土壤盐渍化是影响大豆生长的重要非生物胁迫之一。评价与筛选耐盐性大豆种质资源对于挖掘耐盐碱基因、耐盐大豆品种选育及盐碱地高效利用具有重要意义。本研究以50份大豆种质资源为研究对象, 进行了发芽期(0.6% NaCl)、苗期(1.5% NaCl)和全生育期(0.9% NaCl)的耐盐性鉴定, 基于芽期发芽率、苗期株高、叶面积、SPAD值、地上及地下部分的鲜重和干重及丙二醛含量等10个指标和全生育期株高、底荚高度、有效分枝、单株荚数、单株粒数、单株粒重等8个指标, 采用相关性分析、主成分分析、隶属函数法和聚类分析, 对大豆种质耐盐性进行综合评价, 并采用逐步回归分析建立了苗期和全生育期耐盐性预测回归模型, 明确了各时期的耐盐评价指标。结果表明, 依据盐害指数筛选出发芽期高耐盐种质8份, 耐盐种质10份, 高度盐敏感种质6份。利用主成分分析和隶属函数进行综合评价, 鉴定出苗期耐盐材料12份; 通过聚类分析方法将50份全生育期大豆材料分成5类: 高耐盐种质3份、耐盐种质3份、中等耐盐种质20份、盐敏感种质19份和高敏感种质5份。通过逐步回归分析, 建立大豆苗期耐盐性评价预测模型: D= -0.223 + 0.085X1 + 0.203X2 + 0.075X3 + 0.149X6 + 0.132X7 + 0.070X9 + 0.084X10 (R² = 0.969, P < 0.01)。筛选出相对株高、相对叶面积、相对SPAD、相对地下部分鲜重、相对地下部分干重、相对SOD活性、相对PRO含量可作为大豆苗期耐盐性鉴定的指标。建立大豆全生育期耐盐性评价预测模型: D= -0.153 + 0.143X1 + 0.443X6 + 0.171X7 (R² = 0.962, P < 0.01), 筛选出相对株高、相对单株粒数、相对单株粒重可以作为大豆全生育期耐盐性评价指标。本研究建立了一套全面精简、针对于大豆不同生育时期的耐盐性鉴定评价方法, 为大豆耐盐机理研究和耐盐新种质选育提供了技术体系和基础材料。

Understanding, predicting, and managing the impacts of human‐caused climate change will require long‐term monitoring of ecological changes across spatial scales. Although the National Ecological Observatory Network (NEON) aims to provide the backbone for such monitoring efforts in the US, regional climate changes that were observed before and that are projected to occur after NEON's implementation must be quantified. We use historical datasets and climate model projections to assess the rates, spatial patterns, and hotspots of temperature and precipitation change across NEON ecoregions. Hotspots with the highest elevated temperatures occur in the Tundra and Taiga ecoregions (absolute increases) as well as in the Pacific Southwest ecoregion (increases as compared with current variability). The observed and projected changes in temperature and precipitation can inform future NEON monitoring and research efforts in a rapidly changing climate.

When under salt stress, plants maintain a high concentration of K(+) and a low concentration of Na(+) in the cytosol. They do this by regulating the expression and activity of K(+) and Na(+) transporters and of H(+) pumps that generate the driving force for transport. Although salt-stress sensors remain elusive, some of the intermediary signaling components have been identified. Evidence suggests that a protein kinase complex consisting of the myristoylated calcium-binding protein SOS3 and the serine/threonine protein kinase SOS2 is activated by a salt-stress-elicited calcium signal. The protein kinase complex then phosphorylates and activates various ion transporters, such as the plasma membrane Na(+)/H(+) antiporter SOS1.

