土壤水分和氮磷营养对冬小麦根苗生长的效应

在模拟田间原状土容重的条件下土培,研究了土壤水分和氮磷营养对小麦根苗生长及水分利用的效应。结果表明：在ＳＲＷＣ为４０％－７０％范围内,土壤水分亏缺严重,ＲψＷ和ＥＴ显著降低,根苗生长严重受阻,ＲＬ变短,ＲＤＷ降低,ＬＡ和ＰＤＷ减少;随着土壤水分趋于良好,ＲψＷ、ＥＴ和ＬＡ明显增加,ＲＤＷ和ＰＤＷ在ＳＴＷＣ为５５％－６２％之间时最大,而ＳＲＷＣ在５５％上下时ＲＬ达最长;土壤轻度干旱有利根系下扎,土壤     

Screening for Drought Tolerance: Evaluation of Seed Germination and Seedling Growth for Drought Resistance in Legume Plants

Experiments were performed to evaluate seed germination and seedling growth in simulated drought as screening techniques for drought tolerance raring. Several laboratory screening tests were evaluated for ability to estimate drought resistance in 18 cultivars of legume plants (field bean, soybean, field pea, lupine). Drought was simulated by a water solution of mannitol of chemical water potential ψ= -0.3 and -0.6 MPa. Both solutions significantly affected seed germination (final germination and promptness index) and seedling growth parameters (seedling height, dry matter of shoot and root as well as leaf injury by drought and high temperature). The tested cultivars could be grouped as drought resistant and drought susceptible plants. Drought tolerance ratings of legume plants in the laboratory tests were, on the whole, consistent with the ratings based on estimation of direct effects of soil drought on seed yield in field experiments. Measurements of electroconductivity of leaf diffusate to evaluate invisible injury caused by drought or high temperature were found to be an adequate criterion for drought tolerance rating. It is concluded that tolerance to drought stress in growing seedlings can be screened for by using mannitol containing nutrient solution. According to the results collected in this research, varieties differences in seed germination, seedling growth and leaf injury affected by drought or heat temperature were evident, however, not all treatments appeared to be equally useful for screening of legume species cultivars.     

抗旱剂对玉米出苗和幼苗生长的影响

用抗旱浸种剂和拌种剂复合处理玉米种子 ,在较低的土壤水分条件下 ,可提高玉米种子的出苗率和出苗速度 ,促进幼苗根系生长。同时能提高叶绿素含量和可溶性糖含量 ,降低游离脯氨酸含量 ,植株保水抗旱力明显增强。试验结果表明 ,出苗率、苗高、苗干重、根长、根干重、根体积、根冠比、叶绿素含量、可溶性糖含量、脯氨酸含量处理间均有显著差异 ,其中用浸种剂浸 8h和用 2 %拌种剂复合处理的效果最好 ,显著优于空白对照和 8h清水浸种处理。     

NaCl胁迫对小麦种子萌发与幼苗生长的影响

以小麦烟农19和克旱16为材料,研究NaCl胁迫下对小麦不同品种种子萌发与幼苗生长的影响。结果表明：在NaCl胁迫下,小麦两个品种的发芽率、苗高、根长、苗重、根重、根数等均随浓度的增加呈下降趋势,其中NaCl胁迫对苗重与根重的影响较大,依品种不同在浓度25mmol/L和50mmol/L时显著低于对照。小麦两个品种对NaCl的耐受性不同,烟农19较克旱16耐NaCl胁迫。     

红花种子萌发期抗旱性鉴定与评价

为了探索红花耐旱机制及为选育耐旱品种提供理论依据,本文研究了干旱胁迫对红花种质萌发及生长状况的影响。采用聚乙二醇(PEG-6000)模拟干旱胁迫处理,对干旱胁迫下10个红花种质萌发率及幼苗生长指标进行测量,并对各测量指标进行模糊隶属函数分析。结果表明低浓度的PEG对红花种子萌发有一定程度的促进作用；当浓度为15%时,对各指标的抑制作用明显,因此本研究选用15%的PEG浓度鉴定红花种质的抗旱性。在干旱胁迫下红花发芽势、发芽率、下胚轴重、子叶重等降低,胚芽生长受到抑制,干旱对不同种质的根长和根重的影响不一致。通过种子萌发抗旱指数及隶属函数值对红花种质萌发期抗旱性进行综合评价,其中BXY1465为萌发期抗旱性强的材料,BXY512、BXY426、BXY1466以及BXY1859属于萌发期抗旱性中等的材料,BXY1805、BXY2527、BXY2110、BXY750以及WH0086属于萌发期抗性弱的材料。     

