Resumo em Inglês:

ABSTRACT Climate and resource availability at the parent tree location are known to explain progeny characteristics; however, few studies have examined the role of resistance or tolerance to pathogens, even though climate is a main driver of pathogen abundance. We hypothesize that climate at the parent tree location has a relatively greater influence on progeny resistance or tolerance to pathogens than other progeny characteristics, such as seed mass or seedling growth. As a study species we used the vulnerable Neotropical tree Kageneckia lanceolata known to be susceptible to damping-off diseases. We collected seeds from 60 trees along the species` entire elevational gradient in central Argentina as a surrogate for climatic gradient and selected an ample array of parent tree sizes and rockiness under the crown as surrogate of tree access to resources. Seedling survival in a common nursery significantly increased with elevation of the parent tree from 40 to 80 % (P < 0.001), with damping-off being the only identified cause of mortality. We also found a non-significant trend suggesting that proportional growth during the cold semester increased with elevation (P = 0.083). Seed mass, germination, and growth of seedlings were not significantly influenced by elevation (P > 0.05). Parent tree size and rockiness were not related to any of the measured progeny characteristics. We conclude that the pathogenic environment around parental plants might have a great influence on progeny resistance or tolerance to pathogens and suggest that incorporating the pathogen dimension into future progeny studies may yield important findings.

Resumo em Inglês:

ABSTRACT The rainfall-forest canopy interaction can impact on the chemical and physical rain-water features and is expected that different forests will have different effects on throughfall rain-water quality parameters. This study aimed (i) to compare chemical and physical rain-water quality variables observed in both gross precipitation and throughfall measured in two different forest stands (Atlantic semideciduous forest remnant - AFR, and a Eucalyptus urograndis plantation - EUP). Each stand was monitored with 8 internal rain-gauges and one external rain-gauge, encompassing the period from March 2015 to March 2016. The results pointed out a seasonal behavior of chemical and physical rain-water variables. Gross precipitation and throughfall presented different behaviors for pH, NH3, NH4+ and Ca hardness for AFR, and NH3, NH4 +, Phosphate, Chloride, Ca hardness, Total Dissolved Solids and Conductivity for EUP. Besides, significant differences between the stands were found in terms of throughfall indicators for some of the rainfall events, remarkably NH3 and NH4 + which were always higher at AFR. Our findings reinforce that trees and forests promote rain water enrichment with nutrients, performing key role on environmental services such as nutrient water and air pollution mitigation.

Resumo em Inglês:

ABSTRACT Regenerated cellulose properties can be altered and manipulated by various methods and procedures. Coagulation steps in cellulose regeneration process is one of the most crucial step in determining the final properties of the regenerated cellulose products. This study was conducted to investigate the effect of different type of coagulant on the properties of regenerated cellulose membranes (RCM). Hence, the coagulation mechanism will be highlighted and postulated. Cellulose from cotton linter was dissolved in NaOH/urea via precooled method to form cellulose solution and coagulated in three types of coagulant which were distilled water, 5 wt% H2SO4 and 5 wt% (NH4)2SO4 which lead to the formation of RCM. The RCM were air dried and characterized for their physical, mechanical and chemical properties by using X-ray diffraction (XRD), tensile and Fourier transform infrared (FTIR). Results showed that RCM coagulated in distilled water has the highest tensile strength and crystallinity index but showed the lowest value for the elongation at break. Meanwhile, the RCM coagulated in 5 wt% (NH4)2SO4 has the lowest tensile strength and crystallinity index but had the highest value of the elongation at break. From these results, the crystallinity of RCM has affected the elongation at break for all sample. RCM with higher crystallinity have lower elongation at break compared to the one with higher crystallinity. The RCM coagulated in 5 wt% H2SO4 has intermediate results for all tensile strength, elongation at break and crystallinity compared to those coagulated in distilled water and 5 wt% (NH4)2SO4.

