Ionic Homeostasis and Expression of Na+ Related Genes of Cotton under Different Salt and Alkali Stresses

[Objective] Maintaining intracellular ion homeostasis is one of the important salt-tolerant mechanisms of crops. This study aims to analyze differences in response characteristics of cotton ionome and salt-tolerant gene expression under different saline-alkali stresses, which provides a basis for understanding the mechanism of salt tolerance and improving salt tolerance of cotton. [Method] Using Lumianyan 24 as the experimental material, three kinds of salt and alkali stress types (salt stress, alkali stress, and mixed salt-alkali stress) and two concentration gradients (low and high concentrations) were set under pot cultivation conditions. Meanwhile, non-saline-alkali stress treatment was set as control. The dry matter weight of cotton plants and root morphological parameters including root length, root surface area, and root volume were measured in this study. The concentrations of 13 elements such as P, Na, K, Ca and Mg in different organs of cotton plants were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The relative expressions of salt tolerance related genes GhDFR1, GhSOS1, GhNHX1 and GhAKT1 were determined by the quantitative real-time polymerase chain reaction method. [Result] 1) Salt and alkali stresses significantly inhibited cotton growth. The growth inhibition rate of cotton under mixed salt-alkali stress treatments (48.7%–57.9%) was significantly higher than that under salt stress (27.6%–49.9%) and alkali stress (21.2%–35.5%) treatments. Under salt stress and mixed salt-alkali stress treatments, both shoot and root growth of cotton were significantly inhibited, dry matter weight, root length, root surface area and root volume were significantly reduced, while root growth was less inhibited under alkali stress treatments. 2) Under three types of saline-alkali stresses, Na content and Mo content in different organs of cotton plant increased significantly, but N content in leaves and roots decreased. 3) Under salt stress treatments, the uptake of Ca, Mg, Fe, Mn and Zn in cotton was inhibited, and the ion balance was maintained by promoting the transport of these ions and P, K. 4) In addition to Ca, Mg, Fe, Mn and Zn, P uptake was also inhibited under alkali stress treatments, but K uptake and P, K, Ca, Mg, Fe, Mn and Zn transport were promoted. 5) Under mixed salt-alkali stress treatments, especially under high salinity and pH conditions, most of nutrients uptake was inhibited, and the transport capacity of Ca, Mg, Zn, Mn and Fe was reduced. 6) The relative expression of GhSOS1 and GhAKT1 genes increased significantly under salt stress treatments, but increased first and then decreased under alkali stress and mixed salt-alkali stress treatments. The relative expression levels of GhSOS1 and GhAKT1 genes under three types of saline-alkali stresses were alkali＞salt＞mixed saline-alkali stress. With the increase of soil salinity and pH value, the relative expression of GhNHX1 gene increased first and then decreased. The expression levels of GhNHX1 gene were salt＞alkali＞mixed salt-alkali stress. [Conclusion] Due to high salinity and pH value, mixed salt-alkali stress significantly inhibits cotton growth and ions uptake, which restricts the transport of P, K, Ca, Mg, Zn, Mn and Fe. The decrease of K and Na regulation ability leads to ions imbalance.     

谷子品种（系）萌发期耐盐碱性鉴定及评价

为鉴定谷子品种（系）的耐盐碱性,以24个谷子品种（系）为试验材料,设置0、40、80、120和160mmol/L5个盐碱梯度,通过对响应盐碱胁迫的8个主要指标进行多重比较、相关性分析、主成分分析、隶属函数分析、聚类分析、灰色关联度分析及回归分析等了解谷子萌发期对盐碱胁迫的响应并筛选出强耐盐碱性材料。结果表明,耐盐碱性谷子鉴定的最适宜盐碱浓度为80mmol/L。根据综合耐盐碱系数（CDC值）、耐盐碱性度量值（D值）及加权关联度（WDC值）对谷子耐盐碱性进行排序,其中耐盐碱性最强的5个品种（系）为泰谷004、豫谷18、龙谷25、冀谷168和K148。通过聚类分析将供试材料分为4类,分别包含9、10、3和2个品种（系）。灰色关联度及逐步回归分析表明,相对发芽势、相对发芽率、相对根长和相对芽长4个指标可以作为谷子品种耐盐碱性鉴定的综合指标。本研究为谷子盐碱机制的深入研究提供理论依据,为耐盐碱新品种的选育提供重要材料基础。     

Antioxidant and Photosynthetic Responses of Cotton to Soil Drought Stress during Flowering and Fruiting Stage

