Unilateral Increase of Auditory Sensitivity following Early Auditory Exposure

A 30-second exposure (priming) to a loud noise induced a long-lasting susceptibility to audiogenic seizures and a 15-decibel decrease in threshold to the Preyer acoustic startle reflex in C57BL/6J mice. Both effects were absent when the subjects were primed in one ear and subsequently tested in the contralateral ear. It was postulated that the primary effect of priming is an increase in auditory sensitivity due to changes in the ear itself or in those parts of the auditory system which receive their input exclusively from one ear.     

不同玉米自交系穗部性状对氮胁迫的反应及其聚类

在低氮和正常施肥条件下,对50个玉米自交系的穗长、穗粗、穗粒重等8个性状进行了对比分析.结果表明,各自交系的穗部性状分别存在极显著差异;在缺氮条件下,自交系的穗重、穗粒重等产量性状,对氮缺乏的反应较敏感,变异范围大;以氮胁迫情况下穗粒重的变化率为指标,把自交系分为氮素高效利用型、氮素利用迟钝型、氮素敏感型和氮素高度敏感型4类,其中Q 3、许178等13个自交系为氮素高效利用基因型;沈137、济533等32个自交系为氮素利用迟钝基因型;凤可1、沈99-718等4个自交系为氮素利用敏感基因型;而综3自交系为氮素高度敏感基因型.     

Effect of leaf removal on photosynthetically active radiation distribution in maize canopy and stalk strength

The objectives of this study were to determine how the distribution of photosynthetically active radiation(PAR) in a maize canopy affected basal intemode strength and stalk lodging.The distributions of PAR within the canopies of two maize cultivars(Zhongdan 909 and Xinyu 41) were altered by removing whole leaves or half leaves in different canopy layers.The results showed that removing whole leaves or half leaves above the three-ear-leaves(R_(AE) and R_(AE/2)) at flowering significantly increased PAR at the ear and interception of PAR(IPAR) from the earto middle of the ear and soil surface.These changes increased the structural carbohydrate content and rind penetration strength(RPS) of the third basal intemode by 5.4-11.6%and reduced lodging by 4.2-7.8%.Removal of the first three leaves below the three-ear-leaves(R_(BE)) before flowering significantly reduced IPAR from the ear to half way below the ear.This reduced the structural carbohydrate content and the RPS of the third basal intemode by 9.1-17.4%and increased lodging by 7.0-11.2%.Removal of the three lowest green leaves(R_B) in the canopy before flowering increased PAR at the bottom of the canopy,but had no effect on the structural carbohydrate content of the basal intemode,the RPS,and the lodging rate.Overall,the results indicated that the key factors affecting the basal intemode strength formation and lodging were PAR at the ear and IPAR from the ear to halfway below the ear.Increasing PAR at the ear and IPAR from the ear to halfway below the ear could enhance lodging resistance by increasing the structural carbohydrate content and mechanical strength of the basal intemode.     

Changes of moisture distribution and migration in fresh ear corn during storage

Understanding of moisture changes in fresh ear corn (Zea mays L.) during storage is imperative for maintaining fresh corn quality. The changes of moisture distribution and migration in fresh ear corn during storage were investigated using low-field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI). Water loss was greater than water migration in fresh ear corn within the first hour of storage; thereafter, water loss was weaker than water migration. With the extension of storage time, the signal intensity of MRI in different parts of sliced fresh corn with cob showed a downward trend, and the rate of signal intensity reduction was higher in the peripheral area than at the central part of sliced fresh corn with cob. The relative proportion of bound water increased with a concomitant drop in that of free water, when the total water content reduced in fresh ear corn under storage. In conclusion, NMR and MRI are useful and non-destructive tools for real-time monitoring of moisture distribution, migration, and loss in fresh ear corn during storage to assess its quality. These results can be used for future design of the preserving and processing conditions for fresh ear corn.     

玉米对干旱胁迫的反应和适应性Ⅱ.玉米雌穗和雄穗生长发育对干旱胁迫的反应

在人工控制和自然干旱条件下就玉米雌穗和雄穗生长发育对干旱胁迫的反应和适应性进行了深入研究。结果表明：在轻度、中度和重度干旱胁迫下，玉米植株上部节间、雄穗穗柄和雄穗长度不同程度地缩短，雄穗抽出缓慢或不能抽出，导致部分花粉在玉米植株顶部叶片形成的封闭筒内散落而成为无效花粉。干旱胁迫下雄穗分枝数和小穗数大幅度下降及雄穗长度的缩短造成的玉米雄穗花粉量明显减少，可供授粉的花粉量不足。与此同时，玉米雌穗生长发育亦受到干旱胁迫的严重影响，雌穗变短变细，基础物质不足，“库”容量显著缩小，而且，玉米雌穗花丝伸长速率下降或不能抽出。干旱胁迫下玉米雌穗和雄穗生长发育方面发生的变化最终导致玉米花期不遇，授粉受精不良，产量不可逆下降。     

