This study was carried out in a plantation of a degraded area in Central Amazon, Brazil, in order to assess environmental light effects on leaf pigment concentrations and chlorophyll a fluorescence in mahogany (Swietenia macrophylla King) and tonka bean (Dipteryx odorata Aubl. Willd). Three-year old saplings were grown in an open site (sun) with maximum radiation of approximately 2000 mumol m-2 s-1 and under the shade of a Ochroma pyramidale (Cav. ex Lam. Urb) canopy. A leaf area index of 2.46 was optically determined for the Ochroma foliage with 13% of full sunlight (maximum radiation about 260 mumol m-2 s-1). Carotenoid and chlorophyll concentrations were spectrophotometrically determined. Initial (Fo), maximum (Fm) and variable fluorescence (Fv) were determined with a portable fluorometer. Chlorophyll concentrations (Chl a, Chl b and Chl tot) on a fresh mass basis were greater in shade leaves than in sun acclimated leaves in both species. On the other hand, when comparisons were made on a per area basis, Chl a concentrations were greater in the sun than in shade leaves of tonka bean. In contrast, Chl b concentrations were higher in the shade environment for this species. No differences were observed in Chl concentrations per unit area in mahogany leaves. Carotenoid concentrations were higher for sun-acclimated leaves of mahogany, both on a per unit area and on a fresh mass basis. In tonka bean, higher carotenoid concentrations in shade leaves were only observed on a fresh weight basis. No differences were found between environments when carotenoid concentrations were expressed as a function of leaf area. Fluorescence variables (Fo, Fm, and Fv) were greater in sun leaves than in shade leaves of mahogany. In contrast, Fv and Fm, but not Fo, values were higher in shade acclimated leaves than in full sunlight-adapted leaves of tonka bean. However, there was a higher Fv/Fm ratio value for tonka bean in sunlight environments. We conclude that these species, classified as mid and late successional species, differ markedly regarding the utilization of photosynthetic pigments, increasing either light harvesting efficiency at low irradiance or protection against photosynthetic machinery damage in higher solar radiation environments.

Monoculture and mixed stands of mahogany (Swietenia macrophylla King) and tonka bean (Dipteryx odorata Willd.) trees were established on degraded land in central Amazonia to compare leaf gas exchange parameters between plants grown in sunlight in an open field and in shade beneath a balsa wood (Ochroma pyramidale Cav.) canopy. Shading increased specific leaf area by about 50% in both species. Shading reduced height and diameter growth of S. macrophylla, whereas it increased these parameters for D. odorata. Light-saturated photosynthesis (Amax), stomatal conductance (gs) and transpiration (E) were higher in S. macrophylla than in D. odorata. In S. macrophylla, Amax was higher in sun leaves (12.9 +/- 0.9 micromol m-2 s-1) than in shade leaves (10.2 +/- 1.0 micromol m-2 s-1), whereas light environment had no significant effect on Amax of D. odorata. In both species, CO2-saturated photosynthesis (Apot) was higher in sun leaves (22 +/- 1.4 micromol m-2 s-1) than in shade leaves (17-20 +/- 0.8 micromol m-2 s-1). Stomatal conductance and E increased in sun leaves of S. macrophylla by 45 and 38%, respectively, whereas light environment did not affect gs and E of D. odorata. Photorespiration rates (Pr) varied from 28 to 36% of net photosynthesis (A) at ambient atmospheric CO2 concentration (Ca) but declined to around 7% of A at higher Ca. Leaf dark respiration (Rd) and the CO2 compensation point (Gamma) were lower in shade-grown plants than in open-grown plants. Compared with shade-grown plants, total nonstructural carbohydrate (TNC) concentrations increased by 56% in S. macrophylla and by 30% in D. odorata in the open field. Leaf nitrogen (NL) concentrations were higher in open-grown plants than in shade-grown plants of both species, and TNC and NL concentrations were negatively correlated (r = -0.77). High TNC accumulation in S. macrophylla in the open field suggests that photosynthesis is unlikely to be growth-limiting at this site. We conclude that photosynthetic parameters of D. odorata are less affected by light environment than those of S. macrophylla, indicating that D. odorata has lower physiological plasticity to light than S. macrophylla.

