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Fixa??o biol?gica de nitrog?nio em cultivares de feijoeiro estimada pela abund?ncia natural de 15N / Biological nitrogen fixation in common bean cultivars estimated by 15N natural abundancePACHECO, Rafael Sanches 19 August 2014 (has links)
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Previous issue date: 2014-08-19 / CNPq / The 15N natural abundance technique to measure the biological nitrogen fixation (BNF) in legumes is based on the slight enrichment of 15N observed in soils to the atmosphere and does not require the application of labelled fertilizers. The objectives of this work were: to quantify the BNF contribution in common bean (Phaseolus vulgaris) cultivars under field conditions through the 15N natural abundance technique; to evaluate the agronomic performance of these cultivars under inoculation; to estimate the isotopic fractionation value during BNF (B value) of common bean cultivars grown in nutrient solution. Two experiments were conducted in greenhouse in nutrient solution without N, in the years 2012 and 2013 in Serop?dica, RJ. Three common bean cultivars were evaluated. Plant biomass was sampled at different growth stages, where the N natural abundance was analyzed. In 2012 experiment, the nodules showed positive ?15N, with deltas of 6.63? and 8.18? in Grafite and Radiante cultivars, respectively. The B value in shoot was ?0.919?, ?0.734? and ?0.724? for cultivars Grafite, Ouro Negro and Radiante, respectively. In 2013 experiment, the nodules showed great enrichment in 15N, with 9.11? and 8.36? deltas in Radiante and Grafite cultivars. The B value in shoot was -1.06? and -1.40? for cultivars Radiante and Grafite, respectively. The average B value in shoots of common bean cultivars was ?1.23?, and the B value of ?1.2 was used in the calculation of the BNF contribution in the field experiments of this study. Eight common bean cultivars were grown in field conditions in 2011 and 2012, with two N sources (inoculation with commercial inoculant with rizhobia or fertilization with 90 kg ha-1 of mineral N), with four replications, at Embrapa Rice and Bean in Santo Antonio de Goias, GO. Biomass of the shoot, root, nodules and grains were sampled, and total N and 15N natural abundance were analyzed in shoots and grains. In the experiment in 2011, the Ouro Negro cultivar produced higher nodule mass under inoculation, also at reproductive stages, and the Jalo Precoce and Radiante cultivars showed the lowest nodule mass. The grain yield of the eight cultivars was 1614 and 2942 kg ha-1 under inoculation or mineral N, respectively. Under inoculation, the Ouro Negro cultivar showed the highest N accumulation in shoots and grains and the highest grain yield, reaching 2200 kg ha-1, equivalent to 73% of yield under mineral N. In 2011, the N accumulation derived from BNF in grains of the eight cultivars ranged from 5.8 to 16.4 kg ha-1, which corresponded to a BNF contribution of 17% and 33% in Marfim and Ouro Negro cultivars, respectively. In 2012, the higher nodule mass occurred in Vereda and Estilo cultivars, in the first and second samples, respectively, whereas Radiante cultivar had the lowest nodule mass. The average grain yield of the eight cultivars was 3284 and 3919 kg ha-1 under inoculation and mineral N, respectively. The N accumulation derived from BNF in grains was 68.4, 38.7, and 21.6 kg ha-1 in Ouro Negro, Grafite and Radiante cultivars, respectively, corresponding to a BNF contribution of 49, 29 and 32%. The method of 15N natural abundance provided the identification of BNF potential for the supply of N in different common bean genotypes, arising