Manutenção do status hídrico de plantas de soja induzida por Etil-Trinexapac

Improving abiotic stress tolerance in plants by crop management is one of biggest goals of actual research, thus, plant growth regulators have a great potential in the physiological manure of crops. The objective of this work was to evaluate the effects of Trinexapac-Ethyl on soybean plants affected by drought stress during the reproductive stage. Four Trinexapac-Ethyl doses were evaluated (0, 50, 100, and 200 g ha-1 a.i.) and the induction or not of drought stress. The experimental design was completely randomized blocks in factorial design (4x2) with four replications. Relative water content was measured during drought stress and rehydration period. Protoplasmic tolerance and biometric parameters were determined after recovery period. Yield and yield components were determined at the end of crop cycle. Low intensity drought stress was verified at this work, which affected the plant growth but did not affect soybean yield. Trinexapac-Ethyl application resulted in maintenance of leaves relative water content, mainly at 200 g ha-1 dose, without affect biometric parameters and grain yield. This behavior is a great indicative of increase in soybean drought tolerance.Aumentar a tolerância de plantas cultivadas a estresses abióticos por meio de técnicas de cultivo é um desafio para a pesquisa, sendo que os reguladores vegetais apresentam grande potencial de utilização no manejo fisiológico de culturas. O presente estudo teve por objetivo avaliar os efeitos da aplicação de Etil-Trinexapac em plantas de soja submetidas a déficit hídrico. O experimento foi conduzido em esquema fatorial 4X2, em delineamento experimental de blocos casualizados, com quatro repetições. Foram testadas quatro doses de Etil-Trinexapac (0, 50, 100 e 200 g ha-1 i.a.) e dois regimes hídricos (irrigado e imposição de déficit hídrico na fase reprodutiva). O conteúdo relativo de água das folhas foi determinado durante o período de déficit hídrico e recuperação das plantas. Ao final deste período determinou-se a tolerância protoplasmática foliar, o acúmulo de matéria seca e a área foliar, e ao final do ciclo da cultura foram determinados os componentes da produção e a produção de grãos por planta. O déficit hídrico foi caracterizado como de baixa intensidade, afetando o crescimento e o desenvolvimento das plantas de soja, sem reflexos na produção de grãos. A aplicação de Etil-Trinexapac resultou na manutenção do conteúdo relativo de água das folhas, principalmente na dose de 200 g ha-1, sem afetar as variáveis biométricas e a produção de grãos das plantas, sendo um indicativo do aumento da tolerância à seca em plantas de soja

Inoculation of growth-promoting bacteria in the lettuce crop

Plant growth promoting bacteria (PGPB) are an alternative to increase the productivity of several crops, including lettuce. Several reports are found in the literature with the use of plant growth-promoting bacteria in lettuce cultivation, but most seek increments during the production of seedlings. Aiming to provide increments in the cultivation of lettuce in the field and to generate subsidies to technicians and producers, the present work aimed to study the influence of the application of commercial products based on Azospirillum brasilense, Bacillus subtilis + B. megaterium and Pseudomonas fluorescens, on agronomic characteristics and quality of crisp lettuce. The experiment was implemented in two locations, in a randomized block design, in a 4 x 3 factorial scheme, with four replications. The first factor refers to the application of different PGPB: control, without inoculation; inoculations with A. brasilense; B. subtilis + B. megaterium and P. fluorescens. The second factor was composed of three times of application of PGPB, the first being on the day of seedling transplantation (DAT), the second at 15 STR and the third on the day of seedling transplantation + 15 DAT. At 15 DAT, the relative chlorophyll content, plant height, head diameter, number of leaves per plant, leaf area, leaf dry mass, stem dry mass, root dry mass, total dry mass, root volume were evaluated. and root length. At harvest, the same variables analyzed at 15 DAT + leaf fresh mass, stem fresh mass, head fresh mass, root fresh mass, total fresh mass and leaf contents of nitrogen, phosphorus and potassium were analyzed. The inoculated plant growth-promoting bacteria did not promote a significant increase in the development of the lettuce cultivar Vera when compared to the control (without PGPB application)

Corn inoculated with Azospirillum brasilense associated with poultry litter fertilization