Chemical priming with urea and KNO<Subscript>3</Subscript> enhances maize hybrids (<Emphasis Type="Italic">Zea mays</Emphasis> L.) seed viability under abiotic stress

Seed priming is a method to improve germination and seedling establishment under stress conditions. The effect of seed priming in chemical solutions such as urea and KNO₃, on protein and proline content, germination, and seedling growth responses of four maize (Zea mays L.) hybrids under drought and salt stress conditions was studied in a controlled environment in 2010. Treatments included stress type and intensity at five levels: moderate drought (MD), severe drought (SD), moderate salt (MS), severe salt (SS), and control (C1, without stress), three seed priming types including water (C2, as control), KNO₃, and urea (as chemical priming), and four maize hybrids including Maxima, SC704, Zola, and 307. The results showed that the highest germination percentage (Ger %), germination rate (GR), seedling length (SL), radical length (RL), and seedling to radical length ratio (S/R) were achieved in no stress treatments and most proline content in SD treatment. Urea priming led to more Ger%, GR, and SL compared to other primers and treatment under KNO₃ priming resulted in higher RL compared to other primers. Chemical priming had no effect on S/R and proline content. Also, in terms of most traits, no difference was found among the four hybrids. Results showed that salt stress could affect GR and RL more than the drought stress. Drought stress affected germination percentage and S/R more than the salt stress. Both stresses decreased all measured parameters, except protein and proline content which were increased remarkably, and more under drought compared to salt stress. Based on proline content, hybrid 304 appeared to be more resistant to stress than other hybrids. Generally, KNO₃ and urea alleviated effects of both stresses and led to increased germination and seedling growth as well as the root length. Therefore, priming could be recommended for enhancing maize growth responses under stressful conditions.     

外源5-ALA对干旱胁迫下玉米种子萌发及幼苗生长的影响

干旱是影响西北地区玉米生长发育的主要因素之一,5-氨基乙酰丙酸（5-ALA）是一种潜在的生理活性物质,具有增强植物抗逆性的作用。为了探明干旱胁迫下5-ALA对玉米种子萌发和幼苗生长的缓解效应,同时筛选出缓解的最佳浓度,以玉米品种“郑单958”为材料,以蒸馏水为对照,研究20% PEG 6000模拟干旱胁迫下不同浓度5-ALA（0、5、10、15、20、25、30mg/L）对玉米种子萌发及幼苗生长的影响。结果表明,与对照相比,干旱胁迫下玉米种子的萌发和幼苗生长受到明显抑制,幼苗的渗透调节物质含量减少,抗氧化酶活性降低,丙二醛（MDA）含量增加,质膜透性增大。与0mg/L 5-ALA处理相比,一定浓度（25mg/L）的5-ALA能明显缓解干旱胁迫对玉米幼苗造成的伤害,玉米幼苗的主根长、芽长、根鲜重、芽鲜重、根干重和芽干重显著增加,种子发芽势和发芽率显著提高了76.92%和65.52%,脯氨酸、可溶性糖和可溶性蛋白含量分别上升了136.82%、81.36%和121.26%,超氧化物歧化酶、过氧化物酶和过氧化氢酶活性分别增加了200.58%、182.10%和536.56%。MDA含量和细胞质膜透性则分别下降64.54%和68.21%。5-ALA的缓解作用具有明显的剂量效应,其中以浓度25mg/L处理效果最好。     

外源SLs和纳米K2MoO4对干旱胁迫下油菜种子萌发的影响

干旱胁迫是油菜种子萌发和生长发育的主要限制因子之一。以甘蓝型油菜品种Q2（抗旱型）和秦优8号（干旱敏感型）为试验材料,研究干旱对油菜种子萌发的影响,探讨外源生长调节物质独脚金内酯（SLs）和纳米材料（n-K₂MoO₄）对干旱胁迫下油菜种子萌发的生理调控作用。结果表明,干旱胁迫显著抑制种子萌发,SLs和n-K₂MoO₄均可显著提高发芽率,增加幼苗干重和子叶叶绿素含量,提高超氧化物歧化酶、过氧化物酶活性及可溶性糖、脯氨酸含量,降低丙二醛含量。0.10µmol/L GR24+0.24mmol/L K₂MoO₄对干旱胁迫下种子萌发和氧化损伤的缓解效应较好。外源SLs和n-K₂MoO₄通过提高油菜种子萌发期的保护酶活性和渗透调节物质含量来提高抗旱性。本研究表明植物激素和纳米材料在农业生产中具有应用价值。     

