ABSTRACT. French lavender (Lavandula dentata L.) is of great ornamental, medicinal, and aromatic interest. It is generally propagated vegetatively using stem cuttings. When using artificial lighting, a specific light composition can modify the entire plant phenology and is a factor that can be managed in controlled conditions. This study evaluated the rooting of stem cuttings and growth of lavender under four spectral LED lights. The LED lights used were: T0 (white LED, Roblan®), T1 (AP67 Milky, Valoya®), T2 (NS1, Valoya®), and T3 (AP673L Milky, Valoya®). The first phase evaluated the rooting of stem cuttings and initial development. The plants were then transferred to plastic pots to evaluate plant growth. In both rooting and growing phases, the plant morphological characteristics and water and light efficiencies were evaluated. Nutrient-uptake efficiencies were also evaluated after the growing phase. It was observed that cuttings rooted under the influence of T1 showed greater height. After the growing phase, plants under T3 showed better results in electricity use efficiency, water use efficiency, and nutrient-uptake efficiency and less nitrate leaching. They also presented more uniform growth with a compact canopy. Thus, T1 was better for the stem cuttings rooting phase, while T3 was better for growth and energy efficiency.

ABSTRACT: The optimization of resources and time in the production of quality seedlings within a legal framework is of vital importance for greenhouse vegetable crops. This study evaluated the electrical conductivity of the nutrient solution and its effect on the survival and growth of bell pepper and tomato seedlings propagated by cuttings. The electrical conductivities evaluated were 0.92, 1.25, 1.50, and 1.75 dS m-1. The experiment was conducted using a randomized complete block design with four replicates. The number of rooted plants, stem diameter, root length, number of leaves, leaf area, dry weight of leaves, stem, root, and total were determined. In addition, the following indices were determined: stem root index, slenderness index, leaf area ratio, specific leaf area, and pre-transplant horticultural quality index. In both crops, the highest number of rooted cuttings was obtained with the lowest electrical conductivity. Meanwhile, the average electrical conductivity favored leaf number, leaf area, biomass, and seedling quality indices. These results showed that the production of bell pepper and tomato seedlings can be done by cuttings using Stenier nutrient solution at electrical conductivities of 1.25 to 1.50 dS m-1 without affecting seedling quality.

RESUMO: A otimização de recursos e tempo na produção de mudas de qualidade dentro de um quadro legal é de vital importância para as hortaliças em estufa. O objetivo deste trabalho foi avaliar a condutividade elétrica da solução nutritiva e seu efeito na sobrevivência e no crescimento de mudas de pimentão e tomate propagadas por estaquia. As condutividades elétricas avaliadas foram 0,92, 1,25, 1,50 e 1,75 dS m-1. O experimento foi conduzido em delineamento de blocos ao acaso com quatro repetições. Foram determinados o número de plantas enraizadas, diâmetro do caule, comprimento da raiz, número de folhas, área foliar, massa seca das folhas, caule, raiz e total. Além disso, foram determinados os seguintes índices: índice de raiz do caule, índice de esbeltez, razão de área foliar, área foliar específica e índice de qualidade hortícola pré-transplante. Em ambas as safras, o maior número de estacas enraizadas foi obtido com a menor condutividade elétrica. Já a condutividade elétrica média favoreceu os índices de número de folhas, área foliar, biomassa e qualidade das mudas. Esses resultados mostram que a produção de mudas de pimentão e tomate pode ser feita por meio de estacas com solução nutritiva de Stenier em condutividades elétricas de 1,25 a 1,50 dS m-1 sem afetar a qualidade das mudas.

ABSTRACT: The objective of this study was to evaluate the production and quality of pruning and planting density as a function of cultural management. Two simultaneous experiments with the huacle chili were conducted. Experiment 1 consisted of planting density treatments of 2, 3 and 4 plants m -2 with a principal pruning of 3 stems per plant. Experiment 2 consisted of a planting density of 3 plants m -2 and three pruning treatments of 2 or 4 stems per plant and of no pruning. Growth, production and fruit quality was measured. The highest planting density significantly increased the leaf area index, yield and fruit production in terms of total dry matter. The fruit quality parameters were not affected. The leaf area index was lowest in the treatment with pruning to two branches and did not vary with pruning to 4 stems and no pruning. The highest yield and dry matter fruit production was obtained from plants with 4 stems, while the quality of the fruit was not affected.