The use of organic fertilization can have a great contribution to the physiological and chemical aspects of plant leaves, and can be aided by the use of microorganisms that promote greater use of soil nutrients. The aim of this work was to study the gas exchange and foliar N, P and K contents of corn as a function of seed inoculation with A. brasilense associated with fertilization with poultry manage. The work was carried out in the field in two areas, with a randomized block design, in a 2x6 factorial scheme. The first factor was the inoculation of seeds with A. brasilense and control without inoculation. The second factor was six doses of poultry manage, which were defined as a function of the nutrient levels in the soil and in the poultry manage, thus using 0, 50, 100, 150, 200, 250% of the recommended dose for each area. In both areas, evaluations of gas exchange indices were carried out, such as the net CO2 assimilation rate (A), stomatal conductance (gs), leaf transpiration rate (E) and water use efficiency (WUE), as well as, analysis of nitrogen, phosphorus and potassium contents in leaves. The inoculation of corn seeds with A. brasilense significantly influenced the net CO2 assimilation rate. The doses of poultry manage had a positive influence on the potassium content of the leaves. The maximum foliar P content was reached with the dose of 5830 kg ha-1 of poultry manage.The use of organic fertilization can have a great contribution to the physiological and chemical aspects of plant leaves, and can be aided by the use of microorganisms that promote greater use of soil nutrients. In this work, the objective was to study the gas exchange and foliar N, P, and K contents of corn as a function of seed inoculation with A. brasilense associated with poultry litter fertilization. The work was carried out in the field in two areas, with a randomized block design, in a 2x6 factorial scheme. The first factor was the inoculation of seeds with A. brasilense and control without inoculation. The second factor was six doses of poultry litter, defined as a function of the nutrient content in the soil and in the poultry litter: 0, 50, 100, 150, 200, 250% of the recommended dose for each area. In both areas, gas exchange indexes were evaluated, such as photosynthetic rate (A), stomatal conductance (gs), leaf transpiration rate (E) and water use efficiency (WUE), as well as analysis of nitrogen, phosphorus and potassium in the leaves. Seed inoculation with A. brasilense decreased the photosynthetic rate of corn leaves and increased the phosphorus content in leaf biomass when compared to the control treatment. The doses of poultry litter increased the phosphorus and potassium contents of the leaves. The maximum foliar P content was reached with the dose of 5830 kg ha-1 of poultry litter

Azospirillum brasilense affects the antioxidant activity and leaf pigment content of Urochloa ruziziensis under water stress

Water stress leads to the formation of reactive oxygen species, resulting in degradation of leaf pigments and cell death. This study aimed at assessing the oxidative enzyme activity and photosynthetic pigment content in seeds and/or leaves of Urochloa ruziziensis (syn. Brachiaria) inoculated with Azospirillum brasilense under water stress. Assessments of soluble proteins, chlorophylls a and b and carotenoid contents, as well as the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) enzymes, were conducted at the beginning of the water stress process and also under severe water stress and during plant rehydration. Seed inoculation showed a reduction in the action of SOD, under water stress, with an increase after rehydration. POD exhibited an activity greater than CAT in all the assessments, but it did not differ statistically under severe water stress. CAT activity increased under severe stress in all treatments, particularly for leaf inoculation. Chlorophyll a was slightly degraded, maintaining the levels of the irrigated control, while the chlorophyll b and carotenoid contents, in plants subjected to leaf inoculation with A. brasilense, were higher under water stress. It was concluded that the leaf inoculation of U. ruziziensis with A. brasilense makes the plant more efficient at removing reactive oxygen species and protecting chlorophyll a

INFLUÊNCIA DE PROTETORES FÍSICOS COLORIDOS NAS TROCAS GASOSAS EM MUDAS DE CANAFÍSTULA [Peltophorum dubium (Spreng.) Taub.]

