Seed size influence on germination responses to light and temperature of seven pioneer tree species from the Central Amazon.

In Amazon secondary forests are dominated by pioneer species that typically produce large amounts of small and dormant seeds that are able to form a persistent soil seed bank. Seed dormancy in this group of species is overcome by environmental conditions found in open areas, such as high irradiation or alternating temperatures. Nevertheless, a variety of germination responses to environmental factors is known among pioneers; some of them may germinate in diffuse light or in darkness condition at constant temperature. Seed mass can be considered as one of the factors that promotes this variety. Regarding species with very small seeds, it seems that the trigger for germination is light and for larger seeds temperature alternation may be a more important stimulus. In this study we established a relationship between seed mass and germination response to light and alternating temperature for a group of seven woody pioneer species from the Amazon forest. We found that an increase in seed mass was followed by a decrease in the need for light and an increase in the tolerance to alternating temperatures. Understanding germination strategies may contribute with the knowledge of species coexistence in high diverse environments and also may assist those involved in forest management and restoration.

Constituintes das sementes de Copaifera officinalis L / Constituents from Copaifera officinalis L. seeds

O gênero Copaifera L. é um dos mais importantes economicamente na Região Amazônica devido, principalmente, à produção dos óleos de copaíba, oléo-resinas com diversas propriedades farmacológicas confirmadas. Apesar disso, os estudos fitoquímicos com as sementes das árvores do gênero Copaifera L.são raros. Copaifera officinalis foi a primeira espécie do gênero Copaifera a ser descrita. Este trabalho descreve a composição dos extratos obtidos em hexano e em acetato de etila das sementes de C. officinalis. No extrato obtido em hexano, a análise por cromatografia em fase gasosa utilizando padrões e através de espectrometria de massas permitiu a identificação de: esqualeno, tetradecano, hexadecano, campesterol, estigmasterol e beta-sitosterol; os ácidos graxos hexadecanóico, 9-octadecenóico e octadecanóico (majoritários); e decanóico, eicosanóico, docosanóico e tetracosanóico (minoritários). Cumarina foi isolada do extrato em acetato de etila e identificada por técnicas de RMN.

Copaifera L. is one of the most economically important plant genera in the Amazon Region, since it exudes a resin-oil named copaiba oil possessing several confirmed pharmacological properties. In spite of that, phytochemical studies of the seeds from this genus are rare. Copaifera officinalis L. was the first species in the genus Copaifera to be described. This paper describes the chemical composition of the hexane and ethyl acetate extracts of the seeds from this species. In the hexane extract, gas chromatography and mass spectrometry analyses enabled us to identify squalene, tetradecane, hexadecane, campesterol, stigmasterol and beta-sitosterol; hexadecanoic, 9-octadecenoic and octadecanoic acids (major substances); as well as decanoic, eicosanoic, docosanoic and tetracosanoic (minor substances) acids. Coumarin was detected in the ethyl acetate extract, isolated and identified by NMR.