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1.
Effects of NaCl on the seed germination and growth of Casuarina equisetifolia seedlings and multiplication of the Frankia Ceq1 strain isolated from the root nodules of C. equisetifolia were examined. The germination rate of the seeds markedly decreased as the NaCl concentration increased and germination did not occur at 300 mM NaCl. The fresh weight of both shoots and roots of the seedlings treated with NaCl for 6 weeks apparently decreased as the NaCl concentration increased. However, root nodules were formed by inoculation with the Frankia Ceq1 strain in some seedlings treated with 300 mM NaCl and the viability of the seedlings at 500 mM NaCl was almost the same as that of the seedlings not subjected to the NaCl treatment. The Na+ concentration in the shoots sharply increased with the elevation of the NaCl concentration in the ambient solution, but the level was approximately 300 mM even in the seedlings treated with 500 mM NaCl for 6 weeks. On the other hand, the increase of the Na+ concentration in the roots by the NaCl treatment was much smaller than that in the shoots and the level was less than 150 mM. The growth of the free-living Frankia Ceq1 strain was approximately linearly suppressed as the NaCl concentration in the medium increased and the hyphae became somewhat thicker and shorter or disintegrated in the medium containing NaCl at a concentration above 150 mM. The Na+ concentration in the cells increased as the NaCl concentration in the medium increased, but the level was maintained at less than 30 mM even in the medium containing 500 mM NaCl. The cells whose growth was suppressed by the NaCI treatment grew actively again at almost the same rate as the control cells (not subjected to the NaCl treatment) when they were transferred to NaCl-free medium. These results strongly suggested that both C. equisetifolia seedlings and Frankia Ceq1 strain are highly tolerant to salt and this symbiotic system is useful for the recovery of the vegetation in areas with severe salt accumulation.  相似文献   

2.
The resistance of most plants to salt can be impaired by concurrent waterlogging. However, few studies have examined this interaction during germination and early seedling growth and its implications for nutrient uptake. The aim of the study was to examine the response of germination, early growth, and nutrient uptake to salt (NaCl) and hypoxia applied to barley (Hordeum vulgare L. cv. Stirling), in solution culture. Hypoxia, induced by covering seeds with water, lowered the germination from 94% to 28% but salinity and hypoxia together lowered it further to 13% at 120 mM NaCl. While the germination was 75% at 250 mM NaCl in aerated solution, it was completely inhibited at this NaCl concentration under hypoxia. Sodium ion (Na+) concentrations in germinated seedlings increased with increasing salinity under both aerated and hypoxic conditions during germination, while K+ and Mg+ concentrations were decreased with increasing salinity in 6 d old seedlings. After 20 d, control seedlings had the same dry weights of the roots and shoots with and without hypoxia but at 10 mM NaCl and higher, shoot and root dry weight was depressed with hypoxia. Sodium ion increased in roots and shoots with increased NaCl under both aerated and hypoxic conditions while K+ was depressed when salinity and hypoxia were applied together and Ca2+ was mostly decreased by NaCl. In general, hypoxia had greater effects on nutrient concentrations than NaCl by decreasing N, P, S, Mg, Mn, Zn, and Fe in shoots and by increasing B concentrations. The threshold salinity levels decreased markedly for germination, uptake of a range of nutrients, and for seedling growth of barley under hypoxic compared to well‐aerated conditions.  相似文献   

3.
The effects of calcium and humic acid on seed germination, growth and macro- and micro-nutrient contents of tomato (Lycopersicon esculentum L.) seedlings in saline soil conditions were evaluated. Different levels of humic acid (0, 500, 1000 and 2000 mg kg?1) and calcium (0, 100, 200 and 400 mg kg?1) were applied to growth media treated with 50 mg NaCl kg?1 before sowing seeds. Seed germination, hypocotyl length, cotyledon width and length, root size, shoot length, leaf number, shoot and root fresh weights, and shoot and root dry weights of the plant seedlings were determined. Macro- and micro-nutrient (N, P, K, Ca, Mg, S, Cu, Fe, Mn and Zn) contents of shoot and root of seedlings were also measured. Humic acid applied to the plant growth medium at 1000 mg kg?1 concentration increased seedling growth and nutrient contents of plants. Humic acid not only increased macro-nutrient contents, but also enhanced micro-nutrient contents of plant organs. However, high levels of humic acid arrested plant growth or decreased nutrient contents. Levels of 100 and 200 mg kg?1 Ca2+ application significantly increased N, Ca and S contents of shoot, and N and K contents of root.  相似文献   

