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1.
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   

2.
A study of the salinity effect on mineral content in rice genotypes differing in salt tolerance was conducted in a factorial Completely Randomized Design experiment. The results indicated that the genotypes developed differently by mutation conventional breeding. NS15 represented as salt-sensitive, Pokkali was included as an internationally salt-tolerant check and Iratom24 was moderately tolerant. The content of Na+, Ca2+, Mg2+ and Cl? followed an increasing pattern in roots and shoots of all the rice genotypes due to increasing salinity levels except Ca2+ and Mg2+ in the root. However, the concentration of K+ showed more or less an increasing pattern in root and a decreasing pattern in shoot. The concentration of Na+ and Ca2+ sharply increased with increasing the salinity levels in both the roots and shoots of NS15. The concentration of K+ sharply decreased in shoot and increased in the root of susceptible genotype NS15 with increasing salinity over 6 dS m?1 salinity levels, where the transformation of K+ from root to shoot was disrupted by Na+. The Cl? content sharply increased with increasing salinity in the root of NS15 as compared to shoot. The effect of different salinity levels on Na+/K+ ratio in the shoots of the selected rice genotypes sharply increased in susceptible genotype NS15 as compared to the other genotypes.  相似文献   

3.
In order to study the effects of salinity and water stress on growth and macronutrients concentration of pomegranate plant leaves, a factorial experiment was conducted based on completely randomized design with 0, 30, and 60 mM of salinity levels of sodium chloride and calcium chloride (1:1) and three irrigation intervals (2, 4, and 6 days) with 3 replications on ‘Rabab’ and ‘Shishegap’ cultivars of pomegranate. The results of the shoot and root analysis indicated that the salinity and drought affected the concentration and distribution of sodium (Na+), potassium (K+), chloride (Cl?), calcium (Ca2+), magnesium (Mg2+), and phosphorus (P+) in pomegranate leaves. Mineral concentrations of sodium (Na+), chloride (Cl-), potassium (K+), in shoots and roots were increased with increasing salinity. Drought treatments increased the concentration of Cl?, Na+, and Mg2+ in the shoot. Both cultivars showed significant differences in the concentrations of elements, however the most accumulation of Na+ and Cl? was observed in ‘Rabab,’ while the ‘Shishegap’ cultivar had the most absorption of K+. ‘Shishegap’ cultivar showed higher tolerance to salinity than ‘Rabab’ through maintaining the vegetative growth and lower chloride transport to the shoot, and improvement of potassium transport to shoot.  相似文献   

4.
We investigated the effect of exogenously applied silicon (Si) on the growth and physiological attributes of wheat grown under sodium chloride salinity stress in two independent experiments. In the first experiment, two wheat genotypes SARC-3 (salt tolerant) and Auqab 2000 (salt sensitive) were grown in nutrient solution containing 0 and 100 mM sodium chloride supplemented with 2 mM Si or not. Salinity stress substantially reduced shoot and root dry matter in both genotypes; nonetheless, reduction in shoot dry weight was (2.6-fold) lower in SARC-3 than in Auqab 2000 (5-fold). Application of Si increased shoot and root dry weight and plant water contents in both normal and saline conditions. Shoot Na+ and Na+:K+ ratio also decreased with Si application under stress conditions. In the second experiment, both genotypes were grown in normal nutrient solution with and without 2 mM Si. After 12 days, seedlings were transferred to 1-l plastic pots and 150 mM sodium chloride salinity stress was imposed for 10 days to all pots. Shoot growth, chlorophyll content and membrane permeability were improved by Si application. Improved growth of salt-stressed wheat by Si application was mainly attributed to improved plant water contents in shoots, chlorophyll content, decreased Na+ and increased K+ concentrations in shoots as well as maintained membrane permeability.  相似文献   

