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ABSTRACT Wood is a material used for various purposes since ancient times and is mainly used in civil and rural construction and industry. Due to the predatory exploitation of known trees, it is necessary to characterize new species for use in urban and rural structures as alternatives of species commonly used. This study aimed to determine the physical and mechanical properties of Guarucaia wood (Peltophorum vogelianum Benth.) based on the Brazilian standard ABNT NBR 7190 (1997) and estimate the strength and stiffness as a function of apparent density using the analysis of variance and also estimate stiffness as a function of its strength. The mechanical properties of P. vogelianum were considered compatible for structural use when compared with others used for the same purpose, being classified in the class C50 of dicotyledon species and evidencing the possibility of its use for structural purposes. According to the results of the poor quality in the fit of regression models in the statistical analysis, the strength and stiffness could not be estimated as a function of apparent density nor stiffness properties as a function of their respective strengths.

Snakins are antimicrobial peptides (AMPs) found, so far, exclusively in plants, and known to be important in the defense against a wide range of pathogens. Like other plant AMPs, they contain several positively charged amino acids, and an even number of cysteine residues forming disulfide bridges which are considered important for their usual function. Despite its importance, studies on snakin tertiary structure and mode of action are still scarce. In this study, a new snakin-like gene was isolated from the native plant Peltophorum dubium, and its expression was verified in seedlings and adult leaves. The deduced peptide (PdSN1) shows 84% sequence identity with potato snakin-1 mature peptide, with the 12 cysteines characteristic from this peptide family at the GASA domain. The mature PdSN1 coding sequence was successfully expressed in Escherichia coli. The purified recombinant peptide inhibits the growth of important plant and human pathogens, like the economically relevant potato pathogen Streptomyces scabies and the opportunistic fungi Candida albicans and Aspergillus niger. Finally, homology and ab initio modeling techniques coupled to extensive molecular dynamics simulations were used to gain insight on the 3D structure of PdSN1, which exhibited a helix-turn-helix motif conserved in both native and recombinant peptides. We found this motif to be strongly coded in the sequence of PdSN1, as it is stable under different patterns of disulfide bonds connectivity, and even when the 12 cysteines are considered in their reduced form, explaining the previous experimental evidences. [ABSTRACT FROM AUTHOR]

Thermal time models may describe and compare seed germination, providing information useful to explain species distribution. However, the capacity of such threshold models to describe germination of tropical native species has been less studied. We evaluated seed germination of a legume tree species ( Peltophorum dubium ), typical from South American seasonal forests, as described by two linear thermal time models: probit model and graphic model. Seeds were provided from four different provenances in a latitudinal gradient in Brazil, and their physical dormancy mechanically released before the trials. Graphic model and probit regression were used to determine thermal parameters (cardinal temperatures and thermal time requirement) on sub- and supra-optimal ranges for the different seed provenances. Germination rate mainly followed linear relationship with temperature, and regression lines of different germination fractions converged base temperature in the x-axis. Therefore, probit model assumed a single-value of base temperature in the sub-optimal range and a normal distribution of thermal time. Base temperature tended to be higher in the Northern provenance, Porto Velho, showing slower germination under cooler temperatures. Supra-optimal temperatures have shown similar thermal time requirements and different values for ceiling temperature, according to model predictions. No clear patterns have been found between seed provenances and thermal time requirement. Both probit and graphic models have provided reasonable predictions of germination times (t10 and t50), except under the coolest temperatures. Probit regression always described at least 70% of seed germination. Thermal time assumptions, linear models applicability and their limitations are discussed. [ABSTRACT FROM AUTHOR]

Peltophorum dubium (Spreng.) Taub. is a Brazilian native forest species that is used in programs of environmental restoration, landscaping and civil construction. It is a seed-propagated plant, but the low physiological quality of the seeds associated with biotic and abiotic stresses can reduce the percentages of germination and emergence. Techniques that allow the expression of the physiological potential of the seeds can improve germination and vigor in short-term. One of these techniques is seeds osmoconditioning, especially under stressful conditions. This work aimed to study if the osmopriming increases germination and vigor of P. dubium seeds. The study consisted of three stages: I - choice of the ideal osmotic potential for imbibition; II - germination and vigor of the osmoprimed seeds under different water contents; III - osmopriming of four seed lots with different vigor. PEG 6000 solution with -0.6 MPa is recommended for osmoconditioning of P. dubium seeds aiming to improve germination and vigor. Seeds with water content close to 10% for osmoconditioning influences the vigor positively. Osmoconditioning can improve physiological aspects of P dubium seeds with good physiological quality. It can reduce germination-emergence time span, favoring stands with greater uniformity and lower probability of biotic and abiotic factors influence. [ABSTRACT FROM AUTHOR]

The aim of this study was to modify several existing biological models by including several predictive variables that take into account the effect of climatic factors on tree height growth. Tree height was measured from 2007 to 2014 on 18 trees for each of the following species: Eucalyptus urophylla x Eucalyptus grandis, Parapiptadenia rigida, Peltophorum dubium, Mimosa scabrella and Schizolobium parahybae. Different existing nonlinear models were fitted to the observed data, and the best fitting models were selected. The inclusion of climatic variables into the selected models (mainly minimum temperature and rainfall) improved their predictions of tree height growth with age, and provided more accurate estimates than those obtained by traditional nonlinear models. Simulations were carried out to explore the variation of tree height growth under different minimum temperature and precipitation regimes. The effects of frost and rainfall variation on height growth curves and their consequences for forest management are discussed. [ABSTRACT FROM AUTHOR]