4.
The aim of this study was to determine the influence of selected halotolerant endophytic bacteria isolated from the roots of Salicornia europaea on the growth parameters of Beta vulgaris under different concentrations of salinity. Two endophytic strains were selected as inocula for the pot experiment: Pseudomonas sp. ISE-12 (B1) and Xanthomonadales sp. CSE-34 (B2). Surface-sterilised seeds were incubated in the bacterial inoculation suspensions before sowing and cultivated in a sterile mixture of sand and vermiculite (1:1). Six salinity treatments were taken into account: 0, 50, 100, 150, 200 and 300 mM NaCl. Inoculation of seeds with B1 and B2 positively affected germination percentage and germination index and shortened mean germination time, which led to a quickening of the growth stages of seedlings. After 42 days inoculated plants had, in general, a greater root length, higher dry biomass, lower tissue water content and lower specific leaf area compared with the control. While the positive effect of B2 bacteria was visible only at low salinity, strain B1 stimulated plant growth at higher salinities (200 and 300 mM NaCl). We suggest that the superior growth promotion observed for B1 may be related to the higher metabolic activity of these bacteria.  相似文献   

5.
Abstract

Sunflower seeds (Helianthus annutis L. cv. Dwarf) were grown only with increasing saline solutions [0, 50, and 100 mM sodium chloride (NaCl)] and potassium (K) supply to determine how salinity and K supply will affect plant germination and growth. Potassium supply under highly saline conditions (100 mM) or nonsaline conditions had a beneficial effect on sunflower seedlings germination which was not significantly altered with moderate salt concentrations (50 mM). During the stage studied, K supply in the absence of salinity increased significantly seedling biomass which reflects what is happening in the aerial part and root. This increase was proportionally higher in the stem than in the leaf with no variations in the foliar surface. In a saline environment, K supply did not markedly alter plant dry matter production, but increased foliar surface with moderate salt concentrations (50 mM) in the root environment.  相似文献   

6.
In this study, the first experiment analyzed the effects of 0, 85, 171, 256, and 342 mM sodium chloride (NaCl) on the germination of Acacia seyal seeds. In the second in vitro experiment, the effects of inoculation with two rhizobial strains on growth, physiological, and biochemical responses of A. seyal seedlings was evaluated at four levels (0, 85, 171, and 256 mM) of NaCl. Results showed that at 342 mM NaCl, germination rate of A. seyal seeds declined by 56% from the control value, while any germination was recorded for Acacia bivenosa and Acacia sclerosperma seeds at the same salt level. Salt stress gradually decreased the growth, the soluble protein and the leaf-chlorophyll contents of A. seyal seedlings. However, rhizobial inoculation limits these adverse effects of salt on physiological and metabolic processes responses. A. seyal exhibited a moderate halophytic behavior; nodulation was enhanced by moderate salt stress.  相似文献   

7.
The impact of salinity (0–400 mM NaCl) on the germination of four Tunisian accessions (Tabarka, Mahdia, Sfax, and Jerba) of the halophyte Cakile maritima was assessed. Moderate salinity (50–150 mM NaCl) slightly inhibited the germination of Sfax, Mahdia, and Jerba seeds, since more than 75% of the sown seeds germinated. Salt adverse impact was more pronounced in Tabarka seeds, which showed significantly less germination capacity, even under salt‐free conditions (40%). Although increasing salinity drastically inhibited the germination in Tabarka, Sfax was the most tolerant accession, especially at 200–300 mM sodium chloride (NaCl). Assessing germination kinetics using a mathematical model indicated that high salinity impaired and delayed the germination process. Such an effect resulted from the combination of osmotic and toxic components, especially at the greatest concentrations (300–400 mM NaCl). These findings point out that the successful establishment of this halophyte at the earliest ontogeny stages is both accession‐ and salt‐dependent.  相似文献   

