Screening and identification of salt tolerance soybean varieties and germplasms

Soil salinization is a globally prevalent abiotic environmental stress.The imbalance of ions caused by high concentrations of sodium chloride results in a 40%reduction in soybean yield.Soybean,as an important crop for soil quality improvement,necessitates the identification of salt-tolerant varieties and germplasms to effectively utilize and enhance saline-alkali land.In this study,we assessed the salt tolerance of 435 soybean varieties and germplasms during the seedling stage.Among them,Qihuang34,You2104,Hongzhudou,Pamanheidou,and Osage exhibited grade 1 salt tolerance rates surpassing other tested materials.Furthermore,Hongzhudou and Qihuang34 demonstrated higher salt tolerance during germination and emergence stages based on their elevated rates of emergence,salt tolerance index,chlorophyll content,and shoot fresh weights.Overall findings provide valuable resources for molecular breeding efforts aimed at developing salt-tolerant soybean varieties suitable for cultivation in saline-alkali soils.

Multidimensional evaluation of salt tolerance in groundnut genotypes through biochemical responses

The manuscript explores the complex interplay between groundnut genotypes,salt tolerance and hormonal influence,shedding light on the dynamic responses of three specific groundnut genotypes,KDG-128,TG-37 A and GG-20,to salt treatments and gibberellic acid(GA3).The study encompasses germination,plant growth,total protein content and oil content as key parameters.Through comprehensive analysis,it identifies TG-37 A and KDG-128 as salt-tolerant genotypes,and GG-20 as salt-susceptible genotypes,which highlighting the potential for targeted breeding efforts to develop more resilient groundnut varieties.Moreover,the quantification of protein and oil content under different treatments provides vital data for optimizing nutritional profiles in groundnut cultivars.Principal Component Analysis(PCA) underscores the significance of the first principal component(PC1)in explaining the majority of variance,capturing primary trends and differences in plant length.Analysis of Variance(ANOVA) and hierarchical analysis confirm the presence of statistically significant differences in protein and oil content among the genotypes.Pearson's correlation coefficient matrix analysis reveals strong positive correlations between plant length and protein content,plant length and oil content,and a moderately positive correlation between protein content and oil content.These findings provide valuable insights into groundnut physiology,salt tolerance,and nutritional composition,with implications for future research in sustainable agriculture and crop improvement.

Soaking Rice Seeds in High Concentration Salt Solution Improved Salt Tolerance at the Seedling Stage

[Objectives]This study was conducted to enhance the salt tolerance of current rice varieties at the seedling stage and fulfill the urgent requirement for salt-tolerant rice varieties in coastal tidal flats.[Methods]Four high-generation stable rice lines with diverse salt tolerance were employed as test materials,and four NaCl concentration gradients were established for seed soaking treatment.[Results]The seedling survival rate of line 151465 underwent significant alterations after soaking with four different salt concentrations,and the survival rate was the highest after treatment with 1.8%NaCl for 1 d,reaching 65.2%.The average survival rate of other three lines with different salt tolerance reached 62%after soaking with 1.8%NaCl for 1 d,which was significantly higher than those of the 2.2%NaCl and 0%NaCl treatments.[Conclusions]This study provides a basis for reducing the effect of abiotic stress on rice growth and development and improving the utilization rate of saline-alkali land.

OsMas1,a novel maspardin protein gene,confers tolerance to salt and drought stresses by regulating ABA signaling in rice

Drought and salt stresses,the major environmental abiotic stresses in agriculture worldwide,affect plant growth,crop productivity,and quality.Therefore,developing crops with higher drought and salt tolerance is highly desirable.This study reported the isolation,biological function,and molecular characterization of a novel maspardin gene,OsMas1,from rice.The OsMas1 protein was localized to the cytoplasm.The expression levels of OsMas1 were up-regulated under mannitol,PEG6000,NaCl,and abscisic acid(ABA) treatments in rice.The OsMas1 gene was introduced into the rice cultivar Zhonghua 11(wild type,WT).OsMas1-overexpression(OsMas1-OE) plants exhibited significantly enhanced salt and drought tolerance;in contrast,OsMas1-interference(OsMas1-RNAi) plants exhibited decreased tolerance to salt and drought stresses,compared with WT.OsMas1-OE plants exhibited enhanced hypersensitivity,while OsMas1-RNAi plants showed less sensitivity to exogenous ABA treatment at both germination and post-germination stages.ABA,proline and K+ contents and superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),and photosynthesis activities were significantly increased.In contrast,malonaldehyde(MDA),hydrogen peroxide(H2O2),superoxide anion radical(O2-··),and Na+ contents were significantly decreased in OsMas1-OE plants compared with OsMas1-RNAi and WT plants.Overexpression of OsMas1 up-regulated the genes involved in ABA signaling,proline biosynthesis,reactive oxygen species(ROS)-scavenging system,photosynthesis,and ion transport under salt and drought stresses.Our results indicate that the OsMas1 gene improves salt and drought tolerance in rice,which may serve as a candidate gene for enhancing crop resistance to abiotic stresses.

