonal diversity and the acquisition of new chromosomal abnormalities during the disease course (clonal evolution) have been associated with disease progression, their prognostic potential has been underappreciated because cytogenetic and fluorescence in situ hybridization (FISH) studies have a restricted ability to detect genomic abnormalities and clonal evolution. We hypothesized that whole genome analysis using high resolution single nucleotide polymorphism (SNP) microarrays would be useful to detect diversity and infer clonal evolution to offer prognostic information. In this study, we used the Infinium Omni1 BeadChip (Illumina, San Diego, CA) array for the analysis of genetic variation and percent mosaicism in 25 non-selected CLL patients to explore the prognostic value of the assessment of clonal diversity in patients with CLL. We calculated the percentage of mosaicism for each abnormality by applying a mathematical algorithm to the genotype frequency data and by manual determination using the Simulated DNA Copy Number (SiDCoN) tool, which was developed from a computer model of mosaicism. At least one genetic abnormality was identified in each case, and the SNP data was 98% concordant with FISH results. Clonal diversity, defined as the presence of two or more genetic abnormalities with differing percentages of mosaicism, was observed in 12 patients (48%), and the diversity correlated with the disease stage. Clonal diversity was present in most cases of advanced disease (Rai stages III and IV) or those with previous treatment, whereas 9 of 13 patients without detected clonal diversity were asymptomatic or clinically stable. In conclusion, SNP microarray studies with simultaneous evaluation

Star Formation Histories of Nearby Dwarf Galaxies

OpenAIRE

Grebel, Eva K.

2000-01-01

Properties of nearby dwarf galaxies are briefly discussed. Dwarf galaxies vary widely in their star formation histories, the ages of their subpopulations, and in their enrichment history. Furthermore, many dwarf galaxies show evidence for spatial variations in their star formation history; often in the form of very extended old populations and radial gradients in age and metallicity. Determining factors in dwarf galaxy evolution appear to be both galaxy mass and environment. We may be observi...

Relationship between endogenous hormonal content and somatic organogenesis in callus of peach (Prunus persica L. Batsch) cultivars and Prunus persica×Prunus dulcis rootstocks.

Science.gov (United States)

Pérez-Jiménez, Margarita; Cantero-Navarro, Elena; Pérez-Alfocea, Francisco; Le-Disquet, Isabel; Guivarc'h, Anne; Cos-Terrer, José

2014-05-01

The relationship between endogenous hormones content and the induction of somatic peach plant was studied. To induce multiple shoots from callus derived from the base of stem explants of the scion cultivars 'UFO-3', 'Flariba' and 'Alice Bigi', and the peach×almond rootstocks 'Garnem' and 'GF677', propagated plants were cultured on Murashige and Skoog salts augmented with 0.1mgL(-1) of indolebutyric acid, 1mgL(-1) of 6-benzylaminopurine and 3% sucrose. The highest regeneration rate was obtained with the peach×almond rootstocks. Endogenous levels of abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin (Z), zeatin riboside (ZR), ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), salicylic acid (SA), and jasmonic acid (JA) were analyzed in the organogenic callus. Lower levels of several hormones, namely Z, ZR, ABA, and ACC were found in the peach×almond rootstock compared to peach cultivars, while IAA and SA presented inconclusive returns. These results suggest that the difference in somatic organogenesis capacity observed in peach and peach×almond hybrids is markedly affected by the endogenous hormonal content of the studied genotypes. Copyright © 2014 Elsevier GmbH. All rights reserved.

Performance of 'Valencia' Orange (Citrus sinensis [L.] Osbeck) on 17 rootstocks in a trial severely affected by huanglongbing

Science.gov (United States)

Valencia orange (Citrus sinensis L. Osbeck) was grown on 17 rootstocks through seven years of age and the first four harvest seasons in a central Florida field trial severely affected by huanglongbing (HLB) disease. All trees in the trial had huanglongbing symptoms and were shown by Polymerase chain...

Testing the potential significance of different scion/rootstock genotype combinations on the ecology of old cultivated olive trees in the southeast Mediterranean area.

Science.gov (United States)

Barazani, Oz; Waitz, Yoni; Tugendhaft, Yizhar; Dorman, Michael; Dag, Arnon; Hamidat, Mohammed; Hijawi, Thameen; Kerem, Zohar; Westberg, Erik; Kadereit, Joachim W

2017-02-06

A previous multi-locus lineage (MLL) analysis of SSR-microsatellite data of old olive trees in the southeast Mediterranean area had shown the predominance of the Souri cultivar (MLL1) among grafted trees. The MLL analysis had also identified an MLL (MLL7) that was more common among rootstocks than other MLLs. We here present a comparison of the MLL combinations MLL1 (scion)/MLL7 (rootstock) and MLL1/MLL1 in order to investigate the possible influence of rootstock on scion phenotype. A linear regression analysis demonstrated that the abundance of MLL1/MLL7 trees decreases and of MLL1/MLL1 trees increases along a gradient of increasing aridity. Hypothesizing that grafting on MLL7 provides an advantage under certain conditions, Akaike information criterion (AIC) model selection procedure was used to assess the influence of different environmental conditions on phenotypic characteristics of the fruits and oil of the two MLL combinations. The most parsimonious models indicated differential influences of environmental conditions on parameters of olive oil quality in trees belonging to the MLL1/MLL7 and MLL1/MLL1 combinations, but a similar influence on fruit characteristics and oil content. These results suggest that in certain environments grafting of the local Souri cultivar on MLL7 rootstocks and the MLL1/MLL1 combination result in improved oil quality. The decreasing number of MLL1/MLL7 trees along an aridity gradient suggests that use of this genotype combination in arid sites was not favoured because of sensitivity of MLL7 to drought. Our results thus suggest that MLL1/MLL7 and MLL1/MLL1 combinations were selected by growers in traditional rain-fed cultivation under Mediterranean climate conditions in the southeast Mediterranean area.

Evolution models of helium white dwarf--main-sequence star merger remnants: the mass distribution of single low-mass white dwarfs

OpenAIRE

Zhang, Xianfei; Hall, Philip D.; Jeffery, C. Simon; Bi, Shaolan

2017-01-01

It is not known how single white dwarfs with masses less than 0.5Msolar -- low-mass white dwarfs -- are formed. One way in which such a white dwarf might be formed is after the merger of a helium-core white dwarf with a main-sequence star that produces a red giant branch star and fails to ignite helium. We use a stellar-evolution code to compute models of the remnants of these mergers and find a relation between the pre-merger masses and the final white dwarf mass. Combining our results with ...

Hemlock Dwarf Mistletoe (FIDL)

Science.gov (United States)

Paul E. Hennon; Jerome S. Beatty; Diane Hildebrand

2001-01-01

Hemlock dwarf mistletoe, Arceuthobium tsugense (Rosendahl) G.N. Jones, causes a serious disease of western hemlock and several other tree species along the Pacific Coast of North America. This small, seed-bearing plant lives exclusively as a parasite on living trees. Throughout its range, hemlock dwarf mistletoe occurs in patch-like patterns in the forests. Some...

Uncovering the Number and Clonal Dynamics of Mesp1 Progenitors during Heart Morphogenesis

Directory of Open Access Journals (Sweden)

Samira Chabab

2016-01-01

Full Text Available The heart arises from distinct sources of cardiac progenitors that independently express Mesp1 during gastrulation. The precise number of Mesp1 progenitors that are specified during the early stage of gastrulation, and their clonal behavior during heart morphogenesis, is currently unknown. Here, we used clonal and mosaic tracing of Mesp1-expressing cells combined with quantitative biophysical analysis of the clonal data to define the number of cardiac progenitors and their mode of growth during heart development. Our data indicate that the myocardial layer of the heart derive from ∼250 Mesp1-expressing cardiac progenitors born during gastrulation. Despite arising at different time points and contributing to different heart regions, the temporally distinct cardiac progenitors present very similar clonal dynamics. These results provide insights into the number of cardiac progenitors and their mode of growth and open up avenues to decipher the clonal dynamics of progenitors in other organs and tissues.

Analysis of allelic expression patterns in clonal somatic cells by single-cell RNA-seq.

Science.gov (United States)

Reinius, Björn; Mold, Jeff E; Ramsköld, Daniel; Deng, Qiaolin; Johnsson, Per; Michaëlsson, Jakob; Frisén, Jonas; Sandberg, Rickard

2016-11-01

Cellular heterogeneity can emerge from the expression of only one parental allele. However, it has remained controversial whether, or to what degree, random monoallelic expression of autosomal genes (aRME) is mitotically inherited (clonal) or stochastic (dynamic) in somatic cells, particularly in vivo. Here we used allele-sensitive single-cell RNA-seq on clonal primary mouse fibroblasts and freshly isolated human CD8 + T cells to dissect clonal and dynamic monoallelic expression patterns. Dynamic aRME affected a considerable portion of the cells' transcriptomes, with levels dependent on the cells' transcriptional activity. Notably, clonal aRME was detected, but it was surprisingly scarce (aRME occurs transiently within individual cells, and patterns of aRME are thus primarily scattered throughout somatic cell populations rather than, as previously hypothesized, confined to patches of clonally related cells.

Merging white dwarfs and thermonuclear supernovae.

Science.gov (United States)

van Kerkwijk, M H

2013-06-13

Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and the suggestion that these supernovae instead result from mergers of carbon-oxygen white dwarfs, including those that produce sub-Chandrasekhar-mass remnants. I then turn to possible observational tests, in particular, those that test the absence or presence of electron captures during the burning.

A radio-pulsing white dwarf binary star.

Science.gov (United States)

Marsh, T R; Gänsicke, B T; Hümmerich, S; Hambsch, F-J; Bernhard, K; Lloyd, C; Breedt, E; Stanway, E R; Steeghs, D T; Parsons, S G; Toloza, O; Schreiber, M R; Jonker, P G; van Roestel, J; Kupfer, T; Pala, A F; Dhillon, V S; Hardy, L K; Littlefair, S P; Aungwerojwit, A; Arjyotha, S; Koester, D; Bochinski, J J; Haswell, C A; Frank, P; Wheatley, P J

2016-09-15

White dwarfs are compact stars, similar in size to Earth but approximately 200,000 times more massive. Isolated white dwarfs emit most of their power from ultraviolet to near-infrared wavelengths, but when in close orbits with less dense stars, white dwarfs can strip material from their companions and the resulting mass transfer can generate atomic line and X-ray emission, as well as near- and mid-infrared radiation if the white dwarf is magnetic. However, even in binaries, white dwarfs are rarely detected at far-infrared or radio frequencies. Here we report the discovery of a white dwarf/cool star binary that emits from X-ray to radio wavelengths. The star, AR Scorpii (henceforth AR Sco), was classified in the early 1970s as a δ-Scuti star, a common variety of periodic variable star. Our observations reveal instead a 3.56-hour period close binary, pulsing in brightness on a period of 1.97 minutes. The pulses are so intense that AR Sco's optical flux can increase by a factor of four within 30 seconds, and they are also detectable at radio frequencies. They reflect the spin of a magnetic white dwarf, which we find to be slowing down on a 10 7 -year timescale. The spin-down power is an order of magnitude larger than that seen in electromagnetic radiation, which, together with an absence of obvious signs of accretion, suggests that AR Sco is primarily spin-powered. Although the pulsations are driven by the white dwarf's spin, they mainly originate from the cool star. AR Sco's broadband spectrum is characteristic of synchrotron radiation, requiring relativistic electrons. These must either originate from near the white dwarf or be generated in situ at the M star through direct interaction with the white dwarf's magnetosphere.

Air method measurements of apple vessel length distributions with improved apparatus and theory

Science.gov (United States)

Shabtal Cohen; John Bennink; Mel Tyree

2003-01-01

Studies showing that rootstock dwarfing potential is related to plant hydraulic conductance led to the hypothesis that xylem properties are also related. Vessel length distribution and other properties of apple wood from a series of varieties were measured using the 'air method' in order to test this hypothesis. Apparatus was built to measure and monitor...

White-dwarf-white-dwarf galactic background in the LISA data

International Nuclear Information System (INIS)

Edlund, Jeffrey A.; Tinto, Massimo; Krolak, Andrzej; Nelemans, Gijs

2005-01-01

LISA (Laser Interferometer Space Antenna) is a proposed space mission, which will use coherent laser beams exchanged between three remote spacecraft to detect and study low-frequency cosmic gravitational radiation. In the low part of its frequency band, the LISA strain sensitivity will be dominated by the incoherent superposition of hundreds of millions of gravitational wave signals radiated by inspiraling white-dwarf binaries present in our own Galaxy. In order to estimate the magnitude of the LISA response to this background, we have simulated a synthesized population that recently appeared in the literature. Our approach relies on entirely analytic expressions of the LISA time-delay interferometric responses to the gravitational radiation emitted by such systems, which allows us to implement a computationally efficient and accurate simulation of the background in the LISA data. We find the amplitude of the galactic white-dwarf binary background in the LISA data to be modulated in time, reaching a minimum equal to about twice that of the LISA noise for a period of about two months around the time when the Sun-LISA direction is roughly oriented towards the Autumn equinox. This suggests that, during this time period, LISA could search for other gravitational wave signals incoming from directions that are away from the galactic plane. Since the galactic white-dwarf background will be observed by LISA not as a stationary but rather as a cyclostationary random process with a period of 1 yr, we summarize the theory of cyclostationary random processes, present the corresponding generalized spectral method needed to characterize such process, and make a comparison between our analytic results and those obtained by applying our method to the simulated data. We find that, by measuring the generalized spectral components of the white-dwarf background, LISA will be able to infer properties of the distribution of the white-dwarf binary systems present in our Galaxy

Response of dwarf mistletoe-infested ponderosa pine to thinning: 2. Dwarf mistletoe propagation.

Science.gov (United States)

Lewis F. Roth; James W. Barrett

1985-01-01

Propagation of dwarf mistletoe in ponderosa pine saplings is little influenced by thinning overly dense stands to 250 trees per acre. Numerous plants that appear soon after thinning develop from formerly latent plants in the suppressed under-story. Subsequently, dwarf mistletoe propagates nearly as fast as tree crowns enlarge but the rate differs widely among trees....

HIV genetic information and clonal growth

Science.gov (United States)

Based on an analysis of blood cells from five HIV-infected individuals, NCI researchers have identified more than 2,400 HIV DNA insertion sites. Analysis of these sites showed that there is extensive clonal expansion (growth) of HIV infected cells.

Effects of Salinity Stress on Morphological and Physiological Characteristics of some Local Landrace and Inter specific Hybrids of Cucurbits Seedlings as Rootstocks

Directory of Open Access Journals (Sweden)

Ali Farhadi

2017-12-01

Full Text Available Introduction: Salinity stress is regarded as one of the most important abiotic factors in plant limiting growth, particularly in arid and semi-arid regions. The reduction of plant growth by salinity stress has been well documented. When water supply is limited, plant structure is modified by increasing the root: shoot ratio. To reduce of losses in vegetative growth and production of plant and to improve water use efficiency under saline conditions in high-yielding genotypes grafting them onto rootstocks could bereduced the effect of saline stress on plant shoot. Grafting is a routine technique in continuous cropping systems. Most of the species of cucurbits are distributed in the dry regions. The objective of this studywas investigated the effectiveness of salinity stress on accessions of cucurbita and hybrid inter specific which enter from another country to Iran. Materials and Methods: This research was conducted in laboratory and greenhouse at the Research Center of Agricultural and Natural Resources of Isfahan during 2013-2014 growing season. A factorial experiment based on completely randomized design with three replications was conducted for rootstock and irrigation water salinity.. In the first experiment 25 seeds of rootstocks were sown in petri dishes with 10 cm diameter and irrigated by 10 ml of saline water. Rootstocks included 20 different local landraces and interspecific hybrids (C.moschata cv. Isfahan and Koshk, C.pepo cv. Alvar, Tiran, Koshk and Asgharabad, C. maxima cv. Kermanshah, Shahreza, Mohamadiyeh and Alvar, Lagenaria Siceraria, Luffa cylindrica, Trichosanthes cucumerina, RZ-Ferro, Es113, Ews910, Ews909, Ews913, 426 and Es152. Salinity stress was 6 levels (0, 2, 4, 6, 8 and 10 ds/m of NaCl. Germination, diameter of stem, height of root and stem, shoot and root fresh mass, vigor index and root: shoot ratio were evaluated. In the second experiment seeds were sown in plastic pot by soil media. Seedlings were irrigated daily

Clonal Spread in Second Growth Stands of Coast Redwood, Sequoia sempervirens

Science.gov (United States)

Vladimir Douhovnikoff; Richard S. Dodd

2007-01-01

Coast redwood (Sequoia sempervirens) is one of the rare conifers to reproduce successfully through clonal spread. The importance of this mode of reproduction in stand development is largely unknown. Understanding the importance of clonal spread and the spatial structure of clones is crucial for stand management strategies that would aim to maximize...

EuroClonality/BIOMED-2 guidelines for interpretation and reporting of Ig/TCR clonality testing in suspected lymphoproliferations

NARCIS (Netherlands)

Langerak, A. W.; Groenen, P. J. T. A.; Brüggemann, M.; Beldjord, K.; Bellan, C.; Bonello, L.; Boone, E.; Carter, G. I.; Catherwood, M.; Davi, F.; Delfau-Larue, M.-H.; Diss, T.; Evans, P. A. S.; Gameiro, P.; Garcia Sanz, R.; Gonzalez, D.; Grand, D.; Håkansson, A.; Hummel, M.; Liu, H.; Lombardia, L.; Macintyre, E. A.; Milner, B. J.; Montes-Moreno, S.; Schuuring, E.; Spaargaren, M.; Hodges, E.; van Dongen, J. J. M.

2012-01-01

PCR-based immunoglobulin (Ig)/T-cell receptor (TCR) clonality testing in suspected lymphoproliferations has largely been standardized and has consequently become technically feasible in a routine diagnostic setting. Standardization of the pre-analytical and post-analytical phases is now essential to

What fraction of white dwarfs are members of binary systems?

International Nuclear Information System (INIS)

Holberg, J B

2009-01-01

White dwarfs were originally discovered as the subordinate faint companions of bright nearby stars (i.e. Sirius B and 40 Eri B). Several general categories of binary systems involving white dwarfs are recognized: Sirius-like systems, where the white dwarf may be difficult to detect, binary systems containing white dwarfs and low mass stars, where the white dwarf is often readily discerned; and double degenerate systems. Different modes of white dwarf discovery influence our perception of both the overall binary fraction and the nature of these systems; proper motion surveys emphasize resolved systems, while photometric surveys emphasize unresolved systems containing relatively hot white dwarfs. Recent studies of the local white dwarf population offer some hope of achieving realistic estimates of the relative number of binary systems containing white dwarfs. A sample of 132 white dwarfs within 20 pc indicates that an individual white dwarf has a probability of 32 ± 8% of occurring within a binary or multiple star system.

Effects of fertilization and rootstock on nutrient status and fruit set in sour cherry Prunus cerasus 'Stevnsbaer'

DEFF Research Database (Denmark)

Jensen, N. L.; Toldam-Andersen, Torben; Dencker, Ivar Blücher

2007-01-01

The purpose of this experiment was to investigate the effects of two potassium fertilization treatments on fruit set and flower bud, flower and bract leaf nutrient concentrations in Prunus cerasus 'Stevnsbaer' on Prunus avium and 'Colt' rootstocks. Single applications of KNO3 or KCl were applied ...

Screening of clonal chromosome aberrations present in A-bomb survivors by FISH method

International Nuclear Information System (INIS)

Nakano, Mimako; Kodama, Yoshiaki; Ito, Masahiro; Otaki, Kazuo; Nakamura, Nori

1997-01-01

Significance of FISH method for detection of clonal chromosome aberration was reviewed. A clonal chromosome aberration is derived from one abnormal cell clone and gives the influence on the frequency of the aberration. As well, the size and frequency of the aberration give an important information concerning lymphocyte kinetics. FISH method is meaningful for detection of the clonal aberration. Fifteen kinds of clonal aberrations were detected in A-bomb survivors, of which 10 were specifically detected by the method, indicating that its detection rate was 2-3 time as high as the ordinary method. The results were those on the DNA probe on no.1, no.2 and no.3 chromosomes, which consisting of about 23% of the genome. (K.H.)

Rhizome elongation and seagrass clonal growth

NARCIS (Netherlands)

Marbà, N.; Duarte, C.M.

1998-01-01

A compilation of published and original data on rhizome morphometry, horizontal and vertical elongation rates and branching patterns for 27 seagrass species developing in 192 seagrass stands allowed an examination of the variability of seagrass rhizome and clonal growth programmes across and within

Drug hypersensitivity in clonal mast cell disorders

DEFF Research Database (Denmark)

Bonadonna, P; Pagani, M; Aberer, W

2015-01-01

and severity of immediate hypersensitivity reactions. Mastocytosis in adults is associated with a history of anaphylaxis in 22-49%. Fatal anaphylaxis has been described particularly following hymenoptera stings, but also occasionally after the intake of drugs such as nonsteroidal anti-inflammatory drugs......, opioids and drugs in the perioperative setting. However, data on the frequency of drug hypersensitivity in mastocytosis and vice versa are scarce and evidence for an association appears to be limited. Nevertheless, clonal MC disorders should be ruled out in cases of severe anaphylaxis: basal serum...... tryptase determination, physical examination for cutaneous mastocytosis lesions, and clinical characteristics of anaphylactic reaction might be useful for differential diagnosis. In this position paper, the ENDA group performed a literature search on immediate drug hypersensitivity reactions in clonal MC...

Clonal relatedness between lobular carcinoma in situ and synchronous malignant lesions

Science.gov (United States)

2012-01-01

Introduction Lobular carcinoma in situ (LCIS) has been accepted as a marker of risk for the development of invasive breast cancer, yet modern models of breast carcinogenesis include LCIS as a precursor of low-grade carcinomas. We provide evidence favoring a clonal origin for LCIS and synchronous estrogen receptor-positive malignant lesions of the ductal and lobular phenotype. Methods Patients with prior LCIS undergoing mastectomy were identified preoperatively from 2003 to 2008. Specimens were widely sampled, and frozen blocks were screened for LCIS and co-existing malignant lesions, and were subject to microdissection. Samples from 65 patients were hybridized to the Affymetrix SNP 6.0 array platform. Cases with both an LCIS sample and an associated ductal carcinoma in situ (DCIS) or invasive tumor sample were evaluated for patterns of somatic copy number changes to assess evidence of clonal relatedness. Results LCIS was identified in 44 of the cases, and among these a DCIS and/or invasive lesion was also identified in 21 cases. A total of 17 tumor pairs had adequate DNA/array data for analysis, including nine pairs of LCIS/invasive lobular cancer, four pairs of LCIS/DCIS, and four pairs of LCIS/invasive ductal cancer. Overall, seven pairs (41%) were judged to be clonally related; in five (29%) evidence suggested clonality but was equivocal, and five (29%) were considered independent. Clonal pairs were observed with all matched lesion types and low and high histological grades. We also show anecdotal evidence of clonality between a patient-matched triplet of LCIS, DCIS, and invasive ductal cancer. Conclusion Our results support the role of LCIS as a precursor in the development of both high-grade and low-grade ductal and lobular cancers. PMID:22776144

Biological/Horticultural Internship Final Report

Science.gov (United States)

Palmer, Shane R.; Spencer, Lashelle (Editor)

2017-01-01

A study was conducted to determine water use requirements of genetically modified (GMO) dwarf plum. GMO plum and unmodified standard plum plants were grown in a controlled environment chamber under varying CO2 concentrations (400 ppm, 1500 ppm, and 5000 ppm). Pepper plants were also grown in the chamber for additional comparison. Leaf stomatal conductance, biomass accumulation, soil moisture and pot weights were measured; Stomatal conductance of GMO plum and pepper plants decreased at sustained elevated CO2 concentrations. The stomatal conductance rates of the standard plums, however, increased at sustained elevated CO2 concentrations. Further data analysis (statistical analysis, biomass, soil moisture and pot weight measurements) is ongoing and required to gain better understanding of the data. An additional proof-of-concept study was undertaken to determine the feasibility of grafting unmodified standard plum scions onto genetically modified rootstocks as a propagation method. Bud grafts were performed on three GMO plum rootstocks: NASA-5, NASA-10, and NASA-11. All of the standard plum buds grafted onto NASA-5 and NASA-10 rootstocks began growing, indicating that this grafting method is highly successful for the formation of a graft union and initial bud growth. However, bud growth during stem elongation was curtailed on several grafts due to a combination of nutritional deficiency and physical damage/obstruction of the grafted tissues. Bud growth on the NASA-5 rootstock occurred sooner than in grafts on the NASA-10 rootstock, while only one bud graft has shown growth on the NASA-11 rootstock thus far. These marked differences in the onset of bud growth suggest genotypic differences between the rootstocks may affect bud graft vigor. Mature standard plum scions grown on the NASA-5 rootstock appeared to retain most or all of the physical characteristics of the standard plum donor plant.

Activity-induced radial velocity variation of M dwarf stars

DEFF Research Database (Denmark)

Andersen, Jan Marie; Korhonen, Heidi Helena

2012-01-01

that can drown out a planetary signature. Cool, low-mass M dwarf stars can be highly active, which can make detection of potentially habitable planets around these stars difficult. We investigate radial velocity variations caused by different activity (spot) patterns on M dwarf stars in order to determine...... the limits of detectability for small planets orbiting active M dwarfs. We report on our progress toward the aim of answering the following questions: What types of spot patterns are realistic for M dwarf stars? What effect will spots have on M dwarf RV measurements? Can jitter from M dwarf spots mimic...... planetary signals? What is the ideal observing wavelength to reduce M dwarf jitter?...

NEW COOLING SEQUENCES FOR OLD WHITE DWARFS

International Nuclear Information System (INIS)

Renedo, I.; Althaus, L. G.; GarcIa-Berro, E.; Miller Bertolami, M. M.; Romero, A. D.; Corsico, A. H.; Rohrmann, R. D.

