Distribuição da assimilação de nitrato e de matéria seca em plantas jovens de café cultivadas em diferentes níveis de nitrogênio

Carelli, Maria; Fahl, Joel Irineu

doi:10.1590/s0006-87051991000100004

Cited by 14 publications

(11 citation statements)

References 20 publications

(9 reference statements)

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“…Furthermore, this could also explain, at least in part, the disagreement in the literature concerning the partitioning of NRA in coffee plants. In this regard, higher NRA was obtained in roots than in leaves when experiments were conducted under low irradiance (Carelli et al, 1991;Queiroz et al, 1993a), and vice-versa under higher irradiances (Carelli et al, 1990a;Da Matta et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

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Partitioning of nitrate reductase activity in Coffea arabica L. and its relation to carbon assimilation under different irradiance regimes

Carelli

Fahl

2006

Braz. J. Plant Physiol.

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The distribution of in vivo nitrate reductase (EC 1.6.6.1) activity (NRA) between leaves and roots was studied in young coffee plants (Coffea arabica L.) grown in pots with watered sand in a glasshouse and irrigated with nutrient solution. The influence of irradiance regimes on the partitioning of NRA, and its relation with CO 2 assimilation, was also evaluated in plants grown under approximately 20, 50 and 100% of full sunlight. Time-course of nitrate accumulation in nitrogenstarved plants showed a similar pattern in leaves and roots after supplying 15 mmol L -1 nitrate, indicating efficient ability of the roots to export nitrate to the shoot. At the same time, NRA was rapidly induced in both tissues. In shoots, NRA partitioning was synchronized among the various leaf pairs. The initial increase in NRA, as each leaf pair emerged, coincided with the optimum NRA values of the next older leaf pair. However, the average shoot NRA remained relatively constant for each sampling date. During the first 23 weeks of vegetative growth, the mean NRA was 32% higher in leaves than in roots. The irradiance regimes influenced the partitioning of NRA between leaves and roots. The NRA leaf /root ratio was 0.72, 1.21 and 1.05, respectively, for plants grown under 20%, 50% and 100% of full sunlight. Leaf NRA was positively correlated with CO 2 assimilation, in response to irradiance regimes. Under favorable CO 2 assimilation conditions, higher NRA was observed in leaves than in roots, and the contrary trend occurred under limiting CO 2 assimilation conditions. Under moderate irradiance regime the leaves were the main site of nitrate reduction, contributing with 70% of the whole plant nitrate assimilation. Key words: coffee, growth, leaf/root ratio, nitrate assimilation, photosynthesis, shading Partição da atividade da redutase de nitrato em Coffea arabica L. e sua relação com a assimilação do carbono em diferentes níveis de irradiância: Estudou-se a distribuição da atividade da redutase de nitrato (ARN) in vivo entre folhas e raízes de plantas jovens de café (Coffea arabica L.) cultivadas em vasos contendo areia lavada, em casa de vegetação, e irrigadas com solução nutritiva. Também foi avaliada a influência de regimes de irradiância na partição da ARN e na assimilação do CO 2 , em plantas cultivadas aproximadamente sob 20, 50 e 100% da luz solar. Após o fornecimento de 15 mmol L -1 nitrato, para plantas deficientes em nitrogênio, o acúmulo de nitrato nas folhas e raízes apresentou padrão semelhante, indicando capacidade eficiente das raízes em exportar nitrato para a parte aérea. Ao mesmo tempo, ARN foi rapidamente induzida nos dois tecidos. Na parte aérea, houve um sincronismo na partição da ARN entre os diversos pares de folhas. O aumento da ARN, quando cada par de folhas emerge, coincidiu com as maiores ARN no par de folhas imediatamente mais velho. Contudo, a média da ARN na parte aérea permaneceu relativamente constante, para cada data de amostragem. Durante as primeiras 25 semanas de crescimento vegetativo, a ARN média foi ...

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Section: Discussionmentioning

confidence: 99%

“…Nevertheless, this is a contentious matter, e.g. some reports have shown higher NRA in leaves (Carelli et al, 1990a;Da Matta et al, 1999), whereas others in roots (Carelli and Fahl, 1991;Queiroz et al, 1993a). Such variations in NRA leaf /root ratio are probably due to differences in plant growth stage and environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Partitioning of nitrate reductase activity in Coffea arabica L. and its relation to carbon assimilation under different irradiance regimes

Carelli

Fahl

2006

Braz. J. Plant Physiol.