as a tool for providing subsidies to guide breeding programs in order to increase BNF efficiency. / A t?cnica da abund?ncia natural de 15N para mensurar a fixa??o biol?gica de nitrog?nio (FBN) em leguminosas baseia-se no ligeiro enriquecimento de 15N observado nos solos em rela??o ? atmosfera e n?o exige a aplica??o de fertilizantes marcados. Os objetivos deste trabalho foram: quantificar, atrav?s da t?cnica da abund?ncia natural de 15N, a contribui??o da FBN em cultivares de feijoeirocomum (Phaseolus vulgaris) em condi??es de campo; avaliar o desempenho agron?mico dessas cultivares sob inocula??o; estimar o valor do fracionamento isot?pico durante a FBN (valor B) de cultivares de feijoeiro crescidas em solu??o nutritiva. Foram conduzidos dois experimentos em casa de vegeta??o, em solu??o nutritiva isenta de N, nos anos de 2012 e 2013, em Serop?dica, RJ. Foram avaliadas tr?s cultivares de feijoeiro, efetuando-se coletas de biomassa em diferentes est?dios e analisando-se a abund?ncia natural de 15N do material vegetal. No experimento em 2012, os n?dulos apresentaram ?15N positivo, com deltas de 6,63? e 8,18? nas cultivares Grafite e Radiante, respectivamente. O valor B da parte a?rea foi de ?0,92?, ?0,73? e ?0,72?, nas cultivares Grafite, Ouro Negro e Radiante, respectivamente. No experimento em 2013, os n?dulos apresentaram deltas de 9,11? e 8,36? nas cultivares Radiante e Grafite. O valor B da parte a?rea foi de ?1,06? e ?1,40? nas cultivares Radiantee Grafite, respectivamente. O valor B m?dio da parte a?rea das cultivares foi de ?1,23?, sendo o valor B de ?1,2 utilizado nos c?lculos da contribui??o da FBN nos experimentos de campo desse estudo. Oito cultivares de feijoeiro foram crescidas em condi??es de campo em 2011 e 2012, sob duas fontes de N (inocula??o com inoculante comercial com riz?bio ou aduba??o com 90 kg ha-1 de N mineral), com quatro repeti??es, na Embrapa Arroz e Feij?o, em Santo Antonio de Goi?s, GO. Foram efetuadas amostragens de biomassa de parte a?rea, raiz, n?dulos e gr?os e an?lises de N total e abund?ncia natural de 15N na parte a?rea e gr?os. No experimento em 2011, a cultivar Ouro Negro produziu maior massa de n?dulos sob inocula??o, inclusive nos est?dios reprodutivos, e as cultivares Jalo Precoce e Radiante apresentaram a menor massa de n?dulos. O rendimento m?dio de gr?os das oito cultivares foi de 1614 e 2942 kg ha-1 sob inocula??o ou N mineral, respectivamente. Sob inocula??o, a cultivar Ouro Negro apresentou os maiores ac?mulos de N na parte a?rea e nos gr?os e a maior produtividade, atingindo 2200 kg ha-1 de gr?os, equivalente a 73% da produ??o sob N mineral. Em 2011, o ac?mulo de N derivado da FBN nos gr?os das oito cultivares variou de 5,8 a 16,4 kg ha-1, que correspondeu a 17% e 33% de contribui??o da FBN nas cultivares Marfim e Ouro Negro, respectivamente. Em 2012, a maior massa de n?dulos ocorreu nas cultivares Vereda e Estilo, na primeira e segunda coletas, respectivamente, e a cultivar Radiante apresentou a menor massa de n?dulos. O rendimento m?dio de gr?os das oito cultivares foi de 3284 e 3919 kg ha-1 sobinocula??o e N mineral, respectivamente. O ac?mulo de N derivado da FBN nos gr?os foi de 68,4 kg ha-1 na cultivar Ouro Negro, 38,7 kg ha-1 na cultivar Grafite e 21,6 kg ha-1 na cultivar Radiante, que correspondeu a 49, 29 e 32% de contribui??o da FBN, respectivamente. A t?cnica da abund?ncia natural de 15N possibilita a identifica??o do potencial de FBN para o fornecimento de N em diferentes gen?tipos de feijoeiro, e mostra-se como uma ferramenta capaz de fornecer subs?dios para orientar os programas de melhoramento da esp?cie, visando aumentar a efici?ncia da FBN.
