Lilia Willadino

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.

Polyamine and free amino acid variations in NaCL-treated embryogenic maize callus from sensitive and resistant cultivars

Summary The effect of different NaCl concentrations on maize embryogenic calluses derived from immature embryo cultures of a) the salt-sensitive inbred line W64Ao2, b) the resistant hybrid Arizona 8601 and c) the 0.4% NaCl pre-adapted W64Ao2 (WpA) calluses was studied. The effect of salt stress on growth as well as on polyamine (putrescine, spermidine and spermine) and amino acid contents of the treated calluses was determined. Enzymatic activities of the polyamine biosynthetic enzymes arginine and ornithine decarboxylase were also analyzed. A significant decrease in the growth of calluses in relation to increased salt concentrations and to the tolerance of the callus was observed. Embryogenic Arizona calluses showed the lowest growth inhibition and W64Ao2 calluses the highest inhibition after 60 days of culture in saline medium. WpA calluses showed an intermediate response. At high-salt concentrations (1.2–2.0%), calluses showed a significant increase in total polyamine content, especially caused by a rise in putrescine. This increase was proportionally higher for Arizona and WpA than for W64 calluses. Whereas the spermidine content of Arizona calluses was augmented with salt, a spermidine decrease was observed for W64 from 0.8 % NaCl. Arginine decarboxylase activity increased from 1.2 to 2.0 % NaCl for Arizona calluses, while in W64 calluses this increase was lower than in Arizona up to 2.0 %. With respect to free amino acid contents, the levels of free proline, which represent 50 % of the total free amino acid content, decreased with increasing salt in the medium. The highest amino acid increases were observed for arginine, alanine, glutamine, glutamic acid and y-aminobutyric acid. Arginine decarboxylase activity showed significant increments in relation to salt stress, which may be related to putrescine and some amino acid variations. Relationships between all the analyzed parameters and the polyamine synthesis and degradation processes under stress conditions are discussed.

Stock indexing and Potato virus Y elimination from potato plants cultivated in vitro

Potato cultivars (Solanum tuberosum L.) have shown degeneration or run out caused by viruses after several cycles of propagation using seed tubers from commercial fields. This work reports the occurrence of single and mixed infections of four potato viruses in Paraiba-Brazil and presents a method for Potato virus Y (PVY) elimination, by using thermo-and chemotherapies. Plants of potato cv. Baraka were tested by direct antigen coating ELISA. Antisera against PVY, Potato virus X (PVX), Potato virus S (PVS), and Potato leafroll virus (PLRV) were used. Materials with positive reaction to PVY were treated for virus elimination. Single node cuttings (1.0 cm length) were excised and inoculated in Murashige & Skoog (MS) medium, supplemented with 1.0 mg L-1 of kinetin, 0.001 mg L-1 of naphthalene acetic acid (NAA) and 0.1 mg L-1 of gibberellic acid (GA3). The thermotherapy at approximately 37oC, during 30 and 40 days, resulted in 20.0 and 37.5% PVY elimination, respectively. Chemotherapy was undertaken with Ribavirin (RBV), 5-Azacytidine (AZA), and 3-Deazauridine (DZD). The RBV showed the highest rate of virus eradication, with 55.5% virus-free plants. Simultaneous thermo and chemotherapy had higher efficiency for the elimination of PVY, reaching rates of healthy plants of 83.3% with RBV, 70.0% with AZA, and 50.0% with DZD.

Geração e desintoxicação enzimática de espécies reativas de oxigênio em plantas

The biotic and abiotic stress conditions imposed on plants induces overproduction of reactive oxygen species (ROS), which can cause damage to cellular structures and even lead to the death of the plant. The biochemical and physiological responses of higher plants to oxidative stress includes an efficient antioxidant defense system, which involves the activity of the enzymes superoxide dismutase, catalase, ascorbate peroxidase, peroxiredoxines, among others, in addition to non-enzymatic metabolites, which, together, work on eliminating the ROS and in reducing oxidative damage. This review will address the main production sites of ROS and the action of some enzymes of antioxidative defense system in plants.

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.