2010-01-01

We present full evolutionary calculations appropriate for the study of hydrogen-rich DA white dwarfs. This is done by evolving white dwarf progenitors from the zero-age main sequence, through the core hydrogen-burning phase, the helium-burning phase, and the thermally pulsing asymptotic giant branch phase to the white dwarf stage. Complete evolutionary sequences are computed for a wide range of stellar masses and for two different metallicities, Z = 0.01, which is representative of the solar neighborhood, and Z = 0.001, which is appropriate for the study of old stellar systems, like globular clusters. During the white dwarf cooling stage, we self-consistently compute the phase in which nuclear reactions are still important, the diffusive evolution of the elements in the outer layers and, finally, we also take into account all the relevant energy sources in the deep interior of the white dwarf, such as the release of latent heat and the release of gravitational energy due to carbon-oxygen phase separation upon crystallization. We also provide colors and magnitudes for these sequences, based on a new set of improved non-gray white dwarf model atmospheres, which include the most up-to-date physical inputs like the Lyα quasi-molecular opacity. The calculations are extended down to an effective temperature of 2500 K. Our calculations provide a homogeneous set of evolutionary cooling tracks appropriate for mass and age determinations of old DA white dwarfs and for white dwarf cosmochronology of the different Galactic populations.

Calorie restriction and dwarf mice in gerontological research.

Science.gov (United States)

McKee Alderman, J; DePetrillo, Michael A; Gluesenkamp, Angela M; Hartley, Antonia C; Verhoff, S Veronica; Zavodni, Katherine L; Combs, Terry P

2010-01-01

What aging process is delayed by calorie restriction (CR) and mutations that produce long-lived dwarf mice? From 1935 until 1996, CR was the only option for increasing the maximum lifespan of laboratory rodents. In 1996, the mutation producing the Ames dwarf mouse (Prop-1(-/-)) was reported to increase lifespan. Since 1996, other gene mutations that cause dwarfism or lower body weight have been reported to increase the lifespan of mice. The recent discovery of long-lived mutant dwarf mice provides an opportunity to investigate common features between CR and dwarf models. Both CR and dwarf mutations increase insulin sensitivity. Elevated insulin sensitivity reduces oxidative stress, a potential cause of aging. The elevation of liver insulin sensitivity by the hormone adiponectin in CR and long-lived dwarf mice can lower endogenous glucose production and raise fatty acid oxidation. Adiponectin reduction of plasma glucose in CR and long-lived dwarf mice can thereby lower age-related increases in oxidative damage and cancer. Copyright 2009 S. Karger AG, Basel.

Implementation of Microfluidic Chip Electrophoresis for the Detection of B-cell Clonality

Directory of Open Access Journals (Sweden)

Vazan M

2016-04-01

Full Text Available Introduction: A clonal population of B-cells is defined as those cells arising from the mitotic division of a single somatic cell with the same rearrangement of immunoglobulin genes. This gives rise to DNA markers for each individual lymphoid cell and its progenies and enables us to study clonality in different B-cell malignancies using multiplex polymerase chain reaction - PCR. The BIOMED-2 protocol has been implemented for clonality detection in lymphoproliferative diseases and exploits multiplex PCR reaction, subsequently analyzed by heteroduplex analysis (HDA using polyacrylamide gel electrophoresis (PAGE. With the advent of miniaturization and automation of molecular biology methods, lab-on-chip technologies were developed and replace partially the conventional approaches. We tested device for microfluidic chip, which is used for B-cells clonality analysis, using a PCR reaction for three subregions called frameworks (FR of the immunoglobulin heavy locus (IGH gene.

Starbursts in Blue compact dwarf galaxies

International Nuclear Information System (INIS)

Thuan, T.X.

1987-01-01

We summarize all the arguments for a bursting mode of star formation in blue compact dwarf galaxies. We show in particular how spectral synthesis of far ultraviolet spectra of Blue compact dwarf galaxy constitutes a powerful way for studying the star formation history in these galaxies. Blue compact dwarf galaxy luminosity functions show jumps and discontinuities. These jumps act like fossil records of the star-forming bursts, helping us to count and date the bursts

Merging White Dwarfs and Thermonuclear Supernovae

OpenAIRE

van Kerkwijk, Marten H.

2012-01-01

Thermonuclear supernovae result when interaction with a companion reignites nuclear fusion in a carbon-oxygen white dwarf, causing a thermonuclear runaway, a catastrophic gain in pressure, and the disintegration of the whole white dwarf. It is usually thought that fusion is reignited in near-pycnonuclear conditions when the white dwarf approaches the Chandrasekhar mass. I briefly describe two long-standing problems faced by this scenario, and our suggestion that these supernovae instead resul...

Incidence of 'Candidatus Liberibacter asiaticus'-Infected Plants Among Citrandarins as Rootstock and Scion Under Field Conditions.

Science.gov (United States)

Boava, Leonardo Pires; Sagawa, Cíntia Helena Duarte; Cristofani-Yaly, Mariângela; Machado, Marcos Antonio

2015-04-01

Huanglongbing (HLB), caused by the bacterium 'Candidatus Liberibacter' spp., is currently one of the most serious diseases of citrus plants and has caused substantial economic losses. Thus far, there is no source of genetic resistance to HLB in the genus Citrus or its relatives. However, several studies have reported Poncirus trifoliata and some of its hybrids to be more tolerant to the disease. The main objective of this study was to report differences in the incidence of 'Ca. L. asiaticus' infection in citrandarin plants, hybrids from Sunki mandarin (Citrus sunki (Hayata) hort. ex Tanaka), and trifoliate orange Rubidoux (P. trifoliata (L.) Raf.)), after conducting an extensive survey under field conditions. These hybrid plants were established for approximately 7 years in an area with a high incidence of 'Ca. L. asiaticus'-infected plants. We selected two experimental areas (area A and area B), located approximately 10 m apart. Area A consists of Pera sweet orange (C. sinensis (L.) Osb.) grafted onto 56 different citrandarin rootstocks. Area B consists of citrandarin scions grafted onto Rangpur lime (C. limonia Osb.) rootstock. Bacteria in the leaves and roots were detected using real-time quantitative polymerase chain reaction. The incidence of 'Ca. L. asiaticus'-infected plants was 92% in area A and 14% in area B. Because infected plants occurred in both areas, we examined whether the P. trifoliata hybrid rootstock influenced HLB development and also determined the distribution of 'Ca. L. asiaticus' in Citrus tree tissues. Although this survey does not present evidence regarding the resistance of P. trifoliata and its hybrids in relation to bacteria or psyllids, future investigation, mainly using the most promising hybrids for response to 'Ca. L. asiaticus', will help us to understand the probable mechanism of defense or identifying compounds in P. trifoliata and its hybrids that are very important as strategy to combat HLB. Details of these results are

Rare White dwarf stars with carbon atmospheres

OpenAIRE

Dufour, P.; Liebert, James; Fontaine, G.; Behara, N.

2007-01-01

White dwarfs represent the endpoint of stellar evolution for stars with initial masses between approximately 0.07 msun and 8-10 msun, where msun is the mass of the Sun (more massive stars end their life as either black holes or neutron stars). The theory of stellar evolution predicts that the majority of white dwarfs have a core made of carbon and oxygen, which itself is surrounded by a helium layer and, for ~80 per cent of known white dwarfs, by an additional hydrogen layer. All white dwarfs...

Pulsating White Dwarfs in Cataclysmic Variables: The Marriage of ZZ Cet and Dwarf Nova

OpenAIRE

Warner, Brian; Woudt, Patrick A.

2003-01-01

There are now four dwarf novae known with white dwarf primaries that show large amplitude non-radial oscillations of the kind seen in ZZ Cet stars. We compare the properties of these stars and point out that by the end of the Sloan Digital Sky Survey more than 30 should be known.

Effects of some humidity and IBA hormone dose applicatýons on ...

African Journals Online (AJOL)

In this study, softwood cuttings were taken from M9 dwarf apple rootstocks in early June. Different indole-3-butyric acid (IBA) concentrations [0 (control), 500, 1500, 2500 and 3500 ppm], different air humidity levels (85 - 90%, 95-100%) and rooting media of perlite effects on rooting capability and root formation of M9 apple ...

Teste de porta-enxertos intergenéricos para marmeleiros em condições de viveiro Tests of intergeneric rootstocks for quinces in nursery conditions

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Rafael Pio

2009-04-01

Full Text Available Os marmeleiros sempre foram propagados comercialmente mediante o enraizamento de estacas. Devido ao baixo vigor das mudas, principalmente nos primeiros anos após o plantio, alguns trabalhos foram desenvolvidos no Brasil a fim de viabilizar a utilização do marmeleiro 'Japonês' (Chaenomeles sinensis Koehne como porta-enxerto para marmelos. Os resultados foram satisfatórios, mas frente à falta de outras opções de porta-enxertos mais vigorosos para marmeleiros e devido a observações em viveiro e a campo do alto vigor dos porta-enxertos para pereira 'Taiwan Nashi-C' (Pyrus calleryana Decne e 'Taiwan Mamenashi' (Pyrus betulifolia Bunge, objetivou-se, neste trabalho, verificar o crescimento de cultivares de marmeleiros ('Provence', 'Mendoza Inta-37', 'Portugal', 'Smyrna' e 'Japonês' enxertados sobre esses porta-enxertos, na fase de viveiro. Os marmeleiros foram enxertados pelo método de garfagem em mudas dos porta-enxertos 'Japonês', 'Taiwan Nashi-C' e 'Taiwan Mamenashi', mantidas em sacos plásticos (capacidade de 3 L de substrato, no período hibernal. Foram utilizados garfos com três gemas, coletadas de plantas-matrizes do Instituto Agronômico (IAC. O experimento foi realizado em viveiro telado (50% de luminosidade, sendo avaliados o comprimento e diâmetro do enxerto aos 60, 90, 120 e 150 dias após a realização da enxertia e a porcentagem de garfos brotados na última avaliação. Os porta-enxertos orientais de pereira apresentaram bons resultados na fase de viveiro, com 'Taiwan Nashi-C' destacando-se como porta-enxerto para os marmeleiros 'Smyrna' e 'Mendoza Inta-37', 'Taiwan Mamenashi' para o marmeleiro 'Smyrna' e 'Japonês' para o mesmo.The quince tree has always been commercially propagated by cuttings. Due to the low vigor, mainly in the first years of the orchard, a series of works was developed in Brazil in order to enable the use of the Japanese quince tree (Chaenomeles sinensis Koehne as a rootstock. The results were

Mutational Profiling Can Establish Clonal or Independent Origin in Synchronous Bilateral Breast and Other Tumors.

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Lei Bao

Full Text Available Synchronous tumors can be independent primary tumors or a primary-metastatic (clonal pair, which may have clinical implications. Mutational profiling of tumor DNA is increasingly common in the clinic. We investigated whether mutational profiling can distinguish independent from clonal tumors in breast and other cancers, using a carefully defined test based on the Clonal Likelihood Score (CLS = 100 x # shared high confidence (HC mutations/ # total HC mutations.Statistical properties of a formal test using the CLS were investigated. A high CLS is evidence in favor of clonality; the test is implemented as a one-sided binomial test of proportions. Test parameters were empirically determined using 16,422 independent breast tumor pairs and 15 primary-metastatic tumor pairs from 10 cancer types using The Cancer Genome Atlas.We validated performance of the test with its established parameters, using five published data sets comprising 15,758 known independent tumor pairs (maximum CLS = 4.1%, minimum p-value = 0.48 and 283 known tumor clonal pairs (minimum CLS 13%, maximum p-value 0.99, supporting independence. A plausible molecular mechanism for the shift from hormone receptor positive to triple negative was identified in the clonal pair.We have developed the statistical properties of a carefully defined Clonal Likelihood Score test from mutational profiling of tumor DNA. Under identified conditions, the test appears to reliably distinguish between synchronous tumors of clonal and of independent origin in several cancer types. This approach may have scientific and clinical utility.

Plant Clonal Integration Mediates the Horizontal Redistribution of Soil Resources, Benefiting Neighboring Plants.

Science.gov (United States)

Ye, Xue-Hua; Zhang, Ya-Lin; Liu, Zhi-Lan; Gao, Shu-Qin; Song, Yao-Bin; Liu, Feng-Hong; Dong, Ming

2016-01-01

Resources such as water taken up by plants can be released into soils through hydraulic redistribution and can also be translocated by clonal integration within a plant clonal network. We hypothesized that the resources from one (donor) microsite could be translocated within a clonal network, released into different (recipient) microsites and subsequently used by neighbor plants in the recipient microsite. To test these hypotheses, we conducted two experiments in which connected and disconnected ramet pairs of Potentilla anserina were grown under both homogeneous and heterogeneous water regimes, with seedlings of Artemisia ordosica as neighbors. The isotopes [(15)N] and deuterium were used to trace the translocation of nitrogen and water, respectively, within the clonal network. The water and nitrogen taken up by P. anserina ramets in the donor microsite were translocated into the connected ramets in the recipient microsites. Most notably, portions of the translocated water and nitrogen were released into the recipient microsite and were used by the neighboring A. ordosica, which increased growth of the neighboring A. ordosica significantly. Therefore, our hypotheses were supported, and plant clonal integration mediated the horizontal hydraulic redistribution of resources, thus benefiting neighboring plants. Such a plant clonal integration-mediated resource redistribution in horizontal space may have substantial effects on the interspecific relations and composition of the community and consequently on ecosystem processes.

Plant clonal integration mediates the horizontal redistribution of soil resources, benefiting neighbouring plants

Directory of Open Access Journals (Sweden)

Xuehua eYe

2016-02-01

Full Text Available Resources such as water taken up by plants can be released into soils through hydraulic redistribution and can also be translocated by clonal integration within a plant clonal network. We hypothesized that the resources from one (donor microsite could be translocated within a clonal network, released into different (recipient microsites and subsequently used by neighbour plants in the recipient microsite. To test these hypotheses, we conducted two experiments in which connected and disconnected ramet pairs of Potentilla anserina were grown under both homogeneous and heterogeneous water regimes, with seedlings of Artemisia ordosica as neighbours. The isotopes [15N] and deuterium were used to trace the translocation of nitrogen and water, respectively, within the clonal network. The water and nitrogen taken up by P. anserina ramets in the donor microsite were translocated into the connected ramets in the recipient microsites. Most notably, portions of the translocated water and nitrogen were released into the recipient microsite and were used by the neighbouring A. ordosica, which increased growth of the neighbouring A. ordosica significantly. Therefore, our hypotheses were supported, and plant clonal integration mediated the horizontal hydraulic redistribution of resources, thus benefiting neighbouring plants. Such a plant clonal integration-mediated resource redistribution in horizontal space may have substantial effects on the interspecific relations and composition of the community and consequently on ecosystem processes.

Pulsations in carbon-atmosphere white dwarfs: A new chapter in white dwarf asteroseismology

International Nuclear Information System (INIS)

Fontaine, G; Brassard, P; Dufour, P; Green, E M; Liebert, J

2009-01-01

We present some of the results of a survey aimed at exploring the asteroseismological potential of the newly-discovered carbon-atmosphere white dwarfs. We show that, in certains regions of parameter space, carbon-atmosphere white dwarfs may drive low-order gravity modes. We demonstrate that our theoretical results are consistent with the recent exciting discovery of luminosity variations in SDSS J1426+5752 and some null results obtained by a team of scientists at McDonald Observatory. We also present follow-up photometric observations carried out by ourselves at the Mount Bigelow 1.6-m telescope using the new Mont4K camera. The results of follow-up spectroscopic observations at the MMT are also briefly reported, including the surprising discovery that SDSS J1426+5752 is not only a pulsating star but that it is also a magnetic white dwarf with a surface field near 1.2 MG. The discovery of g-mode pulsations in SDSS J1426+5752 is quite significant in itself as it opens a fourth asteroseismological 'window', after the GW Vir, V777 Her, and ZZ Ceti families, through which one may study white dwarfs.

Root-to-shoot hormonal communication in contrasting rootstocks suggests an important role for the ethylene precursor aminocyclopropane-1-carboxylic acid in mediating plant growth under low-potassium nutrition in tomato

Directory of Open Access Journals (Sweden)

Cristina Martínez-Andújar

2016-11-01

Full Text Available Selection and breeding of rootstocks that can tolerate low K supply may increase crop productivity in low fertility soils and reduce fertilizer application. However, the underlying physiological traits are still largely unknown. In this study, 16 contrasting recombinant inbred lines (RILs derived from a cross between domestic and wild tomato species (Solanum lycopersicum x S. pimpinellifolium have been used to analyse traits related to the rootstock-mediated induction of low (L, low shoot fresh weight or high (H, high shoot fresh weight vigour to a commercial F1 hybrid grown under control (6 mM, c and low-K (1mM, k. Based on hormonal and ionomic composition in the root xylem sap and the leaf nutritional status after long-term (7 weeks exposure low-K supply, a model can be proposed to explain the rootstocks effects on shoot performance with the ethylene precursor aminocyclopropane-1-carboxylic acid (ACC playing a pivotal negative role. The concentration of this hormone was higher in the low-vigour Lc and Lk rootstocks under both conditions, increased in the sensitive HcLk plants under low-K while it was reduced in the high-vigour Hk ones. Low ACC levels would promote the transport of K vs Na in the vigorous Hk grafted plants. Along with K, Ca and S, micronutrient uptake and transport were also activated in the tolerant Hk combinations under low-K. Additionally, an interconversion of trans-zeatin into trans-zeatin riboside would contribute to decrease ACC in the tolerant LcHk plants. The high vigour induced by the Hk plants can also be explained by an interaction of ACC with other hormones (cytokinins and salicylic, abscisic and jasmonic acids. Therefore, Hk rootstocks convert an elite tomato F1 cultivar into a (micro nutrient-efficient phenotype, improving growth under reduced K fertilization.

The RSA survey of dwarf galaxies, 1: Optical photometry

Science.gov (United States)

Vader, J. Patricia; Chaboyer, Brian

1994-01-01

We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are

Virulence, sporulation, and elicitin production in three clonal lineages of Phytophthora ramorum

Science.gov (United States)

Phytophthora ramorum populations are clonal and consist of three lineages. Recent studies have shown that the clonal lineages may have varying degrees of aggressiveness on some host species, such as Quercus rubra. In this study, we examined virulence, sporulation and elicitin production of five P. ...

Novel Prunus rootstock somaclonal variants with divergent ability to tolerate waterlogging.

Science.gov (United States)

Pistelli, Laura; Iacona, Calogero; Miano, Dario; Cirilli, Marco; Colao, Maria Chiara; Mensuali-Sodi, Anna; Muleo, Rosario

2012-03-01

Plants require access to free water for nutrient uptake, but excess water surrounding the roots can be injurious or even lethal because it blocks the transfer of free oxygen between the soil and the atmosphere. Genetic improvement efforts in this study were focused on the increased tolerance in roots to waterlogging. Among a pool of clones generated in vitro from leaf explants of rootstock Mr.S.2/5 of Prunus cerasifera L., the S.4 clone was flood tolerant whereas the S.1 clone was sensitive. The S.4 clone formed adventitious roots on exposure to flooding. Moreover, the chlorophyll content and mitochondrial activity in the leaf and root, soluble sugar content, alcohol dehydrogenase activity and ethylene content were different between the clones. The sorbitol transporter gene (SOT1) was up-regulated during hypoxia, the alcohol dehydrogenase genes (ADH1 and ADH3) were up-regulated in the leaves and down-regulated in the roots of the S.4 clone during hypoxia, and the 1-aminocyclopropane-1-oxidase gene (ACO1) was up-regulated in the leaves and roots of the S.4 clone during hypoxia and down-regulated in the wild-type roots. In addition, in the S.4 root, hypoxia induced significant down-regulation of a glycosyltransferase-like gene (GTL), which has a yet-undefined role. Although the relevant variation in the S.4 genome has yet to be determined, genetic alteration clearly conferred a flooding-tolerant phenotype. The isolation of novel somaclonals with the same genomic background but with divergent tolerance to flooding may offer new insights in the elucidation of the genetic machinery of resistance to flooding and aid in the selection of new Prunus rootstocks to be used in various adverse environments.

Clonal growth and plant species abundance

Czech Academy of Sciences Publication Activity Database

Herben, Tomáš; Nováková, Z.; Klimešová, Jitka

2014-01-01

Roč. 114, č. 2 (2014), s. 377-388 ISSN 0305-7364 R&D Projects: GA ČR GA526/09/0963 Institutional support: RVO:67985939 Keywords : clonal plants * frequency * plant communities of Central Europe Subject RIV: EF - Botanics Impact factor: 3.654, year: 2014

The WFCAM transit survey and cool white dwarfs

Directory of Open Access Journals (Sweden)

Pinfield D.

2013-04-01

Full Text Available We present results from our search for cool white dwarfs in the WTS (WFCAM Transit Survey. Repeat observations starting in 2007 allowed to produce deep stacked images in J and measure proper motions. We combine this with deep optical imaging to select cool white dwarf candidates (Teff < 5000 K. About 27 cool white dwarf candidates with proper motions above 0.10 arcsec/yr were identified in one of the fields representing 1/8th of the survey area. Follow-up spectroscopy with the 10.2 m GTC telescope at La Palma confirmed the white dwarf status for all observed candidates. On-going work is being carried out to increase the sample of cool white dwarfs that will allow a more comprehensive study of the thick disk/halo white dwarf population.

Production and evaluation of dwarf and semi-dwarf winter wheat mutants

International Nuclear Information System (INIS)

Barabas, Z.; Kertesz, Z.

1984-01-01

A special research programme for evolving and evaluating dwarf wheat forms resistant to lodging was carried out at the Cereal Research Institute, Wheat Division, Szeged, Hungary. Seed lots of the two tall winter wheat varieties Jubilejnaya 50 and Partizanka were exposed to gamma ray of 60 Co. With irradiation of 15000 rad 60 Co all of M 1 plants grown in the field were almost totally destroyed in 1980 and about 50% in 1982. In the greenhouse the number of lost M 1 plants was insignificant. Only a small number of plants died both in the greenhouse and in the field when they were irradiated with 5000 rad. A treatment with this lower dose of irradiation probably may help the breeders in selection for winter hardiness. 97 dwarf wheat lines already established were analysed for height character by a top cross method using the variety Jubilejnaya 50 as a tester. Height data of the simultaneously grown parental as well as the F 1 and F 2 offsprings indicated that the majority of them were recessive, except 3 cases where dominant or semi-dominant dwarfism was observed. Noteworthy is the Mx 158 a new semi-dwarf variety candidate, 60-65 cm in height at normal stand and resistant to all the main diseases here (powdery mildew and rusts). Its grain and protein production per unit area is also very good. Some genetically lesser-known dwarf sources were investigated in a complete crossing diallel test. (author)

WISE Y dwarfs as probes of the brown dwarf-exoplanet connection

International Nuclear Information System (INIS)

Beichman, C.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Cushing, Michael C.; Dodson-Robinson, Sally; Marley, Mark S.; Morley, Caroline V.; Wright, E. L.

2014-01-01

We have determined astrometric positions for 15 WISE-discovered late-type brown dwarfs (six T8-9 and nine Y dwarfs) using the Keck-II telescope, the Spitzer Space Telescope, and the Hubble Space Telescope. Combining data from 8 to 20 epochs we derive parallactic and proper motions for these objects, which puts the majority within 15 pc. For ages greater than a few Gyr, as suggested from kinematic considerations, we find masses of 10-30 M Jup based on standard models for the evolution of low-mass objects with a range of mass estimates for individual objects, depending on the model in question. Three of the coolest objects have effective temperatures ∼350 K and inferred masses of 10-15 M Jup . Our parallactic distances confirm earlier photometric estimates and direct measurements and suggest that the number of objects with masses below about 15 M Jup must be flat or declining, relative to higher mass objects. The masses of the coldest Y dwarfs may be similar to those inferred for recently imaged planet-mass companions to nearby young stars. Objects in this mass range, which appear to be rare in both the interstellar and protoplanetary environments, may both have formed via gravitational fragmentation—the brown dwarfs in interstellar clouds and companion objects in a protoplanetary disk. In both cases, however, the fact that objects in this mass range are relatively infrequent suggests that this mechanism must be inefficient in both environments.

Morphology and Structures of Nearby Dwarf Galaxies

Science.gov (United States)

Seo, Mira; Ann, HongBae

2015-08-01

We performed an analysis of the structure of nearby dwarf galaxies based on a 2-dimensional decomposition of galaxy images using GALFIT. The present sample consists of ~1,100 dwarf galaxies with redshift less than z = 0.01, which is is derived from the morphology catalog of the Visually classified galaxies in the local universe (Ann, Seo, and Ha 2015). In this catalog, dwarf galaxies are divided into 5 subtypes: dS0, dE, dSph, dEbc, dEblue with distinction of the presence of nucleation in dE, dSph, and dS0. We found that dSph and dEblue galaxies are fainter than other subtypes of dwarf galaxies. In most cases, single component, represented by the Sersic profile with n=1~1.5, well describes the luminosity distribution of dwarf galaxies in the present sample. However, a significant fraction of dS0, dEbc, and dEbue galaxies show sub-structures such as spiral arms and rings. We will discuss the morphology dependent evolutionary history of the local dwarf galaxies.

High-dispersion observations of H-alpha in the suspected brown dwarf, white dwarf binary system G29-38

International Nuclear Information System (INIS)

Liebert, J.; Saffer, R.A.; Pilachowski, C.A.

