Creole corn seed promotes increase in production and nutritional aspects in hydroponic forage / Semente de milho crioula promove incremento nos aspectos produtivos e nutricionais da forragem hidropônica

The aimed of this study to assess the productivity and nutritional characteristics of hydroponic corn forage derived from bico de ouro creole seeds and AL-Bandeirante. Two treatments (T), each representing a corn seed variety, were randomly allocated to beds filled with a wood sawdust substrate: T1 (n=5) - bico de ouro creole seed variety, and T2 (n=5) - AL-Bandeirante hybrid seed variety. On the 13th day, forage was collected to assess seedling biometry, green and dry mass production, and bromatological analyses. The data were subjected to statistical analysis, with a 5% significance level. The creole seed variety yielded higher seedling height (17.53 cm), root length (10.19 cm), stem (5.37 cm), leaf (12.17 cm), and greater production of green mass (7.22 kg/m²) and dry matter (2.05kg/m²) (P<0.05). The AL-Bandeirante corn forage had higher dry matter content (39.18%), mineral matter (2.33%), non-fiber carbohydrate (31.88%), and estimated total digestible nutrients (68.14%) (P<0.05), while the creole corn forage had higher organic matter content (99.45%), ethereal extract (19.53%), neutral detergent fiber (45.56%), and cellulose (15.46%) (P<0.05). Crude protein, acid detergent fiber, and lignin were similar between the treatments (P>0.05). Despite the AL-Bandeirante variety yielding a higher concentration of certain nutrients, its forage productivity was significantly low. Therefore, under the conditions of this study, the use of the creole seed variety is recommended.(AU)

O objetivo com este estudo foi avaliar a produtividade e as características nutricionais da forragem hidropônica de milho derivada de sementes de crioulo bico de ouro e AL-Bandeirante. Dois tratamentos (T), cada um representando uma variedade de semente de milho, foram distribuídos aleatoriamente em canteiros preenchidos com substrato de serragem de madeira: T1 (n=5) - variedade de semente crioula bico de ouro e T2 (n=5) - AL-Bandeirante variedade de semente híbrida. No 13º dia foi coletada forragem para avaliação da biometria das plântulas, produção de massa verde e seca e análises bromatológicas. Os dados foram submetidos à análise estatística, com nível de significância de 5%. A variedade de semente crioula proporcionou maior altura de plântula (17,53 cm), comprimento de raiz (10,19 cm), caule (5,37 cm), folha (12,17 cm) e maior produção de massa verde (7,22 kg/m²) e matéria seca (2,05kg /m²) (P<0,05). A forragem de milho AL-Bandeirante apresentou maior teor de matéria seca (39,18%), matéria mineral (2,33%), carboidrato não fibroso (31,88%) e nutrientes digestíveis totais estimados (68,14%) (P<0,05), enquanto a forragem de milho crioulo apresentou maior teor de matéria orgânica (99,45%), extrato etéreo (19,53%), fibra em detergente neutro (45,56%) e celulose (15,46%) (P<0,05). Proteína bruta, fibra em detergente ácido e lignina foram semelhantes entre os tratamentos (P>0,05). Apesar da variedade AL-Bandeirante apresentar maior concentração de alguns nutrientes, a produtividade de forragem foi significativamente baixa. Portanto, nas condições deste estudo, recomenda-se o uso da variedade crioula de sementes.(AU)

Agronomic Behavior of Mexican Roselle Cultivars Produced under Protected Agricultural Conditions.

Growth dynamics and morphological traits are used to define the characteristics of roselle cultivars Hibiscus sabdariffa. The morpho-agronomic variability of plants was evaluated, as well as the concentration of macro and micronutrients in leaves of Mexican roselle cultivars in hydroponic and greenhouse conditions. The following roselle cultivars were studied: 'Cruza Negra', 'UAN16-2', 'Criolla Huajicori', 'UAN 6 Puga', 'UAN 25-1' and '4Q4'. The relative growth rate of the crops was fitted to a positive cubic, negative quadratic and positive linear model, whereas stem diameter, fitted to a linear model, had a negative quadratic response. The foliar surface of the cultivars '4Q4', 'Cruza Negra', 'UAN16-2' and 'Criolla Huajicori' was directly related to the size of the flower, the calyx and the corolla. Nitrogen and potassium are the elements that showed the highest concentration in the cultivars Criolla Huajicori and Cruza Negra, while in the other four cultivars the highest concentrations of minerals in the leaf were nitrogen and calcium. The leaves of cultivar 4Q4 provided the greatest amount of minerals, with 83,565 mg kg-1 dry basis. Criolla Huajicori was the cultivar that exhibited the tallest height, the most productive branches and the greatest calyx number per plant; however, Cruza Negra exhibited the highest yield by having the longest calyx.

Production and Physiological Quality of Seeds of Mini Watermelon Grown in Substrates with a Saline Nutrient Solution Prepared with Reject Brine.

The economically profitable production of crops is related, among other factors, to seed quality, the production system, and the water used in irrigation or preparation of nutrient solutions. Therefore, the objective was to evaluate the phenology, production, and vigor of seeds of mini watermelons grown in saline nutrient solution and different substrates. In the fruit and seed production phase, the experiment occurred in a greenhouse with five electrical conductivities of water for nutrient solution preparation, ECw (0.5, 2.4, 4.0, 5.5, and 6.9 dS m-1), and two growing substrates (coconut fiber and sand). We evaluated the physiological quality of seeds previously produced under the five electrical conductivities of water and two substrates. High salinities for the hydroponic cultivation of the mini watermelon cultivar 'Sugar Baby' accelerated fruit maturation and crop cycle, decreasing fruit size. However, in both substrates, the seed production of mini watermelons, seed viability, and seed vigor occurred adequately with a reject brine of 6.9 dS m-1 in the hydroponic nutrient solution. The seed production of 'Sugar Baby' mini watermelons using reject brine in a hydroponic system with coconut fiber and sand substrates is viable in regions with water limitations.