Efeito do estresse salino em genótipos tetraplóides de bananeira

This study evaluated 12 banana genotypes with respect to salt tolerance during initial growth, the most sensitive stage of the phenological cycle. Plants were grown for 21 days under 100 mM NaCl or under a control treatment without NaCl. Biometrical parameters and mineral contents in plant tissue were evaluated. Six genotypes (Calipso, FHIA-02, PA 42-44, Bucaneiro, FHIA-03 and PV 42-142) out of 12 considered in this study showed toxicity symptoms induced by saline treatment. The PA 42-44 genotype was pointed out as the most sensitive one because it showed the highest Na+ contents in both leaf blade and roots and rizome, besides a 18.5% reduction of dry matter production. The high Na+ contents found for PA 42-44 tissues suggest a low efficacy to extrude and to prevent the Na+ translocation to leaf blade. On the other hand, the Preciosa genotype showed both the lowest Na+ contents and the smallest reduction for dry matter production (0.2%) as well as a low Na+/K+ ratio indicating a salt tolerance strategy by Na+ extrusion.

Callus induction and plant regeneration of tomato (Lycopersicon esculentum cv. IPA 5) via anther culture

Diferentes combinacoes de reguladores de crescimento foram testadas na producao de calos a partir do cultivo de anteras de tomate cultivar IPA 5. Calos foram induzidos no meio suplementado com 1,0mgL-1 de acido giberelico (GA3) + 0,05mgL-1 de a-acido naftalenoacetico (ANA) + 0,1mgL-1 de 6-benzilaminopurina (BAP), ou com 1,0mgL-1 de BAP + 1,0mgL-1 de ANA. O meio contendo 1,0mgL-1 de BAP e 1,0mgL-1 de ANA produziu a maior frequencia de calos e promoveu a regeneracao de plantas atraves de organogenese indireta, quando os calos foram transferidos para 0,01mgL-1 de BAP e 0,001mgL-1 de ANA. As plantas regeneradas apresentaram celulas tetraploides e, raramente, celulas diploides. Estas plantas tetraploides podem servir como fonte para posterior obtencao de linhagens trissomicas, para serem utilizadas em estudos de localizacao genica e em analises de compostos proteicos.

Efeito do estresse salino e da prolina exógena em calos de milho

This work aimed at evaluating the effect of different NaCl concentrations (0, 68, 137 and 205 mM) in two maize (Zea mays L.) genotypes (W64Ao2 and Arizona 8601) callus cultures in N6 medium, supplemented or not with 6.0 mM proline. Treatments consisted of the combinations of the four NaCl levels with the two-proline levels under 4x2 factorial. Treatments were maintained for 60 days with subcultures at 20 days each. Relative growth rate, endogenous free putrescine, spermine, spermidine, proline and others amino acids were evaluated at the end of the experimental period. Proline addition improved callus growth in both genotypes in the control treatment and reduced deleterious effects in the highest salt level (250mM NaCl). W64Ao2 callus growth rate was higher than in the Arizona 8601 probably due, in part, to the higher proline accumulation and the maintenance of polyamine metabolism in those calluses.

Water deficit and salt stress diagnosis through LED induced chlorophyll fluorescence analysis in Jatropha curcas L. oil plants for biodiesel

Light-emitting-diode induced chlorophyll fluorescence analysis is employed to investigate the effect of water and salt stress upon the growth process of physicnut(jatropha curcas) grain oil plants for biofuel. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit) for a period of time of 30 days. The chlorophyll fluorescence(ChlF) ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the level of stress experienced by the jatropha plants. The ChlF technique data indicated that salinity plays a minor role in the chlorophyll concentration of leaves tissues for NaCl concentrations in the 25 to 200 mM range, and results agreed quite well with those obtained using conventional destructive spectrophotometric methods. Nevertheless, for higher NaCl concentrations a noticeable decrease in the Chl content was observed. The Chl fluorescence ratio analysis also permitted detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed sample in the first 10 days of the experiment when one compared control and nonwatered samples. The results suggest that the technique may potentially be applied as an early-warning indicator of stress caused by water deficit.

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.