Leila Aparecida Salles Pio

Viabilidade do pólen de laranjas doces em diferentes condições de armazenamento

O presente trabalho foi realizado visando avaliar a viabilidade de graos de polen armazenados das cultivares copas citricas Natal, Pera e Valencia. O polen foi submetido a 3 temperaturas de armazenamento: -10oC (freezer), 4oC ( refrigerador) e temperatura ambiente; 2 ambientes (com e sem dessecador) e na presenca e ausencia de silica-gel. A avaliacao do indice de germinacao foi feita com o polen fresco e a cada 7 dias, durante 9 semanas. Para avaliar a germinacao foi utilizado meio constituido de 1% de agar e 10% de sacarose, 800 mg L-1 de nitrato de calcio (Ca(NO3)2 4H2O), 200 mg L-1 de Acido Borico (H3BO3) e pH corrigido para 6,5. Os graos de polen foram incubados a temperatura de 25 ± 2oC por 12 horas. As avaliacoes foram realizadas atraves da porcentagem de graos de polen germinados. Constatou-se que os graos de polen possuem reducao na viabilidade com o aumento do tempo de armazenamento; o armazenamento em freezer (-10oC) foi mais eficiente do que em refrigerador (4oC) e a temperatura ambiente. Melhores resultados foram alcancados com os tratamentos em freezer com silica-gel dentro de dessecador e em freezer sem silica-gel dentro de dessecador. A cultivar Valencia apresentou-se superior as demais em todos os tratamentos.

In vitro seed germination and seedling development of Annona crassiflora Mart.

O araticum ou marolo (Annona crassiflora Mart.) e uma fruta tipica de Cerrado com grande importância socio-economico e medicinal. Sua propagacao pode ser feita atraves de sementes, porem devido a dormencia das sementes e dificuldade de se obterem plantas uniformes e em curto espaco de tempo, a micropropagacao podera ser uma alternativa. Estudaram-se os efeitos do GA3 associado ao ANA sobre a germinacao de sementes e desenvolvimento in vitro de marolo. Frutos maduros foram despolpados e suas sementes lavadas e secas. Em seguida retirou-se o tegumento das sementes e estas foram colocadas em tubos contendo 20 mL de meio MS, acrescido de GA3 e ANA. Ao meio foram adicionados 30 g L-1 de sacarose e 6g L-1 de agar, permanecendo nestas condicoes por 30 dias. Ao final dos 30 dias, as plântulas foram colocadas em meio WPM, acrescido de 20 g L-1 de sacarose, 5 g L-1 de agar e suplementado das mesmas concentracoes de GA3 e ANA da etapa anterior, onde permaneceram por 90 dias. Melhores resultados em meio WPM para todas as variaveis analisadas foram obtidos na faixa de 25-32 mg L-1 de GA3. Em meio MS a interacao significativa foi observada apenas no comprimento da parte aerea e numero de raizes, nos quais melhores resultados foram verificados com 26,92 - 30,13 mg L-1 de GA3 associado a 2 mg L-1 de ANA.

Multiplicação in vitro de amoreira-preta cultivar Brazos

With the objective of multiplying blackberry cv. Brazos, nodal segments, coming from in vitro plants previously selected, were excised and inoculated in WPM culture medium (0, 50, 100, 150 and 200%), supplemented with different concentrations of BAP (0; 0,5; 1,0; 2,0 and 4,0 mg L-1). After inoculation, the explants were transferred to culture room, at 27±1oC temperature, 35 mmol m2 s1 ofirradiance and photoperiod of 16 hours, for 60 days. The experimental was a design randomized complete block, with four replications and four explants each. Greater number of sprouts was provided with 1,0 mg L-1 of BAP associated with 100% WPM culture medium and larger sprouts length average after 60 days were verified in 1,0 mg L-1 of BAP associated with 200% WPM culture medium. Higher dry matter weight of the aerial part was obtained in 200% WPM culture medium added with 0,5 mg L-1 of BAP.

