Leaf H+-ATPase activity and photosynthetic capacity of Cakile maritima under increasing salinity (original) (raw)
Related papers
2015
Reed canarygrass (Phalaris arundinacea) is a good candidate for bioenergy production in Northern and Middle Europe. The crop is well-adapted to cold and drought stress but its resistance to high salinity has not been revealed in details. In this study the effects of 75 and 150 mM NaCl treatments were investigated on the ion accumulation, water potential changes and photosynthetic activity of three Romanian reed canarygrass genotypes, Tardin, Romanesti diverse and Timpuriu. Since cv. Tardin was able to maintain high K+ level and relatively low Na+ concentration in leaf tissues, high stomatal conductance and net CO2 fixation rate under salt stress and as it could maintain the water potential of tissues at control level, this genotype can be defined as salt tolerant. Salt stress induced significant Na+ accumulation, very low K /Na+ ratio, and severe reduction in stomatal conductance and photosynthetic activity in the leaf tissues of Timpuriu cultivar, which proved to be sensitive to hi...
Acta Physiologiae Plantarum, 2011
The aim of this study was to investigate the effects of NaCl-salinity on the physiological attributes in common reed, Phragmites australis (Cav.) Trin. ex Steudel. Plants grew optimally under salinity treatment with standard nutrient solution without added salt and at NaCl concentrations up to 100 mM. Applied for 21 days, NaCl-salinity (300 and 500 mM) caused a significant reduction in growth allocation of all different tissues of P. australis. Shoot growth of reed plants displayed a highly significant correlation with plant–water relations and photosynthetic parameters. The net photosynthetic rate and stomatal conductance of reed plants treated with NaCl-salinity at varying osmotic potential (ψπ) of nutrient solutions were positively correlated, and the former variable also had a strong positive relationship with transpiration rate. Leaf water potential and ψπ followed similar trends and declined significantly as ψπ of watering solutions was lowered. The increase in total inorganic nutrients resulting from increased Na+ and Cl− in all tissues and K+, Ca2+ and Mg2+ concentrations were maintained even at the most extreme salt concentration. Common reed exhibited high K+/Na+ and Ca2+/Na+ selectivity ratios over a wide range of salinities under NaCl-salinity. These findings suggest that reed plants were able to adapt well to high salinities by lowering their leaf ψπ and the adjustment of osmotically active solutes in the leaves.
Responses of Batis maritima plants challenged with up to two-fold seawater NaCl salinity
Journal of Plant Nutrition and Soil Science, 2010
Batis maritima is a promising halophyte for sand-dune stabilization and saline-soil reclamation. This species has also applications in herbal medicine and as an oilseed crop. Here, we address the plant response to salinity reaching up to two-fold seawater concentration (0–1000 mM NaCl), with a particular emphasis on growth, water status, mineral nutrition, proline content, and photosystem II integrity. Plant biomass production was maximal at 200 mM NaCl, and the plants survived even when challenged with 1000 mM NaCl. Plant water status was not impaired by the high accumulation of sodium in shoots, suggesting that Na+ compartmentalization efficiently took place in vacuoles. Concentrations of Mg2+ and K+ in shoots were markedly lower in salt-treated plants, while that of Ca2+ was less affected. Soluble-sugar and chlorophyll concentrations were hardly affected by salinity, whereas proline concentration increased significantly in shoots of salt-treated plants. Maximum quantum efficiency (Fv/Fm), quantum yield of PSII (ΦPSII), and electron-transport rate (ETR) were maximal at 200–300 mM NaCl. Both nonphotochemical quenching (NPQ) and photochemical quenching (qP) were salt-independent. Interestingly, transferring the plants previously challenged with supraoptimal salinities (400–1000 mM NaCl) to the optimal salinity (200 mM NaCl) substantially restored their growth activity. Altogether, our results indicate that B. maritima is an obligate halophyte, requiring high salt concentrations for optimal growth, and surviving long-term extreme salinity. Such a performance could be ascribed to the plant capability to use sodium for osmotic adjustment, selective absorption of K+ over Na+ in concomitance with the stability of PSII functioning, and the absence of photosynthetic pigment degradation.
