The aim of this work was to assess the geographic distribution of coffee quality in Minas Gerais state, Brazil, and to study its interactions with chemical and environmental factors. Correlations between environmental factors, chemical compounds and sensory quality of participants of the Minas Coffee Quality Contest were made through Principal Component Analysis and Biplot Graphics. The results showed discriminations of high and low scores as a result of environmental variables, demonstrating a strong influence of temperature, rainfall, altitude and latitude on the quality of the coffees studied. In addition to the environmental characteristics, the chemical compounds trigonelline, caffeine, and especially the acid-5-cafeiolquinic were also relevant in discriminating the scores obtained through sensory analysis. This work is an initial indication of the factors that determine the quality of coffees produced in Minas Gerais.

Priming has been used to improve the performance of germination at the field, and potassium nitrate (KNO 3 ) is a promising compound for this purpose. The nitrate (NO 3 ) could be absorbed, being used in the metabolism of the embryo, through the enzyme nitrate reductase (NR). Besides, the priming could also activate the response of the antioxidant system, becoming the primed seeds more prepared for possible stresses. Thus, the aim of this study was to evaluate the metabolic effect of nitrate in tomato seed germination by the quantification of NR activity, and also evaluate the activity of some antioxidant enzymes as superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX). Tomato seeds were primed using solutions of polyethylene glycol (PEG 6000) -1,1MPa, 50 mM KNO 3 and PEG+KNO 3 . The variables analyzed were germination (germinability, mean germination time, mean germination rate, coefficient of variation of the germination time, uncertainty and synchrony) nitrogen, total proteins and enzymes. The germination data were analyzed using an ANOVA, comparing the averages by Scott-Knott test (P < 0.05). To analyze the nitrogen, protein and enzymatic activities, we used a Kruskal-Wallis test (P < 0.05). The results show an increase in the NR activity, as well as in the antioxidant enzymes. The germination time (t) and germination rate (v) primed in KNO 3 had a better performance compared to the other treatments. In conclusion, the observed benefits in tomato seeds primed with KNO 3 were related to the activity of the enzyme nitrate reductase in the production of nitrite/nitric oxide, which acted promoting a faster germination.

Four levels of shading (full sunlight (0%), 30, 50, 70% of solar radiation interception on growth, chlorophyll concentration and photosynthetic rate were studied in Croton urucurana Baill., a pioneer plant species. This species seedlings are of potential interest for reforestation projects and recovery of degraded areas. The seedlings were grown in pots containing soil and sand (2:1) and later transferred to plastic bags of 3 dm³ and submitted to different levels of shading (30, 50, 70%) of solar radiation and full sunlight, as control. The experimental design was completely randomized with five replicates and each experimental unit was composed of five plants. The results suggest that plants submitted to 70% shading showed higher dry weight accumulation in leaf and root, and higher plant height and leaf area. However, the seedlings root system showed higher dry biomass under full sunlight. It was observed a tendency to increase chlorophyll concentration and to decrease photosynthetic rate with the increase of the shading level.

O plantio de essências nativas, seja com finalidade econômica ou conservacionista, requer uma série de cuidados que dependem do conhecimento prévio de suas características fisiológicas e exigências ecológicas nas diversas etapas de seu ciclo vital. O estudo do crescimento e desenvolvimento de uma planta, em diferentes condições ambientais, oferece ao pesquisador bom indício sobre quais as melhores condições para se cultivar determinada espécie. Objetivou-se avaliar o crescimento inicial e as concentrações de clorofilas em plantas jovens de Cryptocaria aschersoniana Mez. (Canela-Batalha), submetidas a níveis de redução da radiação solar: 0% (Pleno Sol), 30%, 50% e 70%. Os resultados demonstram que o teor de clorofila total foi maior nas plantas cultivadas em 70% de sombreamento, o mesmo ocorrendo com a razão clorofila a/b. A maior altura foi apresentada pelas plantas cultivadas em 50% de sombreamento. Do ponto de vista de acúmulo de matéria seca total e matéria seca de raízes, a melhor performance foi observada nas plantas em 30% de sombreamento e o maior acúmulo de matéria seca de folhas verificado nas plantas cultivadas em 30 e 50% de sombreamento. Conclui-se que as melhores condições de cultivo para mudas de Cryptocaria aschersoniana Mez. (Canela-Batalha) foram os níveis de 30 e 50% de redução da radiação solar incidente.

Improved re-establishment of desiccation tolerance was studied in germinated seeds of Tabebuia impetiginosa Mart. by exposing to a polyethylene glycol solution prior to desiccation. The effects of different osmotic potentials and drying rates were studied. In addition, temporary temperature stress and exogenous abscisic acid were applied to evaluate their effect on desiccation tolerance of the protruded radicle. An osmotic potential of -1.7 MPa at 5°C followed by slow drying was most effective in the re-establishment of desiccation tolerance in protruded radicles with a length up to 3 mm. An osmotic potential of -1.4 or -2.0 MPa was less effective. Fast drying completely prevented the re-induction of desiccation tolerance. Cold shock or heat shock prior to osmotic treatment as well as abscisic acid added to the osmotic solution improved desiccation tolerance of protruded radicles. Surprisingly, survival of the germinated seed did not depend on re-establishment of desiccation tolerance in the protruded radicle. Even after the protruded radicle became necrotic and died, the production of adventitious roots from the hypocotyls allowed for survival and the development of high quality seedlings. Thus, T. impetiginosa appeared to be well adapted to the seasonally dry biome in which the species thrives via mechanisms that offer protection against desiccation in the young seedling stage.