Effects of nitrogen and phosphorus availability on the early growth of two congeneric pairs of savanna and forest species / Efeitos da disponibilidade de nitrogênio e fósforo no crescimento inicial de dois pares congenéricos de espécies de savana e floresta

In the tropical region, savannas and seasonal forests, both highly diverse biomes, occur side by side, under the same climate. If so, that mosaic cannot be explained solely by climatic variables, but also by fire, water availability and soil status. Nutrient availability in the soil, especially nitrogen and phosphorus, has been postulated to explain the abrupt transitions between savannas and seasonal forests in tropical regions. Plants from these two biomes may present different nutritional strategies to cope with nitrogen and phosphorus limitation. We used two congeneric pairs of trees — each pair with a species from the savanna and another from the neighboring seasonal forest — to test whether savanna and forest species presented different nutritional strategies during their early development. We cultivated 56 individuals from each of these species in a hydroponics system with four treatments: (1) complete Hoagland solution, (2) Hoagland solution without nitrogen, (3) Hoagland solution without phosphorus, and (4) Hoagland solution without nitrogen and phosphorus. After 45 days, we harvested the plants and measured total biomass, root to shoot ratio, height, leaf area, and specific leaf area. Overall, savanna species were lighter, shorter, with smaller leaves, higher specific leaf areas, and higher root to shoot ratios when compared to the forest species. Nitrogen increased the performance of species from both biomes. Phosphorus improved the performance of the forest species and caused toxicity symptoms in the savanna species. Hence, savanna and forest species presented different demands and were partially distinct already as seedlings concerning their nutritional strategies.(AU)

Em regiões tropicais, savanas e florestas estacionais, biomas altamente diversos, ocorrem lado a lado, sob o mesmo clima. Sendo assim, esse mosaico não pode ser explicado somente por variáveis climáticas, devendo ser considerada a frequência e intensidade de incêndios, disponibilidade de água e status do solo. A disponibilidade de nutrientes no solo, especialmente nitrogênio e fósforo, tem sido postulada para explicar as transições abruptas entre savanas e florestas estacionais nos trópicos. Espécies vegetais desses dois biomas podem apresentar estratégias nutricionais diferentes para lidar com a limitação tanto de nitrogênio como de fósforo. Utilizamos dois pares de árvores congenéricas — cada par com uma espécie típica de savana e outra de floresta estacional vizinha — para testar se as espécies da savana e da floresta apresentaram estratégias nutricionais diferentes durante seu desenvolvimento inicial. Cultivamos 56 indivíduos de cada uma dessas espécies em um sistema hidropônico com quatro tratamentos: (1) solução Hoagland completa, (2) solução Hoagland sem nitrogênio, (3) solução Hoagland sem fósforo e (4) solução Hoagland sem nitrogênio e fósforo. Após 45 dias, colhemos as plantas e medimos a biomassa total, a relação raiz / parte aérea, altura, área foliar e área foliar específica. No geral, as espécies savânicas foram mais leves, menores em altura, área foliar e área foliar específica e apresentaram maiores razões entre biomassa radicular por biomassa aérea quando comparadas às espécies florestais. A oferta de nitrogênio aumentou o desempenho das espécies de ambos biomas. O fósforo melhorou o desempenho das espécies florestais e causou sintomas de toxicidade nas espécies savânicas. Concluímos que, já como mudas, espécies congenéricas de savana e floresta apresentaram demandas distintas e foram parcialmente diferentes em relação a suas estratégias nutricionais.(AU)

Effects of nitrogen and phosphorus availability on the early growth of two congeneric pairs of savanna and forest species / Efeitos da disponibilidade de nitrogênio e fósforo no crescimento inicial de dois pares congenéricos de espécies de savana e floresta

In the tropical region, savannas and seasonal forests, both highly diverse biomes, occur side by side, under the same climate. If so, that mosaic cannot be explained solely by climatic variables, but also by fire, water availability and soil status. Nutrient availability in the soil, especially nitrogen and phosphorus, has been postulated to explain the abrupt transitions between savannas and seasonal forests in tropical regions. Plants from these two biomes may present different nutritional strategies to cope with nitrogen and phosphorus limitation. We used two congeneric pairs of trees — each pair with a species from the savanna and another from the neighboring seasonal forest — to test whether savanna and forest species presented different nutritional strategies during their early development. We cultivated 56 individuals from each of these species in a hydroponics system with four treatments: (1) complete Hoagland solution, (2) Hoagland solution without nitrogen, (3) Hoagland solution without phosphorus, and (4) Hoagland solution without nitrogen and phosphorus. After 45 days, we harvested the plants and measured total biomass, root to shoot ratio, height, leaf area, and specific leaf area. Overall, savanna species were lighter, shorter, with smaller leaves, higher specific leaf areas, and higher root to shoot ratios when compared to the forest species. Nitrogen increased the performance of species from both biomes. Phosphorus improved the performance of the forest species and caused toxicity symptoms in the savanna species. Hence, savanna and forest species presented different demands and were partially distinct already as seedlings concerning their nutritional strategies.