[Objective] The purpose of this study was to examine potential drought tolerance mechanisms in cotton (Gossypium hirsutum L.). Biochemical (antioxidant, protein and compatible osmolyte) and physiological (photosynthesis) responses to drought stress during the flowering and fruiting stages were examined. [Method] Using two cotton genotypes (A001 and A705) with different drought tolerance, a pot study was conducted in 2016 with treatments consisting of control (well-watered) and water stress. Water stress treatment was designed as withholding water from the pots until stomatal closure followed by limited water supply for 25 days where water-stressed plants received 40% of the optimum quantity of water. Measurements were made on soluble protein, proline and malonaldehyde (MDA) concentrations, peroxidase (POD) activity and photosynthetic characteristics (net photosynthetic rate P_n, transpiration rate E, stomatal conductance G_s) during the period of water stress. [Result] The soluble protein concentration was decreased and POD activity and MDA level were increased in the leaf subtending cotton boll of A001 under water deficit when compared with the control, but no response was observed in A705. Proline level responded to water deficit inconsistently between the two genotypes and across all sampling dates. Water stress significantly decreased P_n, E and G_s in the main stem leaves for both A001 and A705. [Conclusion] The results indicated that POD, soluble protein and MDA are involved in A001 and A705 responses to water deficit, and A705 is more tolerant to soil drought than A001.     

半野生棉与亚洲棉对草甘膦抗性评价及比较分析

采用叶片棉球定位鉴定法,初步鉴定并评价了半野生棉和亚洲棉对草甘膦的自然抗性,结果表明:参试材料抗性水平从高抗至高感分6级,极端抗性水平相差33.3倍(0.2%对0.006%)。其中,半野生棉对草甘膦的自然抗性分级丰富,抗性水平分布自高抗至高感;但大部分半野生棉不耐草甘膦,近86%(346份)的材料抗性水平处于低耐级别以下。而亚洲棉抗性水平都处于高抗至低耐的4个级别,抗性多样性较差,但整体抗性水平较高,70.3%(71份)表现为耐或以上级别。从半野生棉和亚洲棉中分别筛选到2份和5份高抗材料,半野生棉中有1份高感材料,亚洲棉中无对草甘膦敏感材料。本研究报道的极端材料为棉花草甘膦抗性遗传机制研究、新品种的培育、内源抗性基因的挖掘和感抗机理研究,奠定了良好的材料基础。     

Accession Variation for Salt Tolerance in Proso Millet (Panicum miliaceum L.) Using Leaf Proline Content and Activities of Some Key Antioxidant Enzymes

Inter‐accession variation for salt tolerance of Panicum miliaceum (proso millet) was appraised using leaf proline content and activities of antioxidant enzymes as selection criteria. Eighteen accessions of proso millet were grown under control conditions and after 14 days subjected to saline (120 mm NaCl) stress for 4 weeks. Salt stress substantially decreased relative water content (RWC), while increased leaf free proline and malondialdehyde (MDA) and activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of all accessions of proso millet. The difference among the accessions of P. miliaceum was significant in yield as well as in the activities of antioxidant enzymes analyses. On the basis of seed yield (expressed as per cent of control), of 18 accessions, three were categorised as salt‐tolerant (008211, 008214 and 008226), seven as moderately tolerant (008210, 008213, 008216, 008220, 008222, 008223 and 008242) and eight as salt‐sensitive (008208, 008215, 008217, 008218, 008221, 008225, 008230 and 008236). Of all P. miliaceum accessions, 008211, 008226, 008215 and 008218 were relatively higher in proline, 008214 and 008221 in MDA contents, 00812, 008225, 008236, 008222 and 008242 in SOD activity and 008218, 008220, 008211 and 008226 in POD and CAT enzyme activities. Thus, because of differential response of high or low seed yielded accessions in accumulation of proline and antioxidant enzyme activities, these variables were not found effective criteria for discriminating the P. miliaceum accessions for salt tolerance.     