Flora, 2010
Aim of the present study was to investigate the effects of two key environmental factors of estuarine ecosystems, salinity and hypoxia, on the physiological attributes in reed plants (Phragmites australis (Cav.) Trin. ex Steudel). Growth, leaf gas exchange, water (and ion) relations, and osmotic adjustment were determined in hydroponically grown plants exposed to hypoxia at varying NaCl-salinity concentrations (0, 50, 100, and 200 mM). Plants grew well under hypoxia treatment with standard nutrient solution without added salt and at NaCl concentrations up to 100 mM. Reed plants were able to produce and allocate phytomass to all their organs even at the highest salt level (200 mM NaCl). In plants subjected to hypoxia at various water potentials no clear relationships were found between growth and photosynthetic parameters except for g s , whereas growth displayed a highly significant correlation with plant-water relations. A and g s of reed plants treated with hypoxia at varying water potential of nutrient solutions were positively correlated and the former variable also had a strong positive relationship with E. Leaf C w and C p followed a similar trend and declined significantly as water potential of watering solutions was lowered. Highly significant positive correlations were identified between leaf C w and photosynthetic parameters. At all NaCl concentrations, the increase in total inorganic ions resulted from increased Na + and Cl À while K + , Ca 2 + , and Mg 2 + concentrations decreased with increasing osmolality of nutrient solutions. Common reed has an efficient mechanism of Na + exclusion from the leaves and exhibited a high leaf K + /Na + selectivity ratio over a wide range of salinities under hypoxia treatment. In Phragmites australis grown in 200 mM NaCl, K + contributed 17% toC p , whereas Na + and Cl À accounted for only 11% and 6%, respectively. At the same NaCl concentration, the estimated contribution of proline to C p was less than 0.2%. Changes in leaf turgor occurred with a combined effect of salinity and hypoxia, suggesting that reed plants could adjust their water status sufficiently.
Trees, 2010
During a 30-day period of increasing salinity, we examined the effects of NaCl on leaf H ?-ATPase and salinity tolerance in 1-year-old plants of Populus euphratica Oliv. (salt resistant) and P. popularis 35-44 (P. popularis) (salt sensitive). Electron probe X-ray microanalysis of leaf mesophyll revealed that P. euphratica had a higher ability to retain lower NaCl concentrations in the cytoplasm, as compared to P. popularis. The sustained activity of H ? pumps (by cytochemical staining) in salinised P. euphratica suggests a role in energising salt transport through the plasma membrane (PM) and tonoplast. Saltinduced alterations of leaf respiration, ATP content and expression of PM H ?-ATPase were compared between the two species. Results show that P. euphratica retained a constant respiratory rate, ATP production and protein abundance of PM H ?-ATPase (by Western blotting) in salt-stressed plants. P. euphratica was able to maintain a comparatively high capacity of ATP hydrolysis and H ? pumping during prolonged salt exposure. By contrast, the activity and expression of PM H ?-ATPase were markedly decreased in P. popularis leaves in response to salt stress. Furthermore, NaCl-stressed P. popularis plants showed a marked decline of respiration (70%) and ATP production (66%) on day 30. We conclude that the inability of P. popularis to transport salt to the apoplast and vacuole was partly due to the decreased activity of H ? pumps. As a consequence, cytosolic ion concentrations were observed to be comparatively high for an extended period of time, so that cell metabolism, in particular respiration, was disrupted in P. popularis leaves.
Acta Physiologiae Plantarum, 2011
Basil (Ocimum basilicum L., cultivar Genovese) plants were grown in Hoagland solution with or without 50 mM NaCl or 25 mM Na 2 SO 4. After 15 days of treatment, Na 2 SO 4 slowed growth of plants as indicated by root, stem and leaf dry weight, root length, shoot height and leaf area, and the effects were major of those induced by NaCl. Photosynthetic response was decreased more by chloride salinity than by sulphate. No effects in both treatments on leaf chlorophyll content, maximal efficiency of PSII photochemistry (F v /F m) and electron transport rate (ETR) were recorded. Therefore, an excess of energy following the limitation to CO 2 photoassimilation and a down regulation of PSII photochemistry was monitored under NaCl, which displays mechanisms that play a role in avoiding PSII photodamage able to dissipate this excess energy. Ionic composition (Na ? , K ? , Ca 2? , and Mg 2?) was affected to the same extent under both types of salinity, thus together with an increase in leaves Cl-, and roots SO 4 2in NaCl and Na 2 SO 4-treated plants, respectively, may have resulted in the observed growth retardation (for Na 2 SO 4 treatment) and photosynthesis activity inhibition (for NaCl treatment), suggesting that those effects seem to have been due to the anionic component of the salts.
Tree Physiology, 2011
Plant growth response to salinity on a scale of years has not been studied in terms of growth analysis. To gain insights into this topic, 2-year-old Mediterranean Fan Palm (Chamaerops humilis L.) and Mexican Fan Palm (Washingtonia robusta H. Wendl) seedlings, each with its own distinct plant morphology, were grown for 2 years in a peat soil and irrigated with water of 2 dS m −1 (control) or 8 dS m −1 (saline). Plants were harvested on seven occasions and the time trends in relative growth rate (RGR, the rate of increase of biomass per unit of biomass already existing) and its components were analysed. In the long term, salinity produced a slight reduction in the mean RGR, values in both species. In the short term, salinity caused a reduction in RGR. However, during the second year, plants irrigated with 8 dS m −1 grew somewhat more quickly than the control plants, probably as a result of delay in the growth kinetics due to salinity. Regarding RGR components, leaf nitrogen productivity (the rate of biomass gain per unit leaf N and time) was the major factor causing the differences in RGR resulting from salinity. Washingtonia robusta showed a relatively high plasticity in plant morphology by increasing root and decreasing stem biomass allocation in the presence of salinity. However, the long-term response of W. robusta to salinity, based to a great extent, on this morphological plasticity, was less effective than that of C. humilis, which is based mainly on the contribution of leaf N to RGR values.