Em regiões tropicais, savanas e florestas estacionais, biomas altamente diversos, ocorrem lado a lado, sob o mesmo clima. Sendo assim, esse mosaico não pode ser explicado somente por variáveis climáticas, devendo ser considerada a frequência e intensidade de incêndios, disponibilidade de água e status do solo. A disponibilidade de nutrientes no solo, especialmente nitrogênio e fósforo, tem sido postulada para explicar as transições abruptas entre savanas e florestas estacionais nos trópicos. Espécies vegetais desses dois biomas podem apresentar estratégias nutricionais diferentes para lidar com a limitação tanto de nitrogênio como de fósforo. Utilizamos dois pares de árvores congenéricas — cada par com uma espécie típica de savana e outra de floresta estacional vizinha — para testar se as espécies da savana e da floresta apresentaram estratégias nutricionais diferentes durante seu desenvolvimento inicial. Cultivamos 56 indivíduos de cada uma dessas espécies em um sistema hidropônico com quatro tratamentos: (1) solução Hoagland completa, (2) solução Hoagland sem nitrogênio, (3) solução Hoagland sem fósforo e (4) solução Hoagland sem nitrogênio e fósforo. Após 45 dias, colhemos as plantas e medimos a biomassa total, a relação raiz / parte aérea, altura, área foliar e área foliar específica. No geral, as espécies savânicas foram mais leves, menores em altura, área foliar e área foliar específica e apresentaram maiores razões entre biomassa radicular por biomassa aérea quando comparadas às espécies florestais. A oferta de nitrogênio aumentou o desempenho das espécies de ambos biomas. O fósforo melhorou o desempenho das espécies florestais e causou sintomas de toxicidade nas espécies savânicas. Concluímos que, já como mudas, espécies congenéricas de savana e floresta apresentaram demandas distintas e foram parcialmente diferentes em relação a suas estratégias nutricionais.

Effects of nitrogen and phosphorus availability on the early growth of two congeneric pairs of savanna and forest species

Abstract In the tropical region, savannas and seasonal forests, both highly diverse biomes, occur side by side, under the same climate. If so, that mosaic cannot be explained solely by climatic variables, but also by fire, water availability and soil status. Nutrient availability in the soil, especially nitrogen and phosphorus, has been postulated to explain the abrupt transitions between savannas and seasonal forests in tropical regions. Plants from these two biomes may present different nutritional strategies to cope with nitrogen and phosphorus limitation. We used two congeneric pairs of trees each pair with a species from the savanna and another from the neighboring seasonal forest to test whether savanna and forest species presented different nutritional strategies during their early development. We cultivated 56 individuals from each of these species in a hydroponics system with four treatments: (1) complete Hoagland solution, (2) Hoagland solution without nitrogen, (3) Hoagland solution without phosphorus, and (4) Hoagland solution without nitrogen and phosphorus. After 45 days, we harvested the plants and measured total biomass, root to shoot ratio, height, leaf area, and specific leaf area. Overall, savanna species were lighter, shorter, with smaller leaves, higher specific leaf areas, and higher root to shoot ratios when compared to the forest species. Nitrogen increased the performance of species from both biomes. Phosphorus improved the performance of the forest species and caused toxicity symptoms in the savanna species. Hence, savanna and forest species presented different demands and were partially distinct already as seedlings concerning their nutritional strategies.

Resumo Em regiões tropicais, savanas e florestas estacionais, biomas altamente diversos, ocorrem lado a lado, sob o mesmo clima. Sendo assim, esse mosaico não pode ser explicado somente por variáveis climáticas, devendo ser considerada a frequência e intensidade de incêndios, disponibilidade de água e status do solo. A disponibilidade de nutrientes no solo, especialmente nitrogênio e fósforo, tem sido postulada para explicar as transições abruptas entre savanas e florestas estacionais nos trópicos. Espécies vegetais desses dois biomas podem apresentar estratégias nutricionais diferentes para lidar com a limitação tanto de nitrogênio como de fósforo. Utilizamos dois pares de árvores congenéricas cada par com uma espécie típica de savana e outra de floresta estacional vizinha para testar se as espécies da savana e da floresta apresentaram estratégias nutricionais diferentes durante seu desenvolvimento inicial. Cultivamos 56 indivíduos de cada uma dessas espécies em um sistema hidropônico com quatro tratamentos: (1) solução Hoagland completa, (2) solução Hoagland sem nitrogênio, (3) solução Hoagland sem fósforo e (4) solução Hoagland sem nitrogênio e fósforo. Após 45 dias, colhemos as plantas e medimos a biomassa total, a relação raiz / parte aérea, altura, área foliar e área foliar específica. No geral, as espécies savânicas foram mais leves, menores em altura, área foliar e área foliar específica e apresentaram maiores razões entre biomassa radicular por biomassa aérea quando comparadas às espécies florestais. A oferta de nitrogênio aumentou o desempenho das espécies de ambos biomas. O fósforo melhorou o desempenho das espécies florestais e causou sintomas de toxicidade nas espécies savânicas. Concluímos que, já como mudas, espécies congenéricas de savana e floresta apresentaram demandas distintas e foram parcialmente diferentes em relação a suas estratégias nutricionais.

