水分胁迫对玉米叶片水分代谢的影响

试验在盆栽人工控制水分的条件下,比较了不同水分胁迫强度对不同抗旱性玉米杂交种叶片水分代谢的影响。结果表明,水分胁迫下玉米叶片水势、相对含水量、气孔导度和蒸腾速率均明显降低,随胁迫程度增强,降低幅度增大。其中叶片水势和叶片相对含水量与品种抗旱性密切相关,蒸腾速率和气孔阻力与品种抗旱性关系不明显。     

干旱胁迫对大麦叶片表皮蜡质含量及主要生理指标的影响

为了探究大麦对干旱胁迫的反应机制,采用裂区设计研究了干旱胁迫对不同大麦品种灌浆期旗叶和旗叶鞘表皮蜡质含量及主要生理指标的影响。结果表明,与正常水分处理相比,干旱胁迫可促进大麦表皮蜡质的合成;大麦不同品种间蜡质含量差异显著,抗旱品种的蜡质含量显著高于干旱敏感品种。在干旱胁迫下,大麦叶片相对含水量、叶绿素含量及气孔导度显著降低,且抗旱品种降低幅度较干旱敏感品种缓慢;蒸腾速率和胞间CO2浓度显著增加,且抗旱品种的增加幅度低于干旱敏感品种。品种因素对大麦叶片蜡质含量、净光合速率、气孔导度的影响较水分处理的影响大。大麦表皮蜡质含量与水分利用效率呈显著正相关,表明表皮蜡质对提高大麦抗旱性有一定积极意义。     

梯度干旱胁迫对水稻叶片光合和水分状况的影响

采用温室营养液培养方式,通过添加0%、10%、20%、30%PEG6000模拟干旱胁迫,对水稻幼苗叶片的光合作用和水分状况进行比较分析。结果表明:1)在干旱胁迫下,水稻叶片的光合速率、气孔导度、叶肉导度、总导度和叶绿体内CO2浓度等都显著降低;2)在干旱胁迫条件下,限制光合作用的非气孔限制值并没有显著提高,而气孔限制值则大幅提高;与正常水分条件相比,扬稻6号和汕优63在30%PEG干旱胁迫下气孔限制值分别提高了42%和81%;3)光合速率与气孔导度、叶肉导度、总导度及叶绿体内CO2浓度呈正相关;4)在重度干旱胁迫下(20%和30%),叶片水势和含水量都显著下降,并且叶片水势与气孔导度、叶肉导度和总导度呈正相关。因此,气孔关闭导致的叶绿体内CO2浓度降低是限制光合作用的最主要因素,同时叶片水势的降低增加了叶片内CO2传输的阻力。     

干旱胁迫对燕麦叶片气孔和叶肉细胞超微结构的影响

为了解干旱后燕麦解剖结构的变化,以燕麦品种白燕2号为材料,通过盆栽控水试验,设置正常供水、轻度干旱和重度干旱三个不同水分处理(土壤含水量分别为田间持水量的75%、60%和45%),研究了干旱胁迫对燕麦叶片渗透调节物质含量、气孔和叶肉细胞超微结构的影响。结果表明,正常水分条件(对照)下,燕麦叶片脯氨酸和可溶性糖含量较低,表皮细胞皱褶,气孔关闭或微张,叶肉细胞内细胞器形状规则,结构清晰。与对照相比,轻度干旱胁迫下,燕麦叶片脯氨酸和可溶性糖含量增加,叶片表皮细胞饱满,气孔开启度较大,叶绿体形状变圆,近球状,线粒体外被膜膨胀,但结构未见明显损伤;重度干旱胁迫下,叶片脯氨酸和可溶性糖含量极显著增加,表皮细胞干瘪,气孔保卫细胞膨胀,气孔关闭,气孔器下陷。重度干旱胁迫下,燕麦叶绿体和线粒体受到的损伤较大,叶绿体内基粒、基质类囊体降解,出现较大的空腔;线粒体外被膜断裂,内含物流失;细胞核染色质凝聚,叶绿体之间出现嵌合现象。因此,干旱胁迫能诱导燕麦叶片渗透调节物质的积累和细胞超微结构的改变,渗透调节物质增幅和细胞超微结构的破坏程度随着土壤有效水分含量的降低而上升,但在细胞超微结构上也出现抗性反应,表明燕麦具有较强的抗旱性。     

