369 research outputs found
Erinea in the 'Ansonica' grapevine cultivar: trichome complement, histological effects and analysis of chlorophyll fluorescence in affected leaves
Grapevine leaves are usually characterized by trichomes, specialized epidermal cells. They are interesting in ampelography and also important for the plant ecological responses in biotic and abiotic interactions. In nature, the trichome development is a genetic trait but it can be modified by pests as eriophyid mites. Colomerus vitis is quite common and its economic value is sometime substantial. Here, we studied the leaf erineum induced by C. vitis on 'Ansonica' ('Inzolia'), an important grapevine cultivar characterized by a low level of leaf trichome coating. To date, the interaction between C. vitis and grape has been investigated in few pedo-climatic conditions and no data are reported in 'Ansonica'. Therefore, our objectives were: (1) the analysis, in a Tuscan environment, of the morphology and histology of trichomes in 'Ansonica' leaves unaffected or affected by C. vitis; (2) evaluation, in mature leaves, of the effects of the mite both on pigment content and chlorophyll a fluorescence parameters. 'Ansonica' was devoid of glandular trichomes but it has been established the presence of few simple trichomes strictly associated with the veins. In the erineal sectors, a dense proliferation of simple trichomes in the abaxial epidermis and the development of hyperplasia in the adaxial surface were observed. Moreover, the leaf sections in the erineal regions were thicker due to an abnormal development of the lacunar parenchyma, and trichome proliferation was also extended to interveinal regions. Leaves with erinea showed a deficient content of carotenoids, in comparison to unaffected leaves. In 'Ansonica' leaves, C. vitis induced a decrease in the steady-state operational efficiency of photosystem II associated to a reduction in photochemical quenching and an increase in non-photochemical quenching values. In leaves with erinea, the reduction of photosystem II efficiency was extended to foliar areas not directly affected by galls. The collected results highlight that 'Ansonica' is susceptible to attacks by C. vitis and in the case of widespread leaf attacks the productive damage should not be underestimated
Ligulate inflorescence of Helianthus x multiflorus, cv. Soleild’Or, correlates with a mis-regulation of a CYCLOIDEA gene characterised by insertion of a transposable element
Members of CYCLOIDEA (CYC)/TEOSINTE BRANCHED1 (TB1) transcription factor family are essential to control flower symmetry and inflorescence architecture. In the Helianthus annuus genome, ten CYC/TB1 genes have been identified. Studies performed on mutants recognised HaCYC2c as one of the key players controlling zygomorphism in sunflower.
We identified CYC2c genes in the diploid Helianthus decapetalus (HdCYC2c) and in the interspecific hybrid Helianthus × multiflorus (H × mCYC2cA and H × mCYC2cB), a triploid (2n = 3× = 51), originated from unreduced eggs of H. decapetalus fertilised by reduced H. annuus male gametes. Phylogenetic analysis showed that HdCYC2c and H × mCYC2c were placed within a CYC2 subclade together with HaCYC2c but distinct from it. The present data showed that in H. × multiflorus the allele derived from H. annuus is deleted or highly modified.\ud
The H. × multiflorus taxon exists as radiate and ligulate inflorescence types. We analysed CYC2c expression in H. decapetalus and in the cultivar ‘Soleil d'Or’ of H. × multiflorus, a ligulate inflorescence type with actinomorphic corolla of disk flowers transformed into a zygomorphic ray‐like corolla.
