干旱对东北春玉米生长发育和产量的影响

选取玉米品种丹玉39为供试材料,利用大型农田水分控制试验场,采用大田池栽方式,在玉米三叶-拔节期、拔节-吐丝期、吐丝-乳熟期分别开展中度干旱胁迫及复水控制对比试验,分析3个关键生育时期干旱胁迫对春玉米生长发育和产量的影响.结果表明：与水分适宜对照（CK）相比,三叶-拔节期遭受干旱胁迫后,全生育期推迟13 d,至拔节普遍期,株高偏低29.8%,叶面积偏小41.2%,复水后,株高和产量得到较大程度恢复,果穗性状和最终产量差异不大;拔节-吐丝期遭受干旱胁迫后,全生育期缩短7 d,至吐丝普遍期,株高偏低18.6%,叶面积偏小14.1%,果穗长、穗粒数、果穗干质量、穗粒质量分别下降6.9%、19.1%、28.1%和29.4%,空秆率增加13.3%;吐丝-乳熟期遭受干旱胁迫后,全生育期缩短15 d,生长至乳熟普遍期,株高偏低2.3%,叶面积偏小37.3%,果穗长、穗粒数、果穗干质量、穗粒质量分别下降9.2%、24.1%、30.8%和27.9%,空秆率增加24.5%.拔节-吐丝期、吐丝-乳熟期干旱胁迫处理并复水后,玉米株高恢复不明显,产量降幅显著.     

中国骨干玉米自交系抗旱性分析与评价

在新疆典型干旱、半干旱地区,通过玉米自交系的14个主要产量性状对干旱胁迫的响应特征进行分析,用主成分分析法筛选其抗旱性的主要鉴定指标,并采用抗旱系数和抗旱指数对自交系的抗旱性进行聚类分析,综合评价47份自交系的抗旱性。结果显示:(1)干旱导致玉米自交系株高、穗位高、叶绿素含量降低,果穗短小,秃尖增大,穗行数和行粒数减小,千粒重和穗粒重降低,最终造成产量下降。(2)各自交系抗旱性强弱与干旱条件下的穗粒重、穗粗、行粒数、千粒重、株高、穗位高、穗长、秃尖长、穗行数、叶绿素含量等性状具有较密切的关系,其中抗旱性表现较好的自交系是掖52106、英64、478等,其次是Mo17Ht、Mo17、丹340、郑58、X178、C103等。研究表明,在育种实践中,田间自交系抗旱性筛选应以穗粒重、穗粗、行粒数、千粒重、株高、穗位高、穗长、秃尖长、穗行数、叶绿素含量等为主要指标,并结合产量抗旱系数、抗旱指数对自交系抗旱性进行综合评价。     

玉米果穗秃顶的防治

玉米果穗成熟后,常常可见秃顶和缺粒,使穗粒数减少。发生这种现象的主要原因是由于雌穗开花顺序不同而引起的。玉米雌穗吐丝的顺序是穗长基部1/3处的花丝首先伸出苞叶,然后上下同时向外伸出(如图)。穗顶部的花丝抽出最晚,其次是穗基部。当顶部和基部的花丝抽出时,往往已是大田植株散粉的末期了,粉     

干旱对东北春玉米生长发育和产量的影响

选取玉米品种丹玉39为供试材料,利用大型农田水分控制试验场,采用大田池栽方式,在玉米三叶-拔节期、拔节-吐丝期、吐丝-乳熟期分别开展中度干旱胁迫及复水控制对比试验,分析3个关键生育时期干旱胁迫对春玉米生长发育和产量的影响.结果表明:与水分适宜对照(CK)相比,三叶-拔节期遭受干旱胁迫后,全生育期推迟13 d,至拔节普遍期,株高偏低29.8％,叶面积偏小41.2％,复水后,株高和产量得到较大程度恢复,果穗性状和最终产量差异不大;拔节-吐丝期遭受干旱胁迫后,全生育期缩短7d,至吐丝普遍期,株高偏低18.6％,叶面积偏小14.1％,果穗长、穗粒数、果穗干质量、穗粒质量分别下降6.9％、19.1％、28.1％和29.4％,空秆率增加13.3％;吐丝-乳熟期遭受干旱胁迫后,全生育期缩短15 d,生长至乳熟普遍期,株高偏低2.3％,叶面积偏小37.3％,果穗长、穗粒数、果穗干质量、穗粒质量分别下降9.2％、24.1％、30.8％和27.9％,空秆率增加24.5％.拔节-吐丝期、吐丝-乳熟期干旱胁迫处理并复水后,玉米株高恢复不明显,产量降幅显著.     

