Na2CO3 Stress Research Articles

Effects of alkaline salt stress on growth, physiological properties and medicinal components of clonal Glechoma longituba (Nakai) Kupr.

BackgroundGlechoma longituba, recognized as a medicinal plant, provides valuable pharmaceutical raw materials for treating various diseases. Saline-alkali stress may effectively enhance the medicinal quality of G. longituba by promoting the synthesis of secondary metabolites. To investigate the changes in the primary medicinal components of G. longituba under saline-alkali stress and improve the quality of medicinal materials, Na2CO3 was applied to induce short-term stress under different conditions and the biomass, physiologically active substances and primary medicinal components of G. longituba were measured in this study.ResultsUnder alkaline salt stress, the activities of catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) were elevated in G. longituba, accompanied by increased accumulation of proline (Pro) and malondialdehyde (MDA). Furthermore, analysis of the medicinal constituents revealed that G. longituba produced the highest levels of soluble sugars, flavonoids, ursolic acid, and oleanolic acid under 0.6% Na2CO3 stress for 48 h, 0.2% Na2CO3 stress for 72 h, 0.4% Na2CO3 stress for 12 h, and 0.4% Na2CO3 stress for 8 h, respectively.ConclusionsShort-term Na2CO3 stress enhances the synthesis of medicinal components in G. longituba. By manipulating stress conditions, the production of various medicinal substances could be optimized. This approach may serve as a basis for the targeted cultivation of G. longituba, offering potential applications in the treatment of diverse diseases.

Exogenous Melatonin Reinforces Photosynthesis, Antioxidant Defense and Gene Expression to Ameliorate Na2CO3 Stress in Maize.

Salt stress can seriously affect the growth and development of maize (Zea mays L.), resulting in a great yield loss. Melatonin (MT), an indole hormone, is a potential enhancer of plant tolerance against salt stress. However, the complex mechanisms of MT application in enhancing maize salt tolerance are still unclear. Herein, three-leaf seedlings of salt-susceptible P138 and its salt-resistant ethyl methane sulfonate (EMS)-104 mutant were cultured with or without 150 μM MT application under 0 and 100 mM Na2CO3 treatments for seven days, to systematically explore the response mechanisms of exogenous MT in improving the salt tolerance of maize. The results showed that salt stress triggered an escalation in reactive oxygen species production, enhanced multiple antioxidant enzymes' activities, impaired cellular membrane permeability, inhibited photosynthetic pigment accumulation, and ultimately undermined the vigor and photosynthetic prowess of the seedlings. While suitable MT application counteracted the detrimental impacts of Na2CO3 on seedlings' growth and photosynthetic capacity, the seedling length and net photosynthetic rate of P138 and EMS-104 were increased by 5.5% and 18.7%, and 12.7% and 54.5%, respectively. Quantitative real-time PCR (qRT-PCR) analysis further showed that MT application activated the expression levels of antioxidant enzyme-related genes (Zm00001d025106, Zm00001d031908, Zm00001d027511, and Zm00001d040364) and pigment biosynthesis-related genes (Zm00001d011819 and Zm00001d017766) in both maize seedlings under Na2CO3 stress; they then formed a complex interaction network of gene expression, multiple physiological metabolisms, and phenotype changes to influence the salt tolerance of maize seedlings under MT or Na2CO3 stress. To sum up, these observations underscore that 150 μM MT can alleviate salt injury of maize seedlings, which may provide new insights for further investigating MT regulation mechanisms to enhance maize seedlings' salt resistance.

Specific physiological responses to alkaline carbonate stress in rice (Oryza sativa) seedlings: organic acid metabolism and hormone signalling