水分胁迫后玉米杂交种结穗性变化和抗旱性的关系研究

[目的]研究水分胁迫后玉米杂交种结穗性和抗旱性的关系,为生产上评价和筛选抗旱丰产玉米的品种提供科学依据.[方法]对87份玉米杂交种进行大田正常灌水和干旱胁迫对比试验,对比研究受旱后玉米杂交种结穗性和抗旱性的相应变化.[结果]与正常灌水对照相比,干旱胁迫使杂交种的结穗率和单株产量显著降低.受旱后的结穗率与杂交种的抗旱性呈极显著的正相关.[结论]水分胁迫后玉米杂交种的结穗率与玉米抗旱性的关系密切,水分胁迫后的玉米结穗率可作为玉米抗旱品种筛选的一个重要指标.     

Activity of Corn Silk at Different Days after Silk Emergence

This study was carried out to evaluate the changes in silk activity of two corn cultivars Xundan 518 and Yongyou 618 after silk emergence. Artificial pollination was conducted at different days after silk emergence, and the ear length, ear diameter,barren tip length, 100-grain weight, grain number per ear and grain weight per ear were measured at harvest. The results showed that with the delay of pollination, the number and weight of grains per ear increased at first, peaked at D2 to D4, and decreased subsequently; ear diameter and 100-grain weight showed a downward trend. Correlation analysis revealed that grain number per ear and grain weight per ear were most closely correlated. Rapid silk extrusion and long-lasting silk activity proved that the two corn cultivars Xundan 518 and Yongyou 618 are tolerant to high temperature.     

玉米果穗DUS性状测试的图像处理应用研究

 【目的】评价图像处理法采集和数量化玉米果穗特异性、一致性和稳定性测试（DUS）性状的技术适用性。【方法】以4个品种各50个果穗及8个品种93～107个穗轴为材料,通过图像处理采集玉米DUS测试指南规定的7个性状（穗长、穗粗、穗形、粒顶色、穗轴色、穗行数和籽粒排列形式）,应用多性状整体控制单一比较法分析品种特异性。【结果】穗长、穗粗和穗行数的图像处理误差分别为6.2%、1.6%和0.66%。果穗的穗缘角（穗形）在0～2.22°之间变化,各品种穗行角（籽粒排列形式）均值在89.4°～90.7°之间。穗形等4个质量或假质量性状成功转换为数量性状,信息量随之增加。籽粒顶端颜色在果穗间和果穗侧面间的差异都极其微小,其它性状的果穗侧面间差异与果穗间差异相当或者更小。图像处理容易获得同源样品的更多形态性状,可能导致品种伪差异的风险升高。【结论】图像处理具有客观、高效、低成本地采集和数量化玉米果穗DUS性状和其它更多性状的能力,结合多性状整体控制单一比较法等适当的统计分析技术,将在中国的新品种DUS测试中发挥越来越重要的作用。     

Historical trends in maize morphology from the 1950s to the 2010s in China

The morphology of the plant and ear is a preliminary selection characteristic in breeding new varieties of maize. As new maize cultivars were developed from the 1950s through the 2010s in China, most had changes in both plant and ear morphological characteristics that contributed substantially to maize yield gains. Over the seven decades, plant and ear height fluctuated with a small increase from the 1950s to 2000s, and then a decrease in the 2010s, while the ear ratio and internodes length below the ear decreased significantly. Leaf angles became significantly more upright, especially for the leaves above the ear, and the leaf area per plant improved markedly. Leaf orientation increased from the 1950s to the 2000s then decreased in the 2010s. Tassel size and the anthesis—silking interval were both reduced substantially. Ear diameter, kernel number, and kernel weight increased from the 1950 to the 2000s, then decreased in the 2010s under the same cultivation conditions. We found that modern maize hybrids have a lower plant height, ear height and ear ratio which increased lodging resistance, a more erect leaf which increased high-density planting tolerance, and smaller ears and kernels which facilitated rapid dehydration during late grain filling. These morphological selection criteria, which are suitable for mechanized operations, are proposed as the focus for future maize breeding.     

氮胁迫对不同玉米自交系若干农艺性状和产量的影响

在施氮(N)和不施N条件下,对50个玉米自交系的穗位叶叶绿素含量、株高、穗位高和产量等性状进行了对比分析.结果表明,在N胁迫条件下,自交系的叶绿素含量平均降低5.73%,子粒产量平均下降15.89%,而不同自交系的叶绿素含量以及子粒产量降低幅度差异明显,变幅分别在0~22%和0~50%;N胁迫条件下,穗位叶的叶绿素含量可作为衡量玉米自交系对N胁迫反应敏感与否的生理指标;A 40,Q 3和许178等自交系对N胁迫反应不敏感,是低N条件下N素高效利用自交系,而凤可1,沈99-718,Q 2和综3等自交系对N胁迫反应敏感;在低N胁迫条件下,不同自交系的株高和穗位高的变化增减不一,缺乏规律性.     