Cloreto de potássio e fosfato de sódio na multiplicação in vitro de amoreira-preta cv. Tupy

A micropropagacao da amoreira-preta pode gerar plantas livres de virus e em curto espaco de tempo. Com o objetivo de aprimorar tecnicas de micropropagacao de amoreira-preta cv. Tupy (Rubus spp.), segmentos nodais com cerca 2 cm e 2 gemas axilares, oriundos de plantas pre estabelecidas in vitro, foram excisados e inoculados em meio de cultura MS, suplementado com diferentes concentracoes de fosfato de sodio (0, 125, 250, 500 e 1000 mg L-1) e de cloreto de potassio (0, 125, 250, 500 e 1000 mg L-1). O pH foi ajustado para 5,8 antes da adicao de 6 g L-1 de agar e da autoclavagem a 121oC e 1 atm por 20 minutos. Apos a inoculacao, os explantes foram transferidos para sala de crescimento a 25 ± 1oC, irradiância de 35 mmol m-2 s-1 e fotoperiodo de 16 horas, onde permaneceram por 60 dias. O delineamento experimental utilizado foi inteiramente casualisado, utilizando-se de quatro repeticoes constituidas de tres tubos de ensaio contendo um explante cada. O numero de brotos e o comprimento da parte aerea das plantas foi menor em funcao de maiores concentracoes de cloreto de potassio. Melhores resultados foram obtidos na ausencia de KCl e na presenca de fosfato de sodio, principalmente para comprimento e materia fresca da parte aerea.

Prolongamento do período de colheita da tangerineira Ponkan com aplicação de GA3 e 2,4-D

This experiment was carried out on a ten year-old commercial orchard in Sao Joao Del Rei county-MG in order to extend the harvest season of tangerine Ponkan (Citrus reticulate Blanco). One evaluated the effects of Giberelic Acid (GA3) at 0, 10, 20 and 30 mg.0L-1 and Diclorofenoxiacetic acid (2,4- D) at 0 and 10 mg.L-1 applied two times: on 4/24 and 5/17 when the fruits still had a green peel color the evaluations were made: the first one on 7/25, when the harvest time in the region was ending, and the second 30 days after. The experimental design adopted was the one of randomized blocks, with a factorial of 4 x 2 x 2, with four split-plot replicates. The results showed that 2,4-D at 10 mg.L-1 influenced fruits texture and extended the harvest and also increased fruit acidity and reduced the ratio; GA3 at 20mg.L-1 increased the diameter and weight of the fruits harvested in August and presented higher juice rate and there was no difference on total soluble sugar in solid solute tenor.

Receptiveness of the stigma and in vitro germination of orange pollen, submitted to different temperatures

The study was carried out in order to evaluate the effect of temperature and in vitor stigma receptivity on regeneration of orange cultivar (Valencia, Pera and Natal) pollen. Two experiments were carried out, in the first the ideal temperature of germination was assessed. Pollen was obtained from flowers at the balloon stage and inoculated in culture medium with 10 g L-1 agar, 200 mg L-1 boric acid, 100 g L-1 sucrose, 800 mg L-1 calcium nitrate, pH adjusted to 6,5 and incubated in a BOD chamber at temperatures of 23, 24, 25, 26 and 27oC during a 24-hour photoperiod. After 12 hours of incubation, the best temperature for pollen grain germination was 25oC for all varieties. In a second experiment, in order to test the receptivity of the stigma, flowers were collected at different flowering stages: small bud, balloon and open flower. The stigmas were by immersion exposed to hydrogen peroxide (perioxidase reaction), 3% for 3 minutes. Through the technique of Zeisler (1938), better results were detected at the balloon stage with 80 to 100% receptivity, while for the open flower the receptivity presented maximum indexes.