In recent years, alkaline soda soil has stimulated numerous biological research on plants under carbonate stress. Here, we explored the difference in physiological regulation of rice seedlings between saline (NaCl) and alkaline carbonate (NaHCO3 and Na2CO3) stress. The rice seedlings were treated with 40 mM NaCl, 40 mM NaHCO3 and 20 mM Na2CO3 for 2 h, 12 h, 24 h and 36 h, their physiological characteristics were determined, and organic acid biosynthesis and metabolism and hormone signalling were identified by transcriptome analysis. The results showed that alkaline stress caused greater damage to their photosynthetic and antioxidant systems and led to greater accumulation of organic acid, membrane damage, proline and soluble sugar but a decreased jasmonic acid content compared with NaCl stress. Jasmonate ZIM-Domain (JAZ), the probable indole-3-acetic acid-amido synthetase GH3s, and the protein phosphatase type 2Cs that related to the hormone signalling pathway especially changed under Na2CO3 stress. Further, the organic acid biosynthesis and metabolism process in rice seedlings were modified by both Na2CO3 and NaHCO3 stresses through the glycolate/glyoxylate and pyruvate metabolism pathways. Collectively, this study provides valuable evidence on carbonate-responsive genes and insights into the different molecular mechanisms of saline and alkaline stresses.

Physiological and Biochemical Responses of Melilotus albus to Saline and Alkaline Stresses

Sweet clover (Melilotus albus) is a high-quality leguminous forage grass with salinity tolerance, drought tolerance, and cold hardiness. We selected four varieties of sweet clover with different sensitivities (061898, 061930, No. 55 white flower, and Ningxia white flower) and analyzed the effects of different concentrations of three sodium salts (Na2CO3, NaHCO3, and NaCl) on their physiology and biochemistry responses. Growth and development indexes (such as germination rate, root length, shoot length), chlorophyll content, osmotic regulators (proline, soluble sugar), malondialdehyde (MDA), superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were determined under saline–alkali stress. Seed germination and seedling growth of all four clover species were significantly inhibited under saline–alkali stress. During germination, seed germination rate, root length, and shoot length decreased with increasing saline and alkaline concentration. Under saline–alkali stress, chlorophyll content tended to increase and then decrease, cell damage and death increased, and malondialdehyde, soluble sugar, and proline content tended to increase and then decrease. Moreover, the activities of SOD, POD, and CAT all increased and then decreased. Under Na2CO3 stress, the decrease in chlorophyll content of the resistant variety 061898 was less than in the sensitive Ningxia white flower variety. As the concentrations of Na2CO3, NaHCO3, and NaCl increased, the maximum photochemical efficiency of PSII was significantly affected. The resistant 061898 is capable of maintaining higher photosynthetic efficiency. Furthermore, under treatments with the three kinds of saline–alkali solutions, cell damage and death for Ningxia white flower were greater than in 061898. For 061898, the increases in soluble sugar and proline content were greater and the increase in malondialdehyde content was less, while the antioxidant enzyme activities were higher than those in Ningxia white flower. All four sweet clover varieties had higher stress resistance with neutral than with alkaline salts. When stressed by medium to high saline–alkali concentrations, sweet clover seedlings had increased osmotic substance content, enhanced antioxidant enzyme activity, and regulated physiological metabolism. Additionally, sweet clovers regulated the expression of WRKY33, GH3, CYCD3, OXI1, MKK2, MYC2, JAZ, COI1, PYL, PP2C, TGA, and MPK3 to adapt to the saline–alkali environment and improve saline–alkali tolerance. Our analysis of the sweet clover salinity tolerance mechanism contributes to its further use and is of significant importance for addressing land salinization and promoting sustainable agricultural and pastoral practices in China.

Enhancing stimulation of cyaniding, GhLDOX3 activates reactive oxygen species to regulate tolerance of alkalinity negatively in cotton

Anthocyanins belong to flavonoid secondary metabolites that act as plant pigments to give flowers and fruits different colors and as "scavengers" of reactive oxygen species (ROS) to protect plants from abiotic and biotic stresses. Few studies linked anthocyanins to alkaline resistance so far. In this study, anthocyanin synthesis-related gene leucoanthocyanidin dioxygenase (LDOX) was screened as a candidate gene to explore its relationship with alkali stress. The results found that pYL156: GhLDOX3 lines treated with 50 mM Na2CO3 (pH 11.11) for 24 h showed a significant increase in peroxidase (POD) activity, a decrease in total anthocyanin content and an increase in cyanidin content and a decrease in ROS accumulation compared to pYL156. The overexpressed (OE) lines, ldox mutant and wild-type (WT) lines in Arabidopsis were treated with 50 mM Na2CO3, 100 mM Na2CO3 and 150 mM Na2CO3 for 8 d, respectively. The wilted degree of the OE lines was more severe than WT lines, and less severe in the mutant lines in the 150 mM Na2CO3 treatment. After treatment, the expression levels of AtCAT and AtGSH genes related to antioxidant system in OE lines were significantly lower than in WT, and the expression levels of AtCAT and AtGSH in mutant lines were significantly higher than in WT. In conclusion, the above results suggest GhLDOX3 played a negative regulatory role in the mechanism of resisting Na2CO3 stress. Therefore, it can be considered in cotton breeding to improve the alkali tolerance of cotton by regulating the expression of related genes.

