73 research outputs found
Cianogênese e estabelecimento do secamento de painel de sangria em seringueira
The objective of this work was to study the influence of cyanogenesis on the onset of irreversible tapping panel dryness (TPD) and the physiological and histological aspects of secondary phloem in the trunk (tapping panel) of rubber trees (Hevea spp.). Two cyanogenic compounds, linamarin and KCN, were applied separately on the trunk bark of healthy mature trees belonging to two Brazilian clones (Fx 4098 and Fx 3899). Changes in histology, latex pressure potential (ΨP) and cyanogenic potential (HCNP) were followed in the trunk inner barks. In addition, the HCNp levels were determined in TPD-affected plants of both clones. The applications of linamarin or KCN in healthy plants decreased latex ΨP, and formed tylosoids associated with in situ coagulation of latex. The clone Fx 4098 had the higher HCNp and showed the quicker and stronger responses to the cyanogenic compounds. Plants with TPD syntoms had a higher HCNp than the untreated healthy ones. Since histological changes are also structural markers of early TPD, it can be inferred that excessive release of cyanide can induce it in sensitive rubber clones.O objetivo deste trabalho foi estudar a influência da cianogênese no estabelecimento do secamento do painel de sangria (TPD) e os aspectos fisiológicos e histológicos do floema secundário do tronco (painel de sangria) em seringueira (Hevea spp.). Dois compostos cianogênicos, linamarina e KCN, foram aplicados separadamente na casca do tronco de árvores sadias de dois clones adultos (Fx 4098 e Fx 3899). Alterações na histologia, potencial de pressão de látex (ΨP) e potencial cianogênico (HCNp) foram monitoradas. Além disso, os níveis HCNp foram determinados em plantas afetadas por TPD, em ambos os clones. A aplicação de linamarina ou KCN em plantas saudáveis causou redução em ΨP e formação de tilosoides associados à coagulação do látex in situ. O clone Fx 4098 apresentou o maior nível de HCNp, e respostas mais intensas e rápidas aos compostos cianogênicos. Plantas com sintomas de TPD têm maior HCNp de que as sadias. Como as alterações histológicas observadas são reconhecidos marcadores estruturais precoces de TPD, pode-se inferir que a liberação excessiva de cianeto pode induzi-las em clones de seringueira sucetíveis
Foreground influence on primordial non-Gaussianity estimates: needlet analysis of WMAP 5-year data
We constrain the amplitude of primordial non-Gaussianity in the CMB data
taking into account the presence of foreground residuals in the maps. We
generalise the needlet bispectrum estimator marginalizing over the amplitudes
of thermal dust, free-free and synchrotron templates. We apply our procedure to
WMAP 5 year data, finding fNL= 38\pm 47 (1 \sigma), while the analysis without
marginalization provides fNL= 35\pm 42. Splitting the marginalization over each
foreground separately, we found that the estimates of fNL are positively cross
correlated of 17%, 12% with the dust and synchrotron respectively, while a
negative cross correlation of about -10% is found for the free-free component.Comment: Submitted to MNRA
The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths
We present the Planck Sky Model (PSM), a parametric model for the generation
of all-sky, few arcminute resolution maps of sky emission at submillimetre to
centimetre wavelengths, in both intensity and polarisation. Several options are
implemented to model the cosmic microwave background, Galactic diffuse emission
(synchrotron, free-free, thermal and spinning dust, CO lines), Galactic H-II
regions, extragalactic radio sources, dusty galaxies, and thermal and kinetic
Sunyaev-Zeldovich signals from clusters of galaxies. Each component is
simulated by means of educated interpolations/extrapolations of data sets
available at the time of the launch of the Planck mission, complemented by
state-of-the-art models of the emission. Distinctive features of the
simulations are: spatially varying spectral properties of synchrotron and dust;
different spectral parameters for each point source; modeling of the clustering
properties of extragalactic sources and of the power spectrum of fluctuations
in the cosmic infrared background. The PSM enables the production of random
realizations of the sky emission, constrained to match observational data
within their uncertainties, and is implemented in a software package that is
regularly updated with incoming information from observations. The model is
expected to serve as a useful tool for optimizing planned microwave and
sub-millimetre surveys and to test data processing and analysis pipelines. It
is, in particular, used for the development and validation of data analysis
pipelines within the planck collaboration. A version of the software that can
be used for simulating the observations for a variety of experiments is made
available on a dedicated website.Comment: 35 pages, 31 figure
