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1.
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.  相似文献   

2.
Fern leaf lavender (Lavandula multifida L.) is a perennial shrub native to Almería with known medicinal properties, which grows in saline soils that are increasingly present in the Mediterranean region. However, the effects of salinity on the mineral nutrition and physiology of L. multifida are unknown. In the present study, we evaluated the salt resistance of this species and compared it with other members of the Lamiaceae . Plants of L. multifida were grown in pots in a mixture of sphagnum peat‐moss and Perlite, and treated with five different NaCl concentrations [10 (control), 30, 60, 100, and 200 mM NaCl] over a period of 60 d. The effects of different levels of salinity on mineral nutrient and osmolyte concentrations and on biomass were evaluated. Our results show that L. multifida plants were able to grow with 60 mM NaCl without significant biomass reduction. Na+ and Cl− were the main contributors to the osmotic potential in both roots and leaves, whereas total soluble sugars (TSS) and proline made only a small contribution. The concentrations of TSS and proline showed different trends in the different organs: in roots, both showed the highest concentrations at 60 mM NaCl, whereas in leaves TSS increased and proline decreased with increasing salt stress. To survive salinity, L. multifida plants increased salt excretion (Na+ and Cl−) by leaves at 100 and 200 mM NaCl and leaf succulence at 60, 100, and 200 mM NaCl. Excessive accumulation of Na+ and Cl− was avoided by shedding leaves. Our results indicate that L. multifida is better adapted to salinity compared to other members of the Lamiaceae ¸ a consideration that is particularly relevant for their growth in arid saline areas.  相似文献   

3.
Cucumber (Cucumis sativus L. cv. Lvyuan4) seedlings were either noninoculated or inoculated with four bacteria to study the interactions of salinity in saline soil, cucumber, and bacteria. The seedlings were grown under controlled conditions in pots; the solutions of 100, 200, 400, and 600 mM sodium chloride (NaCl) and bacterial broth were added to the soils. Deionized water was used as control. There were nine treatments in the experiment. Each treatment contained three replications and each replication represented six plants. After 14 days of treatment, morphological characteristics, fresh and dry weights, chlorophyll, soluble sugar, malonaldehyde, proline, nutrient elements, and sodium (Na+) and chloride (Cl?) contents in plants and soils were calculated. Soil salinity inhibited seedlings growth, but low concentration of NaCl promoted plant growth. Soil microbial biomass decreased in saline soils and increased in inoculated treatments. Bacteria had the role of promoting growth and protecting plants against salinity. Bacteria accelerated Na+ and Cl? uptake markedly.  相似文献   

4.
Abstract

The turf grass Pennisetum clandestinum Hochst. (kikuyu grass) is one of the candidate plants for utilization and reclamation of salinized areas. The capability of kikuyu grass to grow under saline conditions was tested during 6 months, under various irrigation treatments (tap water control, 80‐mM, 150‐mM, 200‐mM, 240‐mM NaCl). Plant biomass production was visibly affected only at NaCl concentrations greater than 150‐mM NaCl. Plant growth and plant regeneration capability in the 200‐ and 240‐mM NaCl treatments gradually decreased as the experiment progressed in time. The photosynthetic potential of the plants remained unchanged and was neither affected by the treatment nor with time. Proline content of leaves as well as the content of Na+ and Cl? increased with increasing salinity stress. Apparently, kikuyu grass can withstand moderate concentrations of NaCl for prolonged periods and under repeated mowing. Thus, this grass can be used as a potential ground cover and as fodder grass in saline habitats.  相似文献   

5.
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6.
Abstract

The effect of two different levels of salinity upon adult plants of Digitalis purpurea has been studied. Seeds of D. purpurea plants were sown in pots of equal size and moistened with deionized water during one year. Afterwards, different treatments with NaCl were initiated, the concentrations being 100 mM and 200 mM NaCl in irrigation water during 63 days. Growth, measured as dry and fresh weight, and soluble protein contents, were lower in stressed plants than in control plants. Monovalent cation analysis showed that in leaves K+ plus Na+ (Total M) values did not change with the different treatments, but that in roots these values increased with the increasing salinity stress. On the other hand, proline levels were higher in stressed plants although the accumulation of this amino acid was not significant In leaves, Cl? levels increased linearly with salinity degree, and the accumulation of this ion was faster than that of Na+, whereas in roots, the Cl? level remained relatively low.

