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1.
Although some plant responses to salinity have been characterized, the precise mechanisms by which salt stress damages plants are still poorly understood especially in woody plants. In the present study, the physiological and biochemical responses of Broussonetia papyrifera, a tree species of the family, Moraceae, to salinity were studied. In vitro-produced plantlets of B. papyrifera were treated with varying levels of NaCl (0, 50, 100 and 150 mM) in hydroponic culture. Changes in ion contents, accumulation of H2O2, as well as the activities and isoform profiles of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the leaves, stems and roots were investigated. Under salt stress, there was higher Na+ accumulation in roots than in stems and leaves, and Ca2 +, Mg2 + and P3 + content, as well as K+/Na+ ratio were affected. NaCl treatment induced an increase in H2O2 contents in the tissues of B. papyrifera. The work demonstrated that activities of antioxidant defense enzymes changed in parallel with the increased H2O2 and salinity appeared to be associated with differential regulation of distinct SOD and POD isoenzymes. Moreover, SDS-PAGE analysis of total proteins extracted from leaves and roots of control and NaCl-treated plantlets revealed that in the leaves salt stress was associated with decrease or disappearance of some protein bands, and induction of a new protein band after exposure to 100 and 150 mM NaCl. In contrast, NaCl stress had little effect on the protein pattern in the roots. In summary, these findings may provide insight into the mechanisms of the response of woody plants to salt stress. 相似文献
2.
W. Liu Y. Zhang X. Yuan Y. Xuan Y. Gao Y. Yan 《Russian Journal of Plant Physiology》2016,63(1):132-142
In the present study, the physiological responses of Nitraria tangutorum Bobr. seedlings to NaCl stress and the regulatory function of exogenous application of salicylic acid (SA) were investigated. NaCl in low concentration (100 mM) increased while in higher concentrations (200–400 mM) decreased the individual plant dry weights (wt) of seedlings. Decreased relative water content (RWC) and chlorophyll content were observed in the leaves of seedlings subjected to salinity stress (100–400 mM NaCl). Furthermore, NaCl stress significantly increased electrolyte leakage and malondialdehyde (MDA) content. The levels of osmotic adjustment solutes including proline, soluble sugars, and soluble protein were enhanced under NaCl treatments as compared to the control. In contrast, exogenous application of SA (0.5–1.5 mM) to the roots of seedlings showed notable amelioration effects on the inhibition of individual plant dry wt, RWC, and chlorophyll content. The increases in electrolyte leakage and MDA content in the leaves of NaCl-treated seedlings were markedly inhibited by SA application. The SA application further increased the contents of proline, soluble sugars, and soluble protein. The activities of antioxidant enzymes including superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were up-regulated by NaCl stress and the activities of SOD, POD, and CAT were further enhanced by SA treatments. Application of SA in low concentration (0.5 mM) enhanced while in higher concentrations (1.0 and 1.5 mM) inhibited APX activities in leaves of NaCl-treated seedlings. These results indicate that SA effectively alleviated the adverse effects of NaCl stress on N. tangutorum. 相似文献
3.
Twenty days’ exposure to 50 or 100 mM NaCl in the rooting medium substantially increased fresh and dry weights of seedling
shoots of the recretohalophyte Limonium sinense while 200 or 300 mM were increasingly inhibitory. KCl treatment was only slightly stimulating (50 mM) or strongly inhibitory
(100–300 mM). Lesser effects on leaf area were also seen. Diameter of foliar salt glands was significantly larger than that
of controls in 100 and 200 mM NaCl with the effect being reversed at higher concentrations. Gland enlargement was also observed
in the presence of 100 mM KCl, while larger concentrations reduced gland size. Generally, gland diameter was larger in the
presence of NaCl than in KCl. NaCl and KCl also increased gland number per leaf and secretion rate per gland. At 100 and 200 mM
NaCl or KCl, Na+ secretion per leaf from NaCl-treated plants exceeded K+ secretion rate from KCl-treated plants while at 200 mM, Na+ secretion per gland was significantly higher for Na+ than for K+. Evidence of cell death in leaves of salt-treated plants using Evans blue staining indicates that release of cell contents
through loss of membrane integrity contributed to the secretion values. We conclude that the greater tolerance of L. sinenseto to NaCl compared to KCl is linked to the more effective secretion of Na+ than of K+ and, in turn, to a greater stimulation of salt gland formation and activity and larger gland diameter. 相似文献
4.