Seed Germination and Seedling Growth in Suaeda salsa (Linn.) Pall. (Amaranthaceae) Demonstrate Varying Salinity Tolerance among Different Provenances.

Salinity is a pressing and widespread abiotic stress, adversely affecting agriculture productivity and plant growth worldwide. Seed germination is the most critical stage to seedling growth and establishing plant species in harsh environments, including saline stress. However, seed germination characteristics and stress tolerance may vary among geographical locations, such as various provenances. Suaeda salsa (Linn.) Pall. (S. salsa) is a halophytic plant that exhibits high salt tolerance and is often considered a pioneer species for the restoration of grasslands. Understanding the germination characteristics and stress tolerance of the species could be helpful in the vegetation restoration of saline-alkali land. In this study, we collected S. salsa seeds from seven different saline-alkali habitats (S1-S7) in the Songnen Plain region to assess the germination and seedling growth responses to NaCl, Na2CO3, and NaHCO3, and to observe the recovery of seed germination after relieving the salt stress. We observed significant differences in germination and seedling growth under three salt stresses and among seven provenances. Resistance to Na2CO3 and NaHCO3 stress was considerably higher during seedling growth than seed germination, while the opposite responses were observed for NaCl resistance. Seeds from S1 and S7 showed the highest tolerance to all three salt stress treatments, while S6 exhibited the lowest tolerance. Seeds from S2 exhibited low germination under control conditions, while low NaCl concentration and pretreatment improved germination. Ungerminated seeds under high salt concentrations germinated after relieving the salt stress. Germination of ungerminated seeds after the abatement of salt stress is an important adaptation strategy for black S. salsa seeds. While seeds from most provenances regerminated under NaCl, under Na2CO3 and NaHCO3, only seeds from S4 and S7 regerminated. These findings highlight the importance of soil salinity in the maternal environment for successful seed germination and seedling growth under various salinity-alkali stresses. Therefore, seed sources and provenance should be considered for vegetation restoration.

Physiological responses and adoptive mechanisms in oat against three levels of salt stress

To identify the propagation mechanisms and the adaptive strategies of oat seedlings exposed to NaCl, NaHCO3 and Na2CO3 the main salts in the soils of the salt-alkali grasslands of the Songnen Plain of China, growth rates and physiological indices of oat seedlings were measured in plants grown in soils with different concentrations (48-144 mmol L-1) of the three salts. The results demonstrated that although oat seedlings survival rates were unaffected by NaCl stress, the tiller number, plant height, and shoot and root dry weights decreased with increasing salt concentration, in the order of Na2CO3＞NaHCO3＞NaCl. In addition, propagation mechanisms higher concentrations of Na+ accumulated in the shoots and roots of oat seedlings under Na2CO3 stress and NaHCO3 stress than in seedlings under NaCl stress. Reductions in concentrations of K+ were also greater under both Na2CO3 and NaHCO3 stress than NaCl, especially in the roots. Large amounts of Cl－ and proline were found to accumulate in oat seedlings, most likely as a strategy for maintaining osmotic and ionic homeostasis under NaCl stress.

Transcriptome-Based Comparative Analysis of Transcription Factors in Response to NaCl, NaOH, and Na2CO3 Stresses in Roots of Autotetraploid Rice (Oryza sativa L.)

