The Intracellular Distribution of Some Metallic Elements in Leaves

Stocking, C. R.; Ongun, Alpaslan

doi:10.1002/j.1537-2197.1962.tb14939.x

Cited by 81 publications

(41 citation statements)

References 12 publications

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“…This was verified in this experiment, where the SPAD readings and leaf N concentrations were significantly lower in the treatment without N. This relationship was mainly attributed to the fact that 50-70 % of the total leaf N is integrated in enzymes (Chapman & Barreto, 1997), associated to chloroplasts (Stoking & Ongun, 1962), responsible for the green leaf color. Orioli (2008) Orioli (2008) and those in our experiment were below the threshold considered satisfactory by Argenta et al (2002), who determined a SPAD threshold of 58 for leaves at flowering as critical.…”

Section: Resultssupporting

confidence: 77%

Ammonia volatilization and yield components after application of polymer-coated urea to maize

Zavaschi¹,

Faria

Vitti

et al. 2014

Rev. Bras. Ciênc. Solo

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SUMMARYA form of increasing the efficiency of N fertilizer is by coating urea with polymers to reduce ammonia volatilization. The aim of this study was to evaluate the effect of polymer-coated urea on the control of ammonia volatilization, yield and nutritional characteristics of maize. The experiment was carried out during one maize growing cycle in 2009/10 on a Geric Ferralsol, inUberlândia, MG, Brazil. Nitrogen fertilizers were applied as topdressing on the soil surface in the following urea treatments: polymer-coated urea at rates of 45, 67.5 and 90 kg ha -1 N and one control treatment (no N), in randomized blocks with four replications. Nitrogen application had a favorable effect on N concentrations in leaves and grains, Soil Plant Analysis Development (SPAD) chlorophyll meter readings and on grain yield, where as coated urea had no effect on the volatilization rates, SPAD readings and N leaf and grain concentration, nor on grain yield in comparison to conventional fertilization.Index terms: nitrogen, polymer-coated urea, N fertilizer, ammonia volatilization, Zea mays, SPAD reading.( Uma das maneiras de aumentar a eficiência dos fertilizantes nitrogenados, visando, por exemplo, à redução de perdas de amônia por volatilização, é o revestimento desses com polímeros. Objetivou-se avaliar o efeito da aplicação de ureia revestida com polímeros no controle da volatilização de amônia e a sua influência nos componentes da produção na cultura do milho. O experimento foi instalado na safra 2009/10 no município de Uberlândia, MG, em um Latossolo Vermelho-Amarelo (LVA) distrófico textura argilosa. Os tratamentos consistiram na aplicação, em cobertura no milho, de ureia revestida com polímeros e ureia convencional nas doses de 45; 67,5; e 90 kg ha -1 de N, mais um tratamento-controle (sem N), dispostos em blocos casualizados. A aplicação de N influenciou positivamente o teor do nutriente nas folhas e nos grãos, a leitura SPAD e a produtividade de grãos, porém a ureia revestida não alterou as taxas de volatilização de amônia, a leitura SPAD e o teor de N nas folhas e grãos, assim como a produtividade de grãos em relação à aplicação do fertilizante convencional.Termos de indexação: nitrogênio, ureia revestida com polímeros, fertilizante nitrogenado, volatilização de amônia, Zea mays, leitura SPAD.

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Section: Resultssupporting

confidence: 77%

Ammonia volatilization and yield components after application of polymer-coated urea to maize

Zavaschi¹,

Faria

Vitti

et al. 2014

Rev. Bras. Ciênc. Solo

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“…If most of the Mg2" had been limited to the cytoplasm, it could have provided sufficient osmotic potential to prevent water stress in the cytoplasm. Only 10% of the magnesium in leaftissue is bound in Chl (25), leaving most of the magnesium as free ions or in a labile, readily dissociable state, which could account for the rapid increase in free Mg2+, presumably as a shock response. The concentration of Mg2" in the leaf tissue, in excess of 100 mm, was high when compared to that of glycophytes, which are usually considerably less than 50 mm.…”

Section: Resultsmentioning

confidence: 99%

Rapid Osmotic Adjustment by a Succulent Halophyte to Saline Shock

Mcnulty¹

1985

Plant Physiol.

