ABSTRACT
Synthetic silver nanoparticles (AgNPs) are being extensively used in our daily lives; however, they may also pose a risk to public health and environment. Nowadays, biological AgNPs are considered an excellent alternative, since their synthesis occurs by a green technology of low cost and easy scaling. However, studies with these biological nanomaterials (NM) are still limited. Thus, a more careful assessment of their industrial application, economic feasibility and ecotoxicological impacts is crucial. The aim of this study was to investigate the effects of different concentrations of mangrove fungus Aspergillus tubingensis AgNPs on the aerobic heterotrophs soil microorganisms, rice seeds (Oryza sativa) and zebrafish (Danio rerio). Biogenic AgNPs were less harmful for soil microbiota compared to AgNO3. On rice seeds, the AgNPs displayed a dose-dependent inhibitory effect on germination and their subsequent growth and development. The percentage of inhibition of rice seed germination was 30, 69 and 80% for 0.01, 0.1 and 0.5 mM AgNPs, respectively. After 24h of AgNPs exposition at a limit concentration of 0.2 mM, it did not induce mortality of the zebrafish D. rerio. Overall, A. tubingensis AgNPs can be considered as a suitable alternative to synthetic nanoparticles.
ABSTRACT
En el Nuevo Mundo el género iPiper (Piperaceae) comprende al menos 500 especies en las que muchos compuestos biológicamente activos fueron identificados; es por ello que el estudio sobre la química y biosíntesis de los miembros de este género son de gran interés, donde el cultivo de tejidos in vitro juega un rol fundamental. El propósito de este trabajo fue desarrollar varios sistemas de cultivo in vitro, en diferentes especies de Piper, con la finalidad de propagarlas clonalmente y regenerarlas por organogénesis directa para el establecimiento de plantas en campo, y la conservación y transferencia internacional de germoplasma. La germinación de semillas alcanzó aproximadamente entre el 20 y el 99% después de 4 semanas de cultivo. La micropropagación fue realizada en medio de cultivo MS suplementado con sacarosa 3%, AIA 0,02 mg L-1 y AG3 0,02 mg L-1. El potencial morfogenético de explantes de raíz, peciolo, hoja, nudo y entrenudo fue investigado con la finalidad de desarrollar un protocolo confiable de regeneración de plantas. La conservación e intercambio internacional de germoplasma in vitro también fue realizado, entre Perú, Brasil y Ecuador.
In the New World the genus Piper (Piperaceae) contains at least 500 species in which many biologically active compounds were identified; is why the study of the chemistry and biosynthesis in members of this genus are of interest, and here techniques in vitro tissue culture plays a fundamental role. The aim of this work was to establish several in vitro culture systems in different Piper species in order to propagate clonally and regenerate by direct organogenesis for the establishment the field plants, the conservation and international germoplasm exchange. The seed germination achieved approximately 20 - 99% after 4 weeks of culture. The micropropagation was performed on MS culture medium supplemented with sucrose (3%), IAA (0,02 mg L-1) and GA3 (0,02 mg L-1). Callus induction and morphogenetic potential of root, petiole, leaf, node and internode explants was investigated to develop a reliable plant regeneration protocol. The in vitro germplasm conservation and international germplasm exchange also was realized, between Perú, Brazil and Ecuador.
Subject(s)
Organogenesis , Piper , GrowthABSTRACT
Informações referentes à utilização de reguladores de crescimento em crotalária ainda são escassas, notadamente sobre a qualidade fisiológica de sementes e o crescimento de plântulas. Nesse aspecto, o conhecimento do produto e da dose de aplicação se destaca como fatores relevantes na produção de sementes de boa qualidade. Este trabalho objetivou avaliar o efeito da aplicação foliar de reguladores de crescimento (cloreto de mepiquat, etil-trinexapac e paclobutrazol) em diferentes doses (0; 75; 150; 225 e 300 g ha-1), sobre a qualidade fisiológica de sementes e o crescimento de plântulas de Crotalaria juncea cultivada em sistema plantio direto. Os tratamentos foram dispostos em delineamento experimental de blocos ao acaso em esquema fatorial 3 x 5 (reguladores x doses de aplicação), com quatro repetições. Os resultados foram submetidos à análise de variância, com os reguladores de crescimento comparados pelo teste de Tukey e as doses por regressão polinomial. Não se recomenda a aplicação de cloreto de mepiquat na cultura da crotalária por reduzir o potencial de germinação das sementes e a biomassa fresca de plântula. O etil-trinexapac deve ser aplicado na dose de 300 g ha-1, com base na redução do grau de umidade e na condutividade elétrica das sementes, maior comprimento total de plântula e biomassa fresca de plântula. O paclobutrazol deve ser aplicado na dose de 75 g ha-1 , considerando o potencial e velocidade de germinação das sementes.