玉米开花期相关性状的QTL分析

利用玉米强优势组合(Mo17×黄早四)自交衍生的191个F_2单株构建了由SSR和AFLP标记组成的分子连锁图谱,用F2进一步自交产生的184个F_(2:3)家系调查散粉期、吐丝期和开花-吐丝间隔期(ASI)的表型值,采用基于混合线性模型的复合区间作图法和相应的作图软件QTLmapper/V2.0,在两个生长环境下定位了与散粉期、吐丝期和ASI相关的QTL数目分别为13、7和5个,检测到3对控制散粉期、17对控制吐丝期和5对控制ASI的上位性效应位点;同时发现了与环境存在显著互作的3个散粉期、3个吐丝期和2个ASI单位点标记区域以及1对散粉期、3对吐丝期和2对ASI上位性效应区域.对玉米散粉期、吐丝期和ASI遗传基础中遗传因素相对作用大小分析表明,加性效应、部分显性效应和上位性效应是玉米开花期相关性状的重要遗传基础.     

基于相对叶绿素含量的玉米自交系氮敏感性鉴定与评价

氮敏感性鉴定与评价是培育耐低氮与氮高效利用玉米品种的重要的研究内容。本研究采用前期建立的快速无损伤测定SPAD值分析相对叶绿素含量的模型,于低氮与正常供氮大田试验处理下,对我国玉米育种与生产上重要的 189 份玉米自交系开展了低氮与正常供氮条件下不同时期与不同部位叶片的相对叶绿素含量分析。方差分析结果表明,低氮与正常供氮条件下,叶绿素含量均存在极显著的基因型与环境差异,基因型差异是氮敏感性差异的重要原因之一。开花期和开花后10天玉米主要功能叶穗三叶(穗位上第1叶、穗位叶、穗位下第1叶)叶绿素含量之间具有极显著正相关;大喇叭口期玉米全展叶叶绿素含量与各时期各部位叶绿素含量之间呈现极显著中度相关。将正常供氮条件下的性状值与低氮胁迫下性状值的差值占正常供氮条件下性状值的百分比定义为氮敏感性。189份玉米自交系氮平均氮敏感指数变幅为23.86%- 36.00%,表现高度耐低氮的材料有合344和昌7-2等40份自交系,高度敏感的材料有CML206和CA375等40份自交系。本研究提供了一种快速高效的种质资源氮敏感性鉴定与评价方法,并为玉米耐低氮与氮高效育种的遗传育种提供了重要分析结果与基础数据。     

表油菜素内酯对玉米果穗发育的影响（简报）

在玉米雌穗小穗和小花分化期,全株喷施0.01 ppm表油莱素内酯(BR)能促进幼穗发育,使幼穗的生长速度加快、吐丝提前,籽粒的败育率减少,从而导致玉米产量的提高。     

遮阴和种植密度对东北春玉米穗部发育和植株生产力的影响

探讨遮阴对玉米穗部特性的影响及其产量效应,可以为应对气候变化与密植栽培条件下的玉米品种选育和高产栽培提供参考依据.本研究选用2个品种(紧凑型‘中单909’、平展型‘内单4’)和2个种植密度(4.5、9.0万株·hm^-2),在吉林省公主岭市开展田间遮阴试验,设置遮阴(遮阴度65%,小喇叭口期-成熟期)和不遮阴(对照)2个处理,研究遮阴和种植密度对不同株型玉米的穗部发育和植株生产力的影响.结果表明: 遮阴显著影响春玉米雌穗发育,造成散粉和吐丝期推迟,导致散粉吐丝间隔期延长3～15 d;遮阴显著降低春玉米干物质积累,籽粒产量下降50%以上(50.8%～87.0%);密植条件下春玉米穗部特性和产量性能受遮阴的影响显著高于稀植栽培;不同玉米品种相比,紧凑型品种的穗部特性和产量受遮阴和种植密度的影响低于平展型品种,紧凑型品种对生态环境变化的适应性较强,耐阴性和耐密性表现出一致性.     

二重雌雄异型异熟物种色木槭3种表型花的细胞形态学研究

二重雌雄异型异熟,即雌雄功能按雄-雌-雄顺序分别表达,是有花植物中较为少见的异熟机制.槭属(Acer)大部分物种具有二重雌雄异型异熟的开花物候,且第一期雄花与第二期在形态上差别较大.为深入探讨花发育模式对花形态和开花物候的影响,本文应用石蜡切片技术和光镜技术,对色木槭(Acer mono)各个发育时期的3种类型花(雄花...     

