The nitrate accumulation in plant tissues can occur due to low light availability. However, published studies have not linked nitrate accumulation to photosynthetic photon flux (PPF) measured during the growing period. This study aimed to evaluate the effect of the reduction of photosynthetic photon flux and the concentration of nitrate in the nutrient solution on agronomic characteristics and accumulation of nitrate in lettuce grown in hydroponics. The trial design was entirely randomized in a factorial scheme (4 x 2) with three repetitions, and four shading levels: 0, 30, 50, and 80% and two nitrate levels in nutrient solution: 5 and 10 mmol L-1. The dry matter production decreased directly and linearly with the reduction of light. The lowest level in nitrate solution also led to reduction in dry mass yield. The maximum accumulation of nitrate reached 966.3 mg kg-1 fresh mass, with PPF of 118 μmol/m²/s and 140 mg L-1 of N-NO3-1 (below the maximum levels recommended by the European Union), and the minimum of 200 mg kg-1 with PPF of 455 μmol/m²/s and 70 mg L-1 of N-NO3-1 in the nutrient solution. The reduction of nitrate in the nutrient solution from 140 to 70 mg L-1 led to the reduction of nitrate accumulation in shoots, but also caused a decrease in the production of phytomass of shoots, as well as reduced leaf area significantly.
RESUMOA goiabeira é afetada por uma doença complexa que envolve dois agentes, o fitonematoide Meloidogyne enterolobii e o fungo Fusarium solani (Mart.) Sacc. Ambos, associados, causam o declínio da goiabeira, levando à expressão de sintomas como apodrecimento progressivo do sistema radicular, queima dos bordos e bronzeamento das folhas, amarelecimento, queda das folhas e morte da planta (GOMESet al., 2011).Em áreas contaminadas, torna-se imprescindível o uso de genótipos resistentes a M. enterolobii, pois o nematoide é o agente predisponente à doença. No Brasil, ainda não foi constatada resistência a M. enterolobii em cultivar em comerciais de P. guajava. A resistência a M. enterolobii foi encontrada em araçazeiros da espécie Psidium cattleyanum (Sabine) por CARNEIRO et al. (2007), ALMEIDA et al. (2009) e MIRANDA et al. (2012. Entretanto, em P. cattleyanum tanto a resistência quanto a susceptibilidade foram igualmente encontradas, dependendo do acesso avaliado (MIRANDA et al. 2012). Este trabalho teve por objetivo avaliar a resistência de genótipos de P. cattleyanum a M. enterolobii.Os araçazeiros utilizados foram provenientes de propagação seminífera de dois acessos de P. cattleyanum (115 e 117), cujos meio irmãos foram considerados resistentes a M. enterolobii por MIRANDA et al. (2012). O acesso 115 foi proveniente de arborização pública em Campos dos Goytacazes-RJ e o acesso 117 proveniente da restinga de São João da Barra-RJ. Mudas obtidas por propagação seminífera desses acessos foram transplantadas e cultivadas -NOTA -
RESUMO orange nursery trees produced in treatment 4 (Pêra / RL / FD) had vigor nearest sweet orange nursery trees produced with interstock (Pêra / RL). The production Pera sweet orange nursery trees interstocked for traditional system, with the rootstock CS or FD and interstock sweet orange Bahia was not possible because of the low viability and vigor of the shoots. Key words: Poncirus trifoliata, Flying Dragon, CitrumeloSwingle, grafting incompatibility, inarching.A laranjeira Pêra é uma das cultivares de laranja doce mais plantadas no Brasil, devido a sua versatilidade de uso tanto na indústria quanto para o consumo in natura. O limoeiro Cravo é ainda o porta-enxerto mais utilizado em extensas áreas de produção e sua diversifi cação tem sido recomendada, principalmente após o surgimento do declínio e da morte súbita (POMPEU JUNIOR & BLUMER, 2008).A diversifi cação de porta-enxertos para a laranjeira Pêra tem sido mais restrita quando relacionada às demais cultivares de laranjeiras, por sua reportada incompatibilidade com o Poncirus trifoliata e seus híbridos, como o citrumeleiro Swingle, além de outros porta-enxertos, como o limoeiro Volkameriano (DONADIO, 1999).A interenxertia é uma prática que é usada, quando se deseja unir duas plantas que, sabidamente, são incompatíveis, ou quando se pretende diminuir o vigor da cultivar copa. Essa técnica consiste em interpor um fragmento de uma planta entre o enxerto e o porta-enxerto. Assim, uma planta interenxertada apresenta três partes geneticamente diferentes (porta-enxerto, interenxerto e enxerto) e dois locais de enxertia (FACHINELLO et al., 2005). No caso -NOTA -I Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF), 28013-602, Campos dos Goytacazes, RJ, Brasil.
One of the methods to determine the tolerance of plants to water stress is the observation of germination of seeds under stress induced in laboratory conditions. Thus, the aim was to evaluate the response of four common bean cultivars to water deficit simulated under laboratory conditions. Two common landrace genotypes acquired from farmers (FORT 07 and FORT 08) and two commercial cultivars, IAPAR 81 and Serrano were evaluated. The different levels of water deficit were induced with mannitol solution. The experimental design was completely randomized and a factorial scheme 5 × 4 (osmotic potential x genotypes), with four replications. The characteristics: primary root protrusion, seed vigor, normal and abnormal seedling, seedling and root length, fresh and dry weight of seedling and root were evaluated. By reducing the osmotic potential seedling vigor bean was more affected than the primary root protrusion. Regardless of cultivar, there was a significant and progressive reduction in the normal seedlings percentage from potential −0.3 MPa. The IAPAR 81 and FORT 07 cultivars showed higher tolerance to water deficit compared to other cultivars.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.