GJMS-like operators on symmetric 2-tensors and their gravitational duals

We study a family of higher-derivative conformal operators $P_{2k}^{(2)}$ acting on transverse-traceless symmetric 2-tensors on generic Einstein spaces. They are a natural generalization of the well-known construction for scalars. We first provide the alternative description in terms of a bulk Poincar\'e-Einstein metric by making use of the AdS/CFT dictionary and argue that their holographic dual generically consists of bulk massive gravitons. At one-loop quantum level, we put forward a holographic formula for the functional determinant of the higher-derivative conformal operators $P_{2k}^{(2)}$ in terms of the functional determinant for massive gravitons with standard and alternate boundary conditions. The analogous construction for vectors $P_{2k}^{(1)}$ is worked out as well and we also rewrite the holographic formula for unconstrained vector and traceless symmetric 2-tensor by decoupling the longitudinal part. Finally, we show that the holographic formula provides the necessary building blocks to address the massless and partially massless bulk gravitons. This is confirmed in four and six dimensions, verifying full agreement with results available in the literature.Comment: 15 Pages, 0 figures. Minor change

Irradiación de rizomas in vitro de Alstroemeria aurea G. con rayos gamma: una aproximación a la dosis apropiada para utilizar en mejoramiento genético

Gamma irradiation has been widely used as a breeding technique to obtain new cultivars in ornamental species such as Alstroemeria, where several cultivars have been obtained through rhizome radiation. The optimum dosage for an appropriate induction of mutation must be considered for breeding purposes and it depends mainly on plant susceptibility. Thus in this study in vitro cultured rhizomes of Alstroemeria aurea were irradiated with a gamma source using different dosages to evaluate the direct effect produced. Damage and number of rhizome sprouting were observed and recorded during 61 days after irradiation. At the end of this period, rhizomes were weighted and mortality was evaluated. Both mortality and weight increased depending on dosage. All irradiated rhizomes showed early sprouting in comparison with control (0 Gy) and no significant difference in final number of shoots after 61 days among irradiated treatments was observed. Bleaching and necrosis was observed in all irradiated rhizomes and was more evident at higher doses. LD50 was established at about 40 Gy and the optimum dosage to induce mutation was suggested between 2.5 and 5 Gy, when the growth was reduced in 50%, and probably this dosage could be used for breeding purposes.Gamma irradiation has been widely used as a breeding technique to obtain new cultivars in ornamental species such as Alstroemeria, where several cultivars have been obtained through rhizome radiation. The optimum dosage for an appropriate induction of mutation must be considered for breeding purposes and it depends mainly on plant susceptibility. Thus in this study in vitro cultured rhizomes of Alstroemeria aurea were irradiated with a gamma source using different dosages to evaluate the direct effect produced. Damage and number of rhizome sprouting were observed and recorded during 61 days after irradiation. At the end of this period, rhizomes were weighted and mortality was evaluated. Both mortality and weight increased depending on dosage. All irradiated rhizomes showed early sprouting in comparison with control (0 Gy) and no significant difference in final number of shoots after 61 days among irradiated treatments was observed. Bleaching and necrosis was observed in all irradiated rhizomes and was more evident at higher doses. LD50 was established at about 40 Gy and the optimum dosage to induce mutation was suggested between 2.5 and 5 Gy, when the growth was reduced in 50%, and probably this dosage could be used for breeding purposes

Chemical and Sensorial Characterization of Scented and Non-Scented Alstroemeria Hybrids

Floral scent plays an important ecological role attracting pollinators. Its composition has been elucidated for a vast diversity of species and is dominated by volatile organic compounds (VOCs) such as monoterpenoids, sesquiterpenoids, phenylpropanoids and benzenoid compounds. Considering that floral scent is also an important character for the ornamental plant market, this study was aimed at characterizing and comparing the molecular composition of scented and non-scented alstroemeria flowers. Confirmation of floral scent was performed through sensorial analysis, while GC-MS analysis detected monoterpenes and esters as major volatile organic compounds (VOCs). A total of 19 and 17 VOCs were detected in the scented hybrids 13M07 and 14E07, respectively. The non-scented hybrid 13B01 shared 14 VOCs with the scented hybrids, although it showed different relative concentrations. Comparison between scented and non-scented hybrids suggests that diversity and amounts of VOCs are likely due to the ecological role of scent, while the human perception of floral scent is not strictly related to the VOC profile.Gobierno de Chile 11130325, EQM13012

Floral scent evaluation of three cut flowers through sensorial and gas chromatography analysis

The main function of floral scent is to attract and guide pollinators, but it is also an important character in the ornamental plant industry. Several studies have considered the chemical evaluation of floral scent during vase life, but only a few have considered sensorial analysis of this character, which is a very important quality trait for the marketing of ornamental plants. This study focused on assessing the floral scent of three fragrant cut flowers of high economic importance: Lilium, chrysanthemum, and freesia. Eighty individuals were included in a sensorial analysis where the attributes of floral scent liking and intensity were evaluated. The composition of the floral scent was analyzed through the collection of headspace followed by gas chromatography-mass spectrometry (GC-MS). The floral scents of oriental lily and freesia were perceived as more intense, compared to chrysanthemum. A total of 28 volatile compounds were detected and the monoterpenes β-pinene (40.7 ± 1.8 μg·L−1), β-cis-ocimene (5552 ± 990 μg·L−1), and linalool (11,800 ± 220 μg·L−1) were the major volatile organic compounds (VOCs) present in chrysanthemum, lilium, and freesia, respectively. The results presented in this study confirm that the concentration and abundance of volatile compounds is not directly related to the human perception of floral scen

