外源硝态氮对高铵胁迫下小麦幼苗生长的影响

为明确外源硝态氮对高铵胁迫下小麦幼苗生长的影响及其生化机理,采用温室水培的方式,以豫麦49(耐高铵品种)和鲁麦15(高铵敏感型品种)为材料,研究了外源硝态氮对高铵胁迫下小麦幼苗形态、激素含量和抗氧化系统的影响。结果表明,高铵胁迫条件下,外源硝态氮显著增加两个小麦品种株高、根长、干重,其中鲁麦15的地上部干重增加量高于豫麦49,而根系干重增加量则表现为豫麦49高于鲁麦15。高铵胁迫下,两个小麦品种植株的IAA、CTK含量、IAA/CTK显著低于对照;外源硝态氮处理5 d后,豫麦49地上部和根系IAA含量、根系CTK含量显著增加,恢复至对照水平;鲁麦15植株虽亦表现显著增加,但仍低于对照。另外,外源硝态氮对高铵胁迫下两个小麦品种地上部和根系的O■释放速率、SOD和POD活性及MDA含量没有显著影响。综上,外源硝态氮缓解小麦幼苗生长高铵胁迫的原因可能是通过增加IAA和CTK合成和转运,影响IAA和CTK之间的平衡,进而达到缓解效果。品种间比较,耐铵型品种豫麦49缓解作用可能源于对地上部和根系IAA含量以及根系CTK含量的协同调控;而高铵敏感型品种鲁麦15的缓解作用可能主要源于对地上部IAA含量的调控。     

不同小麦品种苗期抗氧化特性及根系活力对盐胁迫的响应

为探讨不同耐盐性小麦品种苗期的生理差异,以小麦品种济麦22、青麦6号、德抗961、青丰1号为材料,在Hoagland营养液培养条件下,分析了NaCl胁迫对小麦幼苗叶片抗氧化酶活性、渗透调节物质含量及根系活力的影响。结果表明,随盐浓度及胁迫时间的增加,叶片SOD活性、可溶性蛋白含量不同程度地减小;POD活性及根系活力呈先增后减趋势,且均在胁迫1 d时出现最大值;MDA含量、游离脯氨酸含量不同程度地升高。品种间6个指标因盐胁迫浓度及胁迫天数的不同表现出不同的差异性,其中根系活力对于品种耐盐性有较强的鉴定价值;耐盐性高的青麦6号、德抗961各指标均显著高于耐盐性弱的济麦22和青丰1号。     

抗坏血酸对盐胁迫下小麦幼苗生长抑制的缓解效应

为探明抗坏血酸(AsA)对盐胁迫下小麦幼苗生长的调控作用,采用室内水培法研究了不同浓度AsA处理对0.1 mmol·L-1 NaCl胁迫下2个小麦品种(周麦9号和周麦23号)幼苗生长的影响.结果表明,外施AsA极显著提高了盐胁迫下小麦幼苗的根长、芽长,幼苗叶片的Pro和可溶性蛋白含量以及根系活力显著升高,细胞膜透性及膜脂过氧化产物MDA含量显著降低.2个小麦品种对AsA处理的敏感程度存在差异,ASA对周麦23号的缓解效果相对较好.本实验中以1.5 mmol·L-1外源AsA缓解效果最好.     

低温对小麦幼苗干物质积累及根系分泌物的影响

为了解小麦干物质积累和根系分泌物变化与小麦抗寒性的关系,采用盆栽方法,以弱春性小麦品种兰考矮早八、偃展4110和半冬性小麦品种豫麦49-198、周麦18为材料,设置4个不同温度处理(T1:昼夜均为18℃;T2:昼夜分别为12℃/7℃;T3:昼夜均为4℃;T4:昼夜均为-10±3℃),研究了低温对小麦幼苗干物质积累、根系分泌物和相对电导率的影响。结果表明,低温胁迫2 d,小麦根系分泌物中可溶性蛋白、可溶性糖及总酚含量升高;低温胁迫3 d,T3处理下,小麦根系分泌物中游离氨基酸和总酚含量较高,T4处理下小麦根系分泌物中可溶性蛋白、游离氨基酸及总酚含量均表现最低,而可溶性糖含量较高。低温胁迫下,根系相对电导率升高,其中豫麦49-198升幅最小,而兰考矮早八升幅最大。低温胁迫下,小麦幼苗干物质积累受到抑制。T3处理下,豫麦49-198干物质积累及幼苗相对生长速率均较高。在4个小麦品种中,豫麦49-198抗寒性较强,兰考矮早八抗寒性较弱。     