Resumo em Inglês:

ABSTRACT Plants can stablish symbiosis with arburcular mycorrhiza fungi (AMF), in which the fungus uses carbohydrates synthesized by plant photosynthesis in exchange for soil nutrients. AMF symbiosis may benefit plants by increasing the rates of nutrient uptake, tolerance to abiotic stresses, protection against pathogens and, by promoting resilience of forest species to adverse conditions. Knowledge about the diversity of mycorrhizas may help stablish relationships of species selection, AMF production and inoculation. Therefore, the objective of this review is to compile information to identify existing patterns in AMF diversity in Brazilian forest ecosystems. Compilation was based in 74 articles (in English, Portuguese and Spanish languages) searched in the Web of Knowledge and selected for having the keywords “forest”, “diversity”, “mycorrhizal” and “Brazil”, and that identified AMF species by spore morphology. Compilation resulted in a list of 164 AMF species and indicated that AMF species are not plant host specific but they are selected by environmental conditions where the host grows. Some AMF species were ubiquitous and some were rare in forest ecosystems. Rare AMF species may be an artefact of AMF identification because, in comparison to molecular tools, spore morphology may underestimate AMF diversity. Four AMF species, Acaulospora scrobiculata, Acaulospora foveata, Clareoideglomus etunicatum and Glomus macrocarpum, were ubiquitous to several biomes, existed in different stage of forest succession and seemed to be adapted to different forest managements. Therefore, A. scrobiculata, A. foveata, A. mellea, C. etunicatum and G. macrocarpum could have potential to be used as AMF inoculant in forest species.

Resumo em Inglês:

ABSTRACT The purpose of this study is to determine the varnish layer hardness and varnish adhesion strength of the varnished Crimean juniper (Juniperus excelsa M. Bieb.) wood growing naturally in the Kastamonu region of Turkey. Test samples were varnished with UV-resistant polyurethane alkyd resin high gloss varnish (PAV) and water-based acrylic resin gloss varnish (WBAV). The varnish adhesion strength test was carried out by using universal testing machine. The varnish layer hardness was measured by using König pendulum hardness tester. Additionally, the colour properties were measured by spectrophotometer equipment that used the L*a*b* colour space. The adhesion strength of the polyurethane varnish and the water-based varnish were determined 2.81 MPa and 2.25 MPa respectively. Surface hardness value for water-based varnish and polyurethane varnish were determined 71 and 25 oscillation respectively. Detecting the performance of polyurethane and water-based varnish applications for the Crimean juniper wood will provide guidance in which type of varnish will be better for finishing. As a result, in varnish applications of the wood, it is recommended that water-based acrylic varnish should be applied when surface hardness is required. In addition, polyurethane alkyd varnish should be applied when better surface adhesion strength is desired.

Resumo em Inglês:

ABSTRACT The objective of this study was to evaluate the thermal decomposition profile of 10 wood species from the semi-arid region of Brazil using thermogravimetric analysis (TGA) to investigate their potential as biomass energy sources. First, flash carbonization was carried out in a muffle furnace, in which wood samples were heated to a maximum temperature of 500°C, and the product yields were determined. The chemical analysis of the wood of each species for the determination of extractive, lignin and ash contents was performed. TGA was performed using sawdust samples heated at 10°C.min−1 up to 625°C under a nitrogen atmosphere at a flow rate of 50 mL.min−1. The thermal decomposition profile was used to evaluate which wood species was more thermally stable. Mimosa tenuiflora and Poincianella pyramidalis woods were the most suitable as biomass energy sources for charcoal production because of their thermal stability and satisfactory carbonization yields. The thermal stability of the 10 wood samples was confirmed by the analysis of the carbonization yields.

Resumo em Inglês:

ABSTRACT This study investigated the effects of pilot-hole diameter in medium density fiberboard (MDF) on the characterization of screw-driving torques. The factors investigated were the embedded screw orientation and pilot hole diameter. Based on the curves obtained from screw-driving process, the measurements of the seating torque (SET) and stripping torque (STT) were obtained. The results of statistical analysis indicated that the SET and STT values in MDF were significantly affected by the pilot hole diameter. In the case of driving screws into the side of MDF material, the mean SET ranged from 0.37 to 1.23 N∙m and STT values ranged from 1.18 to 2.68 N∙m whereas for the face specimens, the mean SET ranged from 0.57 to 1.56 N∙m and STT values ranged from 2.89 to 5.41 N∙m.

