盐胁迫下柚实生苗生长、矿质营养及离子吸收特性研究

以坪山柚为材料,对盐胁迫下实生苗生长、矿质营养及离子吸收特性进行了研究。结果表明,沙培30d,80～200mmol/L盐胁迫,随盐浓度提高,坪山柚实生苗株高、叶面积、地上部干重和根部干重明显降低。溶液培养8d,坪山柚实生苗地上部及根Na+、Cl-含量随盐浓度的增加而增加,根及地上部K+、Ca2+、Mg2+以及P和Mn含量下降,Fe、Zn、Cu含量的变化因器官而异。其中,地上部Fe含量对盐胁迫敏感,可作为柚耐盐性鉴定指标。40mmol/L盐胁迫,坪山柚地上部K+/Na+、Ca2+/Na+、Mg2+/Na+值均显著下降,且Mg2+/Na+值+/Na+值>1;浓度≥160mmol/L盐胁迫,K+/Na+值+吸收、运转效率比Cl-高。     

稀释海水灌溉的芦荟中矿质营养与有效成分分布情况研究

With increasing demand for irrigation water, agricultural scientists and planners pay more attention to the utilization of diluted seawater as an alternative source for irrigation of crops. A greenhouse pot experiment was conducted to study how seawater stress（SS） affects growth, water content, cationic accumulation, and active ingredients in leaves of Aloe vera after 30 d of growth in nutrient media with 0%（control）, 22%（22% SS）, and 42%（42% SS） seawater stress. Results indicated the SS did not change dry biomass of leaves and stems, but gradually decreased biomass allocation to roots with increasing seawater stress. Na^＋ and Cl^- in A. vera plant did not increase obviously with a big increase in seawater percentage due to low transpiration of Aloe vera. 42% SS decreased N concentration in most plant organs, but did not change or increased P concentration. Seawater stress tended to decrease concentrations of K^＋ and Ca^2＋ in A. vera. However, seawater salinity tended to increase the concentrations of aloin concentration in top（young） and middle leaves, and there was no significant effect of both stresses on aloin concentration in base（old） leaves. The 42% SS treatment decreased polysaccharide concentrations only in the base leaves, but not in top and middle leaves. In summary, supplying suitably diluted seawater for 30 d could increase the qualities and value of A. vera, without substantial effects on shoot dry biomass production.     

Interactive Effect of Soil Salinity and Water Stress on Growth and Chemical Compositions of Pistachio Nut Tree

ABSTRACT

The effects of three sodium chloride (NaCl) levels (0, 1200, and 2400 mg kg^{? 1} soil) and three irrigation intervals (3, 7, and 14 d) on the growth and chemical composition of two Pistacia vera rootstocks (‘Sarakhs’ and ‘Qazvini’) were investigated under greenhouse conditions. Eight-week-old pistachio seedlings were gradually exposed to salt stress which afterward, water stress was initiated. At any irrigation interval, plant height and shoot and root dry weights of both rootstocks were reduced with increasing salinity. However, increasing irrigation intervals alleviated the adverse effects of soil salinity. A negative relationship observed between relative shoot growth and electrical conductivity of soil saturation extract (EC_e) confirmed the above findings. Under 3-d irrigation interval, the EC_e required to cause a 50% growth reduction was lower than those under 7- and/or 14-d irrigation intervals. Shoot and root chemical analyses indicated that the salinity as well as irrigation regime affected the concentration and distribution of sodium (Na⁺), potassium (K⁺), and chloride (Cl^?) in pistachio. The concentration of Na⁺, K⁺ and C1^? ions increased with a rise in NaCl level, and was generally declined with increasing irrigation interval. Based on plant height, shoot and root dry weights and the concentrations of Na⁺, K⁺, and C1^? in the plant tissues, at lowest irrigation intervals ‘Sarakhs’ shows a higher sensitivity to soil salinity than ‘Qazvini’, but with increasing irrigation interval, ‘Sarakhs’ and ‘Qazvini’ can be classified as resistant and sensitive to salinity, respectively.     