为明确不同燕麦材料苗期耐盐能力强弱和筛选出优异的燕麦种质,以前期试验筛选出的5份耐盐性较好的燕麦为材料,采用营养液沙培法,对3周龄幼苗进行0.9%NaCl连续处理7 d后,研究盐胁迫对供试燕麦幼苗生长特性、光合特性、叶绿素荧光参数、抗氧化酶活性、丙二醛含量和渗透调节物质含量等的影响,并通过主成分分析法和隶属函数法对5份燕麦苗期进行耐盐性综合评价。结果表明,盐胁迫下,供试材料各指标间差异显著(P<0.05)。青永久195相对白燕7号、青永久30、陇燕5号、陇燕4号有着较大的根表面积、根体积、较高的K⁺含量,较低的MDA含量,较高的P_n、qP、叶绿素含量以及POD活性;而青永久30的SOD、CAT活性大于其余材料;通过主成分分析筛选出无机渗透调节物质、膜脂过氧化性、抗氧化酶活性可作为燕麦苗期耐盐性评价的综合鉴定指标,根据耐盐综合评价值(D)得出材料耐盐性排序为青永久195>白燕7号>青永久30>陇燕5号>陇燕4号。

蚕豆(Vicia faba)耐盐碱性种质鉴定为挖掘耐盐碱基因和选育耐盐碱品种奠定基础, 对盐碱地利用具有重要意义。利用8 g∙L^-1混合盐碱溶液(NaCl、Na₂CO₃和Na₂SO₄, 质量比为9:1:1, pH9.25)对399份国内外蚕豆种质在萌发期进行胁迫处理, 并测定了3个发芽指标和13个根系指标, 采用相关性、主成分、隶属函数和系统聚类分析, 对各种质的耐盐碱性进行综合评价。结果表明: (1) 在盐碱胁迫下, 根系交叠数受到的影响最大, 关节点次之, 而根平均直径较稳定; (2) 交叠数与总连接点数之间, 分叉数与交叠数、总连接点数之间等大部分指标间均呈极显著正相关(P<0.01); 而根平均直径与根总数量、根尖数量、根总长、端点数、关节点数、连接数、分叉数、交叠数和总连接点数之间呈极显著负相关(P<0.01); (3) 根总表面积、根总投影面积、根总长和根总体积可作为蚕豆萌发期耐盐碱性鉴定的适宜指标; (4) 筛选出2份耐碱盐种质H0000809和H0000653, 2份盐碱敏感种质H0001714和H0002622; (5) 399份蚕豆种质可分为4类, 第I类为耐盐碱种质, 占0.75%; 第II类为中耐盐碱种质, 占8%; 第III类为弱耐盐碱种质, 占52.88%; 第IV类为不耐盐碱种质, 占38.35%。综上, 该研究明确了各指标的变异程度和相关性, 确定了耐盐碱性鉴定的关键指标, 筛选出的极端材料可用于蚕豆耐盐碱机理研究和耐盐碱基因挖掘。

为挖掘燕麦（Avena sativa L.）耐盐基因，筛选耐盐品种，本研究利用水培法，采用0，100，200，250，300 mmol&middot;L^-1 NaCl对&lsquo;VAO-9&rsquo;与&lsquo;蒙农大燕1号&rsquo;两个燕麦品种幼苗进行盐胁迫处理，研究72 h内叶片质膜系统、渗透调节物质和抗氧化物酶活性变化，根据生理指标的变化判断幼苗生理响应机制。结果表明，燕麦在盐胁迫下通过调动自身渗透调节物质，维持生物膜的稳定性，提高抗氧化物酶系统的酶活性，抵御一定的盐胁迫。

为了探讨&lsquo;定莜6号&rsquo;燕麦对盐胁迫的生理生化响应及H₂O₂的调节作用，采用水培方法，研究外源H₂O₂对盐胁迫下燕麦活性氧代谢、渗透溶质积累和Na⁺、K⁺平衡的影响。结果表明：小于100 mmol&middot;L^-1 NaCl未对&lsquo;定莜6号&rsquo;幼苗的生长造成明显影响，150 mmol&middot;L^-1及以上浓度NaCl使幼苗干重和叶片K⁺/Na⁺显著降低，O₂^-_&middot;产生速率、H₂O₂、丙二醛（MDA）、可溶性蛋白质和脯氨酸含量及过氧化氢酶（CAT）、质膜H⁺-ATP酶活性明显提高，但抗坏血酸（ASA）和谷胱甘肽（GSH）含量变化不大；外施5 &mu;mol&middot;L^-1 H₂O₂可显著缓解150 mmol&middot;L^-1 NaCl胁迫对燕麦幼苗生长的抑制作用，使燕麦叶片超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）和CAT活性及H₂O₂、GSH含量明显提高，O₂^-_&middot;产生速率和MDA含量显著降低；5 &mu;mol&middot;L^-1 H₂O₂还提高了150 mmol&middot;L^-1 NaCl胁迫下燕麦叶片可溶性蛋白质、可溶性糖、有机酸和脯氨酸含量及质膜H⁺-ATP酶活性和K⁺/Na⁺，降低了游离氨基酸含量；表明外源H₂O₂可调控燕麦幼苗活性氧代谢和渗透溶质积累，维持K⁺、Na⁺平衡，从而增强耐盐性。