玉米抗旱性与生理生化指标关系的研究

以目前我国主栽的14个玉米品种为试材,研究了玉米耐旱指数与生理生化指标的关系。结果表明,干旱胁迫下玉米耐旱指数与叶片相对含水量、脯氨酸含量及可溶性蛋白含量呈极显著正相关,与叶片相对电导率和可溶性糖含量呈极显著负相关,与叶片中丙二醛含量呈显著负相关。上述生理生化指标均可作为玉米抗旱性鉴定指标的参数,用于玉米品种抗旱性的评定。     

外文摘译

91.148茶树抗旱品种的选育指标/A·C·Handique//Assam Review and TeaNews 79(3),1990为了探讨茶树抗旱品种的选育指标,作者以4个抗旱性强和4个抗旱性弱的品种为材料,在缺水条件下对其叶片的生理生化指标分别进行了测定,结果表明:①抗旱性强的品种叶片水势和相对饱涨度较高,气孔扩散阻力较大,脯氨酸和上表皮蜡质含量较     

氮和磷对不同基因型小麦水分状况的影响

为了阐明不同水分条件下氮、磷对不同基因型小麦的水分生理指标的作用及其变化趋势，试验逸用6个不同基因型的小麦进化材料，研究了拔节期各基因型小麦的叶片保水力、叶水势、叶片膜透性与气孔导度。结果表明，当土壤水分充足时，施肥会提高叶片保水力、叶水势，降低叶片膜透性，增加二倍体小走的气孔导度，而降低六倍体小走的气孔导度。在水分胁迫下，施肥会提高叶片保水力，降低叶水势、叶片膜透性和气孔导度；而且随小麦染色体倍性从2n→4n→6n的进化方向，小麦叶片保水力、叶水势、叶片膜透性均先降低，然后又升高。     

苎麻抗旱性基因型差异及其生理生化机理研究

同类根型的苎麻基因型抗旱性存在显著差异。在干旱胁迫下，抗旱性强的基因型叶片相对含水量、水势和细胞膜的稳定性高，苎麻叶片游离脯氨酸积累的过氧化物酶活性对干旱胁迫的反应存在基因型差异，随着干旱胁迫加强，抗旱性强的基因型过氧化物酶活性从低到高，而抗旱性弱的基因型则相反。在干旱胁迫０￣１２天内，抗旱性弱的基因型积累游离脯氨酸多于抗旱性强的基因型，而随着胁迫加强（干旱１２￣２４天），抗旱性强基因型游离脯氨酸     

土壤干旱对抗旱品种洛麦9133拔节期生理特性的影响

为揭示冬小麦拔节期对干旱胁迫的响应机制,采用盆栽试验对不同土壤干旱条件下洛麦9133拔节期的生理特性进行了研究.结果表明,拔节期叶水势、叶相对含水率、叶绿素含量、根系活力、蒸腾速率和光合速率均随土壤水分的减少而呈降低趋势;叶饱和亏、叶绿素a/b、叶片可溶性糖含量、脯氨酸含量、质膜透性、POD活性以及水分利用效率均呈增加趋势.这说明在干旱胁迫下,冬小麦通过降低水势、相对含水率、根系活力和蒸腾速率,增加渗透调节物质可溶性糖、脯氨酸含量和增强POD活性等生理上的变化以提高抗旱性,从而使其适应干旱逆境.     

