Cynthia Cavalcanti de Albuquerque

Antimicrobial action of the essential oil of Lippia gracilis Schauer

Avaliou-se a atividade antimicrobiana do oleo essencial (OE) de Lippia gracilis Schauer sobre fungos contaminantes de laboratorios de cultura de tecidos vegetais e bacterias endofiticas de heliconias. Discos de micelio dos fungos Geotrichum candidum; Trichoderma viride; Torula herbarum; Paecillomyces sp.; Aspergillus nidulans; Fusicoccum sp.; A. flavus; P. aeruginens; Curvularia lunata e A. niger, foram inoculados em meio BDA com oleo (0; 420; 440; 460; 480 e 500 µL L-1). O percentual de inibicao em 420 µL L-1 foi de 100% para todos os fungos exceto paraC. lunata and A. niger, o qual foi de 95.58% and 89.40% respectivamente. Em outro experimento, suspensao das especies Salmonela choleraceuis-diarizonae, Enterobacter asburiae, Bacillus thuringiensis, B. pumilus, Klebsiella pneumoniae, E. hormaechei, Bacillus pumilus, B. cereus, B. pumilus foi individualmente adicionada ao meio NYDA, que foi vertido em placas de Petri e, apos solidificado, perfurado e preenchido com agua ou oleo (420 µL L-1). Avaliou-se o diâmetro do halo de inibicao. Avaliou-se tambem, a inibicao em meio liquido. K. pneumoniae foi a especie bacteriana menos sensivel e E. hormaechei foi a mais sensivel.

In vitro selection of salt tolerant 'Nanicão' banana buds.

This work aims to evaluate the effect of NaCl and to make selections of banana cv. Nanicao (AAA) in vitro. Buds were grown on MS medium with 2.5 mg L-1 BAP and supplemented with different NaCl concentrations (0; 20; 40; 60; 80; 100 and 120 mM), for 60 days (Phase I). Survivor buds were transferred to salt-free media and grown for 30 days (Phase II). Afterwards they were submitted to MS media containing 80 or 100 mM NaCl, during 90 days (Phase III). One hundred buds were selected from the last phase and then, placed on NaCl-free medium supplemented with 0.5 mg L-1 NAA and 1.0 mg L-1 BAP for rooting. All buds died when submitted to 120 mM NaCl. Plant regeneration was highly inhibited by all NaCl concentrations. On the other hand, concentrations from 20 to 80 mM NaCl increased bud number and length. Buds were selected from treatments with 80 and 100 mM NaCl, and 80 plants were regenerated in media without NaCl. Rooting was not affected by saline pre-treatment.

Cultivo in vitro de ápices caulinares de abacaxizeiro para limpeza clonal em relação à fusariose

The object of this study was to find a nutricional means for the cultivation of the shoot tips of Perola pineapples, in order to free them of infections caused by Fusarium subglutinas. The first step was to remove healthy shoot tips from healthy crowns under aseptic conditions and inoculate nine different cultivation media with or whithout traces of BAP, GA3 and AIA. The levels of necrosis in the plants were studied after 30,45 and 60 days. Selected shoot tips removed from the plants contaminated with F. subglutinans were inoculated to check their viability as pathogen-free clones. The results revealed the influence of the cultivation media in the regeneration of plants and the viability of clonal cleansing of infected plants. It was also noted that 100% of the regenerated plants remained pathogen-free.