1989-01-01

High-dispersion spectroscopy of the H-alpha absorption line of the cool DA white dwarf G29-38 is reported. This is the star for which a recently detected IR excess has been suggested to be due to a possible brown dwarf companion. Three echelle spectra show no evidence for radial-velocity variations larger than about 1.1 + or - 8.7 km/s and are used to derive a weighted heliocentric radial velocity of 33.7 + or - 4.3 kms/s for the white dwarf. The observations of a sharp absorption-line core restricts the possible rotation of the white dwarf to 40 km/s or less and ensures that any surface magnetic field has a strength of 100,000 G or less. These results make it unlikely that the DA white dwarf has previously been in a cataclysmic variable accretion phase. 18 references

HOW TO MAKE AN ULTRA-FAINT DWARF SPHEROIDAL GALAXY: TIDAL STIRRING OF DISKY DWARFS WITH SHALLOW DARK MATTER DENSITY PROFILES

International Nuclear Information System (INIS)

Łokas, Ewa L.; Kazantzidis, Stelios; Mayer, Lucio

2012-01-01

In recent years the Sloan Digital Sky Survey has unraveled a new population of ultra-faint dwarf galaxies (UFDs) whose origin remains a puzzle in the vicinity of the Milky Way (MW). Using a suite of collisionless N-body simulations, we investigate the formation of UFDs in the context of the tidal stirring model for the formation of dwarf spheroidal galaxies in the Local Group (LG). Our simulations are designed to reproduce the tidal interactions between MW-sized host galaxies and rotationally supported dwarfs embedded in 10 9 M ☉ dark matter (DM) halos. We explore a variety of inner density slopes ρ∝r –α for the dwarf DM halos, ranging from core-like (α = 0.2) to cuspy (α = 1), and different dwarf orbital configurations. Our experiments demonstrate that UFDs can be produced via tidal stirring of disky dwarfs on relatively tight orbits, consistent with a redshift of accretion by the host galaxy of z ∼ 1, and with intermediate values for the halo inner density slopes (ρ∝r –0.6 ). The inferred slopes are in excellent agreement with those resulting from both the modeling of the rotation curves of dwarf galaxies and recent cosmological simulations of dwarf galaxy formation. Comparing the properties of observed UFDs with those of their simulated counterparts, we find remarkable similarities in terms of basic observational parameters. We conclude that tidal stirring of rotationally supported dwarfs represents a viable mechanism for the formation of UFDs in the LG environment.

Clonal neoantigens elicit T cell immunoreactivity and sensitivity to immune checkpoint blockade

DEFF Research Database (Denmark)

McGranahan, Nicholas; Furness, Andrew J S; Rosenthal, Rachel

2016-01-01

demonstrate a relationship between clonal neoantigen burden and overall survival in primary lung adenocarcinomas. CD8(+)tumor-infiltrating lymphocytes reactive to clonal neoantigens were identified in early-stage non-small cell lung cancer and expressed high levels of PD-1. Sensitivity to PD-1 and CTLA-4...

Clonal relation in a case of CLL, ALCL, and Hodgkin composite lymphoma

NARCIS (Netherlands)

van den Berg, Anke; Maggio, Ewerton; Rust, R; Kooistra, K; Diepstra, A; Poppema, S

2002-01-01

Large cell lymphomas and Hodgkin disease may develop during the course of chronic lymphocytic leukemia (CLL). In some cases the transformed cells are Epstein-Barr virus (EBV)-positive and not clonally related to the CLL cells. In other cases the transformed cells have the same clonal rearrangements

Enhanced salt resistance in apple plants overexpressing a Malus vacuolar Na+/H+ antiporter gene is associated with differences in stomatal behavior and photosynthesis.

Science.gov (United States)

Li, Chao; Wei, Zhiwei; Liang, Dong; Zhou, Shasha; Li, Yonghong; Liu, Changhai; Ma, Fengwang

2013-09-01

High salinity is a major abiotic factor that limits crop production. The dwarfing apple rootstock M.26 is sensitive to such stress. To obtain an apple that is adaptable to saline soils, we transformed this rootstock with a vacuolar Na(+)/H(+) antiporter, MdNHX1. Differences in salt tolerance between transgenic and wild-type (WT) rootstocks were examined under field conditions. We also compared differences when 'Naganofuji No. 2' apple was grafted onto these transgenic or WT rootstocks. Plants on the transgenic rootstocks grew well during 60 d of mild stress (100 mM NaCl) while the WT exhibited chlorosis, inhibited growth and even death. Compared with the untreated control, the stomatal density was greater in both non-grafted and grafted WT plants exposed to 200 mM NaCl. In contrast, that density was significantly decreased in leaves from grafted transgenic plants. At 200 mM NaCl, net photosynthesis, stomatal conductance, intercellular CO2 concentration, and chlorophyll contents were markedly reduced in the WT, whereas the declines in those values were only minor in similarly stressed transgenic plants. Therefore, we conclude that overexpressing plants utilize a better protective mechanism for retaining higher photosynthetic capacity. Furthermore, this contrast in tolerance and adaptability to stress is linked to differences in stomatal behavior and photosynthetic rates. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Progenitors of white dwarfs

International Nuclear Information System (INIS)

Drilling, J.S.; Schoenberner, D.

1985-01-01

Direct observational evidence is presented which indicates that the immediate progenitors of white dwarfs are the central stars of planetary nebulae (approximately 70%), other post-AGB objects (approximately 30%), and post-HB objects not massive enough to climb the AGB (approximately 0.3%). The combined birth rate for these objects is in satisfactory agreement with the death rate of main-sequence stars and the birth rate of white dwarfs

Explosive helium burning in white dwarf stars

Energy Technology Data Exchange (ETDEWEB)

Khokhlov, A.M. (AN SSSR, Moscow. Astronomicheskij Sovet)

1984-04-01

Helium burning kinetics in white dwarfs has been considered at constant temperatures T >= 10/sup 9/ K and densities rho >10/sup 5/ g/cm/sup 3/. It is found, that helium detonation in white dwarfs does not lead to formation of light (A < 56) elements. Thus, helium white dwarf model for supernova 1 is inconsistent with observations.

Project DWARF - using eclipsing binaries for searching for exoplanets and brown dwarfs

Science.gov (United States)

Kudak, V.; Parimucha, Š.

2016-12-01

Project DWARF is a long-term observation campaign for about 60 selected eclipsing binaries aimed for detection of exoplanets or other objects (brown dwarfs) in low-mass detached binaries of different types (low-mass eclipsing binaries with M and K components, short-period binaries with sdB or sdO component, post-common-envelope systems containing a white dwarf). Existence of other bodies in systems are determined by analysing of O-C diagrams, constructed from observed minima times of binaries. Objects are selected with intention to determine minima with high precision. About 40 observatories are involved into the network at present time, mostly situated in Europe. The observations are made by small or middle class telescopes with apertures of 20-200 cm. In this contribution we give information about current status of the project, we present main goals and results of 4 years observations.

A Survey for Hα Emission from Late L Dwarfs and T Dwarfs

Science.gov (United States)

Pineda, J. Sebastian; Hallinan, Gregg; Kirkpatrick, J. Davy; Cotter, Garret; Kao, Melodie M.; Mooley, Kunal

2016-07-01

Recently, studies of brown dwarfs have demonstrated that they possess strong magnetic fields and have the potential to produce radio and optical auroral emissions powered by magnetospheric currents. This emission provides the only window on magnetic fields in the coolest brown dwarfs and identifying additional benchmark objects is key to constraining dynamo theory in this regime. To this end, we conducted a new red optical (6300-9700 Å) survey with the Keck telescopes looking for Hα emission from a sample of late L dwarfs and T dwarfs. Our survey gathered optical spectra for 29 targets, 18 of which did not have previous optical spectra in the literature, greatly expanding the number of moderate-resolution (R ˜ 2000) spectra available at these spectral types. Combining our sample with previous surveys, we confirm an Hα detection rate of 9.2±{}2.13.5% for L and T dwarfs in the optical spectral range of L4-T8. This detection rate is consistent with the recently measured detection rate for auroral radio emission from Kao et al., suggesting that geometrical selection effects due to the beaming of the radio emission are small or absent. We also provide the first detection of Hα emission from 2MASS 0036+1821, previously notable as the only electron cyclotron maser radio source without a confirmed detection of Hα emission. Finally, we also establish optical standards for spectral types T3 and T4, filling in the previous gap between T2 and T5. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Polarized radiation in magnetic white dwarfs

International Nuclear Information System (INIS)

Rosi, L.A.; Zimmerman, R.L.; Kemp, J.C.

1976-01-01

A model for magnetic white dwarfs is proposed which attributes the partially polarized light to synchrotron radiation. The source of the radiation is relativistic electrons trapped in the magnetosphere of a white dwarf. The white dwarf's magnetic field is assumed to be dipolar. The Stokes parameters for the synchrotron radiation are tabulated as a function of frequency, observer's orientation, and energy and spatial distribution of the relativistic electrons. The results of the synchrotron calculations are applied to the polarization observations of Grw+70degree8247 and DQ Herculis. This model can account for the major features of the polarized radiation coming from these two magnetic white dwarfs. The calculations predict for Grw+70degree8247 that the surface magnetic field is B/sub s/approximately-less-than4 x 10 6 gauss, that the incident viewing angle is 45degreeapproximately-less-thantheta 0 approximately-less-than75degree, and that the electrons are trapped with nearly an isotropic distribution about the white dwarf. For DQ Herculis the surface magnetic field is B/sub s/approximately-less-than7 x 10 6 gauss and the trapped electrons are confined to a dislike region about the white dwarf. For both cases the density of electrons in the magnetosphere falls in the range of 10 5 approximately-less-thannapproximately-less-than10 7 cm -3 with energies of about 4--35 MeV

EVOLUTIONARY TRACKS OF TIDALLY STIRRED DISKY DWARF GALAXIES

International Nuclear Information System (INIS)

Lokas, Ewa L.; Kazantzidis, Stelios; Mayer, Lucio

2011-01-01

Using collisionless N-body simulations, we investigate the tidal evolution of late-type, rotationally supported dwarfs inside Milky Way sized host galaxies. Our study focuses on a wide variety of dwarf orbital configurations and initial structures. During the evolution, the disky dwarfs undergo strong mass loss, the stellar disks are transformed into spheroids, and rotation is replaced by random motions of the stars. Thus, the late-type progenitors are transformed into early-type dwarfs as envisioned by the tidal stirring model for the formation of dwarf spheroidal (dSph) galaxies in the Local Group. We determine the photometric properties of the dwarfs, including the total visual magnitude, the half-light radius, and the central surface brightness as they would be measured by an observer near the galactic center. Special emphasis is also placed on studying their kinematics and shapes. We demonstrate that the measured values are biased by a number of observational effects including the increasing angle of the observation cone near the orbital pericenter, the fact that away from the pericenter the tidal tails are typically oriented along the line of sight, and the fact that for most of the evolution the stellar components of the dwarfs are triaxial ellipsoids whose major axis tumbles with respect to the line of sight. Finally, we compare the measured properties of the simulated dwarfs to those of dwarf galaxies in the Local Group. The evolutionary tracks of the dwarfs in different parameter planes and the correlations between their different properties, especially the total magnitude and the surface brightness, strongly suggest that present-day dSph galaxies may have indeed formed from late-type progenitors as proposed by the tidal stirring scenario.

Transgenerational plasticity in clonal plants

Czech Academy of Sciences Publication Activity Database

Latzel, Vít; Klimešová, Jitka

2010-01-01

Roč. 24, č. 6 (2010), s. 1537-1543 ISSN 0269-7653 R&D Projects: GA ČR GD206/08/H044; GA ČR GA526/09/0963; GA ČR GPP505/10/P173 Institutional research plan: CEZ:AV0Z60050516 Keywords : maternal effect * evolution * clonal plants Subject RIV: EF - Botanics Impact factor: 2.398, year: 2010

A DARK SPOT ON A MASSIVE WHITE DWARF

Energy Technology Data Exchange (ETDEWEB)

Kilic, Mukremin; Gianninas, Alexandros; Curd, Brandon; Wisniewski, John P. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States); Bell, Keaton J.; Winget, D. E.; Winget, K. I. [Department of Astronomy, University of Texas at Austin, Austin, TX 78712 (United States); Brown, Warren R. [Smithsonian Astrophysical Observatory, 60 Garden St., Cambridge, MA 02138 (United States); Hermes, J. J. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Dufour, Patrick [Institut de recherche sur les exoplanétes (iREx), Département de Physique, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7 (Canada)

2015-12-01

We present the serendipitous discovery of eclipse-like events around the massive white dwarf SDSS J152934.98+292801.9 (hereafter J1529+2928). We selected J1529+2928 for time-series photometry based on its spectroscopic temperature and surface gravity, which place it near the ZZ Ceti instability strip. Instead of pulsations, we detect photometric dips from this white dwarf every 38 minutes. Follow-up optical spectroscopy observations with Gemini reveal no significant radial velocity variations, ruling out stellar and brown dwarf companions. A disintegrating planet around this white dwarf cannot explain the observed light curves in different filters. Given the short period, the source of the photometric dips must be a dark spot that comes into view every 38 minutes due to the rotation of the white dwarf. Our optical spectroscopy does not show any evidence of Zeeman splitting of the Balmer lines, limiting the magnetic field strength to B < 70 kG. Since up to 15% of white dwarfs display kG magnetic fields, such eclipse-like events should be common around white dwarfs. We discuss the potential implications of this discovery on transient surveys targeting white dwarfs, like the K2 mission and the Large Synoptic Survey Telescope.

Effects of magnetic fields in white dwarfs

International Nuclear Information System (INIS)

Franzon, Bruno; Schramm, Stefan

2017-01-01

We perform calculations of white dwarfs endowed with strong magnetic fields. White dwarfs are the progenitors of supernova Type Ia explosions and they are widely used as candles to show that the Universe is expanding and accelerating. However, observations of ultraluminous supernovae have suggested that the progenitor of such an explosion should be a white dwarf with mass above the well-known Chandrasekhar limit ∼ 1.4 M⊙. In corroboration with other works, but by using a fully general relativistic framework, we obtained also strongly magnetized white dwarfs with masses M ∼ 2.0 M⊙. (paper)

Genetic identification of a dwarf mutant in cucumber ( Cucumis ...

African Journals Online (AJOL)

The dwarf (compact) plant architecture is an important trait in cucumber (Cucumis sativus L.) breeding. A dwarf type mutant was selected from the cucumbers. The morphological and reproductive characteristics of the dwarf were compared with the vine plants. The dwarf type of cucumbers is characterized by its short ...

Comportamento agronômico inicial da cv. Chimarrita enxertada em cinco porta-enxertos de pessegueiro Agronomical behavior of cv. Chimarrita on five rootstocks of peach trees

Directory of Open Access Journals (Sweden)

Moacir da Silva Rocha

2007-01-01

Full Text Available O trabalho teve por objetivo avaliar a resposta agronômica da cv. Chimarrita enxertada em cinco porta-enxertos, nas condições edafoclimáticas da região de Pelotas-RS, no período de 2003 a 2005. Durante o período de execução do experimento, foram avaliados o diâmetro do tronco do porta-enxerto e da cultivar-copa, comprimento médio dos ramos principais, volume de copa, massa fresca e massa seca do material vegetal retirado nas podas verde e de inverno, índice de intensidade de poda, massa média dos frutos, produção por planta, eficiência produtiva, produção por hectare, sólidos solúveis totais, firmeza da polpa, diâmetro e coloração dos frutos. O porta-enxerto 'Capdeboscq' induziu o maior crescimento vegetativo na cv. Chimarrita durante os três anos de avaliação, seguido do porta-enxerto 'Okinawa'. Este, por sua vez, induziu o maior rendimento produtivo (1,65 t ha-1. A cv. Capdeboscq proporcionou a obtenção de frutos com maior massa. Os porta-enxertos 'GF 305' e 'Aldrighi' induziram menor desenvolvimento vegetativo e a mais baixa produtividade (0,52 t.ha-1 .The objective for this study was to evaluate the agronomical behavior of cv. Chimarrita on five rootstocks of peach trees in Pelotas- RS from 2003 to 2005. The variables evaluated were: trunk diameters of the rootstock and of the scion; length of the annual terminal growth; volume of the canopy; fresh and dry weight of the material taken by the summer and winter pruning; pruning intensity index; fruit weight; fruit production per tree; production efficiency; productivity per hectare; total soluble solids; pulp firmness; and fruit diameter and color. It was observed that the trees from: rootstock 'Capdeboscq' promoted higher vegetative growth and larger fruits, followed by the ones from the rootstock 'Okinawa' which promoted the highest yield (1, 65 t.ha-1; the rootstock 'GF 305' and 'Aldrighi' had the lowest vegetative development and yield (0, 52 t.ha-1.

Evaluation of Relative Resistance in Thirty Dwarf Mahaleb Genotypes to Four Phytophthora Species in the Greenhouse and Garden

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mohammad hajian

2018-01-01

Full Text Available Introduction: The best cherry rootstock for Iranian nurseries and orchards is Prunus mahaleb (L. Mill. Mahaleb is tolerant to lime-induced iron chlorosis and zinc deficiency. It is a good rootstock on light, calcareous soils and arid climates in Iran but sensitive to Phytophthora. Iran represents a significant source of germplasm of different fruit species, especially for those from the genus Prunus. Collection and research on P.mahaleb was initiated at the Horticultural Department of Khorasan Razavi Agriculture and Natural Resources Research and Education Center in 1997 for mahaleb cherry rootstock. Some researchers have reported pathogenicity of Phytophthora species (Banihashemi and Sartipi, 2004; Wilcox and Mircetich, 1985; Exadaktylou and Thomidis, 2005; Tomidis et al., 2008. This study was conducted to evaluate the susceptibility of 30 selected dwarf Mahaleb genotypes to P.nicotianae, P.citricola, P.cactorum and P. citrophthora under greenhouse and orchard conditions. Material and methods: In this study, the response of 30 selected dwarf Mahaleb genotypes (188, 171, 165, 162, 161, 155, 139, 136, 131, 120, 106, 104, 101, 100, 90, 194, 195, 199, 200, 224, 228, 247 , 249, 265, 266, 267, 268, 270, 272, 277 to disease caused by four species of the fungus Phytophthora root and crown rot were investigated under greenhouse and orchard conditions. Greenhouse experiments were performed based on Ribeiro and Baumer, 1977 and modified it by Feichtenberger et al., 1984. For evaluation the index disease was performed based on the method of Broadbent and Gollnow 1992. Orchard terials was laid out in the Toragh research station in Mashhad. Evaluation of genotypes and contamination based on Tomidis, 2001 was performed by measuring the area of necrosis. Results and discussion: In evaluating the reaction of young seedling dwarf mahaleb genotypes to four Phytophthora species under greenhouse conditions, results showed that four species of Phytophthora pathogens

Clonal Growth Forms in Eastern Ladakh, Western Himalayas: Classification and Habitat Preferences

Czech Academy of Sciences Publication Activity Database

Klimešová, Jitka; Doležal, Jiří; Dvorský, Miroslav; de Bello, Francesco; Klimeš, Leoš

2011-01-01

Roč. 46, 2-3 (2011), 191-217 ISSN 1211-9520 R&D Projects: GA AV ČR IAA600050802 Institutional research plan: CEZ:AV0Z60050516 Keywords : Clonal growth form * Clonal space occupancy strategies * Habitat types Subject RIV: EF - Botanics Impact factor: 1.500, year: 2011

Microlensing Binaries with Candidate Brown Dwarf Companions

DEFF Research Database (Denmark)

Shin, I.-G; Han, C.; Gould, A.

2012-01-01

masses of the brown dwarf companions are 0.02 ± 0.01 M⊙ and 0.019 ± 0.002 M⊙ for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events...

Functional specialization of ramets in a clonal plant network functional specialization of ramets in a clonal plant network

NARCIS (Netherlands)

Ikegami, M.

2004-01-01

Functional specialization of ramets and co-operation between interconnected ramets in heterogeneous environments are studied in this thesis. Since clonal plants can spread horizontally by vegetative growth, a genet has the potential to grow across a heterogeneous environment. Therefore, ramets can

Inoculação micorrízica e aclimatização de dois porta-enxertos de macieira micropropagados Mycorrhizal inoculation and acclimatization of two micropropagated apple rootstocks

Directory of Open Access Journals (Sweden)

Lucir Maria Locatelli

2002-02-01

Full Text Available A micropropagação e a inoculação de fungos micorrízicos arbusculares (FMA podem melhorar a qualidade de mudas produzidas comercialmente. Essas técnicas permitem a produção de plantas homogêneas e de alta qualidade em curtos períodos de tempo, mas isso exige o conhecimento da interação entre fungos e plantas, substratos e técnicas de aclimatização e inoculação. Foi realizado um estudo em condições controladas a fim de desenvolver procedimentos para aclimatizar e inocular FMA nos porta-enxertos de macieira (Malus spp. Marubakaido, vigoroso e com forte sistema radicular, e M.9, nanizante e com sistema radicular pouco desenvolvido. Plantas oriundas de micropropagação foram imersas em ácido indolebutírico (5miM e transferidas para substrato à base de solo, a fim de serem enraizadas ex vitro. Antes ou após o enraizamento, inoculou-se uma mistura de isolados de Scutellospora pellucida, Glomus etunicatum e Glomus sp. A fase de enraizamento durou 21 dias, e após 51 e 81 dias avaliaram-se colonização micorrízica, altura, peso da matéria fresca e seca da parte aérea e relação entre raiz e parte aérea das plantas. A colonização micorrízica variou entre 50% e 70% para ambos porta-enxertos, tendo efeito positivo sobre o crescimento do porta-enxerto Marubakaido, enquanto o porta-enxerto M.9 teve seu desenvolvimento inibido pela presença dos FMA.The combination of micropropagation and inoculation with arbuscular mycorrhizal fungi (AMF can improve the quality of seedling plants produced on a commercial scale. These techniques allow high quality and homogeneous seedling production in a shorter period of time, but they require understanding of the interaction among fungi, plants, substrates, acclimatization and inoculation techniques. A study was performed under controlled conditions to develop procedures to acclimatize and inoculate AMF in two apple (Malus spp. rootstocks: vigorous strong-rooted Marubakaido and the dwarfing

Clonal diversity and estimation of relative clone age: application to agrobiodiversity of yam (Dioscorea rotundata).

Science.gov (United States)

Scarcelli, Nora; Couderc, Marie; Baco, Mohamed N; Egah, Janvier; Vigouroux, Yves

2013-11-13

Clonal propagation is a particular reproductive system found in both the plant and animal kingdoms, from human parasites to clonally propagated crops. Clonal diversity provides information about plant and animal evolutionary history, i.e. how clones spread, or the age of a particular clone. In plants, this could provide valuable information about agrobiodiversity dynamics and more broadly about the evolutionary history of a particular crop. We studied the evolutionary history of yam, Dioscorea rotundata. In Africa, Yam is cultivated by tuber clonal propagation. We used 12 microsatellite markers to identify intra-clonal diversity in yam varieties. We then used this diversity to assess the relative ages of clones. Using simulations, we assessed how Approximate Bayesian Computation could use clonal diversity to estimate the age of a clone depending on the size of the sample, the number of independent samples and the number of markers. We then applied this approach to our particular dataset and showed that the relative ages of varieties could be estimated, and that each variety could be ranked by age. We give a first estimation of clone age in an approximate Bayesian framework. However the precise estimation of clone age depends on the precision of the mutation rate. We provide useful information on agrobiodiversity dynamics and suggest recurrent creation of varietal diversity in a clonally propagated crop.

Development of compact mutants in apple and sour cherry

International Nuclear Information System (INIS)

Zagaja, S.W.; Przybyla, A.; Machnik, B.

1982-01-01

During the period 1973 - 79 studies were conducted with the aim of developing compact mutants in apple and cherry cultivars and in apple vegetative rootstocks. During the investigations the effect of the dose of gamma rays on frequency of the mutants was studied. Attempts were also made to evolve a micropropagation technique adapted to propagate P 2 and P 22 apple rootstocks, as an aid in mutation breeding. Several mutants were produced in all the material studied, but none of them have yet reached a sufficient developmental stage to enable their complete assessment. On the basis of the results obtained so far the following conclusions can be drawn: higher doses of irradiation resulted in higher frequency of mutants in most apple cultivars and apple rootstocks; in sour cherries the effect of dose depended on the cultivars. Among V 1 shoots developed from sleeping buds on irradiated scion wood, compact mutants were found; their frequency, however, was about 60% lower than among V 1 shoots developed directly from irradiated dormant buds. In apple rootstocks A 2 and M 26 several dwarfed mutants were found; some of these produced thorny plants and some had lower rooting ability; both these characteristics are inferior from the practical point of view. Multiplication and rooting media for in vitro propagation of apple rootstocks, worked out for M 26, were found unsuitable for the rootstocks P 2 and P 22; modifications made in the growth substance composition of the above media enabled satisfactory propagation to be obtained. (author)

Porta-enxertos para o cultivar Máximo IAC 138-22 de uvas de vinho em Monte Alegre do Sul, SP Rootstocks for wine grape cultivar IAC 138-22

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Maurilo Monteiro Terra

1990-01-01

Full Text Available Em Monte Alegre do Sul, SP, efetuou-se um experimento de longa duração para observar o comportamento do cultivar IAC 138-22 (Máximo de uvas para vinho, sobre cinco porta-enxertos: RR 101-14, 'Golia', "Ripária do Traviú', IAC 572 e IAC 313. Em oito colheitas sucessivas anuais, de 1974 a 1981, analisaram-se as produções médias de uvas por planta. Os resultados indicaram que o IAC 572' foi o melhor porta-enxerto para o IAC 138-22 'Máximo'. O IAC 313 superou o IAC 572 em um dos anos estudados. Todos os outros porta-enxertos apresentaram desempenho inferior.A long term experiment was conducted at Monte Alegre do Sul, State of São Paulo, Brazil, to study the behaviour of wine grape cultivar IAC 138-22 Máximo on five rootstocks: RR 101 14, 'Golia', "Ripária do Traviú', IAC 313 and IAC 572 The yields of eight consecutive annual harvests (from 1974 to 1981 were analysed. The results indicated that IAC 572 was the best rootstock. IAC 313 can also be used but with fair results. "Ripária do Traviú', RR 101-14 and 'Golia' are not recommended as rootstocks for IAC 138-22. Considering the row spacing (2 x 1m which allows 5,000 plants/ha, the difference between average yields of the best and the worst rootstock was 8,475kg/ha of grapes, a considerable figure for the grape grower.