为研究4份燕麦坝莜一号、白燕2号、白燕6号和白燕7号的耐盐程度及其在盐胁迫处理下的生理反应规律,在水培条件下,分别用0,34.2,68.4,102.6,136.8,171.0 mmol/L浓度NaCl溶液模拟盐胁迫处理4种燕麦种子,观察记录各处理的盐害情况,分别测定了胁迫后的种子发芽势、发芽率、株高和根长,以及室温培养的燕麦幼苗叶片过氧化物酶(POD)、超氧化物歧化酶(SOD)和可溶性蛋白含量,分析了不同胁迫程度下各生理指标的变化情况,并且对4种燕麦的耐盐性进行了综合评价。结果表明,NaCl胁迫对4种燕麦种子的发芽势和发芽率均产生显著影响,对株高和根长产生了抑制作用,且均随盐浓度的增大呈逐渐降低的趋势;燕麦幼苗叶片POD活性、SOD活性、可溶性蛋白含量均在102.6 mmol/L 盐浓度下达到最大值,而且都随盐浓度的增大呈先升高后降低的趋势,表明燕麦具有较高的耐盐能力,在盐胁迫下可采取自我保护机制以适应盐胁迫,4种燕麦的耐盐阈值为102.6 mmol/L盐浓度。综合评价,白燕6号耐盐性较好,白燕2号具有高盐耐受性的潜力,这两个燕麦品种可以为耐盐基因挖掘及燕麦耐盐品种的选育提供材料。

针对西北盐碱地区栽培土壤资源有限问题，研究混合盐碱胁迫对醉马草种子萌发及幼苗生理相关酶特性的影响，旨在探讨与揭示醉马草对盐碱土壤环境的适应机制，为西北盐碱地区的耐盐草种的选育及栽培提供理论基础。为模拟西北地区复杂的盐碱环境，本研究将中性盐（NaCl、Na₂SO₄）和碱性盐（NaHCO₃、Na₂CO₃）按不同比例混合（A： NaCl∶Na₂SO₄=1∶1； B： NaCl∶Na₂SO₄∶ NaHCO₃=1∶2∶1； C： NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=1∶9∶9∶1； D： NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=1∶1∶1∶1； E： NaCl∶Na₂SO₄∶NaHCO₃∶Na₂CO₃=9∶1∶1∶9），并设置50、100、150、200 mmol·L^-14个盐浓度梯度对带菌（E+）和不带菌（E-）醉马草种子萌发和幼苗生长阶段进行胁迫，分析盐胁迫下醉马草种子萌发阶段的发芽率、发芽势、发芽指数、活力指数、平均发芽时间及幼苗生长阶段的苗长、胚根长度、根冠比、抗氧化酶（POD、SOD、CAT）活性、丙二醛 （MDA）和脯氨酸（proline）含量。并通过隶属函数和主成分分析对不同盐胁迫下的醉马草耐盐性进行综合评价。结果表明：5种盐碱胁迫均使醉马草发芽率、发芽势、发芽指数、活力指数降低及平均发芽时间延长，且随盐浓度的增加，种子萌发受到显著抑制（P<0.05）；盐碱胁迫亦随盐浓度的增加使醉马草胚根长度、根冠比显著降低。除C、E处理外，其余混合盐碱胁迫下的醉马草幼苗生理指标（POD、SOD、MDA、proline）均随盐浓度的上升而下降。隶属函数和主成分分析显示不同混合盐碱胁迫下的醉马草耐盐性大小顺序为A>D>B>C>E。综上可知，盐碱胁迫显著抑制醉马草种子萌发和幼苗生长（P<0.05），其中碱性盐（NaHCO₃、Na₂CO₃），尤以Na₂CO₃对醉马草种子萌发和幼苗生长抑制作用强于中性盐。活力指数、胚根长度、POD、SOD、proline为评价醉马草耐盐性的主要指标。E+醉马草耐盐性优于E-，内生真菌可有效提高醉马草渗透调节和活性氧清除能力，降低膜脂过氧化作用，提高醉马草耐盐性。