Structural changes induced by NaCl in companion and transfer cells of Medicago sativa blades 总被引:3,自引:0,他引:3
Boughanmi N Michonneau P Verdus MC Piton F Ferjani E Bizid E Fleurat-Lessard P 《Protoplasma》2003,220(3-4):179-187
Summary. Medicago sativa var. Gabes is a perennial glycophyte that develops new shoots even in high salinity (150 mM NaCl). In the upper exporting
leaves, K+ is high and Na+ is low by comparison with the lower leaves, where Na+ accumulation induces chlorosis after 4 weeks of NaCl treatment. By secondary ion mass spectroscopy, a low Na+/K+ ratio was detected in the phloem complex of blade veins in these lower leaves. By transmission electron microscopy, the ultrastructural
features were observed in the phloem complex. In the upper leaves of both control and NaCl-treated plants, companion cells
in minor veins were found to be transfer cells. These cells may well be involved in the intravenous recycling of ions and
in Na+ flowing out of exporting leaves. Under the effect of NaCl, companion cells in the main veins develop transfer cell features,
which may favor the rate of assimilate transport from exporting leaves toward meristems, allowing the positive balance necessary
for the survival in salt conditions. These features no longer assist the lower leaves when transfer cells are necrotized in
both minor and main veins of NaCl-treated plants. As transfer cells are the only degenerating phloem constituent, our observations
emphasize their role in controlling nutrient (in particular, Na+) fluxes associated with the stress response.
Received February 20, 2002; accepted August 30, 2002; published online March 11, 2003 相似文献
5.
The antioxidative defense mechanism to salinity was assessed by monitoring the activities of some antioxidative enzymes and
levels of antioxidants in an obligate halophyte, Salicornia brachiata, subjected to varying levels of NaCl (0, 200, 400, and 600 mM) under hydroponic culture. In the shoots of S. brachiata, salt treatment preferentially enhanced the activities of ascorbate peroxidase (APX), guaiacol peroxidase (POX), glutathione
reductase (GR), and superoxide dismutase (SOD), whereas it induced the decrease of catalase (CAT) activity. Similarly, salinity
caused an increase in total glutathione content (GSH + GSSG) and a decrease in total ascorbate content. Growth of S. brachiata was optimum at 200 mM NaCl and decreased with further increase in salinity. Salinity caused an increase in Na+ content and a decrease in K+ content of shoots. Proline levels did not change at low (0-200 mM NaCl) or moderate (400 mM NaCl) salinities, whereas a significant
increase in proline level was observed at high salinity (600 mM NaCl). Accumulation of Na+ may have a certain role in osmotic homeostasis under low and moderate salinities in S. brachiata. Parameters of oxidative stress such as malondialdehyde (MDA), a product of lipid peroxidation, and H2O2 concentrations decreased at low salinity (200 mM NaCl) and increased at moderate (400 mM NaCl) and high salinities (600 mM
NaCl). As a whole, our results suggest that the capacity to limit ionic and oxidative damage by the elevated levels of certain
antioxidative enzymes and antioxidant molecules is important for salt tolerance of S. brachiata. 相似文献
6.
