Reguladores vegetais e teores endógenos de poliaminas durante o desenvolvimento de taro cultivado in vitro

Neste trabalho foi investigada a assepsia para obtenção de explantes oriundos de tubérculos e a ação das poliaminas espermidina e espermina exógenas associadas aos reguladores vegetais AIA e BA no desenvolvimento, na tuberização in vitro e nos níveis endógenos de putrescina (Put), espermidina (Spd) e espermina (Spm) de taro (Colocasia esculenta). Plantas crescidas em meio contendo espermidina e espermina mostraram tuberização e a associação dessas poliaminas com AIA e BA induziu aumento do número de brotações. Para o estímulo da rizogênese, não foi necessário o uso de reguladores vegetais. Altos teores de putrescina foram encontrados durante a emissão de brotações, enquanto que altos teores de espermidina foram observados durante a formação de rizomas in vitro.

Ação de produtos químicos in vitro e in vivo sobre Clavibacter michiganensis subsp. michiganensis, agente causal do cancro bacteriano do tomateiro

O presente trabalho teve como objetivo avaliar a sensibilidade in vitro e in vivo de um isolado de Clavibacter michiganensis subsp. michiganensis (Cmm) aos produtos cloridrato de kasugamicina, fulusulfamide e oxitetraciclina. Para o teste in vitro, foram avaliados os halos de inibição formados ao redor de discos de papel de filtro umedecidos com os produtos, nas concentrações de 0, 1, 10, 100 e 1000 mig mL-1, 24 h após a instalação do ensaio. Quanto à avaliação dos produtos in vivo, dois ensaios foram instalados sob condições de casa-de-vegetação, com plantas de tomateiro cultivar Ângela Hiper, através da inoculação das plantas por dois métodos: pulverização foliar e ferimento no caule. Nos dois ensaios, as plantas foram pulverizadas com os produtos cloridrato de kasugamicina a 0,06 mL L-1, fulusulfamide a 0,025, 0,05 e 0,075 mL L-1 e oxitetraciclina a 0,40 g L-1, duas vezes antes e duas vezes após a inoculação, em intervalos médios de 5-7 dias. Foram avaliados a incidência de folíolos doentes (inoculação foliar) e a severidade dos sintomas nas plantas inoculadas por ferimento no caule. Verificou-se que o isolado de Cmm foi sensível in vitro ao cloridrato de kasugamicina, ao fulusulfamide e à oxitetraciclina, respectivamente a partir das concentrações de 1000, 100 e 10 mig mL-1. Com relação aos ensaios in vivo, apenas oxitetraciclina propiciou menor incidência de folíolos doentes nas plantas inoculadas através de pulverização foliar; nenhum produto teve êxito em controlar a doença nas plantas inoculadas por ferimento no caule. O fulusulfamide, em todas as concentrações, foi fitotóxico aos folíolos das plantas de tomateiro.

Multiplicação in vitro de amoreira-preta cultivar Brazos

A micropropagação da amoreira-preta pode gerar plantas livres de vírus e em curto espaço de tempo. Com o objetivo de aprimorar técnicas de micropropagação de amoreira-preta cultivar Brazos (Rubus idaeus L.), segmentos nodais, oriundos de plântulas preestabelecidas in vitro foram excisados e inoculados em meio WPM (0, 50, 100, 150 e 200%), suplementado com diferentes concentrações de BAP (0; 0,5; 1,0; 2,0 e 4,0 mg L-1). Após a inoculação, os explantes foram transferidos para sala de crescimento a 27±1ºC, irradiância de 35 mmol m² s¹ e fotoperíodo de 16 horas, onde permaneceram por 60 dias. O delineamento experimental utilizado foi inteiramente casualizado, utilizando-se de quatro repetições com quatro explantes cada. Maior número de brotos foi proporcionado com 1,0 mg L-1 de BAP associado a 100% de meio WPM e maior comprimento médio dos brotos após 60 dias foi verificado em 1,0 mg L-1 de BAP associado a 200% de meio WPM. Maior peso de matéria seca da parte aérea foi obtido em meio WPM 200% acrescido de 0,5 mg L-1 de BAP.

Anatomia quantitativa e degradação in vitro de tecidos em cultivares de capim-elefante (Pennisetum purpureum Schumach.)