陆地棉NAC转录因子基因GhNAC6的克隆、表达和耐盐性分析

【目的】NAC(NAM-ATAF-CUC)家族是植物细胞内特有的1类转录因子家族,参与植物的抗逆过程。为了研究棉花抗逆的分子机制,本研究从陆地棉TM-1中克隆到1个NAC转录因子基因并研究了其功能。【方法】根据其序列同源性和进化分析结果,将该基因命名为GhNAC6,本文对GhNAC6进行了生物信息学和表达分析,并利用病毒诱导基因沉默技术在棉花中沉默GhNAC6的表达。【结果】GhNAC6全长为1629 bp,包含2个内含子,其中编码区为900 bp,编码1个相对分子质量为33.9×10~3、等电点为6.18的蛋白。GhNAC6启动子区段包含多个与诱导表达和组织特异表达相关的顺式作用元件。转录组数据分析结果表明,GhNAC6在棉花发育的不同时期具有时空表达差异性;实时荧光定量核酸扩增检测结果显示GhNAC6还受到植物激素水杨酸、乙烯利、茉莉酸甲酯和逆境胁迫低温、高温、高盐、伤口的诱导。干涉GhNAC6基因发现,降低GhNAC6基因的表达能增强棉花对盐胁迫的耐受性。【结论】研究结果表明GhNAC6可能参与了棉花发育、逆境响应和激素信号传导的过程。     

盐胁迫下施钾调节棉纤维断裂比强度的糖代谢机制

【目的】研究盐胁迫下施钾调节棉花纤维断裂比强度的糖代谢机制,为盐碱地适量施钾提供理论依据。【方法】以中棉所79(耐盐型)和泗棉3号(盐敏感型)为试验材料,通过设置3个土壤电导率(低盐1.68~1.78 dS·m^-1、中盐6.21~6.42 dS·m^-1、高盐10.59~11.08 dS·m^-1),3个施钾量(0、150、300 kg·hm-2),研究了盐胁迫下施钾对棉花纤维断裂比强度、纤维加厚发育期纤维素累积和蔗糖、β-1,3-葡聚糖及相关酶活性的影响。【结果】(1)盐胁迫显著降低了棉花纤维断裂比强度;施钾显著缓解了中、高盐胁迫下盐分对纤维断裂比强度的影响,但施钾150、300 kg·hm^-2处理间无显著差异。盐碱地施钾,中棉所79的纤维断裂比强度增幅高于泗棉3号。(2)盐胁迫降低了纤维加厚期纤维素的累积量,降低了纤维蔗糖含量并提高了β-1,3-葡聚糖含量;盐碱地施钾则提高了纤维加厚发育期纤维素最大累积速率,提高了花后28 d磷酸蔗糖合成酶以及β-1,3-葡聚糖酶的活性,提高了蔗糖及β-1,3-葡聚糖含量,且施钾缓解作用随盐胁迫程度加重而逐渐减弱。施钾条件下,中棉所79的纤维素最大累积速率及β-1,3-葡聚糖酶活性的增幅高于泗棉3号。【结论】盐碱地适量施钾可缓解盐胁迫对棉花纤维断裂比强度的影响。     

100份谷子品种资源萌发期耐盐性评价及耐盐品种筛选

研究了100份谷子品种资源萌发期盐胁迫条件下芽、根的变化,并对供试材料的耐盐性进行了综合评价和等级划分,结果表明：150mmol/L的NaCl溶液是谷子萌发期耐盐筛选的最适浓度;盐胁迫条件下谷子芽受到的抑制作用小于根;100份谷子品种资源各测定指标变异系数由大到小顺序为：发芽相对盐害率>相对活力指数>相对发芽势>相对根干重>相对芽干重>相对发芽指数>相对芽长=相对根长>相对发芽率;晋育红谷、公矮6号、红钙谷和晋谷29共4个品种为综合耐盐能力强的资源。     

转GHABF4转录因子棉花植株的耐盐性研究

AREB/ABFs转录因子家族基因主要参与干旱、高盐、低温等胁迫应答反应。为了获得具有较高耐盐水平的棉花新种质材料,通过农杆菌介导法将耐盐转录因子基因(GHABF4)导入陆地棉中棉35中,通过对转化植株的卡那霉素初步筛选及T1、T2、T3目的基因PCR的分子检测,获得T3转基因棉花纯合系。通过盐胁迫试验对5个T3转基因棉花株系和非转基因棉花对照进行耐盐性分析。结果表明,在200 mmol/L Na Cl胁迫下,与非转基因对照相比,5个转基因棉花株系株高提高2.5~4.4 cm,地上部分的鲜质量增加3.6%~11.8%;且抗氧化物酶SOD、POD、CAT活性以及叶绿素含量提高。在盐胁迫条件下,转GHABF4基因棉花表现出优良的生长和生理优势,转GHABF4基因能够提高棉花的抗盐能力。     