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Atividade das enzimas nitrogenase e nitrato redutase em plantas de feijoeiro oriundas de sementes com diferentes teores de molibd?nio. / Activities of nitrogenase and nitrate reductase enzymes in common bean plants originating from seeds with different molybdenum concentrations.Almeida, Fernanda Fatima Delgado de 11 February 2010 (has links)
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Previous issue date: 2010-02-11 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Seeds with high molybdenum (Mo) concentration can provide amounts of the nutrient
highly enough to guarantee an adequate plant growth. An essay and two experiments
were carried out in pots to evaluate the effect of Mo concentration in seeds of common
bean (Phaseolus vulgaris L.) on the assimilation of N from the soil and the biological
N2 fixation (BNF), through measuring the activities of the nitrogenase and nitrate
reductase enzymes and the contribution of the BNF by the 15N isotope dilution, at
different plant growth stages. The substrate was A horizon of Argisol (Hapludult) in 10
kg pots. Seeds of the cultivar Carioca enriched or not with Mo were tested. The essay
had a 2x3 factorial design: two seed Mo concentrations (low and high) and three N
sources (without N, inoculated and mineral N), with two replicates. Plants were
harvested at 42 days after emergence (DAE). High concentration of Mo in seeds
increased shoot dry mass, the nitrate reductase activity and shoot N accumulation, but
reduced nodule number. The experiment 1 had a 2x2x4 factorial design: two seed Mo
concentrations (low and high), two N sources (inoculated and mineral N) and four dates
of harvest (20, 34, 45 and 55 DAE), with five replicates. An extra treatment was
included, with seeds with high Mo concentration, inoculation and Mo added to the soil,
with four harvests. No effect of Mo added to the soil was identified, as compared to the
high seed Mo. High seed Mo increased the leaf area and shoot dry mass at the four
times of harvest, and the pod mass at 55 DAE, at both N sources. Seeds with high Mo
concentration increased the nitrate reductase activity at 45 DAE under mineral N, and
nitrogenase activity at 20 and 45 DAE under inoculation. High Mo seeds increased
shoot N accumulation at both N sources at pod filling stage. The experiment 2 had a
2x2x2 factorial design: two seed Mo concentrations (low and high), two N sources
(inoculated and mineral N) and two dates of harvest (38 and 51 DAE), with five
replicates. The soil was previously fertilized with 15N-enriched urea. Non-nodulating
bean, sunflower and sorghum were used as control plants. At 51 DAE, plants
originating from high Mo seeds had higher shoot mass at both N sources, but lower
nodule number under mineral N. High Mo seed increased nitrate reductase activity at 51
DAE at both N sources, and nitrogenase activity at 38 DAE in inoculated plants. High
Mo seeds increased shoot N accumulation at both N sources. High Mo seeds improved
the contribution of the BNF at the pod filling stage, as estimated by the 15N isotope
dilution technique. It is concluded that common bean seeds enriched with Mo stimulate
the assimilation of N from the soil and the BNF, increasing the accumulation of biomass / Sementes com elevadas concentra??es de molibd?nio (Mo) podem fornecer quantidades
do nutriente suficientes para garantir adequado crescimento ?s plantas. Foram
conduzidos um ensaio e dois experimentos com objetivo de avaliar o efeito do teor de
Mo em sementes de feijoeiro (Phaseolus vulgaris L.) na assimila??o do N do solo e na
fixa??o biol?gica do N2 (FBN), atrav?s da mensura??o das atividades das enzimas
nitrogenase e nitrato redutase, e da contribui??o da FBN pela dilui??o isot?pica de 15N,
em diferentes est?dios de desenvolvimento vegetal. O substrato foi horizonte A de
Argissolo em vasos de 10 kg, utilizando-se sementes da cultivar Carioca enriquecidas
ou n?o com Mo. O ensaio teve arranjo fatorial 2x3: dois teores de Mo na semente (baixo
e alto) e tr?s fontes de N (sem N, inoculado e N mineral), com duas repeti??es e coleta
aos 42 dias ap?s emerg?ncia (DAE). O alto Mo da semente aumentou a atividade da
nitrato redutase, a massa e a acumula??o de N na parte a?rea, mas reduziu o n?mero de
n?dulos. O experimento 1 teve arranjo fatorial 2x2x4: dois teores de Mo na semente