Effect of grafting on the growth and ion concentrations of cucumber seedlings under NaCl stress

Abstract

To assess whether grafting raised the salt tolerance of cucumber seedlings by limiting transport of Na⁺ to the leaf and to test whether the salt tolerance of grafted plants was affected by the shoot genotype, two cucumber cultivars (“Jinchun No. 2”, a relatively salt-sensitive cultivar, and “Zaoduojia”, a relative salt-tolerant cultivar) were grafted onto rootstock pumpkin (Cucurbita moschata Duch. cv. “Chaojiquanwang”, a salt-tolerant cultivar). Ungrafted plants were used as controls. The effects of grafting on plant growth and ion concentrations were investigated under NaCl stress. Reductions in the shoot and root dry weights, leaf area and stem diameter of grafted plants were lower and concentrations of K⁺ and Cl^? in the leaves were higher than those of ungrafted plants under the same NaCl stress. The Na⁺ concentration and Na⁺/K⁺ ratio in scion leaves and in the stems of grafted plants were lower, whereas those in rootstock stems and roots were higher than in ungrafted plants under the same NaCl stress. Shoot and root dry weight, leaf area and stem diameter were negatively correlated with leaf Na⁺ concentrations and Na⁺/K⁺ ratio, but were positively correlated with leaf K⁺ concentrations. The Na⁺ concentrations and Na⁺/K⁺ ratio were lower, whereas the K⁺ concentrations in the leaves of grafted “Zaoduojia” plants were higher than those in grafted “Jinchun No. 2” plants under the same NaCl stress. The reductions in leaf area and stem diameter of grafted “Jinchun No. 2” plants were more severe than those of grafted “Zaoduojia” plants. These results indicate that: (1) the higher salt tolerance of grafted cucumber seedlings is associated with lower Na⁺ concentrations and Na⁺/K⁺ ratio and higher K⁺ concentrations in the leaves, (2) grafting improved the salt tolerance of cucumber seedlings by limiting the transport of Na⁺ to the leaves, (3) the salt tolerance of grafted cucumber seedlings is related to the shoot genotype.     

Effect of nitrogen nutrition on salt tolerance of Pisum sativum during vegetative growth

The influence of different nitrogen (N) forms on salt tolerance of Pisum sativum L. was investigated. Plants of the pea cultivar “Resal” were subjected to 0 (control) or 90 mM NaCl and one of the following nitrogen forms: 5 mM mineral N supplied as either NO , NH , or NH₄NO₃ or N supplied by biological N₂ fixation (inoculated with Rhizobium leguminosarum bv. viciae). Root and shoot biomass were determined 15, 30, 45, and 60 d after emergence, and Na⁺, K⁺, and Cl^– concentrations were determined by capillary electrophoresis. Nitrogen sources induced significant differences in plant growth and in ion accumulation and distribution and in differentially affected salt tolerance. In the absence of salt, the largest biomass accumulation was obtained with NH₄NO₃. In the presence of NaCl, NO ‐fed plants experienced less salt toxicity than plants supplied with other N sources, as indicated by lower Na⁺ and Cl^– and higher K⁺ concentrations in the shoot. The results also suggest that it is possible to establish an effective symbiosis under saline conditions, provided that a salt‐tolerant Rhizobium isolate with good N₂‐fixing ability is used. The use of the appropriate N‐fertilizer source can enhance the growth of Pisum sativum. Hence, NH₄NO₃ may be preferably used under non‐saline and NO under moderately saline conditions.     

Nitrate Reduction and Nutrient Accumulation in Wheat Grown in Soil Salinized with Four Different Salts

