Copper (Cu) is a micronutrient essential for plant development. However, in excess, it is toxic to plants and may cause various physiological and morphological changes. The study of the growth of plants exposed to excess Cu is important for the development of phytoremediation programs and for understanding the mechanisms involved in the tolerance of this metal. In this context, the objective of this research was to evaluate the effect of excess copper on photosynthetic responses and root morphology of Hymenaea courbaril L. Biometric measurements, gas exchange, root morphology, and Cu content in tissues and indices (TI and TF) were assessed, involving metal content and biomass. Up to a concentration of 200 mg kg −1 , Cu favored growth, gas exchange, and root morphology of the plants under study. At a higher concentration (800 mg kg −1) in the soil, it affected plant growth and caused a decrease in photosynthetic rate. Biochemical limitations in photosynthesis were observed, as well as lower maximum net photosynthetic rate (A max), respiration rate in the dark (R d), light compensation point (LCP), light saturation point (LSP), and apparent quantum yield (α), when exposed to excess Cu. Root length, surface area, mean diameter, root volume, dry biomass, and specific root length decreased with high Cu concentrations in the soil. Cu was accumulated in the roots as a mechanism of tolerance to the excess of this metal in order to preserve the most metabolically active tissues present in the leaves. At a concentration of 800 mg kg −1 , copper also caused inhibition of the root system. Plants of H. courbaril showed tolerance to excess Cu in the soil and can be indicated for the recovery of areas contaminated with this metal.
RESUMOObjetivou-se com este trabalho verificar o efeito da matéria orgânica como componente de substratos para mudas micropropagadas de abacaxizeiro cv. Pérola em fase de aclimatização. Mudas micropropagadas de abacaxizeiro cv. Pérola, selecionadas de acordo com o peso (aproximadamente 2 g), foram plantadas em bandejas de isopor de 72 células de 120 cm 3 contendo proporções de substratos com terra, esterco bovino, Plantmax e matéria orgânica. O delineamento estatístico utilizado foi o inteiramente casualizado com 4 repetições e 3 plantas por parcela. As avaliações foram feitas 90 dias após o plantio, quando se avaliou: altura da planta, comprimento de raiz, peso de matéria fresca de raiz e parte aérea, peso de matéria seca de raiz e parte aérea e número de folhas. Com os resultados obtidos, conclui-se que a matéria orgânica tem efeito significativo no desenvolvimento das mudas. Com o substrato contendo terra, esterco e Plantmax foi obtido o melhor desenvolvimento das raízes e parte aérea.Termos para indexação: Cultura de tecidos, Ananas comosus, matéria orgânica. ABSTRACTThe objective of this work was to evaluate the effect of the organic matter as component of substrata for micropropagated plants of pineapple cv. Pérola in the acclimatization phase. Micropropagated plants were selected according to the weight (approximately 2g) and planted in trays with 72 cels of 120 cm 3 , containing substrata made of soil, bovine manure, Plantmax and organic matter at different proportions. At 90 days after planting, the following parameters were evaluated: height of the plant, root length, weight of fresh matter of root and aerial part, dry matter weight of root and aerial part and number of leaves. The obtained results allowed to conclude that the organic matter has significant effect on the development of the seedlings. The best results for the development of the roots and aerial part were obtained with substratum containing soil, manure and Plantmax.
Objetivou-se avaliar o efeito da sacarose e pH na germinação in vitro de grãos de pólen das cultivares Valência, Natal e Pêra. Para testar o efeito da sacarose, os grãos de pólen foram distribuídos uniformemente em placas de Petri contendo meio de cultura básico constituído de 10 gL-1 de ágar, 800 mgL-1 de nitrato de cálcio e 200 mgL-1 de ácido bórico, acrescido de sacarose (0, 50, 100, 150 e 200 gL-1). Para verificação do pH satisfatório, os grãos de pólen foram inoculados em meio de cultura contendo 10 gL-1 de ágar e 800 mgL-1 de nitrato de cálcio, 200 mgL-1 de ácido bórico,100 gL-1 de sacarose e pH de 3,5; 4,0; 4,5; 5,0; 5,5; 6,0; 6,5. Após inoculação, os grãos de pólen foram incubados em BOD a 25ºC por 12 horas. A porcentagem de germinação foi obtida com auxílio de microscópio óptico com objetiva de 10 X. Para todas as cultivares estudadas, a maior porcentagem de germinação foi obtida com 100 gL-1 de sacarose e o maior número de grãos de pólen germinados foi verificado em pH 6,5, sendo observado que maiores valores de pH aumentaram também a quantidade de polens estourados para as cultivares Natal e Pêra e diminuíram para Valência.