Taieb Tounekti Sergi Munné-Bosch A.M. Vadel Chaker Chtara Habib Khemira 《Plant Physiology and Biochemistry》2010,48(10-11):813-821
The potential of four essential cations (K+, Ca2+, Mg2+ and Fe2+) to alleviate salt toxicity was studied in sage (Salvia officinalis L.) plants grown in pots. Two concentrations of the following chloride salts: KCl, CaCl2, MgCl2 and FeCl3, were used together with 100 mM NaCl to study the effects of these nutrients on plant growth, leaf essential oils (EOs) and phenolic diterpenes composition. The sage plants accumulated Na+ in their leaves (includers); this has affected secondary metabolites’ biosynthesis. Treatment with 100 mM NaCl slightly decreased borneol and viridiflorol, while increased manool concentrations. Addition of KCl, CaCl2 and MgCl2 increased considerably in a dose-dependent manner the oxygen-containing monoterpenes (1.8-cineole, camphor, β-thujone and borneol) in 100 mM NaCl-treated sage. Whereas, the contents of viridiflorol decreased further with the addition of KCl in 100 mM NaCl-treated sage. Our results suggest that the changes in EOs composition were more related to K+ and Ca2+ availability than to Na+ toxicity. Furthermore, treatment with NaCl decreased by 50% carnosic acid (CA), a potent antioxidant, content in the leaves. K+ and Ca2+ promoted the accumulation of CA and its methoxylated form (MCA) in the leaves. The concentration of CA was positively correlated with leaf K+ (r = 0.56, P = 0.01) and Ca2+ (r = 0.44, P = 0.05) contents. It appears that different salt applications in combination with NaCl treatments had a profound effect on EOs and phenolic diterpene composition in sage. Therefore, ionic interactions may be carefully considered in the cultivation of this species to get the desired concentrations of these secondary metabolites in leaf extracts. 相似文献
7.
The present study demonstrates the regeneration of plantlets of guava (Psidium guajava L.) from somatic embryos developed under salt-stress conditions. With increasing concentrations of NaCl in induction medium
(MS + 4.52 μM 2,4-d + 5% sucrose) from 0 to 200 mM, the number of somatic embryos per responsive explant decreased. Somatic embryos induced on
0–100 mM NaCl containing medium developed into torpedo stages, whereas, the development of somatic embryos that differentiated
on 150 and 200 mM NaCl-supplemented medium was arrested prior to torpedo stage and did not undergo maturation phase. Somatic
embryos that developed on NaCl-containing medium, showed better germination in the presence of NaCl as compared with those
developed on medium without NaCl. The effect of increasing salt-stress was also investigated on plant growth, chlorophyll
and carotenoids, Na+ and K+, and proline and glycine betaine accumulation in in vitro grown plantlets. The level of Na+ in leaves increased with increasing concentrations of NaCl in the medium. Accumulation of free proline and glycine betaine
in leaves significantly increased with increasing salinity. The results suggest that accumulation of proline and glycine betaine
may be important for osmotic adjustment in guava under salinity stress. 相似文献
8.
9.
Samia Oueslati Najoua Karray-Bouraoui Houneïda Attia Mokded Rabhi Riadh Ksouri Mokhtar Lachaal 《Acta Physiologiae Plantarum》2010,32(2):289-296
Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions
of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses.
Physiological and biochemical parameters were assessed in the plant organs after 2 weeks of salt treatment with 25, 50, 75
and 100 mM NaCl. Results showed that, growth was reduced even by 25 mM, and salt effect was more pronounced in shoots (leaves
and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline
conditions. Leaf and root guaiacol peroxidase activity showed an increase by different concentration of NaCl, but superoxide
dismutase activity in the same organs showed a slight modification in NaCl-treated leaves and roots. Moreover, polyphenol
contents and antioxidant activity were analysed in M. pulegium leaves and roots under salt constraint. The analysis showed an increase of total polyphenol content (2.41–8.17 mg gallic
acid equivalent g−1 dry weight) in leaves. However, methanol extract of leaves at 100 mM NaCl displayed the highest DPPH· scavenging ability
with the lowest IC50 value (0.27 μg ml−1) in comparison with control which exhibited IC50 equal to 0.79 μg ml−1. 相似文献
10.