(baixo e alto), duas fontes de N (inoculado e N mineral) e quatro ?pocas de coleta (20,
34, 45 e 55 DAE), com cinco repeti??es. Foi inclu?do um tratamento extra, com
sementes com alto Mo, inocula??o e adi??o de Mo ao solo. N?o foi identificado efeito
do Mo adicionado ao solo quando comparado com o alto Mo na semente. O alto Mo na
semente aumentou a ?rea foliar e a massa de parte a?rea nas quatro ?pocas de coleta, e a
massa de vagem aos 55 DAE, nas duas fontes de N. Sementes com alto Mo aumentaram
a atividade da nitrato redutase aos 45 DAE sob N mineral, e a atividade da nitrogenase
aos 20 e 45 DAE sob inocula??o. Sementes com alto Mo aumentaram a acumula??o de
N na parte a?rea nas duas fontes de N no est?dio de enchimento das vagens. O
experimento 2 teve arranjo fatorial 2x2x2: dois teores de Mo na semente (alto e baixo),
duas fontes de N (inoculado e N mineral) e duas coletas (38 e 51 DAE), com cinco
repeti??es. O solo foi previamente adubado com ur?ia enriquecida com 15N. O feij?o
n?o nodulante, girassol e sorgo serviram como plantas controle. Aos 51 DAE, plantas
oriundas de sementes com alto Mo tiveram maior massa de parte a?rea nas duas fontes
de N, mas menor n?mero de n?dulos sob N mineral. O alto Mo nas sementes aumentou
a atividade da nitrato redutase aos 51 DAE, nas duas fontes de N, e a atividade da
nitrogenase aos 38 DAE nas plantas inoculadas. Sementes com alto Mo aumentaram a
acumula??o de N na parte a?rea nas duas fontes de N. Sementes com alto Mo
aumentaram a contribui??o da FBN no est?dio de forma??o das vagens. Conclui-se que
sementes de feijoeiro enriquecidas com Mo estimulam tanto a assimila??o do N do solo
quanto a FBN, aumentando a acumula??o de biomassa e de N do feijoeiro.
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Efeitos da extrus?o de H+/OH- em plantas de feij?o crescidas com diferentes fontes de nitrog?nio sobre o in?cio da forma??o de n?dulos radiculares. / Effects of extrusion of H+/OH- in bean plants grown with different nitrogen sources on the early formation of root nodulesMacedo, Ricardo Ant?nio Tavares de 29 October 2010 (has links)
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Previous issue date: 2010-10-29 / Bean plants can get nitrogen from soil organic matter, fertilizer or biological fixation of
atmospheric N2 (BNF). However, the biological process in this culture has shown low
efficiency under field conditions. As a result, many farmers do not inoculate the seeds with
efficient strains of rhizobia, being fertilizer the main source of N to this culture. Besides the
absence of inoculation, high doses of N applied to the soil inhibit nodulation and BNF.
However, the reasons for this inhibition are not fully understood, especially because the N is
uptaked as nitrate (NO3
-) and ammonium (NH4
+). Whereas the rhizosphere of plants grown
with nitrate is alkalized and ammonium is acidified, the aim of this study was evaluate the
effect of pH changes in rhizosphere (pHR), caused by the metabolism of these N sources, in
start of nodules formation. The experiments were conducted in growth chamber with average
brightness of 400 lux, photoperiod of 12/12 hours (light/dark) and temperature 25?C ? 2?C.
Plants were grown in pots with sand, soils with low (8%) and medium (25%) clay content and
nutrient solution. In the 1st test (salinity) was found that ammonium had the greatest increase
in electrical conductivity of the sand (EC), obtained with a 60 KgN ha-1 the value of 1.655 mS
cm-1 with ammonium and 1.301 mS cm-1 with nitrate. In the following assay were compared
two contrasting cultivars in capacity of nodulate, which confirmed the high (Ouro Negro) and
low (Rio Tibagi) capability. As among cultivars were not significant differences in the values
of pHR, in others experiments was evaluated Ouro Negro only. In this assay and in others
ammonium was the source of N with more capacity of rhizosphere acidify and inhibit
nodulation. Through regression analysis for each N source, was given the dose of total
inhibition of nodulation (critical level), pHR at this dose and the dose which was 80% of
maximum nodulation (dose of coexistence). In general, was verified the lowest doses of
critical level and coexistence using ammonium than with nitrate.
In the sand test (Ouro Negro sampled 20 DAE) for ammonium and nitrate the doses of
coexistence was 13 and 58 KgN ha-1 and the values of pHR was 3,95 and 5,59, respectively.