Information regarding the use of growth regulators in sunn hemp is still scarce, especially on the physiologic quality of seeds and growth seedlings. In this aspect, product knowledge and application rate stands out as relevant factors in production of quality seeds. This work aimed to evaluated the effect of the foliar application of growth regulators (mepiquat chloride, etil-trinexapac and paclobutrazol) in different rates (0; 75; 150; 225 and 300 g ha-1), on the physiological quality of seeds and growth seedlings of Crotalaria juncea cultivated in no-tillage system. The treatments were disposed in randomized complete block design in factorial scheme 3 x 5 (regulators x rates of application), with four replications. The results were submitted to the variance analysis, with the growth regulators compared by Tukey test and the rates for polynomial regression. Not if recommended the application of mepiquat chloride in sunn hemp culture by reducing the potential of seeds germination and dry biomass of seedlings. The etil-trinexapac must be applied in rate of 300 g ha-1, based on the reduction of moisture content and the electrical conductivity of seeds, the greater total length of seedlings and dry biomass of seedlings. The paclobutrazol must be applied in rate of 75 g ha-1, considering the potential and speed of seeds germination.
Subject(s)
Plant Growth Regulators , Seeds , Germination , SeedlingsABSTRACT
The objective of this research was study the effects of kinetin and gibberellins on Poncirus trifoliata x Citrus paradisi seed germination. The medium for seed germination was filter paper moisted with distilled water. The seeds were removed from ripe fruits, washed, dried and placed in refrigerator at 4-5C. After that, the seeds were treated with growth regulators during 24 hours. The treatments were H2O; 50 mg/l de GA3; 250 mg/l de GA3, 50 mg/l de GA4 + GA7 + phenylmethylaminepurine; 100 mg/l de GA4 + GA7 + phenylmethylaminepurine; 20 mg/l of phenylmethylaminepurine; 40 mg/l of phenylmethylaminepurine. The evaluations were accomplished every two days starting 10 days after seeding. The GA3 50 or 250 mg/l proved to be most beneficial in enhancing seed germination.
Foram estudados os efeitos de giberelinas e citocininas, na germinação de sementes de citrumelo "Swingle" (Poncirus trifoliata x Citrus paradisi). As sementes foram colocadas no germinador em gerbox contendo papel de filtro umedecido com água destilada. As sementes, retiradas de frutos maduros, foram lavadas, secadas à sombra e armazenadas em câmara fria; logo após, foram tratadas com os fitorreguladores por 24 horas, definindo os seguintes tratamentos: H2O; 50 mg/l de GA3; 250 mg/l de GA3, 50 mg/l de GA4 + GA7 + fenilmetilaminopurina; 100 mg/l de GA4 + GA7 + fenilmetilaminopurina; 20 mg/l de fenilmetilaminopurina e 40 mg/l de fenilmetilaminopurina. As avaliações foram realizadas depois de 10 dias de semeadura, num intervalo de 2 dias entre elas. Através da análise estatística dos resultados obtidos, foi possível concluir que, no tratamento com 50 ou 250 mg/l de GA3, houve a maior porcentagem de germinação de sementes, em menor tempo.
ABSTRACT
The objective of this research was study the effects of kinetin and gibberellins on Poncirus trifoliata x Citrus paradisi seed germination. The medium for seed germination was filter paper moisted with distilled water. The seeds were removed from ripe fruits, washed, dried and placed in refrigerator at 4-5C. After that, the seeds were treated with growth regulators during 24 hours. The treatments were H2O; 50 mg/l de GA3; 250 mg/l de GA3, 50 mg/l de GA4 + GA7 + phenylmethylaminepurine; 100 mg/l de GA4 + GA7 + phenylmethylaminepurine; 20 mg/l of phenylmethylaminepurine; 40 mg/l of phenylmethylaminepurine. The evaluations were accomplished every two days starting 10 days after seeding. The GA3 50 or 250 mg/l proved to be most beneficial in enhancing seed germination.
Foram estudados os efeitos de giberelinas e citocininas, na germinação de sementes de citrumelo "Swingle" (Poncirus trifoliata x Citrus paradisi). As sementes foram colocadas no germinador em gerbox contendo papel de filtro umedecido com água destilada. As sementes, retiradas de frutos maduros, foram lavadas, secadas à sombra e armazenadas em câmara fria; logo após, foram tratadas com os fitorreguladores por 24 horas, definindo os seguintes tratamentos: H2O; 50 mg/l de GA3; 250 mg/l de GA3, 50 mg/l de GA4 + GA7 + fenilmetilaminopurina; 100 mg/l de GA4 + GA7 + fenilmetilaminopurina; 20 mg/l de fenilmetilaminopurina e 40 mg/l de fenilmetilaminopurina. As avaliações foram realizadas depois de 10 dias de semeadura, num intervalo de 2 dias entre elas. Através da análise estatística dos resultados obtidos, foi possível concluir que, no tratamento com 50 ou 250 mg/l de GA3, houve a maior porcentagem de germinação de sementes, em menor tempo.