C. Chatzissavvidis G. Veneti I. Papadakis I. Therios 《Plant Cell, Tissue and Organ Culture》2008,95(1):37-45
The effect of salinity on the non-enzymic and enzymic antioxidant activity, shoot proliferation and nutrient accumulation
was studied in in vitro cultures of the rootstock CAB-6P (Prunus cerasus L.). Three concentrations (0, 30 and 60 mM) of NaCl or CaCl2 were added to a modified MS medium. Between the two salt treatments used, only the explants treated with CaCl2 presented significant decrease in growth parameters. The concentrations of Na+ and Cl− in the explants treated with NaCl were increased, as NaCl in the culture medium increased. Furthermore, in the explants treated
with CaCl2 the concentrations of Ca2+ and Cl− were increased while that of K+ decreased, as CaCl2 concentration increased. The activity of peroxidase in leaves as well as the number of its anionic isoforms was increased
under 30 mM CaCl2 as well as 60 mM NaCl or CaCl2. On the contrary, increasing salinity, from 0 to 60 mM CaCl2, resulted in a reduction of the catalase activity in leaves followed by disappearance of the only one catalase isoform that
was detected in leaves (60 mM CaCl2). In the stems of the explants treated with NaCl the peroxidase activity was reduced. In the stems and leaves of the explants
grown in saline substrate the non-enzymic antioxidant activity was significantly increased. The results suggest that the stems
and leaves of CAB-6P explants presented variable antioxidant responses that were depended on the salt form used. The contribution
of enzymic and non-enzymic protection mechanisms to the adaptation of CAB-6P explants under salinity stress is discussed. 相似文献
11.
I. Tarchoune C. Sgherri R. Izzo M. Lachaal Z. Ouerghi F. Navari-Izzo 《Plant Physiology and Biochemistry》2010,48(9):772-777
Soils and ground water in nature are dominated by chloride and sulphate salts. There have been several studies concerning NaCl salinity, however, little is known about the Na2SO4 one. The effects on antioxidative activities of chloride or sodium sulphate in terms of the same Na+ equivalents (25 mM Na2SO4 and 50 mM NaCl) were studied on 30 day-old plants of Ocimum basilicum L., variety Genovese subjected to 15 and 30 days of treatment. Growth, thiobarbituric acid reactive substances (TBARS), relative ion leakage ratio (RLR), hydrogen peroxide (H2O2), ascorbate and glutathione contents as well as the activities of ascorbate peroxidase (APX, EC 1.11.1.11); glutathione reductase (GR, EC 1.6.4.2) and peroxidases (POD, EC 1.11.1.7) were determined. In leaves, growth was more depressed by 25 mM Na2SO4 than 50 mM NaCl. The higher sensitivity of basil to Na2SO4 was associated with an enhanced accumulation of H2O2, an inhibition of APX, GR and POD activities (with the exception of POD under the 30-day-treatment) and a lower regeneration of reduced ascorbate (AsA) and reduced glutathione (GSH). However, the changes in the antioxidant metabolism were enough to limit oxidative damage, explaining the fact that RLR and TBARS levels were unchanged under both Na2SO4 and NaCl treatment. Moreover, for both salts the 30-day-treatment reduced H2O2 accumulation, unchanged RLR and TBARS levels, and enhanced the levels of antioxidants and antioxidative enzymes, thus achieving an adaptation mechanism against reactive oxygen species. 相似文献
12.
Kamel A. H. Tartoura Sahar A. Youssef El-Sayed A. A. Tartoura 《Plant Growth Regulation》2014,74(3):299-310
The aim of this study was to investigate the effectiveness of compost in alleviating the negative impacts of salinity on tomato (Solanum lycopersicum cv. Hybrid Guardian F1) plants. An experiment was performed to evaluate the response of plants to compost addition to soil at a rate of 55 g kg?1 soil and NaCl salinity at 0, 50, 100 mM. The results obtained showed a significant decrease in growth-related parameters, i.e. shoot- and root-fresh weight (FW), fruit FW, and fruit yield. Meanwhile, salinity resulted in a significant increase of Na+, electrolyte leakage, lipid peroxidation and hydrogen peroxide in the leaves, but a decrease of N, P, S, K+, Ca2+ and Mg2+ level, as well as K+/Na+ ratio in a dose dependent manner. Under these conditions compost nullified the above negative impacts of salinity caused by 50 mM NaCl and to some extent at 100 mM NaCl. The salinity mediated enhancement in biomarkers of oxidative stress was considerably decreased by compost application which increased the level of ascorbate (ASC) and glutathione (GSH) and the ratios of ASC/dehydroascorbate (DHA) and GSH/glutathione disulfide, as well as the activities of ASC peroxidase, monodehydroascorbate reductase, DHA reductase and GSH reductase in NaCl-treated plants, implying a better reactive oxygen species scavenging system. Data also indicated that compost application resulted in higher activities of leaf carbonic anhydrase, ribulose bisphosphate carboxylase, nitrate reductase and adenosine triphosphate-sulfurylase. These findings collectively suggest that compost plays a pivotal role in inducing salinity tolerance via enhancing an efficient antioxidant system and key C, N and S assimilatory enzymes. 相似文献
13.