Early somatic embryogenesis in Heliconia chartacea Lane ex Barreiros cv. Sexy Pink ovary section explants

Este trabalho teve como objetivo avaliar a resposta de seccoes transversais de ovarios e o desenvolvimento de calos embriogenicos. O experimento constou de dois ensaios. No primeiro avaliou-se combinacoes entre AIA (0; 5.71; 8.56; 11.42; 14.27μM) e 2,4-D (0; 13.57; 18.10; 22.62μM) e no segundo avaliou-se as concentracoes de 2,4-D supracitadas, combinadas com concentracoes de BA (0; 4.43; 6.65; 8.87; 11.09μM). Os calos formados foram avaliados quanto a presenca de estruturas embriogenicas utilizando-se estereomicroscopio, microscopio eletronico de varredura, alem de analises citoquimicas e histologicas. Combinacoes entre 2,4-D e AIA induziram a formacao de calos friaveis com setores pro-embriogenicos, refletindo a aquisicao de competencia morfogenetica. Posteriormente foi observada a expressao do programa embriogenico quando massas pro-embriogencias desenvolveram-se formando embrioes somaticos. Esses resultados apresentam uma alternativa para a utilizacao de um tipo de explante que possibilita o cultivo in vitro de heliconia sem o desenvolvimento de bacterias endofiticas.

Caracterização isoenzimática de clones de bananeira nanicão submetidos à salinidade

O presente trabalho teve o objetivo de identificar possiveis variacoes isoenzimaticas em plantas de bananeira, provenientes de gemas da cultivar nanicao, submetidas a pressao de selecao in vitro, com 80 e 100 mol m-3 de NaCl. Apos aclimatadas, as plantas foram transferidas para solo com diferentes niveis de salinidade do extrato de saturacao do solo (CEe de 0,2, 7,0 e 14,0 dS m-1) e cultivadas, durante 30 dias, em casa-de-vegetacao. Em solo com CEe de 14,0 dS m-1 as plantas nao resistiram a salinidade. Dos sistemas isoenzimaticos analisados, apenas o sistema peroxidase apresentou atividade em todas as amostras de tecido foliar analisadas. As plantas regeneradas a partir de gemas submetidas ao estresse salino in vitro, apresentaram bandas anodicas e catodicas nos tratamentos com 0,2 e 7,0 dS m-1, enquanto as plantas provenientes de gemas nao tratadas em meio salino, apresentaram apenas bandas catodicas. Alteracoes em numero e intensidade de bandas isoenzimaticas podem ser decorrentes de variacoes somaclonais induzidas pelo estresse salino imposto durante o cultivo in vitro.

Effects of the essential oil of Lippia gracilis Schauer on caulinary shoots of heliconia cultivated in vitro

The effects of thymol and carvacrol and the essential oil of Lippia gracilis on caulinary shoots of heliconia were evaluated. After disinfection, the shoots were inoculated into MS medium and subjected to the treatments with 420 µL L-1 of essential oil (EO) of L. gracilis; 420 µL L-1 of thymol; 420 µL L-1 of carvacrol; 210 µL L-1 of thymol and 210 µL L-1 of carvacrol. The control treatment consisted of the MS medium without any phytoregulators. The main components of EO from L. gracilis are carvacrol, ρ-cimene, and thymol. Seven days after the initiation of the experiments, 36.3% of the control treatment shoots were necrotized, but 90% of the caulinary shoots exposed to EO, thymol, or carvacrol appeared necrotized. Transmission electron microscopy of the shoots revealed that the treatment with EO, thymol, or carvacrol caused the destruction of the plasma cell membranes, and the cell organelles and the nucleus were hardly evident. The EO and its main constituent were toxic to caulinary shoots of heliconia.

Extrato etanólico de Senna alata no controle de Fusarium oxysporum, causador da murcha-de-fusarium do meloeiro

Fusarium wilt, caused by Fusarium oxysporum fungi has become an important melon disease, due to great losses in the production areas in Brazil and in the world. Therefore, the objective of the present work was to evaluate efficacy of ethanolic extracts of Senna alata parts in the control of F. oxysporum micelial growth, isolated of melon plants. The experimental design was entirely randomized distributed in factorial scheme 4 x 6 + 1, being the first factor parts of the plant (stalk, leaf, root, and green bean), and as second, six concentrations (0.25; 0.50, 50, 75, 250, 500 µg mL-1), plus the control, with four repetitions per treatment. The variables evaluated were: rate of mycelial growth, inhibition of the mycelial growth (IGM) and area under the curve of the mycelia growth. Ethanolic extracts of all Senna alata parts were efficient in control of F. oxysporum. Extracts of root and string bean were most efficient in inhibiting the mycelial growth of F. oxysporum, in 500 µg mL-1 concentration.