向日葵高密度遗传连锁图谱构建及两种水分条件下芽期性状的QTL分析

干旱胁迫对向日葵发芽出苗有重要影响。以K55×K58组合衍生的187个F6重组自交系为材料,利用SSR、SRAP、AFLP标记构建向日葵高密度遗传连锁图谱,设置正常水分(CK)和模拟干旱(18%聚乙二醇PEG-6000)两种水分条件,调查9个芽期数量性状,PCR扩增株系,构建一张包含17个连锁群、1105个标记(368个SSR、368个SRAP和369个AFLP)的高密度遗传连锁图谱。该图谱覆盖基因组长度3846.0 c M,平均图距3.48 c M,连锁群长度147.6~295.5 c M,每个连锁群标记数10~165个。两种条件下检测到33个QTL,其中干旱条件下检测到发芽指数、发芽率、胚芽长、胚根长、胚芽鲜重和胚根鲜重6个性状的14个QTL,可解释6.1%~14.0%的表型变异;正常水分(CK)条件下检测到发芽势、胚根长、胚芽鲜重、胚根鲜重、胚根干重和胚芽干重6个性状的19个QTL,可解释6.1%~25.8%的表型变异。两种水分条件下检测到Qefw5-1、Qefw5-2、Qefw5-4、Qrfw5、Qrfw10和Qrl9共6个QTL的遗传贡献率超过10%,此外,还检测到9个影响干旱胁迫与正常水分条件下性状差值的QTL,可能对抗旱性有直接贡献。这些QTL可为向日葵芽期抗旱分子设计育种研究提供重要参考。     

水分胁迫下甜菜幼苗过氧化物酶cprx1基因的半定量表达模式分析

为明确甜菜过氧化物酶cprx1基因在抗旱节水中的功能,利用甜菜品种HI0466(抗旱性较强)、农大甜研4号(抗旱性较弱)为材料,通过已克隆的甜菜cprx1基因序列设计引物,利用半定量RT-PCR方法,对甜菜幼苗根系、叶片中cprx1基因在正常供水及PEG6000模拟水分胁迫1d、3d、5d及复水1d、2d时的表达模式进行分析。结果显示,2个甜菜品种幼苗根、叶中cprx1基因在正常供水情况下均有一定量的表达;在水分胁迫1d均诱导上调表达;水分胁迫至第3天HI0466根、叶中表达量显著增强,而农大甜研4号根、叶中该基因表达受到抑制;胁迫至第5天HI0466根、叶中该基因仍有微量表达,而农大甜研4号根、叶内该基因表达接近停止;复水2d后表达量均恢复至胁迫前水平。     

外源ZnCl2对成县迟蒜盐胁迫响应研究

用不同浓度的ZnCl2对盐胁迫下成县迟蒜鳞茎种子进行处理,对大蒜鳞茎种子萌发、幼苗生长和幼苗中渗透调节物质的含量及4种抗氧化酶活性进行了测定.结果表明,在单一NaCl胁迫下,大蒜鳞茎种子萌发和幼苗的生长受到严重抑制,添加不同浓度ZnCl2后,大蒜鳞茎种子萌发率和幼苗的耐盐性明显增强.添加浓度为10-5 mol/L时,大蒜鳞茎种子萌发率、萌发指数和芽长、根长、发根数以及幼苗鲜重、苗干重、根鲜重、根干重和根体积、抗氧化酶SOD、POD、CAT和APX活性达到最大,可溶性糖、脯氨酸和丙二醛含量降到最低.因此,外源ZnCl2缓解NaCl胁迫对大蒜鳞茎种子萌发和幼苗伤害的最适浓度为10-5 mol/L.     

Effects of Sugar Beet as a Preceding Crop on Cotton

Cotton ( Gossypium hirsutum L.) is one of the most profitable cash crops in Greece. It is usually grown as a monoculture but it is also found in rotation systems with other plant species including sugar beet ( Beta vulgaris L.). Poor cotton performance following sugar beet was persistently reported by farmers. Glasshouse and field experiments were conducted to determine whether: 1) sugar beet as a preceding crop affected seed germination, seedling growth and yield of cotton; and 2) N fertilization can minimize the effects of sugar beet. Seedling growth was diminished by sugar beet extracts; emergence, seed-cotton, stalks and biomass of cotton in pots were affected by the soil incorporation of sugar beet residues; and emergence, flowers, bolls and seed-cotton production in the field were also affected by the soil incorporation of sugar beet residues. These harmful effects were eliminated by N fertilization.     