Total cardenolide levels in leaves and roots of the 100 mM NaCl plants were higher than those in 200 mM NaCl and control plants. We infer that moderate salinity conditions lead to raised cardenolide levels, principally in leaves, but the reason for this is not clear.  相似文献   

7.
We studied the growth and ionic composition of five wheat genotypes (Inqlab-91, Uqab 2002, SARC-1, SARC-3, and SARC-5) grown under salinity stress to applied silicon. Plants were grown with three levels of salinity [0, 60, and 120 mM sodium chloride (NaCl)] in the presence of 0, 2, and 4 mM Si in nutrient solution for 40 days. Salinity stress significantly decreased shoot and root biomass in plants with varying degrees. Genotype SARC-3 exhibited higher salt tolerance than other genotypes. Silicon (Si) application significantly (P < 0.05) increased plant biomass at both control as well as under saline conditions. Genotypes differed significantly for their response to applied Si in terms of biomass production. Silicon application significantly (P < 0.01) increased potassium (K+) concentration in shoots. Enhanced salinity tolerance in wheat by Si application was attributed to increased K+ uptake thereby increasing K+/sodium (Na+) ratio and lower Na+ translocation towards shoot.  相似文献   

8.
《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   

9.
Salinity is one of the most important agricultural problems in Iran. The effect of different levels of salinity and phosphorus on shoot length, root and shoot fresh and dry weight, nutrient elements (sodium (Na+), potassium (K+), phosphorus (P) and chloride (Cl?), proline and soluble sugar contents of barley were investigated. Two cultivars of barley, Hordeum murinum (wild resistant germplasm) and Hordeum vulgar, variety Afzal were treated in vegetative stage under hydroponics condition in a factorial arrangement based on completely randomized block (CRB) design with four levels of salinity [0, 100, 200 and 300 mM sodium chloride (NaCl)] and three levels of phosphorus (15, 30 and 55 μm L?1) with three replications. By increasing salinity, all the measured parameters, except sodium (Na+) content were reduced. Furthermore, with increased in phosphorus levels from 15 to 55 μm, Na+ content of the plant shoots decreased, but length, fresh and dry weights of roots and shoots and K+, P, Cl?, proline, and soluble sugars content of the shoots increased. The results indicated that accumulation of mineral ions for osmotic adjustment and restriction of Na+ accumulation in shoots were involved in phosphorus enhancement of the salt tolerance of barley. Thus, it seems that in saline soils, where there is no possibility for soil leaching and amending, application of phosphorus fertilizers can lead to a satisfactory growth and production in barely yield.  相似文献   

10.
Drip irrigation offers potential for rice (Oryza sativa L.) production in regions where water resources are limited. However, farmers in China’s Xinjiang Province report that drip-irrigated rice seedlings sometimes suffer salt damage. The objective of this study was to learn more about the effects of soil salinity and soil temperature on the growth of drip-irrigated rice seedlings. The study consisted of a two-factor design with two soil salinity treatments (0 and 1.8 g kg?1 NaCl) and three soil temperature treatments (18°C, 28°C and 36°C). The results showed that shoot biomass, root biomass and root vigor were greatest when seedlings were grown with no salt stress (0 g kg?1 NaCl) at 28°C. Moderate salt stress (1.8 g kg?1 NaCl) combined with high temperature (36°C) significantly reduced root and shoot biomass by 39–53%. Moderate salt stress and high temperature also increased root proline concentration by 77%, root malonyldialdehyde concentration by 60% and seedling mortality by 60%. Shoot and root Na+ concentrations, shoot and root Na+ uptake and the Na+ distribution ratio in shoots were all the greatest when moderate salt stress was combined with high temperature. In conclusion, high soil temperature aggravates salt damage to drip-irrigated rice seedlings. Therefore, soil salinity should be considered before adopting drip-irrigation for rice production.  相似文献   

11.
Sesuvium portulacastrum is a dicotyledonous halophyte. The responses of different clones of Sesuvium to salinity were analysed by measuring changes in growth, biomass accumulation, water content, osmolytes accumulation, oxidative damage, antioxidant enzymes and inorganic ions. In addition, microscopic observations were made to discern any changes in the stem anatomy of Sesuvium under salt stress. Reduced growth, biomass accumulation and tissue water content correlated with an increase in NaCl concentrations (200–800 mM), except at 200 mM NaCl, where an improvement in the parameters was observed among all clones, specifically in MH1 (Maharashtra). Increased osmolytes (proline, glycine betaine and total soluble sugars) and the accumulation of Na+ ions, without affecting K+content, were recorded in all clones. Higher malondialdehyde content and greater relative electrolyte leakage were evident in addition to increased catalase and superoxide dismutase activities under salt stress. Increased cortical cell size and cortex diameter of the stem were observed upon 200–400 mM NaCl stress; decreased thickness was seen at higher NaCl concentrations. This study suggests the differential behaviour of Sesuvium clones which might be useful in the rapid selection of a potent clone (such as MH1) for the restoration of wetlands and desalination of saline soils.  相似文献   