Effects of nitrogen and phosphorus availability on the early growth of two congeneric pairs of savanna and forest species / Efeitos da disponibilidade de nitrogênio e fósforo no crescimento inicial de dois pares congenéricos de espécies de savana e floresta

In the tropical region, savannas and seasonal forests, both highly diverse biomes, occur side by side, under the same climate. If so, that mosaic cannot be explained solely by climatic variables, but also by fire, water availability and soil status. Nutrient availability in the soil, especially nitrogen and phosphorus, has been postulated to explain the abrupt transitions between savannas and seasonal forests in tropical regions. Plants from these two biomes may present different nutritional strategies to cope with nitrogen and phosphorus limitation. We used two congeneric pairs of trees - each pair with a species from the savanna and another from the neighboring seasonal forest - to test whether savanna and forest species presented different nutritional strategies during their early development. We cultivated 56 individuals from each of these species in a hydroponics system with four treatments: (1) complete Hoagland solution, (2) Hoagland solution without nitrogen, (3) Hoagland solution without phosphorus, and (4) Hoagland solution without nitrogen and phosphorus. After 45 days, we harvested the plants and measured total biomass, root to shoot ratio, height, leaf area, and specific leaf area. Overall, savanna species were lighter, shorter, with smaller leaves, higher specific leaf areas, and higher root to shoot ratios when compared to the forest species. Nitrogen increased the performance of species from both biomes. Phosphorus improved the performance of the forest species and caused toxicity symptoms in the savanna species. Hence, savanna and forest species presented different demands and were partially distinct already as seedlings concerning their nutritional strategies.

Em regiões tropicais, savanas e florestas estacionais, biomas altamente diversos, ocorrem lado a lado, sob o mesmo clima. Sendo assim, esse mosaico não pode ser explicado somente por variáveis climáticas, devendo ser considerada a frequência e intensidade de incêndios, disponibilidade de água e status do solo. A disponibilidade de nutrientes no solo, especialmente nitrogênio e fósforo, tem sido postulada para explicar as transições abruptas entre savanas e florestas estacionais nos trópicos. Espécies vegetais desses dois biomas podem apresentar estratégias nutricionais diferentes para lidar com a limitação tanto de nitrogênio como de fósforo. Utilizamos dois pares de árvores congenéricas - cada par com uma espécie típica de savana e outra de floresta estacional vizinha - para testar se as espécies da savana e da floresta apresentaram estratégias nutricionais diferentes durante seu desenvolvimento inicial. Cultivamos 56 indivíduos de cada uma dessas espécies em um sistema hidropônico com quatro tratamentos: (1) solução Hoagland completa, (2) solução Hoagland sem nitrogênio, (3) solução Hoagland sem fósforo e (4) solução Hoagland sem nitrogênio e fósforo. Após 45 dias, colhemos as plantas e medimos a biomassa total, a relação raiz / parte aérea, altura, área foliar e área foliar específica. No geral, as espécies savânicas foram mais leves, menores em altura, área foliar e área foliar específica e apresentaram maiores razões entre biomassa radicular por biomassa aérea quando comparadas às espécies florestais. A oferta de nitrogênio aumentou o desempenho das espécies de ambos biomas. O fósforo melhorou o desempenho das espécies florestais e causou sintomas de toxicidade nas espécies savânicas. Concluímos que, já como mudas, espécies congenéricas de savana e floresta apresentaram demandas distintas e foram parcialmente diferentes em relação a suas estratégias nutricionais.

Afrocolombian Struggles for Food, Land, and Culture: The Case of El Tiple.

El Tiple is one of many marginalized Afrodescendant communities confined within a green desert located in the southwest region of Colombia. This green desert is most widely known as the second-largest sugarcane monoculture field in the Americas. Herein, we describe a transdisciplinary and participatory effort to understand agroindustrial expansion in the region through the lens of the El Tiple community. Using qualitative and quantitative methodologies, we characterized the socioenvironmental context of El Tiple in terms of ethnography, autoethnography, social cartography, and ethnobotany. We implemented a participatory approach to codevelop a technology-assisted strategy for strengthening the community's small-scale farming activities. Our contextual analysis results show systemic food dispossession, which arises from several factors, including dramatic land transformation, rapid depletion and contamination of natural assets, and biodiversity loss. All these factors are associated with the presence of bordering sugarcane plantations. In collaboration with community members, we designed, constructed, and analyzed a greenhouse hydroponic cultivation system as an actionable means to gradually restore local production of food and medicinal plants for the community. Our transdisciplinary and participatory approach demonstrates how academics can partner with vulnerable communities in the coproduction of knowledge and solutions to pressing social needs.

Coliformes totais e fecais em hortaliças de cultivos convencional, hidropônico e orgânico / Total and fecal coliforms in conventional, hydroponic and organic crops

Objetivo ­ Analisar e comparar a presença de coliformes totais e fecais em hortaliças de cultivos convencional, hidropônico e orgânico. Métodos ­ A presença de coliformes totais e fecais foi analisada em amostras de alface, da variedade crespa (Lactuca sativa var. cripa), a partir do seu enriquecimento com água peptonada 0,1% para inoculá-las em diluições de 10-1, 10-2 e 10-3 em Petrifilm EC (3M Company). Após a incubação a 37°C por 24 horas, as colônias foram contadas e o resultado foi expresso como UFC.g-1 de coliformes totais e UFC.g-1 de Escherichia coli. Resultados ­ Foram analisadas seis amostras de alface, sendo duas de cultivo tradicional, três de cultivo orgânico e uma de cultivo hidropônico. Somente uma delas se apresentou própria para consumo, uma vez que o número de coliformes totais não ultrapassou o limite exigido pela vigilância sanitária. Além disso, uma das amostras de alface orgânica estava contaminada com coliformes fecais. Conclusão ­ O presente estudo evidenciou que a maioria das amostras de alface orgânica apresentou um número maior de coliformes totais quando comparado aos outros tipos de cultivo, e uma delas estava contaminada com E. coli. Além disso, a maioria mostrou-se em desacordo com o padrão microbiológico estabelecido pela legislação brasileira

Objective ­ To analyze and compare the presence of total and fecal coliforms in conventional, hydroponic and organic crops. Methods ­ The presence of total and fecal coliforms was analyzed in lettuce samples from the crespa variety (Lactuca sativa var. Cripa) from their enrichment with 0.1% peptone water to inoculate them in 10-1, 10-2 and 10-3 in Petrifilm EC (3M Company). After incubation at 37 °C for 24 hours, the colonies were counted and the result was expressed as UFC.g-1 of total coliforms and UFC.g-1 of Escherichia coli. Results ­ Six lettuce samples were analyzed, two of them being traditional, three organic and one hydroponic. Only one of them presented itself for consumption, since the number of total coliforms did not exceed the limit required by sanitary surveillance. In addition, one of the organic lettuce samples was contaminated with fecal coliforms. Conclusion ­ The present study showed that the majority of the organic lettuce samples presented a higher number of total coliforms when compared to the other types of culture, and one of them was contaminated with E. coli. In addition, the majority were in disagreement with the microbiological standard established by Brazilian legislation

Investigation of the uptake of molybdenum by plants from Argentinean groundwater.