8.
Abstract

The effects of pretreatment with salicylic acid on wheat seed germination (Triticum aestivum L. cv. Roshan), lipid peroxidation, and superoxide dismutase, catalase, polyphenol oxidase, and peroxidase activity were studied under conditions of salt stress. Seeds treated with different concentrations of salicylic acid were used for measuring germination traits. Salt stress was induced by sodium chloride solution. Seeds were soaked in salicylic acid solution for 24 h, dried with sterile paper, transferred to sterile Petri dishes, and treated with 10 ml NaCl solution at different concentrations. After 1 week, the number of germinated seeds, root length, seedling length, and dry weight were recorded. Antioxidant enzyme activity and lipid peroxidation were also assayed. Salinity decreased seed germination. Thus, a high concentration of NaCl (200 mM) decreased germination by 17.6% compared with control treatment. Salicylic acid significantly increased germination in stressed and control seeds. Salicylic acid increased the level of cell division of seedlings and roots, which increased plant growth. Salt stress significantly increased the activity of the antioxidative enzymes catalase, superoxide dismutase, peroxidase, and polyphenol oxidase in wheat seedlings, and salicylic acid reduced the activity of antioxidant enzymes as stress signal molecules. Our results indicated that scavenging of reactive oxygen species was effective, especially by salicylic acid, and that membrane damage was limited. The aim of the present work was to study the character of changes in enzymatic systems induced by NaCl and salicylic acid in wheat seedlings under conditions of salt stress. In brief, salicylic acid treatment reduced the damaging action of salinity on embryo growth and accelerated a restoration of growth processes; thereupon it may be effective for the improvement of seed germination in arid and semi-arid regions.  相似文献   

9.
《Journal of plant nutrition》2013,36(8):1441-1452
Abstract

Saltgrass [Distichlis spicata (L.) Greene var. stricta (Gray) Beetle], accession WA-12, collected from a salt playa in Wilcox, AZ, was studied in a greenhouse to evaluate its growth responses in terms of shoot and root lengths, shoot dry-matter yield, and nitrogen (N) (regular and 15N) absorption rates under control and salt (sodium chloride, NaCl) stress conditions. Plants were grown under a control (no salt) and three levels of salt stress (100, 200, and 400 mM NaCl, equivalent to 5850, 11700, and 23400 mg L? 1 sodium chloride, respectively), using Hoagland solution in a hydroponics system. Ammonium sulfate [(15NH4)2SO4], 53% 15N (atom percent 15N) was used to enrich the plants. Plant shoots were harvested weekly, oven-dried at 60°C, and the dry weights measured. At each harvest, both shoot and root lengths were also measured. During the last harvest, plant roots were also harvested and oven-dried, and dry weights were determined and recorded. All harvested plant materials were analyzed for total N and 15N. The results showed that shoot and root lengths decreased under increasing salinity levels. However, both shoot fresh and dry weights significantly increased at 200 mM NaCl salinity relative to the control or to the 400 mM NaCl level. Shoot succulence (fresh weight/dry weight) also increased from the control (no salt) to 200 mM NaCl, then declined. The root dry weights at both 200 mM and 400 mM NaCl salinity levels were significantly higher than under the control. Concentrations of both total-N and 15N in the shoots were higher in NaCl-treated plants relative to those under the control. Shoot total-N and 15N contents were highest in 200 mM NaCl-treated plants relative to those under the control and 400 mM salinity.  相似文献   

10.
Abstract

A pot culture experiment with four levels of soil moisture (40, 55, 70, and 85% of field capacity) and five levels of sodium chloride (NaCl) concentration (0, 50, 100, 150, and 200 mM) in soil was conducted to examine the interactive effect of soil moisture and NaCl on the growth of halophyte Suaeda salsa. Results showed that growth was largest at 55% of field capacity, in the range of 50–100 mM NaCl. However, at 85% of field capacity, it can grow better at higher salinity levels; and at 40% of field capacity, the growth of S. salsa was increased greatly by moderate salinity. Contents of sodium (Na) and chloride (Cl) in plant tissues increased with the decrease of moisture levels of soil. Potassium (K) concentrations were also increased at low soil moisture. Drought tolerance was increased by moderate NaCl concentrations. It is thus considered that some amounts of Na and Cl are required to absorb water in this plant.  相似文献   