干旱胁迫下不同大豆品系生理指标变化与抗旱性关系的研究

选用同一大豆杂交组合亲本产生的4个品系为试验材料．于营养生长期干旱胁迫条件下,测定叶片相对含水量、脯氨酸含量、叶绿素含量、相对电导率、渗透势等生理指标,并结合株重、粒数、粒重等农艺性状,通过抗旱隶属函数值对各品系的抗旱性级别进行了划分．进而对各品系生理指标与其抗旱隶属函数值做了相关和回归分析。结果表明：相对含水量、叶绿素含量、脯氨酸含量与抗旱性呈正相关;而相对电导率、渗透势与抗旱性呈负相关。综合分析得出4个品系抗旱性从强到弱的次序为：73—2（圆叶紫花）、73—1（尖叶白花）、73—3（圆叶白花）、73—4（尖叶紫花）．     

QTL mapping rolling,stomatal conductance and dimension traits of excised leaves in the Bala × Azucena recombinant inbred population of rice

The identification of markers linked to genes contributing to drought resistance promises opportunities to breed high yielding rice varieties for drought prone areas. Several studies using different mapping populations have previously identified quantitative trait loci (QTLs) for traits theoretically related to drought resistance. A mapping population of 176 F₆ recombinant inbred lines (RILs) derived from two upland rice varieties with contrasting aboveground drought avoidance traits (Bala and Azucena) with a linkage map of 157 markers was used to map QTLs for aboveground leaf morphological and physiological traits related to drought avoidance. Plants were grown for 6 weeks under controlled environmental conditions with three replications. Leaves were excised and placed on a balance. The rate of leaf rolling and water loss was recorded, after which leaf area, dry weight and specific leaf area were characterized. A simple method of estimating time to stomatal closure was employed. A total of 13 QTLs were detected for leaf morphological traits, three for initial transpiration and four for the proportion of water loss required to reach a specific advanced state of leaf rolling. No QTLs were detected for time of stomatal closure or speed of leaf rolling, nor for either water loss or transpiration at stomatal closure despite clear parental differences and moderate heritabilities in most of these traits. The co-location of QTLs for traits measured here and for drought avoidance previously reported from field experiments on chromosome 1, 3 and 5 link the genetics of drought resistance to leaf dimensions and physiology. However, a physiological explanation for a QTL for drought avoidance on chromosome 7 remains elusive.     

Genetic analysis and validation of quantitative trait loci associated with reproductive-growth traits and grain yield under drought stress in a doubled haploid line population of rice (Oryza sativa L.)

Drought is a major constraint for rice production and yield stability in rainfed ecosystems, especially when it occurs during the reproductive stage. Combined genetic and physiological analysis of reproductive-growth traits and their effects on yield and yield components under drought stress is important for dissecting the biological bases of drought resistance and for rice yield improvement in water-limited environments. A subset of a doubled haploid (DH) line population of CT9993-5-10-1-M/IR62266-42-6-2 was evaluated for variation in plant water status, phenology, reproductive-growth traits, yield and yield components under reproductive-stage drought stress and irrigated (non-stress) conditions in the field. Since this DH line population was previously used in extensive quantitative trait loci (QTLs) mapping of various drought resistance component traits, we aimed at identifying QTLs for specific reproductive-growth and yield traits and also to validate the consensus QTLs identified earlier in these DH lines using meta-analysis. DH lines showed significant variation for plant water status, reproductive-growth traits, yield and yield components under drought stress. Total dry matter, number of panicles per plant, harvest index, panicle harvest index, panicle fertility, pollen fertility, spikelet fertility and hundred grain weight had significant positive correlations with grain yield under drought stress. A total of 46 QTLs were identified for the various traits under stress and non-stress conditions with phenotypic effect ranging from 9.5 to 35.6% in this study. QTLs for panicle exsertion, peduncle length and pollen fertility, identified for the first time in this study, could be useful in marker-assisted breeding (MAB) for drought resistance in rice. A total of 97 QTLs linked to plant growth, phenology, reproductive-growth traits, yield and its components under non-stress and drought stress, identified in this study as well as from earlier published information, were subjected to meta-analysis. Meta-analysis identified 23 MQTLs linked to plant phenology and production traits under stress conditions. Among them, four MQTLs viz., 1.3 for plant height, 3.1 for days to flowering, 8.1 for days to flowering or delay in flowering and 9.1 for days to flowering are true QTLs. Consensus QTLs for reproductive-growth traits and grain yield under drought stress have been identified on chromosomes 1 and 9 using meta-QTL analysis in these DH lines. These MQTLs associated with reproductive-growth, grain yield and its component traits under drought stress could be useful targets for drought resistance improvement in rice through MAB and/or map-based positional analysis of candidate genes.     