ABSTRACT

The effect of salinization of soil with Na₂SO₄, CaCl₂, MgCl₂, and NaCl (70:35:10:23) on the biochemical characteristics of three wheat (Triticum aestivum L.) cultivars (‘LU-26S,’ ‘Sarsabaz’ and ‘Pasban-90’) was investigated under natural environmental conditions. Twenty-day-old seedlings of all three cultivars were subjected to three salinity treatments: 1.3 (control), 5.0, and 10 dSm^?1 for the entire life period of plants. After 120 d of seed sowing, plant biomass production decreased by 49% and 65%, respectively, in response to 5 and 10 dSm^?1 salinity levels. Addition of salts to growth medium also had a significant adverse effect on plant height. Increasing salinity treatments caused a great reduction in nitrate reductase activity (NRA) of the leaf. The inhibitory effect of salinity on nitrate reduction rate was more pronounced at the reproductive stage than at the vegetative stage of plant growth. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ showed less reduction in NRA due to salinity compared with ‘Pasban-90.’ Ascending salinity levels significantly reduced potassium (K⁺) and calcium (Ca²⁺) accumulation in shoots, while the concentration of sodium (Na⁺) was increased. Salts of growth medium increased the shoot nitrogen (N) concentration, whereas phosphorous (P) concentration of shoots was significantly reduced due to salinity. Wheat cultivars ‘LU-26S’ and ‘Sarsabaz’ proved to be the salt-tolerant ones, producing greater biomass, showing less reduction in NRA, maintaining low sodium (Na⁺), and accumulating more K⁺ and Ca²⁺ in response to salinity. These two cultivars also showed less reduction in shoot K⁺/Na⁺ and Ca⁺/Na⁺ ratios than in ‘Pasban-90,’ particularly at the 10 dSm^?1 salinity level.     

硝态氮对盐胁迫下囊果碱蓬幼苗根系生长和耐盐性的影响

在溶液培养条件下,设计了4个盐分（1,150,300或450 mmol/L NaCl）和3个氮素（0.05,5或10 mmol/L NO3--N）水平,研究了盐、氮及其互作对囊果碱蓬（Suaeda physophora Pall.）幼苗的离子吸收、氮营养状况、根系形态特征及耐盐性的影响。结果表明,与低盐或低氮相比,增加盐分或氮水平显著增加了囊果碱蓬根部的干重、根系的侧根长、表面积、总吸收面积和活跃吸收面积;且这些根系的形态指标与地上部的离子及氮的累积存在显著的正相关。高盐胁迫下增加氮营养,显著增加了地上部Na+、NO3-、有机氮的含量和硝酸还原酶的活性;降低了Cl-和K+的含量。高盐胁迫下,硝态氮的增加促进了囊果碱蓬幼苗根系的生长,增加了地上部有机氮、NO3-和Na+的累积,改善了植株的营养状况和渗透调节,从而提高了囊果碱蓬的耐盐能力。     

Growth,Mineral Composition,and Biochemical Changes of Broad Bean as Affected by Sodium Chloride and Zinc Levels and Sources

Plants grown in salt‐affected soils may suffer from limited available water, ion toxicity, and essential plant nutrient deficiency, leading to reduced growth. The present experiment was initiated to evaluate how salinity and soil zinc (Zn) fertilization would affects growth and chemical and biochemical composition of broad bean grown in a calcareous soil low in available Zn. The broad bean was subjected to five sodium chloride (NaCl) levels (0, 10, 20, 30, and 40 m mol kg^?1 soil) and three Zn rates [0, 5, and 10 mg kg^?1 as Zn sulfate (ZnSO₄) or Zn ethylenediaminetetraaceticacid (EDTA)] under greenhouse conditions. The experiment was arranged in a factorial manner in a completely randomized design with three replications. Sodium chloride significantly decreased shoot dry weight, leaf area, and chlorophyll concentration, whereas Zn treatment strongly increased these plant growth parameters. The suppressing effect of soil salinity on the shoot dry weight and leaf area were alleviated by soil Zn fertilization, but the stimulating effect became less pronounced at higher NaCl levels. Moreover, rice seedlings treated with ZnSO₄ produced more shoot dry weight and had greater leaf area and chlorophyll concentration than those treated with Zn EDTA. In the present study, plant chloride and sodium accumulations were significantly increased and those of potassium (K), calcium (Ca), and magnesium (Mg) strongly decreased as NaCl concentrations in the soil were increased. Moreover, changes in rice shoot Cl^?, Na⁺, and K⁺ concentrations were primarily affected by the changes in NaCl rate and to a lesser degree were related to Zn levels. The concentrations of Cl^? and Na⁺ associated with 50% shoot growth suppression were greater with Zn‐treated plants than untreated ones, suggesting that Zn fertilization might increase the plant tolerance to high Cl^? and Na⁺ accumulations in rice shoot. Zinc application markedly increased Zn concentration of broad bean shoots, whereas plants grown on NaCl‐treated soil contained significantly less Zn than those grown on NaCl‐untreated soil. Our study showed a consistent increase in praline content and a significant decrease in reducing sugar concentration with increasing salinity and Zn rates. However, Zn‐treated broad bean contained less proline and reducing sugars than Zn‐untreated plants, and the depressing impact of applied Zn as Zn EDTA on reducing sugar concentration was greater than that of ZnSO₄. In conclusion, it appears that when broad bean is to be grown in salt‐affected soils, it is highly advisable to supply plants with adequate available Zn.     