Advances in deciphering salt tolerance mechanism in maize

Maize(Zea mays L.)is a global cereal crop whose demand is projected to double by 2050.Along with worsening of farmland salinization,salt stress has become a major environmental threat to the sustainability of maize production worldwide.Accordingly,there is an urgent need to decipher salt-tolerant mechanisms and facilitate the breeding of salt-tolerant maize.As salt tolerance is a complex trait regulated by multiple genes,and maize germplasm varies widely in salt tolerance,efforts have been devoted to the identification and application of quantitative-trait loci(QTL)for salt tolerance.QTL associated with ion regulation,osmotic tolerance,and other aspects of salt tolerance have been discovered using genomewide association studies(GWAS),linkage mapping,and omics-based approaches.This review highlights recent advances in the molecular-level understanding of salt stress response in maize,in particular in(a)the discovery of salt-tolerance QTL,(b)the mechanisms of salt tolerance,(c)the development of salttolerant maize cultivars,and(d)current challenges and future prospects.

Calcium/calmodulin modulates salt responses by binding a novel interacting protein SAMS1 in peanut(Arachis hypogaea L.)

The Ca^(2+)/CaM signal transduction pathway helps plants adapt to environmental stress. However, our knowledge on the functional proteins of C^(2+)/CaM pathway in peanut(Arachis hypogeae L.) remains limited. In the present study, a novel calmodulin 4(CaM4)-binding protein S-adenosyl-methionine synthetase 1(SAMS1) in peanut was identified using a yeast two-hybrid assay. Expression of AhSAMS1was induced by Ca^(2+), ABA, and salt stress. To elucidate the function of AhSAMS1, physiological and phenotypic analyses were performed with wild-type and transgenic materials. Overexpression of AhSAMS1increased spermidine and spermidine synthesis while decreased the contents of ethylene, thereby eliminating excessive reactive oxygen species(ROS) in transgenic lines under salt stress. AhSAMS1 reduced uptake of Na+and leakage of K+from mesophyll cells, and was less sensitive to salt stress during early seedling growth, in agreement with the induction of SOS and NHX genes Transcriptomics combined with epigenetic regulation uncovered relationships between differentially expressed genes and differentially methylated regions, which raised the salt tolerance and plants growth. Our findings support a model in which the role of AhSAMS1 in the ROS-dependent regulation of ion homeostasis was enhanced by Ca^(2+)/CaM while AhSAMS1-induced methylation was regulated by CaM, thus providing a new strategy for increasing the tolerance of plants to salt stress.

SlTPP4 participates in ABA-mediated salt tolerance by enhancing root architecture in tomato

Salinity tolerance is an important physiological index for crop breeding.Roots are typically the first plant tissue to withstand salt stress.In this study,we found that the tomato(Solanum lycopersicum)trehalose-6-phosphate phosphatase(SlTPP4)gene is induced by abscisic acid(ABA)and salt,and is mainly expressed in roots.Overexpression of SlTPP4 in tomato enhanced tolerance to salt stress,resulting in better growth performance.Under saline conditions,SlTPP4 overexpression plants demonstrated enhanced sucrose metabolism,as well as increased expression of genes related to salt tolerance.At the same time,expression of genes related to ABA biosynthesis and signal transduction was enhanced or altered,respectively.In-depth exploration demonstrated that SlTPP4 enhances Casparian band development in roots to restrict the intake of Na^(+).Our study thus clarifies the mechanism of SlTPP4-mediated salt tolerance,which will be of great importance for the breeding of salt-tolerant tomato crops.