Relaxing the Conductivity/Transparency Trade-Off in MOCVD ZnO Thin Films by Hydrogen Plasma
Efeito da cianogênese na incompatibilidade entre clones de copa de seringueira e o clone de painel IPA 1
Genome-wide identification of rubber tree (Hevea brasiliensis Muell. Arg.) aquaporin genes and their response to ethephon stimulation in the laticifer, a rubber-producing tissue
Vegetative development, primary and secondary growth of the shoot system of young Terminalia superba tropical trees, in a natural environment. I. Spatial variation in structure and size of axes
Spatial variations in trunk structure including wood histology and size of axes were examined in 5 21-month-old Terminalia superba Engl and Diels trees, grown in a natural tropical environment. Long and shorter internode series alternated along the main axes, forming rather poorly delimited units of extension. In trunk wood, the paratracheal axial parenchyma of the confluent type formed irregular bands, the spacing of which varied gradually, increasing and decreasing alternately. These widely- and narrowly- spaced parenchyma bands differentiated various wood layers. The radial enlargement and wall thickness of fibres also varied in the same manner, as did, but to a lesser extent, the width of parenchymal bands, the radial enlargement of parenchyma cells and vessels, and the wall thickness of vessels. The number of various wood layers in trunk segments that were defined by variations in intemodal length was not related to the order of appearance of the trunk segments in question. These results suggest that trunk wood exhibited alternating dense and not very dense wood layers, but they did not provide visible structural evidence of a well-pronounced growth periodicity in the main shoot of Terminalia superba. The existence of a structural discontinuity in the peripheral wood and the significance of the basipetal differentiation of the outermost adjacent wood layer have been discussed in relation to seasonal changes in climate and phenology. On the other hand, trunk thickness increased markedly from 5 cm above to 5 cm beneath the upper pseudowhorls of branches. The thickness of axes (branches and trunks) was closely related to the number of sympodial units located in a centrifugal and an upper position respectively. Moreover, a pseudo-whorl of branches was generally inserted in the middle part of trunk segments defined by variations in internodal length. These data indicate trunk-branch correlations. It is suggested that some structural variations in trunk wood could be related to branching.Développement végétatif, croissance primaire et secondaire du système caulinaire de jeunes arbres tropicaux de l'espèce Terminalia superba, dans un environnement naturel. I. Variation dans l'espace de la structure et de la dimension des axes. Les variations dans l'espace de la structure du tronc - y compris l'histologie du bois - et de la dimension des axes furent examinées chez 5 plants de Terminalia superba Engl et Diels âgés de 21 mois et poussant dans un environnement naturel tropical. Des séries d'entre-nœuds longs et plus courts alternaient le long des axes principaux formant des unités de croissance mal délimitées. Dans le bois des troncs, le parenchyme axial paratrachéal, de type confluent, formait des bandes irrégulières dont l'espacement variait graduellement, augmentant et diminuant en alternance. Ces bandes de parenchyme largement et faiblement espacées différenciaient des couches de bois. La dilatation radiale et l'épaisseur des parois des fibres variaient aussi de la même manière que précédemment. Il en était de même, quoique à un moindre degré, de l'épaisseur des bandes de parenchyme, de la dilatation radiale des cellules parenchymateuses et des vaisseaux, et de l'épaisseur des parois des vaisseaux. Le nombre de couches de bois dans les segments de tronc définis par des variations dans la longueur des entre-nœuds n'était pas lié à l'ordre d'apparition des segments en question. Tous ces résultats suggèrent que le bois des troncs présentait des couches alternativement denses et peu denses, mais ils ne donnent pas de preuve structurale d'une périodicité de croissance bien marquée dans la flèche des Terminalia superba. L'existence d'une discontinuité structurale dans le bois périphérique et la signification de la couche de bois adjacente la plus externe sont discutées en relation avec les changements de saison et de phénologie. Par ailleurs, l'épaisseur des troncs s'accroissait de façon marquée de 5 cm au-dessus à 5 cm en-dessous des étages supérieurs de branches. L'épaisseur des axes (branches et troncs) était étroitement liée au nombre d'unités sympodiales en position respectivement centrifuge et supérieure. De plus, un étage de branches était généralement inséré dans la partie médiane des segments de tronc définis par des variations dans la longueur des entre-nœuds. Ces données attirent l'attention sur les corrélations entre branches et tronc. II est suggéré que des variations structurales dans le bois du tronc pourraient être liées à la ramification