小麦干热风抗性鉴定及热胁迫相关基因TaHSPs的表达分析

为鉴定黄淮麦区小麦品种干热风抗性以及不同抗性品种热激蛋白(TaHSPs)基因的表达差异,以98个小麦品种为试验材料,于花后10~20d进行人工模拟干热风处理,通过测定小麦不同生长时期的叶绿素含量、收获后的千粒重与籽粒品质,评价不同品种干热风抗性;对筛选出的干热风抗性不同的品种在出苗15d进行热胁迫处理,通过荧光定量PCR测定热胁迫0~4.5h内TaHSPs基因表达量的变化。结果表明,干热风处理后,供试小麦品种旗叶的叶绿素含量均降低,高抗干热风品种降幅较小,热敏感型品种降幅较大;供试小麦品种的千粒重均降低。山农23号等3个品种达到高、中抗干热风等级,且抗性比较稳定,师栾02-1为热敏感型品种。干热风处理后籽粒蛋白质含量升高,总淀粉含量降低,抗干热风小麦品种总淀粉相对含量降幅较小。不同小麦品种幼苗在热胁迫0~4.5h期间,TaHSPs基因表达量均为抛物线趋势,抗干热风品种在热胁迫1h时TaHSP16.9基因表达上调幅度大于热敏感型品种。对于TaHSP17.8基因,抗干热风品种在热胁迫期间,上调表达反应时间均早于热敏感型品种;在热胁迫0.5h时,山农23号、周麦18与泰山9818三个抗干热风品种基因表达均上调至590倍以上,而师栾02-1与济南17号的上调幅度在300倍以下。对于TaHSP23.6基因,山农23号的上调表达峰值远高于其他品种。对于TaHSP26.6基因,热敏感型品种在热胁迫后期的上调倍数高于抗干热风品种,师栾02-1与济南17号两个热敏感型品种在热胁迫4.5h时上调幅度均在4 000倍以上,而抗干热风品种山农23号、周麦18与泰山9818上调幅度均在3 000倍以下。     

盐胁迫下钾吸收途径的抑制对小麦叶片K~+、Na~+含量的影响

为研究盐胁迫下小麦维持钾、钠平衡的生理机制,以耐盐小麦沧麦6005和盐敏感小麦矮抗58为材料,利用TEA、NEM、Ba(NO_3)_2三种药物分别抑制钾离子通道、钾载体及非选择性阳离子通道,测定正常及盐胁迫下小麦叶片K~+、Na~+含量,比较耐盐性不同的小麦品种在K~+、Na~+吸收中的差异。结果显示,盐胁迫下,沧麦6005和矮抗58叶片K~+含量下降,Na~+含量增加;沧麦6005叶片Na~+含量低于矮抗58,K~+/Na~+比值高于矮抗58。正常条件下,NEM、TEA处理均可降低沧麦6005和矮抗58叶片K~+含量,NEM处理较TEA处理效果更为明显;TEA处理显著降低了盐胁迫下矮抗58叶片K~+含量,而NEM处理则明显降低了盐胁迫下沧麦6005的叶片K~+含量;TEA、NEM、Ba(NO_3)_2处理降低了盐胁迫下矮抗58叶片Na~+含量,仅NEM处理降低了沧麦6005叶片Na~+含量。综上所述,正常条件下,钾载体是小麦K~+吸收的主要方式;盐胁迫下,耐盐品种和盐敏感品种K~+吸收途径不同,耐盐品种的NSCCs和钾离子通道具有更强的"拒钠"能力。     

金禾9123等小麦品种的对比试验

为更好地服务三农,给生产上推荐优秀、高产、广适的小麦品种,以金禾9123、AK58、周麦16、周麦18、周麦22、济麦22、漯麦9号、郑育麦9987等8个品种做大区对比试验。现将试验观察结果汇报如下,供各地在小麦生产用种时参考。     

PEG胁迫对不同小麦品种幼苗抗旱生理指标的影响

为给小麦抗旱育种的早期筛选工作提供理论依据,以济麦262(抗旱型)、烟农19(中间型)和临麦2号(水分敏感型)为材料,采用PEG模拟干旱胁迫,探究干旱胁迫对不同小麦品种幼苗生物量、含水量、根系形态特征、抗氧化酶活性和叶绿素荧光参数的影响。结果表明,PEG胁迫下,三个品种中济麦262的生物量最大,地下部含水量显著高于临麦2号和烟农19;其根系的总长、总投影面积、总面积和总体积最大,且受抑制程度最低;其抗氧化酶活性在一定程度上明显增强,尤其是叶片和根系过氧化物酶、根系超氧化物歧化酶及叶片过氧化氢酶活性增强幅度显著高于临麦2号和烟农19;其叶片光化学荧光淬灭系数(qP)和PSⅡ的实际光化学效率与CK相比均呈下降的趋势,其中qP下降程度最低,荧光非光化学淬灭显著增强且高于其他两个品种。综上所述,在PEG胁迫下抗旱品种的生长受抑制程度最小,清除氧自由基能力较强,光能利用率高。     