5.
Bermudagrass (Cynodon dactylon) is a salinity-tolerant turfgrass that has good use potential in the saline-alkali lands of warm regions. However, the systematic Na+ and K+ regulation mechanisms under salinity stress remain unclear at the whole plant level. Two bermudagrass cultivars differing in salinity tolerance were exposed to 0, 50, 100, 200, or 300 mM NaCl in a hydroponic system. Growth, absorption, transportation, and secretion of Na+ and K+, and gas exchange parameters were determined in both cultivars. K+ contents were decreased and Na+ contents and Na+/K+ ratios were increased in both bermudagrasses with increased salinity; however, lower Na+ content and Na+/K+ ratio and more stable K+ content were found in the leaves of the salinity-tolerant ‘Yangjiang’ than the salinity-sensitive ‘Nanjing’. Higher Na+ contents in root cortical cells were found than in the stele cells of ‘Yangjiang’, but the opposite was observed in ‘Nanjing’. Lower Na+ contents and higher K+ contents were found in vessels for ‘Yangjiang’ than for ‘Nanjing’. Salinity stress increased the selective transport of K+ over Na+ from roots to leaves and the Na+-selective secretion via salt glands, which were stronger in ‘Yangjiang’ than ‘Nanjing’. Net photosynthetic rate and stomatal conductance decreased in the two bermudagrasses with increased salinity; however, they were more stable in ‘Yangjiang’. The results suggested that bermudagrass could reduce Na+ accumulation and maintain K+ stability in leaves under salinity stress by restricting Na+ into vessels in roots, selectively transporting K+ over Na+ from roots to leaves, selectively secreting Na+ via leaf salt glands, and maintaining suitable stomatal conductance.  相似文献   

6.
Osmotic and specific ion effects are the most frequently mentioned mechanisms by which saline substance reduces plant growth. However, the relative importance of osmotic and specific ion effect on plant growth seems to vary depending on the salt tolerance of the plant under study. Tall wheatgrass (TW), perennial ryegrass (PR), African millet (AM) and Rhodesgrass (Rh) were grown in nutrient solution with sodium chloride (NaCl), sodium sulfate (Na2SO4), potassium chloride (KCl), and potassium sulfate (K2SO4) salinity up to electrical conductivity (EC) 27 dS m?1. Growth of all plant species decreased significantly at high level (EC 27 dS m?1) of NaCl and Na2SO4 salts. However, the growth of none of the plant species was affected significantly by KCl and K2SO4 at any level. Even leaf and shoot fresh weights were enhanced by K2SO4 in all plant species, except AM. Chlorine (Cl) was taken up in similar quantities from KCl and NaCl solutions and the content of the respective cations was similar to each other. Further sensitivity to sulfate and chloride was equal when sodium concentrations in shoots were equal, regardless of the anion composition of the media. The sodium (Na) concentration of the leaves of the plant species increased with increased NaCl and Na2SO4 levels in the nutrient solutions. The leaf Na concentration of TW was lower than that of the other plant species. However, the root Na concentration of TW was higher than that of the other plant species. Increased NaCl and Na2SO4 concentrations had a marked effect on leaf water potential of all plant species, and the TW showed higher leaf water potential at all levels of salts. Tall wheatgrass adjusted osmotically by accumulating electrolytes from the nutrient solution and by accumulation of glycinebetaine. Sodium was generally found more injurious than Chloride in all the four forage species. Salt tolerance could be ascribed as greater exclusion of Na ion.  相似文献   

7.
Abstract

Effects of increasing salt concentrations 0, 180, 360 mol im3 sodium chloride (NaCl), on growth, succulence, mineral composition, and glycinebetaine content in Haloxylon recurvum was investigated. Fresh and dry weight of plants increased with an increase in salinity. Succulence of shoots increased at low salinity and decreased at high salinity. Root and shoot Ca+, Mg+, and K+content decreased with increasing salinity while both Na+ and Cl‐ content increased, reaching 4,900 and 5,300 mmol kg‐1 dry weight, respectively. Glycinebetaine (mol m‐3 tissue water) significantly increased in shoots at 360 mol m‐3 NaCl, but did not differ significantly in roots treated with from 0 to 360 mol m‐3 NaCl. Haloxylon recurvum is a highly salt tolerant stem succulent plant which accumulate a high quantity of salt, which makes it a good candidate to use for phytoremediation in highly saline areas of the sub‐tropics.  相似文献   