稻米粒形和垩白度的QTL定位和上位性分析

 利用由181个家系组成的Lemont/特青籼粳交重组自交系群体,以及由161个RFLP、SSR标记和3个形态标记构建的全长为1916.5 cM、覆盖水稻基因组12 条染色体的连锁图,采用线性模型的复合区间作图方法（QTLMapper V10）,对粒长、粒宽、长宽比和垩白度等4个稻米品质性状的数量性状座位（QTL）进行了分析。在水稻的所有12 条染色体上共定位到7个加性主效QTL和19对上位性QTL,其中控制粒长、粒宽、长宽比的主效QTL各2个,控制垩白度的QTL 1个,分别解释12.8%、40.0%、26.0%和42.1%的表型变异;共检测到6对影响垩白度、6对影响粒长、7对影响长宽比的上位性QTL,分别解释52.2%、31.3%和38.2% 的表型变异。结果表明,上位性QTL和主效QTL一样在稻米粒形和垩白度的遗传中起着重要的作用。     

Rice near-isogenic-lines (NILs) contrasting for grain yield under lowland drought stress

The development of near-isogenic-lines (NILs) is a very important tool for both genetic and physiological dissection of drought resistance in rice. Two pairs of NILs differing for grain yield under drought stress were isolated and characterized for yield, yield related traits, and several physiological traits in a range of contrasting environments. In replicated field trials both NIL pairs differed significantly for grain yield under drought stress but showed similar yield potential, phenology, and yield component traits under non-stress conditions. A polymorphism analysis study with 491 SSRs revealed that both NIL pairs are at least 96% genetically similar. These NILs show that small genetic differences can cause large difference in grain yield under drought stress in rice. In both pairs the drought-tolerant NILs showed a significantly higher assimilation rate at later stages both under stress and non-stress conditions. They also had a higher transpiration rate under non-stress condition. The most tolerant NIL (IR77298-14-1-2-B-10) had significantly higher transpiration rate and stomatal conductance in severe stress conditions. In one pair the tolerant NIL had constitutively deeper roots than the susceptible NIL. In the second pair, which had higher mean root length than the first pair, the tolerant NIL had more roots, greater root thickness, and greater root dry weight than the susceptible NIL. Deeper root length may allow tolerant NILs to extract more water at deeper soil layers. It is concluded that enhanced rooting depth is an important strategy for dehydration avoidance and rice adaptation to drought stress, but root architecture might not be the only mechanism causing the significant yield increase we observed in lowland drought stress environments. To further dissect the drought avoidance mechanisms in rice, analysis of root hydraulic properties may be necessary.     

偃展1号×内乡188群体抗小麦赤霉病QTL分析

为给黄淮麦区小麦抗赤霉病育种提供新的抗性资源,以偃展1号/内乡188小麦重组自交系群体为材料,在田间充分发病的情况下,进行连续两年小麦赤霉病抗性鉴定,并通过复合区间作图,分析群体小麦赤霉病抗性的加性QTL、上位性互作及与环境的互作效应。结果表明,两年间亲本偃展1号、内乡188赤霉病抗性差异显著,群体间赤霉病病情指数变幅分别为0.16~0.70和0.26~0.90。对两年赤霉病抗性鉴定结果进行联合分析,检测到5个加性抗性QTL,1对上位性互作QTL,分别解释表型变异的32.39%和3.05%,环境互作很小(1.88%)。在5个加性QTL中,QFHB.caas-5D和QFHB.caas-4D对变异的解释率较大。群体199个家系中,共筛选到19个赤霉病抗性较好且稳定的家系。上述结果对于加快我国黄淮麦区小麦赤霉病抗性育种具有重要的意义。     