Evaluation of the Low-Temperature Tolerance of Cotton Varieties in the Huang-Huai Region during Seed Germination

[Objective] To provide a theoretical foundation and germplasm resources for low-temperature-germination cotton breeding, the germination characteristics of 38 cotton varieties novel to or formerly widely planted in the Huang-Huai Region were evaluated under different low temperature stress conditions. [Method] Analysis of variance, the fuzzy membership function method, and cluster analysis were used to comprehensively evaluate the tolerance of these varieties to low temperature stress. [Result] As the temperature was lowered, germination rate, germination index, and vigor index exhibited a decreasing trend in all cotton varieties, but resistance to low temperature was significantly different among varieties. Cluster analysis divided the 38 varieties into three categories: highly resistant, resistant, and non-resistant. [Conclusion] Early-introduced varieties and those bred from early-introduced germplasm resources had weaker resistance to low temperature stress, with Stoneville and Deltapine series showing the lowest tolerance. The new transgenic insect-resistant cotton varieties SCRC 37 and SCRC 36 had the strongest resistance to low temperature stress.     

PAM施用深度对盐碱胁迫下藜麦生长及生理指标的影响

以陇藜4号为试验材料，采用根管土柱栽培试验，设置轻度(S1,3g/kg)、中度(S2,5g/kg)和重度盐碱胁迫(S3,7g/kg)以及土壤调理剂聚丙烯酰胺(PAM)施用深度0～10(PAM₀)、10～20(PAM₁₀)、20～30(PAM₂₀)和0～30cm(PAM₃₀)的完全随机试验组合，以土壤中不加盐碱和PAM为对照组(S0)，共计13个处理组合，研究PAM施用深度对不同盐碱胁迫条件下藜麦生长及生理指标的影响。结果表明，盐碱胁迫处理和PAM施用深度处理均会对藜麦的形态指标和生理指标造成显著影响：在合理施用PAM的前提下，与对照相比，轻度盐胁迫反而更有利于藜麦的生长，甚至中度盐胁迫下藜麦生长也没受到显著影响，表明藜麦具有较强的耐盐性。当盐碱胁迫达到重度(S3)时，虽然不同PAM施用浓度对藜麦生长有一定影响，但与对照相比，盐碱胁迫均显著抑制了藜麦地上部的生长；不同盐碱胁迫条件下不同PAM施用方式对藜麦生长及生理指标的影响均表现为PAM₀处理的效果最佳。隶属函数结果表明，不同处...     

Evaluation and QTL Mapping of Tolerance to Salinity Using Interspecific Introgression Lines from Gossypium barbadense in G. hirsutum

[Objective] Tolerance evaluation is the basis for cotton salinity-resistant breeding. [Method] Relative growth of cotton plants at seedling stage for 148 introgression lines was used to evaluate the tolerance to salinity. [Result] The results demonstrated that salt damage coefficients were significantly different from each other, with an average 61.22% ranging from 1.34% to 100%. Based on the salt damage coefficient, 148 introgression lines were divided into three groups; group 1 (23.65%) was more tolerant than the tolerant parent with the salt damage coefficient less than 29.35%; group 2 (39.19%) was more sensitive than the tolerant parent with the salt damage coefficient from 29.35%―71.70%; group 3 (37.16%) was more sensitive than the susceptible parent with the salt damage coefficient above 71.70%. [Condusion] Mapping of QTLs (Quantitative trait locus) for salt-tolerant traits indicated that 23 QTLs for tolerance-related traits were detected. Among them, 12 QTLs were aggregately distributed on chromosomes A05, A12, D05 and D11. Our results demonstrate that it is feasible for screening salt-tolerant introgression lines from Gossypium barbadense into G. hirsutum, especially by molecular marker-assisted selection for specific chromosomes with high efficiency.     

Differences in Ion Accumulation and Salt Tolerance among Glycine Accessions

Salinity reduces crop yield by limiting water uptake and causing ion‐specific stress. Soybean [Glycine max (L.) Merr.] is sensitive to soil salinity. However, there is variability among soybean genotypes and wild relatives for salt tolerance, suggesting that genetic improvement may be possible. The objective of this study was to identify differences in salt tolerance based on ion accumulation in leaves, stems and roots among accessions of four Glycine species. Four NaCl treatments, 0, 50, 75 and 100 mm , were imposed on G. max, G. soja, G. tomentella and G. argyrea accessions with different levels of salinity tolerance. Tolerant genotypes had less leaf scorch and a greater capacity to prevent Na⁺ and Cl^? transport from soil solution to stems and leaves than sensitive genotypes. Magnitude of leaf injury per unit increase in leaf Na⁺ or Cl^? concentrations was lower in tolerant than in susceptible accessions. Also, plant injury was associated more with Na⁺ rather than with Cl^? concentration in leaves. Salt‐tolerant accessions had greater leaf chlorophyll‐meter readings than sensitive genotypes at all NaCl concentrations. Glycine argyrea and G. tomentella accessions possessed higher salt tolerance than G. soja and G. max genotypes.     