8.
Abstract

Silicon (Si) is the second most abundant element in soil and effectively counteracts the effects of various abiotic stresses, such as drought, heavy metal toxicity and salinity, on plants. In the present study the ameliorating effects of Si nutrition supplied as 2?mmol?L?1 sodium silicate were investigated on hydroponically grown canola (Brassica napus L.) plants under salinity stress (i.e. 150?mmol?L?1 sodium chloride). Salinity decreased plant growth parameters such as tissue fresh and dry weights. These decreases were accompanied by increased lignin contents, Na+ ion accumulation, increased lipid peroxidation and decreased chlorophyll contents in plants. Silicon nutrition, however, enhanced plant growth parameters and led to the prevention of lignin and the Na+ accumulation in shoots, reduced levels of lipid peroxidation in the roots and higher levels of chlorophyll. As a result of salinity, catalase activity in the whole plant and both soluble and cell wall peroxidase activities in the shoots decreased. Silicon nutrition, however, increased the reactive oxygen species scavenging capacity of salt-stressed plants through increased catalase and cell wall peroxidase activities. Thus, silicon nutrition ameliorated the deleterious effects of salinity on the growth of canola plants through lower tissue Na+ contents, maintaining the membrane integrity of root cells as evidenced by reduced lipid peroxidation, increased reactive oxygen species scavenging capacity and reduced lignification.  相似文献   

9.
Strawberry is listed as the most salt sensitive fruit crop in comprehensive salt tolerance data bases. Recently, concerns have arisen regarding declining quality of irrigation waters available to coastal strawberry growers in southern and central California. Over time, the waters have become more saline, with increasing sodium (Na+) and chloride (Cl?). Due to the apparent extreme Cl? sensitivity of strawberry, the rising Cl? levels in the irrigation waters are of particular importance. In order to establish the specific ion causing yield reduction in strawberry, cultivars ‘Ventana’ and ‘Camarosa’ were grown in twenty-four outdoor sand tanks at the ARS-USDA U. S. Salinity Laboratory in Riverside, CA and irrigated with waters containing a complete nutrient solution plus Cl? salts of calcium (Ca2+), magnesium (Mg2+), Na+, and potassium (K+). Six salinity treatments were imposed with electric conductivities (EC) = 0.835, 1.05, 1.28, 1.48, 1.71, and 2.24 dS m?1, and were replicated four times. Fresh and dry weights of ‘Camarosa’ shoots and roots were significantly higher than those of ‘Ventana’ at all salinity levels. Marketable yield of ‘Camarosa’ fruit decreased from 770 to 360 g/plant as salinity increased and was lower at all salinity levels than the yield from the less vigorous ‘Ventana’ plants. ‘Ventana’ berry yield decreased from 925 to 705 g/plant as salinity increased from 0.835 to 2.24 dS m?1. Relative yield of ‘Camarosa’ decreased 43% for each unit increase in salinity once irrigation water salinity exceeded 0.80 dS m?1. Relative ‘Ventana’ yield was unaffected by irrigation water salinity up to 1.71 dS m?1, and thereafter, for each additional unit increase in salinity, yield was reduced 61%. Both cultivars appeared to possess an exclusion mechanism whereby Na+ was sequestered in the roots, and Na+ transport to blade, petiole and fruit tissues was limited. Chloride content of the plant organs increased as salinity increased to 2.24 dS m?1 and substrate Cl increased from 0.1 to13 mmolcL?1. Chloride was highest in the roots, followed by the leaves, petioles and fruit. Based on plant ion relations and relative fruit yield, we determined that, over the range of salinity levels studied, specific ion toxicity exists with respect to Cl?, rather than to Na+ ions, and, further, that the salt tolerance threshold is lower for ‘Camarosa’ than for ‘Ventana’.  相似文献   

10.
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   

11.
The effects of nitrogen (N) forms (ammonium- or nitrate-N) on plant growth under salinity stress [150 mmol sodium chloride (NaCl)] were studied in hydroponically cultured cotton. Net fluxes of sodium (Na+), ammonium (NH4+), and nitrate (NO3?) were also determined using the Non-Invasive Micro-Test Technology. Plant growth was impaired under salinity stress, but nitrate-fed plants were less sensitive to salinity than ammonium-fed plants due mainly to superior root growth by the nitrate-fed plants. The root length, root surface area, root volume, and root viability of seedlings treated with NO3-N were greater than those treated with NH4-N with or without salinity stress. Under salinity stress, the Na+ content of seedlings treated with NO3-N was lower than that in seedlings treated with NH4-N owing to higher root Na+ efflux. A lower net NO3? efflux was observed in roots of nitrate-fed plants relative to the net NH4+ efflux from roots of ammonium-fed plants. This resulted in much more nitrogen accumulation in different tissues, especially in leaves, thereby enhancing photosynthesis in nitrate-fed plants under salinity stress. Nitrate-N is superior to ammonium-N based on nitrogen uptake and cotton growth under salinity stress.  相似文献   