Indução de embriões somáticos a partir de embriões zigóticos de Heliconia bihai (L.) L. cv. Lobster Claw Two

Somatic embryogenesis from zygotic embryos of Heloconia bihai (L.) L. cv. Lobster Claw Two Tropical flowers have contributed to the growth of the cut flower market in Brazil, especially plants of the genus Heliconia. Heliconias are usually propagated vegetatively, although this method can spread diseases and in the near future may severely comprise commercial flower production. In vitro cultivation represents an important potential alternative for guaranteeing the production of high-quality heliconia planting stocks. However , the micropropagation of these plants using stalk apices faces severe problems of endophytic contamination, making it difficult the supply of enough explants. Therefore, alternative techniques for the in vitro production of planting stock were investigated using other explant tissues to induce somatic embryogenesis. Zygotic embryos from immature and mature fruits of H. bihai (L.) L. cv. Lobster Claw Two were cultured in combinations of IAA (0; 5.70, e 11.41 µm L -1 ) and 2,4-D (0; 22.62; 45.24; 67.86 e 90.48 µm L -1 ) to induce somatic embryos during 90 days of culture. Histological analyses showed that somatic embryos were formed only with zygotic embryos derived from mature fruits cultivated in the absence of growth

In Vitro Propagation of Heliconia bihai (L.) L. from Zygotic Embryos

The internal morphology of embryos from immature and mature fruits of Heliconia bihai (L.) L. cv. Lobster Claw Two was examined. Embryos were inoculated into MS media (full MS and ½ MS) and GA3 (0, 2.5 and 5 mg L-1) with either sucrose or glucose. These plantlets were then replicated and transferred to MS medium (full MS or ½ MS) with 0 or 2.5 mg L-1 BAP and their multiplication was evaluated 30 and 45 days after inoculation. The genetic variability of the multiplied plants was estimated using isoenzyme analyses. The internal morphology of the mature embryos revealed their tissues to be in more advanced stages of differentiation than immature embryos. In the conversion phase, 85% of the inoculated embryos developed into plants in the ½ MS medium with sucrose, in contrast to only 41% of the embryos that were cultivated with glucose. In the multiplication phase, plants cultivated in ½ MS medium with 2.5 mg L-1 BAP demonstrated more buds. Isoenzyme analyses showed pattern changes in terms of the color intensity and the migration of some of the bands. These results may be associated with differences in the ages of the mother plants and of the plantlets obtained in vitro.

CRESCIMENTO DA CULTIVAR DE MILHO AL-BANDEIRANTES SOB CONDIÇÕES DE ESTRESSE SALINO

O Brasil é um grande produtor de milho, no entanto, devido à salinização dos solos, muitas áreas não são exploradas com esta cultura, pois o milho é considerado moderadamente sensível à salinidade, sofrendo alterações fisiológicas e redução progressiva do crescimento em áreas com o solo salinizado, comprometendo de forma significativa sua produtividade (Izzo et al., 1991). Este é um dos principais problemas da produtividade agrícola em vários países, sendo que os altos níveis de concentrações de sais no solo ocorrem mais intensamente em regiões áridas e semiáridas, como no Nordeste Brasileiro, que dependem da irrigação e não possuem uma drenagem eficiente, aliado ao uso de água de má qualidade (Oliveira et al., 2007). Este trabalho teve por objetivo avaliar o crescimento de plantas de milho da cultivar Al-bandeirantes submetidas à salinidade com NaCl e verificar possíveis características de resistência desta cultivar ao estresse salino.