Deforestation in the Amazon Basin is still increasing, and the rehabilitation of these lands continues to be a challenge. Autoecological studies of most Amazonian species are rare, and efficient techniques for restoration of forested habitats have yet to be developed. The aim of this study was to test direct sowing as a rehabilitation technique for sites with different degrees of disturbance: bare soil, pasture, and secondary and mature forests in Central Amazonia, Brazil. At each site, we sowed seeds of 11 native tree species. Throughout the following year we evaluated germination and seedling survival. The germination differed according to the study site and species. Seedling survival in degraded sites was higher than in other areas. After 1 year in the bare soil site, 33% of the sown seeds of eight species developed seedlings; in the pasture the establishment was 23%, in secondary forest 15%, and in mature forest 12% of only four species. The only widespread survivor with more than 45% emergence in all perturbed sites was Caryocar villosum. No pioneer seedlings remained after 1 year. There was a positive correlation between seed size and survival. Large‐seeded non‐pioneer species seem to be more suitable for direct sowing than small‐seeded species. We recommend a combination of direct sowing and planting of seedlings as an appropriate means to accelerate the rehabilitation of degraded areas in Central Amazonia.

RESUMOO objetivo deste trabalho foi reunir informações sobre espécies madeireiras de terra firme nas proximidades de Manaus e tentar identificar as suas possíveis posições no contexto da sucessão florestal. Uma classificação facilitará modelar a dinâmica da floresta para apoiar a conservação, o manejo florestal e a reabilitação de áreas degradadas. O grupo estudado foi formado por 60 espécies botânicas pertencentes a 42 gêneros e 18 famílias. Em uma visão geral observaram-se sementes grandes >0,5cm3 (69% das espécies estudadas), predominância da dispersão zoocórica (60%), germinação em um período de até três meses (69%) e densidade elevada da madeira (>0,8g/cm3 em 52%). O conjunto das características utilizadas não foi adequado para classificar todas as espécies, pois características consideradas como típicas para pioneiras, ou clímax, foram observadas na mesma espécie em 24 das árvores selecionadas (40%). A densidade da madeira e a regularidade de frutificação apresentaram pouca utilidade na classificação, como também a presença de dormência nas sementes, pois há dormência em espécies de todas as fases sucessionais. Porém, a distinção entre os diversos tipos de dormência permitiu a separação dos grupos. Sugerem-se, para uma classificação mais robusta, os seguintes critérios ligados a semente: tipo de dispersão, quantidade das reservas, tolerância ao dessecamento e tipo de dormência. A tentativa de classificação das espécies madeireiras evidenciou que a maioria apresentou o conjunto das características típicas do estádio final da sucessão florestal. Porém, poucas apresentaram características de estádios mais iniciais da sucessão, e possuem provavelmente maior resistência às perturbações florestais. PALAVRAS-CHAVEsucessão florestal, pioneiras, oportunistas, climax, sementes.Basic characteristics for a preliminary ecological ranking of timber species occurring in a non-flooded forest in Central Amazonia. ABSTRACT The aim of this study was to gather information on timber trees occurring in a non-flooded forest near Manaus and to make an attempt to rank these species according to their succession in the forest. The ranking would be helpful in modeling the forest's dynamics, for forest conservation, management and rehabilitation of degraded areas. The group studied was formed by 60 botanical species belonging to 42 genera and 18 families. In a general view, seed size was >0.5cm3 (69% of the species), seed dispersal by animals predominated (60%), germination occurred within a period of up to 3 months (69%) and wood density was high (>0.8 g/cm3 in 52%

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The aim of this study was to evaluate the in vitro germination of zygotic embryos and seeds of Caesalpinia ferrea Martius and the morphogenetic responses of the explants to different concentrations of growth regulators. Seeds and zygotic embryos were inoculated in MS culture medium and kept in a growth room at a temperature of 25 ± 2 ºC for 16 hours of photoperiod for 30 days. The seeds had a higher in vitro germination rate than the explants from zygotic embryos. However, zygotic embryos in MS medium supplemented with 0.9 mg L-1 BAP had the highest percentage of regeneration (50%), number of shoots (3.25), buds (2.85) and leaves (3.15), multiplication rate (27.75), and length of shoots (1.96 cm). The in vitro culture of zygotic embryos and seeds made possible the multiplication of a higher number of healthy seedlings. Thus, it can be used as an alternative technique for the propagation of this species.