郑麦7698加工品质及配粉特性研究

为明确郑麦7698的加工品质及配粉特性,以加西2号和美麦DNS为对照,对郑麦7698、新麦26和周麦22的粉质特性及加工品质进行了分析,并检测了郑麦7698与新麦26、周麦22以不同比例配粉所得混合粉的面包烘焙品质和面条蒸煮品质.结果表明,郑麦7698和新麦26的蛋白质含量、湿面筋含量及粉质参数均达到国家优质强筋小麦的标准,周麦22为中筋小麦品种.郑麦7698、加西2号、美麦DNS和新麦26等4个小麦品种的面包烘焙品质优良,面包评分分别为85.3、85.7、88.5和95.3.当郑麦7698与新麦26配粉比例分别为30∶70和50∶50时,其面包评分分别为95.0和93.8,显著高于郑麦7698单粉,说明对郑麦7698面粉配以适量的新麦26可显著提高郑麦7698的面包烘焙品质.郑麦7698的面条加工品质最优,其面条评分为92.4.郑麦7698与周麦22配粉比例分别为70∶30、50∶50和30∶70时,面条评分分别为89.3、83.6和79.4,说明对周麦22配以适量的郑麦7698可显著改善用麦22的面条加工品质.郑麦7698为面包面条兼用型品种,通过配粉可生产出高质量的面包粉和面条粉.     

不同小麦品种对干旱锻炼响应的综合评价

为明确不同小麦品种对干旱锻炼响应的差异,采用PEG6000模拟干旱胁迫,选取江苏、山东、河南、河北等地大面积种植的110个小麦品种进行水培试验,分析了不同小麦品种叶片相对含水量、叶面积、地上部干鲜重、根干鲜重、植株干物质积累量、根系形态、脯氨酸含量、可溶性总糖含量和蔗糖含量等14个指标的锻炼系数,通过主成分分析、聚类分析方法对这些品种的锻炼响应进行综合评价。结果表明,干旱胁迫下经锻炼处理的植株各指标总体均值大于未经锻炼处理的植株。小麦不同指标的锻炼系数存在差异,其中,可溶性糖、脯氨酸等渗透物质含量的锻炼系数较大。采用主成分分析将14个形态及生理指标综合成4个相互独立的综合指标,其累计贡献率为77.178%;根据主成分综合得分评价值进行系统聚类,可将110个小麦品种分为锻炼敏感型和锻炼不敏感型两大类,前者包括扬麦158、晋麦33、济麦22、豫麦47、洛旱11等81个品种;后者包括淮麦20、淮麦28、泗水38、苏麦188等29个品种。     

铬(Cr~(6+))胁迫对不同基因型小麦种子萌发及幼苗抗氧化和渗透调节的影响

为明确小麦种子萌发对Cr~(6+)胁迫响应的品种间差异及其Cr~(6+)耐性差异的生理机制,以耐Cr~(6+)品种扬麦16和Cr~(6+)敏感品种豫麦51为材料,研究了不同浓度的Cr~(6+)(0、10、50、100、150μmol·L~(-1))处理对种子萌发、α-淀粉酶活性、幼苗生长、活性氧水平、抗氧化酶活性和渗透调节物质含量的影响。结果表明,10mol·L~(-1) Cr~(6+)处理下,小麦种子的萌发过程未受到明显影响。随着Cr~(6+)处理浓度的进一步增加,小麦种子发芽势、发芽率、根长逐渐下降,扬麦16受抑制的程度较豫麦51轻;种子α-淀粉酶活性、根系可溶性蛋白和可溶性糖含量呈现先升后降的趋势;根系游离脯氨酸、丙二醛、O_2~和H_2O_2含量逐渐升高。相同浓度Cr~(6+)处理下,扬麦16的种子α-淀粉酶活性、根系可溶性糖和游离脯氨酸含量显著高于豫麦51,而根系丙二醛、O_2~和H_2O_2的含量显著低于豫麦51。在Cr~(6+)胁迫下,小麦根系SOD、POD、APX和GR的活性总体上呈现先升后降的趋势。在高浓度Cr~(6+)(150mol·L~(-1))处理下,扬麦16的种子α-淀粉酶、根系SOD、POD、APX和GR活性受抑制程度均明显小于豫麦51。     

