Objetivou-se neste trabalho avaliar a densidade de plantio, a mortalidade e o incremento periódico anual (IPA) do crescimento em diâmetro e em altura das espécies empregadas no reflorestamento de áreas de restauração florestal, após a lavra de minério em unidade de conservação na Amazônia. Foram também analisadas as práticas edáficas nas áreas de plantio. O monitoramento abrangeu um período de 13 anos (1996 a 2009), na Floresta Nacional de Saracá Taquera, em Porto Trombetas, PA. As espécies foram distribuídas em classes de mortalidade e de incrementos em diâmetro e em altura. Foi analisada a aptidão ecológica baseada na mortalidade e nos incrementos do crescimento, em diâmetro e em altura, das espécies do ecossistema artificial sob restauração. O incremento periódico anual do diâmetro foi classificado como de graus ótimo, alto, baixo e muito baixo, envolvendo, respectivamente, 7, 17, 44 e 1 espécies. Analogamente, quanto à altura, foram classificadas 7, 33, 20 e 9 espécies, respectivamente. A aptidão ecológica das 69 espécies presentes, durante os 13 anos do monitoramento, identificou 24 espécies classificadas como inaptas, 21 como de baixa, 25 como regular, 16 como boa e apenas três como de ótima adaptabilidade. As práticas de caráter edáfico devem ser revistas, por apresentar indícios de estarem influenciando fortemente a mortalidade e desenvolvimento das árvores plantadas nas áreas de restauração.
A new species, Croton ascendens, is described as the second liana in its genus from South America. The new species is distinguished from Cro¬ ton pullei, the other liana in the genus described from Surinam, by its palmately lobed leaves, bisexual racemes in inflorescences, and slightly cucullate linear-spatulate petals of staminate flowers. Croton as¬ cendens is placed in section Croton, subsection Cro¬ ton .
Two new species of Croton are de¬ scribed from Amazonian Brazil, Croton diasii and C. trombetensis. Croton diasii is superficially similar to C. schiedeanus, but differs in having leaves with sparse lepidote scales on the lower surface, the up¬ per surface glabrous, a pair of glands at the base of the blade, lack of petals in the pistillate flowers, and stamens densely villous on the lower half of the filaments. Croton trombetensis, which lacks a close affinity to any other Croton from the Brazilian Amazon, is characterized by leaves with a dense indument of stellate trichomes on both sides, a cor¬ date base, long acicular stipules, a robust terminal thyrse 40-46 cm long, staminate flowers in fascic¬ ulate cymules, and pistillate flowers mixed among the staminate ones.Resumo. Duas novas especies da Amazonia Brasileira, Croton diasii e C. trombetensis, sao descritas. Croton diasii d superficialmente semelhante a C. schiedeanus, mas separa-se por apresentar folhas com tricomas lepidotos esparsos na face abaxial, a face adaxial glabra, um par de glandulas na base do limbo, ausencia de petalas na flor pistilada e estames densamente vilosos atd a metade do filete. Croton trombetensis nao apresenta afinidades elaras com nenhuma outra especie da Amazonia Brasileira, e caracteriza-se pelas folhas com denso indumento de tricomas estrelados em ambas as faces, base cordada, longas estfpulas aciculadas, inflorescencia em tirso terminal, robusta (40-46 cm de comprimento), as flores estaminadas em fasctculos e as pistiladas misturadas com as estaminadas.
The essential oil of Scleria hirtella was obtained by hydrodistillation and analysed by GC and GC-MS. The major constituents were nonanal (42.0%), geranial (25.3%) and neral (15.3%). It is a remarkable essential oil presenting a series of aliphatic aldehydes between C-7 and C-15, where the C-9 derivative is the most prominent. The aldehydes were probably generated from the oxidation of polyunsaturated fatty acids by plant enzymes. posited at Herbarium of Museu Emílio Goeldi, Belém, Brazil. The plant was dried at room temperature for 5 days and submitted to hydrodistillation for 4 h, using a Clevenger apparatus. The resulting oil (yield 1.9%) was dried over anhydrous sodium sulphate. Analysis of the Volatile ConstituentsThe oil analysis was performed on a Finnigan Mat INCOS XL GC-MS instrument under the following conditions: WCOT DB-5 fused silica capillary column (30 m × 0.25 mm, 0.25 µm film thickness); temperature programme, 60-240°C at 3°C/min; injector temperature, 220°C; carrier gas, He, adjusted to a linear velocity of 32 cm/s (measured at 100°C); injection type, splitless (1 µL hexane solution); split flow, adjusted to give a 20:1 ratio; septum sweep, constant 10 mL/min; EIMS, electron energy, 70 eV; ion source temperature and connection parts, 180°C.Quantitative data on the volatile constituents was obtained by peak area normalization, using a HP 5890 GC/FID instrument, operated under the same GC-MS conditions, except for the carrier gas, which was hydrogen produced by a Packard hydrogen generator.Individual components were identified by comparison of both mass spectra and GC retention data with those of authentic compounds previously analysed and stored in the data system. Other identifications were made by comparison of the mass spectra with those existing in the data system libraries and cited in the literature. 4 The retention indices were calculated for all volatile constituents using a homologous series of n-alkanes.
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