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RESUMOO presente trabalho foi realizado visando avaliar a viabilidade de grãos de pólen armazenados das cultivares copas cítricas Natal, Pêra e Valência. O pólen foi submetido a 3 temperaturas de armazenamento: -10 º C (freezer), 4 º C ( refrigerador) e temperatura ambiente; 2 ambientes (com e sem dessecador) e na presença e ausência de sílica-gel. A avaliação do índice de germinação foi feita com o pólen fresco e a cada 7 dias, durante 9 semanas. Para avaliar a germinação foi utilizado meio constituído de 1% de ágar e 10% de sacarose, 800 mg L -1 de nitrato de cálcio (Ca(NO 3 ) 2 4H 2 O), 200 mg L -1 de Ácido Bórico (H 3 BO 3 ) e pH corrigido para 6,5. Os grãos de pólen foram incubados à temperatura de 25 ± 2°C por 12 horas. As avaliações foram realizadas através da porcentagem de grãos de pólen germinados. Constatou-se que os grãos de pólen possuem redução na viabilidade com o aumento do tempo de armazenamento; o armazenamento em freezer (-10 o C) foi mais eficiente do que em refrigerador (4 o C) e à temperatura ambiente. Melhores resultados foram alcançados com os tratamentos em freezer com sílica-gel dentro de dessecador e em freezer sem sílica-gel dentro de dessecador. A cultivar Valência apresentou-se superior às demais em todos os tratamentos. Termos para indexação:Citrus sinensis , Palinologia, cultura de tecidos, melhoramento genético. ABSTRACTThe present work was accomplished to evaluate the effects of storage on the viability of pollen grains from Natal, Pêra and Valência cultivars of sweet oranges. The grains were stored at 3 temperatures: -10ºC (freezer), 4ºC (refrigerator), and room temperature; 2 environments (with or without desiccator) and in the presence or absence of silica-gel. The germination was evaluated every 7 days, during 9 weeks. To evaluate the germination, a medium consisting of 1% and sucrose 10%, 800 mg L -1 calcium nitrate (Ca(NO 3 ) 2 4H 2 O), 200 mg L -1 boric acid (H 3 BO 3 ) and pH 6,5 was used. The pollen was incubated at 25 ± 2°C temperature for 12 hours. The evaluation was performed using the percentage of pollen grains germinated. It was observed that pollen grains viability diminished as the storage time increased; the storage in freezer temperature (-10 º C) was much more efficient than in refrigerator (4 º C) and in room temperature. The best results were reached when freezer and desiccator were used. Valência cultivar was superior when compared whit the others, in all treatments.

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RESUMOA micropropagação da amoreira-preta pode gerar plantas livres de vírus e em curto espaço de tempo. Com o objetivo de aprimorar técnicas de propagação in vitro de amoreira-preta (Rubus sp.), testaram-se concentrações de meio MS e BAP. Gemas axilares com cerca de 2 cm, de plântulas pré-estabelecidas in vitro da cultivar Ébano, oriunda da Embrapa Clima Temperado/CPACT-Pelotas, RS, foram excisadas e inoculadas em meio MS (0, 50, 100, 150 -1 e fotoperíodo de 16 horas, avaliando-se número de folhas, número e comprimento dos brotos, número de raízes, peso da matéria fresca e seca da parte aérea. Melhores resultados foram obtidos em meio MS 150%, em que foi observado maior número de folhas (7,89) e de brotos (3,99), acrescidos de 1 mg L -1 de BAP. Na ausência de reguladores de crescimento, o número de raízes apresentou melhor desenvolvimento, sem a formação de calos.Termos para indexação: Rubus sp., BAP, meio de cultura MS. ABSTRACTWith ). The pH was adjusted for 5,8 before adding 6 g L -1 agar and before the esterilization at 121ºC and 1 atm for 20 minutes. After the inoculation, the explants were maintained by 60 days, in growth room, 27±1ºC, 35 μM m -2 s -1 and photoperiod 16 hours. The experiment was randomized complete blocks, using three explants by repetition. Better results were obtained with 150% MS medium, where the largest number (7,89) and sprouts (3,99) were observed, added of 1 mg L -1 de BAP. In the absence of BAP the number of roots had presented better development, without the callus's formation.

In vitro conservation techniques can be utilized for germplasm maintenance. However, few reports on the in vitro conservation of sugarcane species are present in the literature. The objective of this study was to subject sugarcane plants to in vitro under minimal growth conditions and to evaluate the survival, regeneration, and the monitoring of nuclear DNA content levels of the plants. Shoots from 10 sugarcane varieties (Saccharum spp.) were introduced into two media: MC1, consisting of half-strength Murashige and Skoog (MS) salts and 3% sorbitol, or MC2, similar to the first formulation, but additionally supplemented with 3.8 μM abscisic acid (ABA). The shoots were maintained for up to 12 mo at 18°C in the presence of light. At the end of the period, the explants were inoculated onto multiplication medium containing 0.9 μM 6-benzylaminopurine (BAP) and 0.47 μM kinetin (Kin) for growth recovery. Flow cytometry analysis of shoots was verified at every 6 mo of storage. As a result, we found distinct behaviors of the varieties studied over the storage time, but in general, MC1 provided the greatest explant survival rates, with an average of approximately 80% cultures being able to recover. Once in the recovery media, the explant regrowth was fast, and the ability to multiply shoots was reestablished from the second 30-d subculture. However, by flow cytometry analysis, we observed a decrease in the estimated relative amount of DNA at 12 mo storage for most varieties examined, which was not observed when the monitoring was done at 6 mo. From these results, we conclude that sugarcane plants survived the minimal growth condition; however, maintaining the genotypes for extended periods in vitro may lead to variations in the estimated amount of nuclear DNA and, thus, be at risk of somaclonal variation.