In test with different soil types (20 DAE), the dose of coexistence was lower with ammonium
than nitrate, being in soil with lower clay content 18 e 41 KgN ha-1 and soil with higher clay
content 15 e 27 KgN ha-1, respectively. The values of pHR for ammonium and nitrate were
4,69 and 6,08 in soil with lower clay content and 4,23 and 4,63 in soil with higher clay
content, respectively. In this test the neutralizers alleviated acidification of the rhizosphere
and nodulation was optimized. In test with leaf application of N, ammonium also more acidify
the rhizosphere and promoted less nodulation (pHR 4,15 and 14 nodules plant-1) compared to
nitrate (pHR 5,03 and 27 nodules plant-1). In the 6th experiment (20 DAE) the dose of 115
kgVO4 ha-1 allowed that highest dose of ammonium did not make changes in pHR, allowing
also the dose of coexistence of 46 KgN ha-1 for ammonium as source of N. In all tests, the
highest N rates from all sources completely inhibited nodulation, suggesting that these doses
were the occurrence of others inhibiting factors independent of pH and not measured. / O feijoeiro pode adquirir nitrog?nio da mat?ria org?nica do solo, de adubos ou da fixa??o
biol?gica do N2 atmosf?rico (FBN). Entretanto, nesta cultura o processo biol?gico tem
apresentado baixa efici?ncia nas condi??es de campo. Em fun??o disso, muitos produtores
n?o inoculam as sementes com estirpes eficientes de riz?bio, sendo a aduba??o a principal
fonte de N para esta cultura. Al?m da aus?ncia da inocula??o, altas doses de N aplicadas no
solo inibem a nodula??o e a FBN. No entanto, as causas para esta inibi??o n?o s?o totalmente
esclarecidas, especialmente pelo fato do N ser absorvido na forma de nitrato (NO3
-) e am?nio
(NH4
+). Considerando que a rizosfera da planta crescida com nitrato ? alcalinizada e com
am?nio ? acidificada, este trabalho teve o objetivo de avaliar o efeito das altera??es de pH
rizosf?rico (pHR), causadas pelo metabolismo destas fontes de N, no in?cio da forma??o de
n?dulos. Os experimentos foram realizados em c?mara de crescimento com luminosidade
m?dia de 400 Lux, fotoper?odo de 12/12 horas (luz/escuro) e temperatura de 25?C ? 2?C.
As plantas foram crescidas em vasos com areia, solos com baixo (8%) e m?dio (25%) teor de
argila e em solu??o nutritiva. No 1? ensaio (salinidade) foi verificado que o am?nio causou
maior eleva??o da condutividade el?trica da areia (CE), obtendo-se na dose de 60 kgN ha-1 o
valor de 1.655 ?S cm-1 com am?nio e de 1.301 ?S cm-1 com nitrato. No ensaio seguinte foram
comparadas 2 cultivares contrastantes quanto ? capacidade nodular, que confirmaram a alta
(Ouro Negro) e a baixa (Rio Tibagi) capacidade. Como entre as cultivares n?o ocorreram
diferen?as expressivas nos valores de pHR, nos demais experimentos avaliou-se apenas a
Ouro Negro. Neste ensaio e nos demais o am?nio foi a fonte de N que mais acidificou a
rizosfera e inibiu a nodula??o. Atrav?s de an?lises de regress?o para cada fonte de N foi
determinada a dose de inibi??o total da nodula??o (n?vel cr?tico), pHR nesta dose e a dose
onde ocorreu 80% da m?xima nodula??o (dose de conviv?ncia). Em geral, foram observadas
as menores doses de NC e de conviv?ncia com uso do am?nio do que com nitrato.