玉米自交系×大刍草远缘杂交后代性状变异研究初探

采用人工剥苞多次授粉方法,将近缘一年生二倍体类玉米（大刍草）与普通玉米自交系杂交,对F1、F2以及回交后代B1的抽雄期、吐丝期、散粉期、株高、穗位高、分蘖进行调查研究,分析远缘杂交后代农艺性孳的遗传变化。结果表明,远缘杂交后代株高、穗化高分离变异较大,而抽雄期、吐丝期、散粉期分离变异较小,不同世代植株分蘖变化较大,F1代有57．5％植株、F2代有23％植株、BC1F1代有0．8％植株有分蘖;雌穗光周期敏感性大于雄穗。     

Identification of quantitative trait loci under drought conditions in tropical maize. 1. Flowering parameters and the anthesis-silking interval

Drought is an important climatic phenomenon which, after soil infertility, ranks as the second most severe limitation to maize production in developing countries. When drought stress occurs just before or during the flowering period, a delay in silking is observed, resulting in an increase in the length of the anthesis-silking interval (ASI) and in a decrease in grain yield. Selection for reduced ASI in tropical open-pollinated varieties has been shown to be correlated with improved yields under drought stress. Since efficient selection for drought tolerance requires carefully managed experimental conditions, molecular markers were used to identify the genomic segments responsible for the expression of ASI, with the final aim of developing marker-assisted selection (MAS) strategies. An F₂population of 234 individuals was genotyped at 142 loci and F₃ families were evaluated in the field under several water regimes for male flowering (MFLW), male sterility (STER), female flowering (FFLW) and ASI. The genetic variance of ASI increased as a function of the stress intensity, and the broad-sense heritabilites of MFLW, FFLW and ASI were high under stress conditions, being 86%, 82% and 78%, respectively. Putative quantitative trait loci (QTLs) involved in the expression of MFLW and/or FFLW under drought were detected on chromosomes 1, 2, 4, 5, 8, 9 and 10, accounting for around 48% of the phenotypic variance for both traits. For ASI, six putative QTLs were identified under drought on chromosomes 1, 2, 5, 6, 8 and 10, and together accounted for approximately 47% of the phenotypic variance. Under water stress conditions, four QTLs were common for the expression of MFLW and FFLW, one for the expression of ASI and MFLW, and four for the expression of ASI and FFLW. The number of common QTLs for two traits was related to the level of linear correlation between these two traits. Segregation for ASI was found to be transgressive with the drought-susceptible parent contributing alleles for reduced ASI (4 days) at two QTL positions. Alleles contributed by the resistant line at the other four QTLs were responsible for a 7-day reduction of ASI. These four QTLs represented around 9% of the linkage map, and were stable over years and stress levels. It is argued that MAS based on ASI QTLs should be a powerful tool for improving drought tolerance of tropical maize inbred lines.     

玉米雌雄开花间隔天数、结穗率与产量的数量性状位点(QTL)分析

采用SSR标记连锁图谱和复合区间作图法在山西灌溉和干旱胁迫条件下,对玉米(Zea mays L.)自交系黄早四×掖107组合的F3群体雌雄开花间隔天数(ASI)、结穗率和籽粒产量进行了数量性状位点(QTL)定位及基因效应分析.结果表明,在两种水分处理下,ASI、结穗率与籽粒产量的相关性均达到显著水平(P＜0.05).在灌溉和干旱胁迫下,分别检测到3个和2个控制ASI的QTL,位于第1、2、3和第2、5染色体上.在灌溉条件下,在第3和第6染色体上各检测到1个控制结穗率的QTL,基因作用方式呈加性或部分显性,可解释19.9%的表型变异;在干旱条件下,在第3、 7、10染色体上共检测到4个控制结穗率的QTL,基因作用方式为显性或部分显性,可解释60.4%的表型变异.在灌溉和干旱胁迫下,控制产量的QTL分别定位在第3、6、7和第1、2、4、8染色体上,基因作用方式均以加性或部分显性为主,可解释的表型变异为7.3%～22.0%.在干旱条件下,借助连锁分子标记和基因效应分析,可构建包含ASI、结穗率和产量QTL的选择指数,用于分子标记辅助育种.     

