In vivo NMR Studies of Higher Plants and Algae

Ratcliffe, George

doi:10.1016/s0065-2296(08)60215-3

Cited by 90 publications

(51 citation statements)

References 231 publications

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“…1). The 31 P NMR spectra of the maize root segments showed the expected features for a highly vacuolated tissue (Gerendás et al, 1990;Ratcliffe, 1994), with a dominant signal from the vacuolar inorganic phosphate (P i ) pool as well as weaker signals from a range of cytoplasmic metabolites (Fig. 1A).…”

Section: Improved Cytoplasmic Ph Regulation In the Presence Of Nitratementioning

confidence: 75%

Nitrite Reduces Cytoplasmic Acidosis under Anoxia

et al. 2006

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The ameliorating effect of nitrate on the acidification of the cytoplasm during short-term anoxia was investigated in maize (Zea mays) root segments. Seedlings were grown in the presence or absence of nitrate, and changes in the cytoplasmic and vacuolar pH in response to the imposition of anoxia were measured by in vivo 31 P nuclear magnetic resonance spectroscopy. Soluble ions and metabolites released to the suspending medium by the anoxic root segments were measured by high-performance liquid chromatography and 1 H nuclear magnetic resonance spectroscopy, and volatile metabolites were measured by gas chromatography and gas chromatography-mass spectrometry. The beneficial effect of nitrate on cytoplasmic pH regulation under anoxia occurred despite limited metabolism of nitrate under anoxia, and modest effects on the ions and metabolites, including fermentation end products, released from the anoxic root segments. Interestingly, exposing roots grown and treated in the absence of nitrate to micromolar levels of nitrite during anoxia had a beneficial effect on the cytoplasmic pH that was comparable to the effect observed for roots grown and treated in the presence of nitrate. It is argued that nitrate itself is not directly responsible for improved pH regulation under anoxia, contrary to the usual assumption, and that nitrite rather than nitrate should be the focus for further work on the beneficial effect of nitrate on flooding tolerance.

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Section: Improved Cytoplasmic Ph Regulation In the Presence Of Nitratementioning

confidence: 75%

Nitrite Reduces Cytoplasmic Acidosis under Anoxia

et al. 2006

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“…In our experiment, growth independent P consumption was observed in the P free-access treatments. This can be attributed to the accumulation of inorganic phosphorus (Pi) in the vacuole [32,46] and to a higher concentration of P incorporated in organic compounds in the cell as polyphosphate or phytate [13]. This ability may be ecologically important in enabling plants to face seasonal variations in phosphorus availability observed in the field [10].…”

Section: Discussionmentioning

confidence: 99%

Interactive effects of phosphorus and light availability on early growth of maritime pine seedlings

Cheaib¹,

Mollier²,

Thunot³

et al. 2005

Ann. For. Sci.