Multiplexing clonality: combining RGB marking and genetic barcoding

Science.gov (United States)

Cornils, Kerstin; Thielecke, Lars; Hüser, Svenja; Forgber, Michael; Thomaschewski, Michael; Kleist, Nadja; Hussein, Kais; Riecken, Kristoffer; Volz, Tassilo; Gerdes, Sebastian; Glauche, Ingmar; Dahl, Andreas; Dandri, Maura; Roeder, Ingo; Fehse, Boris

2014-01-01

RGB marking and DNA barcoding are two cutting-edge technologies in the field of clonal cell marking. To combine the virtues of both approaches, we equipped LeGO vectors encoding red, green or blue fluorescent proteins with complex DNA barcodes carrying color-specific signatures. For these vectors, we generated highly complex plasmid libraries that were used for the production of barcoded lentiviral vector particles. In proof-of-principle experiments, we used barcoded vectors for RGB marking of cell lines and primary murine hepatocytes. We applied single-cell polymerase chain reaction to decipher barcode signatures of individual RGB-marked cells expressing defined color hues. This enabled us to prove clonal identity of cells with one and the same RGB color. Also, we made use of barcoded vectors to investigate clonal development of leukemia induced by ectopic oncogene expression in murine hematopoietic cells. In conclusion, by combining RGB marking and DNA barcoding, we have established a novel technique for the unambiguous genetic marking of individual cells in the context of normal regeneration as well as malignant outgrowth. Moreover, the introduction of color-specific signatures in barcodes will facilitate studies on the impact of different variables (e.g. vector type, transgenes, culture conditions) in the context of competitive repopulation studies. PMID:24476916

Maximum gravitational redshift of white dwarfs

International Nuclear Information System (INIS)

Shapiro, S.L.; Teukolsky, S.A.

1976-01-01

The stability of uniformly rotating, cold white dwarfs is examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordtvedt. The maximum central density and gravitational redshift of a white dwarf are determined as functions of five of the nine PPN parameters (γ, β, zeta 2 , zeta 3 , and zeta 4 ), the total angular momentum J, and the composition of the star. General relativity predicts that the maximum redshifts is 571 km s -1 for nonrotating carbon and helium dwarfs, but is lower for stars composed of heavier nuclei. Uniform rotation can increase the maximum redshift to 647 km s -1 for carbon stars (the neutronization limit) and to 893 km s -1 for helium stars (the uniform rotation limit). The redshift distribution of a larger sample of white dwarfs may help determine the composition of their cores

Axion cooling of white dwarfs

OpenAIRE

Isern, J.; Catalan, S.; Garcia--Berro, E.; Salaris, M.; Torres, S.

2013-01-01

The evolution of white dwarfs is a simple gravothermal process. This process can be tested in two ways, through the luminosity function of these stars and through the secular variation of the period of pulsation of those stars that are variable. Here we show how the mass of the axion can be constrained using the white dwarf luminosity function.

THE NIRSPEC ULTRACOOL DWARF RADIAL VELOCITY SURVEY

International Nuclear Information System (INIS)

Blake, Cullen H.; Charbonneau, David; White, Russel J.

2010-01-01

We report the results of an infrared Doppler survey designed to detect brown dwarf and giant planetary companions to a magnitude-limited sample of ultracool dwarfs. Using the NIRSPEC spectrograph on the Keck II telescope, we obtained approximately 600 radial velocity (RV) measurements over a period of six years of a sample of 59 late-M and L dwarfs spanning spectral types M8/L0 to L6. A subsample of 46 of our targets has been observed on three or more epochs. We rely on telluric CH 4 absorption features in Earth's atmosphere as a simultaneous wavelength reference and exploit the rich set of CO absorption features found in the K-band spectra of cool stars and brown dwarfs to measure RVs and projected rotational velocities. For a bright, slowly rotating M dwarf standard we demonstrate an RV precision of 50 m s -1 and for slowly rotating L dwarfs we achieve a typical RV precision of approximately 200 m s -1 . This precision is sufficient for the detection of close-in giant planetary companions to mid-L dwarfs as well as more equal mass spectroscopic binary systems with small separations (a +0.7 -0.6 Gyr, similar to that of nearby sun-like stars. We simulate the efficiency with which we detect spectroscopic binaries and find that the rate of tight (a +8.6 -1.6 %, consistent with recent estimates in the literature of a tight binary fraction of 3%-4%.

Nucleosynthesis in cold white dwarf explosions

International Nuclear Information System (INIS)

Canal, R.; Hernanz, M.

1986-01-01

Type I supernovae (SNI) are generally thought to be the main contributors to the galactic nucleosynthesis of iron-peak elements and their yields of intermediate-mass elements may also be important. We concentrate here upon a different class of models, based on the explosion of cold, massive, partially solid white dwarfs. We show that such white dwarfs must be relatively frequent among SNI progenitors and how their hydrodynamics upon ignition is very different from that of hotter, fluid white dwarfs. The implications for nucleosynthesis are briefly discussed and some preliminary results are presented

Comportamento da laranjera 'Folha Murcha' em sete porta-enxertos no noroeste do Paraná Performance of 'Folha Murcha' orange on seven rootstocks in northwest of Parana

Directory of Open Access Journals (Sweden)

Neusa Maria Colauto Stenzel

2005-12-01

Full Text Available Este trabalho avaliou por um período de 14 anos, em Paranavaí-PR, o comportamento de plantas de laranjeira 'Folha Murcha' enxertadas nos porta-enxertos: limoeiros 'Cravo' (Citrus limonia, 'Rugoso da África' (Citrus jambhiri e 'Volkameriano' (Citrus volkameriana, citrangeiro 'C-13' (Citrus sinensis x Poncirus trifoliata, trifoliata (Poncirus trifoliata, tangerineiras 'Sunki' (Citrus sunki e 'Cleópatra' (Citrus reshni. O delineamento experimental utilizado foi o de blocos ao acaso, com sete tratamentos (porta-enxertos e quatro repetições, com três plantas por parcela. Os volumes das copas de plantas em tangerineira 'Cleópatra' e limoeiro 'Rugoso da África' foram significativamente maiores. Plantas em limoeiro 'Cravo' apresentaram a menor diferença entre os diâmetros dos troncos do porta-enxerto e da copa. A produção acumulada foi superior nas plantas em limoeiro 'Rugoso da África' e tangerineira 'Cleópatra' e menor em plantas sobre o trifoliata. A alternância da produção não foi acentuada nas plantas sobre os porta-enxertos avaliados. O teor de sólidos solúveis totais foi significativamente superior nos frutos obtidos de plantas enxertadas em trifoliata e menor em limoeiro 'Rugoso da África'. A qualidade do suco apresentou-se dentro dos padrões aceitáveis para variedades-copa de laranjeiras. A tangerineira 'Cleópatra' e o limoeiro 'Rugoso da África' são porta-enxertos promissores para a laranjeira 'Folha Murcha' nas condições avaliadas.This work evaluated for 14 years, in Paranavaí, PR, Brazil, the performance of 'Folha Murcha' orange trees budded on the following rootstocks: 'Rangpur' lime (Citrus limonia, 'African' rough lemon (Citrus jambhiri, 'Volkamer' lemon (Citrus volkameriana, 'C-13' citrange (Citrus sinensis × Poncirus trifoliata, trifoliate orange (Poncirus trifoliata, 'Sunki' mandarin (Citrus sunki and 'Cleopatra' mandarin (Citrus reshni. The experimental design was in blocks, with seven treatments

White dwarf models of supernovae and cataclysmic variables

International Nuclear Information System (INIS)

Nomoto, K.; Hashimoto, M.

1986-01-01

If the accreting white dwarf increases its mass to the Chandrasekhar mass, it will either explode as a Type I supernova or collapse to form a neutron star. In fact, there is a good agreement between the exploding white dwarf model for Type I supernovae and observations. We describe various types of evolution of accreting white dwarfs as a function of binary parameters (i.e,. composition, mass, and age of the white dwarf, its companion star, and mass accretion rate), and discuss the conditions for the precursors of exploding or collapsing white dwarfs, and their relevance to cataclysmic variables. Particular attention is given to helium star cataclysmics which might be the precursors of some Type I supernovae or ultrashort period x-ray binaries. Finally we present new evolutionary calculations using the updated nuclear reaction rates for the formation of O+Ne+Mg white dwarfs, and discuss the composition structure and their relevance to the model for neon novae. 61 refs., 14 figs

Is EG 50 a White or Strange Dwarf?

Science.gov (United States)

Hajyan, G. S.; Vartanyan, Yu. L.

2017-12-01

The time dependences of the luminosity of a white dwarf and four strange dwarfs with masses of 0.5 M (the mass of the white dwarf EG 50 with a surface temperature of 2.1·104 K) are determined taking neutrino energy losses into account. It was assumed that these configurations radiate only at the expense of thermal energy reserves. It is shown that the sources of thermal energy owing to nonequilibrium b-processes and the phenomenon of crystallization of electron-nuclear matter are insignificant in determining the cooling time of white and strange dwarfs with masses of 0.5 M⨀. It is shown that in this approximation the time dependences of the luminosity of white and strange dwarfs with masses of 0.5 M⨀ differ significantly only for surface temperatures TR≥7·104 K, so it is impossible to determine whether EG 50 is a white or strange dwarf based on the cooling time.

White dwarf evolution - Cradle-to-grave constraints via pulsation

Science.gov (United States)

Kawaler, Steven D.

1990-01-01

White dwarf evolution, particularly in the early phases, is not very strongly constrained by observation. Fortunately, white dwarfs undergo nonradial pulsation in three distinct regions of the H-R diagram. These pulsations provide accurate masses, surface compositional structure and rotation velocities, and help constrain other important physical properties. We demonstrate the application of the tools of stellar seismology to white dwarf evolution using the hot white dwarf star PG 1159-035 and the cool DAV (or ZZ Ceti) stars as examples. From pulsation studies, significant challenges to the theory of white dwarf evolution emerge.

Clonal forestry, heterosis and advanced-generation breeding

Energy Technology Data Exchange (ETDEWEB)

Tuskan, G.A.

1997-08-01

This report discusses the clonal planting stock offers many advantages to the forest products industry. Advanced-generation breeding strategies should be designed to maximize within-family variance and at the same time allow the capture of heterosis. Certainly there may be a conflict in the choice of breeding strategy based on the trait of interest. It may be that the majority of the traits express heterosis due to overdominance. Alternatively, disease resistance is expressed as the lack of a specific metabolite or infection court then the homozygous recessive genotype may be the most desirable. Nonetheless, as the forest products industry begins to utilize the economic advantages of clonal forestry, breeding strategies will have to be optimized for these commercial plant materials. Here, molecular markers can be used to characterize the nature of heterosis and therefore define the appropriate breeding strategy.

Big Bang Tumor Growth and Clonal Evolution.

Science.gov (United States)

Sun, Ruping; Hu, Zheng; Curtis, Christina

2018-05-01

The advent and application of next-generation sequencing (NGS) technologies to tumor genomes has reinvigorated efforts to understand clonal evolution. Although tumor progression has traditionally been viewed as a gradual stepwise process, recent studies suggest that evolutionary rates in tumors can be variable with periods of punctuated mutational bursts and relative stasis. For example, Big Bang dynamics have been reported, wherein after transformation, growth occurs in the absence of stringent selection, consistent with effectively neutral evolution. Although first noted in colorectal tumors, effective neutrality may be relatively common. Additionally, punctuated evolution resulting from mutational bursts and cataclysmic genomic alterations have been described. In this review, we contrast these findings with the conventional gradualist view of clonal evolution and describe potential clinical and therapeutic implications of different evolutionary modes and tempos. Copyright © 2018 Cold Spring Harbor Laboratory Press; all rights reserved.

Searching for chemical signatures of brown dwarf formation

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Maldonado, J.; Villaver, E.

2017-06-01

Context. Recent studies have shown that close-in brown dwarfs in the mass range 35-55 MJup are almost depleted as companions to stars, suggesting that objects with masses above and below this gap might have different formation mechanisms. Aims: We aim to test whether stars harbouring massive brown dwarfs and stars with low-mass brown dwarfs show any chemical peculiarity that could be related to different formation processes. Methods: Our methodology is based on the analysis of high-resolution échelle spectra (R 57 000) from 2-3 m class telescopes. We determine the fundamental stellar parameters, as well as individual abundances of C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, and Zn for a large sample of stars known to have a substellar companion in the brown dwarf regime. The sample is divided into stars hosting massive and low-mass brown dwarfs. Following previous works, a threshold of 42.5 MJup was considered. The metallicity and abundance trends of the two subsamples are compared and set in the context of current models of planetary and brown dwarf formation. Results: Our results confirm that stars with brown dwarf companions do not follow the well-established gas-giant planet metallicity correlation seen in main-sequence planet hosts. Stars harbouring massive brown dwarfs show similar metallicity and abundance distribution as stars without known planets or with low-mass planets. We find a tendency of stars harbouring less-massive brown dwarfs of having slightly higher metallicity, [XFe/Fe] values, and abundances of Sc II, Mn I, and Ni I than the stars having the massive brown dwarfs. The data suggest, as previously reported, that massive and low-mass brown dwarfs might present differences in period and eccentricity. Conclusions: We find evidence of a non-metallicity dependent mechanism for the formation of massive brown dwarfs. Our results agree with a scenario in which massive brown dwarfs are formed as stars. At high metallicities, the core

A low-temperature companion to a white dwarf star

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Becklin, E. E.; Zuckerman, B.

1988-01-01

An infrared object located about 120 AU from the white dwarf GD165 has been discovered. With the exception of the possible brown dwarf companion to Giclas 29-38 reported last year, the companion to GD165 is the coolest (2100 K) dwarf star ever reported and, according to some theoretical models, it should be a substellar brown dwarf with a mass between 0.06 and 0.08 solar mass. These results, together with newly discovered low-mass stellar companions to white dwarfs, change the investigation of very low-mass stars from the study of a few chance objects to that of a statistical distribution. In particular, it appears that very low-mass stars and perhaps even brown dwarfs could be quite common in the Galaxy.

High-throughput monitoring of integration site clonality in preclinical and clinical gene therapy studies

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Frank A Giordano

Full Text Available Gene transfer to hematopoietic stem cells with integrating vectors not only allows sustained correction of monogenic diseases but also tracking of individual clones in vivo. Quantitative real-time PCR (qPCR has been shown to be an accurate method to quantify individual stem cell clones, yet due to frequently limited amounts of target material (especially in clinical studies, it is not useful for large-scale analyses. To explore whether vector integration site (IS recovery techniques may be suitable to describe clonal contributions if combined with next-generation sequencing techniques, we designed artificial ISs of different sizes which were mixed to simulate defined clonal situations in clinical settings. We subjected all mixes to either linear amplification–mediated PCR (LAM-PCR or nonrestrictive LAM-PCR (nrLAM-PCR, both combined with 454 sequencing. We showed that nrLAM-PCR/454-detected clonality allows estimating qPCR-detected clonality in vitro. We then followed the kinetics of two clones detected in a patient enrolled in a clinical gene therapy trial using both, nrLAM-PCR/454 and qPCR and also saw nrLAM-PCR/454 to correlate to qPCR-measured clonal contributions. The method presented here displays a feasible high-throughput strategy to monitor clonality in clinical gene therapy trials is at hand.

Effects of transient soil waterlogging and its importance for rootstock selection

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Michelle Morales-Olmedo

2015-08-01

Full Text Available Under transient waterlogging, a number of transformations in the soil are generated associated with lack of aeration, seriously affecting the root system. Significant progress has been reported on understanding the effects of lack of oxygen on the metabolism of the roots, although few studies have examined changes in the soil. Diverging conclusions about the degree of tolerance exhibited by plants exclude the effects of hypoxia and anoxia on physical-chemical soil properties under plant experiments. This review examines the main changes occurring in soil and roots due to transient soil waterlogging conditions. Parameters such as antioxidant capacity, nutrient uptake dynamics and regeneration and distribution of the root system are relevant for selecting rootstocks tolerant to soil waterlogging.

The Living with a Red Dwarf / Goldiloks Program: The Activity-Rotation-Age Relationships of M and K Dwarfs

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Engle, Scott; Guinan, Edward Francis

2018-01-01

Over the past several years, the database of M dwarfs with determined ages has continually expanded, allowing us to furnish Activity-Rotation-Age Relationships as part of the Living with a Red Dwarf program. We have now begun to expand this successful program to also cover K dwarfs - the Goldiloks program. Both M and K dwarfs suffer from the same limitation - due to their long lifetimes and very slow nuclear evolution, the best method for determining ages for a large number of M and K dwarf targets is through “magnetic tracers” such as X-UV activity levels and stellar rotation rates. We report on the current results of our relationships: deriving photometric rotation rates; gathering X-UV measures with HST, IUE Chandra and XMM (both proposed by us, and archival); and assessing their impacts on our understanding of the evolutions and habitability of these stellar types.We gratefully acknowledge the support from NSF/RUI Grant AST 1009903, Chandra Grant GO-13200633, HST Grants GO-12124X and GO-13020X.

Space distribution and physical properties of cool dwarf stars

International Nuclear Information System (INIS)

Staller, R.F.A.

1979-01-01

A new study of the space density of red dwarfs based on a sample of red dwarfs in a field of 238 square degrees towards the South Galactic Pole is presented. A blink survey using red and blue copies of Mount Palomar Sky Survey plates of a six square degrees field centered on the South Galactic Pole was performed and the results (approximately 2500 red objects) and the discussion of these results are presented. The time that elapsed before a black dwarf becomes invisible is estimated and is suggested that low-velocity red dwarfs could be explained by contracting black dwarfs. Based on theoretical considerations it can be shown that the existence of a large number of low-velocity stars is in serious conflict with criteria for the stability of the galactic disk. It is shown that if one also takes into account all generations of black dwarfs that are already invisible and therfore old, the mean velocity of all black dwarfs is much higher so that there is no conflict with theory. Luminosity functions of red and black dwarfs in several photometric passbands are calculated. (Auth.)

A possible magnetic DA white dwarf

International Nuclear Information System (INIS)

Wickramasinghe, D.T.; Bessell, M.S.

1976-01-01

The spectrum of a peculiar southern white dwarf suspect BPM 25114 is described. A possible magnetic interpretation suggests a DA white dwarf with a field of about 10 7 gauss. The star appears to be both a spectrum variable and perhaps light variable

Long-lived ames dwarf mice are resistant to chemical stressors.

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Bokov, Alex F; Lindsey, Merry L; Khodr, Christina; Sabia, Marian R; Richardson, Arlan

2009-08-01

To probe the connection between longevity and stress resistance, we compared the sensitivity of Ames long-lived dwarf mice and control littermates with paraquat, diquat, and dobutamine. In young adult animals, 95% of male and 39% of female controls died after paraquat administration, but no dwarf animals died. When the experiment was repeated at an older age or a higher dosage of paraquat, dwarf mice still showed greater resistance. Dwarf mice also were more resistant to diquat; 80% of male and 60% of female controls died compared with 40% and 20% of dwarf mice, despite greater sensitivity of dwarf liver to diquat. Dwarf mice were also less sensitive to dobutamine-induced cardiac stress and had lower levels of liver and lung F(2)-isoprostanes. This is the first direct in vivo evidence that long-lived Ames dwarf mice have enhanced resistance to chemical insult, particularly oxidative stressors.

Clonal growth strategy, diversity and structure: A spatiotemporal response to sedimentation in tropical Cyperus papyrus swamps.

Science.gov (United States)

Geremew, Addisie; Stiers, Iris; Sierens, Tim; Kefalew, Alemayehu; Triest, Ludwig

2018-01-01

Land degradation and soil erosion in the upper catchments of tropical lakes fringed by papyrus vegetation can result in a sediment load gradient from land to lakeward. Understanding the dynamics of clonal modules (ramets and genets) and growth strategies of plants on such a gradient in both space and time is critical for exploring a species adaptation and processes regulating population structure and differentiation. We assessed the spatial and temporal dynamics in clonal growth, diversity, and structure of an emergent macrophyte, Cyperus papyrus (papyrus), in response to two contrasting sedimentation regimes by combining morphological traits and genotype data using 20 microsatellite markers. A total of 636 ramets from six permanent plots (18 x 30 m) in three Ethiopian papyrus swamps, each with discrete sedimentation regimes (high vs. low) were sampled for two years. We found that ramets under the high sedimentation regime (HSR) were significantly clumped and denser than the sparse and spreading ramets under the low sedimentation regime (LSR). The HSR resulted in significantly different ramets with short culm height and girth diameter as compared to the LSR. These results indicated that C. papyrus ameliorates the effect of sedimentation by shifting clonal growth strategy from guerrilla (in LSR) to phalanx (in HSR). Clonal richness, size, dominance, and clonal subrange differed significantly between sediment regimes and studied time periods. Each swamp under HSR revealed a significantly high clonal richness (R = 0.80) as compared to the LSR (R = 0.48). Such discrepancy in clonal richness reflected the occurrence of initial and repeated seedling recruitment strategies as a response to different sedimentation regimes. Overall, our spatial and short-term temporal observations highlighted that HSR enhances clonal richness and decreases clonal subrange owing to repeated seedling recruitment and genets turnover.

Sweating the small stuff: simulating dwarf galaxies, ultra-faint dwarf galaxies, and their own tiny satellites

Science.gov (United States)

Wheeler, Coral; Oñorbe, Jose; Bullock, James S.; Boylan-Kolchin, Michael; Elbert, Oliver D.; Garrison-Kimmel, Shea; Hopkins, Philip F.; Kereš, Dušan

2015-10-01

We present Feedback in Realistic Environment (FIRE)/GIZMO hydrodynamic zoom-in simulations of isolated dark matter haloes, two each at the mass of classical dwarf galaxies (Mvir ≃ 1010 M⊙) and ultra-faint galaxies (Mvir ≃ 109 M⊙), and with two feedback implementations. The resulting central galaxies lie on an extrapolated abundance matching relation from M⋆ ≃ 106 to 104 M⊙ without a break. Every host is filled with subhaloes, many of which form stars. Each of our dwarfs with M⋆ ≃ 106 M⊙ has 1-2 well-resolved satellites with M⋆ = 3-200 × 103 M⊙. Even our isolated ultra-faint galaxies have star-forming subhaloes. If this is representative, dwarf galaxies throughout the Universe should commonly host tiny satellite galaxies of their own. We combine our results with the Exploring the Local Volume in Simulations (ELVIS) simulations to show that targeting ˜ 50 kpc regions around nearby isolated dwarfs could increase the chances of discovering ultra-faint galaxies by ˜35 per cent compared to random pointings, and specifically identify the region around the Phoenix dwarf galaxy as a good potential target. The well-resolved ultra-faint galaxies in our simulations (M⋆ ≃ 3-30 × 103 M⊙) form within Mpeak ≃ 0.5-3 × 109 M⊙ haloes. Each has a uniformly ancient stellar population ( > 10 Gyr) owing to reionization-related quenching. More massive systems, in contrast, all have late-time star formation. Our results suggest that Mhalo ≃ 5 × 109 M⊙ is a probable dividing line between haloes hosting reionization `fossils' and those hosting dwarfs that can continue to form stars in isolation after reionization.

THE BROWN DWARF KINEMATICS PROJECT (BDKP). IV. RADIAL VELOCITIES OF 85 LATE-M AND L DWARFS WITH MagE

Energy Technology Data Exchange (ETDEWEB)

Burgasser, Adam J. [Center for Astrophysics and Space Science, University of California San Diego, La Jolla, CA 92093 (United States); Logsdon, Sarah E. [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); Gagné, Jonathan [Institute for Research on Exoplanets (iREx), Université de Montréal, Département de Physique, C.P. 6128 Succ. Centre-ville, Montréal, QC H3C 3J7 (Canada); Bochanski, John J. [Rider University, 2083 Lawrenceville Road, Lawrenceville, NJ 08648 (United States); Faherty, Jaqueline K. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, Washington, DC 20015 (United States); West, Andrew A. [Department of Astronomy, Boston University, 725 Commonwealth Avenue Boston, MA 02215 (United States); Mamajek, Eric E. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Schmidt, Sarah J. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Cruz, Kelle L., E-mail: aburgasser@ucsd.edu [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10034 (United States)

2015-09-15

Radial velocity measurements are presented for 85 late M- and L-type very low-mass stars and brown dwarfs obtained with the Magellan Echellette spectrograph. Targets primarily have distances within 20 pc of the Sun, with more distant sources selected for their unusual spectral energy distributions. We achieved precisions of 2–3 km s{sup −1}, and combined these with astrometric and spectrophotometric data to calculate UVW velocities. Most are members of the thin disk of the Galaxy, and velocity dispersions indicate a mean age of 5.2 ± 0.2 Gyr for sources within 20 pc. We find signficantly different kinematic ages between late-M dwarfs (4.0 ± 0.2 Gyr) and L dwarfs (6.5 ± 0.4 Gyr) in our sample that are contrary to predictions from prior simulations. This difference appears to be driven by a dispersed population of unusually blue L dwarfs which may be more prevalent in our local volume-limited sample than in deeper magnitude-limited surveys. The L dwarfs exhibit an asymmetric U velocity distribution with a net inward flow, similar to gradients recently detected in local stellar samples. Simulations incorporating brown dwarf evolution and Galactic orbital dynamics are unable to reproduce the velocity asymmetry, suggesting non-axisymmetric perturbations or two distinct L dwarf populations. We also find the L dwarfs to have a kinematic age-activity correlation similar to more massive stars. We identify several sources with low surface gravities, and two new substellar candidate members of nearby young moving groups: the astrometric binary DENIS J08230313–4912012AB, a low-probability member of the β Pictoris Moving Group; and 2MASS J15104786–2818174, a moderate-probability member of the 30–50 Myr Argus Association.