Floral scent evaluation of segregating lines of Alstroemeria caryophyllaea

Floral scent plays an important role in attracting and guiding pollinators and is composed of a bouquet of volatile organic compounds (VOCs). Alstroemeria is a commercially important cut flower, however breeding efforts have focussed on flower colour and size rather than scent. Recently analysis of two scented cultivars derived from the scented Alstroemeria caryophyllaea revealed a surprising divergence in VOC profiles. Here 13 scented lines of A. caryophyllaea derived from selfing were characterized including morphology, evaluation of the floral scent through GC–MS and sensorial analysis. Leaf shape, stem length, flower size, shape, colouration and productivity all varied between lines. Sensorial analyses indicated that two lines (C013 and C017) were most highly rated for their appearance and C017 was also scored highest for its scent contrasting with C004 which scored lowest. Analyses of scent bouquets from six of the lines revealed 23 terpenoid compounds. All lines showed the same most abundant compound putatively identified as β-trans-ocimene, and three further compounds were discriminatory amongst the lines following PCA. Genomic organization of AlstroTPS, a previously identified myrcene synthase, showed substantial polymorphism between lines. The multifactorial characterization performed in this study showed differences among the lines confirming parental heterozygosity

Volatile emissions of scented Alstroemeria genotypes are dominated by terpenes, and a myrcene synthase gene is highly expressed in scented Alstroemeria flowers

Native to South America, Alstroemeria flowers are known for their colourful tepals, and Alstroemeria hybrids are an important cut flower. However, in common with many commercial cut flowers, virtually all the commercial Alstroemeria hybrids are not scented. The cultivar ‘Sweet Laura’ is one of very few scented commercial Alstroemeria hybrids. Characterization of the volatile emission profile of these cut flowers revealed three major terpene compounds: (E)-caryophyllene, humulene (also known as α-caryophyllene), an ocimene-like compound, and several minor peaks, one of which was identified as myrcene. The profile is completely different from that of the parental scented species A. caryophyllaea. Volatile emission peaked at anthesis in both scented genotypes, coincident in cv. ‘Sweet Laura’ with the maximal expression of a putative terpene synthase gene AlstroTPS. This gene was preferentially expressed in floral tissues of both cv. ‘Sweet Laura’ and A. caryophyllaea. Characterization of the AlstroTPS gene structure from cv. ‘Sweet Laura’ placed it as a member of the class III terpene synthases, and the predicted 567 amino acid sequence placed it into the subfamily TPS-b. The conserved sequences R28(R)X8W and D321DXXD are the putative Mg2+-binding sites, and in vitro assay of AlstroTPS expressed in Escherichia coli revealed that the encoded enzyme possesses myrcene synthase activity, consistent with a role for AlstroTPS in scent production in Alstroemeria cv. ‘Sweet Laura’ flowers

Induction of direct organogenesis from aerial explants of scented alstroemeria genotypes

Alstroemeria is an important pot plant and cut flower in the ornamental plant market, and its propagation mainly occurs by rhizome division. However, this method is inefficient and time-consuming and may contribute to the spread of viruses. This study focused on developing in vitro propagation protocols using aerial explants of Alstroemeria caryophyllaea and A. ‘Sweet Laura’, two scented genotypes. Aerial explants of alstroemeria were regenerated by testing three types of aerial explants and four concentrations of cytokinins. Both A. caryophyllaea and A. ‘Sweet Laura’ showed the highest induction rate from shoots, with values of 35 and 63.3%, respectively. For both genotypes, the optimum BAP concentration for direct organogenesis from buds was 1.0 mg L-1. Finally, a successful protocol for in vitro propagation of A. caryophyllaea and A. ‘Sweet Laura’ through direct organogenesis from aerial explants was generated.Alstroemeria es una especie importante en el mercado de plantas ornamentales y flores de corte y su propagación es principalmente realizada por división de rizomas. Sin embargo, este método es ineficiente, altamente demandante de tiempo y puede contribuir a la dispersión de virus. Este estudio tuvo como objetivo desarrollar un protocolo de propagación in vitro usando explantes aéreos de Alstroemeria caryophyllaea y A. cv. ‘Sweet Laura’, dos genotipos aromáticos. Los explantes aéreos de alstroemeria fueron regenerados probando tres tipos de explantes y cuatro concentraciones de citoquininas. Tanto A. caryophyllaea como A. cv. ‘Sweet Laura’ mostraron la mayor tasa de inducción desde brotes, con valores de 35 y 63,3%, respectivamente. Para ambos genotipos la concentración óptima de BAP para desarrollar organogénesis directa desde brotes fue de 1.0 mg L-1. Finalmente, se generó un protocolo exitoso para la propagación in vitro de A. caryophyllaea y A. cv. ‘Sweet Laura’ a partir de explantes aéreos