A cluster of mutagenesis revealed an osmotic regulatory role of the OsPIP1 genes in enhancing rice salt tolerance

Aquaporins play important regulatory roles in improving plant abiotic stress tolerance.To better understand whether the Os PIP1 genes collectively dominate the osmotic regulation in rice under salt stress,a cluster editing of the Os PIP1;1,Os PIP1;2 and Os PIP1;3 genes in rice was performed by CRISPR/Cas9 system.Sequencing showed that two mutants with Cas9-free,line 14 and line 18 were successfully edited.Briefly,line 14 deleted a single C base in both the Os PIP1;1 and Os PIP1;3 genes,and inserted a single T base in the Os PIP1;2 gene,respectively.While line 18 demonstrated an insertion of a single A base in the Os PIP1;1gene and a single T base in both the Os PIP1;2 and Os PIP1;3 genes,respectively.Multiplex editing of the Os PIP1 genes significantly inhibited photosynthetic rate and accumulation of compatible metabolites,but increased MDA contents and osmotic potentials in the mutants,thus delaying rice growth under salt stress.Functional loss of the Os PIP1 genes obviously suppressed the expressions of the Os PIP1,Os SOS1,Os CIPK24 and Os CBL4 genes,and increased the influxes of Na+and effluxes of K^(+)/H^(+)in the roots,thus accumulating more Na+in rice mutants under salt stress.This study suggests that the Os PIP1 genes are essential modulators collectively contributing to the enhancement of rice salt stress tolerance,and multiplex editing of the Os PIP1 genes provides insight into the osmotic regulation of the PIP genes.

The Improvement of Soybean Salt Tolerance by Overexpressed GmPAO1

Polyamines play an important regulatory role during plant growth and development and adversity stress,and polyamine oxidase(PAO)is involved in polyamine catabolism.In this study,an up-regulated polyamine oxidase gene GmPAO1 was obtained by transcriptome sequencing analysis and screening at soybean seedling stages.Also,its expression pattern and function were analyzed.The identification results of transgenic GmPAO1 soybean positive lines showed that the relative expression level of GmPAO1 in the overexpressed lines was increased under salt stress.With increasing stress concentration,the seed germination rate decreased.However,the seed germination rate of the overexpressed lines was significantly higher than that of the control lines,and the phenotypic character of the root systems was also better than that of the control lines.The measurement of superoxide dismutase(SOD)and peroxidase(POD)activities and malondialdehyde and hydrogen peroxide contents revealed that the overexpressed soybean lines significantly increased the SOD and POD activities,significantly reducing the malondialdehyde content.Although the hydrogen peroxide content in the transformed plants gradually increased,the hydrogen peroxide content in the overexpression lines was still lower than that in the gene editing lines.Based on this,it was preliminarily judged that GmPAO1 can improve soybean salt tolerance.

Temperature/salt tolerance and oil recovery of xanthan gum solution enhanced by surface-modified nanosilicas

Amide-and alkyl-modified nanosilicas(AANPs)were synthesized and introduced into Xanthan gum(XG)solution,aiming to improve the temperature/salt tolerance and oil recovery.The rheological behaviors of XG/AANP hybrid dispersions were systematically studied at different concentrations,temperatures and inorganic salts.At high temperature(75C)and high salinity(10,000 mg,L1 NaCl),AANPs increase the apparent viscosity and dynamic modulus of the XG solution,and XG/AANP hybrid dispersion exhibits elastic-dominant properties.The most effective concentrations of XG and AANP interacting with each other are 1750 mg·L^(-1) and 0.74 wt%,respectively.The temperature tolerance of XG solution is not satisfactory,and high temperature further weakens the salt tolerance of XG.However,the AANPs significantly enhance the viscoelasticity the XG solution through hydrogen bonds and hydrophobic effect.Under reservoir conditions,XG/AANP hybrid recovers approximately 18.5%more OOIP(original oil in place)than AANP and 11.3%more OOIP than XG.The enhanced oil recovery mechanism of the XG/AANP hybrid is mainly increasing the sweep coefficient,the contribution from the reduction of oil-water interfacial tension is less.