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Óleos de copaíba são importantes produtos naturais que têm sido amplamente utilizados por suas atividades cicatrizantes e anti-inflamatórias. Constituídos de sesquiterpenos e diterpenos, estes óleos apresentam composição química variável que, segundo a literatura pode ser originada por diversos fatores bióticos e abióticos. Com o objetivo de analisar a relação entre a composição química e fatores abióticos como sazonalidade, diâmetro à altura do peito (DBH) e composição do solo, dezesseis amostras de óleo-resina de Copaifera multijuga Hayne, provenientes da Reserva Florestal Ducke (Manaus-AM, Brasil), foram analisadas por cromatografia gasosa com detector de ionização de chama (GC-FID) e acoplada à espectrometria de massas (GC-MS). Trinta e cinco substâncias foram identificadas e os resultados avaliados por técnicas de análise multivariada (análises de agrupamento hierárquico (HCA) e a análise de componentes principais (PCA)), permitindo a diferenciação das amostras em dois grupos com composições distintas. Um deles apresentou como substância majoritária b-cariofileno enquanto o outro apresentou o óxido de cariofileno, essa variação na composição parece depender do tipo de solo. Outros fatores, anteriormente descritos como essenciais para a definição da composição química dos óleos de copaíba, como sazonalidade e DBH, não mostraram influência significativa sobre a composição química dos óleos-resina desta espécie.Copaiba oils are important medicinal products used primarily for their healing and antiinflammatory activities. Consisting of sesquiterpenes and diterpenes, these oils have variable composition which, according to the literature, may originate from several factors. In order to analyze the relationship between chemical composition and abiotic factors such as seasonality, diameter at breast height (DBH) and soil composition, sixteen of oilresin samples of Copaifera multijuga Hayne, from the Ducke Forest Reserve (Manaus City, Amazon State, Brazil), were analyzed by gas chromatography with flame ionization detection (GC-FID) and coupled with mass spectrometry (GC-MS). Thirty-five compounds were identified and the results evaluated by multivariate analysis (hierarchical cluster analysis (HCA) and principal component analysis (PCA)), allowing differentiation of the samples into two groups with different compositions. One of them presented b-caryophyllene as the major constituent, while the other presented caryophyllene oxide. This variation in composition appears to depend on soil type. Other factors previously described as essential for defining the chemical composition of copaiba oils, such as seasonality and DBH, showed no significant influence on the chemical composition of oils of this species.Keywords: oilresins, chemical variability, multivariate analysis, seasonal influence, diameter at breast height, soil type Influence of Abiotic Factors on the Chemical Composition of Copaiba Oil (Copaifera multijuga Hayne) J. Braz. Chem. Soc. 1824 IntroductionThe genus Copaifera belongs to the family Fabaceae,...

Oils of various species of Copaifera are commonly found in pharmacies and on popular markets and are widely sold for their medicinal properties. However, the chemical variability between and within species and the lack of standardization of these oils have presented barriers to their wider commercialization. With the aim to recognize patterns for the chemical composition of copaiba oils, 22 oil samples of C. multijuga Hayne species were collected, esterified with CH2 N2 , and characterized by GC-FID and GC/MS analyses. The chromatographic data were processed using hierarchical cluster analysis (HCA) and principal component analysis (PCA). In total, 35 components were identified in the oils, and the multivariate analyses (MVA) allowed the samples to be divided into three groups, with the sesquiterpenes β-caryophyllene and caryophyllene oxide as the main components. These sesquiterpenes, which were detected in all the samples analyzed in different concentrations, were the most important constituents in the differentiation of the groups. There was a prevalence of sesquiterpenes in all the oils studied. In conclusion, GC-FID and GC/MS analyses combined with MVA can be used to determine the chemical composition and to recognize chemical patterns of copaiba oils.

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Studies on nutritional status and leaf traits were carried out in two tropical tree species Swietenia macrophylla King (mahogany) and Dipetryx odorata Aubl. Willd. . The parameters analysed were leaf area (LA), leaf dry mass (LDM), specific leaf area (SLA) and leaf nutrient contents. It was observed that, S. macrophylla leaves grown under full sunlight showed LA 35% lower than those grown under shade. In D. odorata leaves these differences in LA were not observed. In addition, it was observed that S. macrophylla shade leaves, for LDM, were 50% smaller than sun leaves, while in D. odorata, there differences were not observed. SLA in S. macrophylla presented that sun leaves were three times smaller than those grown under shade. In D. odorata, no differences were observed. Nutrient contents in S. macrophylla, regardless of their light environments, showed higher contents for P and Ca than those found in D. odorata. The N, K, Fe and Mn contents in S. macrophylla leaves decreased under shade. Finally, we suggest that the decreasing in leaf nutrient contents may have a negative influence on leaf growth. The results demonstrated that the tested hypothesis is true for leaf traits, which D. odorata, late-successional species, showed lower plasticity for leaf traits than Swietenia macrophylla, mid-successional species. KEY WORDStropical species, leaf traits, nutrients, forest succession.Estado nutricional e área foliar específica de mogno e cumaru sob dois ambientes de luz. RESUMO Estudou-se a nutrição mineral e as características foliares de duas espécies arbóreas tropicais PALAVRAS-CHAVEespécies tropicais, características foliares, nutrientes, sucessão florestal.

RESUMO & Bniòclilz apnzòzntou maicn númzho de zòpícizò aqnupadaò no& 4 tnatamzntoà, jã\ o Zndicz dz Payandzh. apnzòznt.ou maion numzfio dz Zòpzcizò não aghupada-í>. INTRODUÇÃOA Amazônia ocupa cerca de 40¾ do território nacional, sendo caracterizada pela am pia variabi1 idade de espécies florestais. Sua cobertura florestal tem sido alvo de uma exploração desordenada e se)et Uva em face da demanda por espécies de alto valor comercial.A fragilidade do ecossistema e a constante interferência humana impõem a necessidade de estudos sobre a composição flor'stica e o gregarismo de espécies para assegurar, através de projetos de manejo, a reposição de áreas exploradas.Trabalhos sobre a composição fl or fs t i ca e o gregarismo da regeneração natural em florestas tropicais sao escassos. Essas informações sao importantes para fornecer subsídios para projetos de manejo e enriquecimento do povoamento florestal com espécies de valor econômico.