The objective of this work was to establish a protocol for the rapid in vitro multiplication of Caesalpinia ferrea Mart., aimed at genetic selection and in vitro germplasm conservation. Seeds treated in different sodium hypochlorite solution concentrations were inoculated in Murashige and Skoog (MS) culture medium and maintained in a growth room. After 30 days, sodium hypochlorite at 0.25% concentration resulted in 96.67% survival and 90% germination of the seeds. In the explants multiplication phase three types of medium culture were evaluated supplemented with cytokinins and auxins in different concentrations and combinations. The addiction of 0.1 mg·L-1 Benzylaminopurine (BAP) and 0.1 mg·L-1 Indole butyric acid (IBA) induced 100% of explants with shoots and 32% with root formation, while a complete absence of callus was found. It was observed that 90% of explants derived from the buds developed shoots with 2.73 cm and greater multiplication rate (10.06). The seedlings obtained from in vitro multiplication were acclimated without the presence of roots in different types of substrate. After 60 days, soil substrate was most indicated for acclimatization, showing 63.33% of healthy and uniform plants. In vitro propagation of C. ferrea allows the establishment and multiplication of in vitro seedlings from nodal segments and axillary buds.

Senna alata (Sin. Cassia alata), has been considered a promising species for the development of phytotherapy products, and it is necessary to supply biological material with high genetic quality for the pharmacology. Thus, the objective of the study was to evaluate the stimulating effects of plant growth regulators on callus formation of Senna alata. Nodal and leaf segments were inoculated in MS medium supplemented with different concentrations of 2,4-D (0; 2.21; 4.42; 6.63 and 8.84 mg L-1) under the influence of LED light (white and colored) and darkness. It was also evaluated the effect of 2,4-D (1.0 mg L-1) in combination with TDZ and BAP in the concentration of 1.0, 3.0 and 5.0 mg L-1 in the presence and absence of activated charcoal for callus induction. The percentage of responsive explants and/or callus formation was evaluated after 4 weeks of culture. The results showed that the conditions of white LED are favorable for callus induction in leaf explants (77.5%) and nodal explants (90.0%). In addition, the interaction of 2,4-D with cytokinins was also favorable for the development of callus. However, activated charcoal did not favor the process of callogenesis. This study concludes that the production of friable callus can be obtained from axenic tissue of S. alata.

Libidibia ferrea (Fabaceae) is a valuable medicinal species in the Amazon, but as it is a protected plant, collection from natural populations is forbidden. Therefore, establishing an efficient system for in vitro regeneration and to improve callogenesis of this species is desirable. To determine the optimal nutritional factors needed for shoot multiplication and callus induction, different culture media, plant growth regulators and LED light sources were tested. The data were subjected to analysis of variance (ANOVA) and means compared by Tukey’s test at p < 0.05. We observe that explants inoculated in the Murashige and Skoog (MS) media with 0.05 mg L-1 of 6-benzilaminopurine (BAP) and cultivated under red-blue LED induced the highest number of shoots (3.67), number of buds (3.13), multiplication rate (15.67) and shoots length (22.03 mm) when compared with other treatments. MS and B5 media supplemented with 2.21 and 4.42 mg L-1 of 2,4-D induced 100% formation of friable callus cultivated under red-blue LED, demonstrating that the light quality significantly influenced callogenesis. Obtained results confirmed that in vitro regeneration and callogenesis is a useful strategy in the protection of endangered species. In this way, a new renewable source of biomass with high quality plant material is presented aiming at the bioprospecting of seedling extracts and friable callus to obtain secondary metabolites of this medicinal plant.

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