-The effect of organic fertilization with cattle manure on fertility properties of soils with different clay contents was evaluated; as well as the influence of cattle manure fertilization on the production of lettuce, and on subsequent arugula and common chicory grown in these soils. The experiment with pot plants was arranged in randomized blocks and analyzed in a 3x6 factorial design with four replications. The treatments consisted of three soil types with different clay contents (166; 362; 565 g kg -1) and six cattle manure rates (0; 10; 20; 40; 80, and 160 t ha -1 ). Batches of each soil were manured, limed, filled in pots, moistened, and incubated for 30 days. Then, mineral base fertilization was applied and one lettuce seedling per each pot was grown. After lettuce harvest, the residual effect of organic fertilization was assessed in two subsequent crops, first arugula and then common chicory. The application of up to 160 t ha -1 cattle manure reduces soil acidity and increases nutrient contents, particularly of P, K and Zn, in soils with 165 to 565 g kg -1 clay content. Fertilization with cattle manure at rates of up to 160 t ha -1 increases electrical conductivity of soils, without affecting growth and yield of the leafy vegetables. Cattle manuring increases the yield of lettuce, as well as of arugula and common chicory grown afterwards.Keywords: Lactuca sativa. Cichorium intybus. Eruca sativa. Organic fertilization. Sucessive crop. ATRIBUTOS DE FERTILIDADE E PRODUÇÃO DE HORTALIÇAS FOLHOSAS EM SOLOS ADUBADOS COM ESTERCO BOVINORESUMO -O presente trabalho teve como objetivos avaliar o efeito da adubação com esterco bovino em atributos de fertilidade de solos com diferentes teores de argila e, verificar a influência da adubação com esterco bovino na produção de alface americana, e da rúcula e almeirão, cultivados de forma sucessiva a alface. O experimento foi realizado em vasos, em delineamento em blocos ao acaso, com os tratamentos arranjados em esquema fatorial 3x6 com quatro repetições. Os tratamentos foram constituídos por três solos com diferentes teores de argila (166; 362; 565 g kg -1 ) e seis doses de esterco bovino (0; 10; 20; 40; 80 e 160 t ha -1 ). Porções de cada solo receberam esterco bovino e calcário, foram transferidas para vasos, umedecidas e incubadas por 30 dias. A seguir, efetuou-se adubação mineral de plantio e cada vaso recebeu uma muda de alface. Após a colheita da alface, para avaliar o efeito residual da adubação orgânica foram realizados dois cultivos sucessivos, um de rúcula e outro de almeirão. A aplicação de até 160 t ha -1 de esterco bovino diminui a acidez e, aumenta os teores de nutrientes, particularmente P, K e Zn em solos com teores de argila de 165 a 565 g kg -1 . A adubação com esterco bovino em doses de até 160 t ha -1 aumenta a condutividade elétrica dos solos, e esse acréscimo não prejudica o crescimento e a produção de hortaliças folhosas. A adubação com esterco bovino aumenta a produção de alface, como também a de rúcula e almeirão, cultivados de forma suc...
Os microrganismos exercem grande importância para o desenvolvimento dos vegetais por meio da produção de diversos compostos, como o ácido 3-indol acético (AIA), sintetizado por bactérias. No entanto, ainda são incipientes as pesquisas relatando o efeito da inoculação destas bactérias nas plantas. Dessa forma, o objetivo desse estudo foi avaliar a produção in vitro de AIA por bactérias diazotróficas cultivadas na presença ou ausência do triptofano (Trp) e o efeito da inoculação destas estirpes em sementes de alface (Lactuca sativa L.). Inicialmente, foi instalado um experimento em delineamento inteiramente casualizado (DIC) em esquema fatorial 19 × 2, sendo 19 estirpes bacterianas cultivadas em meios contendo ou não o Trp, com quatro repetições. Foi observado que o Trp contribui para a maior produção de AIA pela maioria das estirpes. Posteriormente, seis dessas estirpes foram selecionadas para inoculação em sementes de alface em dois experimentos, o primeiro em gerbox e o outro em bandejas contendo substrato comercial. Foi utilizado o DIC em esquema fatorial 8 × 2, sendo sete estirpes bacterianas e um controle sem inoculação e presença ou ausência do Trp no meio de cultivo, com quatro repetições. A inoculação com a maioria das estirpes contribuiu para o aumento da taxa de germinação das sementes, comprimento radicular e peso da matéria seca da parte aérea, no entanto, o excesso de AIA produzido por algumas estirpes quando cultivadas na presença de Trp pode interferir no desenvolvimento das mudas de alface.Palavras chave adicionais: fito-hormônios, bactérias promotoras do crescimento vegetal, triptofano, sustentabilidade.