晚霜冻害对不同类型小麦产量性状的影响

采用人工智能霜箱模拟自然界晚霜冻害过程,对大穗(s9538、兰考906)、中穗(豫麦21号、陕225)、多穗(临汾7203、鲁资0885299)类型的小麦品种在经历低温处理后产量因素的变化进行了研究.结果表明,多穗型小麦(临汾7203、鲁资0885299)在经历晚霜冻害后比另外两类小麦表现增产,其中单株穗数较对照增加幅...     

NAC类转录因子在玉米未成熟雌穗发育中的作用

为了研究转录因子在玉米雌穗早期发育阶段的差异表达情况,探讨其生物学功能,利用Arizona大学的玉米芯片对未成熟玉米雌穗的早期关键发育阶段进行全基因组表达谱分析.数据标准化之后对差异基因中的转录因子家族进行超几何分析,挑选并分析差异明显的转录因子家族.结果表明,在玉米雌穗发育早期,有1844个基因差异表达,有7个转录因...     

吉林省不同时期骨干玉米黄改系主要性状配合力分析

研究采用NCII设计,以吉V203、PH6WC、郑58、MO17、97144为测验种,与黄早四及5份吉林省不同历史时期主要应用黄改系配制30个测交组合,利用完全区组田间试验,分析黄改系主要性状配合力。结果表明,对黄早四遗传改良因性状而异。单株产量、行粒数、籽粒含水量和出籽率性状无显著变化,保持黄早四原有配合力。而散粉期、吐丝期、穗重、穗长、穗粗、穗行数、百粒重性状则显著改良。改良性状呈现趋势:四-444之后选育的黄改系延迟散粉、吐丝期,推迟生育期;向缩短穗粗方向改良;穗重、穗长、穗行数、百粒重性状向增加或减少两个方向同时改良。综合各性状一般配合力,吉853表现最好。为吉林省玉米黄改系育种、生产应用以及新一轮遗传改良奠定基础。     

玉米主要数量性状对单株产量的效应

通过相关和通径分析,对宁夏种植和自育的60个杂交种(组合)的9个主要性状与单株产量间的关系进行研究.结果表明,各数量性状的变异范围均较大;穗粗、百粒质量、穗长、穗行数和穗位高与单株产量的相关系数达到显著水平;通过通径分析得出,单株产量与其相关性状的直接效应由大到小依次为百粒质量＞行粒数＞穗行数＞穗粗＞穗长＞穗位高＞株高＞茎粗＞秃尖长,确定百粒质量是影响宁夏玉米单株产量的主要因素,其次是行粒数和穗行数.宁夏高产稳产玉米品种应注重选择百粒质量高、行粒数多和穗行数多的品种,同时要求适宜的株高、穗位高和茎粗.     

北京地区八十年代高产小麦新品种主要农艺性状分析

作者通过对北京地区八十年代超标小麦新品种主要农艺性状的分析,发现新品种产量潜力的增加主要是由于提高了一穗粒重,而亩穗数则有减少趋势。这表明,北京地区的小麦育种正在朝着中间型—大穗型方向发展。一穗粒重的增加大部分品种是由于提高了千粒重,而目前北京地区最高产小麦品种北农2号除了粒重有所增加外,主要是由于增加了一穗粒数。作者认为,同时进行千粒重和一穗粒数的综合选择,是提高一穗粒重的有效途径。实践证明,“在保证足够亩穗数前提下侧重攻一穗粒重”的育种方向是可行的。     

不同栽培条件下糯玉米鲜产及构成因素间的相关性分析

[目的]探明不同栽培条件下,泸玉糯9号各穗部主要性状与产量的相关性。[方法]以鲜食糯玉米品种泸玉糯9号为材料,采用"3414"肥效试验,设2种种植方式(直播、移栽)、3种密度(45 000、52 500、60 000株/hm2)处理,对6个穗部性状(穗长、穗粗、秃尖长、行数、行粒数、千粒重)与鲜产进行相关分析。[结果]直播条件下,穗长、穗粗与鲜穗产量呈显著或极显著正相关;移栽条件下,各性状与鲜穗产量间的相关性表现各不相同;糯玉米高产目标性状要建立在不同品种、栽培措施基础上进行抉择。[结论]该试验为糯玉米高产提供理论基础。     

高产水稻品种主要经济性状遗传分析及其超高产育种策略的探讨

利用20个高产水稻品种(系),研究了与产量有关的12个经济性状的基本遗传参数,并进行了主成分分析.结果表明穗数/m2、产量、株高、千粒重的遗传力较高,结实率、干物重、颖花量相对较低;剑叶面积、穗下节长、穗数/m2、颖花量、实粒数/穗、单株产量、单株干重和千粒重均与产量呈显著或极显著相关关系;入选品种主要特征性状为产量、实粒数/穗、单株穗数、株高、穗数/m2.以上结果说明,在淮北地区气候条件下,超高产育种应采取在单位面积足穗基础上,提高每穗粒数和千粒重的育种策略.     