11.
Abstract

Two experiments were conducted. The first was to study nodulation and N2fixation of several introduced alder species (Alnus glutinosa, A. incana, A. rubra, and A. viridis) grown in soil from beneath Alnus orientalis. The second was to determine pattern of nitrogen (N) changes in leaves and bark of Alnus orientalis and Populus nigra natural stands during two successive years. Results showed that Frankia in soil from underneath Alnus orientalis nodulated and fixed nitrogen on roots of local alder as well as on roots of introduced alder species from distant and ecologically diverse localities. However, differences were found among species in the number of nodules formed and amount of nitrogen fixed. Percentages of nitrogen derived from atmosphere (%Ndfa) ranged from 5% in A. viridis to 66% in A. orientalis. Microscopic study of Alnus orientalis nodules showed the presence of vesicles, and Frankia belonging to Sp type. Foliar N concentration was higher in alder than in poplar. Total N concentration in alder leaves remained relatively constant at about 3% during summer, whereas N concentration in poplar decreased sharply in leaves and increased in bark. No substantial increase in N concentration was found in alder bark, and the fallen leaves were rich in N. During autumn, leaf N concentrations in poplar decreased by 43% and 51% for the first and the second year, respectively; whereas N concentrations in bark increased by 71 % and 100%. Total N concentrations in alder leaves decreased only by 8–16% while, values in the adjacent bark remained stable. In contrast to poplar, it seems that Alnus orientalis does not exhibit net leaf retranslocation to bark tissues.  相似文献   

12.
Growth and micronutrient acquisition of some apple (Malus dometsica Borkh) varieties (Galla, MM 111, MM I06, M 26, and M6 York) were studied under gradually in vitro induced NaCl (from 0, 50 to 100 mM) salinity. Microshoot dry weight tended to increase with increasing salinity level in all varieties except in M 26 and M6 York as some decline was obtained at 100 mM NaCl. Shoot proliferation was decreased significantly in Galla at 100 mM NaCl and at both salinity levels in M 26 compared to the control (0 mM). A significant decrease in shoot zinc (Zn) acquisition with increasing salinity level was obtained in all varieties except MM 111. M6 York and MM 111 decreased their copper (Cu) acquisition significantly at 50 mM NaCl and then increased at 100 mM salinity level. Meanwhile, a significant decrease in Cu acquisition with increasing NaCl concentration was obtained in Galla and M 26. Galla, MM 106, and M 26 showed a significant increase in manganese (Mn) acquisition at 50 mM NaCl followed by a decrease at 100 mM salinity level. On the other hand, Mn acquisition continued to decrease significantly in MM 111 while M6 York increased its Mn acquisition with increasing salinity. M 111 and M6 York showed a significant decrease in iron (Fe) acquisition at 50 mMNaCl followed by an increase at 100mM NaCl. Galla and M 26 continued to decrease Fe acquisition with elevated salinity level, whereas Fe in MM 106 increased with salinity.  相似文献   

13.
□ Growth and nutrient acquisition of tomato (Lycopersicon esculentum L.) cv ‘Amani’ were studied under induced salt stress in Hoagland's solution. The plants were treated for 37 days with salinity induced by incorporating different concentrations [0.0 (control), 50, 100, 150, or 200 mM] of sodium chloride (NaCl) to the nutrient solution. Slight reduction was obtained in growth represented by (shoot length and number, leaf number, and dry weight) when seedlings were directly exposed to NaCl stress from 0.0 to 100 mM. At higher concentrations (150 or 200 mM), growth parameters were adversely affected and seedlings died thereafter. Elevated salinity significantly reduced crude protein and fiber in shoots and roots. Tomato shoot and root contents of potassium (K), iron (Fe), and ash were reduced significantly in response to increased levels of salinity. Tissue contents of sodium (Na) and chloride (Cl) increased with elevated salinity treatments.  相似文献   