The utilization of physical protectors has been considered an efficient technique for direct sowing of different species, mainly native ones. Based on the importance of the species Peltophorum dubium for revegetation of degraded areas, tree planting and landscaping, this study evaluated gas exchanges in canafistula seedlings under the influence of physical protectors subjected to different luminosity rates. The experiment was carried out in pots Latossolo Vermelho Distroférrico, a typical soil of the study region. Seedlings of Peltophorum dubium  were evaluated at 30, 50, 70, 90, 110, and 130 days after sowing (DAS). Thus, the following treatments were adopted: T1, absence of physical protector (APP); T2, transparent physical protector (TPP); T3, transparent physical protector + blue cellophane (BPP) and T4, transparent physical protector + red cellophane (RPP). The evaluated characteristics were: stomatal conductance, transpiration, CO2 assimilation, CO2 concentration inside the substomatal chamber and water use efficiency. In general, all types of physical protectors led to higher mean values of gas exchanges during their permanence in the sowing site until 70 DAS, except for CO2 assimilation. However, water use efficiency was higher in APP seedlings at the same period.A utilização de protetores físicos é uma técnica eficiente na semeadura direta de espécies nativas. Devido à importância da espécie Peltophorum dubium para a utilização no repovoamento de áreas degradadas, arborização e paisagismo, determinou-se o comportamento fisiológico das plantas com a análise da influência de um protetor físico com diferentes taxas de luminosidade no processo das trocas gasosas das plantas. O experimento foi conduzido em vasos com o solo Latossolo Vermelho Distroférrico, típico da região, em vasos com solo. As plantas de Peltophorum dubium foram avaliadas aos 30, 50, 70, 90, 110 e 130 dias após a semeadura (DAS) com os tratamentos: T1, ausência de protetor físico (APF); T2, protetor físico transparente (PFT); T3, protetor físico transparente + celofane azul (PFA) e T4, protetor físico transparente + celofane vermelho (PFV). Foram avaliadas as seguintes características: condutância estomática, transpiração, assimilação de CO2, concentração de CO2 no interior da câmara subestomática e eficiência do uso de água. Os resultados obtidos mostraram que o protetor físico independentemente de sua coloração promoveu aumento dos valores médios de trocas gasosas durante a permanência dos protetores físicos no ponto de semeadura 70 DAS, exceto para assimilação líquida de CO2. No entanto, a eficiência do uso de água foi maior com APF 70 DAS

Initial development of plants of Peltophorum dubium and Leucaena leucocephala inoculated with diazotrophic bacteria

O presente trabalho teve como objetivo avaliar a influência de bactérias diazotróficas no desenvolvimento inicial de Peltophorum dubium e Leucaena leucocephala em casa de vegetação. O delineamento experimental foi o de blocos ao acaso em esquema fatorial 2 x 4 com quatro repetições, sendo que o primeiro fator foi formado pelas duas espécies florestais P. dubium e L. leucocephala, enquanto que o segundo fator está relacionado à microbiolização das sementes por estirpes das bactérias diazotróficas promotoras de crescimento Azospirillum brasilense, Bradyrhizobium elkanii, associação entre as duas bactérias e testemunha sem microbiolização. A microbiolização das sementes das espécies florestais com A. brasilense, B. elkanii e associação entre as bactérias A. brasilense e B. elkanii incrementaram a emergência de plântulas. Na canafístula, a A. brasilense, B. elkanii, isoladas ou em associação, elevaram a massa seca de parte aérea, comprimento de parte aérea e comprimento de sistema radicular, e reduziram diâmetro de coleto. Na leucena, a B. elkanii aumentou massa seca de raiz e reduziu diâmetro de coleto, e a A. brasilense incrementou massa seca de parte aérea e comprimento do sistema radicular, atingindo massa seca de parte aérea maior que a associação de A. brasilense e B. elkanii.Palavras-chave:  Canafístula; leucena; fixação biológica de nitrogênio; promoção de crescimento; rizobactérias. AbstractInitial development of plants of Peltophorum dubium and Leucaena leucocephala inoculated with diazotrophic bacteria. This research aimed to evaluate the influence of diazotrophic bacteria on initial development of Peltophorum dubium and Leucaena leucocephala in greenhouse. The experimental design was a randomized block in factorial 2 x 4 with four replications, with the first factor formed by the two forest species P. dubium and L. leucocephala, while the second factor was related to microbiolization seeds by strains of diazotrophic growth promoting bacteria Azospirillum brasilense, Bradyrhizobium elkanii, association between the two bacteria and non-microbiolization control. The microbiolization seeds of forest species with A. brasilense, B. elkanii and association between the bacteria A. brasilense and B. elkanii improved seedling emergence of canafistula and leucaena. In canafístula, the A. brasilense, B. elkanii alone or in combination increased the dry weight of shoot, length of shoot and root length, and reduced diameter collect. In leucaena, B. elkanii increased the root dry weight and reduced diameter collect, and A. brasilense increased the dry weight of shoot and root system length, with higher dry shoot than association of A. brasilense and B. elkanii.Keywords: Canafistula; leucena; biological nitrogen fixation; growth promotion; rhizobacteria.AbstractThis research aimed to evaluate the influence of diazotrophic bacteria on initial development of Peltophorum dubium and Leucaena leucocephala in greenhouse. The experimental design was a randomized block in factorial 2 x 4 with four replications, with the first factor formed by the two forest species P. dubium and L. leucocephala, while the second factor was related to microbiolization seeds by strains of diazotrophic growth promoting bacteria Azospirillum brasilense, Bradyrhizobium elkanii, association between the two bacteria and non-microbiolization control. The microbiolization seeds of forest species with A. brasilense, B. elkanii and association between the bacteria A. brasilense and B. elkanii improved seedling emergence of canafistula and leucaena. In canafístula, the A. brasilense, B. elkanii alone or in combination increased the dry weight of shoot, length of shoot and root length, and reduced diameter collect. In leucaena, B. elkanii increased the root dry weight and reduced diameter collect, and A. brasilense increased the dry weight of shoot and root system length, with higher dry shoot than association of A. brasilense and B. elkanii.Keywords: Canafistula; leucena; biological nitrogen fixation; growth promotion; rhizobacteria