Interactive Effects of Inoculated Cucumber (Cucumis sativus L.) Seedlings and Saline Soil

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.     

Is salt stress of faba bean (Vicia faba) caused by Na+ or Cl– toxicity?

The effect of sodium chloride (NaCl), sodium sulfate (Na₂SO₄), and potassium chloride (KCl) on growth and ion concentrations of faba bean (Vicia faba L. cv. Troy) was studied. After 14 or 15 d of isoosmotic treatment with 100 mM NaCl or 75 mM Na₂SO₄, respectively, plants developed toxicity symptoms. These symptoms were characterized by local and nonchlorotic wilting spots, which later turned to black, necrotic spots. In contrast to NaCl or Na₂SO₄ treatment, plants treated with 100 mM KCl did not show these symptoms. The symptoms occurred on those leaves that accumulated highest concentrations of Na⁺ and showed highest Na⁺ : K⁺ ratios. Our results indicate that Na⁺ toxicity inducing K⁺ deficiency is responsible for the spot necrosis of faba bean. Additionally, chlorotic symptoms occurred. The concentrations of Na⁺ and Cl^– were determined in chlorotic leaves and in isolated chloroplasts. The reduction of chlorophyll in leaves after NaCl exposure may be explained in terms of high Cl^– concentrations in the chloroplasts and appears to depend on high Na⁺ concentrations. Chlorotic toxicity symptoms can be avoided by additional Mg²⁺ application.     

Effect of salinity and soil temperature on the growth and physiology of drip-irrigated rice seedlings

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.     

The regulation of accumulation and secretion of several major inorganic cations by Chinese Iris under NaCl stress

Chinese Iris (Iris lactea Pall. var. chinensis (Fisch.) Koidz.) is a monocotyledonous halophyte, which is considered an important salt-tolerant species. In this study, the plant growth, ion absorption and transportation and leaf secretion characteristics of Iris under sodium chloride (NaCl) stress were investigated using nutrient solutions with four NaCl concentrations ranging from 0 to 300 mmol L^?1. The main results indicated that Na⁺ secretion accounted for 5.7–11.5% of the ion distribution pattern of 90% of the ions accumulated in vivo by Iris. The ion transportation ratio was potassium > magnesium > calcium > sodium, (K⁺ > Mg²⁺ > Ca²⁺ > Na⁺), K⁺/Na⁺, Ca²⁺/Na⁺, Mg²⁺/Na⁺ in the shoot were greater than those in the root. K–Na and Ca–Na selectivity ratios showed an increasing trend overall. The contribution of salt secretion to the salt tolerance of Iris was tiny, which will be discussed in further research, achieving ion balance in vivo through selective absorption and transportation under salt stress is undoubtedly a primary salt-tolerance adaptation mechanism of Iris.     

Arbuscular mycorrhizal fungus and rhizobacteria affect the physiology and performance of Sulla coronaria plants subjected to salt stress by mitigation of ionic imbalance

Salt stress has become a major menace to plant growth and productivity. The main goal of this study was to investigate the effect of inoculation with the arbuscular mycorrhizal fungi (AMF; Rhizophagus intraradices) in combination or not with plant growth‐promoting rhizobacteria (PGPR; Pseudomonas sp. (Ps) and Bacillus subtilis) on the establishment and growth of Sulla coronaria plants under saline conditions. Pot experiments were conducted in a greenhouse and S. coronaria seedlings were stressed with NaCl (100 mM) for 4 weeks. Plant biomass, mineral nutrition of shoots and activities of rhizosphere soil enzymes were assessed. Salt stress significantly reduced plant growth while increasing sodium accumulation and electrolyte leakage from leaves. However, inoculation with AMF, whether alone or combined with the PGPR Pseudomonas sp. alleviated the salt‐induced reduction of dry weight. Inoculation with only AMF increased shoot nutrient concentrations resulting in higher K⁺: Na⁺, Ca²⁺: Na⁺, and Ca²⁺: Mg²⁺ ratios compared to the non‐inoculated plants under saline conditions. The co‐inoculation with AMF and Pseudomonas sp. under saline conditions lowered shoot sodium accumulation, electrolyte leakage and malondialdehyde (MDA) levels compared to non‐inoculated plants and plants inoculated only with AMF. The findings strongly suggest that inoculation with AMF alone or co‐inoculation with AMF and Pseudomonas sp. can alleviate salt stress of plants likely through mitigation of NaCl‐induced ionic imbalance, thereby improving the nutrient profile.     