12.
The effect of varying hydrogel (0, 0.5, and 1.0% w/w) supply on some agro-physiological properties, such as dry matter, nutrient contents, chlorophyll contents, proline content, and ionic balance of bean plants in different salt sources and stress due to doses were investigated. Plants were treated with eight salt sources [sodium chloride (NaCl), sodium sulfate (Na2SO4), calcium chloride (CaCl2), calcium sulfate (CaSO4), potassium chloride (KCl), potassium sulfate (K2SO4), magnesium chloride (MgCl2), magnesium sulfate (MgSO4)] and four concentrations (0, 30, 60, and 120 mM doses) for 60 days in a growth media. Salt type, doses, and hydrogel (HG) affected the soil electrical conductivity. Soil salinity affected the parameters considered, and changed the nutrient balance of plants. High salt concentration caused substantial reduction in plant growth. Different salt concentrations negatively affected plant dry weight. The highest decrease of plant root dry weight was obtained with NaCl application followed by Na2SO4, CaCl2, CaSO4, MgCl2, MgSO4, KCl, and K2SO4, and similarly NaCl, Na2SO4, CaCl2, CaSO4, KCl, K2SO4, MgCl2, and MgSO4 in root dry weight. Total chlorophyll and nitrate contents of plants decreased with increasing salt doses, and the lowest value was obtained for NaCl application. Proline contents of plants were increased with increasing salt doses, and the highest value was obtained with the NaCl application. The effects of salt concentrations in nitrogen (N), potassium (K), and phosphorus (P) content of plants were significant. The presence of salt in the growth medium induced an important decrease the macro nutrient of the root and shoot part of plant such as N, P, K, calcium (Ca), and magnesium (Mg) content, but the N and P content of root and shoot part of the plant were increased with increasing of the HG application doses. The highest N and P increases were obtained with the 1.0 HG application for all salt types for both the root and shoots of plants. The HG added to saline soil significantly improved the variables affected by high salinity and also increased plant N and P, reduced soil electricity conductivity, nitrate, proline, and electrolyte leakage of plants, enhanced plant root and shoot dry weight by allowing nutrients and water to release to the plant as needed. The results suggested that HG has great potential for use in alleviating salinity stress on plant growth and growth parameters in saline soils of arid and semi-arid areas. This HG appears to be highly effective for use as a soil conditioner in vegetable growing, to improve crop tolerance and growth in saline conditions. It is intended to confirm the results of these studies by field trials.  相似文献   

13.
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14.
This study assessed the relationships between external K+ supply and K+ : Na+ ratios associated with Na+ toxicity in Jatropha curcas. Plants were exposed to increasing external K+ concentrations (6.25, 12.5, 25, 37.5, and 50 mM), combined with 50 mM NaCl in a nutrient solution. Photosynthesis progressively increased as the external K+ : Na+ ratios increased up to 0.75. The increase of photosynthesis and plant dry matter correlated positively with K+ : Na+ in xylem and leaves. The transport rates of K+ and Na+ from roots to xylem and leaves were inversely correlated. These ions presented an antagonistic pattern of accumulation in all organs. Maximum rates of photosynthesis and plant growth occurred with leaf K+ : Na+ ratios that ranged from 1.0 to 2.0, indicating that this parameter in leaves might be a good indicator for a favorable K+ homeostasis under salinity conditions. The higher K+ affinity and selectivity compared with Na+ in all organs associated with higher xylem flux and transport to shoots are essential for maintaining adequate K+ : Na+ ratios at the whole‐plant level. These characteristics, combined with adequate K+ concentrations, allow J. curcas to sustain high rates of photosynthesis and growth even under toxic NaCl levels.  相似文献   

