Sugar has only recently been identified as a key player in triggering bud outgrowth, while hormonal control of bud outgrowth is already well established. To get a better understanding of sugar ...control, the present study investigated how sugar availability modulates the hormonal network during bud outgrowth in Rosa hybrida. Other plant models, for which mutants are available, were used when necessary. Buds were grown in vitro to manipulate available sugars. The temporal patterns of the hormonal regulatory network were assessed in parallel with bud outgrowth dynamics. Sucrose determined bud entrance into sustained growth in a concentration-dependent manner. Sustained growth was accompanied by sustained auxin production in buds, and sustained auxin export in a DR5::GUS-expressing pea line. Several events occurred ahead of sucrose-stimulated bud outgrowth. Sucrose upregulated early auxin synthesis genes (RhTAR1, RhYUC1) and the auxin efflux carrier gene RhPIN1, and promoted PIN1 abundance at the plasma membrane in a pPIN1::PIN1-GFP-expressing tomato line. Sucrose downregulated both RwMAX2, involved in the strigolactone- transduction pathway, and RhBRC1, a repressor of branching, at an early stage. The presence of sucrose also increased stem cytokinin content, but sucrose-promoted bud outgrowth was not related to that pathway. In these processes, several non-metabolizable sucrose analogues induced sustained bud outgrowth in R. hybrida, Pisum sativum, and Arabidopsis thaliana, suggesting that sucrose was involved in a signalling pathway. In conclusion, we identified potential hormonal candidates for bud outgrowth control by sugar. They are central to future investigations aimed at disentangling the processes that underlie regulation of bud outgrowth by sugar.
When unions undertake labor organizing campaigns, they often do so from strong moral positions, contrasting workers’ rights to decent pay or better working conditions with the more venal financial ...motives of management. But how does labor confront management when management itself has moral legitimacy? In With God on Our Side, Adam D. Reich tells the story of a five-year campaign to unionize Santa Rosa Memorial Hospital, a Catholic hospital in California. Based on his own work as a volunteer organizer with the Service Employees International Union (SEIU), Reich explores how both union leaders and hospital leaders sought to show they were upholding the Catholic "mission" of the hospital against a market represented by the other. Ultimately, workers and union leaders were able to reinterpret Catholic values in ways that supported their efforts to organize.More generally, Reich argues that unions must weave together economic and cultural power in order to ensure their continued relevancy in the postindustrial world. In addition to advocating for workers’ economic interests, unions must engage with workers’ emotional investments in their work, must contend with the kind of moral authority that Santa Rosa Hospital leaders exerted to dissuade workers from organizing, and must connect labor’s project to broader conceptions of the public good.
The majority of old and long-to-root roses are enough frost resistant to grow on their own roots in moderate and cool climates. The more often used method of rose propagation are single node stem ...cuttings derived from blooming shoots. The longtime of rhizogenesis causes extended influence of stress condition and precocious commissioning of ageing processes, which results a low rooting percentage. It was hypothesized that in the short season of flowering the amount of nutrients in shoots of stock plants changes, thus affecting the process of rhizogenesis, as well as condition of rooted cuttings, which may be estimated by the contents of biologically active components. The shoots of four cultivars were cut in four phenological stage: flower buds closed, flowers opened, just after petal shedding and 7-14 days after petal fall. The rooting percentage were counted after 10 weeks of rooting. The evaluation of plant material were carried out before and after rooting, including: soluble proteins, chlorophyll a and b, carotenoids, polyphenolic acids, reducing and total soluble carbohydrates. The SDS-page were performed before rooting. The rooting percentage were counted. The research revealed variability, characteristic for each examined cultivar, in the content of biologically active compounds, both before and after rooting, in cuttings harvested from stock plants in successive phases of development. Decrease in pigment contents in leaves of rooted cuttings may suggest a progressing senescence, both during propagation and later in a vegetative season. The cuttings of 'Mousseuse Rouge' rooted similarly when harvested in each of the phenological phases (53.8-67.5%). For other cultivars the highest rooting percentage was obtained for cuttings harvested from shoots with closed flower buds ('Hurdals' 47.5%, 'Maiden's Blush' 55.0%, 'Semiplena' 67.5%). In these cultivars a relationship between rooting percentage and changes in the content of pigments, sugars or/and polyphenolic acids in successive phase was shown.
Roses (Rosa hybrida) are the most important ornamental cut-flowers and breeders' main focus is to develop new desirable modern cultivars. Rose breeding programs center on the introduction of new ...flower colors, thornless stems, higher production and good post-harvest performance. The study of the main pollen traits, such as pollen quantity and quality, viability, longevity, morphological homogeneity, germination and tube growth, is important for building suitable breeding programs. Recently, a number of studies have shown that reactive oxygen species, like hydrogen peroxide, and nitric oxide, are involved in a wide range of signaling processes including pollen tube growth and pollen-pistil recognition. Pollen viability after anther dehiscence is crucial for successful crossbreeding. In the present work, pollen grains from 5 hybrid tea rose cultivars were stored at -20 °C up to 12 months. Pollen viability and germination rate was monitored in order to provide useful information about pollen storage length. Additionally, pollen grains were tested for their content in hydrogen peroxide and nitric oxide by using a novel approach where the fluorescence is read in a quantitative RealTime PCR (qRT-PCR) machine. Pollen viability and in vitro pollen germination capacity varied among the rose genotypes, while a progressive decrease was evidenced during 12 months of storage at low temperature. Both hydrogen peroxide and nitric oxide production were found to be genotype-dependent, whilst accumulation of the two molecules was observed during the storage period. A putative detrimental effect of these molecules during pollen conservation is hypothesized.