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The objective of this research was to measure the short term osmotic adjustment of Saticornia europaea L. ssp. rubra (A. Nels) Breitung when suddenly exposed to 100 millimolar NaCl. Plants were grown hydroponically, shocked with 100 millimolar NaCI added to the culture solution, and stem tips analyzed for free inorganic ions and small organic molecules at intervals up to 72 hours. In the first 2 hours, the calculated leaf osmoticum showed a net increase of 158.8 millimolar most (16,18,20,28,32). Compartmentation of extraneous ions in the vacuole would necessitate an equal amount of compatible solutes in the cytoplasm to balance the water potential. Small organic molecules that could act alone as osmotica in the cytoplasm without disruption of metabolic reactions have been reported (4,10,21,24,26,27 possible mechanism for cytoplasmic osmotic adjustment is a general increase in osmotica as suggested by Greenway and Sims (15) or an increase in two or more organic solutes together (10, 24).The experimental design used by most investigators of salt tolerance mechanisms in terrestrial halophytes has been to grow them in ranges of salinity, followed by analyses of potential osmotica. There is little experimental evidence for the changes that occur in the leaves of halophytes when subject to salinity shock, i.e. a sudden increase in exogenous salt concentration (13). The objective of this study was to investigate the short term osmotic adjustment by a succulent, C3, salt-accumulating halophyte when subjected to a saline shock, measuring the degree of osmotic adjustment achieved, and ascertaining which solutes might be responsible. MATERIALS AND METHODSSeeds of Salicornia europaea L. ssp. rubra (A. Nels.) Breitung were collected locally and germinated in vermiculite wet with Hoagland solution. When about 2 cm high, the seedlings were transferred to large hydroponic tanks containing Hoagland solution plus 10 mM NaCl. The tanks were continuously aerated and the culture solution was changed at 2-week intervals. Sixty d after transplanting, the plants were still vegetative, profusely branched, and about 30 cm tall. At this time (time 0), 4 h after sunrise, 1-to 2-cm samples were taken from the terminal ends of the succulent stems. NaCl was then added to the culture solution to bring it to 100 mm NaCl, and samples were again taken at 2,4,6,8,12,16,20,24, 48, and 72 h after the addition of salt. Sampling was terminated at 72 h, because previous experiments indicated that 96% of the osmotic adjustment had occurred by this time, complete adjustment required 195 h. The samples were all taken from the terminal ends of the stems to insure similar ages and stages ofdevelopment ofthe tissues. They were rapidly rinsed in distilled H20, damp dried, sealed in bottles, and frozen in liquid N2.Extraction and Analysis. Osmotic potential of the terminal shoots was measured cryoscopically with an osmometer. Pressure extraction of the frozen and thawed shoots did not provide satisfactory reproducible results, so the following proce...

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“…Stocking and Ongun (21) reported use of a nonaqueous medium in the isolation procedure that yields chloroplasts with a much higher metal content than those obtained by using an aqueous medium. The use of nonaqueous media in the technique described herein for studying subcellular localization of essential nutrient metals should be informative.…”

Section: Discussionmentioning

confidence: 99%

Subcellular Localization of Zinc and Calcium in Bean (Phaseolus vulgaris L.) Tissues

1972

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Two bean (Phaseolus vulgaris L.) cultivars differing in growth responses to zinc were examined for differences in uptake and subcellular localization of 0Zn during a 15-day growth period. The zinc-sensitive cultivar Sanilac showed initially a much higher rate of absorption, which declined after 24 hours. The zinc-tolerant cultivar Saginaw showed a slow but steady rate of absorption for 10 days. In roots as well as in stem callus tissues of both cultivars, three-fourths of the absorbed "5Zn was localized in the "cytoplasmic" supernatant fractions (containing ribosomes and vacuolar sap). Very little (less than 7%) "Zn was localized in the cell wall fraction. There was a much greater proportion of the absorbed "Zn localized in root mitochondria and nuclei of the zinc-sensitive Sanilac than in the zinc-tolerant Saginaw. Stem The intracellular localization of enzymes in plant tissues has received wide attention (2,4,6,8,11,15,16,18,20

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The Intracellular Distribution of Some Metallic Elements in Leaves

Cited by 81 publications

References 12 publications

Ammonia volatilization and yield components after application of polymer-coated urea to maize

Ammonia volatilization and yield components after application of polymer-coated urea to maize

Rapid Osmotic Adjustment by a Succulent Halophyte to Saline Shock

Subcellular Localization of Zinc and Calcium in Bean (Phaseolus vulgaris L.) Tissues

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