Ammonium decreases muskmelon root system hydraulic conductivity

Adler, Paul R.; Wilcox, G. E.; Markhart, Albert H.

doi:10.1080/01904169609365207

Cited by 35 publications

(22 citation statements)

References 19 publications

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“…Guo et al (2007a) introduced total nitrogen deprivation as a third treatment and could show that reduced water uptake by NH 4 + -supplied Phaseolus roots was not only due to a lack of nitrate; rather, ammonium itself also had a detrimental effect. These results provided first evidence that the water transport properties of root tissue are affected by the supplied N-form (see also Adler et al 1996).…”

Section: Introductionmentioning

confidence: 82%

A 1H NMR study of water flow in Phaseolus vulgaris L. roots treated with nitrate or ammonium

et al. 2009

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The effect of N nutrition on root xylem (water) flow in Phaseolus vulgaris was studied by using the 1 H NMR flow imaging technique. Plants pre-cultivated on CaSO 4 -solution were transferred to NMR-compatible split-root cuvettes filled with halfstrength nitrate medium (2.5 mM). After 6 days fullstrength (5 mM) nitrate medium was supplied to both compartments (NN treatment), or only to one compartment, whereas the other one was perfused with full-strength (5 mM) ammonium medium (NA treatment). Imaging was performed 7-8 days later. Root growth, xylem flow velocity and xylem pressure (measured with the xylem pressure probe) were largely unaffected by N nutrition. Under NA conditions, volume flow was significantly lower in ammonium-compared to nitrate-fed roots due to a reduced number of functional xylem elements. This was apparently not related to anatomical differences nor to an enhanced number of cavitated vessels in ammonium-fed roots. Vessels in these roots may become dysfunctional by clogging to prevent cavitation.

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Section: Introductionmentioning

confidence: 82%

A 1H NMR study of water flow in Phaseolus vulgaris L. roots treated with nitrate or ammonium

et al. 2009

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“…Following the proposal of Adler et al (1996), we investigated whether aquaporin activity of rice roots is affected by different nitrogen forms (Table 3). The contribution of aquaporins to water transport was estimated by inhibition with HgCl 2 , which provides a rough estimate of the effect of aquaporin on root water uptake (Agre et al 1998;Lu and Neumann 1999).…”

Section: Discussionmentioning

confidence: 99%

Ammonium nutrition increases water absorption in rice seedlings (Oryza sativa L.) under water stress

Gao

Yang

et al. 2009

Plant Soil

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Water stress is a primary limitation on plant growth. In previous studies, it has been found that ammonium enhances the tolerance of rice plants to water stress, but how water is related to nitrogen form and water stress remains unknown. To study the effects of nitrogen form (NH 4 + , NO 3 − , and a mixture of NH 4 + and NO 3 − ) on the growth and water absorption of rice (Oryza sativa L.) seedlings, a hydroponic experiment with water stress, simulated by the addition of polyethylene glycol (PEG, 10% w/v, MW 6000), was conducted in a greenhouse. The results showed that, compared with non-water stress, under water stress, the fresh weight of rice seedlings increased by 14% with NH 4 + nutrition, whereas it had decreased by about 20% with either NO 3 − or mixed nitrogen nutrition. No significant difference was found in the transpiration rate of excised shoots or in xylem exudation of excised roots in NH 4 + supply between the two water situations, whereas xylem flow decreased by 57% and 24% under water stress in NO 3 − and mixed nutrition, and root hydraulic conductivity decreased by 29% and 54% in plants in NH 4 + and NO 3 − nutrition conditions, respectively.Although water absorption ability decreased in both NH 4 + and NO 3 − nutrition, aquaporin activity was higher in NH 4 + than in NO 3 − nutrition, regardless of water stress. We conclude that NH 4 + nutrition can improve water handling in rice seedlings and subsequently enhance their resistance to drought.