硅对铬胁迫下小麦幼苗超微结构和铬吸收积累的影响

为探讨水培条件下外源硅对小麦铬毒害的缓解效应,以小麦品种京冬8号为材料,设置2种不同的铬浓度(0.4和0.8 mmol· L-1)和3种不同的硅浓度(0.5、1.0和1.5 mmol· L-1)梯度,研究了铬胁迫下硅对小麦幼苗铬吸收积累和超微结构的影响.结果表明,0.4 mmol·L-1铬胁迫下,硅浓度达0.5mmol·L-1时可以有效抑制小麦根系对铬的吸收积累,显著降低根系铬浓度和富集系数;0.8 mmol·L-1铬胁迫下,硅浓度达到1.0 mmol·L-1时可以有效抑制小麦根系对铬的吸收积累,显著降低根系铬浓度和富集系数.硅处理有使小麦叶鞘和叶片的铬浓度、富集系数和转移系数整体升高的趋势.硅可以减轻铬胁迫对小麦细胞超微结构的伤害,维持细胞形状的规则和结构的完整性,维护膜系统结构的正常和完整,恢复叶绿体的形状和类囊体结构的整齐规则,使线粒体结构恢复完整及内嵴结构清晰,恢复细胞核的完整性,且在试验范围内随硅浓度增大,缓解程度逐渐增大.     

Difference In Tolerance To Potassium Deficiency Between Two Maize Inbred Lines

Abstract

Northeast China Produces An Abundance of Maize (Zea Mays L.), and Improvement of Maize Yield At This Region Correlates Closely With Ensure Food Supply Safely of China. in Recent Years, Deficiency Or Relative Deficiency of Potassium (K) in The Soil Is An Important Limitation To Maize Production. Maize inbred Lines Tolerant To K Deficiency (T) and Sensitive To K Deficiency (C) Were Hydroponically Grown in 1/2 Hoagland Solution To Study The Possible Mechanism of Maize Tolerance To Potassium Deficiency From Physiological Point of View. With The Reduction of K⁺ Concentration, Dw of The Plant Became Apparently Greater in T Than in C, The Symptom of Potassium Deficiency Advanced in C. Under K Deficiency, The Taproot Elongation increased and Root Top Ratio Decreased To A Greater Degree in C Than in T, C Had Fawer Lateral Roots. T Had A Stronger K⁺-Uptake Ability Than C, and The Difference Was More Obvious in Culture Solution With A Lower K⁺ Concentrations of Culture Solution. K⁺ Dependent H⁺ Extrusion From The Root Treated With K⁺ Deficiency Was Larger in T Than in C.     

石墨炉原子吸收分光光度法测定稻米中铬含量的不确定度分析

采用石墨炉原子吸收分光光度法测定稻米中铬含量,根据《测量不确定度评定与表示》(JJF1059-1999)有关规定分析不确定度的来源。结果表明,稻米中铬的含量为0.11 mg/kg,扩展不确定度为0.02 mg/kg(包含因子k=2)。不确定度主要由样品处理过程和测量结果的相对标准偏差所引入。     

Na+/K+-ATPase Activation by cAMP in the Midgut of Lutzomyia longipalpis (Lutz & Neiva, 1912; Diptera: Psychodidae)

Lutzomyia longipalpis (Lutz & Neiva, 1912) females have been intensively studied regarding the regulation of midgut pH. The mechanisms involved in pH regulation are complex, and some aspects remain to be clarified. Here, we investigated the role of the Na⁺/K⁺-ATPase pump as an electrochemical potential generator and its modulation by the second messenger cAMP in the midgut of female L. longipalpis. Our results suggest that not only may Na⁺/K⁺-ATPase be the main generator of an electrochemical potential across membranes in the midgut of female L. longipalpis, but also its activity is positively regulated by cAMP. cAMP-mediated Na⁺/K⁺-ATPase pump activity might be necessary to maintain the transport of the nutrients produced during blood digestion.     