Resumo em Inglês:

ABSTRACT The plant vigor defined in the laboratory may not indicate the final quality of seedlings produced under nursery conditions, or even their survival in plantations. So, we evaluated the influence of the storage conditions of Torresea acreana seeds on its emergence, as well as, on the morphological quality of produced seedlings. Seeds were collected in October/2011, packed, transported, conditioned in closed glas pots and stored in three environments for a period of 462 days. The treatments consisted of seedlings produced from seeds: 1 - without storage (control), 2 - stored in a dry chamber, 3 - stored in a humid chamber, and 4 - stored in an uncontrolled environment (laboratory). Sowing was performed in 50 cm³ plastic tubes filled with decomposed pine bark and coconut fiber (50/50 v/v) which were packed in a glasshouse. The study analyzed the percentage of emergence, mean seedlings emergence time, stem diameter, total height, ratio between total height and stem diameter, shoot length, mean root length, total dry biomass, root dry biomass, shoot dry biomass, and Dickson quality index. Seed storage proved to be a negative factor for the emergence and vigor of T. acreana seedlings. The vigor of the seeds is a preponderant factor to increase the morphological quality of the seedlings.

Resumo em Inglês:

ABSTRACT Mimosa bimucronata is a pioneer, easily adapted, fast-growing species used in restoration programs. The objectives of this study were to experimentally compare (1) methods for dormancy breaking; (2) suitable temperature and substrate for germination; and (3) suitable light intensity and substrate volume for seedling production of M. bimucronata. In the first two experiments, the variables percentage of germination, speed of germination and germination mean time were analyzed. In dormancy test, seeds were submitted to ten methods divided into three groups: hot water, sulfuric acid, and control. In the second experiment, effects of five different temperatures and four substrates were evaluated. In the third experiment, morphometric and biomass variables of seedlings were evaluated in two substrate volumes and two light intensities. The most effective method for breaking dormancy was hot water at 80 °C for one minute with post-treatment immersion in water at room temperature for 24 hours. This finding contrasted with the recommended method for dormancy breaking in the Brazilian Rules for Seed Analysis. The most suitable substrates and temperatures for germination were germitest paper at alternating temperatures of 25-35 °C and sand at constant temperature of 30 °C. The most adequate volume of substrate for seedling production was 280 cm3 in both shaded and full sunlight conditions.

Resumo em Inglês:

ABSTRACT The vegetative growth of plants depends on the nutritional conditions of the soil, mainly in relation to the N element. This element favours the formation of cytokines and auxins, essential hormones for sprouting and rooting, respectively. The objective of this study was to evaluate the influence of nitrogen fertilization of Ilex paraguariensis mother trees on epicormic sprouts emission and rooting of its cuttings. Five treatments of fertilization were applied on the mother trees: control; 250 g of urea (N); 250 g of NPK (5-20-10); 500 g of NPK, and; 250 g of NPK with 30 g of micronutrients. Two evaluations (at 240 and 480 days) were carried out for: trees with sprouts emission (%), average sprouts number and their average length (cm). Sprouts were collected at both vegetative evaluations after the application of the experiment (August 2016) and sectioned into cuttings. Cuttings variables were evaluated: survival (%); rooting (%), callus formation (%) and average root number. The best response to epicormic sprouts emission was obtained with 250 g of NPK at 480 days for trees with sprouts (>75%), sprouts number (4.4) and sprouts length (9.9), but considerable results were also obtained at 240 days with urea. For cuttings, the best results were also obtained from sprouts obtained at 480 days for most treatments (>80% survival and rooting). Nitrogen fertilization is essential for a successful vegetative rescue and propagation by cuttings of I. paraguariensis, and longer periods may be able to boost these results.