Individual and additive effects of Na+ and Cl− ions on rice under salinity stress

This study was attempted to assess the extent of toxicity contributed by Na⁺ and/or Cl^? ions individually, besides their possible additive effects under NaCl using physiological and biochemical parameters. Despite the fact that most annual plants accumulate both Na⁺ and Cl^? under saline conditions and each ion deserves equal considerations, most research has been focused on Na⁺ toxicity. Consequently, Cl^? toxicity mechanisms including its accumulation/exclusion in plants are poorly understood. To address these issues, effects of equimolar (100 mM) concentrations of Na⁺, Cl^? and NaCl (EC ≈ 10 dS m^?1) were studied on 15-day-old seedlings of two rice cultivars, Panvel-3 (tolerant) and Sahyadri-3 (sensitive), using in vitro cultures. All three treatments induced substantial reductions in germination rate and plant growth with greater impacts under NaCl than Na⁺ and Cl^? separately. Apparently, salt tolerance of Panvel-3 was due to its ability to exclude Na⁺ and Cl^? from its shoots and maintaining low (<1.0) Na⁺/K⁺ ratios. Panvel-3 exhibited better vigour and membrane stability indices coupled with lower reactive oxygen species and lipid peroxidation levels, besides stimulated synthesis of proline, glycine betaine and ascorbic acid. Overall, the magnitude of toxicity was observed in NaCl > Na⁺ > Cl^? manner. Though Cl^? was relatively less toxic than its countercation, its effect cannot be totally diminished.     

Growth,ion accumulation,and lipid composition of two olive genotypes under salinity 1

Olive (Olea europaea L cv. Leccino and cv. Frantoio) plants grown in aeroponic cultivation system were supplied with Hoagland solutions containing 0 and 150 mM NaCl for 4 weeks. Sodium (Na⁺), chloride (Cl^‐), and potassium (K⁺) concentration was measued on 15‐day‐old leaves and K⁺/Na⁺ selectivity ratio was calculated. Plant water relations were estimated on the same leaves by measuring leaf bulk water and osmotic potentials, and by calculating leaf turgor pressure. Root and leaf tissues were also analysed for lipid composition, estimating free sterol (FS), glycolipid (GL) and phospholipd (PL) content. The salt‐sensitive Leccino accumulated more Na⁺ and Cl^‐ in the leaves and showed a lower K⁺/Na⁺ selectivity ratio than the salt‐tolerant Frantoio. The FS/PL ratio and the content of GL (namely mono‐galactosyldiglyceride, MGDG) in the roots were related to the salt accumulation in the shoot. Salinity‐induced changes on root lipids were more important in Frantoio than in Leccino, indicating the specific role of the roots in salt exclusion mechanisms. Conversely the effect of salinity on leaf lipid composition was more important in the leaves of the salt‐sensitive Leccino.     

Simulating NaCl accumulation in a closed hydroponic crop of zucchini: Impact on macronutrient uptake,growth, yield,and photosynthesis