12.
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   

13.
Physiological responses to salt stress were investigated in two cotton (Gossypium hirsutum L.) cultivars (Pora and Guazuncho) grown hydroponically under various concentrations of NaCl. Dry matter partitioning, plant water relations, mineral composition and proline content were studied. Proline and inorganic solutes were measured to determine their relative contribution to osmotic adjustment. Both leaf water potential (Ψw) and osmotic potential (Ψs)decreased in response to NaCl levels. Although Ψwand Ψs decreased during salt stress, pressure potential Ψp remained between 0.5 to 0.7 MPa in control and all NaCl treatments, even under 200 mol m?3 NaCl. Increased NaCl levels resulted in a significant decrease in root, shoot and leaf growth biomass. Root / shoot ratio increased in response to salt stress. The responses of both cultivars to NaCl stress were similar. Increasing salinity levels increased plant Na+ and Cl?. Potassium level remained stable in the leaves and decreased in the roots with increasing salinity. Salinity decreased Ca2+ and Mg2+ concentrations in leaves but did not affect the root levels of these nutrients. The K/Na selectivity ratio was much greater in the saline treated plants than in the control plants. Osmotic adjustment of roots and leaves was predominantly due to Na+ and Cl? accumulation; the contribution of proline to the osmotic adjustment seemed to be less important in these cotton cultivars.  相似文献   

14.
In the course of investigations on the impact of salinity on mineral ion transport in differentially salt susceptible soybeans (“Lee” and “Jackson”) short-term experiments were conducted to elucidate the distribution pattern of Na+ and some other cations. The results showed that low salinity (7.5 mM NaCl) did not induce varietal differences in Na+ content during a 30 hrs uptake period. At 66.5 mM NaCl, however, the Na+ contents increased more in the leaves of the salt sensitive variety “Jackson” than in “Lee”. Both soybean varieties retained Na+ in the proximal root and stem. Furthermore, they extruded considerable amounts of Na+ from the roots to the medium. Increasing the level of salinity in the solution substantially reduced the Ca2+ uptake of both soybean varieties. In an experiment with the salt sensitive variety under constant salinity but increasing Ca2+ concentration in the medium, the plants showed a reduction in Na+ uptake and translocation to stem and leaves and an enhanced Ca2+ uptake and translocation to the shoots. It is suggested that the injury observed in “Jackson” after salt treatment is not only related to the insufficient control of Cl? transport. At higher salinity levels the increasing accumulation of Na+ in the leaves and the varietally independant depression of Ca2+ uptake and translocation may enhance the development of leaf necrosis.  相似文献   

15.
Maize (Zea mays L.) plants in the early stage of development were treated with 80 mM sodium chloride (NaCl) with or without supplemental calcium (Ca2+) (8.75 mM) for a seven day period. The effects of salinity on dry matter production and shoot and root concentrations of sodium (Na+), Ca2+, and potassium (K+) were measured for seven Pioneer maize cultivars. Salinity significantly reduced total dry weight, leaf area, and shoot and root dry weight below control levels. For all seven cultivars, Na+concentrations were reduced and leaf area was significantly increased by supplementing salinized nutrient solutions with 8.75 mM calcium chloride (CaCl2). The two cultivars with the lowest shoot and root Na+ concentrations under NaCl‐salinity showed the greatest increases in total, shoot and root dry weights with the addition of supplemental Ca. Shoot fresh weight/dry weight ratios for all cultivars were decreased significantly by both salinity treatments, but supplemental Ca2+ increased the ratio relative to salinity treatments without supplemental Ca. Root fresh weight/dry weight ratios were decreased only by salinity treatments with supplemental Ca. With NaCl‐salinity, cultivars which had lower shoot and root Na+ concentrations were found to be more salt sensitive and had significantly lower amounts of dry matter production than those cultivars which had higher shoot and root Na+ concentrations. It was concluded that Na+ exclusion from the shoot was not correlated with and was an unreliable indicator of salt tolerance for maize.  相似文献   

16.
Abstract

The time sequence of uptake and distribution of labelled Na and Cl– in osmotically adjusted “Kallar”; grass was studied at low (10 mM) and moderately high salinity (100 mM) in nutrient solutions. Increasing NaCl raised the concentrations of Na+ and Cl– in the tissue of tops and roots but had little or no effect on plant growth. On the leaves no toxic symptoms were obvious, not even in plants grown at salt stress of 200 mM NaCl. In all treatments, the young and the old leaves extruded 30–60% and 30–70% of their total Na+ and Cl–. As the amounts of Na+ and Cl– in the tissue increased with time, their extrusion also increased, however, as a proportion of the total Na+ and Cl– it did not change much with time. Autoradiographs revealed that the extruded salts were distributed equally on the upper and lower surface of all leaves, parallel to veins. There seemed to be a more intense distribution of Na+ and Cl– in the leaf sheaths as well as in the apical region of the roots. However, the net transfer rates, even after only 6 hours of uptake, did not indicate a strong retention mechanism in the roots.  相似文献   