Shah Safdar Hussain Tobita Satoshi Shono Mariko 《Plant Cell, Tissue and Organ Culture》2002,71(2):95-101
Cell lines of Oryza sativa L. (cv. Taipei-309) were adapted to 30 mM LiCl and 150 mM NaCl. Both adapted lines were considerably more tolerant than non adapted line when grown on 200, 250 and 300 mM NaCl and 30 mM LiCl stresses. The tolerance of LiCl-adapted line to NaCl (150 to 300 mM) and the tolerance of NaCl-adapted cells line to LiCl (30 mM) indicated that there was a cross-adaptation towards alkali metals (Na+ and Li+) not the Cl–. Na+ and K+ contents of all lines which increased with increasing medium salinity but to a different degree. The increase in Na+ and K+ content in NaCl-adapted and non-adapted lines were comparable, while LiCl-adapted line accumulated significantly lower Na+and higher K+ content. Proline content of all lines increased with the increase in NaCl-stress but the magnitude of increase was much higher in the LiCl-adapted than other lines. The differential response of adapted lines to NaCl stress in accumulating proline and maintaining the ionic contents reveals that adapted lines have evolved different features of adaptation to cope with NaCl stress. 相似文献
14.
Karim Ben Hamed Antonella Castagna Elkahoui Salem Annamaria Ranieri Chedly Abdelly 《Plant Growth Regulation》2007,53(3):185-194
The present study was carried out to compare the effect of NaCl on growth, cell membrane damage, and antioxidant defences
in the halophyte Crithmum maritimum L. (sea fennel). Physiological and biochemical changes were investigated under control (0 mM NaCl) and saline conditions
(100 and 300 mM NaCl). Biomass and growth of roots were more sensitive to NaCl than leaves. Roots were distinguished from
leaves by increased electrolyte leakage and high malondialdehyde (MDA) concentration. Superoxide dismutase (SOD), catalase
(CAT) and ascorbate peroxidase (APX) activities, ascorbic acid (AA) and glutathione (GSH) concentrations were lower in the
roots than in the leaves of control plants. The different activity patterns of antioxidant enzymes in response to 100 and
300 mM NaCl indicated that leaves and roots reacted differently to salt stress. Leaf CAT, APX and glutathione reductase (GR)
activities were lowest at 300 mM NaCl, but they were unaffected by 100 mM NaCl. Only SOD activity was reduced in the latter
treatment. Root SOD activity was significantly decreased in response to 300 mM NaCl and root APX activity was significantly
higher in plants treated with 100 and 300 mM compared to the controls. The other activities in roots were insensitive to salt.
The concentration of AA decreased in leaves at 100 and 300 mM NaCl, and in roots at 300 mM NaCl, when compared to control
plants. The concentrations of GSH in NaCl-treated leaves and roots were not significantly different from the controls. In
both organs, AA and GSH were predominating in the total pool in ascorbic acid and glutathione, under control or saline conditions. 相似文献
15.