Soil salinity is a severe constraint on crop productivity that triggers plant salt stress response pathways. The salt stress responses are controlled by transcriptional regulatory networks that enhance plant stress tolerance by manipulating the expression of transcription factor (TFs)-encoding genes. Identifying TFs associated with salt tolerance contributes to salt-tolerant crop breeding. In this study, a comparative transcriptome analysis was performed to investigate the global gene expression of entire TFs in diploid and autotetraploid rice with different salt tolerance levels, considering NaCl stress, NaOH stress, and Na2CO3 stress. A total of 54, 54 and 55 TF families were co-expressed in diploid and tetraploid roots under three stresses, respectively. Furthermore, we investigated differentially expressed TFs (DE-TFs) based on different comparisons, and the statistical analysis indicated that the DE-TFs derived from the three types of stress were as follows: Na2CO3 (53 TF families, 1356 DE-TFs) > NaCl (19 TF families, 214 DE-TFs) > NaOH (18 TF families, 152 DE-TFs). These results imply that Na2CO3 stress induced a more obvious biological responses in the roots than the other two stresses. GO and KEGG pathway enrichment analysis of DE-TFs revealed the importance of plant hormone signal transduction and MAPK signaling pathways that may contribute to the saline–alkaline tolerance of tetraploid rice. This study provides gene resources that are valuable for exploring the regulatory mechanism of TFs involved in the saline–alkaline tolerance of polyploid rice.

Application of RNA sequencing to understand the response of rice seedlings to salt-alkali stress

BackgroundSalt-alkali stress represents one of the most stressful events with deleterious consequences for plant growth and crop productivity. Despite studies focusing on the effects of salt-alkali stress on morphology and physiology, its molecular mechanisms remain unclear. Here, we employed RNA-sequencing (RNA-seq) to understand how Na2CO3 stress inhibits rice seedling growth.ResultsNa2CO3 stress significantly inhibited the growth of rice seedlings. Through RNA-seq, many differentially expressed genes (DEGs) were shown to be potentially involved in the rice seedling response to salt-alkali stress. After 1-day and 5-day treatments, RNA-seq identified 1780 and 2315 DEGs in the Na2CO3-treated versus -untreated rice seedling shoots, respectively. According to the gene ontology enrichment and the Kyoto Encylopedia of Genes and Genomes annotation of DEGs, the growth-inhibition processes associated with salt-alkali stress involve a myriad of molecular events, including biosynthesis and metabolism, enzyme activity, and binding, etc.ConclusionCollectively, the transcriptome analyses in the present work revealed several potential key regulators of plant response to salt-alkali stress, and might pave a way to improve salt-alkali stress tolerance in rice.

Alkaline Salt Inhibits Seed Germination and Seedling Growth of Canola More Than Neutral Salt.

Salinity is a major constraint to crop growth and productivity, limiting sustainable agriculture production. Planting canola (Brassica napus L.) variety with salinity-alkalinity tolerance as a green manure on the large area of salinity-affected land in Xinjiang could alleviate feed shortage. To investigate the differential effects of neutral and alkaline salt stress on seed germination and seedling growth of canola, we used two salts at varying concentrations, i.e., NaCl (neutral salt at 100, 150, and 200 mM) and Na2CO3 (alkaline salt at 20, 30, and 40 mM). To further explore the effects of Na+ and pH on seed germination, we included combined of NaCl (0, 100, 150, and 200 mM) and pH (7.1, 8.0, 9.0, 10.0, and 11.0). Shoot growth was promoted by low concentrations of NaCl and Na2CO3 but inhibited at high salt concentrations. Given the same Na+ concentration, Na2CO3 inhibited seed germination and seedling growth more than NaCl. The results showed that the main factor affecting seed germination and seedling growth is not pH alone, but the interaction between pH and salt ions. Under NaCl stress, canola increased the absorption of K+, Ca2+, and Mg2+ in roots and K+ in leaves. However, under Na2CO3 stress, canola maintained a high K+ concentration and K+/Na+ ratio in leaves and increased Ca2+ and Mg2+ in roots. Our study showed that alkaline salts inhibit canola seed germination and seedling growth more significantly than neutral salts and salt species, salt concentration, and pH significantly affected on seed germination and seedling growth. However, pH affected seed germination and seedling growth mainly through an interaction with salt ions.

