Effect of Soil-Moisture Content on the Rate of Photosynthesis and Respiration in Ladino Clover (Trifolium Repens L.).

Upchurch, R. P.; Peterson, M. L.; Hagan, Robert M.

doi:10.1104/pp.30.4.297

Cited by 30 publications

(12 citation statements)

References 4 publications

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“…Nevertheless, this observation agrees with some published studies in other species (Lawlor, 1976;Loboda, 1993;Flexas et al, 2005). However, several other authors have found different results on the effect of water stress on respiration, ranging from decrease (Brix, 1962;Brown and Thomas, 1980;Palta and Nobel, 1989;Escalona et al, 1999;Ghashghaie et al, 2001;Haupt-Herting et al, 2001) to stimulation (Upchurch et al, 1955;Shearmann et al, 1972;Zagdań ska, 1995). In all cases, as in this study, changes in respiration were much less than those in photosynthesis, causing a significant increase in the respiration/photosynthesis ratio under water stress, indicating that the role of respiration becomes more important as water stress develops.…”

Section: The Effect Of Water Stress On Leaf Respirationcontrasting

confidence: 53%

Effects of Water Stress on Respiration in Soybean Leaves

et al. 2005

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The effect of water stress on respiration and mitochondrial electron transport has been studied in soybean (Glycine max) leaves, using the oxygen-isotope-fractionation technique. Treatments with three levels of water stress were applied by irrigation to replace 100%, 50%, and 0% of daily water use by transpiration. The levels of water stress were characterized in terms of lightsaturated stomatal conductance (g s ): well irrigated (g s . . Although net photosynthesis decreased by 40% and 70% under mild and severe water stress, respectively, the total respiratory oxygen uptake (V t ) was not significantly different at any water-stress level. However, severe water stress caused a significant shift of electrons from the cytochrome to the alternative pathway. The electron partitioning through the alternative pathway increased from 10% to 12% under well-watered or mild water-stress conditions to near 40% under severe water stress. Consequently, the calculated rate of mitochondrial ATP synthesis decreased by 32% under severe water stress. Unlike many other stresses, water stress did not affect the levels of mitochondrial alternative oxidase protein. This suggests a biochemical regulation (other than protein synthesis) that causes this mitochondrial electron shift.Water stress is considered one of the most important factors limiting plant performance and yield worldwide (Boyer, 1982). Effects of water stress on a plant's physiology, including growth (McDonald and Davies, 1996), signaling pathways (Chaves et al., 2003), gene expression (Bray, 1997(Bray, , 2002, and leaf photosynthesis (Lawlor and Cornic, 2002;Flexas et al., 2004), have been studied extensively. Surprisingly, compared with other physiological processes, studies examining the effects of water stress on respiration are few (Hsiao, 1973; Amthor, 1989), despite the importance of respiration in ecosystem annual net productivity (Valentini et al., 1999) and the fact that ecosystem respiration is strongly affected by water availability (Bowling et al., 2002). Another important point to consider is the effect of water stress on the electron partitioning between the cytochrome and the cyanide-resistant, alternative pathway and its consequences for ATP synthesis. Unfortunately, the few studies that have focused on alternative respiration as affected by water stress (Zagdańska, 1995;Collier and Cummins, 1996; González-Meler et al., 1997) used specific inhibitors for the cytochrome (KCN) and alternative (salicylhydroxamic acid [SHAM]) respiratory pathways; this methodology is now known to be invalid (Millar et al., 1995;Day et al., 1996;Lambers et al., 2005). Currently, the only available system to measure electron partitioning between the two respiratory pathways and their actual activities is the use of the oxygen-isotope-fractionation technique McDonald et al., 2003;Ribas-Carbo et al., 2005). This technique is based on the fact that the two terminal oxidases fractionate 18 O differently, with the cytochrome oxidase discriminating less than the alternative oxid...