The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals

Science.gov (United States)

Kazantzidis, Stelios; Mayer, Lucio; Callegari, Simone; Dotti, Massimo; Moustakas, Leonidas A.

2017-02-01

A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their origin. In this context, the tidal stirring model postulates that interactions with MW-sized hosts can transform rotationally supported dwarfs, resembling present-day dwarf irregular (dIrr) galaxies, into systems with the kinematic and structural properties of dSphs. Using N-body+SPH simulations, we investigate the dependence of this transformation mechanism on the gas fraction, f gas, in the disk of the progenitor dwarf. Our numerical experiments incorporate for the first time the combined effects of radiative cooling, ram-pressure stripping, star formation, supernova (SN) winds, and a cosmic UV background. For a given orbit inside the primary galaxy, rotationally supported dwarfs with gas fractions akin to those of observed dIrrs (f gas ≳ 0.5), demonstrate a substantially enhanced likelihood and efficiency of transformation into dSphs relative to their collisionless (f gas = 0) counterparts. We argue that the combination of ram-pressure stripping and SN winds causes the gas-rich dwarfs to respond more impulsively to tides, augmenting their transformation. When f gas ≳ 0.5, disky dwarfs on previously unfavorable low-eccentricity or large-pericenter orbits are still able to transform. On the widest orbits, the transformation is incomplete; the dwarfs retain significant rotational support, a relatively flat shape, and some gas, naturally resembling transition-type systems. We conclude that tidal stirring constitutes a prevalent evolutionary mechanism for shaping the structure of dwarf galaxies within the currently favored CDM cosmological paradigm.

The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals

Energy Technology Data Exchange (ETDEWEB)

Kazantzidis, Stelios [Section of Astrophysics, Astronomy and Mechanics, Department of Physics, National and Kapodistrian University of Athens, 15784 Zografos, Athens (Greece); Mayer, Lucio [Center for Theoretical Astrophysics and Cosmology, Institute for Computational Science, University of Zürich, CH-8057 Zürich (Switzerland); Callegari, Simone [Anthropology Institute and Museum, University of Zürich, CH-8057 Zürich (Switzerland); Dotti, Massimo [Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano (Italy); Moustakas, Leonidas A., E-mail: skazantzidis@phys.uoa.gr [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States)

2017-02-10

A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their origin. In this context, the tidal stirring model postulates that interactions with MW-sized hosts can transform rotationally supported dwarfs, resembling present-day dwarf irregular (dIrr) galaxies, into systems with the kinematic and structural properties of dSphs. Using N -body+SPH simulations, we investigate the dependence of this transformation mechanism on the gas fraction, f {sub gas}, in the disk of the progenitor dwarf. Our numerical experiments incorporate for the first time the combined effects of radiative cooling, ram-pressure stripping, star formation, supernova (SN) winds, and a cosmic UV background. For a given orbit inside the primary galaxy, rotationally supported dwarfs with gas fractions akin to those of observed dIrrs ( f {sub gas} ≳ 0.5), demonstrate a substantially enhanced likelihood and efficiency of transformation into dSphs relative to their collisionless ( f {sub gas} = 0) counterparts. We argue that the combination of ram-pressure stripping and SN winds causes the gas-rich dwarfs to respond more impulsively to tides, augmenting their transformation. When f {sub gas} ≳ 0.5, disky dwarfs on previously unfavorable low-eccentricity or large-pericenter orbits are still able to transform. On the widest orbits, the transformation is incomplete; the dwarfs retain significant rotational support, a relatively flat shape, and some gas, naturally resembling transition-type systems. We conclude that tidal stirring constitutes a prevalent evolutionary mechanism for shaping the structure of dwarf galaxies within the currently favored CDM cosmological paradigm.

Enraizamento in vitro de porta-enxertos de Prunus In vitro rooting of Prunus rootstocks

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Marcelo Rogalski

2003-08-01

Full Text Available Na micropropagação de Prunus sp., o enraizamento tem sido considerado uma fase crítica, pois determina a sobrevivência das plantas durante a aclimatização. Dentre os fatores importantes ao enraizamento in vitro, destacam-se o genótipo e as auxinas por serem determinantes na indução e na formação de raízes. O objetivo deste trabalho foi avaliar o efeito de diferentes concentrações de IBA no enraizamento in vitro dos porta-enxertos de espécies do gênero Prunus: cultivares Capdeboscq e GF677, e seleções VP411 e VP417. Para o enraizamento in vitro, brotos com 2-3cm de comprimento foram introduzidos em meio de Lepoivre suplementado com 0,1; 0,5; 1,0 e 2,0 mg.L-1 IBA. Observou-se que o porta-enxerto 'Capdeboscq' apresentou maior taxa de enraizamento e maior número de raízes in vitro, sendo superior aos demais genótipos quanto a estas características. O nível de 1,0 mg.L-1 de IBA esteve associado à maior taxa média de enraizamento (100%, 64% e 64,0%, respectivamente para os porta-enxertos 'Capdeboscq', 'GF677' e VP411. O nível de 2,0 mg.L-1 de IBA foi superior para a seleção VP417 com taxa de 64% de enraizamento. Para os porta-enxertos 'Capdeboscq' e 'GF677', o número máximo de raízes foi de 9,6 e 5,2 raízes por broto, respectivamente, em resposta ao nível de 2,0 mg.L-1 de IBA, enquanto as seleções VP411 e VP417 apresentaram o maior número de raízes (3,6 e 3,9, respectivamente em resposta ao nível de 1,0 mg.L-1 de IBA.In Prunus sp. micropropagation of rooting is considered a critical stage, since it determines the plant survival during the acclimatization. Among important factors associated with rooting, the genotype and the auxins are considered important in the induction and formation of roots. The objective of the present work was to evaluate the effect of different IBA on the in vitro rooting of Prunus rootstocks Capdeboscq and GF677, and the selections VP411 and VP417. For the in vitro rooting stage, shoots of

A multiwavelength study of superoutbursts in dwarf novae

International Nuclear Information System (INIS)

Woerd, H.J. van der.

1987-01-01

Dwarf novae are stellar systems consisting of two stars which orbit around each other within a few hours. In dwarf novae one of the stars, which is a bit smaller and less massive than our sun, loses matter to a very compact and degenerated star: a white dwarf. This white dwarf has nearly the same mass as our sun but its radius is about a hundred times smaller. The process of mass transport was studied on the basis of observations with the Exosat-satelite (European X-ray Observatory satelite). 397 refs.; 50 figs.; 21 tabs

White dwarf evolution - Cradle-to-grave constraints via pulsation

International Nuclear Information System (INIS)

Kawaler, S.D.

1990-01-01

White dwarf evolution, particularly in the early phases, is not very strongly constrained by observation. Fortunately, white dwarfs undergo nonradial pulsation in three distinct regions of the H-R diagram. These pulsations provide accurate masses, surface compositional structure and rotation velocities, and help constrain other important physical properties. We demonstrate the application of the tools of stellar seismology to white dwarf evolution using the hot white dwarf star PG 1159-035 and the cool DAV (or ZZ Ceti) stars as examples. From pulsation studies, significant challenges to the theory of white dwarf evolution emerge. 44 refs

IUE spectrophotometry of the DA4 primary in the short-period white dwarf-red dwarf spectroscopic binary Case 1

Science.gov (United States)

Sion, E. M.; Guinan, E. F.; Wesemael, F.

1984-01-01

Low-resolution ultraviolet International Ultraviolet Explorer spectra of the DA white dwarf Case 1 are presented. The spectra show the presence of the 1400 A feature, already discovered in several other DA stars, and of a shallower trough in the 1550-1700 A range. A model atmosphere analysis of the ultraviolet energy distribution of the Ly-alpha red wing yields T(e) = 13,000 + or - 500 K. Possible interpretations of the 1400 A feature are reviewed. Case 1 is the coolest white dwarf found in a short-period, detached white dwarf-red dwarf binary, and its cooling time is consistent with estimates of the efficiency of angular momentum removal mechanisms in the phases subsequent to common envelope binary evolution.

Conditions for accretion-induced collapse of white dwarfs

International Nuclear Information System (INIS)

Nomoto, Kenichi; Kondo, Yoji

1991-01-01

Recent discovery of an unexpectedly large number of low-mass binary pulsars (LMBPs) in globular clusters has instigated active discussions on the evolutionary origin of binary pulsars. Prompted by the possibility that at least some of LMBPs originate from accretion-induced collapse (AIC) of white dwarfs, a reexamination is conducted as to whether or not AIC occurs for the new models of O + Ne + Mg white dwarfs and solid C + O white dwarfs that can ignite explosive nuclear burning at significantly lower central densities than in the previous models. Even with low critical densities, AIC is still much more likely than explosion for both types of white dwarfs. Possible regions for AIC are presented in a diagram of mass accretion rate vs initial mass of the white dwarfs. 42 refs

Tidal Dwarf Galaxies and Missing Baryons

Directory of Open Access Journals (Sweden)

Frederic Bournaud

2010-01-01

Full Text Available Tidal dwarf galaxies form during the interaction, collision, or merger of massive spiral galaxies. They can resemble “normal” dwarf galaxies in terms of mass, size, and become dwarf satellites orbiting around their massive progenitor. They nevertheless keep some signatures from their origin, making them interesting targets for cosmological studies. In particular, they should be free from dark matter from a spheroidal halo. Flat rotation curves and high dynamical masses may then indicate the presence of an unseen component, and constrain the properties of the “missing baryons,” known to exist but not directly observed. The number of dwarf galaxies in the Universe is another cosmological problem for which it is important to ascertain if tidal dwarf galaxies formed frequently at high redshift, when the merger rate was high, and many of them survived until today. In this paper, “dark matter” is used to refer to the nonbaryonic matter, mostly located in large dark halos, that is, CDM in the standard paradigm, and “missing baryons” or “dark baryons” is used to refer to the baryons known to exist but hardly observed at redshift zero, and are a baryonic dark component that is additional to “dark matter”.

White dwarf stars with carbon atmospheres.

Science.gov (United States)

Dufour, P; Liebert, J; Fontaine, G; Behara, N

2007-11-22

White dwarfs represent the endpoint of stellar evolution for stars with initial masses between approximately 0.07 and 8-10, where is the mass of the Sun (more massive stars end their life as either black holes or neutron stars). The theory of stellar evolution predicts that the majority of white dwarfs have a core made of carbon and oxygen, which itself is surrounded by a helium layer and, for approximately 80 per cent of known white dwarfs, by an additional hydrogen layer. All white dwarfs therefore have been traditionally found to belong to one of two categories: those with a hydrogen-rich atmosphere (the DA spectral type) and those with a helium-rich atmosphere (the non-DAs). Here we report the discovery of several white dwarfs with atmospheres primarily composed of carbon, with little or no trace of hydrogen or helium. Our analysis shows that the atmospheric parameters found for these stars do not fit satisfactorily in any of the currently known theories of post-asymptotic giant branch evolution, although these objects might be the cooler counterpart of the unique and extensively studied PG 1159 star H1504+65 (refs 4-7). These stars, together with H1504+65, might accordingly form a new evolutionary sequence that follows the asymptotic giant branch.

HUBBLE SPACE TELESCOPE IMAGING AND SPECTRAL ANALYSIS OF TWO BROWN DWARF BINARIES AT THE L DWARF/T DWARF TRANSITION

International Nuclear Information System (INIS)

Burgasser, Adam J.; Bardalez-Gagliuffi, Daniella C.; Gizis, John E.

2011-01-01

We present a detailed examination of the brown dwarf multiples 2MASS J08503593+1057156 and 2MASS J17281150+3948593, both suspected of harboring components that straddle the L dwarf/T dwarf transition. Resolved photometry from Hubble Space Telescope/NICMOS shows opposite trends in the relative colors of the components, with the secondary of 2MASS J0850+1057 being redder than its primary, while that of 2MASS J1728+3948 is bluer. We determine near-infrared component types by matching combined-light, near-infrared spectral data to binary templates, with component spectra scaled to resolved NICMOS and K p photometry. Combinations of L7 + L6 for 2MASS J0850+1057 and L5 + L6.5 for 2MASS J1728+3948 are inferred. Remarkably, the primary of 2MASS J0850+1057 appears to have a later-type classification compared to its secondary, despite being 0.8-1.2 mag brighter in the near-infrared, while the primary of 2MASS J1728+3948 is unusually early for its combined-light optical classification. Comparison to absolute magnitude/spectral type trends also distinguishes these components, with 2MASS J0850+1057A being ∼1 mag brighter and 2MASS J1728+3948A ∼ 0.5 mag fainter than equivalently classified field counterparts. We deduce that thick condensate clouds are likely responsible for the unusual properties of 2MASS J1728+3948A, while 2MASS J0850+1057A is either an inflated young brown dwarf or a tight unresolved binary, making it potentially part of a wide, low-mass, hierarchical quintuple system.

Desenvolvimento vegetativo inicial de porta-enxertos cítricos cultivados em diferentes substratos Vegetative development of citrus rootstocks seedlings cultivated in different growing media

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Gilmar Schäfer

2006-12-01

Full Text Available Com o objetivo de avaliar o desenvolvimento vegetativo de porta-enxertos cítricos em diferentes substratos de cultivo, foi instalado um experimento, conduzido em casa de vegetação, com sistema de irrigação por microaspersão, na Estação Experimental Agronômica da UFRGS, a partir do dia 27 de setembro de 2001. O delineamento experimental adotado foi em blocos ao acaso, em esquema de parcela subdividida, com quatro repetições. Nas parcelas principais, foram testados substratos, sendo dois encontrados no comércio especializado em horticultura (Comercial 1 e 2 e uma mistura (turfa mais casca de arroz carbonizada - na proporção de 1:1 em v:v. Nas subparcelas, foram testados quatro porta-enxertos cítricos ("Trifoliata", Citrange "C13", Citrange "C37" e Limoeiro "Cravo". Os principais resultados demonstram que é possível produzir porta-enxertos, na fase de sementeira, com bom tamanho e desenvolvimento radicular, com 120 dias após a semeadura, e que as características químicas dos substratos são determinantes para o desenvolvimento adequado dos porta-enxertos, sendo prejudicial a salinidade elevada.The present study was aimed at evaluating the vegetative development of citrus seedlings rootstocks cultivated in different substrates. The experiment was installed at greenhouse conditions in the Estação Experimental Agronômica UFRGS, from September 27, 2001. The experimental design used was that of randomized blocks, in a split plot scheme, with four replications. In the main parcels were tested substrate, two commercial, found in the specialized trade in horticulture and a mixture. In the sub parcels were tested four citrus rootstock (Trifoliate orange, 'C13' Citrange, 'C37' Citrange and 'Rangpur' Lime. The main results showing that is possible to produce citrus rootstock seedlings with good size and root development, with 120 days after sowing. The chemistries characteristics of the substrate are decisive for the appropriate

Genetic Segregation Analysis of a Rapeseed Dwarf Mutant

International Nuclear Information System (INIS)

Xiang, G.; Yu, S.; Zhang, T.; Zhao, J.; Lei, S.; Du, C.

2016-01-01

Dwarf resources in Brassica napus are very important for developing high-yield cultivars through dwarf-type and lodging-resistant breeding. However, few dwarf varieties have been available for this species. Here, we reported a new rapeseed dwarf mutant GRC1157, which exhibits obvious phenotypic variations on dwarf. Six generations (P /sub 1/, P/sub 1/, F/sub 1/, F/sub 1/, B/sub 1/, and B/sub 1/) were produced from a cross between dwarf mutant GRC1157 and an elite tall-type line XR16 to analyze genetic inheritances of plant height (PH), numbers of the 1st valid branch (VBN), main inflorescence length (MIL), pod numbers per main inflorescence (MPN), pod length (PL) and seed numbers per pod (PSN) using the mixed major gene plus polygene inheritance model. The genetic analysis shows different traits were controlled by different inheritance models: PH and PL by two pairs of additive-dominant-epistatic major genes plus additive-dominant-epistatic polygenes, MPN and PSN by two-pair additive-dominant-epistatic major genes plus additive-dominant polygenes, MIL by two-pair additive-dominant-epistatic major genes and VBN by one-pair additive-dominant major genes plus additive-dominant-epistatic polygenes. Furthermore, positive correlations between PH and some other traits were observed, suggesting that some traits may be co-regulated by several linkage or same loci/genes. In addition, high heritability (40.35-93.7 percent) were found for five traits (except VBN) in different segregating generations, indicating these traits were mainly affected by hereditary factors and suitable for early artificial selection. In sum, the dwarf mutant GRC1157 can serve as a valuable resource for rapeseed dwarf breeding and the genetic analysis in this study provided a foundation for further mapping and cloning dwarf genes in mutant GRC1157. (author)

CCD photometry of apparent dwarf galaxies in Fornax

International Nuclear Information System (INIS)

Phillipps, S.; Grimley, P.L.; Disney, M.J.; Cawson, M.G.M.; Kibblewhite, E.J.

1986-01-01

Blue and red CCD surface photometry of two apparent dwarf galaxies in the Fornax cluster region is presented. Luminosity profiles are derived and their form discussed. The fainter galaxy resembles an archetypal diffuse dwarf elliptical but the brighter of the pair is either an unusual red dwarf or a background galaxy in chance juxtaposition. (author)

Comportamento da laranjeira Piralima sobre Poncirus trifoliata com variações na altura de enxertia Behaviour of Piralima orange on Poncirus trifoliata rootstock as a function of budding height

Directory of Open Access Journals (Sweden)

V.R. Sampaio

1994-04-01

Full Text Available Pesquisou-se a combinação de laranjeira Piralima, Citrus sinensis (L. Osb. sobre Poncirus trifoliata (L. Raf. fazendo-se variações nas alturas das enxertias, com operações efetuadas a zero, dez, vinte e quarenta centímetros de altura. Avaliações realizadas após seis anos e meio de implantação do experimento permitiram as seguintes conclusões: 1 as alturas das enxertias afetaram o desenvolvimento global das plantas, com as enxertias mais altas reforçando o efeito ananicante do Poncirus trifoliata; 2 as diferentes alturas de enxertia não afetaram as produções de frutos das três primeiras produções comerciais. Na quarta colheita surgiu diferença entre os tratamentos extremos, com maiores produções acontecendo para plantas enxertadas próximas ao solo; 3 o Poncirus trifoliata induziu características ananicantes às copas e as constantes boas produções de frutos de bom tamanho. Mostrou-se ser porta-enxerto interessante para o cultivar Piralima.The combination Poncirus trifoliata x Piralima acidless orange was studied as a function of the budding height, from zero to forty centimeters. After six and half years of evaluations the results led to the following conclusions: 1 variation in the budding height affected the plant global development: the higher was the budding height, the more intense was the Poncirus trifoliata dwarf effect. 2 variation in budding height did not affect orange yield during the first three commercial harvests. Difference occurred in the fourth harvest, between the extreme treatments, with larger yields for plants budded near to the soil. 3 Poncirus trifoliata induced dwarf characteristics to 'Piralima' stock as well as regular and good yield along the years, and the fruits were classified as high grade. Poncirus trifoliata showed to be an interesting rootstock for the cultivar Piralima.

A BROWN DWARF CENSUS FROM THE SIMP SURVEY

Energy Technology Data Exchange (ETDEWEB)

Robert, Jasmin; Gagné, Jonathan; Artigau, Étienne; Lafrenière, David; Nadeau, Daniel; Doyon, René; Malo, Lison; Albert, Loïc; Simard, Corinne [Département de physique and Observatoire du Mont-Mégantic, Université de Montréal, Montréal, QC H3C 3J7 (Canada); Gagliuffi, Daniella C. Bardalez; Burgasser, Adam J., E-mail: jasmin@astro.umontreal.ca [Center for Astrophysics and Space Sciences, University of California San Diego, 9500 Gilman Dr., Mail Code 0424, La Jolla, CA 92093 (United States)

2016-10-20

We have conducted a near-infrared (NIR) proper motion survey, the Sondage Infrarouge de Mouvement Propre, in order to discover field ultracool dwarfs (UCD) in the solar neighborhood. The survey was conducted by imaging ∼28% of the sky with the Caméra PAnoramique Proche-InfraRouge both in the southern hemisphere at the Cerro Tololo Inter-American Observatory 1.5 m telescope, and in the northern hemisphere at the Observatoire du Mont-Mégantic 1.6 m telescope and comparing the source positions from these observations with the Two Micron All-Sky Survey Point Source Catalog (2MASS PSC). Additional color criteria were used to further discriminate unwanted astrophysical sources. We present the results of an NIR spectroscopic follow-up of 169 M, L, and T dwarfs. Among the sources discovered are 2 young field brown dwarfs, 6 unusually red M and L dwarfs, 25 unusually blue M and L dwarfs, 2 candidate unresolved L+T binaries, and 24 peculiar UCDs. Additionally, we add 9 L/T transition dwarfs (L6–T4.5) to the already known objects.

A BROWN DWARF CENSUS FROM THE SIMP SURVEY

International Nuclear Information System (INIS)

Robert, Jasmin; Gagné, Jonathan; Artigau, Étienne; Lafrenière, David; Nadeau, Daniel; Doyon, René; Malo, Lison; Albert, Loïc; Simard, Corinne; Gagliuffi, Daniella C. Bardalez; Burgasser, Adam J.

2016-01-01

We have conducted a near-infrared (NIR) proper motion survey, the Sondage Infrarouge de Mouvement Propre, in order to discover field ultracool dwarfs (UCD) in the solar neighborhood. The survey was conducted by imaging ∼28% of the sky with the Caméra PAnoramique Proche-InfraRouge both in the southern hemisphere at the Cerro Tololo Inter-American Observatory 1.5 m telescope, and in the northern hemisphere at the Observatoire du Mont-Mégantic 1.6 m telescope and comparing the source positions from these observations with the Two Micron All-Sky Survey Point Source Catalog (2MASS PSC). Additional color criteria were used to further discriminate unwanted astrophysical sources. We present the results of an NIR spectroscopic follow-up of 169 M, L, and T dwarfs. Among the sources discovered are 2 young field brown dwarfs, 6 unusually red M and L dwarfs, 25 unusually blue M and L dwarfs, 2 candidate unresolved L+T binaries, and 24 peculiar UCDs. Additionally, we add 9 L/T transition dwarfs (L6–T4.5) to the already known objects.

Dwarf Galaxies in the Chandra COSMOS Legacy Survey

Science.gov (United States)

Civano, Francesca Maria; Mezcua, Mar; Fabbiano, Giuseppina; Marchesi, Stefano; Suh, Hyewon; Volonteri, Marta; cyrille

2018-01-01

The existence of intermediate mass black holes (100 7. While detecting these seed black holes in the young Universe is observationally challenging, the nuclei of local dwarf galaxies are among the best places where to look for them as these galaxies resemble in mass and metallicity the first galaxies and they have not significantly grown through merger and accretion processes. We present a sample of 40 AGN in dwarf galaxies (107 0.5, our sample constitutes the highest-redshift discovery of AGN in dwarf galaxies. One of the dwarf galaxies is the least massive galaxy (M* = 6.6x107 Msun) found so far to host an active BH. We also present for the first time the evolution of the AGN fraction with stellar mass, X-ray luminosity, and redshift in dwarf galaxies out to z = 0.7, finding that it decreases with X-ray luminosity and stellar mass. Unlike massive galaxies, the AGN fraction is found to decrease with redshift, suggesting that AGN in dwarf galaxies evolve differently than those in high-mass galaxies.

Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

International Nuclear Information System (INIS)

Memmi, H.; Couceiro, J.F.; Gijón, C.; Pérez-López, D.

2016-01-01

Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions. (Author)

Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.

Directory of Open Access Journals (Sweden)

Houssem Memmi

2016-06-01

Full Text Available Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx and leaf conductance (gl during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa. This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days. Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions.

Impacts of water stress, environment and rootstock on the diurnal behaviour of stem water potential and leaf conductance in pistachio (Pistacia vera L.)

Energy Technology Data Exchange (ETDEWEB)

Memmi, H.; Couceiro, J.F.; Gijón, C.; Pérez-López, D.

2016-11-01

Little information is available on the diurnal behaviour of water potential and leaf conductance on pistachio trees despite their relevance to fine tune irrigation strategies. Mature pistachio trees were subject to simultaneous measurements of stem water potential (Ψx) and leaf conductance (gl) during the day, at three important periods of the irrigation season. Trees were grown on three different rootstocks and water regimes. An initial baseline relating Ψx to air vapor pressure deficit (VPD) is presented for irrigation scheduling in pistachio. Ψx was closely correlated with VPD but with a different fit according to the degree of water stress. No evidence of the variation of Ψx in relation to the phenology of the tree was observed. Furthermore, midday Ψx showed more accuracy to indicate a situation of water stress than predawn water potential. Under well irrigated conditions, gl was positively correlated with VPD during stage II of growth reaching its peak when VPD reached its maximum value (around 4 kPa). This behaviour changed during stage III of fruit growth suggesting a reliance of stomatal behaviour to the phenological stage independently to the tree water status. The levels of water stress reached were translated in a slow recovery of tree water status and leaf conductance (more than 40 days). Regarding rootstocks, P. integerrima showed little adaptation to water shortage compared to the two other rootstocks under the studied conditions. (Author)

Possible new class of dense white dwarfs

International Nuclear Information System (INIS)

Glendenning, N.K.; Kettner, C.; Weber, F.