Annona crassiflora Mart known as 'araticum', 'marolo' or 'field araticum' is a typical fruit from the Cerrado biome of Brazil with socio-economic and medicinal importance. Normally, Annona crassiflora is propagated through seeds. However, due to a deep dormancy that the seeds display at dispersion and the difficulty to obtain uniform plants in a short time period, micropropagation may be a feasible alternative. Concentrations of gibberellic acid (GA3) and naphthalene-acetic acid (NAA) and their interactive effects on in vitro seed germination and seedling development of Annona crassiflora were studied. Mature fruits of Annona crassiflora were depulped and the seeds washed in clear water and dried at room temperature. Seed coat was removed and the seeds were placed on Murashige & Skoog (MS) medium supplemented with gibberellic acid (GA3) and naphthalene-acetic acid (NAA), 30 g L-1 sucrose and 6 g L-1 agar-agar. Seeds were kept under these conditions for 30 days. After this period, seedlings were kept for another 90 days on Wood Plant Medium (WPM) with 20 g L-1 sucrose and 5 g L-1 agar-agar supplemented with the same GA3 and NAA concentrations. Cultures were incubated under controlled conditions at 25 ± 2°C temperature, 16: 8 (light: dark) photoperiod of 32 µmol m-2 s-1 irradiance provided by cool white fluorescent tubes (Philips). Use of WPM medium supplemented with 25-32 mg L-1 GA3 or MS with 26-30 mg L-1 GA3 and 2 mg L-1 NAA promoted rooting and plant growth.

RESUMOAdição de carvão ativado e giberelina no meio de cultura podem proporcionar melhores condições no desenvolvimento de embriões imaturos de citros. Objetivou-se avaliar o efeito de carvão ativado e GA 3 (ácido giberélico) no cultivo de embriões imaturos provenientes do cruzamento entre laranjeira Pêra Rio x tangerineira Poncã . Após 118 dias da polinização, frutos imaturos, com 3 a 4 cm de diâmetro, foram coletados, suas sementes removidas e tratadas com álcool (70%) por cinco minutos, hipoclorito de sódio (2%) por 20 minutos e, posteriormente, lavadas três vezes em água destilada e autoclavada. Em condições assépticas, os tegumentos das sementes foram separados, os embriões globulares excisados e inoculados em tubos de ensaio contendo 15 mL do meio MT, acrescido de carvão ativado (0; 0,5; 1; 1,5 e 2 g L . Maior comprimento da parte aérea foi obtido em meio MT, acrescido de 0,1 e 1 mg L -1 de GA 3 , combinado com 2 g L -1 de carvão ativado. Maior comprimento do sistema radicular, massa da matéria fresca e número de folhas de plântulas foram obtidos em meio MT, acrescido de 0,01 mg L -1 de GA 3 , na ausência de carvão ativado. A adição de carvão ativado influenciou na concentração de ácido giberélico acrescido no meio de cultura. Termos para indexação:Citrus sinensis, Citrus reticulata, cultura de embriões. ABSTRACTActivated charcoal and gibberelin provides better conditions on development of citrus immature embryos. Activated charcoal and GA 3 (gibberelic acid) on Pêra Rio sweet orange x Poncã mandarin immature embryos culture was evaluated. After 118 dayspollination, imature fruits with 3 to 4 cm of diameter were collected, seeds removed and treated with alcohol (70%) for five min., sodium hypoclorite (2%) for 20 min. and three times washed with distilled and autoclaved water. In aseptic conditions, the teguments were separated, the globular embryos excised and inoculated in test tubes containing 15 mL of the MT medium culture, added of activated charcoal (0; 0.5; 1; 1.5 and 2 g L -1 ) and GA 3 (0; 0.01; 0.1; 1 and 10 mg L -1 ). After inoculation, the embryos were maintained for 90 days in growth room at 27±1ºC, 16 hours photoperiod and 32 mmol m -2 s -1 irradiance. Higher length of the aerial part was obtained in MT medium added 0.01 and 1 mg L -1 of GA 3 combined with 2 g L -1 of activated charcoal. Higher length of the roots system, fresh mass and number of leaves of seedlings was obtained in MT medium added 0.01 mg L -1 of GA 3 and activated charcoal absence. Addition of activated charcoal influenced in giberellic acid concentration added in MT medium.

RESUMO O objetivo deste trabalho foi avaliar o efeito de diferentes fontes de silício durante a fase de enraizamento