Chemical management of Pilea microphylla in orchid seedlings

Espécies da família Orchidaceae são produzidas em larga escala para comercialização de suas flores. Entretanto, devido ao seu lento desenvolvimento, o substrato fica sujeito à infestação de plantas daninhas, como a brilhantina (Pilea microphylla). Assim, objetivou-se avaliar a seletividade de herbicidas à mudas de orquídeas do gênero Rhynchostylis ([Rhynchostylis gigantea Alba x Rhynchostylis gigantea] X Rhynchostylis gigantea Semi-Alba) e controle de P. microphylla. Adotou-se delineamento inteiramente casualizado, com quatro repetições por tratamento. Os herbicidas estudados foram: oxyfluorfen (0, 120, 240 e 480 g ha-1 i.a.), flumioxazin (0, 12,5, 25 e 40 g ha-1 i.a.), nicosulfuron (0, 20, 40 e 80 g ha-1 i.a.) e mesotrione (0, 96, 144 e 192 g ha-1 i.a.), com uma testemunha sem aplicação para cada molécula. Na ocasião da pulverização as plantas de orquídea apresentavam quatro folhas e 5 cm de altura, enquanto que a P. microphylla possuía 10 cm de altura. O nicosulfuron não controlou P. microphylla, enquanto o oxyfluorfen e o flumioxazin apresentaram eficiência de controle superior a 90% a partir dos 14 dias após a aplicação (DAA). A mesotrione demonstrou baixa capacidade de controle da infestante, atingindo em torno de 35% de eficiência aos 49 DAA. Todos os herbicidas foram seletivos às mudas do híbrido de Rhynchostylis. As moléculas oxyfluorfen e flumioxazin foram eficientes no controle da P. microphylla nos intervalos de doses testados.Orchidaceae species are produced on a large scale for commercialization of its flowers. However, because of its slow development, the substrate is subject to weed infestation, such as brilhantina (Pilea microphylla). Thus, we aimed to evaluate the selectivity of herbicides to the orchid seedlings of genre Rhynchostylis ([Rhynchostylis gigantea Alba x Rhynchostylis gigantea] X Rhynchostylis gigantea Semi-Alba) and control of P. microphylla. A completely randomized design with four replicates per treatment was adopted. The herbicides studied were oxyfluorfen (0, 120, 240, and 480 g ha-1 a.i.), flumioxazin (0, 12.5, 25 and, 40 g ha-1 a.i.), nicosulfuron (0, 20, 40, and 80 g ha-1 a.i.), and mesotrione (0, 96, 144, and 192 g ha-1 a.i.), with a control without application for each molecule. At the time of spraying, the plants of orchid presented four leaves and were 5 cm high, while P. microphylla was 10 cm high. Nicosulfuron did not control P. microphylla, while oxyfluorfen and flumioxazin showed control levels exceeding 90% on 14 days after application (DAA). The mesotrione showed low ability to control the weed, reaching around 35% efficiency at 49 DAA. All herbicides were selective to the hybrid seedlings Rhynchostylis. The oxyfluorfen and flumioxazin molecules were efficient in controlling P. microphylla in the tested dose ranges