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-We examined the response of early growth of maritime pine seedlings to combined levels of light and phosphorus. Seedlings were grown under three levels of phosphorous availability, i.e., two relative addition rates (RAR = 2 and 4 g P (100 g -1 )P d -1 ) and a free-access to P, crossed with two light levels (photosynthetic photon flux densities of 150 and 450 µmol m -2 s -1 , respectively). Relative growth rate (RGR) and relative uptake rate of phosphorus (RUR) were computed, as well as the amount of light absorbed per seedling. We found that phosphorus and light acted as limiting factors with a complex interaction. Under low light and at the lowest P level, P and light were co-limiting, i.e., growth was enhanced only when P and light were increased together. Light was the limiting factor for growth under low light conditions at all other levels of P availability. P was the limiting factor at a RAR of 2% under high light. Enhancing P from 4% to free access did not significantly improve growth under high light. RUR was controlled systematically by P availability at 2 and 4% RAR. RGR values were close to RUR values except under free access to P. Therefore, growth-independent accumulation of P was observed under high P conditions. The differences in biomass production among P treatments were explained primarily by the reduced amount of radiation intercepted by the seedlings as a consequence of their reduced leaf area. No effect of P treatments were observed on the calculated radiation-use efficiency (RUE), which was found to be larger under low light. This confirms that pine seedlings adjust to moderate phosphorus deficiency mainly by changing their morphology (leaf area, dry-mass partitioning) while biochemical and photochemical limitations of photosynthesis play only a very secondary role.phosphorus nutrition / shade / growth / Pinus pinaster Aït.Résumé -Interaction des effets de la disponibilité en phosphore et en lumière sur la croissance de jeunes plants de pin maritime. La croissance de jeunes plants de pin maritime a été suivie en chambre de culture à deux niveaux d'éclairement et trois de disponibilité en phosphore. Deux taux d'addition relatifs en P (RAR = 2 et 4 g P (100 g -1 P j -1 ) et un libre accès au P ont été appliqués en combinaison avec deux niveaux d'éclairement (150 et 450 µmol m -2 s -1 ). Le taux de croissance relatif (RGR) et le taux d'absorption relatif de P (RUR) ont été calculés. La surface foliaire, la quantité de rayonnement absorbé et l'efficience d'utilisation du rayonnement (RUE) ont aussi été estimés. Les disponibilités en phosphore et en lumière ont limité la croissance suivant un schéma d'interaction complexe. Au plus faible niveau d'éclairement et d'ajout en phosphore, les deux facteurs étaient co-limitants et la croissance n'était augmentée que lorsque les deux facteurs augmentaient simultanément. La lumière était le facteur limitant pour les traitements sous faible éclairement à tous les autres niveaux de disponibilité en P. Le phosphore était limitant pour des RAR de 2...

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“…To test this, we used in vivo $"P nuclear magnetic resonance (NMR) spectroscopy to measure pH cyt and pH vac in the submerged leaves and roots of C. intrepidus. This technique provides a non-destructive method for estimating subcellular pH values on the basis of the pH dependence of the chemical shift of the ubiquitous $"P NMR signal from inorganic phosphate (P i ), and it has been used extensively for this purpose in plant tissues (Ratcliffe, 1994 and references therein).…”

Section: mentioning

confidence: 99%

Intracellular pH stability in the aquatic resurrection plant Chamaegigas intrepidus in the extreme environmental conditions that characterize its natural habitat

1998

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Chamaegigas intrepidus Dinter (syn. Lindernia intrepidus (Dinter) Oberm.) is a poikilohydric aquatic plant that lives in rock pools on granitic outcrops in Central Namibia. The pools are only filled intermittently during the summer rains, and the plants can pass through 15–20 rehydration/dehydration cycles during a single wet season. Rehydrated plants also have to cope with substantial diurnal fluctuations in the pool pH as a result of photosynthetic CO2 uptake. We have used in vivo31P NMR spectroscopy to investigate the effect of external pH and dehydration (low water potential) on intracellular pH in the roots and submerged leaves of C. intrepidus. Increasing the external pH from 6 to 10 had no effect on the steady state cytoplasmic and vacuolar pH values of submerged leaves, but caused a slight alkalinization of the root cytoplasm. Similarly dehydration with PEG‐600 at either pH 6 or pH 10 had no effect on the cytoplasmic pH of the leaves, but it did cause a small alkalinization of the leaf vacuoles at pH 10. These results imply an unusually effective regulation of intracellular pH, consistent with the adaptation of C. intrepidus to the extreme environmental conditions of its habitat. The NMR analysis also showed that dehydration had no effect on the inorganic phosphate and phosphocholine pools, and this was taken to indicate that the cell membranes were well protected from the effects of the low water potential.

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In vivo NMR Studies of Higher Plants and Algae

Cited by 90 publications

References 231 publications

Nitrite Reduces Cytoplasmic Acidosis under Anoxia

Nitrite Reduces Cytoplasmic Acidosis under Anoxia

Interactive effects of phosphorus and light availability on early growth of maritime pine seedlings

Intracellular pH stability in the aquatic resurrection plant Chamaegigas intrepidus in the extreme environmental conditions that characterize its natural habitat

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