Variability of the Chemical Composition of the Essential Oil from the Amazonian Ishpingo Species (Ocotea quixos).

Ocotea quixos (Lam.) Kosterm. is an aromatic tree native to Ecuador, whose leaves are used to prepare aromatic beverages to which different health benefits are attributed. In this study, Ocotea quixos leaves were collected in the Amazon region in different environmental conditions and subjected to hydrodistillation to isolate the essential oil. The collection variables used were type of soil, amount of shade, and height; in addition, the presence of twig and leaf age and moisture were used as variables. Chemical composition was analyzed by means of gas chromatography equipped with a flame ionization detector and gas chromatography coupled to mass spectrometry. A wide variety of chemical compositions were detected in the samples. In total, forty-seven compounds were identified, which represented between 97.17% and 99.89% of the total composition. The constituents were mainly grouped into aliphatic sesquiterpene hydrocarbons (33.03-55.89%), other compounds (8.94-47.83%), and oxygenated monoterpenes (1.97-39.66%). The main constituents were found to be (E)-cinnamyl acetate (5.96-41.65%), (E)-methyl cinnamate (0.38-37.91%), and trans-caryophyllene (8.77-37.02%). The statistical analysis suggested the existence of two essential oil chemotypes and a direct correlation between environmental conditions and chemical composition of the essential oils.

Leaf size in three generations of a dioecious tropical tree, Ocotea tenera (Lauraceae): Sexual dimorphism and changes with age.

PREMISE OF THE STUDY: In dioecious species, selection should favor different leaf sizes in males and females whenever the sexes experience distinct environments or constraints such as different costs of reproduction. We took advantage of a long-term experimental study of Ocotea tenera (Lauraceae), a dioecious understory tree in Monteverde, Costa Rica, to explore leaf size differences between genders and age classes across generations. METHODS: We measured leaf size in adult trees in a natural population, in their adult F(1) offspring in two experimental populations, and in their F(2) offspring at the seedling stage. Individual trees were measured at various times over 20 yr. RESULTS: Leaves of female trees averaged 8% longer and 12% greater in area than those of males. Leaves were sexually dimorphic at reproductive maturity. Leaf size declined during the lifetime of most trees. Heritability estimates for leaf length were positive although not statistically significant (h(2) = 0.63, SE = 0.48, P = 0.095). CONCLUSIONS: We ruled out the ecological causation hypothesis for sexual dimorphism in leaf size because male and female trees co-occurred in the same habitats. Sexual dimorphism appeared not to result from genetic or phenotypic correlations with other traits such as height or flower size. Rather, females appear to compensate for higher costs of reproduction and diminished photosynthetic capacity by producing larger leaves. Additive genetic variance in leaf size, a prerequisite for an evolutionary response to selection for sexual dimorphism, was suggested by positive (although only marginally significant) heritability estimates.

Polyamines, IAA and ABA during germination in two recalcitrant seeds: Araucaria angustifolia (Gymnosperm) and Ocotea odorifera (Angiosperm).

BACKGROUND AND AIMS: Plant growth regulators play an important role in seed germination. However, much of the current knowledge about their function during seed germination was obtained using orthodox seeds as model systems, and there is a paucity of information about the role of plant growth regulators during germination of recalcitrant seeds. In the present work, two endangered woody species with recalcitrant seeds, Araucaria angustifolia (Gymnosperm) and Ocotea odorifera (Angiosperm), native to the Atlantic Rain Forest, Brazil, were used to study the mobilization of polyamines (PAs), indole-acetic acid (IAA) and abscisic acid (ABA) during seed germination. METHODS: Data were sampled from embryos of O. odorifera and embryos and megagametophytes of A. angustifolia throughout the germination process. Biochemical analyses were carried out in HPLC. KEY RESULTS: During seed germination, an increase in the (Spd + Spm) : Put ratio was recorded in embryos in both species. An increase in IAA and PA levels was also observed during seed germination in both embryos, while ABA levels showed a decrease in O. odorifera and an increase in A. angustifolia embryos throughout the period studied. CONCLUSIONS: The (Spd + Spm) : Put ratio could be used as a marker for germination completion. The increase in IAA levels, prior to germination, could be associated with variations in PA content. The ABA mobilization observed in the embryos could represent a greater resistance to this hormone in recalcitrant seeds, in comparison to orthodox seeds, opening a new perspective for studies on the effects of this regulator in recalcitrant seeds. The gymnosperm seed, though without a connective tissue between megagametophyte and embryo, seems to be able to maintain communication between the tissues, based on the likely transport of plant growth regulators.

Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions.

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 degrees C, the minimum or base temperature estimated was 11 degrees C and the maximum ranged between 33 and 42 degrees C. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions / Germinação de sementes de Ocotea pulchella (Nees) Mez (Lauraceae) em laboratório e em ambiente natural de Restinga

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 ºC, the minimum or base temperature estimated was 11 ºC and the maximum ranged between 33 and 42 ºC. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

É apresentada a germinação de sementes de Ocotea pulchella (Nees) Mez em resposta a: luz, temperatura, nível de água e presença de polpa. Os ensaios de laboratório foram realizados em câmaras de germinação e em equipamento de gradiente térmico, e os de campo, em ambientes com diferentes condições de luz, temperatura e umidade no solo, em uma parcela permanente em floresta de Restinga no Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. As sementes de Ocotea pulchella não possuem dormência, são afotoblásticas, e a perda de viabilidade de sementes armazenadas a seco pode estar relacionada a um decréscimo no seu conteúdo de água. A presença da polpa e o substrato alagado afetaram negativamente a germinação de O. pulchella em laboratório. Luz e temperatura não são provavelmente fatores limitantes da germinação de sementes de O. pulchella no ambiente natural da Restinga. A faixa térmica ótima de germinação foi de 20 a 32 ºC; a temperatura mínima ou base foi estimada em 11 ºC; e a temperatura máxima variou de 33 a 42 ºC. As isotermas na faixa térmica infraótima exibem padrão sigmoidal e foram bem descritas pelo modelo de Weibull. A germinabilidade no sub-bosque, tanto em solo com maior umidade como em solo mais seco, foi maior do que em clareira. No sub-bosque não houve diferença na germinação em relação a variações na umidade do solo, ao passo que em clareiras a germinabilidade foi maior em solo mais úmido. Assim, a germinação dessa espécie deve ser função da interação de fatores, não podendo ser explicada apenas por um único fator.

Previous-year reproduction reduces photosynthetic capacity and slows lifetime growth in females of a neotropical tree.

Females of dioecious plant species typically invest more in reproduction than males because they produce seeds, fruits, and associated structures in addition to flowers. If females are unable to compensate by up-regulating rates of photosynthesis or by reproducing less frequently than males, their greater reproductive investment may result in reduced growth or higher mortality. Here we provide evidence of the cost of reproduction in Ocotea tenera (Lauraceae), a dioecious neotropical tree common in lower montane forests of Monteverde, Costa Rica. Over periods of 12-21 years, females grew more slowly than males in a natural population and in two experimental plots where we were able to control for genotype, age, habitat, and reproductive history. Simultaneous measurements of 10 matched pairs of sibling trees of the opposite sex but same age demonstrated that the photosynthetic capacities of females were 13% lower than those of males. Among females, photosynthetic capacity was negatively correlated with fruit production during the most recent reproductive season but not with lifetime fruit production. Sexual size dimorphism in adult O. tenera trees appears to be a nonadaptive consequence of trading off recent reproduction against maintenance of the photosynthetic apparatus, with long-term negative effects on growth.