Na2CO3-responsive Photosynthetic and ROS Scavenging Mechanisms in Chloroplasts of Alkaligrass Revealed by Phosphoproteomics

Alkali-salinity exerts severe osmotic, ionic, and high-pH stresses to plants. To understand the alkali-salinity responsive mechanisms underlying photosynthetic modulation and reactive oxygen species (ROS) homeostasis, physiological and diverse quantitative proteomics analyses of alkaligrass (Puccinellia tenuiflora) under Na2CO3 stress were conducted. In addition, Western blot, real-time PCR, and transgenic techniques were applied to validate the proteomic results and test the functions of the Na2CO3-responsive proteins. A total of 104 and 102 Na2CO3-responsive proteins were identified in leaves and chloroplasts, respectively. In addition, 84 Na2CO3-responsive phosphoproteins were identified, including 56 new phosphorylation sites in 56 phosphoproteins from chloroplasts, which are crucial for the regulation of photosynthesis, ion transport, signal transduction, and energy homeostasis. A full-length PtFBA encoding an alkaligrass chloroplastic fructose-bisphosphate aldolase (FBA) was overexpressed in wild-type cells of cyanobacterium Synechocystis sp. Strain PCC 6803, leading to enhanced Na2CO3 tolerance. All these results indicate that thermal dissipation, state transition, cyclic electron transport, photorespiration, repair of photosystem (PS) II, PSI activity, and ROS homeostasis were altered in response to Na2CO3 stress, which help to improve our understanding of the Na2CO3-responsive mechanisms in halophytes.

Effects of Arbuscular Mycorrhiza Fungi on the Growth Characteristics, Root Morphology, and Ion Distribution of Pyrus betulaefolia Bunge under Saline-Alkaline Stress

Abstract In this study, Pyrus betulaefolia Bunge seedlings were used to investigate the effects of an arbuscular mycorrhiza fungus (AMF; Funneliformis mosseae) on plant-growth characteristics, root morphology, salt tolerance, and ion distribution under saline-alkaline stress. An indoor pot experiment was conducted in which seedlings were inoculated with Funneliformis mosseae under treatments of four different concentrations of Na2CO3 solution. The results show that AMF could establish symbiotic relations with the P. betulaefolia root system under Na2CO3 stress. Under the same Na2CO3 stress, AMF significantly increased the height growth and biomass accumulation of P. betulaefolia seedlings. AMF also promoted the root growth of P. betulaefolia seedlings. AMF inoculation significantly affected the absorption and distribution of K+ and Na+ in P. betulaefolia. The K/Na ratios in the roots and leaves of seedlings inoculated with AMF were higher than those of seedlings without inoculation. The results of this study show that inoculation with AMF had a positive effect on enhancing the saline-alkaline tolerance of P. betulaefolia, and root treatment of P. betulaefolia seedlings with Funneliformis mosseae has the potential for application in the development of saline-alkaline soil vegetation.

Fiber and seed type of hemp (Cannabis sativa L.) responded differently to salt-alkali stress in seedling growth and physiological indices

Hemp (Cannabis sativa L.) cultivars Yunma 5 (YM5, fiber-type) and Bamahuoma (BM, seed-type) were seriously affected by salt-alkali stress during germination, while the knowledge about the salt tolerance during seedling stage is deficient. Here, responses of hemp (Cannabis sativa L.) seedlings of the cultivars YM5 and BM to the stress of different concentrations of NaCl and Na2CO3 were investigated to explore the salt tolerance of hemp. Results showed that the plant height, dry weight and root length of YM5 and BM seedlings gradually decreased as the concentration of NaCl or Na2CO3 increased. Although physiological indices such as EC (Electrical conductivity), SOD (Superoxide dismutase) and Pro (Proline) increased as the salt concentration increased, the increase extent was significantly greater in YM5 than in BM. Under the conditions of 100 and 200 mM NaCl, BM had greater dry weight and root length, and lower Pro content than YM5. However, under the stress of 100 and 200 mM Na2CO3, the opposite results were recorded, with the exception for lower chlorophyll content and higher SOD activity in BM than in YM5. These findings indicated that BM had a stronger NaCl tolerance than YM5. Moreover, morphological indices of the two cultivars under Na2CO3 stress were stunted more than under NaCl stress, and the seedlings died when Na2CO3 concentration increased up to 300 mM. Some up-regulation of salt-tolerant genes were observed in the two hemp cultivars, a higher expression under NaCl stress than under Na2CO3 stress, and a higher expression in YM5 than in BM were recorded. Findings from the study indicated that hemp seedling is more sensitive to Na2CO3 stress, and the tolerance of hemp to salt stress varies with salt type and salt concentration, although both cultivars can withstand moderate doses of NaCl and Na2CO3.