Diallel cross analysis of seed germination traits in sugar beet

A diallel cross design, involving six diploid O-type lines and their cytoplasmic male sterile (CMS) equivalents was used to examine the genetic control of characters determining seed viability and vigor of seed and seedling in sugar beet. Six characters including percentage of germination, seedling establishment, weight of 1000 germs, seedling vigor, speed of germination, and monogermity were analyzed. Additive genetic effects were shown to be highly important for all characters and significant dominance effects were found for the percentage of germination and seedling establishment, weight of 1000 germs, and rate of monogerm seeds produced by multigerm plants. There were significant reciprocal variations for most characters, indicating that maternal effects and differences of self-incompatibility mechanisms may influence the expression of some characteristics related to the amount of viable seeds produced in plant. Variance of genotypes for seedling vigor and speed of germination was nonsignificant, indicating that both characters are mainly affected by environmental factors. The relative importance of heritability estimates and the ratio of GCA, SCA, and environmental variances to phenotypic variances were calculated for all the traits examined. It is suggested that seed traits are as important as root quality traits for the development of sugar beet varieties. This revised version was published online in August 2006 with corrections to the Cover Date.     

Root characteristic system improves drought tolerance in orchardgrass

Plant genotypes with higher drought tolerance through improved root characteristics are poorly studied in orchardgrass. In the current research, 30 orchardgrass genotypes were polycrossed and the resulting half‐sib families evaluated under both normal and water stress environments. Under water stress conditions, values for most root traits decreased at 0–30 cm soil depth, while at 30–60 cm depths, the root length (RL), root area (RA), root volume, percentage of root dry weight (RDW) and the ratio of root to shoot were increased. We identified drought‐tolerant genotypes with a high combining ability for root characteristics and a high yield potential. High estimates of heritability as well as genetic variation for root traits indicated that phenotypic selection would be successful in order to achieve genetic progress. Indirect selection to improve dry matter yield was most efficient when selecting for RL and RDW under water stress conditions. Significant associations between a drought tolerance index and RL, RA and root volume confirmed the importance of these traits in conferring drought tolerance of orchardgrass.     

甜菜幼苗光合生理对干旱胁迫的响应

干旱胁迫是抑制甜菜生长发育和影响产量的重要非生物因素。以耐旱型甜菜种质依安一号（V1）和干旱敏感型种质92011/1-6/1（V2）为试验材料,探讨不同耐旱品种甜菜幼苗光合生理对干旱胁迫的响应。研究了干旱胁迫对甜菜幼苗生长发育、总叶绿素含量和表观光合指标的影响。结果表明,干旱胁迫下2种甜菜幼苗的茎粗、根长、株高、叶鲜重、根鲜重、叶干重和根干重均呈下降趋势,V1下降幅度不明显且各指标降低幅度均小于V2;干旱胁迫降低了2种甜菜幼苗的叶绿素含量,叶绿素含量在第7天降到最低,且V1的含量明显高于V2;干旱胁迫使甜菜幼苗的净光合速率、蒸腾速率、叶片气孔导度和胞间CO₂浓度显著下降,V1受到的影响比V2要小。不同耐旱性甜菜品种对干旱胁迫的响应机制存在一定差异,可以进一步分析其抗旱能力,为甜菜的育种、抗逆栽培和稳产提供理论依据。     