Crescimento e produção da couve-da-Malásia submetida a adubação nitrogenada

The aim of this work was to evaluate, through the growth analysis, the effects of nitrogen doses on the development of Brassica campestris var. chinensis (Pak Choi). The experiment was carried out in a greenhouse, from October to November, 2007, in Marechal Cândido Rondon, Paraná. The experimental design was the randomized block, with five treatments (0, 60, 105, 150 and 195 kg ha-1 of N) and four replications. The hybrid used was Chouyou. The nitrogen was equally applied in three times, when in transplantation, and at seven and 14 days after the transplantation. The dry mass production, and the foliage area were weekly evaluated reaching the following indices of growth: relative and absolute growth rate, net assimilation rate, leaf area ratio, and specific leaf area. The fresh mass of the aerial part was also evaluated in the last collection. The increase of nitrogen fertilization positively affects the growth parameters, and provides an increased production with emphasis on the dose of 195 kg ha-1 of N.O presente trabalho teve como objetivo avaliar, através da análise de crescimento, o desenvolvimento e produção de Brassica campestris var. chinensis, híbrido Choyou, cultivada sob diferentes doses de adubação nitrogenada. O experimento foi conduzido em cultivo protegido, de outubro a novembro de 2007, em Marechal Cândido Rondon/PR. O delineamento experimental foi de blocos casualizados, com cinco tratamentos (0, 60, 105, 150 e 195 kg ha-1 de N) e quatro repetições. O nitrogênio foi aplicado parceladamente, em três partes iguais, nos momentos do transplantio e aos sete e 14 dias após o transplantio. A produção de massa seca e a área foliar das plantas foram avaliadas semanalmente para obtenção dos seguintes índices de crescimento: taxas de crescimento absoluto e relativo, taxa assimilatória líquida, razão de área foliar e área foliar específica. Na última coleta foi também avaliada a produção de massa fresca da parte aérea. O incremento na adubação nitrogenada afeta positivamente os parâmetros de crescimento e proporciona incremento na produção com destaque para a dose de 195 kg ha-1 de N