Cloreto de sódio e ácido naftalenoacético no enraizamento de microestacas de amoreira-preta cv. Brazos in vitro

The blackberry (Rubus sp.) micropropagation is used, mainly for obtaining virus-free plants in short period of time. In the present work different concentrations of sodium chloride (NaCl) and naphthaleneacetic acid (NAA) were tested added to in vitro culture medium of blackberry cv. Brazos. The culture medium consisted of MS salts, with 30 g L-1 sucrose 6 g L-1 agar and pH adjusted to 5.8 before the sterilization at 121oC and 1 atm for 20 minutes. The treatments consisted of NaCl (0; 25; 50; 75 and 100 mg L-1) and NAA (0; 0.01; 0.5; 1.0 and 1.5 mg L-1) concentrations, in all possible combinations. Nodal segments, originating from plants established in vitro were excised and introduced in tubes containing 15 mL of culture medium. After that, the tubes were transferred to growth room at 25 ± 2oC, irradiance of 35 mmol m-2 s-1 and photoperiod 16 hours. A completely randomizel block design with four replicates and 12 plants per replicate was used. The experiment was evaluated after 70 days of in vitro cultivation. The in vitro development of the cv. Brazos was favored in the treatments with 50 to 75 mg L-1 NaCl and 1.0 to 1.5 mg L-1 NAA, while the best rooting results were obtained using 100 mg L-1 NaCl and 1.5 mg L-1 NAA.

Flow Cytometry Applied in Tissue Culture

Flow cytometry is a powerful technology that allows for the simultaneous analysis of multiple attributes of cells or particles in a liquid medium. The first cytometer used was built during World War II, when [1] developed an equipment where particles flowed through the system to diffuse light through a lens, producing electrical signals sensed by a photodetector. The instrument could detect objects in the order of ~ 0.5 μm in diameter, and is recognized as the first flow cytometer used for observation of biological cells [2]. This would be possible to identify aerosols, bacteria that would possibly biological warfare agents as well as check the efficiency of gas mask filters against particles. In 1950, the same principle was applied to the detection and enumeration of blood cells. As hematology and cellular immunology, two biological areas, that drove the development of flow cytometry [3]. Later, with improved equipment and methods, this technique was adapted to other areas of biology, including the plant kingdom [4]. Already in 1973 the German botanist Friedrich Otto Heller used the Impulszytophotometrie (pulse cytophotometry in German). This scientist did not imagine that it has launched a new field of scientific research, which would later be called flow cytometry in plants.

Caracterização morfológica de cultivares de bananeira micropropagadas em estádio juvenil

The aim of this study was to determine morphological descriptors that could enable the characterization of banana cultivars from micropropagation process during the juvenile phase. Twelve cultivars from different genomic groups and with different ploidy levels were grown in vitro and acclimatized in greenhouse for three months. After this period, plants quantitative morphological and descriptive characteristics were evaluated. The results allowed ranking the cultivars and preparing an analytical key to identify these cultivars after the period of three months of acclimatization.

Modificações morfoanatômicas e fisiológicas de maracujazeiro fertilizado com silício

The objective of this work was to evaluate the effect of silicon fertilization on gas exchange, leaf anatomy, and ultrastructural characteristics of passion fruit (Passiflora edulis). The treatments comprised four concentrations of silicon (0, 0.28, 0.55, and 0.83 g per pot) at 1% silicic acid solution (SiO2.XH2O). This solution was applied around the stems of the plants. The first application was made 15 days after seedlings were transplanted. In total, three applications were made at 15-day intervals. The pots that constituted the control treatment received water in the same amount. After the final application, the plants were subjected to analyses of gas exchange, anatomical changes, and ultrastructural characteristics. The use of silicon promotes anatomical changes in passion fruit seedlings, such as increased adaxial epidermis thickness, reduced palisade parenchyma, and increased polar diameter/equatorial diameter ratio, which is related to stomata functionality. The concentrations of 0.55 and 0.83 g silicon per pot provide higher rates of photosynthesis, of transpiration, and stomatal conductance. The concentration of 0.83 g silicon per pot results in the greatest deposition of silicon in the abaxial epidermis of leaf surface.