Maintenance of Photosynthesis at Low Leaf Water Potential in Wheat

Gupta, Apoorva; Berkowitz, Gerald A.; Pier, P.A.

doi:10.1104/pp.89.4.1358

Cited by 102 publications

(53 citation statements)

References 23 publications

(36 reference statements)

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“…relataram que alterações metabólicas na planta ocorrem antes das alterações do estado hídrico. Em estudo realizado em trigo, Sen Gupta et al (1989) demonstraram que, apesar de ter ocorrido resposta positiva da adubação potássica em condição de estresse hídrico em plantas expostas a dois ciclos de restrição hídrica, a interferência deste nutriente na fotossíntese foi muito menos pronunciada neste caso do que quando as plantas foram sujeitas a um único e curto ciclo de restrição hídrica.…”

Section: Resultsunclassified

Respostas fisiológicas de cultivares de soja à adubação potássica sob diferentes regimes hídricos

Catuchi

Guidorizzi

Guidorizi

et al. 2012

Pesq. agropec. bras.

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Resumo -O objetivo deste trabalho foi avaliar a interferência da adubação potássica em parâmetros fisiológicos de duas cultivares de soja, sob diferentes regimes hídricos. O experimento foi realizado em condições de casa de vegetação, em Presidente Prudente, SP. Utilizou-se o delineamento experimental inteiramente casualizado, em arranjo fatorial 2x2x3, com as cultivares BR-16 (tolerante ao estresse hídrico) e Embrapa 48 (suscetível), regimes hídricos com reposição diária de água de 100% (controle) e de 40% da capacidade de campo, e três níveis de suplementação com K (0, 90 e 180 mg dm -3). Duas semanas após a imposição da restrição hídrica, foram avaliados: conteúdo relativo de água, potencial fotossintético e rendimento de biomassa. As plantas que se desenvolveram sob restrição hídrica tiveram sua capacidade fotossintética reavaliada após 12 horas de reidratação. Em condições de restrição hídrica, a adubação potássica não interferiu significativamente nos parâmetros fisiológicos e de crescimento avaliados. A suplementação com potássio promoveu melhor eficiência dos parâmetros fisiológicos, no regime sem deficiência hídrica, nas duas cultivares, e as principais variáveis influenciadas pelo nutriente foram: condutância estomática, taxa máxima de carboxilação da Rubisco e assimilação máxima de CO 2 . A suplementação com K melhora a recuperação fotossintética das plantas após a reidratação, especialmente na cultivar Embrapa 48.Termos para indexação: Glycine max, biomassa, deficit hídrico, fotossíntese, nutrição. Physiological responses of soybean cultivars to potassium fertilization under different water regimesAbstract -The objective of this work was to evaluate the interference of potassium fertilization on the physiological parameters of soybean cultivars under different water regimes. The experiment was carried out in greenhouse at Presidente Prudente, SP, Brazil. The experimental design was a completely randomized block in a 2x2x3 factorial arrangement, with the soybean cultivars BR-16 (tolerante ...) and Embrapa 48 (suscept...), water regimes with daily replacements of 100% (control) and 40% of the field capacity, and three levels of K supplementation (0, 90, and 180 mg dm -3). Relative water content, photosynthetic potential, and biomass yield were evaluated two weeks after the initiation of water restriction. Plants grown under water restriction had their photosynthetic potential reevaluated after 12 h of rehydration. Under water restriction conditions, potassium fertilization did not significantly affect the assessed growth and physiological parameters. Supplementation with potassium promoted a better efficiency of the physiological parameters, in water deficit control, in both cultivars, and the main variables influenced by the nutrient were: stomatal conductance, maximum rate of Rubisco carboxylation, and maximum CO 2 assimilation. Potassium supplementation improves photosynthetic recovery of plants after rehydration, especially in the Embrapa 48 cultivar.Index terms: Glycine max, biomass, water deficit...

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Section: Resultsunclassified

Respostas fisiológicas de cultivares de soja à adubação potássica sob diferentes regimes hídricos

Catuchi

Guidorizzi

Guidorizi

et al. 2012

Pesq. agropec. bras.