Zucchini squash (Cucurbita pepo L.) plants were grown in a closed‐loop hydroponic system and supplied with nutrient solution (NS) containing NaCl at different concentrations (0.7, 3, 5, and 7 mM). The primary aim of the study was to define the relationship between the concentration of Na⁺ and Cl⁻ in the root zone solution and the respective Na⁺/water or Cl⁻/water uptake ratios (uptake concentrations, UC). A second objective was to determine the UC of macronutrients (i.e ., N, P, K, Ca, and Mg) and to test whether they are influenced by the gradual increase of the root zone salinity due to progressive NaCl accumulation. Two experiments were conducted, of which one (spring crop) was used to parameterize an existing empirical model, while the second one (autumn‐winter crop) was commissioned to test the validity of the determined model parameters. Both Cl⁻ and Na⁺ ions accumulated progressively in the root zone solution over time, showing a tendency to stabilize at final concentrations according to the corresponding NaCl treatment. The relationship between the Na⁺ and Cl⁻ concentrations in the root zone and the Na⁺/water or Cl⁻/water uptake ratios was exponential and the model parameters successfully fitted to data from crops cultivated in different growth seasons. This model may be used to monitor Na⁺ and Cl⁻ concentrations in the root environment of zucchini crops as relationships of the plant water consumption. The exposure of plants to NaCl affected the UC of N, K, Ca, and Mg, but the results for some nutrients were not consistent in both growth seasons. The measurements of plant growth characteristics (i.e ., biomass, yield, fruit quality, and photosynthesis) revealed that water resources containing up to 3 mM NaCl do not cause unacceptable yield losses in zucchini crops grown in completely closed hydroponic systems.     

High K+ supply avoids Na+ toxicity and improves photosynthesis by allowing favorable K+ : Na+ ratios through the inhibition of Na+ uptake and transport to the shoots of Jatropha curcas plants

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.     

Evaluation of Salinity Effects on Ionic Balance and Compatible Solute Contents in Nine Grape (Vitis L.) Genotypes

The salinity tolerance of nine grape genotypes was studied. Salinity was applied as nutrient solutions containing 0, 25, 50, and 100 mM sodium chloride (NaCl) for two weeks. Growth was significantly reduced by salinity, whereas chloride (Cl^?) and sodium (Na⁺) contents increased. Sodium ion accumulation exceeded that of Cl^? in all treatments. Shirazi and H₆ had higher and lower Cl^? concentrations in their lamina than others. There were significant positive correlations (P < 0.01) between Cl^? and Na⁺ and negative correlation between Na⁺ and potassium (K⁺) in roots and laminas of all genotypes. Soluble sugars, proline, and glycine betaine contents increased in laminas of all of the genotypes with moderate salinity. There were positive correlations (P < 0.01) between lamina and root Na⁺ and Cl^? contents and compatible solutes in all genotypes. Overall results revealed that unlike Shirazi with higher Na⁺ and Cl^? accumulation in shoot, H₆ showed a higher capacity to restrict Na⁺ and Cl^? transport to shoot.     

修复剂对镉污染盐渍化土壤植物修复效率的影响

目前,重金属污染盐渍化土壤已成为世界性的环境问题,利用盐生植物进行修复具有良好的环境与经济效益,但如何提高盐生植物修复效率的研究尚较少.采用盆栽试验方法,通过向土壤中施加氯化钠和氯化镉溶液分别模拟无污染非盐渍化土壤(Cd0S0)、NaCl型盐渍化土壤(Cd0S4)、重金属Cd污染土壤(Cd3S0)、重金属Cd污染NaC...     

Effect of different salts of sodium and potassium on the growth of Atriplex prostrata (Chenopodiaceae)

Although there are a variety of ions occurring in the soil throughout most of North America, the majority of halophyte literature focuses on the effects of NaCl on plants. In this study, a comparison is made of the effects of NaCl, KC1, Na₂SO₄, and K₂SO₄, on growth of the halophyte Atriplex prostrata Boucher ex DC (SYN: A. triangularis Willd.) at 0, ‐0.75, ‐1.00, and ‐1.50 MPa. Plant survival, height, number of leaves, nodes, and branches were recorded weekly. Photosynthesis was measured once before plants were harvested and dry mass was determined after one month. Content of Na⁺, K⁺,‐Mg²⁺, and Cl^‐ in plant tissue was also measured. A general trend observed was that all plant growth parameters decreased with a lowering of the medium osmotic potential, and that K⁺ salts were more inhibitory than Na⁺ salts. Ion content of plant tissue generally increased with a lowering of osmotic potential. Our data indicated that K⁺, a plant macronutrient, was more inhibitory to plant growth than Na⁺. It is possible that halophytes such as Atriplex prostrata could use Na⁺ as an osmoticum to adjust the vacuolar water potential, but were unable to use K⁺ for this function because of a specific ion toxicity. The inhibitory effect of salt on plant growth parameters and survival follow the pattern; K₂SO₄ >KCl>Na₂SO₄=NaCl.