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“…A estimativa é que a redução e assimilação do nitrato possam consumir até 25% dos processos associados à fotossíntese e ao transporte de elétrons que ocorre em nível de mitocôndrias (BLOOM et al, 1989). No caso do amônio, esse íon pode concorrer para a redução da fotossíntese líquida (GOYAL et al, 1982); redução na absorção de alguns macronutrientes, notadamente potássio, cálcio e magnésio (GUAZZELLI, 1988); alteração nos balanços osmótico e hormonal das plantas (GERENDÁS et al, 1997), redução do pH da solução do solo (MARSCHNER, 1995) e aumento na resistência ao fluxo de água, que pode induzir situações de estresse hídrico (ADLER et al, 1996). Observa-se nas figuras 2B e 2C que os tratamentos constituídos exclusivamente de nitrato ou amônio também proporcionaram menor número de folhas, e as folhas formadas ficaram menores.…”

Section: Msunclassified

“…Esses resultados atestam que o NO 3 -e, mais efetivamente, o NH 4 + foram mais prejudiciais à expansão do que ao aparecimento das folhas, em semelhança ao que foi observado por RAAB e TERRY (1994). Esse efeito do amônio sobre a expansão foliar tem sido relacionado à alteração negativa provocada no potencial hídrico foliar em função da maior resistência hidráulica das raízes (ADLER et al, 1996), à menor translocação de citocininas das raízes para a parte aérea (WALCH-LIU et al, 2000) e à menor absorção de cátions (RAAB e TERRY, 1995).…”

Section: Msunclassified

Efeito do nitrato e amônio sobre o crescimento e eficiência de utilização do nitrogênio em mandioca

2006

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RESUMODesenvolveu-se o presente estudo visando-se avaliar o efeito da fonte nitrogenada sobre o acúmulo de matéria seca e a absorção, distribuição e utilização de nitrogênio em mandioca. Para a instalação do experimento utilizou-se a variedade Cigana preta, cultivada em solução nutritiva e em vasos com capacidade para 11,0 L. O nível de nitrogênio na solução foi de 12 mol m -3 e os tratamentos consistiram de cinco proporções de NO 3 -:NH 4 + , conforme segue: 12:0, 9:3, 6:6, 3:9 e 0:12 mol m -3 . No encerramento do experimento, que ocorreu 90 dias após o plantio, verificou-se que as menores quantidades de massa seca total foram obtidas para as plantas cultivadas tendo apenas nitrato ou amônio como fonte de nitrogênio. Nesse aspecto, o amônio foi mais prejudicial ao crescimento do que a fonte nítrica. A concentração de NH 4 + livre no tecido vegetal foi maior para as raízes de absorção, seguida pelas folhas e raízes de armazenamento. A eficiência de absorção de nitrogênio foi maior para as plantas cultivadas sob as maiores proporções de NH 4 + . Os resultados evidenciaram que a cultura da mandioca cresce melhor quando ocorrer na solução de crescimento uma mistura de NO 3 -e NH 4 + , principalmente nas proporções de 9:3 e 6:6 mol m -3 .Palavras-chaves: massa seca, área foliar, raízes de armazenamento, relação raiz:parte aérea, eficiência no uso de nitrogênio. ABSTRACT EFFECT OF NITRATE AND AMMONIUM ON GROWTH AND EFFICIENCY OF NITROGEN USE BY CASSAVA PLANTSThis study was carried out to evaluate the effect of nitrogen source on dry mass accumulation and absorption, distribution and also use of nitrogen by cassava plants. Cigana Preta cultivar plants were grown in nutrient solutions set up in 11.0 L containers. Nitrogen concentration in solutions was 12 mol m -3 . Treatments included five combinations of NO 3 -:NH 4 + , that is, 12:0, 9:3, 6:6, 3:9 and 0:12 mol m -3 . Aftert 90 days the dry mass was determined. The lowest total dry mass values were obtained for plants grown with just nitrate or ammonium as nitrogen source. In this sence, ammonium affected growth more than the nitric source. The concentration of free NH 4 + was higher for absorption in roots, followed by leaves and storage roots. The efficiency of nitrogen absorption was higher for plants cultivated under highest proportions of NH 4 + . The results showed that cassava plants grow more when growth solution contains a mixture of NO 3 -and NH 4 + , especially at the proportions of 9:3 and 6:6 mol m -3 .

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Ammonium decreases muskmelon root system hydraulic conductivity

Cited by 35 publications

References 19 publications

A 1H NMR study of water flow in Phaseolus vulgaris L. roots treated with nitrate or ammonium

A 1H NMR study of water flow in Phaseolus vulgaris L. roots treated with nitrate or ammonium

Ammonium nutrition increases water absorption in rice seedlings (Oryza sativa L.) under water stress

Efeito do nitrato e amônio sobre o crescimento e eficiência de utilização do nitrogênio em mandioca

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