Some regions of Argentina are affected by high concentrations of molybdenum, arsenic and vanadium from natural sources in their groundwater. In particular, Mo levels in groundwater from Eduardo Castex (La Pampa, Argentina) typically exceed the guidelines for drinking water formerly established by WHO at 70 µg/L. Therefore, this study investigated the uptake of Mo in plants, using cress (Lepidium sativum L.) as a model using hydroponic experiments with synthetic solutions and groundwater from La Pampa. Cress grown from control experiments (150 µg/L Mo, pH 7) presented an average Mo concentration of 35.2 mg/kg (dry weight, d.w.), higher than the typical total plant range (0.7-2.5 mg/kg d.w.) in the literature. Using pooled groundwater samples (65.0-92.5 µg/L Mo) from wells of La Pampa (Argentina) as growth solutions resulted in significantly lower cress Mo levels (1.89-4.59 mg/kg d.w.) than were obtained for synthetic solutions of equivalent Mo concentration. This may be due to the high levels in these groundwater samples of As, V, Fe and Mn which are known to be associated with volcanic deposits. This research addressed the hitherto scarcity of data about the effect of various physicochemical parameters on the uptake of Mo in plants.

Agronomic and sensory evaluation of lettuce in hydroponic system

Lettuce is the most important leafy vegetable in Brazil. Hydroponic lettuce cultivation has grown due to the viability of harvesting throughout the year. In this context, this study aimed to evaluate the agronomic characteristics, color, and preference of curly lettuce in the NFT hydroponic system. Six lineages (6601-1A, 6601-2L, 7016-6A, 7119-1B, 7223-1A, and 7224-4A) and two commercial cultivars (Brida and Vanda) of lettuce were used, in a completely randomized blocks design with four replications. Shoot length, root length, stem length, number of leaves, stem diameter, plant diameter, shoot fresh mass, root fresh mass, chlorophyll content, instrumental color, and sensory characteristics were evaluated. As for agronomic evaluation, the bolting of 6601-2L lettuce was relevant in different attributes. The Vanda lettuce and the lineage 7016-6A presented best performances for shoot fresh mass (399.44 and 378.63 g, respectively), while the lineages 7119-1B and 6601-2L present the worst performance (279.50 and 273.13 g, respectively). There was variation in chlorophyll content and luminosity, however, the evaluators did not notice differences between lettuces for brightness or green color, as well as for crunchy texture. Lettuces 6601-2L, 7224-4A, 6601-1A, Brida, 7223-1A, and 7119-1B were preferred. The variation among plants may be due to different situations, such as harvesting times and bolting, and a direct relationship between agronomic properties and preference among lettuces has not been established yet.

Bromatological composition and dry matter production of corn hydroponic fodder

The objective was to evaluate sowing density influence on hydroponic corn fodder bromatological composition, harvested in different ages raised on grass mix substrate. The experimental design used was completely randomized with six replications for each treatment, using 2.0 m² plots (1.0 x 2.0 m). The densities were distributed into factorial array (4x4), consisting in four sowing densities (1.0, 1.5, 2.0 and 2.5 kg m-²) and four cutting ages (10, 15, 20 and 25 days). The dry matter content (DMC) and production (DMP) and crude protein (CP), acid detergent fiber (ADF), Fiber neutral detergent (FND) and ethereal extract (EE) were analyzed each cutting age. In terms of DMP (kg m-²), EE (%) and DMC (kg m-²), it is recommended to use the density 1.0 kg m-² with cutting age of 25 days. Regarding CP (%) the best result was at 15 days of cut and density 2.5 kg m-² and the values for FND (%) and ADF (%) were higher at 25 days at 2.0 kg density 2,0 kg m-². The choice of both best harvesting age and density will depend on what is desired of the nutritional forage (CP, EE, NDF, ADF, DMC and DMP) as well its destination, since very close values were found in all analyzes, regardless of density and age of harvest analyzed.(AU)

Bromatological composition and dry matter production of corn hydroponic fodder

The objective was to evaluate sowing density influence on hydroponic corn fodder bromatological composition, harvested in different ages raised on grass mix substrate. The experimental design used was completely randomized with six replications for each treatment, using 2.0 m² plots (1.0 x 2.0 m). The densities were distributed into factorial array (4x4), consisting in four sowing densities (1.0, 1.5, 2.0 and 2.5 kg m-²) and four cutting ages (10, 15, 20 and 25 days). The dry matter content (DMC) and production (DMP) and crude protein (CP), acid detergent fiber (ADF), Fiber neutral detergent (FND) and ethereal extract (EE) were analyzed each cutting age. In terms of DMP (kg m-²), EE (%) and DMC (kg m-²), it is recommended to use the density 1.0 kg m-² with cutting age of 25 days. Regarding CP (%) the best result was at 15 days of cut and density 2.5 kg m-² and the values for FND (%) and ADF (%) were higher at 25 days at 2.0 kg density 2,0 kg m-². The choice of both best harvesting age and density will depend on what is desired of the nutritional forage (CP, EE, NDF, ADF, DMC and DMP) as well its destination, since very close values were found in all analyzes, regardless of density and age of harvest analyzed.