15.
Infection with Neotyphodium spp. endophytes increases resistance to drought stress and soil mineral imbalances in tall fescue (Festuca arundinacea Schreb. = Lolium arundinaceum (Schreb.) S. J. Darbysh.) and meadow fescue (Festuca pratensis Huds. = Lolium pratense (Huds.) Darbysh.). We hypothesized that resistance of these grasses to salinity stress may also be attributed to endophyte infection. Two tall fescue genotypes, Fa75 and Fa83, and one meadow fescue genotype, Fp60, infected (E+) with their endophytic fungi, Neotyphodium coenophialum (Glenn, Bacon and Hanlin) and N. uncinatum (Glenn, Bacon and Hanlin), respectively, and their noninfected counterparts (E–) were cultured in nutrient solution at three salinity levels of 0, 85, and 170 mM NaCl. Except for genotype Fa75, E+ plants exhibited higher leaf survival rates than E– clones at a high salinity level (170 mM). Root dry matter was higher in E+ than in E– plants, but shoot dry matter was not affected by endophyte infection. This resulted in a lower shoot‐to‐root ratio in E+ plants (1.63) compared with E– plants (2.40). Sodium (Na+) and chloride (Cl–) concentrations were greater in roots of E– than in E+ clones. In shoots, Na+ and Cl– concentrations were not affected by the endophyte. In contrast, E+ plants accumulated more potassium (K+), which resulted in a greater K+ : Na+ ratio in shoots of E+ than in those of E– plants. Our results show that endophyte infection reduced Na+ and Cl– concentrations in tall fescue and meadow fescue roots but increased K+ concentrations in the shoots. Based on these results, we conclude that endophyte‐infected grasses may thrive better in salinity‐stress environments.  相似文献   

16.
An experiment with factorial arrangement of treatments on a randomized complete block (RCB) design basis with three replications was conducted in a greenhouse during Spring 2010 to investigate changes in sodium ion (Na+), potassium ion (K+), Na+/K+ and to determine proline, protein content, and superoxide dismutase (SOD) of four wheat and four barley cultivars. Three salt levels {1, control (no salt), 7, and 13 dS m?1 [2.5 and 5 g salt [sodium chloride (NaCl) and sodium sulfate (Na2SO4) in 1:1 ratio] per kg of soil, respectively]} were used in this investigation. Salt stress treatments were applied 4 weeks after planting (at 2 leaf stage). Leaf samples were taken four weeks after imposition of salt treatment. The results showed that salinity caused an increased in proline and protein content, and SOD in all wheat and barley cultivars. The highest proline and protein content of barley and wheat cultivars at all salinity levels were observed in ‘Nimrooz’ and ‘Bam’ cultivars, respectively. At all salinity levels, wheat and barley cultivars ‘Kavir’ and ‘Nimrooz’, respectively, had the lowest Na+ content. Barley cultivar ‘Kavir’ and wheat cultivar ‘Bam’ had higher K+ and K+:Na+ ratios. This might be related to salt tolerance in these two cultivars. Wheat and barley cultivars showed differences with regard to proline, protein, and SOD content, Na+, K+, and K+:Na+ ratio, indicating existence of genetic diversity among the cultivars. These findings indicated that higher K+, K+:Na+ ratio, proline, protein, and SOD content could be the key factors, which offer advantage to barley over wheat for superior performance under saline conditions.  相似文献   

17.
《Journal of plant nutrition》2013,36(8):1365-1374
ABSTRACT

Salt tolerance of Arthrocnemum macrostachyum (Moric.) C. Koch (Chenopodiaceae), a stem-succulent halophyte most commonly found in the intertidal regions of the provinces of Sind and Balochistan, Pakistan, was investigated. Plants were grown for 125 d at six sodium chloride (NaCl) concentrations from 0 to 1000 mM to determine the effects of salinity on ion accumulation, plant water status, and biomass. Shoot biomass was greatest at 200 to 400 mM NaCl, but it was inhibited at salinities of 600 mM NaCl or higher. Tissue water content (g g?1dry mass) of shoots under 200 to 600 mM NaCl treatments was higher than under the control nutrient solution, equal to the control at 800 mM NaCl, but significantly lower at 1000 mM NaCl than under all other treatments, indicating an increase in shoot succulence at salinity levels up to that of seawater. Ash content increased with added salt, but was about 60% of plant dry mass under all salinity treatments. The Na+ and Cl? concentrations of shoots were significantly higher under 1000 mM NaCl than under the control treatment. These results indicate that A. macrostachyum is salt tolerant and capable of accumulating large quantities of Na+ and Cl? when treated with from 200 to 1000mM NaCl.  相似文献   