No ensaio em areia (cv Ouro Negro coletada aos 20 DAE), para am?nio e nitrato as doses de
conviv?ncia foram 13 e 58 kgN ha-1 e os valores de pHR 3,95 e 5,59, respectivamente. No
ensaio em diferentes tipos de solo (20 DAE), a dose de conviv?ncia foi menor com am?nio do
que com nitrato, sendo no solo com menor teor de argila 18 e 41 kgN ha-1 e no solo com
maior teor de argila 15 e 27 kgN ha-1, respectivamente. J? os valores de pHR para am?nio e
nitrato foram 4,69 e 6,08 no solo com menor teor de argila e 4,23 e 4,63 no solo com maior
teor de argila, respectivamente. Neste ensaio os neutralizantes aliviaram a acidifica??o da
rizosfera e otimizaram a nodula??o. No ensaio com aplica??o de N via foliar, o am?nio
tamb?m acidificou a rizosfera e promoveu menor nodula??o (pHR 4,15 e 14 n?dulos planta-1)
em rela??o ao nitrato (pHR 5,03 e 27 n?dulos planta-1). No 6? experimento (20 DAE) a dose
de 115 kgVO4 ha-1 permitiu que na mais alta dose de am?nio o pHR n?o sofresse altera??es,
permitindo tamb?m a dose de conviv?ncia de 46 kgN ha-1 para o am?nio. Em todos os
ensaios, as mais altas doses de N de todas as fontes suprimiram a nodula??o, sugerindo que
nestas doses ocorreram fatores inibidores independentes do pH e n?o mensurados.
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Estudo de associa??o entre bact?rias fixadoras de nitrog?nio e fungos micorr?zicos arbusculares associados a leguminosas do grupo das piptadenias / Study of association between nitrogen-fixing bacteria and arbuscular mycorrhizal fungi associated with legumes from the piptadenias groupOliveira Junior, Joel Quintino de 28 February 2014 (has links)
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Previous issue date: 2014-02-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Leguminosae comprises a wide variety of species that form symbiosis with mycorrhizal fungi (AMF), and mostly with nitrogen fixing bacteria. Within this frame fits the group Pitadenia encompassing genres: Mimosa , Piptadenia , Parapiptadenia , Anadenathera , Pseudopiptadenia , Microlobius , Stryphnodendron and Adenopia , comprising over 500 species, of which most are found in the New World , especially in Brazil . Their habits vary from tree and herbaceous species to thrive in flooded, dry, high altitude grasslands , savanna ecosystems among other areas . Are well known and used in the rehabilitation of degraded soils by their aggressiveness and ability to grow under adverse soil conditions. Results indicate that in some species of this group only nodulated with the presence of mycorrhizal fungi. Legumes use for the realization of these two symbioses very similar molecular mechanisms and some of leguminous species from the subfamily Mimosoideae show atypical and high potential exploration of evolutionary symbiosis between the two skills. The objective of this work is to investigate and confirm this dependence of the presence of arbuscular mycorrhizal fungi for nodulation and nitrogen fixation in species group Piptadenia nodulated by Burkholderia sp . under controlled conditions / A fam?lia Leguminosae compreende um imensa variedade de esp?cies que formam simbiose com fungos micorr?zicos arbusculares (FMAs) e, em sua grande maioria, com bact?rias fixadoras de nitrog?nio. Dentro desse quadro se encaixa o grupo de Pitadenia que engloba os g?neros: Mimosa, Piptadenia, Parapiptadenia, Anadenathera, Pseudopiptadenia, Microlobius, Stryphnodendron e Adenopia, compreendendo mais de 500 esp?cies, sendo que a maioria delas ? encontrada no novo mundo, em especial no Brasil. Seus h?bitos variam desde esp?cies herb?ceas at? arb?reas e se desenvolvem em ?reas alagadas, secas, campos de altitude, cerrado entre outros ecossistemas. S?o bem conhecidas e utilizadas na reabilita??o de solos degradados por sua agressividade e capacidade de se desenvolver nas mais adversas condi??es ed?ficas. Resultados indicam que em algumas esp?cies desse grupo s? nodulariam com a presen?a de fungos micorr?zicos. As leguminosas usam para a realiza??o dessas duas simbioses mecanismos moleculares muito similares e algumas dessas esp?cies de leguminosas nativas da subfam?lia Mimosoideae mostram habilidades at?picas e com alto potencial de explora??o evolucion?ria entre as duas simbioses. O objetivo deste trabalho ? investigar e confirmar essa depend?ncia da presen?a de fungos micorr?zicos arbusculares para a nodula??o e fixa??o biol?gica de nitrog?nio em esp?cies do grupo de Piptadenia noduladas por Burkholderia sp. sob condi??es controladas
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