Knowledge concerning natural regeneration strategies is important due to the effect of natural regeneration on the local ecosystem. The aim of this study was to examine the ecophysiological aspects of the Peltophorum dubium aerial seed bank. Fruits were harvested monthly, before and after seed maturation, from selected trees in the municipality of Lavras, MG, Brazil, for determination of moisture content, acquisition of tolerance to desiccation, seed viability, maintenance of dormancy, and mean germination time. Physiological maturity of the species was attained in June, when low moisture content, maximum dry matter, and high germination percentage were observed. We found that there was no change in dormancy, in germination percentage, or in the protein profile of seeds during the period they remained in the aerial seed bank. The P. dubium species creates an aerial seed bank of short serotiny, with fruits remaining attached to the tree for 9 months. [ABSTRACT FROM AUTHOR]

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Peltophorum dubium (Spreng.) Taub is a forest species native to Brazil endowed with promising forestry features for the purposes of afforestation. However, production of seedlings of high quality through micropropagation is limited by the reduced root formation. As a result, the present study aimed to evaluate the effect of alternative substrates to the agar and the culture period in the in vitro formation of roots. It was tested at 30 and 60 days of in vitro culture, culture media composed of combinations of substrates vermiculite (V), Plantmax® (P) or fine sand (FS) to MS nutritive medium containing 10 µM of 3-indole butyric acid (IBA), with agar or not (A). Was obtained a high survival rate of shoots both the 30 (92.3%) and 60 (82.6%) days of culture. Most culture media yielded high survival (91.1 to 100%) but those containing (P) constituted exceptions. Intense calli formation was observed only after 60 days of culture, in the control, which contained MS and (A), and in those other two treatments containing (V). The best result of root formation as much quantitatively (36.78%) as for the quality were obtained on treatment that included (V) and (A), in addition to MS at 60 days of culture. With the use of (V) in the culture medium there is intense calli formation after 60 days of culture but also there is higher root formation and improvement in the quality when this substrate is combined with nutritive medium MS. [ABSTRACT FROM AUTHOR]

Copyright of Revista Ceres is the property of Revista Ceres and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present research had the aim to evaluate the answers of the arboreal species Schizolobium parahyba (Vell.) Blake (guapuruvu), Mimosa scabrella Benth. (bracatinga), Peltophorum dubium (Spr.) Taubert (canafístula), Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) and the hybrid Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto) in consortium with sugar cane (Saccharum spp.) in two agroforestry arrangement systems (strip - 3x3m + 12m and line - 6x1,5m) submitted to climatic extreme frost conditions, in the Northwest of Rio Grande do Sul. The damages (resistance to frost) were appraised according to the system of notes used by HIGA et al. (2000) in which a note from 0 to 10 was attributed according to the intensity of the damage to the plant. For the resistance degrees to frost, it was adapted the methodology used by CARVALHO (1981), which is also in function of the intensity of the damage to the plant. Upon the frost condition studied, it was observed that the results demonstrated that different of agroforest system arrangements damaged the resistance of the guapuruvu specie, being sensitive in the agroforest system strip and moderatelly tolerant in the system line. In both systems, the species angicovermelho, bracatinga e eucalipto showed resistance, while the canafístula demonstrated to be tolerant. [ABSTRACT FROM AUTHOR]

The methanolic extract of the leaves of Peltophorum vogelianum (Caesalpiniaceae) afforded a new phytoconstituent, 2-methoxy-4,5-dihydroxy-1(7,8-dihydroxyethylene)-8-β-D-glucuropyranoside named as peltophorumyl-β-D-glucuropyranoside (5), along with four known phytoconstituents, 1-pentatriacontanol (1), friedelin (2), β-sitosterol (3) and β-sitosterol-β-D-glucopyranoside (4), which have not been isolated previously from this plant. Their structures were established on the basis of chemical and physical evidence (IR, 1H-NMR, 13C-NMR, DEPT, HSQC, HMBC and MS). Moreover, compound 5 showed significant antimicrobial activity. [ABSTRACT FROM AUTHOR]

This research aimed to characterize the physicmechanical properties of the canafístula wood (Peltophorum dubium (Spreng.) Taub.) from 10 years' old trees. There was determined the specific gravity, shrinkage, modulus of elasticity and modulus of rupture in static bending, modulus of elasticity in compression perpendicular to the grain, compression strength parallel to the grain, hardness, shear and impact resistance. Specific gravity and shrinkage determination were conducted according to COPANT 30:1:004 (1971) and 30:1-005 (1971), respectively, and the mechanical tests followed ASTM D 143- 94 (2000) and NF B51-009 (1942). The specific gravity and the ratio of tangential to radial shrinkage observed, ranked the wood as light and moderately stable, respectively, since the average values of mechanical properties classified the wood as weak to average strength. The technological characteristics observed indicate that when the wood is originated from short rotation plantation, it should be used with caution in situation which requires high dimensional stability and mechanical strength, suggesting the need of older trees. [ABSTRACT FROM AUTHOR]

Copyright of EntomoBrasilis is the property of EntomoBrasilis and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: From the methanolic extract of the leaves of Peltophorum dubium Taub (Leguminosae) was isolated after successive chromatographic procedures a new C-glucoside benzoic acid derivative, 3αC-glucopyranosil-4,5-dihydroxy-2-methoxy-benzoic acid. The structure of this compound was determined by 1D and 2D NMR and MS data analysis. The new compound showed moderate antioxidant activity in the assay and the auto-oxidation of β-carotene in a linolenic acid suspension method. [Copyright &y& Elsevier]