PEG模拟干旱胁迫对耐旱型与干旱敏感型甜菜种质形态指标的影响

探讨不同程度干旱胁迫对甜菜苗期生长状况的影响,旨在为耐旱甜菜种质选育与抗逆性研究提供理论依据。本研究以两种耐旱型BGRC16137(V₁)、依安一号(V₂)和两种干旱敏感型92011/1-6/1(V₃)、7412/823-3(V₄)的甜菜种质为材料,采用PEG模拟干旱,以差异显著性检验和逐步回归分析的方法来衡量干旱胁迫对甜菜的影响。随着干旱胁迫程度的增加,4个甜菜种质的幼苗地上部指标、地下部指标与叶片相对含水量都有显著的降低,根冠比逐渐升高。在各种浓度的干旱胁迫下,耐旱型V₁、V₂种质的叶鲜重、叶干重、叶饱和鲜重、根长和根鲜重的下降程度都低于旱敏感型V₃、V₄种质。重度干旱胁迫下,旱敏感型V₃、V₄种质的叶片相对含水量分别比对照组下降37.33%、43.90%,而耐旱型V₁、V₂种质仅下降14.94%、20.45%。结果表明耐旱型甜菜种质通过增加叶鲜重、叶干重、叶饱和鲜重、根长、根鲜重和叶片相对含水量来适应干旱胁迫。     

甜菜苗期抗旱性鉴定及指标筛选

为筛选甜菜苗期抗旱种质资源及确定抗旱指标。本研究以国家甜菜种质中期库提供的24份甜菜种质资源为材料,采用PEG-6000模拟干旱胁迫的方法,以正常生长条件的Hoagland水培溶液(CK)为对照,对甜菜幼苗进行7天的6% PEG-6000处理,并测定地上部和地下部的表型指标。结果表明,干旱胁迫对叶鲜重、根鲜重、叶饱和鲜重和叶干重的影响较大,降幅均超过50%;且干旱胁迫后甜菜种质根冠比明显增加。聚类分析将24份甜菜种质分为四类,其中ZT000516单独为一类,是抗旱性最强的种质资源;第二类为抗旱性较强的种质分别为ZT000078、ZT000547、ZT000247;第三类为中等抗旱型种质共7份;第四类为抗旱性弱种质共13份,其中ZT001698、ZT001398为干旱高度敏感型种质资源。通过逐步回归分析筛选出叶干重和叶饱和鲜重与D值极显著相关。ZT000516为抗旱性强种质资源,ZT001698、ZT001398为干旱敏感型种质资源,叶干重和叶饱和鲜重可以作为甜菜苗期干旱胁迫快速准确地鉴定指标。     

甜菜种质资源苗期耐旱性综合评价

对336份甜菜种质资源苗期的15个表型和生理生化指标进行测定，并通过隶属函数、主成分分析、聚类分析和相关性分析方法对甜菜种质资源耐旱性进行综合评价。结果表明，干旱胁迫后叶干重、株高、根长、叶鲜重、根鲜重、根干重、叶片饱和鲜重和叶片相对含水量等指标均显著降低，根冠比、可溶性糖、可溶性蛋白和脯氨酸含量等4个指标均显著高于对照。主成分分析将15个单一指标转化为6个综合指标，可代表原始数据信息的75.95%。聚类分析将336份甜菜种质资源分为5个类群，其中耐旱性强种质16份，耐旱性较强种质49份，耐旱性中等种质109份，耐旱性较弱种质79份，耐旱性弱种质83份。相关性分析结果显示，胚轴直径、株高、根长、叶鲜重、根鲜重、根干重、叶干重、叶片饱和鲜重、叶片相对含水量和根冠比与D值呈显著相关性。     

野生月见草种子萌发期的抗旱性研究

以采自大庆的野生月见草种子为材料,在5％、10％、15％、20％的PEG-6000的胁迫下,对种子的发芽率、发芽势、发芽指数、活力指数以及苗长进行测定,并根据测定的数值计算出种子活力的指标以及综合所有指标进行综合测定评价.结果表明,轻度干旱条件(5％)有利于野生月见草生物量的积累及其根系的生长,但在10％以及以上浓度的干旱胁迫下其萌发以及生长受到不同程度的抑制.     

PEG胁迫对几个臭椿种源种子萌发的影响

采用0.0%(ck)、2.5%、5.0%、7.5%(w/v)4种浓度的聚乙二醇PEG(6000)对几个臭椿种源种子的萌发进行渗透胁迫处理,结果表明:随着PEG浓度的升高,臭椿种子的发芽率、发芽指数、活力指数均呈下降趋势;发芽后幼苗高、鲜重也呈下降趋势,而根长呈上升趋势;不同种源间的变化趋势相似,但变化幅度有明显差异.综合评价初步认为,河南宝丰种源耐旱性最强,甘肃会宁种源耐旱性较强,宁夏平罗种源耐旱性一般,陕西周至种源耐旱性相对较弱.在实验室环境条件下,臭椿种子萌发及其发芽苗可忍受5.0%～7.5%的PEG渗透胁迫.