Physiological responses of watercress to brackish waters and different nutrient solution circulation times / Respostas fisiológicas de agrião com águas salobras e diferentes tempos de circulação da solução nutritiva

Water scarcity and the use of brackish water are the main challenges for agricultural development. In view of this, the present study proposes to examine physiological responses of the broadleaf-cress crop in an NFT hydroponics system according to the use of brackish water and nutrient solution circulation times. The treatments were distributed in a randomized block design with five water salinity levels (ECw: 0.6, 1.6, 2.6, 3.6 and 4.6 dS m-1) and two nutrient solution circulation times (T1 = 10 min and T2 = 15 min), totaling 10 treatments with four replicates, which resulted in 40 experimental plots. The following variables were analyzed: net photosynthetic rate, stomatal conductance, transpiration, leaf proline content, shoot moisture content, stem diameter and root length. The maximum observed photosynthetic rates were 20.9 mmol m-2 s-1 (T1) and 20.0 mmol m-2 s-1 (T2). Maximum stomatal conductance was 0.44 mol m-2 s-1, which decreased by 63.4% at the highest salinity level. The increasing ECw levels in both growing cycles evaluated reduced gas exchanges, stem diameter and root length. The nutrient solution circulation time of 15 min provided the most satisfactory results for the analyzed variables.(AU)

A escassez hídrica e o uso de água salobras são os principais desafios para o desenvolvimento agrícola. Diante disto o objetivo deste trabalho foi avaliar respostas fisiológicas da cultura do agrião d água de folhas larga em sistema hidropônico NFT em função do uso de águas salobras e tempos de circulação da solução nutritiva. Os tratamentos foram distribuídos em delineamento em blocos casualizados, com cinco níveis de salinidade da água (CEa: 0,6; 1,6; 2,6; 3,6 e 4,6 dS m-1) e dois tempos de circulação da solução nutritiva, (T1 =10 e T2=15 min), totalizando 10 tratamentos com 4 repetições, resultando em 40 parcelas experimentais. As variáveis analisadas foram: taxa de fotossíntese líquida, condutância estomática, transpiração, teor foliar de prolina, teor de umidade da parte aérea das plantas, diâmetro doc aule e comprimento das raízes. A máxima fotossíntese observada foi de 20,9 mmol m-2 s-1 (T1) e 20,0mmol m-2 s-1 (T2), para a condutância estomática foi 0,44 mol m-2s-1 provocando decréscimo 63,4%. O aumento dos níveis de CEa, em ambos os ciclos de cultivo avaliados, reduziram os valores de trocas gasosas, diâmetro do caule e comprimento da raiz. O tempo de 15 min promoveu os resultados mais satisfatórios para as variáveis analisadas.(AU)

Nutraceutical Profiles of Two Hydroponically Grown Sweet Basil Cultivars as Affected by the Composition of the Nutrient Solution and the Inoculation With Azospirillum brasilense.

Sweet basil (Ocimum basilicum L.) is one of the most produced aromatic herbs in the world, exploiting hydroponic systems. It has been widely assessed that macronutrients, like nitrogen (N) and sulfur (S), can strongly affect the organoleptic qualities of agricultural products, thus influencing their nutraceutical value. In addition, plant-growth-promoting rhizobacteria (PGPR) have been shown to affect plant growth and quality. Azospirillum brasilense is a PGPR able to colonize the root system of different crops, promoting their growth and development and influencing the acquisition of mineral nutrients. On the bases of these observations, we aimed at investigating the impact of both mineral nutrients supply and rhizobacteria inoculation on the nutraceutical value on two different sweet basil varieties, i.e., Genovese and Red Rubin. To these objectives, basil plants have been grown in hydroponics, with nutrient solutions fortified for the concentration of either S or N, supplied as SO4 2- or NO3 -, respectively. In addition, plants were either non-inoculated or inoculated with A. brasilense. At harvest, basil plants were assessed for the yield and the nutraceutical properties of the edible parts. The cultivation of basil plants in the fortified nutrient solutions showed a general increasing trend in the accumulation of the fresh biomass, albeit the inoculation with A. brasilense did not further promote the growth. The metabolomic analyses disclosed a strong effect of treatments on the differential accumulation of metabolites in basil leaves, producing the modulation of more than 400 compounds belonging to the secondary metabolism, as phenylpropanoids, isoprenoids, alkaloids, several flavonoids, and terpenoids. The primary metabolism that resulted was also influenced by the treatments showing changes in the fatty acid, carbohydrates, and amino acids metabolism. The amino acid analysis revealed that the treatments induced an increase in arginine (Arg) content in the leaves, which has been shown to have beneficial effects on human health. In conclusion, between the two cultivars studied, Red Rubin displayed the most positive effect in terms of nutritional value, which was further enhanced following A. brasilense inoculation.

Adsorption of polyethylene microbeads and physiological effects on hydroponic maize.