Salinity stress is a major constraint to sustainable crop production due to its adverse impact on crop growth, physiology, and productivity. As potato is the fourth most important staple food crop, enhancing its productivity is necessary to ensure food security for the ever-increasing population. Identification and cultivation of salt-tolerant potato genotypes are imperative mitigating strategies to cope with stress conditions. For this purpose, fifty-three varieties of potato were screened under control and salt stress conditions for growth and yield-related traits during 2020. Salt stress caused a mean reduction of 14.49%, 8.88%, and 38.75% in plant height, stem numbers, and tuber yield, respectively in comparison to control. Based on percent yield reduction, the genotypes were classified as salt-tolerant (seven genotypes), moderately tolerant (thirty-seven genotypes), and salt-sensitive genotypes (nine genotypes). Seven salt-tolerant and nine salt-sensitive genotypes were further evaluated to study their responses to salinity on targeted physiological, biochemical, and ionic traits during 2021. Salt stress significantly reduced the relative water content (RWC), membrane stability index (MSI), photosynthesis rate (Pn), transpiration rate (E), stomatal conductance, and K+/Na+ ratio in all the sixteen genotypes; however, this reduction was more pronounced in salt-sensitive genotypes compared to salt-tolerant ones. The better performance of salt-tolerant genotypes under salt stress was due to the strong antioxidant defense system as evidenced by greater activity of super oxide dismutase (SOD), peroxidase (POX), catalase (CAT), and ascorbate peroxidase (APX) and better osmotic adjustment (accumulation of proline). The stepwise regression approach identified plant height, stem numbers, relative water content, proline content, H2O2, POX, tuber K+/Na+, and membrane stability index as predominant traits for tuber yield, suggesting their significant role in alleviating salt stress. The identified salt-tolerant genotypes could be used in hybridization programs for the development of new high-yielding and salt-tolerant breeding lines. Further, these genotypes can be used to understand the genetic and molecular mechanism of salt tolerance in potato.

The modulation of antioxidant components was comparatively analysed in a salt‐tolerant (cv. Prasad) and salt‐sensitive (cv. Lepakshi) cultivar of foxtail millet (Setaria italica L.) under different NaCl concentrations. Under conditions of salt stress, the salt‐tolerant cultivar exhibited increased total superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity, whereas both enzyme activities decreased in acutely salt‐stressed seedlings of the sensitive cultivar. At 200 mM NaCl, the tolerant foxtail millet cultivar responded with induction of cytosolic Cu/Zn‐SOD and the Mn‐SOD isoform at the protein level. The induced accumulation of the cytosolic Cu/Zn‐SOD protein/activity is positively correlated with an elevated level of the cytosolic APX gene activity. The elevated cytosolic Cu/Zn‐SOD and cytosolic APX activity correlates with an induced accumulation of their transcripts. Tolerant 5‐day‐old seedlings grown during high salinity treatment (200 mM NaCl) contained a lower amount of Na+ ions and showed a lower electrolyte leakage than sensitive seedlings. In conclusion, our comparative studies indicate that salt‐induced oxidative tolerance is conferred by an enhanced compartment‐specific activity of the antioxidant enzymes in response to compartment‐specific signals.

The discovery of motifs in biosequences is frequently torn between the rigidity of the model on one hand and the abundance of candidates on the other hand. In particular, motifs that include wild cards or "don't cares" escalate exponentially with their number, and this gets only worse if a don't care is allowed to stretch up to some prescribed maximum length. In this paper, a notion of extensible motif in a sequence is introduced and studied, which tightly combines the structure of the motif pattern, as described by its syntactic specification, with the statistical measure of its occurrence count. It is shown that a combination of appropriate saturation conditions and the monotonicity of probabilistic scores over regions of constant frequency afford us significant parsimony in the generation and testing of candidate overrepresented motifs. A suite of software programs called Varun is described, implementing the discovery of extensible motifs of the type considered. The merits of the method are then documented by results obtained in a variety of experiments primarily targeting protein sequence families. Of equal importance seems the fact that the sets of all surprising motifs returned in each experiment are extracted faster and come in much more manageable sizes than would be obtained in the absence of saturation constraints.