1995-01-01

If the strange quark matter hypothesis is true, then a new class of white dwarfs can exist whose nuclear material in their deep interiors can have a density as high as the neutron drip density, a few hundred times the density in maximum-mass white dwarfs and 4x10 4 the density in dwarfs of mass, M∼0.6 M circle-dot . Their masses fall in the approximate range 10 -4 to 1 M circle-dot . They are stable against acoustical modes of vibration. A strange quark core stabilizes these stars, which otherwise would have central densities that would place them in the unstable region of the sequence between white dwarfs and neutron stars. copyright 1995 American Institute of Physics

Citrus tristeza virus (CTV influence on the behavior of Tahiti lime (Citrus latifoliaTanaka grafted on six rootstocks in the plain piedmont of Colombia (1997-2008

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Hans Nicolás Chaparro Zambrano

2013-01-01

Full Text Available Tahiti lime, Citrus latifolia Tanaka (Rutaceae, is susceptible to Citrus Tristeza Virus (CTV, and if affected, decreases the profitability of the crop. In the well-drained high terrace of the Meta piedmont, the influence of the virus attack was evaluated on the performance of Tahiti lime grafted on six rootstocks (Carrizo; Sunki × English; Sunki × Jacobson; Pomeroy; Rubidoux, y Kryder 15-3 on a completely randomized experiment design taking each tree as an experimental unit. A comparison of means and inferential statistic were used for: plant height, height and canopy diameter; canopy volume, yield and severity of CTV. All rootstocks showed homogenous height. Carrizo was the exception with less size and canopy volume. The highest accumulated fruit yield (Kg/tree wasobtained by Sunki x English, followed by Rubidoux and the lowest yield was obtained by Carrizo. The highest yield efficiency of average canopy volume was obtained with Sunki x Jacobson. The Tahiti lime yield and morphological development fell in the seventh year (2007 in all rootstocks, due to an infection caused by a mix of isolates of CTV type Madeira and type B128, isolates which cause stem channeling : type B31 which causes moderate stem channeling and B7 and VT isolate,

Clonal analysis of stem cells in differentiation and disease.

Science.gov (United States)

Colom, Bartomeu; Jones, Philip H

2016-12-01

Tracking the fate of individual cells and their progeny by clonal analysis has redefined the concept of stem cells and their role in health and disease. The maintenance of cell turnover in adult tissues is achieved by the collective action of populations of stem cells with an equal likelihood of self-renewal or differentiation. Following injury stem cells exhibit striking plasticity, switching from homeostatic behavior in order to repair damaged tissues. The effects of disease states on stem cells are also being uncovered, with new insights into how somatic mutations trigger clonal expansion in early neoplasia. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Yield and fruit quality of peach scion by using rootstocks propagated by air layering and seed

OpenAIRE

Picolotto,Luciano; Fachinello,José Carlos; Bianchi,Valmor João; Manica-Berto,Roberta; Pasa,Mateus da Silveira; Schmitz,Juliano Dutra

2010-01-01

In rootstock propagation, several methods can be used; however few practices are adopted due to the lack of information about the behavior of stionic combinations at field. The work aimed to compare the propagation method by air layering with the traditional propagation system by seeds using the scion peach [Prunus persica (L.) Batsch] cultivar Granada. The following variables were measured: yield, fruit weight and size, skin color, flesh firmness, total soluble solids content (TSS) and titat...

POPULATION PROPERTIES OF BROWN DWARF ANALOGS TO EXOPLANETS

International Nuclear Information System (INIS)

Faherty, Jacqueline K.; Gagne, Jonathan; Weinberger, Alycia; Riedel, Adric R.; Cruz, Kelle L.; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Baldassare, Vivienne; Lemonier, Emily; Rice, Emily L.; Thorstensen, John R.; Tinney, C. G.

2016-01-01

We present a kinematic analysis of 152 low surface gravity M7-L8 dwarfs by adding 18 new parallaxes (including 10 for comparative field objects), 38 new radial velocities, and 19 new proper motions. We also add low- or moderate-resolution near-infrared spectra for 43 sources confirming their low surface gravity features. Among the full sample, we find 39 objects to be high-likelihood or new bona fide members of nearby moving groups, 92 objects to be ambiguous members and 21 objects that are non-members. Using this age-calibrated sample, we investigate trends in gravity classification, photometric color, absolute magnitude, color–magnitude, luminosity, and effective temperature. We find that gravity classification and photometric color clearly separate 5–130 Myr sources from >3 Gyr field objects, but they do not correlate one to one with the narrower 5–130 Myr age range. Sources with the same spectral subtype in the same group have systematically redder colors, but they are distributed between 1 and 4 σ from the field sequences and the most extreme outlier switches between intermediate- and low-gravity sources either confirmed in a group or not. The absolute magnitudes of low-gravity sources from the J band through W 3 show a flux redistribution when compared to equivalently typed field brown dwarfs that is correlated with spectral subtype. Low-gravity, late-type L dwarfs are fainter at J than the field sequence but brighter by W 3. Low-gravity M dwarfs are >1 mag brighter than field dwarfs in all bands from J through W 3. Clouds, which are a far more dominant opacity source for L dwarfs, are the likely cause. On color–magnitude diagrams, the latest-type, low-gravity L dwarfs drive the elbow of the L/T transition up to 1 mag redder and 1 mag fainter than field dwarfs at M J but are consistent with or brighter than the elbow at M W1 and M W2 . We conclude that low-gravity dwarfs carry an extreme version of the cloud conditions of field objects to lower

Infrared spectrum of an extremely cool white-dwarf star

Science.gov (United States)

Hodgkin; Oppenheimer; Hambly; Jameson; Smartt; Steele

2000-01-06

White dwarfs are the remnant cores of stars that initially had masses of less than 8 solar masses. They cool gradually over billions of years, and have been suggested to make up much of the 'dark matter' in the halo of the Milky Way. But extremely cool white dwarfs have proved difficult to detect, owing to both their faintness and their anticipated similarity in colour to other classes of dwarf stars. Recent improved models indicate that white dwarfs are much more blue than previously supposed, suggesting that the earlier searches may have been looking for the wrong kinds of objects. Here we report an infrared spectrum of an extremely cool white dwarf that is consistent with the new models. We determine the star's temperature to be 3,500 +/- 200 K, making it the coolest known white dwarf. The kinematics of this star indicate that it is in the halo of the Milky Way, and the density of such objects implied by the serendipitous discovery of this star is consistent with white dwarfs dominating the dark matter in the halo.

Identifying Likely Disk-hosting M dwarfs with Disk Detective

Science.gov (United States)

Silverberg, Steven; Wisniewski, John; Kuchner, Marc J.; Disk Detective Collaboration

2018-01-01

M dwarfs are critical targets for exoplanet searches. Debris disks often provide key information as to the formation and evolution of planetary systems around higher-mass stars, alongside the planet themselves. However, less than 300 M dwarf debris disks are known, despite M dwarfs making up 70% of the local neighborhood. The Disk Detective citizen science project has identified over 6000 new potential disk host stars from the AllWISE catalog over the past three years. Here, we present preliminary results of our search for new disk-hosting M dwarfs in the survey. Based on near-infrared color cuts and fitting stellar models to photometry, we have identified over 500 potential new M dwarf disk hosts, nearly doubling the known number of such systems. In this talk, we present our methodology, and outline our ongoing work to confirm systems as M dwarf disks.

The Effects of Ram-pressure Stripping and Supernova Winds on the Tidal Stirring of Disky Dwarfs: Enhanced Transformation into Dwarf Spheroidals

International Nuclear Information System (INIS)

Kazantzidis, Stelios; Mayer, Lucio; Callegari, Simone; Dotti, Massimo; Moustakas, Leonidas A.

2017-01-01

A conclusive model for the formation of dwarf spheroidal (dSph) galaxies still remains elusive. Owing to their proximity to the massive spirals Milky Way (MW) and M31, various environmental processes have been invoked to explain their origin. In this context, the tidal stirring model postulates that interactions with MW-sized hosts can transform rotationally supported dwarfs, resembling present-day dwarf irregular (dIrr) galaxies, into systems with the kinematic and structural properties of dSphs. Using N -body+SPH simulations, we investigate the dependence of this transformation mechanism on the gas fraction, f _g_a_s, in the disk of the progenitor dwarf. Our numerical experiments incorporate for the first time the combined effects of radiative cooling, ram-pressure stripping, star formation, supernova (SN) winds, and a cosmic UV background. For a given orbit inside the primary galaxy, rotationally supported dwarfs with gas fractions akin to those of observed dIrrs ( f _g_a_s ≳ 0.5), demonstrate a substantially enhanced likelihood and efficiency of transformation into dSphs relative to their collisionless ( f _g_a_s = 0) counterparts. We argue that the combination of ram-pressure stripping and SN winds causes the gas-rich dwarfs to respond more impulsively to tides, augmenting their transformation. When f _g_a_s ≳ 0.5, disky dwarfs on previously unfavorable low-eccentricity or large-pericenter orbits are still able to transform. On the widest orbits, the transformation is incomplete; the dwarfs retain significant rotational support, a relatively flat shape, and some gas, naturally resembling transition-type systems. We conclude that tidal stirring constitutes a prevalent evolutionary mechanism for shaping the structure of dwarf galaxies within the currently favored CDM cosmological paradigm.

Likelihood-Based Inference of B Cell Clonal Families.

Directory of Open Access Journals (Sweden)

Duncan K Ralph

2016-10-01

Full Text Available The human immune system depends on a highly diverse collection of antibody-making B cells. B cell receptor sequence diversity is generated by a random recombination process called "rearrangement" forming progenitor B cells, then a Darwinian process of lineage diversification and selection called "affinity maturation." The resulting receptors can be sequenced in high throughput for research and diagnostics. Such a collection of sequences contains a mixture of various lineages, each of which may be quite numerous, or may consist of only a single member. As a step to understanding the process and result of this diversification, one may wish to reconstruct lineage membership, i.e. to cluster sampled sequences according to which came from the same rearrangement events. We call this clustering problem "clonal family inference." In this paper we describe and validate a likelihood-based framework for clonal family inference based on a multi-hidden Markov Model (multi-HMM framework for B cell receptor sequences. We describe an agglomerative algorithm to find a maximum likelihood clustering, two approximate algorithms with various trade-offs of speed versus accuracy, and a third, fast algorithm for finding specific lineages. We show that under simulation these algorithms greatly improve upon existing clonal family inference methods, and that they also give significantly different clusters than previous methods when applied to two real data sets.

THE WHITE DWARF AGE OF NGC 2477

International Nuclear Information System (INIS)

Jeffery, Elizabeth J.; Von Hippel, Ted; DeGennaro, Steven; Jefferys, William H.; Van Dyk, David A.; Stein, Nathan

2011-01-01

We present deep photometric observations of the open cluster NGC 2477 using HST/WFPC2. By identifying seven cluster white dwarf candidates, we present an analysis of the white dwarf age of this cluster, using both the traditional method of fitting isochrones to the white dwarf cooling sequence, and by employing a new Bayesian statistical technique that has been developed by our group. This new method performs an objective, simultaneous model fit of the cluster and stellar parameters (namely, age, metallicity, distance, reddening, as well as individual stellar masses, mass ratios, and cluster membership) to the photometry. Based on this analysis, we measure a white dwarf age of 1.035 ± 0.054 ± 0.087 Gyr (uncertainties represent the goodness of model fits and discrepancy among models, respectively) in good agreement with the cluster's main-sequence turnoff age. This work is part of our ongoing work to calibrate main-sequence turnoff and white dwarf ages using open clusters, and to improve the precision of cluster ages to the ∼5% level.

Branes constrictions with White Dwarfs

International Nuclear Information System (INIS)

García-Aspeitia, Miguel A.

2015-01-01

We consider here a robust study of stellar dynamics for white dwarf stars with polytropic matter in the weak-field approximation using the Lane–Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze stability and compactness, in order to show whether it is possible to agree with the conventional wisdom of white dwarfs dynamics. Our results predict an average value of the brane tension of <λ>≳84.818 MeV 4 , with a standard deviation σ≃82.021 MeV 4 , which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining higher than cosmological results provided by nucleosynthesis among others

Topics in white dwarf astrophysics

International Nuclear Information System (INIS)

Hintzen, P.M.N.

1975-01-01

This study was designed to investigate the apparent deficiency, compared to theoretical predictions, of cool degenerate stars. Two approaches to the problem were employed: a spectroscopic survey designed to identify red degenerates, and a model atmospheres study of the spectroscopic and photometric differences between red dwarfs and red degenerate stars. On computed atmospheric models for white dwarfs at the temperatures under investigation. Line profiles obtained from these models indicate that degenerate stars with T/sub e/ approximately 6000 0 K and depleted surface metals would be extremely difficult to identify spectroscopically. Their hydrogen and calcium line profiles would strongly resemble those of classical sub-dwarfs. Three apparently degenerate stars whose spectral features match our predictions have been identified. These results indicate that the existence of the previously postulated deficiency of red degenerate stars is uncertain

Quality improvement in Vignoles through clonal selection

Science.gov (United States)

Our goal is to select an improved, loose-clustered clone of Vignoles that will contribute to an integrated approach to disease control. Clonal selection has historically proven useful in reducing cluster compactness through a variety of mechanisms, including decreased berry size, lengthening of the ...

Variable Stars in the M31 Dwarf Spheroidal Companion Cassiopeia

Science.gov (United States)

Pritzl, Barton J.; Armandroff, T. E.; Jacoby, G. H.; Da Costa, G. S.

2007-12-01

Dwarf spheroidal galaxies show very diverse star formation histories. For the Galactic dwarf spheroidal galaxies, a correlation exists between Galactocentric distance and the prominence of intermediate-age ( 2 - 10 Gyr) populations. To test whether this correlation exists for the M31 dwarf spheroidal galaxies, we observed the Cassiopeia (And VII) dwarf galaxy, which is one of the most distant M31 dwarf spheroidal galaxies. We will present the results of a variable star search using HST/ACS data, along with a preliminary color-magnitude diagram. From the RR Lyrae stars we can obtain an independent distance and metallicity estimate for the dwarf galaxy. These results will be compared to those found for the other M31 dwarf spheroidal galaxies.This research is supported in part by NASA through grant number GO-11081.11 from the Space Telescope Science Institute.

ROBO-AO M DWARF MULTIPLICITY SURVEY

Science.gov (United States)

Lamman, Claire; Berta-Thompson, Zachory; Baranec, Christoph; Law, Nicholas; Schonhut, Jessica

2018-01-01

We analyzed over 7,000 observations from Robo-AO’s field M dwarf survey taken on the 2.1m Kitt Peak telescope. Results will help determine the multiplicity fraction of M dwarfs as a function of primary mass, which is a crucial step towards understanding their evolution and formation mechanics. Through its robotic, laser-guided, and automated system, the Robo-AO instrument has yielded the largest adaptive-optics M dwarf survey to date. I developed a graphical user interface to quickly analyze this data. Initial data analysis included assessing data quality, checking the result from Robo-AO’s automatic reduction pipeline, and determining existence as well as the relative position of companions through a visual inspection. This program can be applied to other datasets and was successfully tested by re-analyzing observations from a separate Robo-AO survey. Following the preliminary results from this data analysis tool, further observations were done with the Keck II telescope by using its NIRC2 imager to follow up on ten select targets for the existence and physical association of companions. After a conservative initial cut for quality, 356 companions were found within 4” of a primary star out of 2,746 high quality Robo-AO M dwarf observations, including four triple systems. We will present a preliminary estimate for the multiplicity rate of wide M dwarf companions after accounting for observation limitations and the completeness of our search. Future research will yield insights into low-mass stellar formation and provide a database of nearby M dwarf multiples that will potentially assist ongoing and future surveys for planets around these stars, such as the NASA TESS mission.

[Chronologic analysis of clonal evolution in acquired aplastic anemia and sMDS].

Science.gov (United States)

Yoshizato, Tetsuichi

2016-04-01

Acquired aplastic anemia (AA) is a prototype of idiopathic bone marrow failure, which is caused by immune-mediated destruction of hematopoietic progenitors but is also characterized by frequent evolution to clonal myeloid disorders, such as myelodysplastic syndromes or acute myeloid leukemia. However, the chronological behavior of the clonality and its link to myelodysplastic syndrome or acute myeloid leukemia has not been fully explored. To define the clonality and its chronological behavior in AA, we performed targeted sequencing (N=439) in cases with AA. Somatic mutations were detected in 1/3 of our cases. Mutations were most frequently found in DNMT3A, followed by BCOR, PIGA and ASXL1. The prevalence of mutations increased with age. The clone sizes in DNMT3A and ASXL1 were prone to increase, whereas those of BCOR and PIGA were more likely to decrease or remain stable. Mutations in PIGA, BCOR and BCORL1 correlated with a better response to immunosuppressive therapy and more favorable survival. On the other hand, other mutations were associated with worse outcomes. The chronological dynamics of clonality showed marked variability and were not necessarily associated with prognosis.

[Lymphocytic Clonal Expansion in Adult Patients with Epstein-Barr Virus-Associated Lymphoproliferative Disease].

Science.gov (United States)

Zhong, Feng-Luan; Zhang, Hong-Yu; Zhang, Qian; Feng, Jia; Zhang, Wen-Li; Xu, Lei; Xu, Hai-Chan; Wen, Juan-Juan; Meng, Qing-Xiang

2017-12-01

To explore the lymphocytic clonal expansion in adult patients with Epstein-Barr virus-associated lymphoproliferative diseases (EBV+LPD), and to investigate the experimental methods for EBV+LPD cells so as to provide a more objective measure for the diagnosis, classification and prognosis in the early stage of this disease. Peripheral blood samples from 5 patients with EBV+LPD, 4 patients with adult infectious mononucleosis(IM) as negative control and 3 patients with acute NK-cell leukemia(ANKL) as positive control were collected. Prior to immunochemotherapy, viral loads and clonality were analysed by flow cytometry (FCM), T cell receptor gene rearrangement (TCR) was detected by real-time polymerase chain reaction (RT-PCR), and diversity of EB virus terminal repeat (EBV-TR) was detected by Southern blot. FCM showed only 1 case with clonal TCRVβ in 5 patients with EBV+LPD, TCR clonal expansion could be detected both in patients with IM(4 of 4) and 4 patients with EBV+LPD(4 of 5), Out of patients with EBV+LPD, 1 patient displayed a monoclonal band and 2 patients showed oligoclonal bands when detecting EBV-TR by southen blot. Detecting the diversity of EBV-TR by Southern blot may be the most objective way to reflex clonal transformation of EBV+LPD, which is of great benefit to the diagnosis, classification and prognosis in the early stage of this disease.

PCR-based clonality assessment in patients with lymphocytic ...

Indian Academy of Sciences (India)

study was to assess the clinical benefits of clonality testing with previously evaluated .... with the samples, negative controls containing no DNA were ..... 2003 Standardization and quality con- ... In Molecular cloning, a laboratory manual (ed.

Molecular characterization of barley 3H semi-dwarf genes.

Directory of Open Access Journals (Sweden)

Haobing Li

Full Text Available The barley chromosome 3H accommodates many semi-dwarfing genes. To characterize these genes, the two-rowed semi-dwarf Chinese barley landrace 'TX9425' was crossed with the Australian barley variety 'Franklin' to generate a doubled haploid (DH population, and major QTLs controlling plant height have been identified in our previous study. The major QTL derived from 'TX9425' was targeted to investigate the allelism of the semi-dwarf gene uzu in barley. Twelve sets of near-isogenic lines and a large NILF2 fine mapping population segregating only for the dwarfing gene from 'TX9425' were developed. The semi-dwarfing gene in 'TX9425' was located within a 2.8 cM region close to the centromere on chromosome 3H by fine mapping. Molecular cloning and sequence analyses showed that the 'TX9425'-derived allele contained a single nucleotide substitution from A to G at position 2612 of the HvBRI1 gene. This was apparently the same mutation as that reported in six-rowed uzu barley. Markers co-segregating with the QTL were developed from the sequence of the HvBRI1 gene and were validated in the 'TX9425'/'Franklin' DH population. The other major dwarfing QTL derived from the Franklin variety was distally located on chromosome 3HL and co-segregated with the sdw1 diagnostic marker hv20ox2. A third dwarfing gene, expressed only in winter-sown trials, was identified and located on chromosome 3HS. The effects and interactions of these dwarfing genes under different growing conditions are discussed. These results improve our understanding of the genetic mechanisms controlling semi-dwarf stature in barley and provide diagnostic markers for the selection of semi-dwarfness in barley breeding programs.

Bacterial clonal diagnostics as a tool for evidence-based empiric antibiotic selection.

Science.gov (United States)

Tchesnokova, Veronika; Avagyan, Hovhannes; Rechkina, Elena; Chan, Diana; Muradova, Mariya; Haile, Helen Ghirmai; Radey, Matthew; Weissman, Scott; Riddell, Kim; Scholes, Delia; Johnson, James R; Sokurenko, Evgeni V

2017-01-01

Despite the known clonal distribution of antibiotic resistance in many bacteria, empiric (pre-culture) antibiotic selection still relies heavily on species-level cumulative antibiograms, resulting in overuse of broad-spectrum agents and excessive antibiotic/pathogen mismatch. Urinary tract infections (UTIs), which account for a large share of antibiotic use, are caused predominantly by Escherichia coli, a highly clonal pathogen. In an observational clinical cohort study of urgent care patients with suspected UTI, we assessed the potential for E. coli clonal-level antibiograms to improve empiric antibiotic selection. A novel PCR-based clonotyping assay was applied to fresh urine samples to rapidly detect E. coli and the urine strain's clonotype. Based on a database of clonotype-specific antibiograms, the acceptability of various antibiotics for empiric therapy was inferred using a 20%, 10%, and 30% allowed resistance threshold. The test's performance characteristics and possible effects on prescribing were assessed. The rapid test identified E. coli clonotypes directly in patients' urine within 25-35 minutes, with high specificity and sensitivity compared to culture. Antibiotic selection based on a clonotype-specific antibiogram could reduce the relative likelihood of antibiotic/pathogen mismatch by ≥ 60%. Compared to observed prescribing patterns, clonal diagnostics-guided antibiotic selection could safely double the use of trimethoprim/sulfamethoxazole and minimize fluoroquinolone use. In summary, a rapid clonotyping test showed promise for improving empiric antibiotic prescribing for E. coli UTI, including reversing preferential use of fluoroquinolones over trimethoprim/sulfamethoxazole. The clonal diagnostics approach merges epidemiologic surveillance, antimicrobial stewardship, and molecular diagnostics to bring evidence-based medicine directly to the point of care.

Thermochemical modelling of brown dwarf discs

NARCIS (Netherlands)

Greenwood, A. J.; Kamp, I.; Waters, L. B. F. M.; Woitke, P.; Thi, W.-F.; Rab, Ch.; Aresu, G.; Spaans, M.

The physical properties of brown dwarf discs, in terms of their shapes and sizes, are still largely unexplored by observations. ALMA has by far the best capabilities to observe these discs in sub-mm CO lines and dust continuum, while also spatially resolving some discs. To what extent brown dwarf

White dwarfs in cataclysmic variables

International Nuclear Information System (INIS)

Sion, E.M.

1987-01-01

The physical properties and evolutionary state of the underlying white dwarfs in CVs are explored. Observations of 25 white dwarfs with effective temperature upper limits of 9000-75,000 K are discussed. Correlations between effective temperature, orbital period, accretion rate, and CV type with respect to the CV period gap are considered. Quasi-static and hydrodynamic evolutionary models are used to explain the surface temperature/luminosity distribution ratios. 42 references

The complete nucleotide sequence of the Barley yellow dwarf virus-RMV genome reveals it to be a new Polerovirus distantly related to other yellow dwarf viruses

Science.gov (United States)

The yellow dwarf viruses (YDVs) of the Luteoviridae family represent the most widespread group of cereal viruses worldwide. They include the Barley yellow dwarf viruses (BYDVs) of genus Luteovirus, the Cereal yellow dwarf viruses (CYDVs) and Wheat yellow dwarf virus (WYDV) of genus Polerovirus. All ...

Dusty Dwarfs Galaxies Occulting A Bright Background Spiral

Science.gov (United States)

Holwerda, Benne

2017-08-01

The role of dust in shaping the spectral energy distributions of low mass disk galaxies remains poorly understood. Recent results from the Herschel Space Observatory imply that dwarf galaxies contain large amounts of cool (T 20K) dust, coupled with very modest optical extinctions. These seemingly contradictory conclusions may be resolved if dwarfs harbor a variety of dust geometries, e.g., dust at larger galactocentric radii or in quiescent dark clumps. We propose HST observations of six truly occulting dwarf galaxies drawn from the Galaxy Zoo catalog of silhouetted galaxy pairs. Confirmed, true occulting dwarfs are rare as most low-mass disks in overlap are either close satellites or do not have a confirmed redshift. Dwarf occulters are the key to determining the spatial extent of dust, the small scale structure introduced by turbulence, and the prevailing dust attenuation law. The recent spectroscopic confirmation of bona-fide low mass occulting dwarfs offers an opportunity to map dust in these with HST. What is the role of dust in the SED of these dwarf disk galaxies? With shorter feedback scales, how does star-formation affect their morphology and dust composition, as revealed from their attenuation curve? The resolution of HST allows us to map the dust disks down to the fine scale structure of molecular clouds and multi-wavelength imaging maps the attenuation curve and hence dust composition in these disks. We therefore ask for 2 orbits on each of 6 dwarf galaxies in F275W, F475W, F606W, F814W and F125W to map dust from UV to NIR to constrain the attenuation curve.

Physiological values of some blood indicators in selected dwarf rabbit breeds

Directory of Open Access Journals (Sweden)

V. Šimek

2017-03-01

Full Text Available The aim of the present study was to evaluate the effect of breed on haematological and biochemical indicators in 3 dwarf rabbit breeds. In the experiment, 30 sexually intact dwarf rabbit females aged 6 mo were used. With the sole exception of white blood cells and haematocrit value, breed had the most significant effect on the majority of haematological indicators monitored. The red blood cell count was higher in the Dwarf Lop compared to the Netherland Dwarf (+1.91×1012 cells/L; P<0.05 and also the Teddy Dwarf (+1.32×1012 cells/L; P<0.05. For haemoglobin concentration, a higher value was found in the Netherland Dwarf than in the Teddy Dwarf (+39.29 g/L; P<0.05 and the Dwarf Lop (+26.36 g/L; P<0.05. For erythrocytic indicators, the highest values of mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration were found in the Netherland Dwarf. The breed had a significant effect on the urea and potassium values. A higher value of urea was recorded in the Dwarf Lop compared to the Teddy Dwarf (+1.56 mmol/L; P<0.05. For potassium, a higher value was found in the Netherland Dwarf compared to the Teddy Dwarf (+0.85 mmol/L; P<0.05. In addition, a significantly positive correlation (P<0.05 was found between the live weight of dwarf females and values of haematocrit (0.49, albumin (0.54, alanine aminotransferase (0.51, and aspartate aminotransferase (0.41, while a significantly negative correlation (P<0.05 was found between their live weight and values of triacylglycerols (–0.44, alkaline phosphatase (–0.38 and inorganic phosphorus (–0.52.