Resumo em Inglês:

ABSTRACT The non-structural carbon reserves in the various organs of trees are associated with their growth and the mechanism of resilience when exposed to environmental stresses, especially the water deficit. The goal of this study was to develop multivariate models to estimate the amount of non-structural carbohydrates (starch, sucrose, reducing sugars, total sugars and total non-structural carbohydrates) based on near infrared (NIR) spectra measured in solid wood and material reduced to powder. Partial least squares regression was used to associate the amount of non-structural carbohydrates (NSC) obtained by conventional laboratory analysis with NIR spectral signatures. The best predictive models were obtained from the wood reduced to powder. Validity for the NSC prediction in an external set of data presented the following statistics: reducing sugars with R²=0.90 and root mean square error (RMSE) of 2.54% dry matter, total sugars (R²=0.88, RMSE=2.76%), total NSC (R²=0.90, RMSE=2.58%), sucrose (R²=0.82, RMSE=0.06%) and starch (R²=0.80, RMSE=1.03%). The ability of models to estimate the NSC concentration in the growth rings and under divergent environmental conditions demonstrates the potential of the NIR tool to study the physiological responses of plants to different environmental stresses.

Resumo em Inglês:

ABSTRACT The loss of structure, diversity and functions in the rainforests makes it necessary to develop active strategies to restore their economic and ecological values. Planting selected species can help to catalyze ecosystem restoration. The capacity of the plants to survive and grow in the rainforests, where the canopy coverage changes stochastically, is associated with the intrinsic requirements of the species and their phenotypic plasticity. We used a mid-succession subtropical tree (Cabralea canjerana) to describe the morphological and physiological changes in plant acclimation to full sun and under a closed canopy, and to evaluate the establishment of this species under different intensity of canopy coverage in the rainforest. Traits related with light and water use were analyzed to identify if plants were suffering light or water stresses. Plants changed several morphological and physiological traits related with water and light use, to acclimate to different coverings. Water deficit stress drove acclimation under full sun while the stress by excess of light was irrelevant. However low light availability limited growth under the closed forest canopy. Consistently, the better growth and physiological performance were observed in the center of the gaps. The capacity of this species to acclimate both to high and low coverage and to survive makes it appropriate for enrichment programs in tropical and subtropical rainforests. The evaluation of morpho-physiological traits, even in a pot experiment, is useful to know the capacity of the species to survive and grow in different environments in the rainforest.

Resumo em Inglês:

ABSTRACT Many wood species have been employed as floorings, however their performance can vary greatly according to the wood properties and the type of application. Mechanical tests can be performed for simulating the wood floorings in service, but there are no standards for sorting the materials according to their quality as flooring. In this study, the tests carried out in commercial wood species to simulate the performance as flooring and propose a standard of classes resistance. Thus, the performance as wood flooring of Bowdichia nitida Benth (Spr.), Dipteryx odorata (aubl.) Willd, Mimosa scabrella Benth and Tabebuia impetiginosa in service were investigated. These commercial woods flooring were submitted to the falling ball, rolling load, floor surface indentation from small area loads and static and dynamic friction tests. The indentations caused were measured by micrometer coupled to a computer. According to the wood flooring performance in the simulation tests three resistance classes were established: high for indentations lower than 0.005 mm in floor surface indentation from small area loads, intermediate for depressions from 0.121 to 0.300 mm in rolling load test, and low for depressions higher than 0.301 in falling ball test. These classes can be used for predicting the performance, as wood flooring, of lesser known species.

Resumo em Inglês:

ABSTRACT Throughout their useful life structures demand monitoring to verify their conditions of use. Thus, the need arises to seek methodologies capable to evaluate displacements and deformations in structural components of buildings. The objective of this research was to evaluate the use of the particle image velocimetry (PIV) technique to analyze test specimen behavior during a static bending test, additionally a displacement map is presented. The PIV technique measures variations of position of a region in an object from consecutive images from a loading session. The tests were performed on wood of Pinus oocarpa and Eucalyptus grandis, plywood panels, laminated veneer lumber (LVL) and oriented strand board (OSB). The results obtained by the PIV technique were compared to values obtained from dial indicators. It was verified that in all the materials tested, the PIV technique presented results similar to those found in the dial indicators. By means of the Student t test, with a significance level of 1%, some regions of analysis the values found by the PIV technique and the dial indicators were statistically similar. For the analyzed regions that did not achieve statistical equality, a correction equation was calculated (R² higher than 0.99). It was concluded that the PIV technique, with properly adjusted setup, presented results similar to those obtained in the conventional tests, proving its accuracy and reliability in displacement measurements, with the advantage of being a non-destructive and contactless structure monitoring technique.