Brazilian Archives of Biology and Technology
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/12090
Navegar
3 resultados
Resultados da Pesquisa
Item Nitrogen metabolism in coffee plants subjected to water deficit and nitrate doses(Instituto de Tecnologia do Paraná - Tecpar, 2023-03-24) Rocha, Brunno César Pereira; Martinez, Hermínia Emília Prieto; Ribeiro, Cléberson; Brito, Danielle SantosNitrogen uptake is essential for coffee growth and development, resulting in important effects on the biomass and final crop yield. Thus, like most nutrients, nitrogen is absorbed by the roots using water as a mean of transport, so that water stress and nitrogen can directly and indirectly affect various physiological processes. The aim of this paper was to evaluate the nitrogen metabolism in young plants of four varieties of coffee trees (Coffea arabica L.) submitted to water deficit (WD) and nitrogen supply. We have done a triple factorial (2 x 4 x 4) experiment entirely randomized. The plots received combinations of high or low N doses (7mmol/L and 2.8 mmol/L NO3 -), four water potentials (0; -0.4; -0.8; and -1.6 Mpa), and four varieties (Mundo Novo IAC379-19, Acauã F6 of IBC - PR 82010, Catuaí Vermelho IAC 44, and Catuaí Amarelo IAC 62). One hundred and forty days after the I of the experiment (140 days after the beginning of N stress and 82 days after the beginning of WD stress) the activity of the enzymes nitrate reductase (NR) and glutamine synthetase (GS), concentration of nitrate, free proline, amino acids (TAA), and total proteins were determined in samples of leaf and root tissues. There were differences between varieties independently of WD and N dose for leaf NR, being ‘Acauã’ the cultivar that presented the highest and ‘Catuaí Vermelho’ the lowest value to this trait. The WD promoted an increase on the proline concentration in the roots. With low N dose, the activity of GS presented linear increases in response to WD. It was concluded that in young coffee plants under WD, proline can be involved in the osmotic adjustment, having its synthesis in the roots increased. Under WD, plants with good nitrogen nutrition presented larger leaf concentration of soluble amino acids and total soluble proteins. The varieties studied do not present differentiated responses to WD.Item Tolerance of arabica coffee cultivars for aluminum in nutritive solution(Instituto de Tecnologia do Paraná - Tecpar, 2011-09) Macedo, Célia Maria Peixoto de; Lopes, José Carlos; Amaral, José Augusto Teixeira do; Fonseca, Aymbiré Francisco Almeida da; Amaral, José Francisco Teixeira doThis work aimed to evaluate the Coffea arabica cultivars for aluminum toxicity tolerance, in modified Hoagland solution. A completely randomized design with five repetitions in a factorial 4 x 4 (cultivar x combinations of aluminum) was used. After 44 days of the sowing, were transferred ten seedlings each cultivar germinated in the absence of Al 3+ to solution without Al 3+ , and ten for solution with Al 3+ ; ten seedlings each cultivar germinated in presence of Al 3+ to solution without Al 3+ , and ten for solution with Al 3+ . In the treatment with aluminum, the element was added to the nutritive solution in the concentration of 0.83 mmol L -1 as Al 2 (SO 4 ) 3 .16H 2 O. The cultivars Catuaí Amarelo IAC 62 and Iapar 59 were tolerant to the aluminum; cultivar Oeiras presented intermediate tolerance, while cultivar Obatã IAC 1669-20 was sensitive. The tolerance of the coffee cultivars to the aluminum during the initial development of the seedlings did not depend on the presence of aluminum in the germination phase.Item Microbial activity in soil cultivated with different summer legumes in coffee crop(Instituto de Tecnologia do Paraná - Tecpar, 2011-01) Balota, Elcio Liborio; Chaves, Julio César DiasA field experiment was conducted for ten years in a sandy soil in the north part of the Paraná State, Brazil. The soil samples were collected at 0-10 cm depth, both under the coffee canopy and in the inter row space between the coffee plants, in the following treatments: Control, Leucaena leucocephala, Crotalaria spectabilis, Crotalaria breviflora, Mucuna pruriens, Mucuna deeringiana, Arachis hypogaea and Vigna unguiculata. The legume crops influenced the microbial activity, both under the coffee canopy and in the inter row space. The cultivation of Leucaena leucocephala increased the microbial biomass C, N and P. Although L. leucocephala and Arachis hypogaea provided higher microbial biomass, the qCO 2 decreased by up to 50% under the coffee canopy and by about 25% in the inter row space. The soil microbial biomass was enriched in N and P due to green manure residue addition.