Transcriptome Analysis of Gossypium hirsutum L. Reveals Different Mechanisms among NaCl, NaOH and Na2CO3 Stress Tolerance

As an important source of fiber and edible oil, cotton has great economic value. In comparison to their individual studies, association and differentiation between salt and alkaline tolerance has not been focused yet by scientists. We have used next-generation RNA-Seq technique to analyze transcriptional changes under salt and alkaline stresses in cotton. Overall, 25,929 and 6,564 differentially expressed genes (DEGs) were identified in roots and leaves, respectively. Gene functional annotation showed that genes involving ionic homeostasis were significantly up-regulated under NaCl stress and Na2CO3 stress, and genes enriched in starch and sucrose metabolism were up-regulated under NaOH stress and Na2CO3 stress. Furthermore, a synergistic enhancing effect between NaCl and NaOH stress was also observed in this study. Likewise, our studies indicate further that genes related with starch and sucrose metabolism were regulated to respond to the high pH under Na2CO3 stress, inducing plant hormone signal transduction and key enzyme reactive oxygen species (ROS) activity to respond to ionic toxicity and intracellular ionic homeostasis. By analyzing the expression profiles of diverse tissues under different salt and alkaline stresses, this study provides valuable ideas for genetic improvements of cotton tolerance to salt-alkaline stress.

Cloning and characterization of SucNHX1, a novel vacular Na+/H+ antiporter from the halophyte Suaeda corniculata that enhances the saline-alkali tolerance in Arabidopsis by its overexpression

Vacuolar Na+/H+ antiporters play central roles in plant saline (NaCl) stress response. However, the functional characterizations of antiporters involved in plant saline-alkali (Na2CO3/NaHCO3) tolerance are limited. In this study, SucNHX1, a Na+/H+ antiporter gene was isolated from Suaeda corniculata, a halophyte native to the saline-alkali soil, and further studied in transgenic Arabidopsis thaliana. The SucNHX1 gene contains 2123 nucleotides with an open reading frame of 1665 nucleotides (GenBank accession number: DQ512716), encoding a polypeptide of 554 amino acids with a predicted molecular mass of 61.2 kDa. A northern blot analysis indicated that the enhanced mRNA accumulation of SucNHX1 was induced by sodium carbonate (Na2CO3) rather than by NaCl, polyethylene glycol or abscisic acid in S. corniculata seedlings. SucNHX1 was localized in membrane, nucleus and cytoplasm when it was transiently expressed in tobacco mesophyll cells. The expression of SucNHX1 in salt sensitive yeast mutant ΔenaΔnhx1 which lost of yeast vacuolar Na+/H+ antiporter ScNHX1 showed functional complementation. The transgenic Arabidopsis overexpressing SucNHX1 had higher Na2CO3 and NaCl tolerance levels than the wild-type plants. The expression patern of SucNHX1 under Na2CO3 and high NaCl stress in transgenic plants showed that SucNHX1 higher expressed under stress condition than normal control. The analysis of ion contents indicated that under Na2CO3 and NaCl conditions, there were more Na+ in the roots and higher K+/Na+ ratio in the leaves in the transgenic plants than in the wild-type plants. Thus, SucNHX1 may play a significant role in plant saline-alkali tolerance.

Endophytic infection modifies organic acid and mineral element accumulation by rice under Na2CO3 stress

Saline and alkali soils severely impact plant growth. Endophyte and plant associations are known to significantly modify plant metabolism. This study reports the effects of a type of endophyte on organic acid (OA) accumulation and ionic balance in rice under Na2CO3 stress. Rice seedlings with (E+) and without (E-) endophytic infection were subjected to different levels of Na2CO3 stress (0, 5, 10, 15, and 20 mM) for two weeks. Organic acids and mineral elements in the leaves and roots were determined. Seedlings with endophytic infection accumulated mainly citrate and fumarate, with some malate and succinate in the leaves. In the roots, accumulation of malate and fumarate was enhanced significantly by endophytic infection, while less citrate and succinate was accumulated under Na2CO3 stress, which suggested that leaves and roots use different mechanisms to control OA metabolism. Endophytes reduced the total Na and Na:K ratios, but increased ST values, the percent changes of other measured nutrients, Chl content, and dry weight per plant under Na2CO3 stress. Endophytic infection plays a key role in maintaining plant growth by improving nutrient uptake and adjusting OA accumulation under Na2CO3 stress. The application of endophytes can enhance the resistance of rice to salinity.