Wide temperature range-and damage-tolerant microsupercapacitors from salt-tolerant, anti-freezing and self-healing organohydrogel via dynamic bonds modulation

The advance of microelectronics requires the micropower of microsupercapacitors(MSCs) to possess wide temperature-and damage-tolerance beyond high areal energy density.The properties of electrolyte are crucial for MSCs to meet the above requirements.Here,an organohydrogel electrolyte,featured with high salt tolerance,ultralow freezing point,and strong self-healing ability,is experimentally realized via modulating its inner dynamic bonds.Spectroscopic and theoretical analysis reveal that dimethyl sulfoxide has the ability to reconstruct Li^(+)solvation structure,and interact with free water and polyvinyl alcohol chains via forming hydrogen bonds.The organohydrogel electrolyte is employed to build MSCs,which show a boosted energy density,promising wide temperature range-and damage-tolerant ability.These attractive features make the designed organohydrogel electrolyte have great potential to advance MSCs.

Eco-friendly aqueous foam stabilized by cellulose microfibers with great salt tolerance and high temperature resistance

A low-cost eco-friendly aqueous foam,especially the robust foam with great tolerance to high salinity and high temperature,is in great demand in the oil industry,e.g.,oil and gas well or geothermal well drilling.Herein,an ultra-stable aqueous foam was developed using the biodegradable cellulose microfiber(CMF)as a foam stabilizer.The foam stabilized by CMF shows excellent tolerance to the high concentration of NaCl(6.0 wt%)and CaCl_(2)(0.25 wt%)and the related drainage half-life times(T_(0.5))reach 1750 and 2340 s respectively.By contrast,the foams without CMF are completely drained(T_(0.5)=0 s)when NaCl concentration is greater than 6.0 wt%or CaCl_(2) concentration is greater than 0.20 wt%.Notably,T0.5 of the foams stabilized by CMF at these saline concentrations still can maintain above 1000 s even after aging at 120℃ for 16 h,exhibiting an outstanding foam-stabilizing performance at high temperature.Experimental results suggest that the salt and high-temperature tolerance of CMF in foam stabilization is attributed to the electrically uncharged surfaces,the formation of a gel-like structure and the excellent thermal stability.This work not only provides a promising candidate of aqueous foam stabilizer to deal with high temperature and high salinity but also presents a natural-based solution for an environmentally friendly drilling industry in the future.

In vitro Evaluation of Seed Germination in Twelve Alfalfa Cultivars under Salt Stress

Alfalfa(Medicago sativa L.),when exposed to abiotic stress such as salinity,suffers significant losses in yield and productivity.The present study evaluated the salinity tolerance of 12 alfalfa cultivars in vitro using five concentrations of sodium chloride(NaCl),ranging from 0 to 250 mmol L^(−1).The results obtained in the current study revealed that the Saudi cultivars,Kasimi and Hassawi,and the German cultivar(Berlin)had the highest salinity tolerance in terms of germination percentage(GP),corrected germination rate index(CGRI),days to reach 50%germination(GT_(50)),and ability to form cotyledonary and true leaves.Under mmol L^(−1) NaCl,the Saudi cultivar Kasimi cultivar showed GP,CGRI,and GT_(50) of 55.20%,123.15,and 3.77 days,respectively.Similarly,the German cultivar(Berlin)showed GP,CGRI,and GT_(50) of 50.06%,86.61,and 5.17 days,respectively.These findings might reveal a pivotal aspect in salt tolerance in alfalfa.Our results will help to select salt-tolerant alfalfa cultivars that could thrive in arid and semi-arid areas with salinity problems.

Physiological and Biochemical Characteristics and Response Patterns of Salinity Stress Responsive Genes (SSRGs) in Wild Quinoa (Chenopodium quinoa L.)

Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils.Quinoa,a protein-comprehensive cereal in the plant kingdom,is an exceptional crop in terms of salt stress tolerance level.It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms.In this study,the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution.The physiological,biochemical characteristics and agronomic traits were investigated,and the response patterns of three salt stress-responsive genes(SSRGs)in quinoa were determined by real-time PCR.The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl.Salt stress significantly induced expression of superoxide dismutase(SOD),peroxidase(POD),and particularly betaine aldehyde dehydrogenase(BADH).BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings,particularly at high NaCl concentrations,as it displayed upregulation until 24 h under 100 mM salt treatment.Moreover,it showed upregulation until 12 h under 250 mM salt stress.Taken together,these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa.Based on the expression level and prompt response induced by NaCl,we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development.Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth.Therefore,an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm,which is useful to the utilization of saline soils.Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.