14.
Abstract

The effects of three levels of salinity [0, 50, and 100 mM of sodium chloride (NaCl)] and the addition of potassium, calcium, nitrogen, phosphorus, iron, manganese, and boron (K, Ca, N, P, Fe, Mn, and B) on seed germination and survival of Helianthus annuus L. plants grown in an inert medium were studied. Increasing levels of salinity significantly decreased germination percentage. The presence of NaCl affected seedling survival rather than germination. Nitrogen addition damaged seedling growth, especially in high saline conditions. Addition of some nutrients may alleviate the effects induced by NaCl. Calcium additions to the culture medium significantly improved germination percentage and seedling survival, which markedly decreased after addition of K and B under saline conditions. Iron addition, especially in the ferrous form, counteracted the effects of salinity on seed germination and seedling survival. Phosphorus addition showed detrimental effects on germination and especially in seedling survival; however, it benefited the surviving seedling's growth.  相似文献   

15.
ABSTRACT

The present work was aimed at determining the limits of tolerance to sodium chloride (NaCl) of a halophyte, Beta macrocarpa Guss (wild Swiss chard). Five week-old plants were cultivated with a nutritive solution to which was added 0, 100, 200, and 300 mM NaCl. Plants were harvested after four weeks of treatment. The growth (fresh and dry weight, leaf surface area, and leaf number), water contents, and the mineral composition (meq · g?1 DW) of roots and leaves (reduced nitrogen (N), K+, Ca2 +, Na+, Cl?) were determined on individual plants. Results show that Beta macrocarpa can tolerate up to 200 mM NaCl. A significant decrease in biomass production (to 50% of control) was observed only for 300 mM NaCl. In the latter treatment, leaf mean surface area was 25% of control. The shoot-to-root ratio was not changed. Leaf hydration was not modified by salt treatment. This ability of the plant to maintain the hydric equilibrium of its leaves seemed associated with an efficient intracellular compartmentalization of Na+ and Cl? ions. Salt treatment had little effect on N content (80% of control), but decreased significantly K+ and Ca2 + contents. These three essential elements could be limiting for growth of leaves and roots of plants challenged by NaCl.  相似文献   

16.
The shoot and root growth response of three species of Sesbania to 0, 50 and 100 mM NaCl in a hydroponic culture was studied. Absorption and translocation of Na and Cl in 15 day old seedlings were studied using 22Na and 36Cl labelled NaCl. Shoot growth was significantly reduced at 100 mM NaCl in the nutrient solution for all three species. The salt tolerance of the three species was in the order S. rostrata > S. aculeata > S. speciosa. The transport of Na to stem and leaf was less compared to uptake in S. rostrata but greater proportion of the absorbed Cl was translocated to the shoot. Salinity reduced the nitrogen content in root and stem significantly.  相似文献   

17.
Abstract

Salinity is one of the serious abiotic stresses that has adverse effects on plant growth. The aim of this study was to investigate the effect of sodium chloride (NaCl) on germination and growth parameters of tomato plant as well as the role of Ca2+as an ameliorating agent. 100?mM NaCl and two concentrations of calcium (5 and 10?mM) were applied to tomato seeds and seedlings. This study was carried out in a Completely Randomized Design (CRD) with a total of six treatments each comprising of three replicates. The application of 100?mM of NaCl delayed the germination time by 27.6%, reduced the seedling length and seedling vigor by 24.33% and germination stress tolerance by 27.6% as compared to control. Salinity also reduced the plant growth (root and shoot length, root fresh and dry weight, shoot fresh and dry weight, membrane stability, relative water content and leaf area), whereas the application of calcium mitigated the negative effects of salinity on germination and growth to a greater extent. With increased calcium concentration, growth and germination increased significantly both alone and in the salt-affected plant. 10?mM calcium showed best results and enhanced the promptness index by 20.7%, seedling length and vigor by 15.1% and GSI by 20.7%. It also improved root fresh and dry weight, shoot fresh and dry weight, relative water content and leaf area. Similarly, 5?mM calcium also increased plant height and membrane stability index. The present study suggests that application of Ca2+ enhanced the growth of tomato plant under saline conditions.  相似文献   

