Potencial da espectroscopia no infravermelho próximo para distinção de carvão de madeira de Eucalyptus e nativa

The objective of this study was to evaluate the potential of near infrared spectroscopy (NIRS) associated with multivariate statistics to distinguish coal produced from wood of planted and native forests. Timber forest species from the C errado (Cedrela sp., Aspidosperma sp., Jacaranda sp. and unknown species) and Eucalyptus clones from forestry companies (Vallourec and Cenibra) were carbonized in the final temperatures of 300, 500 and 700°C. In each heat treatment were carbonized 15 specimens of each vegetal material totaling 270 samples (3 treatments x 15 reps x 6 materials) produced in 18 carbonization (3 treatments x 6 materials). The acquisition of the spectra of coals in the near infrared using a spectrometer was performed. Principal Component Analysis (PCA) and Partial Least Squares Regression (PLS-R) were carried out in the spectra. NIR Spectroscopy associated with PCA was not able to differentiate charcoals produced from native and planted woods when utilizing all carbonized samples at different temperatures in the same analysis; The PCA of all charcoals was able to distinguish the samples depending on temperature in which they were carbonized. However, the separation of native and planted charcoal was possible when the samples were analyzed separately by final temperature. The prediction of native or planted classes by PLS-R presented better performance for samples carbonized at 300°C followed by those at 500°C, 700°C and for all together.

A sucessão ecológica em ambientes florestais em restauração: estrutura e dinâmica da regeneração natural

Ecological restoration aims to restore the self-sustainability potential of degraded environments. The successional trajectory of areas in restoration may differ from the reference ecosystem on a number of factors, especially the disturbance history of the area and management techniques applied in order to reverse the degradation scenario. In this sense, the objective of this study was to characterize the dynamics of natural regeneration and the structure of the regenerating community in an area of ecological restoration for 25 years on the right bank of the Rio Grande in the Power Station in Camargos that belongs to the Companhia Energetica de Minas Gerais - CEMIG, Nazareno, MG, in order to identify the current state of environmental regeneration. In November 2014, there was the first community inventory of seedlings existing in regeneration subplots (2 x 2 m) within the inclusion criteria (height ≥ 10 cm and DBH <5 cm), divided into 44 subplots (11 plots) in two areas, one area in restoration (REF) and a fragment of native vegetation (FRAG). In October 2015, the second sampling was carried out, in which individuals were resampled and recruits and dead individuals quantified. The parameters abundance, floristic similarity, density, dominance, importance value, equability, richness and diversity were analyzed in both samples. The dynamics was evaluated for the number of individuals and basal area in the period of 2014-2015 and individuals distributed according to height. The history of usage area provoked different behavior between the study environments; the patterns of the FRAG and REF communities along the years allowed the distinction between environments and demonstrated great environmental diversity, with differences in the abundance of species, floristic similarity, richness, diversity, vertical structure and dynamics parameters. In the REF area, there was a considerable increase in the density of individuals along the years and the establishment of different species. In this sense, the evaluation of natural regeneration in REF has shown that resilience is gradually being resumed, a necessary condition to support the potential for environmental self-sustainability. However, given the disturbance history, it can be concluded that the environment moves to an alternative state, which is possibly different from that prior to degradation.

Metodologias para a avaliação do potencial fisiológico de sementes de tabaco

Despite tobacco being a culture propagated by seeds, there is little information concerning tests that allow the distinction of similar germination lots in different levels of vigor. The diversity of cultivars available in the market, and a few peculiarities of the species, such as uneven maturation of the flowers, fruits and seeds, small size and seed dormancy, are considered obstacles for obtaining lots of tobacco of high physiological potential. Thus, this research was developed with the objective of adapting feasibility and vigor tests for evaluating the physiological potential of tobacco seed lots. We used nine lots of tobacco seeds of cultivar CSC 447 and nine lots of seeds of cultivar BAT 2101, belonging to variety groups Virginia and Burley, respectively. Initially, germination test was conducted to characterize the profile of the lots. For determining the feasibility and vigor of the tobacco seeds, germination tests were conducted in distinct temperatures, controlled emergence conditions, electric conductivity, artificial aging and in tetrazolium. For determining the isoenzymatic marker for seed quality, analyses were conducted with enzymes catalase, esterase, malate dehydrogenase and alcohol dehydrogenase. In conclusion, the emergence tests at 25oC and artificial aging at 41oC for 72 hours, are efficient in discriminating the lots of tobacco seeds in different levels of vigor. The electric conductivity and germination tests in different temperatures have distinct responses in relation to the genotype of the tobacco seeds. The tetrazolium test using the methodology with pre-conditioning in 3.5% sodium hypochlorite solution and subsequent emersion in 1.0% tetrazolium solution for 18 hours is efficient for the quick evaluation of the feasibility of tobacco seeds. The analysis of the profiles of enzymes catalase, esterase, malate dehydrogenase and alcohol dehydrogenase is efficient as markers for tobacco seed quality.