玉米穗粒重与果穗三维几何特征关系的定量研究

【目的】从穗粒重与果穗三维几何关系的角度探索籽粒产量的制约因素,寻找进一步提高玉米产量的途径。【方法】利用图像处理技术采集了10个品种的果穗几何特征,分析了穗粒重对果穗几何特征组合的回归,以及穗粒重与穗大小特征的相关性。矩形度定义为果穗面积占其外接矩形面积的比例,分别与穗长+穗粗、穗面积、穗体积组合建立回归方程。【结果】上述3种组合方程,分别解释了品种间籽粒产量总变异的77.7%、70%和78.7%,矩形度的贡献大于或者约等于穗大小几何特征。同样结构的回归方程在矫正品种产量后,解释了环境间籽粒产量总变异的81.3%—82.0%,矩形度的贡献小于穗大小几何特征。穗大小对籽粒产量的简单决定系数为:在品种间,三种维数的大小特征都不显著;在环境间,穗长、穗粗、穗面积、穗体积分别为0.387、0.167、0.590、0.571。【结论】穗大小单一特征的重要性次序为:穗体积穗面积穗长、穗粗,穗矩形度是反映穗形态的一个重要性状,与穗大小特征相组合,能够高精度预测穗粒重。     

8984×GY220F2∶3家系植株性状的分离特征及相关分析

[目的]研究由优良普通玉米自交系8984与高油玉米自交系GY220杂交构建的F2∶3家系的分离特征及其相关性。[方法]在夏播环境条件下对8个植株性状进行分析。[结果]F2∶3家系间各性状均存在极显著的差异,并呈连续性正态分布,存在明显的双向超亲分离;株高与穗位高、顶高、穗上叶片数、叶面积、雄穗长和雄穗分枝数,穗位高与顶高、穗上叶片数、叶面积、雄穗长和雄穗分枝数,顶高与顶高/株高、穗上叶片数、叶面积、雄穗长和雄穗分枝数,顶高/株高与穗上叶片数,穗上叶片数与叶面积、雄穗分枝数,叶面积与雄穗长间均呈显著或极显著的表型和遗传正相关;顶高/株高与株高、穗位高、叶面积和雄穗分枝数间均呈显著或极显著的表型和遗传负相关。[结论]该研究可以为高油玉米育种及其相关性状的分子遗传研究提供一定的科学依据。     

广西主栽玉米品种氮胁迫能力鉴定

【目的】鉴定广西主栽玉米品种的耐低氮能力,筛选适合广西种植的耐低氮型玉米品种,为当地山区玉米生产提供参考。【方法】采用裂区设计,以施氮量为主处理、品种为副处理进行10个主栽玉米品种氮胁迫试验。主处理设正常施氮(N 180 kg/ha,CK)与氮胁迫(N 0 kg/ha)2个处理,灌浆期测量株高与穗位高,成熟期测产并调查穗部性状。分析各玉米品种主要农艺性状指标的耐低氮指数差异性及相关性,并采用模糊函数法五级制划分标准对各玉米品种的耐低氮能力进行综合评价。【结果】氮胁迫处理的株高、穗位、穗长、穗行、穗粒数、百粒重和产量均低于CK,果穗秃尖长则较CK长。不同玉米品种在氮胁迫下各性状的耐低氮指数存在差异,其中以产量的耐低氮指数最小,氮胁迫对其影响最大;株高、穗长、穗行、百粒重等性状的耐低氮指数差异不明显;秃尖长的耐低氮指数变幅最大。相关性分析结果表明,产量与穗粒数呈极显著正相关(P<0.01),与百粒重呈显著正相关(P<0.05,下同),与秃尖长呈显著负相关;氮胁迫条件下,玉米各性状对产量影响程度排序为穗粒数>百粒重>秃尖长>穗行>穗长>株高>穗位。以模糊函数法对各品种耐低氮能力进行综合评价,结果表明,桂单0810、迪卡008、华优168和桂单162的耐低氮能力较强,先达901、亚航0919、兆丰788、桂单901和正大808种的耐低氮性属于中间类型,瑞特237的耐低氮能力较弱。【结论】产量、穗粒数、百粒重和秃尖长可作为大田生产中快速、简易筛选耐低氮玉米品种的指标;初步筛选出耐低氮能力较强的品种为桂单0810、迪卡008、华优168和桂单162。