Variation of rhizosphere environmental factors of sugarbeet seedlings under Na2CO3 stress and their correlation.

To study the effect of saline-alkali stress on dry mass, rhizosphere soil enzyme activities and soil microbial quantities, pot experiments were designed two sugar beet varieties, 'KWS0143' (strong tolerance to saline-alkali) and 'Beta464' (weak tolerance to saline-alkali) planted in different Na2CO3 concentrations [0% (control), 0.4%, 0.8% and 1.2% of soil], and the dry mass of seedlings,soil enzyme activities and amount of microbiology in soil were recorded. The results showed that compared with the control, the dry mass of seedlings was significantly increased in the treatment of 0.4% Na2CO3, while it was significantly decreased in the 0.8% and 1.2% Na2CO3 treatments. Significant differences among treatments were observed. The soil urease, alkali phosphatase and peroxidase activities in the root rhizosphere of seedlings presented a similar tendency under different concentrations of Na2CO3. Compared with the control, the enzyme activities with the treatment 0.4% Na2CO3 were not significantly enhanced, while those in the treatment of 0.8% and 1.2% Na2CO3 were significantly reduced. All the soil enzymes' activities in 'KWS0143 were higher than in 'Beta464'. The 0.4% Na2CO3 did not lead to significant change of soil microbial community, but 0.8% and 1.2% Na2CO3 sharply decreased the amount of soil bacteria, fungi and actinomycets (P<0.05). The amount of rhizosphere soil microbe in 'KWS0143' was higher than in 'Beta464'. There were significantly positive correlation among the dry mass, soil enzymes and soil microbe of the two varietie. Path coefficient analysis showed the determinant coefficient of 'KWS0143' dry mass was in order of sctinomycetes > bacteria > peroxidase > urease > fungi > alkali phosphatase, while that 'Beta464' dry mass was in order of actinomycetes > peroxidase > urease > fungi > alkali phosphatase > bacteria.

燕麦对松嫩草地三种主要盐分胁迫的生理适应策略

PDF HTML阅读 XML下载 导出引用 引用提醒 燕麦对松嫩草地三种主要盐分胁迫的生理适应策略 DOI: 10.5846/stxb201607111417 作者: 作者单位: 东北林业大学园林学院 哈尔滨,东北林业大学盐碱地生物资源环境研究中心,东北油田盐碱植被恢复与重建教育部重点实验室,白城师范学院,东北林业大学盐碱地生物资源环境研究中心,东北油田盐碱植被恢复与重建教育部重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（31502013）；黑龙江省自然科学基金资助项目（C2015060）；中央高校基本科研业务费专项资资助项目（2572015CA17） Physiologically adaptive strategies of oat seedlings to the three main salts in the soils of the Songnen Plains grasslands Author: Affiliation: Alkali Soil Natural Environmental Science Center,Northeast Forestry University/ Key Laboratory of Saline-alkali Vegetation Ecology Restoration in Oil Field,Ministry of education,Harbin,,,Geography Department of Baicheng Normal University,Baicheng Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为明确燕麦幼苗对松嫩盐碱草地3种主要盐分NaCl、NaHCO3和Na2CO3的适应机制，设定不同浓度梯度（48-144 mmol/L）的胁迫处理液，测定燕麦幼苗的生长与生理指标变化。结果表明，尽管试验设定的NaCl浓度并不影响幼苗的存活率，但在各组胁迫处理下，随着浓度的增加，燕麦幼苗的分蘖数、植株高度、茎叶与根系的生物量均呈下降趋势，下降幅度为Na2CO3 > NaHCO3 > NaCl。另外，与NaCl胁迫相比，Na2CO3与NaHCO3胁迫下茎叶与根中积累了更多的有毒Na+，同时K+下降幅度也更大，并且根系中含有更高的Na+与更低的K+以及更高的Na+/K+。在NaCl胁迫下，燕麦幼苗积累大量的无机Cl-和脯氨酸来维持细胞内的渗透与离子平衡，而NaHCO3与Na2CO3胁迫造成了燕麦幼苗体内阴离子的亏缺，此时幼苗主要通过积累大量的有机酸和更多的脯氨酸来维持渗透与离子平衡。上述结果表明，碱性盐Na2CO3与NaHCO3对植物的胁迫伤害程度大于中性盐NaCl，并且Na2CO3的毒害效应最强，而燕麦幼苗对不同的盐分胁迫伤害也有会产生不同的生理适应策略。 Abstract:To identify the coping mechanisms and the adaptive strategies of oat seedlings exposed to NaCl, NaHCO3, and Na2CO3, the main salts in the soils of the salt-alkali grasslands of the Songnen Plains of China, growth rates and physiological indices of oat seedlings were measured in plants grown in soils with different concentrations (48-144 mmol/L) of the three salts. The result demonstrated that although oat seedling survival rates were unaffected by NaCl stress, the tiller number, plant height, and shoot and root dry weights decreased with increasing salt concentration, in the order of Na2CO3 > NaHCO3 > NaCl. In addition, higher concentrations of Na+ accumulated in the shoots and roots of oat seedlings under Na2CO3 stress and NaHCO3 stress than in seedlings under NaCl stress. Reductions in concentrations of K+ were also greater under both Na2CO3 stress and NaHCO3 stress than under NaCl stress, especially in the roots. Large amounts of Cl- and proline were found to accumulate in oat seedlings, most likely as a strategy for maintaining osmotic and ionic homeostasis under NaCl stress, whereas substantially higher accumulations of proline and organic acid were observed to balance cation deficiency under Na2CO3 and NaHCO3 stresses. These results indicated that the stress effects on oat seedlings of Na2CO3 and NaHCO3 exposure were greater than that of NaCl exposure, with Na2CO3 stress having the strongest detrimental effect. In addition, oat seedlings responded to different levels of salt stress through the adoption of various physiological mechanisms. 参考文献 相似文献 引证文献