About 90% of the plastic garbage remains in terrestrial ecosystems, and increasing evidence highlights the exposure of crops to plastic particles. However, the potential bioaccumulation of microplastics by plants and their effects on plants' physiology remains unexplored. Here, we evaluated the adsorption, potential uptake, and physiological effects of polyethylene (PE) microbeads in an experimental hydroponic culture of maize. Using isotope analysis, taking advantage of the different carbon isotope composition (δ13C) of fossil-derived PE and C4 plants (e.g., maize), we estimated that about 30% of the carbon in the rhizosphere of microplastic-exposed plants was derived from PE. Still, we did not find evidence of PE translocation to the shoots. Plastic bioaccumulation in the rhizosphere caused a significant decline in transpiration, nitrogen content, and growth. Our results indicate that plastic particles may accumulate in the rhizosphere, impairing water and nutrient uptake, and eventually reaching root eaters. Due to the implications for food production and livestock feeding, our findings encourage further research on the mechanism leading to the bioaccumulation of microplastics on the surface of belowground tissues.

Genome-guided insights of tropical Bacillus strains efficient in maize growth promotion.

Plant growth promoting bacteria (PGPB) are an efficient and sustainable alternative to mitigate biotic and abiotic stresses in maize. This work aimed to sequence the genome of two Bacillus strains (B116 and B119) and to evaluate their plant growth-promoting (PGP) potential in vitro and their capacity to trigger specific responses in different maize genotypes. Analysis of the genomic sequences revealed the presence of genes related to PGP activities. Both strains were able to produce biofilm and exopolysaccharides, and solubilize phosphate. The strain B119 produced higher amounts of IAA-like molecules and phytase, whereas B116 was capable to produce more acid phosphatase. Maize seedlings inoculated with either strains were submitted to polyethylene glycol-induced osmotic stress and showed an increase of thicker roots, which resulted in a higher root dry weight. The inoculation also increased the total dry weight and modified the root morphology of 16 out of 21 maize genotypes, indicating that the bacteria triggered specific responses depending on plant genotype background. Maize root remodeling was related to growth promotion mechanisms found in genomic prediction and confirmed by in vitro analysis. Overall, the genomic and phenotypic characterization brought new insights to the mechanisms of PGP in tropical Bacillus.

Physiological role of silicon in radish seedlings under ammonium toxicity.

BACKGROUND: High concentrations of ammonium as the sole nitrogen source may result in physiological and nutritional disorders that can lead to reduced plant growth and toxicity. In this study, we hypothesized that ammonium toxicity in radish seedlings (Raphanus sativus L.) might be mitigated by the incorporation of silicon (Si) into applied nutrient solution. To examine this possibility, we conducted a hydroponic experiment to evaluate the effects of five concentrations of ammonium (1, 7.5, 15, 22.5, and 30 mmol L-1 ) on the photosynthesis, green color index, stomatal conductance, transpiration, instantaneous water-use efficiency, and biomass production of radish in the absence and presence (2 mmol L-1 ) of Si. The experimental design was a randomized block design based on a 2 × 5 factorial scheme with four replicates. RESULTS: The highest concentration of applied ammonium (30 mmol L-1 ) was found to reduce the photosynthesis, transpiration and total dry biomass of radish seedlings, independent of the presence of Si in the nutrient solution. However, at lower ammonium concentrations, the application of Si counteracted these detrimental effects, and facilitated the production of seedlings with increased photosynthesis, greater instantaneous water-use efficiency, and higher total dry biomass compared with the untreated plants (without Si). Transpiration and stomatal conductance were affected to lesser extents by the presence of Si. CONCLUSION: These findings indicate that the addition of Si to nutrient solutions could provide an effective means of alleviating the unfavorable effects induced by ammonium toxicity at concentrations of less than 30 mmol L-1 . © 2020 Society of Chemical Industry.

Morpho-Anatomical and Physiological Responses Can Predict the Ideal Period for the Transplantation of Hydroponic Seedlings of Hymenaea courbaril, a Neotropical Fruit Tree.

Hydroponics is an excellent alternative approach for the production of seedlings, given the growing demand for fruiting trees for the reforestation or recuperation of degraded natural landscapes. In most cases, however, little is known about the optimal period for the maintenance of the seedling in the hydroponic system. Given this, we decided to investigate the hypothesis that morpho-anatomical and physiological alterations can be used to predict the optimal timing for the transplantation of the seedlings to the soil substrate, thereby guaranteeing the most cost-effective application of the hydroponic system. We selected Hymenaea courbaril L., an important Neotropical fruit tree, as the model for this study. We cultivated H. courbaril seedlings in a static hydroponic system and evaluated morpho-anatomical, physiological, and growth parameters over the course of seedling development (30, 60, 90, 120, 150, and 180 days after transplantation; DAT). We observed an interesting relationship between the increase in the density (SD) and conductance (gsw) of the stomata up to 120 DAT, which reflected higher rates of photosynthesis (A), but also a reduced efficiency in the use of water. In the subsequent intervals, the SD of the plants and the diameter of the radicular xylemic vessels elements (RVE) decreased, in an attempt to increase the efficiency of the use of this resource. We also observed an increase in the thickness of the palisade parenchyma (PP) prior to 120 DAT, which did not reflect a general increase in the thickness of the mesophyll, indicating an adjustment in the thickness of the spongiform parenchyma (SP). We also observed a progressive increase in photosynthetic efficiency up to 120 DAT, based on parameters such as the absorption flux energy per active reaction center (ABS/RC) and the photosynthetic performance index (PIABS), but after this period these indices decreased progressively. However, as the PIABS is an indicator of the plant's tolerance, its decline was associated with an increase in the dissipation of energy (DI0/RC), which indicates that, after 120 DAT, the plant pots may become a stress factor that limit the growth of H. courbaril seedlings. The results of the present study indicate conclusively that a 120-day period is the optimum for the maintenance of the H. courbaril seedlings in the hydroponic system, and also confirm the hypothesis that the morpho-anatomical and physiological responses observed in the plants can be used to predict the ideal period for the transplantation of the seedlings, contributing to a reduction in production time of the hydroponic system.