Genetic linkage mapping and QTL identification for salinity tolerance in Indian mustard(Brassica juncea L.Czern and Coss.)using SSR markers

Soil salinity is one of the major environmental constraints that limits crop yield and nearly 7%of the total area worldwide is affected by salinity.Salinity-induced oxidative stress causes membrane damage during germination and seedling growth.Indian mustard is a major oilseed crop in India and its production and productivity are severely affected by salt stress.Breeding Brassica cultivars for salinity tolerance by conventional means is very difficult and time-consuming.Therefore,understanding the molecular components associated with salt tolerance is needed to facilitate breeding for salt tolerance in Brassica.In this investigation,quantitative trait loci(QTLs)associated with salt tolerance were identified using F_(2:3)mapping population developed from a cross between CS52(salinity tolerant)and RH30(salinity sensitive).Parents and F_(2:3)were evaluated under controlled and salinity stress conditions for 14 morpho-physiological traits for two consecutive generations(F2 and F_(2:3)),explaining proportion of the phenotypic variance under control condition.Simple sequence repeat(SSR)markers were used for mapping studies.A genetic linkage map based on 42 simple sequence repeats(SSRs)markers was constructed covering 2298.5 cM(Haldane)to identify the loci associated with salt tolerance in Brassica juncea.Forty-one SSRs showing polymorphism in the parents(CS52 and RH30)were mapped on 8 linkage groups(C1–C8).One marker(nga 129)did not map to any of the linkage group and was excluded from mapping.Linkage group 5(C5;317.9 cM)was longest and linkage group 1(C1,255.0 cM)was shortest.Further,we identified 15 QTLs controlling 8 traits using F_(2:3)population.These QTLs explained 12.44–60.63%of the phenotypic variation with a LOD score range of 3.62–5.97.Out of these QTLs,QMI4.1 related to membrane injury showed 51.28%phenotypic variance with a LOD score of 3.34.QTL QBYP8.1 related to biological yield per plant showed 60.63%phenotypic variance at a LOD score of 3.62.The highest LOD score of 5.97 was recorded for QTL related to seed yield per plant(QSYP4.1).Major QTLs were QTL for biological yield per plant(QBYP8.1),QTL for siliquae per plant(QSP4.1),QTL for primary branches(QPB4.1),QTLs for seed per siliqua(QSS4.1,QSS4.2),QTL for seed yield per plant(QSYP4.1),and QTL for membrane injury(QMI8.1)which showed more than 50%phenotypic variance.These QTLs identified in our study need to be confirmed in other populations as well so that these can be used in marker-assisted selection and breeding to enhance salt tolerance in Brassica juncea.

Cloning of cDNA Encoding Choline Monooxygenase from Suaeda liaotungensis and Salt Tolerance of Transgenic Tobacco

Betaine is a very effective osmoprotectant found in many organisms. In high plants, betaine is synthesized by oxidation of choline in two sequential steps: choline-->betaine aldehyde-->betaine. The first step is catalyzed by choline monooxygenase (CMO). In this study, the full-length CMO cDNA (1 820 bp) was cloned from halophyte Suaeda liaotungensis Kitag by RT-PCR and RACE. It included a 123 bp 5' UTR, a 368 bp 3' UTR and a 1 329 bp open reading frame encoding a 442-amino-acid polypeptide with 77%, 72% and 74% sequence identity compared to CMOs from spinach, sugar beet and Atriplex hortensis, respectively. The CMO open reading frame (ORF) was cloned and the plant expression vector pBI121-CMO was constructed. It was transferred into tobacco ( Nicotiana tabacum L. ev. 89) via Agrobacterium mediation. PCR and Southern blotting analysis showed that the CMO gene was integrated into tobacco genome. Transgenic tobacco plants contained higher amount of betaine than that of control plants and were able to survive on MS medium containing 250 mmol/L NaCl. Relative electronic conductivity demonstrated less membrane damage in transgenic plants as in the wild type.