18.
塔里木河下游绿洲灌区土壤盐渍化特征及季节性变化规律   总被引：1，自引：1，他引：1  
[目的]研究典型绿洲灌区土壤盐渍化特征和季节性变化规律,为农业生产调控提供理论依据。[方法]运用GPS定位技术在塔里木河下游三十一团灌区不同季节进行调查与采样,并结合室内样品测定结果,对该区土壤盐分含量和各盐分离子含量进行经典统计分析和地统计学分析。[结果]研究区土壤的pH值范围在8.09～8.24之间,不同季节之间的差异不大,土壤呈碱性。土壤盐分含量受季节影响明显,在不同深度均表现为:秋季冬季春季夏季。不同季节下各深度的土壤中主要离子均相同,土壤盐分组成中阴离子主要为SO■和Cl~-,阳离子主要为K~+和Na~+,土壤盐分类型春季和秋季以硫酸盐型为主,冬季以氯化物—硫酸盐型为主。秋季与冬季的土壤盐分含量随着土层深度的增加逐渐减小,总体呈表聚型,春季与夏季的土壤盐分含量随着土层深度的增加呈先减小后增大的趋势,总体呈底聚型。春季根域层(0—60 cm)土壤的盐分在东南部的含量较高,西北部的含量较低,而深层(60—100 cm)土壤盐分在东南部的含量较底,西北部的含量较高,夏季土壤盐分整体较底,且水平分布较为一致。秋季、冬季土壤盐分的高值区都出现在研究区的西南方向,靠近塔里木河,原始保留地和荒地较多的区域。[结论]三十一团灌区土壤盐分的周年变化总体表现为秋季、冬季积盐,春季、夏季脱盐,土壤盐分的水平分布主要受土地利用类型、地形因素以及与水源位置距离的影响。  相似文献   

19.
民勤绿洲盐生草生境土壤盐分特征及离子组成   总被引：2，自引：0，他引：2  
对民勤绿洲盐生草周围不同距离范围内的总体盐分状况、盐分离子组成及离子之间的相关性进行了研究。结果表明,盐生草具有一定的聚盐作用,在其周围形成了一定的"盐岛"效应。在距盐生草0-60 cm范围内,土壤剖面中的土壤盐渍化程度随土层的加深而加重,土壤阴离子主要有Cl-和SO42-,阳离子主要有Na+和Ca2+,土壤盐分主要是氯化钠、氯化钙、硫酸钠和硫酸钙,其次是氯化镁和硫酸镁。其中在盐生草周围0-40 cm范围内,垂直剖面0-20 cm土层土壤全盐含量为0.98~1.52 g/kg,属于非盐渍化土壤,20-40 cm土层土壤全盐含量达到了2.25~2.30 g/kg,属于轻度盐渍化土壤,40-60 cm土层土壤全盐含量达到了3.10~3.16 g/kg,属中度盐渍化;在距盐生草60 cm处,垂直剖面0-40 cm土层土壤全盐含量为0.83~1.86 g/kg,属非盐渍化,40-60 cm土层土壤全盐含量达到了2.43 g/kg,属轻度盐渍化。除HCO3-外,土壤盐分含量与各盐分离子之间均呈极显著正相关。  相似文献   

20.
Soil or foliar application of nitrogen (N) can increase plant growth and salinity tolerance in cotton, but a combination of both methods is seldom studied under salinity stress. A pot experiment was conducted to study the effects of soil application (S), foliar application (F), and a combination of both (S+F) with labeled nitrogen (15N) on cotton growth, N uptake and translocation under salinity stress (ECe = 12.5 dS m?1). Plant biomass, leaf area, leaf chlorophyll (Chl) content, leaf net photosynthetic (Pn) rate, levels of 15N and [Na+] and K+/ Na+ ratio in plant tissues were determined at 3, 7, 14 and 28 days after N application (DAN). Results showed that soil or foliar nitrogen fertilization improved plant biomass, leaf area per plant and leaf photosynthesis, and a combination of soil- plus foliar-applied N was superior to either S or F alone under salinity stress. Although foliar application favored a rapid accumulation of leaf N and soil application a rapid accumulation of root N, S+F enhanced N accumulation in both leaf and root under salinity stress. The combined N application also maintained significantly greater [K+] and K+/Na+ than either soil or foliar application alone. Therefore, the improved plant growth and salinity tolerance under S+F relative to soil or foliar N application alone was attributed to the increased total uptake of N, balanced N concentrations in different tissues through enhanced uptake and accumulation in both leaves and roots, and higher ratio of K+/Na+.  相似文献   

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