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.

Resumo O potássio é um nutriente que afeta o crescimento e a qualidade dos frutos do abacaxizeiro. O estudo objetivou avaliar a qualidade de frutos em abacaxizeiro ‘Vitória’ submetido à aplicação de doses de potássio. O experimento foi realizado de maio de 2017 a novembro de 2018, em São Francisco do Itabapoana (RJ), Brasil. O delineamento foi em blocos ao acaso, com quatro repetições. Os tratamentos foram cinco doses de K2O: 0; 6; 12; 18 e 24 g planta-1, aplicadas na forma de KCl, parceladas em duas aplicações, após a indução floral. As massas frescas do fruto e da coroa, os diâmetros do fruto e do cilindro central,os comprimentos do fruto e da coroa, a acidez titulável, os sólidos solúveis, a vitamina C, o pH do suco e a relação sólidos solúveis/acidez titulável foram avaliados. A adubação potássica promoveu maiores comprimento, diâmetro e massa de fruto. Os valores de acidez titulável, dos sólidos solúveis e da vitamina C aumentaram linearmente em função das doses de potássio. A adubação potássica promove a melhoria da qualidade dos frutos de abacaxizeiro ‘Vitória’ em condições de campo.

Abstract Potassium is a mineral nutrient that affects the growth and quality of pineapple fruits. This study aimed to evaluate the quality of ‘Vitória’ pineapple fruits submitted to application of potassium doses. The experiment was carried out from May 2017 to November 2018, in the municipality of São Francisco do Itabapoana (RJ), Brazil. The design was randomized blocks, with four replicates. Treatments were five K2O doses: 0; 6; 12; 18 and 24 g plant-1, applied as KCl, split into two applications after flower induction. Fruit and crown fresh masses, fruit and crown diameters, fruit and crown lengths, titratable acidity, soluble solids, vitamin C, juice pH and soluble solids/titratable acidity ratio were evaluated. Potassium fertilization promoted greater fruit length, diameter and mass. Titratable acidity, soluble solids and vitamin C values increased linearly as a function of potassium doses. Potassium fertilization improves the quality of ‘Vitória’ pineapple fruits under field conditions.

RESUMO O potássio (K) é um dos macronutrientes mais exigido pelos cultivos agrícolas sendo o cloreto de potássio a fonte mais utilizada. No entanto, esse fertilizante não é recomendado para diversas culturas devido ao seu alto teor de cloro promover perdas na qualidade do produto final, sendo substituído pelo sulfato de potássio. Objetivou-se neste trabalho avaliar a produção, os teores de macronutrientes, de óleos essenciais e de linalol em frutos de coentro submetidos a diferentes fontes e doses de potássio. O experimento foi realizado em casa de vegetação, em caixas de plásticos com capacidade de 46 kg, tendo uma mistura de solo com areia como substrato. O delineamento experimental foi de blocos ao acaso, em arranjo fatorial 2x4, sendo duas fontes de potássio (cloreto e sulfato de potássio) e quatro doses (50, 100, 150 e 200 mg de K/kg de substrato), com quatro repetições. As maiores produtividades de frutos, teor de fósforo e de enxofre nos frutos foram obtidos em plantas adubadas com K2SO4. A aplicação de doses crescentes de potássio, independente da fonte, resultou em aumento no teor de K, decréscimo nos teores de Ca e não afetou os teores de N e Mg nos frutos. A maior concentração de óleos essenciais nos frutos (0,15 g) e linalol nos óleos essenciais (0,42 mg), foram obtidas quando se aplicou, respectivamente, 153,8 e 131,3 mg de K/kg de substrato, utilizando-se K2SO4.

ABSTRACT Potassium (K) is one of the most required agricultural crop macronutrients, with potassium chloride being the most applied source. However, this fertilizer is not recommended for several crops due to its high chlorine content, promoting final product quality losses, thus being replaced by potassium sulphate. The aim of the present study was to evaluate the production and macronutrient, essential oil and linalool contents of coriander fruits submitted to different potassium sources and doses. The research was performed in a greenhouse, in plastic 46 kg boxes applying a mixture of soil and sand as substrate. The experimental design was of randomized blocks, applying a 2x4 factorial arrangement, with two potassium sources (potassium chloride and sulphate) at four doses (50, 100, 150 and 200 mg of K/kg substrate), performing four replicates. The highest fruit yields, and phosphorus and sulfur fruit contents were verified in plants fertilized with K2SO4. The application of increasing potassium doses, regardless of the source, resulted in increased K and decreased Ca contents and did not affect N and Mg fruit levels in the fruits. The highest essential oil concentration in fruits (0.15 g) and linalool in essential oils (0.42 mg) were verified when 153.8 and 131.3 mg of K/kg substrate using K2SO4 were applied, respectively.

Resumo Objetivou-se avaliar a influência das deficiências de macronutrientes e de boro nas características físico-química dos frutos de abacaxizeiro da cultivar Vitória. O delineamento experimental foi em blocos ao acaso, com oito tratamentos (solução completa, -N, -P, -K, -Ca, -Mg, -S e -B) e seis repetições. A condução do experimento foi de outubro de 2016 a março de 2018, e as variáveis avaliadas foram: massas frescas do fruto e da coroa, diâmetro do fruto, comprimentos do fruto e da coroa, volume e massa do suco, acidez titulável (AT), sólidos solúveis (SS), vitamina C, pH do suco e relação SS/AT. Todos os tratamentos com deficiência de nutrientes reduziram a massa fresca do fruto. Nos tratamentos -N e -Ca houve redução de 41,9 e 35,3%, respectivamente, na massa fresca da coroa. O diâmetro dos frutos sob deficiência de N, K e Mg, foi menor, já o comprimento do fruto, os sólidos solúveis e o pH do suco foram menores no tratamento deficiente em N. Deficiências isoladas de cada um dos macronutrientes e de B reduziram a massa fresca do fruto inteiro e do fruto sem coroa. O nutriente que mais limitou o tamanho e qualidade do fruto de abacaxizeiro ‘Vitória’ foi o nitrogênio.

Abstract The objective of this study was to evaluate the influence of macronutrient and boron deficiencies on physico-chemical characteristics of pineapple fruits, ‘Vitoria’ cultivar. The experimental design was a randomized complete block with eight treatments (complete solution, -N, -P, -K, -Ca, -Mg, -S and -B) and six replicates. The experiment was conducted from October 2016 to March 2018, and the variables evaluated were: fresh fruit and crown mass, fruit diameter, fruit and crown length, juice volume and mass, titratable acidity (TA), soluble solids (SS), vitamin C, juice pH and SS/TA ratio. All treatments with nutrient deficiency reduced the fresh fruit mass. In treatments -N and -Ca there was a reduction of 41.9 and 35.3%, respectively, in the crown fresh mass. Fruits diameter under N, K and Mg deficiency was lower, fruit length, soluble solids and juice pH were lower in treatment with N deficiency. Isolated deficiencies of each of the macronutrients and B reduced the mass of the whole fruit and the crownless fruit. The nutrient that most limited the size and quality of ‘Vitoria’ pineapple fruit was nitrogen.