Regina Caetano Quisen

Plant regeneration from cotyledonary explants of Eucalyptus camaldulensis dehn and histological study of organogenesis in vitro

The present work aimed at regenerating plants of Eucalyptus camaldulensis from the cotyledonary explants and describing the anatomy of the tissues during callogenesis and organogenesis processes, in order to determine the origin of the buds. The cotyledonary leaves of E. camaldulensis were cultured in Murashige and Skoog (MS), WPM and JADS media supplemented with 2.7 µM NAA and 4.44 µM BAP. The best results for bud regeneration were obtained on MS and WPM media (57.5 and 55% of calluses formed buds, respectively). Shoot elongation and rooting (80%) were obtained on MS/2 medium (with half-strength salt concentration) with 0.2% activated charcoal. Acclimatization was performed in the growth chamber for 48 h and then the plants were transferred to a soil:vermiculite mixture and cultured in a greenhouse. Histological studies revealed that the callogenesis initiated in palisade parenchyma cells and that the adventitious buds were formed from the calluses, indicating indirect organogenesis.

Selective agent and A. tumefaciens overgrowth-control antibiotics in Eucalyptus camaldulensis Cotiledonary culture

The objectives of the present work were to establish the minimal lethal dose of the selective agent to determine the type and concentration of appropriate antibiotics for the elimination of Agrobacterium tumefaciens inoculated explants, without interfering with the regenerative potential of the E. camaldulensis cotyledonary explants. Non-transformed explants were cultivated in medium supplemented with kanamycin. The results showed that the antibiotic was suitable for the selection of transformed cells in the concentration of 9 mg L-1 as it inhibited the growth of non-transformed cells. Cotyledons infected with A. tumefaciens were cultivated in MS N/2 medium supplemented with BAP, ANA, Km and cefotaxime or AugmentinO . The highest average of regenerated shoots by explant (5,4) was observed in the presence of 300 mg L-1 of AugmentinO /15 days, followed by 150 mg L-1/15 days and 100 mg L-1/30 days.

RAPD em Pau-rosa (Aniba rosaeodora Ducke): adaptação do método para coleta de amostras in situ, ajuste das condições de PCR e apresentação de um processo para selecionar bandas reprodutíveis

Rosewood (Aniba rosaeodora Ducke) is one of the economically valuable species in the Amazon region, because it is the principal source of linalool which is demanded by the perfumery industry. This species was submitted to hard exploitation along the past decades and besides this almost nothing is known about its intraspecific genetic diversity. The objectives of this work were: 1) to validate a method to collect rosewood leaves, while preserving the integrity of DNA until storage in freezer; 2) to choose a method for extraction of nucleic acids in quantity and with quality good enough to be used for RAPD and 3) to develop criteria for evaluating the reproducibility, which could help to select RAPD bands useful for genetic diversity analysis. Immediately following collection, the leaves were put in PET flasks partially filled with silica gel and kept there up to 10 days. Three methods for extracting nucleic acids from those leaves, the PCR conditions and the reproducibility of the RAPD patterns produced were tested. Criteria for elimination of bands that contributed to maintain reproducibility away from the ideal, which would be total reproducibility, were developed and the differences produced by application of these criteria were statically tested. DNA with sufficient quality to generate RAPD patterns under the improved conditions defined for the PCRs was obtained. Elimination of bands with reproducibility below 70% did not differ from control. Elimination of bands with reproducibility below 90% differed from all the other treatments tested (P < 5%).

Geographic pattern of genetic diversity in natural populations of Rosewood (Aniba rosaeodora), in the Central Amazonia

AbstrAct Rosewood ( Aniba rosaeodora Ducke, lauraceae) is an amazonian evergreen tree and a source of the purest linalool, the main component of its essential oil, which is very valuable in the international perfumery market. after decades of over-exploitation it is currently considered as threatened. We evaluated the genetic diversity and its distribution in four populations in Central amazonia. thirty-five reliable RaPD markers were generated, of which 32 were polymorphic (91.4%). variation was higher within the populations (76.5%; p < 0.0001) and geographic distribution contributed to population differentiation (23.4%; p < 0.0001). the amazon River had a small influence on gene flow (3.3%; p < 0.0001), but we identified evidence of gene flow across the river. there were significant differences in marker frequencies (p < 0.05), in agreement with the low gene flow ( Nm = 2.02). the correlation between genetic distance and gene flow was - 0.95 (p = 0.06) and between geographic distance and gene flow was -0.78 (p = 0.12). there was a geographic cline of variability across an east-West axis, influenced as well by the amazon River, suggesting the river could be a barrier to gene flow. although threatened, these Rosewood populations retain high diversity, with the highest levels in the manaus population, which has been protected for over 42 years in a Reserve.

Teste de tetrazólio em embriões de sementes de dendezeiro

O teste de tetrazolio (TZ) em dendezeiro pode ser uma ferramenta util para verificar o vigor e viabilidade das sementes. O objetivo foi determinar procedimentos para uso do TZ na analise de vigor e viabilidade de embrioes e da aplicacao deste na avaliacao do potencial de germinacao das sementes de dendezeiro.

In vitro germination of zygotic embryos of hybrid BRS Manicoré (E. guineensis X E. oleifera)

The interspecific oil palm hybrid BRS Manicoré (E. guineensis x E. oleifera) has superior agronomic characteristics. However, the germination rate is low (30%) and the process is slow when the seeds are sown in a conventional form. The purpose of this study was to optimize the in vitro germination of zygotic embryos of this hybrid comparing seed lots. The viability of zygotic embryos was evaluated by the tetrazolium test (0.075%) for 4 h. The embryos were cultured on MS and Y3 culture media, with and without the addition of NaH2PO4, as well as on MS, MS1/2 and N6 medium. In MS medium containing NaH2PO4, the germination rate was increased from 40 to 70% in comparison with the medium without sodium phosphate. The comparison between the culture media MS, MS 1/2, N6 and Y3 showed that 75% of zygotic embryos cultured in the Y3 medium formed whole plants (with roots and shoots defined), a higher percentage than embryos cultured on MS, MS 1/2 and N6 media (46, 35 and 17% respectively). In the same Y3 culture medium, the embryos were larger (36% ≥ 2 cm and 30% ≥ 5 cm) than in the other media. Results obtained by the tetrazolium test were similar to those of germination, showing the effect of the genotype of each seed lot. For the germination and development of plantlets it is essential to add NaH2PO4 to a culture medium containing no phosphate or with a low phosphate concentration.