Evren Yildiztugay Ceyda Ozfidan-Konakci Mustafa Kucukoduk 《Acta Physiologiae Plantarum》2014,36(1):125-138
Thermopsis turcica is distributed naturally in saline soils. Interestingly, how T. turcica can live in harsh salt conditions is unknown. To study its defense responses under salinity, T. turcica was grown in a medium containing 100 and 200 mM NaCl for 7 and 14 days. Physiological parameters, ion contents, reactive oxygen species accumulation, activities of antioxidant enzymes/isozymes, NADPH oxidase enzyme/isozyme, lipid peroxidation (TBARS) and osmolyte contents were investigated. Stress caused a rapid decline in relative growth rate, relative water content and chlorophyll fluorescence (F v/F m) under both NaCl treatments. These traits were more suppressed at 200 mM NaCl. The decline in osmotic potential (Ψ Π) with salinity increased the gradient for water flux into the cell and assisted in turgor maintenance. The increased membrane permeability under stress caused the entrance of excess Na+ and K+ into the cell. Stress decreased superoxide dismutase, catalase and peroxidase after 14 days of growth in 200 mM NaCl, whereas glutathione reductase (GR) increased throughout the experiment. While ascorbate peroxidase (APX) increased by 44 % at 7 days, it decreased after 14 days exposure to 200 mM NaCl. 200 mM NaCl caused the highest increase in TBARS at 14 days, indicating a decrease in OH· scavenging activity. Increasing concentrations of salinity caused an increase in glycine betaine (GB) and choline (Cho), though an increase in proline was only observed at 200 mM NaCl for 14 days. Briefly, H2O2 was more efficiently eliminated in 100 mM-treated plants by the ascorbate–glutathione cycle in which APX acts a strong catalyst together with GR. Also, Cho and GB help to maintain osmotic adjustment and cytoplasmic function. 相似文献
16.
Salt-induced expression of genes related to Na+/K+ and ROS homeostasis in leaves of salt-resistant and salt-sensitive poplar species 总被引:3,自引:0,他引:3
Mingquan Ding Peichen Hou Xin Shen Meijuan Wang Shurong Deng Jian Sun Fei Xiao Ruigang Wang Xiaoyang Zhou Cunfu Lu Deqiang Zhang Xiaojiang Zheng Zanmin Hu Shaoliang Chen 《Plant molecular biology》2010,73(3):251-269
17.
Mohd Idrees M. Naeem Tariq Aftab M. Masroor A. Khan Moinuddin 《Acta Physiologiae Plantarum》2011,33(3):987-999
A pot experiment was conducted to find out whether the foliar spray of salicylic acid (SA) could successfully ameliorate the
adverse effects of salinity stress on periwinkle. Thirty-day-old plants were supplied with Control; 0 mM NaCl + 10−5 M SA (T1); 50 mM NaCl + 0 SA (T2); 100 mM NaCl + 0 SA (T3); 150 mM NaCl + 0 SA (T4); 50 mM NaCl + 10−5 M SA (T5); 100 mM NaCl + 10−5 M SA (T6); 150 mM NaCl + 10−5 M SA (T7). The plants were sampled 90 days after sowing to assess the effect of SA on stressed and unstressed plants. Salt stress
significantly reduced the growth attributes including plant height, leaf-area index, shoot and root fresh weights, shoot and
root dry weights. Increasing NaCl concentrations led to a gradual decrease in photosynthetic parameters and activities of
nitrate reductase and carbonic anhydrase. Ascorbic acid, total alkaloids and antioxidants enzymes superoxide dismutase, catalase
and peroxidase also declined in NaCl-treated plants. The plants, undergoing NaCl stress, exhibited a significant increase
in electrolyte leakage and proline content. Foliar application of SA (10−5 M) reduced the damaging effect of salinity on plant growth and accelerated the restoration of growth processes. It not only
improved the growth parameters but also reversed the effects of salinity. Total alkaloid content was improved by SA application
both in unstressed and stressed plants. The highest level of total alkaloid content recorded in leaves of SA-treated stressed
plants was 11.1%. Foliar spray of SA overcame the adverse effect of salinity by improving the content of vincristine (14.0%)
and vinblastine (14.6%) in plants treated with 100 M NaCl. 相似文献
18.