<span lang="EN-US">Coffee cultivation has undergone significant changes, especially with regard to the mechanization process of the various existing operations that were previously carried out manually by the workers. It is observed that the intensification of mechanized activities can expose workers to noise levels capable of compromising their hearing health. In this sense, the objective of the present study was to determine the level of occupational noise in the activities of mechanized and semi-mechanized harvesting of coffee fruits and compare them with the limits of tolerance of the current legislation. The occupational noise level was determined considering the exposure of homogeneous groups, using an integrative meter for personal use, noise dosimeter, electromechanically calibrated and with field calibration. The results demonstrate that the noise levels found are above the limits allowed for an 8-hour working day. The highest observed level was 100.66 dB (A) in the sweeping operation with the blower equipment and the lowest level 89.05 dB (A) in the auxiliary activity of the selected collection equipment Vicon H3000. Harvesting activity with a portable </span><span lang="EN-US">mechanical stripper <span>equipment showed a noise level 4.07% higher compared to harvesting with automotive harvester equipment.</span></span>
ABSTRACT:Micropropagation is an alternative to produce orchid plants in large scale. However, this process presents losses during acclimatization. Exogenous proline use in vitro plant tissue culture can reduce the stress of the plant acclimatization phase. We aimed to verify the growth of orchids in different micropropagation systems with the addition of proline in the culture medium. Cattleya walkeriana plants were obtained from the germination of seeds in culture medium. Seeds were germinated in MS medium, added 20 g. L -1 of sucrose, solidified with 6 g. L -1 of agar and pH adjusted for 5,8. The cultures were incubated in a growth room with temperature of 24 ± 2 0 C, under photoperiod of 16 h. After 5 months, 1-cm long seedlings were placed in a culture vessel according to the treatments, which were composed of two micropropagation systems (conventional and natural ventilation) and three proline concentrations (0, 1, and 2 g·L -1 ). The experiment was carried out in an entirely randomized design consisting of a 2 × 3 factorial, for a total of 6 treatments, each with 5 replicates. The natural ventilation system with the use of proline (1 g·L -1 ) promoted higher dry mass accumulation and better control of water loss by plants.
INDIRECT SOMATIC EMBRYOGENESIS INCoffea arabica L. CV. OBATÃ 1 ABSTRACT It was aimed with this work to study the indirect somatic embryogenesis in Coffea arabica L. cv. 'Obatã', including the steps of induction, differentiation and regeneration of plants. Leaf segments withdrawn from plants under field conditions were disinfected with 70% alcohol for 1 , 1% sodium hypochlorite for 15 and inoculated in 'CI' medium (callus induction) supplemented with 2,4 D (0, 1, 2 and 4 mg.L -1 ) and kinetin (0, 2, 4 and 8 mg.L -1 ). Later, the callus were transferred to the 'CD' medium (callus differentiation) to which was added 2,4-D (0, 1, 2 and 4 mg.L -1 ) and BAP (0, 2, 4 and 8 mg.L -1 ). During the regeneration step, friable embryogenic callus were inoculated in 'R' medium supplemented with BAP (0, 2, 4 and 6 mg.L -1 ) and sucrose (0, 15, 30, 45 and 60 g.L -1 ). The culture media utilized had their pH adjusted to 5.6 ± 1 before being autoclaved. The experiments were kept in growth room at 26 ± 1 o C. Over the steps of callus 1. Parte da Dissertação apresentada pelo primeiro autor à UNIVERSIDADE FEDERAL DE LAVRAS/UFLA, Caixa Postal 37 37200-000 LAVRAS, MG, como parte das exigências do curso de Mestrado em Agronomia, área de concentração Fitotecnia.
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