In H. decapetalus, the HdCYC2c gene showed differential expression between developing flower types, being up‐regulated in the corolla of ray flowers in comparison to the disk flower corolla. In H. × multiflorus, an insertion of 865 bp, which is part of a CACTA transposable element, was found in the 5′‐untranslated region (5′‐UTR) of H × mCYC2cB. This insertion could promote, even with epigenetic mechanisms, ectopic expression of the gene throughout the inflorescence, resulting in the observed loss of actinomorphy and originating a ligulate head
Molecular analysis of a sunflower gene encoding an homologous of the B subunit of a CAAT binding factor
A genomic DNA fragment containing the
complete LEAFY COTYLEDON1-LIKE (HaL1L) gene was
retrieved by chromosome walking. Its sequence was confirmed
and elongated by screening a sunflower genomic
DNA BAC Library. HaL1L, whose cDNA had already
been sequenced and characterized, encodes a NF-YB subunit
of a CCAAT box-binding factor (NF-Y) involved in
the early stages of zygotic and somatic embryogenesis in
the Helianthus genus. In the HaL1L 50-flanking region,
elements specific to a putative TATA-box promoter and
two ‘‘CG isles’’ were identified. An investigation of the
methylation status of these CG rich DNA regions showed
that differentially methylated cytosines were recognizable
in the DNA of embryos on the fifth day after pollination in
comparison to leaf DNA suggesting that during plant
development epigenetic regulation of HaL1L transcription
was achieved by methylating cytosine residues. We also
searched the HaL1L nucleotide sequence for cis-regulatory
elements able to interact with other transcription factors
(TFs) involved in the HaL1L regulation. Of the elements
identified, one of the most intriguing is WUSATA, the
target sequence for the WUSCHEL (WUS) TF, which may
be part of a complex regulation network controlling
embryo development. In this article, we show that the
WUSATA target site, located in the intron of HaL1L, is
able to bind the TF WUS. Interestingly, we found auxin
and abscisic acid responsive motifs in the HaL1L promoter
region suggesting that this gene may additionally by under
hormonal control. Finally, the presence of a cytoplasmic
polyadenylation signal downstream to the coding region
indicates that this gene may also be controlled at the
translation level by a temporarily making the pre-synthesized
HaL1L mRNA unavailable for protein synthesis
Vibrations of the S1 state of fluorobenzene-h5 and fluorobenzene-d5 via resonance-enhanced multiphoton ionization (REMPI) spectroscopy
We report resonance-enhanced multiphoton ionization spectra of the isotopologues fluorobenzeneh5 and fluorobenzene-d5. By making use of quantum chemical calculations, the changes in the wavenumber of the vibrational modes upon deuteration are examined. Additionally, the mixing of vibrational modes both between isotopologues and also between the two electronic states is discussed. The isotopic shifts lead to dramatic changes in the appearance of the spectrum as vibrations shift in and out of Fermi resonance. Assignments of the majority of the fluorobenzene-d5 observed bands are provided, aided by previous results on fluorobenzene-h5
Rentabilidade econômica da produção de uva em louveira (sp) em diferentes sistemas de produção.
O presente trabalho foi desenvolvido junto aos produtores de uva do município de Louveira (SP) objetivando realizar uma análise de custo/benefício de três sistemas de produção aqui referidos por sistema tradicional, sistema alternativo 1 e sistema alternativo 2. Louveira é uma região com relevo ondulado e montanhoso com declives acentuados, e afloramentos rochosos. A fertilidade do solo varia de média a baixa e na maior parte do município os solos são muito susceptíveis à erosão. Embora a uva seja uma cultura que se adapta bem às condições edafoclimáticas de Louveira, para que o seu cultivo seja sustentável, dada as características citadas acima, o manejo da cultura deve utilizar técnicas que preservem a estrutura do recurso solo. No município ocorrem cerca de 3.500.000 pés de uva, distribuídos entre 397 produtores, 98% dos quais constituem agricultores familiares. Os produtores podem ser diferenciados quanto à tecnologia, uso de capital e práticas de cobertura no solo, no entanto, utilizam a mesma técnica de preparo do solo, tanto na implantação quanto na renovação da cultura, que ocorre a cada quinze anos. Foram analisadas três propriedades em áreas de LATOSSOLOS VERMELHO-AMARELOS argilosos, pouco profundos, bem drenados e de baixa fertilidade, derivados de filitos, gnaisses, xistos e granitos (Comissão de Solos, 1960; Oliveira et al., 1999). Os custos e benefícios foram avaliados sob a ótica da rentabilidade privada de uma atividade econômica, o que permite evidenciar a rentabilidade dos processos produtivos do ponto de vista privado ou do agricultor (NORONHA,1997). Os dados sobre custo, produtividade e preço foram levantados junto à Casa da Agricultura de Louveira para a produção de uva Niagara Rosada, no sistema latada. Esses parâmetros são concordantes com os publicados pela EMBRAPA (Maia e Mello, 2003). O Quadro 1 evidencia as diferenças de custo de produção, produtividade e preço da uva Niagara Rosada para os três sistemas de produção
