Abstract The aim of this work was to evaluate the effect of five light qualities [fluorescent lamps (FL); white (WL), red (RL), blue (BL), or red/blue LEDs (RBL)] and two types of flask sealing (with or without porous membranes) in the in vitro germination and growth of two Capsicum frutescens cultivars (Espaguetinho and Cayenne). For this, two seeds were inoculated per flask (350 mL) containing 50 mL of MS medium with 100 mg L-1 myo-inositol, 30 g L-1 sucrose, 6.0 g L-1 agar, and pH 5.8 ± 0.1. The plants were kept under culture room conditions (16-h photoperiod, 25 ± 2°C and irradiance of 40 μmol m-2 s-1). The experiment was arranged in CRD, 2x5x2 factorial scheme (Cultivar X Light qualities X Sealing type). At 42 days, the following traits were evaluated: percentage of germination; root and shoot length; number of green leaves, senescent leaves and nodal segments; and fresh and dry weight. Plants grown under RL and BRL, showed greater number of green leaves, and longer shoots and roots. The use of porous membranes remarkably reduced the number of senescent leaves. Thus, the use of porous membranes, RL and BRL are recommended since they improve growth and development of pepper in vitro.

RESUMO O uso de pesticidas com alta toxicidade para controlar patógenos do solo, como Fusarium spp. e Sclerotinia sclerotiorum, tem gerado preocupação, devido aos impactos irreversíveis causados no meio ambiente, além de selecionar isolados resistentes. Dessa forma, os óleos essenciais surgem como uma alternativa eficiente no controle de doenças. Diante da problemática de controle de patógenos do solo e alto potencial antimicrobiano que os óleos essenciais possuem, este trabalho teve como objetivo avaliar o potencial fungicida de óleos essenciais no controle de Fusarium spp. e S. sclerotiorum, in vitro. Utilizou-se um delineamento inteiramente randomizado, esquema fatorial 2×4×8, com dois isolados (Fusarium spp. e S. sclerotiorum), quatro óleos essenciais (Aloysia citriodora, Cymbopogon winterianus, Lippia alba e Ocimum americanum) e oito concentrações de óleo essencial (0,0; 0,2; 0,4; 0,6; 0,8; 1,0; 1,2 e 1,4 ?L·mL-1), com dez repetições. Os óleos essenciais inibiram o crescimento micelial dos fungos em diferentes concentrações, sendo seu potencial justificado pela presença de compostos químicos antifúngicos. Os óleos essenciais de A. citriodora, C. winterianus, L. alba e O. americanum apresentam alto potencial fungicida, sendo alternativas viáveis para formulação de produtos comerciais, impulsionando a indústria de agrotóxicos.

ABSTRACT The use of highly toxic pesticides to control soil pathogens, such as Fusarium spp. and Sclerotinia sclerotiorum has generated concern, due to the irreversible impacts caused on the environment, in addition to selecting resistant isolates. In this way, essential oils appear as an efficient alternative in control of diseases. Facing the problem of soil pathogens control and high antimicrobial fungicide that essential oils present, this work aimed to evaluate the in vitro fungicidal potential of essential oils in control of Fusarium spp. and S. sclerotiorum. A completely randomized design, factorial scheme 2×4×8 was used, with two isolates (Fusarium spp. and S. sclerotiorum), four essential oils (Aloysia citriodora, Cymbopogon winterianus, Lippia alba and Ocimum americanum), eight essential oil concentrations (0.0; 0.2; 0.4; 0.6; 0.8; 1.0; 1.2 and 1.4 ?L·mL-1), and ten replicates. The essential oils inhibited mycelial growth of the fungi in different concentrations, being their potential justified by the presence of antifungal chemical compounds. Essential oils of A. citriodora, C. winterianus, L. alba and O. americanum present high fungicidal potential, being viable alternatives for formulation of commercial products, boosting the pesticides industry.