水稻胚芽鞘长度与抗旱性的关系及QTL定位

对由水稻品种珍汕97B和旱稻品种IRAT109构建的重组自交系195个株系的胚芽鞘长度及抗旱系数的研究表明,水分胁迫下水稻重组自交系群体的胚芽鞘长度与抗旱系数的相关系数为0.2206**。应用由213个SSR标记构建的遗传连锁图对控制胚芽鞘长度和抗旱系数的QTL进行了定位。检测到胚芽鞘长度和抗旱系数的主效QTL各为13个和5个,单个QTL对表型的贡献率为2.28%～22.65%;在第9染色体上两者的QTL出现在相同的分子标记区间（RM160-RM215）。检测到胚芽鞘长度和抗旱系数的互作位点分别为17对和3对,影响胚芽鞘长度的互作位点联合贡献率为5835%;影响抗旱系数的互作位点联合贡献率为11.93%。控制胚芽鞘长度和抗旱系数的QTL分别与其他研究中控制根系性状（深根干质量、根深、根长、根数等）的QTL位于相同的标记区间。     

Relationship Between Coleoptile Length and Drought Resistance and Their QTL Mapping in Rice

By using a set of recombinant inbred line(RIL)population involving in 195 lines derived from a cross of Zhenshan 97B (lowland variety)and IRAT109(upland variety),the correlation analysis between coleoptile length(CL)and drought resistance index (DRI)and their QTL identification were conducted.There existed a significantly positive relationship between CL and DRI with the correlation coefficient of 0.2206**under water stress conditions.Under normal and water stress conditions,a total of eleven and four QTLs for CL and DRI,respectively,were detected on chromosomes 1,2,4,5,6,7,9,11 and 12 by using a linkage map including 213 SSR markers,which explained 4.84%to 22.65%of phenotypic variance.Chromosomes 1 and 9 possessing the QTLs for DRI harbored simultaneously QTLs for CL,and qCL9 shared the same chromosome location with qDRI9(RM160-RM215).Comparing the QTLs related to drought resistance in other studies,QTLs for CL and DRI were located in the same or adjacent marker interval as those related to root traits,such as number,dry weight,depth,and length of root.Moreover,sixteen and three pairs of epistatic loci for CL and DRI were found,which accounted for 56.17%and 11.93%of the total variation in CL and DRI,respectively.     

QTL Analysis for Seven Quality Traits of RIL Population in Japonica Rice Based on Three Genetic Statistical Models

QTL mapping for seven quality traits was conducted by using 254 recombinant inbred lines (RIL) derived from a japonica-japonica rice cross of Xiushui 79/C Bao. The seven traits investigated were grain length (GL), grain length to width ratio (LWR), chalk grain rate (CGR), chalkiness degree (CD), gelatinization temperature (GT), amylose content (AC) and gel consistency (GC) of head rice. Three mapping methods employed were composite interval mapping in QTLMapper 2.0 software based on mixed linear model (MCIM), inclusive composite interval mapping in QTL IciMapping 3.0 software based on stepwise regression linear model (ICIM) and multiple interval mapping with regression forward selection in Windows QTL Cartographer 2.5 based on multiple regression analysis (MIMR). Results showed that five QTLs with additive effect (A-QTLs) were detected by all the three methods simultaneously, two by two methods simultaneously, and 23 by only one method. Five A-QTLs were detected by MCIM, nine by ICIM and 28 by MIMR. The contribution rates of single A-QTL ranged from 0.89% to 38.07%. All the QTLs with epistatic effect (E-QTLs) detected by MIMR were not detected by the other two methods. Fourteen pairs of E-QTLs were detected by both MCIM and ICIM, and 142 pairs of E-QTLs were detected by only one method. Twenty-five pairs of E-QTLs were detected by MCIM, 141 pairs by ICIM and four pairs by MIMR. The contribution rates of single pair of E-QTL were from 2.60% to 23.78%. In the Xiu-Bao RIL population, epistatic effect played a major role in the variation of GL and CD, and additive effect was the dominant in the variation of LWR, while both epistatic effect and additive effect had equal importance in the variation of CGR, AC, GT and GC. QTLs detected by two or more methods simultaneously were highly reliable, and could be applied to improve the quality traits in japonica hybrid rice.