The quality and flower yield of roses are directly dependent on the balanced application of macro and micronutrients. In the present study, foliar application of macro- and micronutrients was done ...after every 15 days when new emerging leaves had sprouted after pruning. The results reveal that plants treated with foliar application of micronutrients along with NPK showed significant increase in the growth characteristic like plant height, number of flowers plant super(-1), bud diameter, flower diameter, fresh and dry weight of flower, flower quality, flower stalk length compared to the application of NPK alone and untreated plants (control). Application of foliar fertilizer (NPK = 15:32:7 + micro power) and NPK (15:32:7) + chelated mix micronutrients gave the highest values compared to the other treatments in both cultivars. Cardinal responded well to micronutrients as compared to Whisky Mac in case of cultivars. Leaf total chlorophyll contents, vase life and the mineral contents (NPK) of leaves were significantly increased as a result of foliar application of micronutrients compared to the control treatment. It was concluded that application of micronutrients along with NPK could improve flower yield and quality of roses.
Low temperatures affect flower development in rose (Rosa hybrida), increasing petaloid stamen number and reducing normal stamen number. We identified the low-temperature-responsive R2R3-MYB ...transcription factor RhMYB17, which is homologous to Arabidopsis MYB17 by similarity of protein sequences. RhMYB17 was up-regulated at low temperatures, and RhMYB17 transcripts accumulated in floral buds. Transient silencing of RhMYB17 by virus-induced gene silencing decreased petaloid stamen number and increased normal stamen number. According to the ABCDE model of floral organ identity, class A genes APETALA 1 (AP1) and AP2 contribute to sepal and petal formation. Transcription factor binding analysis identified RhMYB17 binding sites in the promoters of rose APETALA 2 (RhAP2) and APETALA 2-LIKE (RhAP2L). Yeast one-hybrid assays, dual-luciferase reporter assays, and electrophoretic mobility shift assays confirmed that RhMYB17 directly binds to the promoters of RhAP2 and RhAP2L, thereby activating their expression. RNA sequencing further demonstrated that RhMYB17 plays a pivotal role in regulating the expression of class A genes, and indirectly influences the expression of the class C gene. This study reveals a novel mechanism for the homeotic transformation of floral organs in response to low temperatures.
Rosa roxburghii Tratt is an important commercial horticultural crop in China that is recognized for its nutritional and medicinal values. In spite of the economic significance, genomic information on ...this rose species is currently unavailable. In the present research, a genome survey of R. roxburghii was carried out using next-generation sequencing (NGS) technologies. Total 30.29 Gb sequence data was obtained by HiSeq 2500 sequencing and an estimated genome size of R. roxburghii was 480.97 Mb, in which the guanine plus cytosine (GC) content was calculated to be 38.63%. All of these reads were technically assembled and a total of 627,554 contigs with a N50 length of 1.484 kb and furthermore 335,902 scaffolds with a total length of 409.36 Mb were obtained. Transposable elements (TE) sequence of 90.84 Mb which comprised 29.20% of the genome, and 167,859 simple sequence repeats (SSRs) were identified from the scaffolds. Among these, the mono-(66.30%), di-(25.67%), and tri-(6.64%) nucleotide repeats contributed to nearly 99% of the SSRs, and sequence motifs AG/CT (28.81%) and GAA/TTC (14.76%) were the most abundant among the dinucleotide and trinucleotide repeat motifs, respectively. Genome analysis predicted a total of 22,721 genes which have an average length of 2311.52 bp, an average exon length of 228.15 bp, and average intron length of 401.18 bp. Eleven genes putatively involved in ascorbate metabolism were identified and its expression in R. roxburghii leaves was validated by quantitative real-time PCR (qRT-PCR). This is the first report of genome-wide characterization of this rose species.
In this study, a protocol for in vitro propagation of Rosa hybrida L. cv. Al-Taif Rose was established using nodal segments harboring axillary buds as explants. In vitro stages of shoot initiation, ...multiplication and elongation were performed. Explants were cultured on solid Murashige and Skoog medium (MS) supplemented with different concentrations of benzyl aminopurine (BAP, 1, 2 and 3 mg/l) in combination with 1 mg/l kinetin (Kn). Effect of different concentrations and combinations of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on root formation of shoots were studied. The highest percentage of shoot initiation (85%) was observed on MS medium containing 2 mg/l BAP + 1 mg/l Kn, whereas maximum average number of multiplied shoots (2.7) was produced on MS medium with 3 mg/l BAP + 1 mg/l Kn. Highest average number of elongated shoots (26.7) was noticed on MS medium containing 1 mg/l BAP and 1 mg/l Kn. For rooting, highest percentage (66.7%) of rooted shoots was obtained on MS medium supplemented with 2 mg/l IBA. Plantlets with 4 to 5 roots of 3 to 5 cm length were successfully transferred to pots containing sterile peat moss for acclimatization.
Random amplified polymorphic DNA (RAPD) markers have been found to be very useful in studying the genetic variability of different species, including Rosa. Present studies were undertaken for the ...identification and analysis of genetic variation within a collection of 4 species and 30 accessions of rose using RAPD analysis technique. The results showed the molecular distinctions among the genotypes when analysed using 25 RAPD primers. Total amplified bands were 146, out of which 110 were polymorphic, with an average of seven bands per primer. Maximum number of bands (10) was produced by primer GLD-20, while GLC-02 produced the minimum number of bands (2). Maximum polymorphism in the present study was obtained by primer GLA-03, GLA-05, GLA-07, GLA-10, GLC-02, GLC-06, GLC-08, GLC-10, OPG-11 and OPE-19 which produced 100% polymorphic bands, while primer GLB-11 produced only 42.85% polymorphic bands. This study demonstrated the potential of RAPD technique for the characterization of genetic variation within the rose germplasm.
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