Variation in Salinity Tolerance in Sunflower (Helianthus annum L.)

Forty-five accessions of sunflower collected from different countries were screened for salinity tolerance after 2 weeks growth in sand culture salinized with 150 meq l^?1 of NaCl₂+ CaCl₂ (1:1 ratio equivalent wt. basis) in half strength Hoagland's nutrient solution. The results for plant biomass of 45 accessions show that there was considerable variation in salinity tolerance. In a further greenhouse experiment, the salinity tolerance of three tolerant (HO-1, Predovik, Euroflor) and two sensitive (SMH-24, 9UO-985) lines (selected on the basis of their performance in the seedling experiment) was assessed at the adult stage to evaluate the consistency of salinity tolerance at different growth stages. All three salt tolerant accessions produced significantly greater plant biomass, seed yield and seed oil content than the salt sensitive accessions. The tolerant accessions accumulated less Cl^? and more K⁺ in the leaves under saline conditions compared with the salt sensitive accessions. The salt tolerant accessions also maintained relatively high leaf K:Na ratio and K⁺ versus Na⁺ selectivity. Although statistically nonsignificant, all three tolerant accessions had greater soluble carbohydrates, soluble proteins, total free amino acids and proline in the leaves than the sensitive accessions. A field trial conducted in a salt-affected field confirmed the greenhouse results of the selected accessions. This study shows that salinity tolerance of sunflower does not vary with stage of plant cycle, so selection for increased salt tolerance can be carried out at the initial growth stage. Secondly, it is found that there is great variation of salt tolerance in sunflower. Low uptake of Cl^?, high uptake of K⁺, and maintenance of high K:Na ratios and K⁺ versus Na⁺ selectivity in the leaves and possibly the accumulation of organic osmotica such as soluble carbohydrates, soluble proteins, proline and free amino acids seem to be the important components of salt tolerance in sunflower.     

绒毛白蜡耐盐碱响应机制的研究进展

文章主要叙述了盐碱胁迫对绒毛白蜡种子萌发、形态及生长、光合速率、叶绿素含量和细胞膜透性的影响,阐述了绒毛白蜡在盐胁迫下产生的表型上的适应性、渗透调节物质的合成、离子的转运和区域化、保护酶的生成等形态和生理响应机制,概述了绒毛白蜡耐盐碱分子响应机制的研究进展,包括差异基因表达和关键基因分析以及表观遗传调控机制。研究认为,应加强对绒毛白蜡在盐碱胁迫、干旱胁迫等多种胁迫共同发生时响应机制的研究,为更好地筛选和培育耐盐碱乔木树种提供实验依据。     

滨海盐碱地转基因抗虫棉品种鉴选

为探明转基因抗虫棉的耐盐性，筛选出适合盐碱地种植的抗虫棉高产品种，不同盐分含量砂培试验与滨海盐碱地大田试验相结合。研究了不同基因型抗虫棉的耐盐性及其生育特点和产量表现。结果表明。供试抗虫棉品种间的耐盐性存在差异，但耐盐程度皆十分有限。从不同基因型抗虫棉的耐盐性、出苗成苗率、生长情况和产量等分析。以鲁棉研17、鲁棉研21、鲁536、中棉所45和鲁棉研18综合性状较好，适宜于盐碱地种植，可作为当前盐碱地植棉的适宜品种。     

大豆根区逆境耐性的种质鉴定及其与根系性状的关系

依根系类型从黄淮海和长江中下游地区301份代表性材料中选取62份，以株高、叶龄、地上部干物重、地下部干物重为指标，采用平均隶属函数值方法鉴定了苗期耐旱性、苗期耐铝毒性，加上主茎节数、分枝数、单株荚数、单株粒数、百粒重等性状鉴定了后期耐旱性，并通过钒钼黄比色法测定植株P含量鉴定了苗期耐低磷性。筛选出1级苗期