Neste trabalho quantificaram-se as principais alterações histológicas ocorridas em cultivares de capim-elefante (Pennisetumpurpureum Schumach.), em três estádios de desenvolvimento. A degradação dos tecidos foi avaliada após incubação em líquido ruminal de bovinos. As porcentagens de tecidos presentes em colmo, quilha, limbo e bainha foliares foram determinadas. A quilha e o colmo apresentaram maior proporção de tecido lignificado, enquanto o limbo foliar, maior quantidade de tecido epidérmico e tecido vascular não-lignificado. O tecido parenquimático foi encontrado em menor proporção na bainha foliar, principalmente pela presença do aerênquima, a partir da segunda coleta. A proporção de tecido lignificado aumentou com a maturidade do vegetal, sendo mais acentuado em colmos e limbos. Entre as principais alterações, destaca-se a grande área de degradação encontrada na bainha foliar, mesmo com o envelhecimento dos tecidos. Isto foi associado à presença do aerênquima encontrado nos estádios de desenvolvimento mais avançados. Os estômatos favoreceram a penetração dos microorganismos nos tecidos mais internos da folha (mesofilo). O espessamento e a lignificação da parede celular ocorreram com o envelhecimento das plantas, acompanhado de redução na área de degradação dos tecidos.

Variação na estrutura da vegetação de duas cultivares de Panicum maximum jacq. (colonião e tabiatã) submetidas a diferentes tipos de manejo. Composição em proteína bruta e digestibilidade In vitro da matéria seca

This work was carried out at FCAV-UNESP, Campus of Jaboticabal, Brazil, to study the effects of nitrogen fertilization (0 and 50 kg N/ha/cut), three sucessive periods of growth (December 21st 1987, January 25th 1988 and February 29th 1988)) and three cutting ages (28, 35 and 42 days) on composition in crude protein and in vitro dry matter digestibility of two cultivars of Panicum maximum Jacq. i.e., Coloniao and Tobiata. Plants were harvested in five vertical layers above soil level (0-20, 20-40, 40-60, 60-80 and over 80 cm). The samples were divided in: green leaves, green stems and dry material. Generally, values of in vitro dry matter digestibility and the levels of crude protein of both cultivars were greater in the higher layers of the vegetation, with a decrease, however, for the other layers and more advanced phases of plants development, mainly with no N fertilization.

Efeito do extrato aquoso de sete-sangrias [Cuphea mesostemon (Koehne) Lourt] sobre o fluxo de água, medido em bexiga urinária de sapo in vitro

The Cuphea mesostemon specie, known as sete-sangrias, is widely used as a diuretic substance in popular medicine. As the toad urinary bladder is an epithelium analogous to the distal nephron of mammals, it is used in order to study the transport water and electrolytes in many laboratories. This preparation permits excellent observation in water flow, from the urinary bladder lumen to the external side or the serosal one (water re-absorption), by means of gravimetrical measures. In the present work the hydrosmotic effect of aqueous extract (AE) of sete-sangrias leaf was studied. A 20% solution was added to the serosal side (S) of the bladder preparation, and the water flow was measured every 15 minutes after that. The results showed that 4mL of AE in the S side, increased the JH20 in a significant manner (p<0,05). This effect had a dose - response shape, with the volumes of 0,2mL, 0,4mL and 0,8mL of AE in the S bath. The hydro-osmotic effect of the anti-diuretic hormone (ADH) was studied as well and a significant stimulation (p<0,05) in the JH2O was observed with the magnitude of 150%. The AE effect was similar to the ADH one, and was not antagonized by this hormone. We concluded that Cuphea possesses an anti-diuretic activity similar to that presented by ADH, in toad urinary bladder, in vitro.

Atividade da enzima bromelina emplantas de abacaxi (Ananas comosus L. Merril), sob condições de salinidade in vitro

The objectives of this work were to characterize pineapple plants (Ananas comosus L. Merril) cv. Smooth Cayenne, cultured in vitro, in saline medium, in relation to bromelian activity, identifying the parts of the plant with the highest bromelian activity. Also under aim was the study of the influence of saline stress on the enzyme activity. Axillary buds of pineapple were cultivated in vitro in MS medium, supplemented with 2 mg.L-1 BAP and 1 mg.L-1 NAA. The levels of salinity tested were: 0.57 g.L-1 NaCl, 1.15 g.L-1 NaCl, and 2.30 g.L-1 NaCl. Bromelian activity was evaluated in the development of buds, shoots, and roots. The results showed that bromelian activity was higher in buds at the highest salt concentration at 15 days. Cultured shoots showed bromelian activity decreasing in the saline treatments in all the collection, up to 60 days in culture. The roots showed higher bromelian activity in the roots in saline medium.