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“…One adaptive physiological mechanism allowing for enhanced plant survival during periods of soil water deficits is leaf osmotic adjustment (31,(33)(34)(35). In prior work with Arabidopsisoverexpressing AVP1, greater solute accumulation in leaves was identified as one basis for altered response to water deficit (17).…”

Section: Resultsmentioning

confidence: 99%

Up-regulation of a H ⁺ -pyrophosphatase (H ⁺ -PPase) as a strategy to engineer drought-resistant crop plants

Park

Pittman

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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170

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Engineering drought -resistant crop plants is a critically important objective. Overexpression of the vacuolar H ؉ -pyrophosphatase (H ؉ -PPase) AVP1 in the model plant Arabidopsis thaliana results in enhanced performance under soil water deficits. Recent work demonstrates that AVP1 plays an important role in root development through the facilitation of auxin fluxes. With the objective of improving crop performance, we expressed AVP1 in a commercial cultivar of tomato. This approach resulted in (i) greater pyrophosphate-driven cation transport into root vacuolar fractions, (ii) increased root biomass, and (iii) enhanced recovery of plants from an episode of soil water deficit stress. More robust root systems allowed transgenic tomato plants to take up greater amounts of water during the imposed water deficit stress, resulting in a more favorable plant water status and less injury. This study documents a general strategy for improving drought resistance of crops.root development ͉ biotechnology ͉ water deficit stress ͉ tomato

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“…With further declines in leaf '', protoplast volume reduction is more pronounced; at -1.8 MPa, protoplast volume is reduced by 50%. The results of previous work in this laboratory (3,19,20) and others (1 1) have led to the speculation that dual label infiltration measurements of the protoplast volume/*,,, relationship in leaves may be a convenient screening procedure to access the extent of water deficit inhibition of chloroplast metabolism in leaves, and also differences in cellular-level acclimation to low I'. (Fig.…”

Section: Comparison Of P/v Curve and Dual Label Infiltration Analysismentioning

confidence: 99%

“…This technique involves the vacuum infiltration of solutions (at a range of 'Is) containing radiolabeled H20 and sorbitol into leaf tissue. The difference between the 3H20-space (total volume) and [ (2,12,17,20). However, in many studies (e.g.…”

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confidence: 99%

Protoplast Volume:Water Potential Relationship and Bound Water Fraction in Spinach Leaves

Santakumari¹,

Berkowitz²

1989

Plant Physiol.

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Methods used to estimate the (nonosmotic) bound water fraction (BWF) (i.e. apoplast water) of spinach (Spinacia oleracea L.) leaves were evaluated. Studies using three different methods of pressure/volume (P/V) curve construction all resulted in a similar calculation of BWF; approximately 40%. The theoretically derived BWF, and the water potential (I,)/relative water content relationship established from P/V curves were used to establish the relationship between protoplast (i.e. symplast) volume and *w.Another method of establishing the protoplast volume/Iw relationship in spinach leaves was compared with the results from P/V curve experiments. This second technique involved the vacuum infiltration of solutions at a range of osmotic potentials into discs cut from spinach leaves. These solutions contained radioactively labeled H20 and sorbitol. This dual label infiltration technique allowed for simultaneous measurement of the total and apoplast volumes in leaf tissue; the difference yielded the protoplast volume. The dual label infiltration experiments and the P/ V curve constructions both showed that below -1 megapascals, protoplast volume decreases sharply with decreasing water potential; with 50% reduction in protoplast volume occurring at -1.8 megapascals leaf water potential.Recent studies (3,19) have indicated that in leaves of plants exposed to water deficits, loss of photosynthetic capacity by chloroplasts may be more closely related to the extent of protoplast and/or chloroplast volume reduction than the low tp2 induced in dehydrated cells. The measurement of protoplast (i.e. symplast) volume changes in leaves of plants subjected to water deficits may be, therefore, an important indicator of physiological competence of cells in water stressed leaves.Direct measurement of the volume/*,' relationship in conjunction with photosynthesis studies has delineated clear differences between cultivars of an agronomic crop with regards to stress resistance (i.e. maintenance of photosynthetic capac-

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Maintenance of Photosynthesis at Low Leaf Water Potential in Wheat

Cited by 102 publications

References 23 publications

Respostas fisiológicas de cultivares de soja à adubação potássica sob diferentes regimes hídricos

Respostas fisiológicas de cultivares de soja à adubação potássica sob diferentes regimes hídricos

Up-regulation of a H ⁺ -pyrophosphatase (H ⁺ -PPase) as a strategy to engineer drought-resistant crop plants

Protoplast Volume:Water Potential Relationship and Bound Water Fraction in Spinach Leaves

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Maintenance of Photosynthesis at Low Leaf Water Potential in Wheat

Cited by 102 publications

References 23 publications

Respostas fisiológicas de cultivares de soja à adubação potássica sob diferentes regimes hídricos

Respostas fisiológicas de cultivares de soja à adubação potássica sob diferentes regimes hídricos

Up-regulation of a H + -pyrophosphatase (H + -PPase) as a strategy to engineer drought-resistant crop plants

Protoplast Volume:Water Potential Relationship and Bound Water Fraction in Spinach Leaves

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Up-regulation of a H ⁺ -pyrophosphatase (H ⁺ -PPase) as a strategy to engineer drought-resistant crop plants