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Section: The Effect Of Water Stress On Leaf Respirationcontrasting

confidence: 53%

Effects of Water Stress on Respiration in Soybean Leaves

et al. 2005

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“…There is evidence that following a period of desiccation, rates of photosynthesis under high light (2,11,21,25) present before desiccation. For example, increased root resistance could result in low leaf water potentials, and incomplete stomatal opening might then be attributable to low water potentials rather than to an after-effect of desiccation acting on the stomatal mechanism itself.…”

Section: Introductionmentioning

confidence: 99%

“…There is evidence that following a period of desiccation, rates of photosynthesis under high light (2,11,21,25) and transpiration (11,17,21) may remain lower, resistance to water movement through the root system may be larger (17,18), and stomata may open less in light than do those of nondesiccated control plants (12 Leaf water potential was measured by the isopiestic technique with thermocouple pyschrometers which could accommodate either intact leaves (6) or excised leaf tissue (4,10). Several hours before measurements were made, the experimental tissue was rinsed in distilled water and permitted to dry in order to remove surface contaminants.…”

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Recovery of Photosynthesis in Sunflower after a Period of Low Leaf Water Potential

Boyer

1971

Plant Physiol.

115

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Photosynthesis was studied in sunflower plants subjected to 1 to 2 days of desiccation and then permitted to recover. The leaf water potential to which leaves returned after rewatering was dependent on the severity of desiccation and the evaporative conditions. Under moderately evaporative conditions, leaf water potential returned to predesiccation levels after 3 to 5 hours when desiccation was slight. Leaf water potentials remained below predesiccation levels for several days after rewatering when leaf water potentials decreased to -13 to -19 bars during desiccation. Leaf water potential showed no sign of recovery when leaf water potentials decreased to -20 bars or below during desiccation. The lack of full recovery of leaf water potential was attributable to increased resistance to water transport in the roots and stem. The resistance ultimately became large enough to result in death of the leaves because net water loss continued even after the soil had been rewatered.Measurements of photosynthesis were made at high light intensities, where stomatal aperture often affects photosynthesis, and at low light intensities, where the photochemical activity of the leaves limits photosynthesis. Providing leaf water potentials remained above -12 bars during the desiccation period and returned to predesiccation levels during recovery, photosynthesis under both low and high light paralleled the recovery in leaf water potential after rewatering. After desiccation to leaf water potentials below -12 bars, recovery was incomplete under high light and could be attributed to lack of full stomatal opening. Lack of full opening persisted for 3 days and showed no sign of eventual recovery even though leaf water potentials recovered fully. Under low light, however, recovery in photochemical activity was complete within 15 hours after desiccation to leaf water potentials as low as -17 bars.Plants often recover only partially from desiccation after they have been rewatered. There is evidence that following a period of desiccation, rates of photosynthesis under high light (2,11,21,25) present before desiccation. For example, increased root resistance could result in low leaf water potentials, and incomplete stomatal opening might then be attributable to low water potentials rather than to an after-effect of desiccation acting on the stomatal mechanism itself. There are few measurements (7) of the degree to which leaf water potential recovers after a period of desiccation. The present work describes experiments which test whether the incomplete recovery of photosynthesis is associated with leaf water potentials that remain low after rewatering or whether some aspect of the photosynthetic process is inhibited irreversibly by desiccation. MATERIALS AND METHODSSunflower (Helianthus annuus L. var. Russian Mammoth) plants were grown from seed in a controlled environment chamber (day temperature, 29 ± 0.5 C; night temperature, 23 + 0.5 C; relative humidity, 70 + 5%; light intensity, 0.19 cal cm-2 min-1 (fluorescent); photoperiod, 14...

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“…Several metabolic processes, which are completely dependent upon phosphorylated intermediates, are noticeably affected by moisture stress conditions. Photosynthetic rate decreases markedly in severely stressed plants (13). Rate of fixation of CO2 in the dark decreases (12).…”

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confidence: 99%