Plant Physiology and Biochemistry, 2015
Casuarina glauca is an actinorhizal tree which establishes root-nodule symbiosis with N 2-fixing Frankia bacteria. This plant is commonly found in saline zones and is widely used to remediate marginal soils and prevent desertification. The nature of its ability to survive in extreme environments and the extent of Frankia contribution to stress tolerance remain unknown. Thus, we evaluated the ability of C. glauca to cope with salt stress and the influence of the symbiosis on this trait. To this end, we analysed the impact of salt on plant growth, mineral contents, water relations, photosynthetic-related parameters and nonstructural sugars in nodulated vs. non-nodulated plants. Although the effects on photosynthesis and stomatal conductance started to become measurable in the presence of 200 mM NaCl, photochemical (e.g., photosynthetic electron flow) and biochemical (e.g., activity of photosynthetic enzymes) parameters were only strongly impaired when NaCl levels reached 600 mM. These results indicate the maintenance of high tissue hydration under salt stress, probably associated with enhanced osmotic potential. Furthermore, the maintenance of photosynthetic assimilation potential (A max), together with the increase in the quantum yield of down-regulated energy dissipation of PSII (Y NPQ), suggested a downregulation of photosynthesis instead of photo-damaging effects. A comparison of the impact of increasing NaCl levels on the activities of photosynthetic (RubisCO and ribulose-5 phosphate kinase) and respiratory (pyruvate kinase and NADH-dependent malate dehydrogenase) enzymes vs. photosynthetic electron flow and fluorescence parameters, revealed that biochemical impairments are more limiting than photochemical damage. Altogether, these results indicate that, under controlled conditions, C. glauca tolerates high NaCl levels and that this capacity is linked to photosynthetic adjustments.
Journal of Experimental Botany, 1996
The halophyte Salicornia bigelovii Torr. shows optimal growth and Na + accumulation in 200 mM NaCI and reduced growth under lower salinity conditions. The ability to accumulate and compartmentalize Na + may result, in part, from stimulation of the H + -ATPases on the plasma membrane (PM-ATPase) and vacuolar membranes (V-ATPase). To determine if these two primary transport systems are involved in salt tolerance, shoot fresh weight (FW) and activity of the PM-and V-ATPases from shoots in Salicornia grown in 5 and 200 mM NaCI were compared. Higher PM-ATPase activity (60%) and FW (60%) were observed in plants grown in 200 mM NaCI and these stimulations in growth and enzyme activity were specific for Na + and not observed with Na + added in vitro. V-ATPase activity was significantly stimulated in vivo and in vitro (26% and 46%, respectively) after exposure to 200 mM NaCI, and stimulation was Na + -specific. Immunoblots indicated that the increases in activity of the H + -ATPases from plants grown in 200 mM NaCI was not due to increases in protein expression. These studies suggest that the H + -ATPases in Salicornia are important in salt tolerance and provide a biochemical framework for understanding mechanisms of salt tolerance in plants.
Plant and soil, 2003
The effect of salinity on nitrate influx, efflux, nitrate net uptake rate and net nitrogen translocation to the shoot was assessed in a 15 N steady state labelling experiment in the halophyte Plantago maritima L. raised for 14 days on solution supplied with 50, 100 and 200 mol m −3 sodium chloride or without sodium chloride. Additionally, salinity induced changes in root morphology were determined. Specific root length increased upon exposure to elevated sodium chloride concentrations due to variations in biomass allocation and length growth of the tap root. Changes in root morphology, however, had a minor effect on nitrate fluxes when expressed on a root fresh weight basis. The decreased rate of nitrate net uptake in plants grown on elevated levels of sodium chloride was almost entirely due to a decrease in nitrate influx. Expressed as a proportion of influx, nitrate efflux remained unchanged and was even lower at the highest salinity level. At all sodium chloride concentrations applied the initial rate of nitrogen net translocation to the shoot decreased relative to the rate of nitrate net uptake. It is concluded that under steady state conditions the negative effect of sodium chloride on the rate of nitrate net uptake at non growth-limiting salinity levels was due to the interaction between sodium chloride and nitrate transporters in the root plasma membrane and/or processes mediating the translocation of nitrogen compounds, possibly nitrate, to the shoot.