Augmentation of abscisic acid (ABA) levels by drought does not induce short-term stomatal sensitivity to CO2 in two divergent conifer species
The stomata of conifers display very little short-term response to changes in atmospheric CO2 concentration (Ca), whereas the stomatal responses of angiosperms to Ca increase in response to water stress. This behaviour of angiosperm stomata appears to be dependent on foliar levels of abscisic acid (ABAf). Here two alternative explanations for the stomatal insensitivity of conifers to Ca are tested: that conifers have either low ABAf or a higher or absent threshold for ABA-induced sensitivity. The responsiveness of stomatal conductance (gs) to a sequence of transitions in Ca (386, 100, and 600 μmol mol−1) was recorded over a range of ABAf in an angiosperm and two divergent conifer species. The different ABA levels were induced by a mild drought cycle. Although the angiosperm and conifer species showed similar proportional increases in ABAf following drought, conifer stomata remained insensitive to changes in Ca whereas angiosperm stomata showed enhanced sensitivity with increasing ABAf. The conifers, however, had much higher ABAf prior to drought than the angiosperm species, suggesting that non-sensitivity to Ca in these conifers was due to an absent or inactive response/signalling pathway rather than insufficient ABAf
Review: Current status of corpus luteum assessment by doppler ultrasonography to diagnose non-pregnancy and select embryo recipients in cattle.
A number of potentials uses of Doppler ultrasonography have been explored in the last decades, both as research tools in reproductive physiology investigations and for the reproductive management of farm animals. The objective of this review was to address some of the recent strategies developed in fixedtime reproductive programs and resynchronization of ovulation in cattle, based on the evaluation of corpus luteum function by color-Doppler ultrasound imaging. Recent studies in dairy and beef cattle pointed out to a high accuracy when Doppler ultrasonography is used to assess the functionality of the corpus luteum and identify non-pregnant females at 20?24 days after breeding. Therefore, super-early resynchronization programs starting in the second week after timed-artificial insemination or embryo transfer have been developed and are being implemented in commercial assisted reproduction programs; thus, anticipating conception with proven semen or genetically superior embryos. In addition, assessment of corpus luteum blood perfusion can be used for identifying high fertility embryo recipients in fixedtime embryo transfer programs
Consistent assignment of the vibrations of symmetric and asymmetric para-disubstituted benzene molecules
We give a description of the phenyl-ring-localized vibrational modes of the ground states of the para-disubstituted benzene molecules including both symmetric and asymmetric cases. In line with others, we quickly conclude that the use of Wilson mode labels is misleading and ambiguous; we conclude the same regarding the related ones of Varsányi. Instead we label the modes consistently based upon the Mulliken (Herzberg) method for the modes of para-difluorobenzene (pDFB). Since we wish the labelling scheme to cover both symmetrically- and asymmetrically-substituted molecules, we apply the Mulliken labelling under C2v symmetry. By studying the variation of the vibrational wavenumbers with mass of the substituent, we are able to identify the corresponding modes across a wide range of molecules and hence provide consistent assignments. Particularly interesting are pairs of vibrations that evolve from in- and out-of-phase motions in pDFB to more localized modes in asymmetric molecules. We consider the para isomers of the following: the symmetric dihalobenzenes, xylene, hydroquinone, the asymmetric dihalobenzenes, halotoluenes, halophenols and cresol
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