Effects of NaCl and Na2CO3 stresses on photosynthetic ability of Chlamydomonas reinhardtii

AbstractChloride and carbonate salts are the main salts causing salinization and widely exist in aquatic environment, so algae may suffer from salinization stress for high water evaporation. In this study, in order to investigate and compare the toxic effects of the two salts on algal photosynthesis, we used NaCl and Na2CO3 to stress Chlamydomonas reinhardtii. Under the two salt stresses, the content of O2−· and H2O2 in the cells was increased significantly, and it was much higher in Na2CO3 treatment than in NaCl treatment at the same Na+ concentration. The absorbance spectra and 4th derivative spectra of photosynthetic pigments were declined under 300 mM NaCl and 25 mM Na2CO3 stresses, and remarkably changed under 50 mM and 100 mM Na2CO3 stresses. When the cells stressed by the two salts, the maximum quantum yield (Fv/Fm), electron transport rate (ETR) and photochemical quenching (qP) were reduced markedly, but the nonphotochemical dissipation (NPQ) was increased markedly. At the same Na+ concentration, Na2CO3 stress had stronger toxic effects on photosynthetic ability than NaCl stress.

Effect of endophyte infection on chlorophyll a fluorescence in salinity stressed rice

We have earlier reported that the endophyte infection can enhance photosynthetic capacity and antioxidant enzyme activities in rice exposed to salinity stress. Now, the changes in primary photochemistry of photosystem (PS) II induced by Na2CO3 stress in endophyte-infected (E+) and endophyte-uninfected (E-) rice seedlings were studied using chlorophyll a fluorescence (OJIP-test). Performance indices (PIABS and PITotal) of E- and E+ rice seedlings revealed the inhibitory effects of Na2CO3 on PS II connectivity (occurrence of an L-band), oxygen evolving complex (occurrence of a K-band), and on the J step of the induction curves, associated with an inhibition of electron transport from plastoquinone A (QA) to plastoquinone B (QB). In E+ seedlings, Na2CO3 effects on L and K bands were much smaller, or even negligible, and also there was no pronounced effect on the J step. Furthermore, the OJIP parameters indicated that 20 mM Na2CO3 had a greater influence on the photosystem (PS) II electron transport chain than did the 10 mM Na2CO3, and that changes were greater in E- than in E+. Endophyte infection was therefore deemed to enhance the photosynthetic mechanism of Oryza sativa exposed to salinity stress.