Relationship Between Polyamine Metabolism in Roots and Salt Tolerance of Barley Seedlings

Plant growth rate (GR), contents of free polyamines (fPAs) and bound polyamines (bPAs) and activities of some key enzymes involved in polyamine (PA) metabolism in the roots of two barley (Hordeum valgare L.) cultivars differing in salt sensitivity were investigated with 0-300 mmol/L NaCl treatments. With 0-200 mmol/L NaCl treatments, activities of arginine decarboxylase (ADC) and transglutaminase (TGase) and PA oxidase (PAO) in the roots of barley seedlings all increased, while TGase and PAO activities decreased slightly at 300 mmol/L NaCl. As a result, free Put (fPut) content increased continuously with increasing concentrations of NaCl, while levels of free Spd (fSpd) and an unknown PA (fPAx) and bPAs (bPut, bSpd and bPAx), as well as (fSpd + fPAx)/fPut ratio rose at 50-200 mmol/L NaCl and reduced at 300 mmol/L NaCl. However, no significant change in the tetra-amine spermine (Spin) content was observed. Statistical analysis showed that GR was very significantly positively correlated with (fSpd + fPAx)/fPut ratios and the contents of bPAs, whereas a significant inverse correlation existed between GR and the ratios of fPA contents to bPA levels. These results showed that, under salt stress, the balance between fSpd, fPAx and fPut levels and an equipoise between fPA and bPA contents in roots were important to salt tolerance of barley seedlings.

Comparison of Some Characteristics Between Phragmites communis and Its Salt Tolerant Variant

R5002_12, a salt tolerant line of Phragmites communis Trin., which was obtained from ethyl methane sulfonate (EMS) treated callus selected under saline stress, was compared with its wild line in respect to their molecular biological, physiological and biochemical characterizations. Five arbitrary primers were screened which showed differences in DNA amplified polymorphism between the variant and its wild line. Some new proteins appeared in the salt tolerant plant under salt stress. Electrophoresis of peroxidase and esterase also showed some differences in isozyme expression between them. The chlorophyll content of the variant was higher than that of the original variety, whether the plants were under salt stress or not.

Application of Fuzzy Comprehensive Evaluation Method Based on Entropy Weight Theory in Evaluation of Salt Tolerance of Cotton

[Objective] The aim was to propose a new entropy weight fuzzy compre- hensive evaluation method for assessing cotton salt tolerance, realizing the objective, accurate and comprehensive evaluation of salt tolerance of cotton. [Method] A sand culture experiment under salt stress of 150 mmol/L of NaCI was designed. The in- dicator weight was determined with the entropy weight fuzzy comprehensive evalu- ation method, based on the salt injury index of indicators. The salt tolerance of cotton was evaluated comprehensively. [Result] At the germination stage, the entropy and weight of salt injury index of germination energy, vigor index, hypocotyl length and fresh weight were highest, followed by germination rate and germination index, and of root length were lowest. At the seedling stage, the entropy and weight of salt injury index of plasma membrane permeability, root vigor and leaf expansion rate were highest, followed by plant height and net photosynthetic rate, and of shoot dry weight and root dry weight were lowest. The salt tolerance of cotton differed a- mong growth stages and cultivars. Among the 11 cultivars, CCRI-44 and CCRI-75 were steadily salt-tolerant at both germination and seedling stages; CCRI-17, Sumi- an 22, Sumian 15 and Dexiamianl had a stable moderate salt tolerance; while Sumian 12 and Simian 3 were steadily salt-sensitive. [Conclusion] The evaluated result was objective and exact, which indicated that this method could be used in comprehensive evaluation of salt tolerance of cotton.

Relationship Between Tonoplast H^+-ATPase Activity, Ion Uptake and Calcium in Barley Roots Under NaCl Stress

Under NaCl stress for 2 d, H+-ATPase activity increased, and H+-PPase activity decreased in the tonoplast of salt-tolerant barley ( Hordeum vulgare L. cv. 'Tanyin 2') roots. La3+ (1 mmol/L), an inhibitor of Ca2+ channel in plasma membrane, and EGTA (5 mmol/L), a Ca2+ chelator, inhibited this NaCl-induced increase in H+-ATPase activity but stimulated the H+-PPase activity. Treatment of barley roots with CaM antagonist (trifluoperazine, TFP, 20 mumol/L) also diminished the increase of H+-ATPase activity induced by NaCl. La3+, TFP or La3+ + TFP increased Na+ uptake and decreased K+ and Ca2+ uptake in barley roots under NaCl stress. These results suggested that the activation of tonoplast H+-ATPase and the regulation of Na+ and K+ uptake under NaCl stress may be related to Ca2+-CaM system.