Avaliação de diferentes sistemas de cultivo in vitro para a micropropagação de Psychotria ipecacuanha (Brot.) Stokes

This work was carried out with Psychotria ipecacuanha, a Brazilian medicinal plant the roots of which contain emetine. The main objective was to develop a protocol for the micro-propagation of these species, by testing different culture techniques, the temporary immersion system, and the semi-solid and liquid media systems. In the semi-solid system, experiments were developed in flasks of two different sizes containing MS, B5, and WP media to which were added different growth regulators. Innoculum density was also evaluated. The liquid medium system consisted of MS medium supplemented with different growth regulators. For the temporary immersion system, the MS medium received an addition of 1.5mg/L BAP and 0.5mg/L GA3, and a reverse digital apparatus and vacuum pump were used. The liquid medium system with MS medium supplemented with 1.5mg/L BAP and 0.5mg/L GA3 presented the best results for shoot proliferation in a period of 30 days in culture (2.37 ± 0.32 shoots/explant). Cultures carried out for 90 days in the semi-solid system, using 8.5 × 5.5cm flasks and 3 explants per flask, developed 1.80 ± 0.20 shoots/explant, achieving 3.06 ± 0.51 cm of height adn presented superior survival ratio (96%). Explants cultured in temporary immersion system for 90 days showed 2.30 ± 1.10 shoots/explant achieving a growth of 2.08 ± 0.12 cm and 52% survival.

Enraizamento in vitro e aclimatização de mudas micropropagadas de Aloe vera L.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito de poliaminas exógenas no crescimento inical in vitro e nos teores de fenóis, poliaminas e atividade da peroxidase em Aloe vera (L.) Burm.

Lateral shoots of the Aloe vera (L.) Burm. cultivated in vitro, without addition vegetal regulators, for 90 days, were inoculated in MS culture-medium, containing or not spermine and/or spermidine. After 30 days of cultivation, the plants were submitted to biochemical analysis together with micropropagated plants - that were under in vitro cultivation for 90 days - (denominated as characterization), and matrix plants (in vivo). The levels of free polyamines, total phenols, total flavonoids, and the activity of peroxidase were evaluated in the biochemical analyses. The exogenous application of spermidine have promoted large number of shoots. Spermidine and spermine have promoted, when associated, an increase in the number of shoots as well as an increase of the contents of putrescine and and flavonoids. The putrescine has presented the most significant alterations, enabling to be utilized as marker of morphogenesis in the micropropagated Aloe vera. Tissues under active growth have presented high activity of peroxidase as well as those with greater rate of oxidation. In these tissues, there were noticed also higher contents of total flavonoids, indicating the need of antioxidative compounds. The action of polyamines jointly tseemed to be benefic for the shooting of micropropagated Aloe vera.

Carotenóides totais em Pothomorphe umbellata (L.) Miq. cultivadas in vitro

The aim of the present work was to compare the content of carotenoids between callus and regenerated plants of Pothomorphe umbellate. Germinated seeds (40 days old) were inoculated in different concentrations and combinations of BAP (benzylaminopurine) and NAA (naphthalene acetic acid) in order to stimulate the callus' production. After 60 days of culture, the callus containing some shoots were transferred to organogenesis medium (GA 3 0.1 mg L -1, BAP 0.5 mg L -1) for 40 days. Next, they were subcultivated in a medium for seedling growth (without regulators) for 40 days. Callus (collected after 60 days) and seedlings (collected after 140 days) were frozen in liquid nitrogen and kept under -80°C for future carotenoids' analysis. The highest concentration of carotenoids was found in plants cultivated in medium without regulators. The callus did not showed difference concerning the culture medium; however, they presented lower content of carotenoids in relation to plants.

Avaliação in vitro de diferentes métodos de análises de fungitoxicidade de óleos essenciais

Environmental problems caused by synthetic fungicides have increased the search for alternative methods of control of plant diseases. The objective was to evaluate the effect of essential oil of citronella grass, on the fungus Rhizoctonia solani, in different methods of in vitro fungitoxicity. We used a randomized design in a factorial design with four replications, where the factors were composed of four methods for assessing the in vitro fungitoxicity of the essential oil of citronella grass (essential oil diluted in Tween 80 (0.5%) and embedded in the culture medium PDA (potato dextrose agar) still melting, essential oil diluted in Tween 80 (0.5%) and distributed on the surface of the PDA; oil essential diluted in Tween 80 (0.5%) and distributed on filter paper attached to the inner surface of the lid of the Petri dish, pure essential oil and distributed on the surface of the culture medium, and control) and five evaluation periods (2, 4, 6, 8 and 10 days of incubation). Was used 0.25μL mL-1 of citronella oil in all treatments. Of the treatments evaluated the use of pure oil distributed on the surface of the culture medium was more effective in reducing the mycelial diameter in all evaluations. In this method the rate of mycelial growth was 9,02 mm day-1, reaching in last evaluation 79,77 mm.

Óleos essenciais: verificação da ação antimicrobiana in vitro, na água e sobre a microbiota da pele humana

Pós-graduação em Biologia Geral e Aplicada - IBB

Eficácia de ácidos húmicos e fúlvicos no controle de Meloidogyne incognita e Meloidogyne javanica in vitro e na cultura de cana-de-açúcar em vasos

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Ação moduladora do citral e eugenol em eventos genéticos em magrófagos murinos in vitro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)