Urea and slow-release nitrogen in wheat grown inoculaded with Azospirillum

É conhecido que a aplicação a lanço de fontes nitrogenadas de liberação lenta é mais eficiente em solo com baixa umidade, sendo semelhante à ureia em condições de umidade adequada no solo. Assim objetivou-se avaliar o comportamento da cultura de trigo inoculado com Azospirillum brasilense cultivado com diferentes doses de nitrogênio (N) em cobertura fornecidos por ureia e fertilizante de liberação lenta (FLLN) em diferentes ambientes. Para isso foi desenvolvido um experimento sob delineamento em blocos casualizados em esquema fatorial 2 x 4. O primeiro fator foram as fontes de nitrogênio (ureia e FLLN) e o segundo pelas doses de N em cobertura (0,0; 60,0; 120,0 e 180,0 kg ha-1), sendo conduzido em dois ambientes Marechal Cândido Rondon – PR (MCR) e Corbélia – PR (COR). Na maturação da cultura foi avaliado: massa e número de grãos por espiga, comprimento de espigas, número de espiguetas, massa de mil grãos, produtividade, umidade de grãos, peso hectolitro e índice de colheita. Os resultados mostraram que as fontes proveram aumento na massa e número de grãos por espiga e massa de mil grãos. Considerando que a cultura de trigo em ambos locais foi inoculada com Azospirillum brasilense. As doses de 102 kg ha-1 de N e 118,56 kg ha-1 de N promoveram máximo número de grãos por espiga e massa de mil grãos, no ambiente COR. No ambiente MCR, uso de 142,49 kg ha-1 de N e 163,33 kg ha-1 de N proporcionou máxima produtividade e umidade de grãos, respectivamente. Em COR, uso de 118,56 kg ha-1 de N na fonte ureia proporcionou máxima produtividade enquanto a fonte com liberação lenta incrementou linearmente a produtividade até dose de 180 kg ha-1 de N. Em MCR ambas as fontes elevaram a produtividade até a dose de 142,5 kg ha-1 de N.It is known that the broadcast application of slow-release nitrogen sources are more efficient in soil with low humidity, similar to urea in adequate moisture conditions in the soil. Thus aimed to evaluate the behavior of the crop of wheat grown inoculated Azospirillum brasilense with different levels of nitrogen (N) coverage provided by urea and slow-release fertilizer (SRF) in different environments. For this experiment was carried out in a randomized block design in a factorial 2 x 4. The first factor were the sources of nitrogen (urea and SRF) and the second by N rates covering (0.0; 60.0; 120.0 and 180.0 kg ha-1), being conducted in two environments Marechal Cândido Rondon - PR (MCR) and Corbélia - PR (COR). In the culture maturation was evaluated: mass and number of grains per spike, spike length, number of spikelets, thousand grain weight, yield, grain moisture, hectolitre weight and harvest index. The results showed that the sources have provided increase in the mass and number of grains per spike and thousand grain weight. Considering that the wheat crop in both sites was inoculated with Azospirillum brasilense. Doses of 102 kg ha-1 N and 118.56 kg ha-1 N promoted maximum number of grains per spike and thousand grain weight, the COR environment. The environment MCR, use of 142.49 kg ha-1 N and 163.33 kg ha-1 N resulted in maximum productivity and grain moisture, averages, respectively. In COR, use of 118.56 kg ha-1 N in urea source provided maximum productivity while SRF source linearly increased productivity up to 180 kg ha-1 of N. Already in MCR both sources increase productivity up to a dose of 142.5 kg ha-1 of N.Se sabe que la aplicación de difusión de los fertilizantes de nitrógeno de liberación lenta es más eficiente en el suelo con poca humedad, similar a la urea en condiciones de humedad adecuados en el suelo. Por lo tanto el objetivo de evaluar el comportamiento cultivada cosecha de trigo inoculó con Azospirillum brasilense con diferentes dosis de nitrógeno (N) la cobertura proporcionada por urea y fertilizantes de liberación lenta (FLLN) en diferentes entornos. Para ello se realizó un experimento en un diseño de bloques al azar en un factorial 2 x 4. El primer factor fueron las fuentes de nitrógeno (urea y FLLN) y el segundo por dosis de nitrógeno en (0,0; 60,0; 120,0 y 180,0 kg ha-1), siendo llevado a cabo en dos entornos Marechal Cândido Rondon - PR (MCR) y Corbélia - PR (COR). En la maduración del cultivo se evaluaron: peso y número de granos por espiga, longitud de la espiga, número de espiguillas, peso de mil granos, rendimiento, humedad del grano, peso hectolítrico y el índice de cosecha. Los resultados mostraron que las fuentes se han proporcionado aumento de la masa y el número de granos por espiga y el peso de mil granos. Mientras que la cosecha de trigo en ambos lugares se inoculó con Azospirillum brasilense. Las dosis de 102 kg ha-1 de N y 118.56 kg ha-1 de N promovido máximo número de granos por espiga y peso de mil granos, el medio ambiente COR. En el entorno de MCR, el uso de 142.49 kg ha-1 de N y 163.33 kg ha-1 de N proporcionado la máxima productividad y la humedad del grano, respectivamente. En COR, el uso de 118.56 kg ha-1 de N en la fuente de urea proporciona la máxima productividad como fuente de liberación lenta linealmente aumento de la productividad de hasta 180 kg ha-1 de N. MCR en ambas fuentes de aumento de la productividad de hasta las dosis de 142.5 kg ha-1 de N