Effect of different Cs concentrations on overall plant growth and Cs distribution in soybean

The absorption and dynamics of Cs in crops can be measured and examined using not only ¹³⁷Cs but also ¹³³Cs, a stable isotope which can be analyzed in a regular laboratory. When ¹³³Cs is used, however, the concentration of added ¹³³Cs must be set higher than that in the soil solution due to the detection sensitivity of inductively coupled plasma optical emission spectrometry (ICP-OES). There is concern that such high Cs concentrations may adversely affect crops and interfere with Cs dynamics. Using soybean as a test product, we first examined the initial growth of soybean cultivated under exposure to solutions with different ¹³³Cs concentrations. In combination with each ¹³³Cs concentration, two potassium (K) concentrations were tested. Results show that at both K concentrations, growth was inhibited under ¹³³Cs concentrations higher than 1 × 10^?3 mol L^?1. Soybeans cultivated at ¹³³Cs concentrations higher than 1 × 10^?6 mol L^?1 can be subject to ICP-OES for measuring ¹³³Cs concentrations in the plant tissue. Next, soybeans cultivated under different ¹³³Cs concentrations throughout growth were examined for Cs distribution in the plants. The distribution patterns of Cs in soybean plants cultivated at ¹³³Cs concentrations equivalent to those found in the soil were almost identical to those in plants cultivated at measurable ¹³³Cs concentrations (1 × 10^?6–1 × 10^?4 mol L^?1) as measured with ICP-OES. Therefore, in our investigation, ¹³³Cs distribution in soybean plants treated with up to 1 × 10^?4 mol L^?1 was considered equivalent to that in plants cultivated in the field.     

Impact of ocean acidification on energy metabolism of oyster, Crassostrea gigas--changes in metabolic pathways and thermal response

Climate change with increasing temperature and ocean acidification (OA) poses risks for marine ecosystems. According to Pörtner and Farrell [1], synergistic effects of elevated temperature and CO₂-induced OA on energy metabolism will narrow the thermal tolerance window of marine ectothermal animals. To test this hypothesis, we investigated the effect of an acute temperature rise on energy metabolism of the oyster, Crassostrea gigas chronically exposed to elevated CO₂ levels (partial pressure of CO₂ in the seawater ~0.15 kPa, seawater pH ~ 7.7). Within one month of incubation at elevated Pco₂ and 15 °C hemolymph pH fell (pH_e = 7.1 ± 0.2 (CO₂-group) vs. 7.6 ± 0.1 (control)) and P_eco₂ values in hemolymph increased (0.5 ± 0.2 kPa (CO₂-group) vs. 0.2 ± 0.04 kPa (control)). Slightly but significantly elevated bicarbonate concentrations in the hemolymph of CO₂-incubated oysters ([HCO⁻ ₃]_e = 1.8 ± 0.3 mM (CO₂-group) vs. 1.3 ± 0.1 mM (control)) indicate only minimal regulation of extracellular acid-base status. At the acclimation temperature of 15 °C the OA-induced decrease in pH_e did not lead to metabolic depression in oysters as standard metabolism rates (SMR) of CO₂-exposed oysters were similar to controls. Upon acute warming SMR rose in both groups, but displayed a stronger increase in the CO₂-incubated group. Investigation in isolated gill cells revealed a similar temperaturedependence of respiration between groups. Furthermore, the fraction of cellular energy demand for ion regulation via Na⁺/K⁺-ATPase was not affected by chronic hypercapnia or temperature. Metabolic profiling using ¹H-NMR spectroscopy revealed substantial changes in some tissues following OA exposure at 15 °C. In mantle tissue alanine and ATP levels decreased significantly whereas an increase in succinate levels was observed in gill tissue. These findings suggest shifts in metabolic pathways following OA-exposure. Our study confirms that OA affects energy metabolism in oysters and suggests that climate change may affect populations of sessile coastal invertebrates such as mollusks.     

铬胁迫对水稻幼苗生长和生理特性的影响

用不同浓度的重铬酸钾溶液处理水稻幼苗,研究了重金属铬对水稻幼苗生长及生理特性的影响.结果表明,随着铬胁迫浓度的提高,水稻幼苗的株高、单株鲜重、主根长等生长指标及叶绿素含量、SOD活性、POD活性、根系活力等生理指标均逐渐降低,而MDA含量逐渐升高.在各项指标中,水稻幼苗主根长和根系活力受到显著抑制时的重铬酸钾浓度为10mg/L,低于株高、单株鲜重、叶绿素含量、SOD活性、POD活性受到显著影响的浓度(50mg/L),说明水稻根系生长对Cr6+胁迫较地上部分更敏感.     

水杨酸对铬胁迫下大豆种子萌发的影响

以"日本青"大豆(Glycine max L.)种子为材料,研究了铬对大豆种子萌发的胁迫作用及水杨酸(Salicylic acid,SA)对铬胁迫的缓解效应。结果表明:在0～200 mg·L-1铬浓度范围内,随铬胁迫浓度的增加,大豆种子的发芽率、发芽指数和活力指数降低,大豆下胚轴丙二醛含量和相对电导率增加;铬胁迫显著(P<0.05)抑制大豆种子萌发的浓度为100 mg·L-1。0.05 mmol·L-1SA可缓解铬对大豆种子萌发的毒性。