RESUMEN Los metabolitos secundarios son producidos por ciertas especies de plantas, y pueden influir en el desarrollo de algunas especies, debido a la acción de los efectos alelopáticos. Por lo tanto, el objetivo del trabajo fue evaluar el efecto alelopático del aceite esencial de Lippia alba en la germinación, emergencia y vigor de las plántulas de diferentes lotes de semillas de lechuga. El experimento se realizó en un diseño completamente al azar, en un esquema factorial 3x5, que consta de tres lotes de semillas del cultivar Grand Rapids® y cinco dosis de aceite esencial de L. alba (0; 0,25; 0,50; 0,75 y 1,00%) diluido en agua destilada y homogeneizado en Tween® 80. Se evaluó la germinación y el vigor de la semilla en el laboratorio (experimento I) y la emergencia en un ambiente protegido (experimento II). Los resultados obtenidos mostraron que hubo un efecto inhibitorio con una reducción significativa de la germinación, el vigor y la emergencia de la semilla cuando se añadió aceite esencial de L. alba a partir de concentraciones de 0.25%. El aceite esencial mostró potencial alelopático sobre diferentes lotes de semillas de lechuga, afectando la germinación, el vigor y la emergencia de las semillas.

ABSTRACT Secondary metabolites are produced by certain plant species and may influence the development of some species through the action of allelopathic effects. Thus, the objective of this study was to evaluate the allelopathic effect of Lippia alba essential oil on the germination, emergence and vigor of seedlings of different batches of lettuce seeds. This experiment was conducted in a completely randomized design with a 3x5 factorial scheme consisting of three batches of seeds of the cultivar Grand Rapids® and five doses of L. alba essential oil (0, 0.25, 0.50, 0.75 and 1.00%) diluted in distilled water and homogenized in Tween® 80. Seed germination and vigor, in the laboratory (experiment I), and emergence, in a protected environment (experiment II), were evaluated. The results demonstrated that there was an inhibitory effect with a significant reduction of germination, vigor and seed emergence when L. alba essential oil was added starting at concentrations of 0.25%. The essential oil showed allelopathic potential over different lettuce seed lots, affecting germination, vigor and seed emergence.

Resumo A fonte de luz na cultura de tecidos muitas vezes é um dos fatores pontuais para a adequação da produção de plantas, para isso, vêm se utilizando os diodos emissores de luz (LEDs) no intuito de aumentar o crescimento e desenvolvimento das plantas propagadas in vitro. O objetivo do trabalho foi avaliar a propagação in vitro de cultivares de Alpinia purpurata ‘Red Ginger’ e ‘Pink Ginger’ em duas diferentes fontes de luz (lâmpadas tubulares fluorescentes ou LED Branco). O experimento foi conduzido em delineamento inteiramente casualizado, esquema fatorial (2x2), totalizando quatro tratamentos com dez repetições, e a unidade experimental composta por um frasco contendo cinco explantes. Após 55 dias, foi possível observar que lâmpadas LED branco e a cultivar Red Ginger proporcionaram o maior número de brotos. Já para o número de folhas, a cultivar Red Ginger e lâmpadas LED branco proporcionaram resultados superiores. Para comprimento da parte aérea, a cultivar Red Ginger mantida sob lâmpadas fluorescentes foi superior, e a Pink Ginger apresentou superioridade quando cultivada sob luzes LED. Assim, mesmo com respostas diferenciadas entre genótipos, sugere-se o uso de lâmpadas LED branco na propagação in vitro das cultivares de Alpinia purpurata ‘Red Ginger’ e ‘Pink Ginger’.

Abstract The light source in tissue culture is often one of the punctual factors for the adequacy of plant production. For this, light emitting diodes (LEDs) have been used in order to increase the growth and development of the plants propagated in vitro. The objective was to evaluate the in vitro propagation of cultivars of Alpinia purpurata ‘Red Ginger’ and ‘Pink Ginger’ in two different light sources (fluorescent or LEDs tubes). The experiment was conducted in a completely randomized design, factorial scheme (2x2), totaling four treatments with ten replicates, and the experimental unit composed of one flask containing five explants. After 55 days, white LED and the ‘Red Ginger’ provided the highest number of shoots. For the number of leaves, the cultivar ‘Red Ginger’ and white LED lamps provided superior results. For shoot length (cm), the cultivar ‘Red Ginger’ kept under fluorescent lamps was superior, and ‘Pink Ginger’ presented superiority when cultivated under LED lights. Thus, even with differentiated responses among genotypes, the use of white LED lamps in the in vitro propagation of Alpinia purpurata ‘Red Ginger’ and ‘Pink Ginger’ cultivars is suggested.