18.
The present study was conducted to investigate the effects of Zn application to salt stressed eggplant (Solanum melongena L.) seedlings grown in vitro and whether it can alleviate the deleterious effects of salinity or not. Zinc (0, 5, 10 and 20?mg/L) and sodium chloride (NaCl) at different concentrations (0, 50, 100 and 150?mM) were added to solidified half strength MS medium placed in 250?mL glass jars. The treatments were arranged in a 4?×?4 factorial experiment in a completely randomized design with four replications. Application of Zn to growing seedlings at different concentrations (5, 10 or 20?mg/L) increased the length of shoot and root and their dry weights, as well as enhanced the photosynthetic pigment contents and leaf relative water content compared to control. However, the application of NaCl to growing seedlings at different concentrations (50, 100 and 150?mM) significantly reduced the above mentioned attributes compared to control and those of Zn treatments alone. Treatment of seedlings with either Zn (5, 0 or 20?mg/L) or NaCl (50, 100 or 150?mM) significantly increased the proline content and the antioxidant enzyme activities of superoxide dismutase (SOD), peroxidase (POX) and ascorbate peroxidase (APX) in growing seedlings. However, the application of Zn to salt stressed seedlings mitigated the deleterious effects of salt stress in growing seedlings and increased the tolerance of seedlings to its deleterious effects.  相似文献   

19.
Soil management through the cultivation of salt-tolerant plants is a practical approach to combat soil salinization. In this study, salt tolerance of 35 barley (Hordeum vulgare L.) genotypes was tested at four salinity levels (0, 100, 200, and 300 mM NaCl in Hoagland nutrient solution) at two growth stages (germination and vegetative). The relationship between salinity tolerance and carbon isotope discrimination (CID) was also accessed. Results of the study carried out under laboratory conditions showed that a negative linear relationship was observed between salt concentration and germination as well as other growth parameters. Some genotypes showed good salt tolerance at germination but failed to survive at seedling stage. However, five genotypes, namely, Jau-83, Pk-30109, Pk-30118, 57/2D, and Akermanns Bavaria showed better tolerance to salinity (200 mM) both at germination and at vegetative growth stage. The salt tolerance of these barley genotypes was significantly correlated with minimum decrease in K+:Na+ ratio in plant tissue with increase in the root zone salinity. However, the case was reversed in sensitive genotypes. CID was decreased linearly with increase in root zone salinity. However, salt-tolerant genotypes maintained their turgor by osmotic adjustment and by minimum increase in diffusive resistance and showed minimum reduction in CID (Δ) with gradual increase in rooting medium salt concentration. Results suggested that the tolerant genotypes make osmotic adjustments by selective uptake of K+ and by maintaining a higher K+:Na+ ratio in leaves. Moreover, CID technique can also be good criteria for screening of salt-tolerant germplasm.  相似文献   

20.
Abstract

Effects of silicon (Si) priming at 0, 0.5, 1.0, and 1.5?mM on germination, ion balance, and root structure of two durum wheat cultivars at 0, 100, and 200?mM sodium chloride (NaCl) was conducted in a laboratory. An aliquot of 200?mM NaCl with 1.5?mM Si improved Behrang cultivar germination from 54 to 88%, but in Yavaros only from 49 to 85%. In Behrang, the control root length at 200?mM NaCl increased from 5.07 to 7.11?mm when treated with 1.5?mM Si, but Yavaros only increased from 3.18 to 4.09?mm. Behrang accumulated less sodium (Na+) and more potassium (K+). For mean diameter of central and peripheral metaxylem cells, Behrang benefitted more from Si amelioration than Yavaros. Salinity affected the diameter of central and peripheral metaxylem cells to a greater degree compared to vessel number. Si soil application (1.0 and 1.5?mM Si) may help to establish durum wheat seeds grown under saline conditions.  相似文献   

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