Analysis of Nostoc muscorum biomass production in a hydroponic system / Análisis de la producción de biomasa de Nostoc muscorum en sistema hidropónico / Análise da produção de biomassa de Nostoc muscorum num sistema hidropônico

Abstract Nostoc is a genus of filamentous cyanobacteria with biotechnological applications in human nutrition, biomedicine, biofertilization and commercial production of biofuels. However, the low growth rate in liquid medium due to its periphytic nature and its tendency to form biofilms, limits its large-scale production. Therefore, the aim of this study was to evaluate the biomass production of Nostoc muscorum in a modified hydroponic system. Cultures of N. muscorum were made by triplicate, in a hydroponic system under semicontrolled conditions of temperature (29 ± 13 °C), light intensity (32 ± 54 µmol/m2/s) and photoperiod (12 hours), for a total of 23 days inside a greenhouse. Temperature, pH, conductivity and dry biomass production were monitored on alternating days. The results showed that the maximum dry biomass production was 0.2276 ± 0.0114 g/m2/day, and the average productivity was 0.4149 ± 0.0207 g/m2/day. The maximum biomass production of N. muscorum was achieved on day thirteen with 0.3185 ± 0.0159 g/m2/day. The correlation statistical analysis of environmental variables did not show significant differences; thus, temperature, pH and electrical conductivity did not affect the biomass production of N. muscorum. Consequently, the algal growth was influenced by the species physiology only. The support used in the hydroponic system allowed the adhesion and development of the algae mucilaginous layer without requiring drying periods as in conventional crops. The hydroponic system provided a continuous flow of nutrients hat could prevent the attack of opportunistic bacteria and fungi, generating a high growth rate of N. muscorum. The hydroponic system represents a viable alternative for the production of N. muscorum biomass under greenhouse conditions at large scale.

Resumen Nostoc es un género de cianobacterias filamentosas con aplicaciones biotecnológicas en nutrición humana, biomedicina, biofertilización y producción comercial de biocombustibles. Sin embargo, su baja tasa de crecimiento en medio líquido por su naturaleza perifítica y su tendencia a formar biofilms, limita su producción a gran escala. Por lo tanto, el objetivo de este estudio fue analizar la producción de biomasa de Nostoc muscorum en un sistema hidropónico modificado. Para ello, se realizaron cultivos de N. muscorum por triplicado, en un sistema hidropónico bajo condiciones semicontroladas de temperatura (29 ± 13°C), intensidad lumínica (32 ± 54 µmol/m2/s) y fotoperiodo (12 horas), durante 23 días en un invernadero. La temperatura, el pH, la conductividad eléctrica y la producción de biomasa seca, fueron monitoreados en días alternados. Los resultados arrojaron que la producción máxima de biomasa seca fue de 0.2276 ± 0.0114 g/m2/día, y la productividad promedio fue de 0.4149 ± 0.0207 g/m2/día. A su vez, la producción máxima de biomasa de N. muscorum se obtuvo el día trece con 0.3185 ± 0.0159 g/m2/día. El análisis estadístico de correlación de variables ambientales no arrojó diferencias significativas, por lo que la temperatura, el pH y la conductividad eléctrica no afectaron la producción de biomasa de N. muscorum. Consecuentemente, el crecimiento algal fue influenciado por la fisiología de la especie. El soporte empleado en el sistema hidropónico permitió la adherencia y el desarrollo de la capa mucilaginosa de la cianobacteria sin requerir períodos de desecación como en los cultivos convencionales. El sistema hidropónico proporcionó un flujo continuo de nutrientes que podría prevenir el ataque de bacterias y hongos oportunistas, generando una alta tasa de crecimiento. De este modo, este sistema hidropónico representa una alternativa viable para la producción de biomasa de N. muscorum en condiciones de invernadero a gran escala.

Resumo Nostoc é um gênero de cianobactérias filamentosas com aplicações biotecnológicas em nutrição humana, biomedicina, biofertilização e produção comercial de biocombustíveis. Entretanto, sua baixa taxa de crescimento em meio líquido, devido à sua natureza perifítica e sua tendência a formar biofilmes, limita sua produção em larga escala. Portanto, o objetivo deste estudo foi analisar a produção de biomassa de Nostoc muscorum num sistema hidropônico modificado. Para isso, foram realizadas culturas de N. muscorum em triplicata num sistema hidropônico sob temperatura (29 ± 13°C) e intensidade da luz (32 ± 54 µmol/m2 /s) semicontroladas com fotoperíodo de 12 horas durante 23 dias numa estufa. A temperatura, o pH, a condutividade elétrica e a biomassa seca foram monitorados em dias alternados. Os resultados mostraram que a produção máxima de biomassa seca foi de 0,2276 ± 0,0114 g/m2 /dia e a produtividade média foi de 0,4149 ± 0,0207 g/ m2 /dia. No entanto, a produção máxima de biomassa de N. muscorum foi obtida no dia treze com 0,3185 ± 0,0159 g/m / dia. A análise estatística da correlação de variáveis ambientais não mostrou nenhuma diferença significativa, de modo que a temperatura, o pH e a condutividade eléctrica não afetaram a produção de biomassa de N. muscorum e o crescimento foi influenciado pela fisiologia da espécie. O suporte utilizado permitiu a adesão e desenvolvimento da camada mucilaginosa das algas sem a necessidade de períodos de secagem como nas culturas convencionais. O sistema hidropônico proporcionou um fluxo contínuo de nutrientes que impede o ataque de bactérias e fungos oportunistas, gerando uma alta taxa de crescimento. Portanto, este sistema hidropônico representa uma alternativa viável para a produção de biomassa de N. muscorum em larga escala sob condições de estufa.