17.
To investigate the influence of potassium (K+) on the salinity tolerance of Chinese cabbage (Brassica pekinensis Rupr.) seedlings, the plants were cultured at three K+ levels (0, 5, or 10?mM), under normal (0?mM NaCl) and high-salt (100?mM NaCl) conditions. The results indicated that the dry weight of Chinese cabbage increased with the application of K+ under salt stress. Addition of K+ increased K+ concentrations and suppressed sodium (Na+) concentration, which eventually increased the K+/Na+ ratios in roots or shoots. Application of K+ enhanced the uptake of K+ and suppressed the uptake of Na+. Moreover, the ratios of shoot-K+/root-K+ increased considerably, but the ratios of shoot-Na+/root-Na+ decreased in response to K+ application. It was concluded that the application of K+ could enhance the salt stress tolerance in Chinese cabbage because more K+ than Na+ was absorbed and translocated from roots to shoots.  相似文献   

18.
Soybean plants, varieties “Lee”, “Jackson” and “Bragg” were grown in solution culture at various salinity levels. A NaCl concentration of 10 mM was already inhibitory to growth of “Jackson”; growth of “Lee”, however, was only reduced at a salt concentration of 50 mM or higher. The moderately salt tolerant variety “Lee” efficiently excluded Cl? from the leaves up to about 50 mM NaCl in the medium, but showed high Cl? contents in the root; exclusion of Na+ from the leaves was also apparent in this variety. On the other hand, the salt sensitive variety “Jackson” did not have the capacity for exclusion of Cl? and Na+. The physiological behaviour of the variety “Bragg” resembled that of “Jackson”. It is suggested that the exclusion of Cl? and Na+ from the leaves in the soybean variety “Lee” is regulated by the root.  相似文献   

19.
Soil salinity is a concern in the wake of climate change challenges due to rising sea levels and coastal salinity in Papua New Guinea. A greenhouse experiment was conducted in Split Plot design, with five elite sweet potato genotypes (main-plot factors) and three levels of sodium chlroide (NaCl) concentrations (sub-plot factors) replicated six times. The vine cuttings of genotype RAB 45 showed very low mortality percentage (33%) at 600 mM NaCl concentration. At salinity level of 200 mM NaCl, aerial dry biomass of the genotypes was inversely but significantly (r = –0.40; p < 0.05) related to the accumulation of sodium (Na+) in the tissues. The Na+ accumulation in the tissues was antagonistic to the potassium (K+) and calcium (Ca2+) ions. Among the sweetpotato genotypes, Na+/K+ ratio decreased in the following order: RAB 45> KAV 11 > Northern Star > DOY 2 > L 46, which was more or less corroborated with the trend in the aerial dry matter.  相似文献   

20.
Plant dry matter accumulation rate (DMAR), relative water content (RWC), electrolyte leakage percentage (ELP), chlorophyll content, osmotic adjustment ability (OAA), and osmotica accumulation in leaves of sunflower (Helianthus annuus L.) seedlings under different levels of dehydration and salinity stress induced by iso-osmotic PEG (polyethylene glycol) or sodium chloride (NaCl) were evaluated. Plants were subjected to four stress treatments for 10 days: ?0.44 MPa PEG6000, ?0.44 MPa NaCl, ?0.88 MPa PEG6000, ?0.88 MPa NaCl. Results showed that PEG and NaCl treatments decreased the plant's DMAR and RWC, and NaCl treatments had more severe inhibitory effect on the plants than PEG treatments. Leaf ELP in sunflower seedlings increased after NaCl and PEG treatments. However, leaf ELP under salt stress was higher than that under dehydration stress (PEG treatment). All stress treatments increased OAA in plant leaves. Leaf OAA was enhanced significantly as PEG concentration increases, while leaf OAA was less enhanced at higher concentration of NaCl. OAA of sunflower leaves under dehydration stress was due to an increase in potassium (K+), calcium (Ca2+), amino acid, organic acid, magnesium (Mg2+), and proline content. OAA of sunflower leaves under moderate salt stress was owing to an increase in K+, chlorine (Cl?), amino acid, organic acid, sodium (Na+), and proline content, and was mainly due to an accumulation of K+, Cl?, Na+, and proline under severe salt stress.  相似文献   

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