LOW CO LUMINOSITIES IN DWARF GALAXIES

International Nuclear Information System (INIS)

Schruba, Andreas; Walter, Fabian; Sandstrom, Karin; Leroy, Adam K.; Bigiel, Frank; Brinks, Elias; De Blok, W. J. G.; Kramer, Carsten; Rosolowsky, Erik; Schuster, Karl; Usero, Antonio; Weiss, Axel; Wiesemeyer, Helmut

2012-01-01

We present maps of 12 COJ = 2-1 emission covering the entire star-forming disks of 16 nearby dwarf galaxies observed by the IRAM HERACLES survey. The data have 13'' angular resolution, ∼250 pc at our average distance of D = 4 Mpc, and sample the galaxies by 10-1000 resolution elements. We apply stacking techniques to perform the first sensitive search for CO emission in dwarf galaxies outside the Local Group ranging from individual lines of sight, stacking over IR-bright regions of embedded star formation, and stacking over the entire galaxy. We detect five galaxies in CO with total CO luminosities of L CO2-1 = (3-28) × 10 6 K km s –1 pc 2 . The other 11 galaxies remain undetected in CO even in the stacked images and have L CO2-1 ∼ 6 K km s –1 pc 2 . We combine our sample of dwarf galaxies with a large sample of spiral galaxies from the literature to study scaling relations of L CO with M B and metallicity. We find that dwarf galaxies with metallicities of Z ≈ 1/2-1/10 Z ☉ have L CO of 2-4 orders of magnitude smaller than massive spiral galaxies and that their L CO per unit L B is 1-2 orders of magnitude smaller. A comparison with tracers of star formation (FUV and 24 μm) shows that L CO per unit star formation rate (SFR) is 1-2 orders of magnitude smaller in dwarf galaxies. One possible interpretation is that dwarf galaxies form stars much more efficiently: we argue that the low L CO /SFR ratio is due to the fact that the CO-to-H 2 conversion factor, α CO , changes significantly in low-metallicity environments. Assuming that a constant H 2 depletion time of τ dep = 1.8 Gyr holds in dwarf galaxies (as found for a large sample of nearby spirals) implies α CO values for dwarf galaxies with Z ≈ 1/2-1/10 Z ☉ that are more than one order of magnitude higher than those found in solar metallicity spiral galaxies. Such a significant increase of α CO at low metallicity is consistent with previous studies, in particular those of Local Group dwarf

General Relativistic Calculations for White Dwarf Stars

OpenAIRE

Mathew, Arun; Nandy, Malay K.

2014-01-01

The mass-radius relations for white dwarf stars are investigated by solving the Newtonian as well as Tolman-Oppenheimer-Volkoff (TOV) equations for hydrostatic equilibrium assuming the electron gas to be non-interacting. We find that the Newtonian limiting mass of $1.4562M_\\odot$ is modified to $1.4166M_\\odot$ in the general relativistic case for $^4_2$He (and $^{12}_{\\ 6}$C) white dwarf stars. Using the same general relativistic treatment, the critical mass for $^{56}_{26}$Fe white dwarf is ...

A STUDY OF THE DIVERSE T DWARF POPULATION REVEALED BY WISE

International Nuclear Information System (INIS)

Mace, Gregory N.; Wright, Edward L.; McLean, Ian S.; Davy Kirkpatrick, J.; Gelino, Christopher R.; Griffith, Roger L.; Mix, Katholeen; Beichman, Charles A.; Lowrance, Patrick J.; Cushing, Michael C.; Skrutskie, Michael F.; Marsh, Kenneth A.; Eisenhardt, Peter R.; Thompson, Maggie A.; Bailey, Vanessa; Hinz, Philip M.; Knox, Russell P.; Bloom, Joshua S.; Burgasser, Adam J.; Fortney, Jonathan J.

2013-01-01

We report the discovery of 87 new T dwarfs uncovered with the Wide-field Infrared Survey Explorer (WISE) and 3 brown dwarfs with extremely red near-infrared colors that exhibit characteristics of both L and T dwarfs. Two of the new T dwarfs are likely binaries with L7 ± 1 primaries and mid-type T secondaries. In addition, our follow-up program has confirmed 10 previously identified T dwarfs and 4 photometrically selected L and T dwarf candidates in the literature. This sample, along with the previous WISE discoveries, triples the number of known brown dwarfs with spectral types later than T5. Using the WISE All-Sky Source Catalog we present updated color-color and color-type diagrams for all the WISE-discovered T and Y dwarfs. Near-infrared spectra of the new discoveries are presented along with spectral classifications. To accommodate later T dwarfs we have modified the integrated flux method of determining spectral indices to instead use the median flux. Furthermore, a newly defined J-narrow index differentiates the early-type Y dwarfs from late-type T dwarfs based on the J-band continuum slope. The K/J indices for this expanded sample show that 32% of late-type T dwarfs have suppressed K-band flux and are blue relative to the spectral standards, while only 11% are redder than the standards. Comparison of the Y/J and K/J index to models suggests diverse atmospheric conditions and supports the possible re-emergence of clouds after the L/T transition. We also discuss peculiar brown dwarfs and candidates that were found not to be substellar, including two young stellar objects and two active galactic nuclei. The substantial increase in the number of known late-type T dwarfs provides a population that will be used to test models of cold atmospheres and star formation. The coolest WISE-discovered brown dwarfs are the closest of their type and will remain the only sample of their kind for many years to come.

Integration Site and Clonal Expansion in Human Chronic Retroviral Infection and Gene Therapy

Science.gov (United States)

Niederer, Heather A.; Bangham, Charles R. M.

2014-01-01

Retroviral vectors have been successfully used therapeutically to restore expression of genes in a range of single-gene diseases, including several primary immunodeficiency disorders. Although clinical trials have shown remarkable results, there have also been a number of severe adverse events involving malignant outgrowth of a transformed clonal population. This clonal expansion is influenced by the integration site profile of the viral integrase, the transgene expressed, and the effect of the viral promoters on the neighbouring host genome. Infection with the pathogenic human retrovirus HTLV-1 also causes clonal expansion of cells containing an integrated HTLV-1 provirus. Although the majority of HTLV-1-infected people remain asymptomatic, up to 5% develop an aggressive T cell malignancy. In this review we discuss recent findings on the role of the genomic integration site in determining the clonality and the potential for malignant transformation of cells carrying integrated HTLV-1 or gene therapy vectors, and how these results have contributed to the understanding of HTLV-1 pathogenesis and to improvements in gene therapy vector safety. PMID:25365582

Branes constrictions with White Dwarfs

Energy Technology Data Exchange (ETDEWEB)

García-Aspeitia, Miguel A., E-mail: aspeitia@fisica.uaz.edu.mx [Consejo Nacional de Ciencia y Tecnología, Av, Insurgentes Sur 1582, Colonia Crédito Constructor, Del. Benito Juárez, C.P. 03940, Mexico, D.F. (Mexico); Unidad Académica de Física, Universidad Autónoma de Zacatecas, Calzada Solidaridad esquina con Paseo a la Bufa S/N, C.P. 98060, Zacatecas (Mexico)

2015-11-06

We consider here a robust study of stellar dynamics for white dwarf stars with polytropic matter in the weak-field approximation using the Lane–Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze stability and compactness, in order to show whether it is possible to agree with the conventional wisdom of white dwarfs dynamics. Our results predict an average value of the brane tension of <λ>≳84.818 MeV{sup 4}, with a standard deviation σ≃82.021 MeV{sup 4}, which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining higher than cosmological results provided by nucleosynthesis among others.

Branes constrictions with White Dwarfs

Energy Technology Data Exchange (ETDEWEB)

Garcia-Aspeitia, Miguel A. [Consejo Nacional de Ciencia y Tecnologia, Mexico (Mexico); Unidad Academica de Fisica, Universidad Autonoma de Zacatecas (Mexico)

2015-11-15

We consider here a robust study of stellar dynamics for white dwarf stars with polytropic matter in the weak-field approximation using the Lane-Emden equation from the brane-world scenario. We also derive an analytical solution to the nonlocal energy density and show the behavior and sensitivity of these stars to the presence of extra dimensions. Similarly, we analyze stability and compactness, in order to show whether it is possible to agree with the conventional wisdom of white dwarfs dynamics. Our results predict an average value of the brane tension of left angle λ right angle >or similar 84.818 MeV{sup 4}, with a standard deviation σ ≅ 82.021 MeV{sup 4}, which comes from a sample of dwarf stars, being weaker than other astrophysical observations but remaining higher than cosmological results provided by nucleosynthesis among others. (orig.)

Benchmark ultra-cool dwarfs in widely separated binary systems

Directory of Open Access Journals (Sweden)

Jones H.R.A.

2011-07-01

Full Text Available Ultra-cool dwarfs as wide companions to subgiants, giants, white dwarfs and main sequence stars can be very good benchmark objects, for which we can infer physical properties with minimal reference to theoretical models, through association with the primary stars. We have searched for benchmark ultra-cool dwarfs in widely separated binary systems using SDSS, UKIDSS, and 2MASS. We then estimate spectral types using SDSS spectroscopy and multi-band colors, place constraints on distance, and perform proper motions calculations for all candidates which have sufficient epoch baseline coverage. Analysis of the proper motion and distance constraints show that eight of our ultra-cool dwarfs are members of widely separated binary systems. Another L3.5 dwarf, SDSS 0832, is shown to be a companion to the bright K3 giant η Cancri. Such primaries can provide age and metallicity constraints for any companion objects, yielding excellent benchmark objects. This is the first wide ultra-cool dwarf + giant binary system identified.

Implications of the dwarfs spheroidal galaxy mass-metallicity relation

International Nuclear Information System (INIS)

Smith, G.H.

1985-01-01

The properties of the mass-metallicity relation among dwarf spheroidal galaxies are discussed in terms of a model which assumes that the internal chemical evolution of the dwarf spheroidals was promoted by supernova activity. The model can be used to explain the observed dwarf spheroidal mass-metallicity relation assuming the present mass of these systems M sub s is proportional to their initial masses M as M sub s varies according to a power-law index of exp 7/4. It is inferred from the power-law dependence of M on the proto-cloud radius that the most massive dwarf spheroids were formed from the densest clouds. The observed slope of the mass-metallicity relation for dwarf spheroidal galaxies is found to be significantly different from theoretical estimates of this slope for elliptical galaxies. It is suggested that the difference may imply that spheroidal dwarfs and elliptical galaxies had different formation histories, confirming Kormendy's (1985) observations of differences in the brightness and luminosity trends. 54 references

Genetic and agronomic evaluation of induced semi-dwarf mutants of rice

International Nuclear Information System (INIS)

Rutger, J.N.

1984-01-01

Induced semi-dwarf mutants have played an important role in California's rapid shift from nearly all tall rice varieties in 1978 to nearly all semi-dwarf varieties at present. In 1981 over half of the California rice area was planted with semi-dwarf varieties carrying the induced mutant semi-dwarfing gene sd 1 , while much of the other half was planted to a variety deriving its semi-dwarfism from IR8. The sd 1 mutant is allelic to the major semi-dwarfing gene in DGWG and IR8. Current objectives are to determine the inheritance of new semi-dwarf mutants, including allelism tests with sd 1 , and to evaluate the agronomic potential of nonallelic sources and of double-dwarfs. To date semi-dwarf mutants from 10 varieties have been partially or completely evaluated. At least three nonallelic semi-dwarfing genes, sd 1 , sd 2 , and sd 4 , have been described. Rather than attempt to determine all possible allelic relationships of new mutants, crosses are being made only to the reference sd 1 source, since sd 1 , still seems to be the most productive semi-dwarfing gene source. However, nonallelic semi-dwarf mutants in the varieties M5 and Labelle may be useful if genetic vulnerability from widespread usage of the sd 1 source becomes a problem. (author)

ON THE EVOLUTION OF MAGNETIC WHITE DWARFS

Energy Technology Data Exchange (ETDEWEB)

Tremblay, P.-E. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Fontaine, G.; Brassard, P. [Département de Physique, Université de Montréal, C. P. 6128, Succursale Centre-Ville, Montréal, QC H3C 3J7 (Canada); Freytag, B. [Department of Physics and Astronomy at Uppsala University, Regementsvägen 1, Box 516, SE-75120 Uppsala (Sweden); Steiner, O. [Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, D-79104 Freiburg (Germany); Ludwig, H.-G. [Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Königstuhl 12, D-69117 Heidelberg (Germany); Steffen, M. [Leibniz-Institut für Astrophysik Potsdam, An der Sternwarte 16, D-14482 Potsdam (Germany); Wedemeyer, S., E-mail: tremblay@stsci.edu [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)

2015-10-10

We present the first radiation magnetohydrodynamic simulations of the atmosphere of white dwarf stars. We demonstrate that convective energy transfer is seriously impeded by magnetic fields when the plasma-β parameter, the thermal-to-magnetic-pressure ratio, becomes smaller than unity. The critical field strength that inhibits convection in the photosphere of white dwarfs is in the range B = 1–50 kG, which is much smaller than the typical 1–1000 MG field strengths observed in magnetic white dwarfs, implying that these objects have radiative atmospheres. We have employed evolutionary models to study the cooling process of high-field magnetic white dwarfs, where convection is entirely suppressed during the full evolution (B ≳ 10 MG). We find that the inhibition of convection has no effect on cooling rates until the effective temperature (T{sub eff}) reaches a value of around 5500 K. In this regime, the standard convective sequences start to deviate from the ones without convection due to the convective coupling between the outer layers and the degenerate reservoir of thermal energy. Since no magnetic white dwarfs are currently known at the low temperatures where this coupling significantly changes the evolution, the effects of magnetism on cooling rates are not expected to be observed. This result contrasts with a recent suggestion that magnetic white dwarfs with T{sub eff} ≲ 10,000 K cool significantly slower than non-magnetic degenerates.

Dwarf mistletoes: Biology, pathology, and systematics

Science.gov (United States)

Frank G. Hawksworth; Delbert Wiens

1996-01-01

Arceuthobium (dwarf mistletoes), a well defined but morphologically reduced genus of the family Viscaceae, is parasitic on Pinaceae in the Old and New Worlds and on Cupressaceae in the Old World. Although conifer forests in many parts of the Northern Hemisphere are infested with dwarf mistletoes, those most commonly infested are in western North...

Influência de porta-enxertos na resistência de mudas de cajueiro ao estresse salino Influence of rootstocks on the resistance of cashew plantlets to salt stress

Directory of Open Access Journals (Sweden)

Sérgio Luiz Ferreira-Silva

2009-04-01

Full Text Available O objetivo deste trabalho foi avaliar a influência de porta-enxertos na resistência de mudas de cajueiro (Anacardium occidentale L. à salinidade. As mudas foram obtidas pela enxertia do clone BRS 226 sobre os porta-enxertos CAPI 4, CCP 09 e BRS 226. Foram expostas a meio hidropônico sem NaCl (controle ou com NaCl 200 mM (tratamento salino, sob condições controladas de temperatura, umidade e luminosidade, durante 12 dias. O delineamento foi o inteiramente casualizado, em esquema fatorial 3x2 (três combinações de enxerto/porta-enxerto e duas concentrações de NaCl, com quatro repetições. Foram determinados a concentração de Na+, Cl-, K+ e solutos orgânicos e os sintomas visuais de toxicidade nas folhas. Os conteúdos de Na+ e Cl-, a relação K+/Na+ e as concentrações de aminoácidos e de prolina livres nas folhas tiveram relação direta com os sintomas visuais de toxicidade. Os porta-enxertos CAPI 4, CCP 09 e BRS 226 foram classificados como sensível, intermediário e resistente à salinidade elevada, respectivamente. Essa variação foi decorrente da influência do porta-enxerto na partição do Na+ e do Cl-.The aim of this work was to evaluate the influence of cashew (Anacardium occidentale L. rootstocks on salt resistance in grafted plantlets. The plantlets were obtained by grafting the BRS 226 scion on CAPI 4, CCP 09 and BRS 226 rootstocks, and were exposed to nutrient solution without NaCl (control or with 200 mM NaCl (salt treatment in hydroponics under controlled temperature, humidity, and luminosity conditions during 12 days. The experimental design was a completely randomized in factorial arrangement 3x2 (three scion/rootstock combinations, two NaCl concentrations with four replicates. Na+, Cl-, K+ and organic solute concentrations and toxicity symptoms on leaves were determined. Na+ and Cl- contents, the K+/Na+ ratio and the free amino acid and proline concentrations in leaves were directly related to the visual

A dwarf wheat mutant is associated with increased drought ...

African Journals Online (AJOL)

... was significantly higher than Jingdong 6. Most of the s-dwarf seedlings survived in recovering experiement after water loss. The stalk of s-dwarf seedling also showed reduced gravitropism. This is the first report about a new dwarf wheat mutant associated with increased drought resistance and altered stalk gravitropism.

Ages of white dwarf-red subdwarf systems

Directory of Open Access Journals (Sweden)

Hektor Monteiro

2006-01-01

Full Text Available We provide the first age estimates for two recently discovered white dwarf-red subdwarf systems, LHS 193AB and LHS 300AB. These systems provide a new opportunity for linking the reliable age estimates for the white dwarfs to the (measurable metallicities of the red subdwarfs. We have obtained precise photometry in the VJRKCIKCJH bands and spectroscopy covering from 6,000°A to 9,000°A (our spectral coveragefor the two new systems, as well as for a comparison white dwarfmain sequence red dwarf system, GJ 283 AB. Using model grids, we estimate the cooling age as well as temperature, surface gravity, mass, progenitor mass and total lifetimes of the white dwarfs. The results indicate that the two new systems are probably ancient thick disk objects with ages of at least 6-9 gigayears (Gyr.

Double Degenerates among DA white dwarfs

International Nuclear Information System (INIS)

Bragaglia, A.; Greggio, L.; Renzini, A.; D'odorico, S.

1990-01-01

The results of a spectroscopic survey of catalog white dwarfs in search of radial velocity variations indicative of a binary motion are reported. In a sample of 54 DA white dwarfs, one Double Degenerate (DD) system with a period of 1.15 days (the shortest period DD system yet discovered) is found. Two other excellent and two good DD candidates, and two white dwarf + red dwarf pairs were also found. If all the candidates should be confirmed, this would indicate a frequency of about 13 percent of interacting binaries in an unbiased sample of evolved stars, with a DD frequency of about 10 percent. These results suggest fairly large values for the common-envelope parameter alpha, implying that a source of energy other than orbital may be required to eject the envelope during common-envelope events. Finally, in combination with previous evidence our result implies that DDs with WD components of the DA variety are unlikely to be the precursors of Type I supernovae, but DDs with non-DA components remain very attractive candidates. 20 refs

Clonal diversity and fine-scale genetic structure in a high andean treeline population

Czech Academy of Sciences Publication Activity Database

Peng, Y.; Macek, P.; Macková, Jana; Romoleroux, K.; Hensen, I.

2015-01-01

Roč. 47, č. 1 (2015), s. 59-65 ISSN 0006-3606 Grant - others:GA AV ČR(CZ) IAA601110702; GA MŠk(CZ) LM2010009 Program:IA Institutional support: RVO:60077344 Keywords : AFLP * clonal diversity * clonal propagation * fine-scale genetic structure * Polylepis reticulata * treeline Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.944, year: 2015

Variation of functional clonal traits along elevation in two fern species

International Nuclear Information System (INIS)

Song, Y.B.; Chen, L.Y.; Xiong, W.

2015-01-01

Phenotypical plasticity is generally considered among adaptive strategies by which plants can cope with environmental variation in space and time. Although much is known about plasticity in seed plants in terms of functional clonal traits while little is known about ferns. Variation of functional clonal traits of two ferns Dicranopteris dichotoma and Diplopterygium glaucum among plots differing in elevation in a subtropical evergreen broad-leaved forest in southern China was investigated. Along with elevation increasing the two fern species showed similar variation pattern of functional clonal traits: stable spacer length, increasing specific spacer length and decreasing spacer weight per ramet and specific spacer weight. The two ferns species had similar variation pattern of ramet performance traits but different variation pattern of ramet population properties. These results suggest an evolutionary trade-off between functions of foraging for and storing of resources in the two ferns, with a functional preference for the foraging in response to environmental change. (author)

Evaluation on selected dwarf and semidwarf mutants of upland rice

International Nuclear Information System (INIS)

Riyanti Sumanggono, A.M.

1984-01-01

Seratus malam local upland rice variety was irradiated with gamma-rays at doses of O.1, 0.2, 0.3, 0.4 and 0.5 kGy. Observation of radiation effect was carried out on root and shoot length of M 1 seedlings; plant height, panicle length and number of tiller and seed sterility in M 1 plants. Selection for dwarf and semi-dwarf characteristics were done in M 2 plants, and selected again in M 3 . Observation on radiation effect indicated that 'Seratus Malam' seems to be more resistant than the lowland rice varieties. Increasing doses of radiation caused increasing frequency of chlorophyll mutations as well as chlorophyll mutants. Whereas, selection of dwarf or semi-dwarf in M 2 plants seems that mutant and mutation frequencies decreased as the dose increased. Dose of 0.2 kGy was suitable for selection of dwarf or semi-dwarf plants. Plant height could be influenced by environmental condition. Many of the selected M 2 plants were not really dwarf or semi-dwarf mutants. M 3 evaluation of the selected M 2 plants was really beneficial in the mutant selection. (author)

Brown dwarfs in retrogradely precessing cataclysmic variables?

Directory of Open Access Journals (Sweden)

Martin E.L.

2011-07-01

Full Text Available We compare Smoothed Particle Hydrodynamic simulations of retrogradely precessing accretion disks that have a white dwarf primary and a main sequence secondary with observational data and with theory on retrograde precession via tidal torques like those by the Moon and the Sun on the Earth [1, 2]. Assuming the primary does not accrete much of the mass lost from the secondary, we identify the theoretical low mass star/brown dwarf boundary. We find no observational candidates in our study that could qualify as brown dwarfs.

Population demographics for the federally endangered dwarf wedgemussel

Science.gov (United States)

Galbraith, Heather S.; Lellis, William A.; Cole, Jeffrey C.; Blakeslee, Carrie J.; St. John White, Barbara

2016-01-01

The dwarf wedgemussel, Alasmidonta heterodon, is a federally endangered freshwater mussel species inhabiting several Atlantic Slope rivers. Studies on population demographics of this species are necessary for status assessment and directing recovery efforts. We conducted qualitative and quantitative surveys for dwarf wedgemussel in the mainstem Delaware River and in four of its tributaries (Big Flat Brook, Little Flat Brook, Neversink River, and Paulinskill River). Population range, relative abundance, size, size structure, and sex ratio were quantified within each river. Total dwarf wedgemussel population size for the surveyed rivers in the Delaware Basin was estimated to be 14,432 individuals (90% confidence limits, 7,961-26,161). Our results suggest that the historically robust Neversink River population has declined, but that this population persists and substantial populations remain in other tributaries. Sex ratios were generally female-biased, and small individuals (Dwarf wedgemussel was most often found at the surface of the sediment (not buried below) in shallow quadrats (dwarf wedgemussel viability within the Delaware River Basin.

Diverse cellular architecture of atherosclerotic plaque derives from clonal expansion of a few medial SMCs

DEFF Research Database (Denmark)

Jacobsen, Kevin; Lund, Marie Bek; Shim, Jeong

2017-01-01

Fibrous cap smooth muscle cells (SMCs) protect atherosclerotic lesions from rupturing and causing thrombosis, while other plaque SMCs may have detrimental roles in plaque development. To gain insight into recruitment of different plaque SMCs, we mapped their clonal architecture in aggregation...... in the cap and heterogeneous ACTA2– SMCs in the plaque interior, including chondrocyte-like cells and cells with intracellular lipid and crystalline material. Fibrous cap SMCs were invariably arranged in endothelium-aligned clonal sheets, confirming results in the aggregation chimeras. Analysis of the clonal...

Emergence of clonal hematopoiesis in the majority of patients with acquired aplastic anemia.