HuiPing Mao Fumiko Iwanaga Norikazu Yamanaka Fukuju Yamamoto 《Landscape and Ecological Engineering》2008,4(2):75-82
Growth, photosynthesis, and Na+, K+, and Ca2+ distributions were investigated in 2-year-old hydroponically cultured Populus alba L. cuttings exposed to salt stresses (0, 0.85, 8.5, 17, and 85 mM NaCl in experiment 1 and 0, 50, 100, 150, and 200 mM in
experiment 2) for 4 weeks in 2/5 Hoagland solution. Salt did not markedly inhibit height growth and diameter increment in
150 and 100 mM NaCl, respectively. The 85 mM NaCl treatment increased the dry weights of roots and total dry weight of plants,
while 150 mM NaCl significantly reduced the dry weights of leaves, stems, and total plant weight. The decline in the photosynthetic
rate lagged 2 weeks behind that of stomatal conductance in the 50 and 100 mM salt solutions. Different ions exhibited different
distributions in different parts of the plant. Most Na+ ions were excluded and/or compartmentalized in roots at low and moderate salt stress (≤50 mM). K+ content in leaves increased with the increase in the salt concentration in the growth solutions. 相似文献
19.
Effects of NaCl salinity on growth, morphology, photosynthesis and proline accumulation of Salvinia natans 总被引:2,自引:0,他引:2
The effects of NaCl salinity on growth, morphology and photosynthesis of Salvinia natans (L.) All. were investigated by growing plants in a growth chamber at NaCl concentrations of 0, 50, 100 and 150 mM. The relative growth rates were high (ca. 0.3 d−1) at salinities up to 50 mM and decreased to less than 0.2 d−1 at higher salinities, but plants produced smaller and thicker leaves and had shorter stems and roots, probably imposed by the osmotic stress and lowered turgor pressure restricting cell expansion. Na+ concentrations in the plant tissue only increased three-fold, but uptake of K+ was reduced, resulting in very high Na+/K+ ratios at high salinities, indicating that S. natans lacks mechanisms to maintain ionic homeostasis in the cells. The contents of proline in the plant tissue increased at high salinity, but concentrations were very low (<0.1 μmol g−1 FW), indicating a limited capacity of S. natans to synthesize proline as a compatible compound. The potential photochemical efficiency of PSII (Fv/Fm) of S. natans remained unchanged at 50 mM NaCl but was reduced at higher salinities, and the photosynthetic capacity (ETRmax) was significantly reduced at 50 mM NaCl and higher. It is concluded that S. natans is a salt-sensitive species lacking physiological measures to cope with exposure to high NaCl salinity. At low salinities salts are taken up and accumulate in old leaves, and high growth rates are maintained because new leaves are produced at a higher rate than for plants not exposed to salt. 相似文献
20.
Sabah Yousfi Mokded Rabhi Kamel Hessini Chedly Abdelly Mohamed Gharsalli 《Plant biology (Stuttgart, Germany)》2010,12(4):650-658
Physiological and biochemical responses of Hordeum maritimum and H. vulgare to salt stress were studied over a 60‐h period. Growth at increasing salinity levels (0, 100, 200 and 300 mM NaCl) was assessed in hydroponic culture. H. maritimum was shown to be a true halophyte via its typical behaviour at high salinity. Shoot growth of cultivated barley was gradually reduced with increasing salinity, whereas that of wild barley was enhanced at 100 and 200 mm NaCl then slightly reduced at 300 mM NaCl. The higher salt tolerance of H. maritimum as compared to H. vulgare was due to its higher capacity to maintain cell turgor under severe salinity. Furthermore, H. maritimum exhibited fine regulation of Na+ transport from roots to shoots and, unlike H. vulgare, it accumulated less Na+ in shoots than in roots. In addition, H. maritimum can accumulate more Na+ than K+ in both roots and shoots without the appearance of toxicity symptoms, indicating that Na+ was well compartmentalized within cells and substituted K+ in osmotic adjustment. The higher degree of salt tolerance of H. maritimum is further demonstrated by its economic strategy: at moderate salt treatment (100 mm NaCl), it used inorganic solutes (such as Na+) for osmotic adjustment and kept organic solutes and a large part of the K+ for metabolic activities. Indeed, K+ use efficiency in H. maritimum was about twofold that in H. vulgare; the former started to use organic solutes as osmotica only at high salinity (200 and 300 mm NaCl). These results suggest that the differences in salt tolerance between H. maritimum and H. vulgare are partly due to (i) differences in control of Na+ transport from roots to shoots, and (ii) H. maritimum uses Na+ as an osmoticum instead of K+ and organic solutes. These factors are differently reflected in growth. 相似文献