RESUMEN: El chile huacle o chilhuacle es una variedad de Capsicum annum L. de importancia etnobotánica y cultural de Oaxaca, México. Se está produciendo una significativa reducción de su superficie cultivada al aire libre debido a diversos factores ambientales. El objetivo de este trabajo fue evaluar la producción y calidad en función del manejo cultural de la poda y la densidad de la plantación. Se realizaron dos experimentos simultáneos con pimiento huacle en Oaxaca (México), en un ciclo corto de cultivo de seis meses en un invernadero plástico sin control climático. El primero de densidad de plantación a 2, 3 y 4 plantas m-2, y el segundo de poda a 2, 4 tallos y sin poda. Se midieron algunos parámetros de crecimiento vegetativo, producción, de calidad del fruto y sólidos solubles totales. La mayor densidad de plantación incrementó significativamente el índice de área foliar, el rendimiento y producción de materia seca total de fruto, mientras que los parámetros de calidad de fruto no se vieron afectados. Las plantas podadas a 4 tallos no se afectaron en altura ni en grosor de tallo respecto a las sin poda. El índice de área foliar fue menor en la poda a dos brazos y no varió con la poda de 4 tallos y sin poda. El mayor rendimiento y producción de materia seca de fruto se obtuvo con las plantas a 4 tallos, mientras que la calidad de los frutos no se vio afectada.

Salinity is well known to reduce plant growth and yield by reducing water availability; it does so by interfering with both nutrient uptake and translocation. The objective was to determine the nitrate and potassium contents in xylem sap and the root-shoot transportation of both as a function of the salinity of the nutritional solution provided. We compared NO3-and K+ contents and flux in xylem sap collected from cut stems of tomato seedlings, based on electric conductivity (EC) tests among five nutrition solutions for soilless crops ranging from medium to high salinity. The EC was 2.2, 3.5, 4.5, 6, and 12 dS m-1. The concentration of nitrates and potassium in the xylem sap remained constant, while the external concentration in the rhizosphere varied greatly. Notwithstanding, the xylematic flux was strongly affected by the salinity of the nutritional solution: at maximum salinity, EC reached 3.5 dS m-1; at minimum, EC was 12 dS m-1. For similar reasons, the longest NO3- and K+ transportation distance between root and shoot was achieved when the EC read 3.5 dS m-1, but was reduced by up to 80% when EC was 12 dS m-1.

The nitrate content in leafy vegetables grown in hydroponic systems was studied. High levels of nitrate may be hazardous to human health. The European Commission indicates that lettuce plants grown in a greenhouse in winter should contain a nitrate concentration below 4,500 mg/kg (fresh weight). This study determined the nitrate contents of lettuces grown by float and nutrient film technique (NFT) in hydroponic systems, in greenhouse without a heating system at winter time. Four trials were carried out in Talca, Chile (south hemisphere) from May to September. Three cultivars of type butterhead lettuces (Lactuca sativa L. var. capitata): “Loreto”, “Floresta” and “Esmeralda” were evaluated. In the float system, the leafy nitrate content fluctuated between 1,344 and 3,839 mg/ kg and from 1,754 to 2,157 mg/kg at beginning and end of winter, respectively. The nitrate contents in lettuces grown in NFT, fluctuated from 2,552 to 2,818 mg/kg and between 2,676 to 3,100 mg/kg at beginning and end of winter time, respectively. Neither of lettuce cultivars surpassed the maximum nitrate content stipulated by the European Commission, nor were there consistent differences among them.

Se estudió el contenido de nitrato en lechugas cultivadas en sistemas hidropónicos. Altos niveles de nitrato pueden ser dañinos a la salud humana. La Comisión Europea indica que las plantas de lechuga cultivadas en invernadero en período invernal deberían contener una concentración de nitrato foliar menor a 4.500 mg/kg (peso fresco). En este estudio se determinaron los contenidos de nitrato de lechugas cultivadas en los sistemas hidropónicos de mesa flotante y nutrient film technique (NFT), en invernadero no calefaccionado y en invierno. Cuatro experimentos se realizaron en Talca, Chile, en período invernal (mayo a septiembre). Tres cultivares de lechuga tipo Española (Lactuca sativa L. var. capitata) fueron evaluados: “Loreto”, “Floresta” y “Esmeralda”. En el sistema flotante, el contenido de nitrato foliar fluctuó entre 1.344 y 3.839 mg/kg y desde 1.754 a 2.157 mg/kg a inicios y término del período invernal, respectivamente. Los contenidos de nitrato en cultivares de lechuga cultivados en el sistema NFT fluctuaron desde 2.552 a 2.818 mg/kg y entre 2.676 a 3.100 mg/kg a inicios y fin del invierno, respectivamente. Ninguno de los cultivares de lechuga sobrepasó el contenido máximo estipulado por la Comisión Europea y tampoco existieron diferencias consistentes entre ellas.