Vegetative development, primary and secondary growth of the shoot system of young Terminalia superba tropical trees, in a natural environment. II. Terminal growth, lateral growth and main stem-branch growth correlations
Primary and secondary growths of main and lateral axes of 1-year-old Terminalia superba Engl and Diels trees, as well as some other aspects of vegetative development, were studied in a natural tropical environment and followed for a period of 6 months. During the long rainy season, primary growth of main axes was continuous, but the rates of shoot elongation and leaf emergence fluctuated rhythmically and correlatively. Shoot elongation rhythm often lagged a little behind leaf emergence rhythm. In addition, leaf development was homoblastic. Lateral shoots appeared when leaf emergence was at a maximum; consequently, they were arranged in successive tiers (pseudowhorls of branches). The apposition of sympodial units in the developing tier of the trees- resulting in the typical Terminalia branching - did not depend on the existence of the main apex, but it was limited as soon as new lateral axes branched above the tier in question. From that time, the activity of branch apices and the radial growth of branch bases ceased, or at least were not detected further. Radial growth of trunks was continuous, but the growth rate of the upper parts changed in relation to the occurrence of tiers. Reiteration of the main apex in an accidentally decapitated plant was late: it occurred after the uppermost branch tier had reached a large size. These results indicate different types of growth correlation in the shoot system of young Terminalia superba trees. It is suggested that the particular growth features of this species are related to the presumably successive sink/source roles of the uppermost tier of branches for metabolites. This growth-habit was observed under favourable environmental conditions. At the end of the long dry season, it was not so obvious, since shoot growth could cease for a couple of weeks and radial growth slowed down slightly.Développement végétatif, croissance primaire et secondaire du système caulinaire de jeunes arbres tropicaux de l'espèce Terminalia superba, dans un environnement naturel. II. Croissance terminale, croissance latérale et corrélations de croissance tige principale-branche. Les croissances primaire et secondaire des axes principaux et latéraux de Terminalia superba Engl et Diels âgés de 1 an, ainsi que quelques aspects du développement végétatif, furent étudiés dans un environnement naturel tropical et suivis sur une période de 6 mois. Durant la grande saison des pluies, la croissance primaire des tiges principales était continue, mais les taux d'allongement apical et d'émergence foliaire fluctuaient rythmiquement et corrélativement. Le rythme d'allongement apical était un peu en retard sur le rythme d'émergence foliaire. En plus, le développement des feuilles était homoblastique. Les rameaux latéraux apparaissaient quand l'émergence des feuilles était maximale; en conséquence, ils étaient disposés en étages successifs (pseudo-verticilles de branches). L'apposition d'unités sympodiales dans l'étage en croissance des arbres- aboutissant à la ramification du type Terminalia - ne dépendait pas de l'existence de l'apex principal, mais elle était limitée dès que de nouveaux axes latéraux se ramifiaient au-dessus de l'étage de branches en question. Dès ce moment là, l'activité des apex de branche et la croissance radiale des bases de branche étaient arrêtées, ou du moins non détectées. La croissance radiale des troncs était continue, mais le taux de croissance des parties supérieures changeait en fonction de l'apparition des étages. La réitération de l'apex principal chez une plante accidentellement décapitée était tardive, elle survenait après que l'étage de branches le plus haut ait atteint une grande taille. Ces résultats attirent l'attention sur des types différents de corrélation de croissance dans le système caulinaire des jeunes arbres de l'espèce Terminalia superba. Il est suggéré que les caractéristiques particulières de la croissance de cette espèce sont liées aux rôles vraisemblablement successifs de zone d'appel/ source, de l'étage supérieur de branches à l'égard des métabolites. Ce mode de croissance a été mis en évidence dans des conditions d'environnement favorable. À la fin de la grande saison sèche, il n'a pas pu être observé de façon aussi manifeste, puisque la croissance caulinaire pouvait être arrêtée pendant 1 ou 2 semaines et que la croissance radiale ralentissait légèrement
Micro-Encapsulation and Antifouling Coatings: Development of Poly(lactic acid) Microspheres Containing Bioactive Molecules
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