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“…Nevertheless, there is a lot of controversy about this subject in the literature. Some reports have shown higher NRA in leaves (Carelli et al, 1990a;Da Matta et al, 1999;Amaral et al, 2001), and others in roots (Carelli and Fahl, 1991, Queiroz et al, 1991, 1993a.…”

Section: Partitioning Of Nra Between Leaves and Rootsmentioning

confidence: 94%

“…These findings could explain, at least in part, the contrasting data in the literature concerning the partitioning of NRA in coffee plants. In this sense, higher NRA was obtained in roots than leaves when experiments were conducted under low irradiance (Carelli et al, 1991;Queiroz et al, 1991Queiroz et al, ,1993aCarelli and Fahl, 2005), and vice-versa under higher irradiances (Carelli et al, 1990a;Da Matta et al 1999, Amaral et al 2001Carelli and Fahl, 2005).…”

Section: Partitioning Of Nra Between Leaves and Rootsmentioning

confidence: 99%

“…In coffee plants root growth and nitrate assimilation might compete for the available carbohydrates (Carelli and Fahl, 1991). In addition, the increase in external nitrate concentration induced larger increases in root NRA than leaf NRA (Carelli and Fahl, 1991), hence, causing a strong depletion of sugar content in the roots. In consequence, increasing nitrate availability for young coffee plants resulted in higher shoot/root biomass ratio (Carelli and Fahl, 1991).…”

Section: Physiologycal Significance Of Root Nitrate Assimilationmentioning

confidence: 99%

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Aspects of nitrogen metabolism in coffee plants

Carelli

Fahl

Ramalho

2006

Braz. J. Plant Physiol.

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Coffee plants are highly N-demanding plants. Despite the importance of N nutrition for the development, acclimation and yield of coffee plants, there are few reports concerning N metabolism in this species. In this review, our intention is to summarize the information available in the literature and to point out the influence of environmental conditions on N assimilation, as well as comment and discuss some apparently contradictory results and raise and enlighten queries about N assimilation in coffee plants. Key words: Coffea, irradiance level, nitrate reductase, nitrogen fertilization, oxidative stress, photoinhbition, photoprotection, photosynthesis.Aspectos do metabolismo de nitrogênio em plantas de café: Plantas de cafédemandam grandes quantidades de N. Apesar da importância da nutrição nitrogenada para o desenvolvimento, aclimatação e produtividade de plantas de café, são poucos os trabalhos sobre o metabolismo de N nesta espécie. A intensão desta revisão é sumarizar a informação disponível na literatura e discutir a influência das condições ambientais na assimilação de N, assim como comentar e discutir alguns resultados aparentemente contraditórios e levantar e destacar perguntas sobre a assimilação de N em plantas de café. Palavras-chave: Coffea, estresse oxidativo, fertilização nitrogenada, fotoinibição, fotoproteção, fotossíntese, nível de irradiância, redutase do nitrato.Abbreviations -A, net photosynthetic rate; A max , photosynthetic capacity at CO 2 and light saturating conditions; C16:0, palmitic acid; C18:3, linolenic acid; 3 Car triplet state of β-carotene; chl, chlorophyll; 1 chl, singlet state of chl; 3 chl*, triplet state of chl; cyt, cytochrome; DEPS, de-epoxidation state; F o , minimal fluorescence of antennae in dark-adapted leaves; F v /F m and F v´/ F m´, photochemical efficiency of PSII in dark-adapted leaves and under photosynthetic steadystate conditions, respectively; H 2 O 2 , hydrogen peroxide; LHC, light harvesting complexes associated with photosystems; J max , electron transport capacity; NR, nitrate reductase; NRA, nitrate reductase activity; O 2•-, superoxide anion radical; 1 O 2 , singlet state of oxygen; OEC, oxygen-evolving complex from PSII; • OH, hydroxyl radical; P 680 , PSII reaction centre; PPFD, photosynthetic photon flux density; PSI and II, photosystem I and II, respectively; Q A , quinone A; q E , "high-energy" quenching; q NP , non-photochemical quenching; q P , photochemical quenching; TFA, total fatty acids; V cmax , maximum carboxylation activity; Φ, quantum yield of photosynthesis; φ e , estimation of the quantum yield of photosynthetic electron transport.

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Low-Temperature Stress and Nitrogen Metabolism in Plants: A Review

Bhattacharya

2022

Physiological Processes in Plants Under Low Temperature Stress

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Distribuição da assimilação de nitrato e de matéria seca em plantas jovens de café cultivadas em diferentes níveis de nitrogênio

Cited by 14 publications

References 20 publications

Partitioning of nitrate reductase activity in Coffea arabica L. and its relation to carbon assimilation under different irradiance regimes

Partitioning of nitrate reductase activity in Coffea arabica L. and its relation to carbon assimilation under different irradiance regimes

Aspects of nitrogen metabolism in coffee plants

Low-Temperature Stress and Nitrogen Metabolism in Plants: A Review

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