Science.gov (United States)

Babushok, Daria V; Perdigones, Nieves; Perin, Juan C; Olson, Timothy S; Ye, Wenda; Roth, Jacquelyn J; Lind, Curt; Cattier, Carine; Li, Yimei; Hartung, Helge; Paessler, Michele E; Frank, Dale M; Xie, Hongbo M; Cross, Shanna; Cockroft, Joshua D; Podsakoff, Gregory M; Monos, Dimitrios; Biegel, Jaclyn A; Mason, Philip J; Bessler, Monica

2015-04-01

Acquired aplastic anemia (aAA) is a nonmalignant disease caused by autoimmune destruction of early hematopoietic cells. Clonal hematopoiesis is a late complication, seen in 20-25% of older patients. We hypothesized that clonal hematopoiesis in aAA is a more general phenomenon, which can arise early in disease, even in younger patients. To evaluate clonal hematopoiesis in aAA, we used comparative whole exome sequencing of paired bone marrow and skin samples in 22 patients. We found somatic mutations in 16 patients (72.7%) with a median disease duration of 1 year; of these, 12 (66.7%) were patients with pediatric-onset aAA. Fifty-eight mutations in 51 unique genes were found primarily in pathways of immunity and transcriptional regulation. Most frequently mutated was PIGA, with seven mutations. Only two mutations were in genes recurrently mutated in myelodysplastic syndrome. Two patients had oligoclonal loss of the HLA alleles, linking immune escape to clone emergence. Two patients had activating mutations in key signaling pathways (STAT5B (p.N642H) and CAMK2G (p.T306M)). Our results suggest that clonal hematopoiesis in aAA is common, with two mechanisms emerging-immune escape and increased proliferation. Our findings expand conceptual understanding of this nonneoplastic blood disorder. Future prospective studies of clonal hematopoiesis in aAA will be critical for understanding outcomes and for designing personalized treatment strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

METALLICITY AND TEMPERATURE INDICATORS IN M DWARF K-BAND SPECTRA: TESTING NEW AND UPDATED CALIBRATIONS WITH OBSERVATIONS OF 133 SOLAR NEIGHBORHOOD M DWARFS

Energy Technology Data Exchange (ETDEWEB)

Rojas-Ayala, Barbara [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States); Covey, Kevin R.; Lloyd, James P. [Department of Astronomy, Cornell University, 122 Sciences Drive, Ithaca, NY 14853 (United States); Muirhead, Philip S., E-mail: babs@amnh.org [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States)

2012-04-01

We present K-band spectra for 133 nearby (d < 33 ps) M dwarfs, including 18 M dwarfs with reliable metallicity estimates (as inferred from an FGK type companion), 11 M dwarf planet hosts, more than 2/3 of the M dwarfs in the northern 8 pc sample, and several M dwarfs from the LSPM catalog. From these spectra, we measure equivalent widths of the Ca and Na lines, and a spectral index quantifying the absorption due to H{sub 2}O opacity (the H{sub 2}O-K2 index). Using empirical spectral type standards and synthetic models, we calibrate the H{sub 2}O-K2 index as an indicator of an M dwarf's spectral type and effective temperature. We also present a revised relationship that estimates the [Fe/H] and [M/H] metallicities of M dwarfs from their Na I, Ca I, and H{sub 2}O-K2 measurements. Comparisons to model atmosphere provide a qualitative validation of our approach, but also reveal an overall offset between the atomic line strengths predicted by models as compared to actual observations. Our metallicity estimates also reproduce expected correlations with Galactic space motions and H{alpha} emission line strengths, and return statistically identical metallicities for M dwarfs within a common multiple system. Finally, we find systematic residuals between our H{sub 2}O-based spectral types and those derived from optical spectral features with previously known sensitivity to stellar metallicity, such as TiO, and identify the CaH1 index as a promising optical index for diagnosing the metallicities of near-solar M dwarfs.

Clonality, virulence and antimicrobial resistance of enteroaggregative Escherichia coli from Mirzapur, Bangladesh.

Science.gov (United States)

Chattaway, Marie Anne; Day, Michaela; Mtwale, Julia; White, Emma; Rogers, James; Day, Martin; Powell, David; Ahmad, Marwa; Harris, Ross; Talukder, Kaisar Ali; Wain, John; Jenkins, Claire; Cravioto, Alejandro

2017-10-01

This study investigates the virulence and antimicrobial resistance in association with common clonal complexes (CCs) of enteroaggregative Escherichia coli (EAEC) isolated from Bangladesh. The aim was to determine whether specific CCs were more likely to be associated with putative virulence genes and/or antimicrobial resistance. The presence of 15 virulence genes (by PCR) and susceptibility to 18 antibiotics were determined for 151 EAEC isolated from cases and controls during an intestinal infectious disease study carried out between 2007-2011 in the rural setting of Mirzapur, Bangladesh (Kotloff KL, Blackwelder WC, Nasrin D, Nataro JP, Farag TH et al.Clin Infect Dis 2012;55:S232-S245). These data were then analysed in the context of previously determined serotypes and clonal complexes defined by multi-locus sequence typing. Overall there was no association between the presence of virulence or antimicrobial resistance genes in isolates of EAEC from cases versus controls. However, when stratified by clonal complex (CC) one CC associated with cases harboured more virulence factors (CC40) and one CC harboured more resistance genes (CC38) than the average. There was no direct link between the virulence gene content and antibiotic resistance. Strains within a single CC had variable virulence and resistance gene content indicating independent and multiple gene acquisitions over time. In Bangladesh, there are multiple clonal complexes of EAEC harbouring a variety of virulence and resistance genes. The emergence of two of the most successful clones appeared to be linked to either increased virulence (CC40) or antimicrobial resistance (CC38), but increased resistance and virulence were not found in the same clonal complexes.

Bacterial clonal diagnostics as a tool for evidence-based empiric antibiotic selection.

Directory of Open Access Journals (Sweden)

Veronika Tchesnokova

Full Text Available Despite the known clonal distribution of antibiotic resistance in many bacteria, empiric (pre-culture antibiotic selection still relies heavily on species-level cumulative antibiograms, resulting in overuse of broad-spectrum agents and excessive antibiotic/pathogen mismatch. Urinary tract infections (UTIs, which account for a large share of antibiotic use, are caused predominantly by Escherichia coli, a highly clonal pathogen. In an observational clinical cohort study of urgent care patients with suspected UTI, we assessed the potential for E. coli clonal-level antibiograms to improve empiric antibiotic selection. A novel PCR-based clonotyping assay was applied to fresh urine samples to rapidly detect E. coli and the urine strain's clonotype. Based on a database of clonotype-specific antibiograms, the acceptability of various antibiotics for empiric therapy was inferred using a 20%, 10%, and 30% allowed resistance threshold. The test's performance characteristics and possible effects on prescribing were assessed. The rapid test identified E. coli clonotypes directly in patients' urine within 25-35 minutes, with high specificity and sensitivity compared to culture. Antibiotic selection based on a clonotype-specific antibiogram could reduce the relative likelihood of antibiotic/pathogen mismatch by ≥ 60%. Compared to observed prescribing patterns, clonal diagnostics-guided antibiotic selection could safely double the use of trimethoprim/sulfamethoxazole and minimize fluoroquinolone use. In summary, a rapid clonotyping test showed promise for improving empiric antibiotic prescribing for E. coli UTI, including reversing preferential use of fluoroquinolones over trimethoprim/sulfamethoxazole. The clonal diagnostics approach merges epidemiologic surveillance, antimicrobial stewardship, and molecular diagnostics to bring evidence-based medicine directly to the point of care.

Global and photospheric physical parameters of active dwarf stars

International Nuclear Information System (INIS)

Pettersen, B.R.

1983-01-01

Physical parameters (temperature, luminosity, radius, mass and chemical abundance) of the photospheres of red dwarf flare stars and spotted stars are determined for quiescent conditions. The interrelations between these quantities are compared to the results of theoretical investigation for low mass stars. The evolutionary state of flare stars is discussed. Observational results from spectroscopic and photometric methods to determine the rotation of active dwarfs are reviewed. The possibilities of global oscillations in dwarf stars are considered and preliminary results of a photometric search for oscillation in red dwarf luminosities are presented. (orig.)

Analysis of the clonal repertoire of gene-corrected cells in gene therapy.

Science.gov (United States)

Paruzynski, Anna; Glimm, Hanno; Schmidt, Manfred; Kalle, Christof von

2012-01-01

Gene therapy-based clinical phase I/II studies using integrating retroviral vectors could successfully treat different monogenetic inherited diseases. However, with increased efficiency of this therapy, severe side effects occurred in various gene therapy trials. In all cases, integration of the vector close to or within a proto-oncogene contributed substantially to the development of the malignancies. Thus, the in-depth analysis of integration site patterns is of high importance to uncover potential clonal outgrowth and to assess the safety of gene transfer vectors and gene therapy protocols. The standard and nonrestrictive linear amplification-mediated PCR (nrLAM-PCR) in combination with high-throughput sequencing exhibits technologies that allow to comprehensively analyze the clonal repertoire of gene-corrected cells and to assess the safety of the used vector system at an early stage on the molecular level. It enables clarifying the biological consequences of the vector system on the fate of the transduced cell. Furthermore, the downstream performance of real-time PCR allows a quantitative estimation of the clonality of individual cells and their clonal progeny. Here, we present a guideline that should allow researchers to perform comprehensive integration site analysis in preclinical and clinical studies. Copyright © 2012 Elsevier Inc. All rights reserved.

Distribution of clonal growth forms in wetlands

Czech Academy of Sciences Publication Activity Database

Sosnová, Monika; van Diggelen, R.; Klimešová, Jitka

2010-01-01

Roč. 92, č. 1 (2010), s. 33-39 ISSN 0304-3770 R&D Projects: GA ČR GD206/08/H044 Institutional research plan: CEZ:AV0Z60050516 Keywords : clonal growth organ * the Netherlands * wetland plant community Subject RIV: EF - Botanics Impact factor: 2.087, year: 2010

The mass dependence of dwarf satellite galaxy quenching

International Nuclear Information System (INIS)

Slater, Colin T.; Bell, Eric F.

2014-01-01

We combine observations of the Local Group with data from the NASA-Sloan Atlas to show the variation in the quenched fraction of satellite galaxies from low-mass dwarf spheroidals and dwarf irregulars to more massive dwarfs similar to the Magellanic Clouds. While almost all of the low-mass (M * ≲ 10 7 M ☉ ) dwarfs are quenched, at higher masses the quenched fraction decreases to approximately 40%-50%. This change in the quenched fraction is large and suggests a sudden change in the effectiveness of quenching that correlates with satellite mass. We combine this observation with models of satellite infall and ram pressure stripping to show that the low-mass satellites must quench within 1-2 Gyr of pericenter passage to maintain a high quenched fraction, but that many more massive dwarfs must continue to form stars today even though they likely fell into their host >5 Gyr ago. We also characterize how the susceptibility of dwarfs to ram pressure must vary as a function of mass if it is to account for the change in quenched fractions. Though neither model predicts the quenching effectiveness a priori, this modeling illustrates the physical requirements that the observed quenched fractions place on possible quenching mechanisms.

Robo-AO M Dwarf Multiplicity Survey

Science.gov (United States)

Lamman, Claire; Baranec, Christoph; Berta-Thompson, Zachory K.; Law, Nicholas M.; Ziegler, Carl; Schonhut-Stasik, Jessica

2018-06-01

We analyzed close to 7,000 observations from Robo-AO’s field M dwarf survey taken on the 2.1m Kitt Peak telescope. Results will help determine the total multiplicity fraction and multiplicity functions of M dwarfs, which are crucial steps towards understanding their evolution and formation mechanics. Through its robotic, laser-guided, and automated system, the Robo-AO instrument has yielded the largest adaptive-optics M dwarf survey to date. I developed a graphical user interface to quickly analyze this data. Initial data analysis included assessing data quality, checking the result from Robo-AO’s automatic reduction pipeline, and determining existence as well as the relative position of companions through a visual inspection. This program can be applied to other datasets and was successfully tested by re-analyzing observations from a separate Robo-AO survey. After a conservative initial cut for quality, over 350 companions were found within 4” of a primary star out of 2,746 high quality Robo-AO M dwarf observations, including four triple systems. Further observations were done with the Keck II telescope by using its NIRC2 imager to follow up on ten select targets for the existence and physical association of companions. Future research will yield insights into low-mass stellar formation and provide a database of nearby M dwarf multiples that will potentially assist ongoing and future surveys for planets around these stars, such as the NASA TESS mission.

Serendipitous discovery of a dwarf Nova in the Kepler field near the G dwarf KIC 5438845

International Nuclear Information System (INIS)

Brown, Alexander; Ayres, Thomas R.; Neff, James E.; Wells, Mark A.; Kowalski, Adam; Hawley, Suzanne; Berdyugina, Svetlana; Harper, Graham M.; Korhonen, Heidi; Piskunov, Nikolai; Saar, Steven; Walkowicz, Lucianne

2015-01-01

The Kepler satellite provides a unique window into stellar temporal variability by observing a wide variety of stars with multi-year, near-continuous, high precision, optical photometric time series. While most Kepler targets are faint stars with poorly known physical properties, many unexpected discoveries should result from a long photometric survey of such a large area of sky. During our Kepler Guest Observer programs that monitored late-type stars for starspot and flaring variability, we discovered a previously unknown dwarf nova that lies within a few arcseconds of the mid-G dwarf star KIC 5438845. This dwarf nova underwent nine outbursts over a 4 year time span. The two largest outbursts lasted ∼17–18 days and show strong modulations with a 110.8 minute period and a declining amplitude during the outburst decay phase. These properties are characteristic of an SU UMa-type cataclysmic variable. By analogy with other dwarf nova light curves, we associate the 110.8 minute (1.847 hr) period with the superhump period, close to but slightly longer than the orbital period of the binary. No precursor outbursts are seen before the super-outbursts and the overall super-outburst morphology corresponds to Osaki and Meyer “Case B” outbursts, which are initiated when the outer edge of the disk reaches the tidal truncation radius. “Case B” outbursts are rare within the Kepler light curves of dwarf novae. The dwarf nova is undergoing relatively slow mass transfer, as evidenced by the long intervals between outbursts, but the mass transfer rate appears to be steady, because the smaller “normal” outbursts show a strong correlation between the integrated outburst energy and the elapsed time since the previous outburst. At super-outburst maximum the system was at V ∼ 18, but in quiescence it is fainter than V ∼ 22, which will make any detailed quiescent follow-up of this system difficult.

K2 Ultracool Dwarfs Survey. III. White Light Flares Are Ubiquitous in M6-L0 Dwarfs

Science.gov (United States)

Paudel, Rishi R.; Gizis, John E.; Mullan, D. J.; Schmidt, Sarah J.; Burgasser, Adam J.; Williams, Peter K. G.; Berger, Edo

2018-05-01

We report the white light flare rates for 10 ultracool dwarfs using Kepler K2 short-cadence data. Among our sample stars, two have spectral type M6, three are M7, three are M8, and two are L0. Most of our targets are old low-mass stars. We identify a total of 283 flares in all of the stars in our sample, with Kepler energies in the range log E Kp ∼ (29–33.5) erg. Using the maximum-likelihood method of line fitting, we find that the flare frequency distribution (FFD) for each star in our sample follows a power law with slope ‑α in the range ‑(1.3–2.0). We find that cooler objects tend to have shallower slopes. For some of our targets, the FFD follows either a broken power law, or a power law with an exponential cutoff. For the L0 dwarf 2MASS J12321827-0951502, we find a very shallow slope (‑α = ‑1.3) in the Kepler energy range (0.82–130) × 1030 erg: this L0 dwarf has flare rates which are comparable to those of high-energy flares in stars of earlier spectral types. In addition, we report photometry of two superflares: one on the L0 dwarf 2MASS J12321827-0951502 and another on the M7 dwarf 2MASS J08352366+1029318. In the case of 2MASS J12321827-0951502, we report a flare brightening by a factor of ∼144 relative to the quiescent photospheric level. Likewise, for 2MASS J08352366+1029318, we report a flare brightening by a factor of ∼60 relative to the quiescent photospheric level. These two superflares have bolometric (ultraviolet/optical/infrared) energies 3.6 × 1033 erg and 8.9 × 1033 erg respectively, while the full width half maximum timescales are very short, ∼2 min. We find that the M8 star TRAPPIST-1 is more active than the M8.5 dwarf 2M03264453+1919309, but less active than another M8 dwarf (2M12215066-0843197).

Genesis of magnetic fields in isolated white dwarfs

Science.gov (United States)

Briggs, Gordon P.; Ferrario, Lilia; Tout, Christopher A.; Wickramasinghe, Dayal T.

2018-05-01

A dynamo mechanism driven by differential rotation when stars merge has been proposed to explain the presence of strong fields in certain classes of magnetic stars. In the case of the high field magnetic white dwarfs (HFMWDs), the site of the differential rotation has been variously thought to be the common envelope, the hot outer regions of a merged degenerate core or an accretion disc formed by a tidally disrupted companion that is subsequently accreted by a degenerate core. We have shown previously that the observed incidence of magnetism and the mass distribution in HFMWDs are consistent with the hypothesis that they are the result of merging binaries during common envelope evolution. Here we calculate the magnetic field strengths generated by common envelope interactions for synthetic populations using a simple prescription for the generation of fields and find that the observed magnetic field distribution is also consistent with the stellar merging hypothesis. We use the Kolmogorov-Smirnov test to study the correlation between the calculated and the observed field strengths and find that it is consistent for low envelope ejection efficiency. We also suggest that field generation by the plunging of a giant gaseous planet on to a white dwarf may explain why magnetism among cool white dwarfs (including DZ white dwarfs) is higher than among hot white dwarfs. In this picture a super-Jupiter residing in the outer regions of the white dwarf's planetary system is perturbed into a highly eccentric orbit by a close stellar encounter and is later accreted by the white dwarf.

IC 3475: A stripped dwarf galaxy in the Virgo cluster

International Nuclear Information System (INIS)

Vigroux, L.; Thuan, T.X.; Vader, J.P.; Lachieze-Rey, M.

1986-01-01

We have obtained B and R CCD and H I observations of the Virgo dwarf galaxy IC 3475. The galaxy is remarkable for its very large diameter (approx.10 kpc for a Virgo distance modulus of 31) and is comparable in size to the large dwarfs discussed by Sandage and Binggeli. Its light profile is best fitted by an exponential law, characteristic of a dwarf Magellanic irregular galaxy. It possesses a central bar with many knots and inclusions concentrated toward the center of the galaxy. These knots and inclusions have the same color (B-Rapprox.1.5) as the rest of the galaxy and are best explained as intermediate-age (1--7 x 10 9 yr) star clusters such as those found in the Magellanic Clouds. Despite possessing the photometric structure of a dwarf Magellanic irregular galaxy, IC 3475 contains less than 5.3 x 10 6 M/sub sun/ of neutral hydrogen. Its hydrogen mass to blue light ratio is less than 0.01, approx.60 times less than the mean value observed for dwarf Magellanic irregulars. It is most likely that IC 3475, which is located near the core of the Virgo cluster, is a stripped dwarf galaxy. The very large size of the galaxy (its diameter is approx.1.8 times larger than that of ''normal'' dwarfs) appears to rule out evolution of IC 3475 from a normal dwarf irregular or to a normal dwarf elliptical

Comportamento de 16 porta-enxertos para o tangor Murcott na região de Itirapina-SP Behavior of sixteen rootstocks for Murcott in Itirapina, SP, Brazil

Directory of Open Access Journals (Sweden)

José Orlando de Figueiredo

2006-04-01

Full Text Available Foi monitorado o comportamento de 16 porta-enxertos para o tangor Murcott [Citrus reticulata Blanco x C. sinensis (L. Osbeck], do clone nucelar J, em experimento instalado em 1990, na Fazenda Raio de Sol, Itirapina-SP. Os porta-enxertos foram: tangelo 'Orlando' (C. reticulata Blanco x C. paradisi Macf., laranja 'Caipira DAC' [C. sinensis (L. Osbeck], limão 'Cravo'(C. limonia Osbeck, os trifoliatas 'Kryder 8-5'e 'EEL'[Poncirus trifoliata (L. Raf.] e as tangerinas 'Cleópatra' (C. reshni hort. ex. Tanaka, 'Sunki' [C. sunki (Hayata hort. ex. Tanaka], 'Batangas', 'Oneco', 'Swatow', 'Szinkon', 'Satsuma', 'Cravo', 'Dancy', 'Suen Kat' e 'Pook Ling Ming' (C. reticulata Blanco. As produções foram avaliadas de 1996 a 2003 e as maiores médias foram proporcionadas pelas plantas enxertadas nas tangerinas 'Cleópatra', 'Suen Kat', 'Pook Ling Ming' e 'Sunki' (>40 kg planta-1. Dentre os porta-enxetos que induziram as mais baixas produções, estão os dois trifoliatas, a 'Caipira DAC' e a tangerina 'Cravo' (Sixteen rootstocks were compared in a trial started in 1990, for Murcott tangor, nucellar clone "J", in Itirapina, Brazil. The rootstocks tested were Orlando tangelo (Citrus reticulata Blanco x C. paradisi Macf., sweet orange [C. sinensis (L. Osbeck] cv. Caipira DAC, Rangpur lime (C. limonia Osbeck, Poncirus trifoliata (L. Raf. cv. Kryder 8-5, P. trifoliata (L. Raf. cv. EEL and the mandarins Cleopatra (C. reshni hort. ex. Tanaka, Sunki [C. sunki (Hayata hort. ex. Tanaka] and Batangas, Oneco, Swatow, Szinkon, Satsuma, Cravo, Dancy, Suen Kat and Pook Ling Ming (C. reticulata Blanco. Fruit yield was measured per plant, in a period of seven years (1996-2003. The best yielding rootstocks were Cleopatra, Suen Kat, Pook Ling Ming and Sunki mandarins (> 40 kg tree-1. The two Trifoliate, sweet orange cv. Caipira DAC and Cravo mandarin presented the lowest yields (< 25 kg tree-1. No significant variation was observed for fruit quality characteristics of trees on

Age-related mutations associated with clonal hematopoietic expansion and malignancies.

Science.gov (United States)

Xie, Mingchao; Lu, Charles; Wang, Jiayin; McLellan, Michael D; Johnson, Kimberly J; Wendl, Michael C; McMichael, Joshua F; Schmidt, Heather K; Yellapantula, Venkata; Miller, Christopher A; Ozenberger, Bradley A; Welch, John S; Link, Daniel C; Walter, Matthew J; Mardis, Elaine R; Dipersio, John F; Chen, Feng; Wilson, Richard K; Ley, Timothy J; Ding, Li

2014-12-01

Several genetic alterations characteristic of leukemia and lymphoma have been detected in the blood of individuals without apparent hematological malignancies. The Cancer Genome Atlas (TCGA) provides a unique resource for comprehensive discovery of mutations and genes in blood that may contribute to the clonal expansion of hematopoietic stem/progenitor cells. Here, we analyzed blood-derived sequence data from 2,728 individuals from TCGA and discovered 77 blood-specific mutations in cancer-associated genes, the majority being associated with advanced age. Remarkably, 83% of these mutations were from 19 leukemia and/or lymphoma-associated genes, and nine were recurrently mutated (DNMT3A, TET2, JAK2, ASXL1, TP53, GNAS, PPM1D, BCORL1 and SF3B1). We identified 14 additional mutations in a very small fraction of blood cells, possibly representing the earliest stages of clonal expansion in hematopoietic stem cells. Comparison of these findings to mutations in hematological malignancies identified several recurrently mutated genes that may be disease initiators. Our analyses show that the blood cells of more than 2% of individuals (5-6% of people older than 70 years) contain mutations that may represent premalignant events that cause clonal hematopoietic expansion.

Kinematically Decoupled Cores in Dwarf (Elliptical) Galaxies

NARCIS (Netherlands)

Toloba, E.; Peletier, R. F.; Guhathakurta, P.; van de Ven, G.; Boissier, S.; Boselli, A.; Brok, M. d.; Falcón-Barroso, J.; Hensler, G.; Janz, J.; Laurikainen, E.; Lisker, T.; Paudel, S.; Ryś, A.; Salo, H.

An overview is given of what we know about the frequency of kinematically decoupled cores in dwarf elliptical galaxies. New observations show that kinematically decoupled cores happen just as often in dwarf elliptical as in ordinary early-type galaxies. This has important consequences for the

K2 Ultracool Dwarfs Survey. II. The White Light Flare Rate of Young Brown Dwarfs

Science.gov (United States)

Gizis, John E.; Paudel, Rishi R.; Mullan, Dermott; Schmidt, Sarah J.; Burgasser, Adam J.; Williams, Peter K. G.

2017-08-01

We use Kepler K2 Campaign 4 short-cadence (one-minute) photometry to measure white light flares in the young, moving group brown dwarfs 2MASS J03350208+2342356 (2M0335+23) and 2MASS J03552337+1133437 (2M0355+11), and report on long-cadence (thirty-minute) photometry of a superflare in the Pleiades M8 brown dwarf CFHT-PL-17. The rotation period (5.24 hr) and projected rotational velocity (45 km s-1) confirm 2M0335+23 is inflated (R≥slant 0.20 {R}⊙ ) as predicted for a 0.06 {M}⊙ , 24 Myr old brown dwarf βPic moving group member. We detect 22 white light flares on 2M0335+23. The flare frequency distribution follows a power-law distribution with slope -α =-1.8+/- 0.2 over the range 1031 to 1033 erg. This slope is similar to that observed in the Sun and warmer flare stars, and is consistent with lower-energy flares in previous work on M6-M8 very-low-mass stars; taking the two data sets together, the flare frequency distribution for ultracool dwarfs is a power law over 4.3 orders of magnitude. The superflare (2.6× {10}34 erg) on CFHT-PL-17 shows higher-energy flares are possible. We detect no flares down to a limit of 2× {10}30 erg in the nearby L5γ AB Dor moving group brown dwarf 2M0355+11, consistent with the view that fast magnetic reconnection is suppressed in cool atmospheres. We discuss two multi-peaked flares observed in 2M0335+23, and argue that these complex flares can be understood as sympathetic flares, in which fast-mode magnetohydrodynamic waves similar to extreme-ultraviolet waves in the Sun trigger magnetic reconnection in different active regions.

Kinematics and stellar populations of 17 dwarf early-type galaxies

OpenAIRE

Thomas, D.; Bender, R.; Hopp, U.; Maraston, C.; Greggio, L.

2002-01-01

We present kinematics and stellar population properties of 17 dwarf early-type galaxies in the luminosity range -14> M_B> -19. Our sample fills the gap between the intensively studied giant elliptical and Local Group dwarf spheroidal galaxies. The dwarf ellipticals of the present sample have constant velocity dispersion profiles within their effective radii and do not show significant rotation, hence are clearly anisotropic. The dwarf lenticulars, instead, rotate faster and are, at least part...

Search for brown dwarfs in the IRAS data bases

International Nuclear Information System (INIS)

Low, F.J.

1986-01-01

A report is given on the initial searches for brown dwarf stars in the IRAS data bases. The paper was presented to the workshop on 'Astrophysics of brown dwarfs', Virginia, USA, 1985. To date no brown dwarfs have been discovered in the solar neighbourhood. Opportunities for future searches with greater sensitivity and different wavelengths are outlined. (U.K.)