新疆自然高温环境下玉米自交系开花期耐热性鉴定与评价

在新疆夏季自然高温环境下,以田间玉米空秆率、果穗结实率、相对结实率为主要评价指标,综合籽粒产量与穗部性状,对26份国内外玉米骨干自交系连续2年进行耐热性鉴定与评价,结合新疆当地高温干燥的气候特点,建立一套适宜玉米种质资源大田耐热性的鉴定、评价体系,为中国玉米耐热种质资源的遗传改良和新品种选育提供参考。结果表明:(1)不同基因型玉米自交系空秆率、果穗结穗率、相对结实率和耐热性差异较大,其中GW5F、GW4F、GW7F和PH6WC耐热性最强,在高温胁迫下空秆率最低,果穗结实率与相对结实率最高;其次为PHBA6、新自351等8份自交系,在高温胁迫下籽粒产量及综合表现较好;其余自交系对高温均表现敏感。(2)高温胁迫导致玉米穗部性状严重衰退,其中的穗重、穗行数和行粒数所受影响最大。(3)在年份或材料之间,玉米自交系籽粒产量与其主要农艺性状相关性差异较大,并以果穗重与籽粒产量相关性最高。(4)以相对结实率为主要指标通过层次聚类可将参试材料分为两大群,耐热性最强的GW5F、PH6WC、GW4M聚为第Ⅰ群,其余自交系聚为第Ⅱ群;第Ⅱ群中‘吉63’、Mo17等6份自交系可聚为第1亚群,PHBA6、LH82等6份自交系聚为第2亚群,郑58、新农育6390M等11份自交系聚为第3亚群。综合分析来看,该研究中表现极耐高温的4份自交系均为国外优异种质,可用于玉米耐高温基础研究和遗传改良;表现较强耐热性的8份品系多来自于新疆本地选育的材料,其遗传基础较为广泛,适应当地的高温环境,也是优异的耐热育种资源。     

A single point mutation in Ms44 results in dominant male sterility and improves nitrogen use efficiency in maize

Application of nitrogen fertilizer in the past 50 years has resulted in significant increases in crop yields. However, loss of nitrogen from crop fields has been associated with negative impacts on the environment. Developing maize hybrids with improved nitrogen use efficiency is a cost‐effective strategy for increasing yield sustainably. We report that a dominant male‐sterile mutant Ms44 encodes a lipid transfer protein which is expressed specifically in the tapetum. A single amino acid change from alanine to threonine at the signal peptide cleavage site of the Ms44 protein abolished protein processing and impeded the secretion of protein from tapetal cells into the locule, resulting in dominant male sterility. While the total nitrogen (N) content in plants was not changed, Ms44 male‐sterile plants reduced tassel growth and improved ear growth by partitioning more nitrogen to the ear, resulting in a 9.6% increase in kernel number. Hybrids carrying the Ms44 allele demonstrated a 4%–8.5% yield advantage when N is limiting, 1.7% yield advantage under drought and 0.9% yield advantage under optimal growth conditions relative to the yield of wild type. Furthermore, we have developed an Ms44 maintainer line for fertility restoration, male‐sterile inbred seed increase and hybrid seed production. This study reveals that protein secretion from the tapetum into the locule is critical for pollen development and demonstrates that a reduction in competition between tassel and ear by male sterility improves grain yield under low‐nitrogen conditions in maize.     

两个相关基因表达量和SNP与玉米雄穗大小相关

玉米雄穗通常较发达,散粉量大于授粉需要,过量消耗能量会影响光合产物向果穗的分配,过于发达的雄穗还会影响群体透光性、降低光合效率。生产实践和育种研究证明,由于雄穗大小与玉米籽粒产量负相关,因此成为品种选育的间接选择指标。该研究根据前人的报道,从11个雄穗大小不同的玉米自交系中扩增角蛋白相关蛋白基因KAP5-4和受体样蛋白激酶基因CLV1的基因组序列,多重比较后用以分析其开放阅读框、保守结构和单核苷酸多态性,用荧光实时定量PCR检测其在雄穗原基中的差异表达,并与雄穗分枝数和雄穗干重两个度量雄穗小的指标进行了相关分析。结果表明:KAP5-4基因的相对表达量与雄穗分枝数(r=0.77,P0.01)和雄穗干重正相关(r=0.83,P0.01)。11个自交系的CLV1基因开放框在2 104 bp存在单核苷酸多态性,其中5个自交系的2 014~2 016 bp核苷酸组成密码子GAC,编码受体样蛋白第702位酸性的天冬氨酸,另6个自交系的2 014~2 016 bp核苷酸组成密码子AAC,编码受体样蛋白第702位极性天冬氨酰胺。在前5个自交系中,CLV1基因的相对表达量与雄穗分枝数(r=-0.92,P0.01)和雄穗干重(r=-0.91,P0.05)负相关;而在后6个自交系中,仅与雄穗干重负相关(r=-0.91,P0.05)。综上所述,KAP5-4和CLV1基因的表达和单核苷酸多态性与玉米雄穗大小关系密切,可开发功能性的DNA标记用于玉米育种的分子标记辅助选择。     

干旱下接种根际促生细菌对苹果实生苗光合和生理生态特性的影响

本试验研究了接种根际促生细菌(PGPR)对干旱条件下植物光合和生理生态特性的影响,以期为PGPR在植物抗旱中的应用提供理论依据.采用盆栽试验,以苹果实生幼苗为供试植物,以经过筛选得到的既具有1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性又具有较强溶磷能力的根际促生菌YX₂为供试菌株,设置正常水分(CK)、轻度干旱(LD)、中度干旱(MD)和重度干旱(SD),其相应含水量分别为田间持水量的70%～80%、55%～65%、40%～50%、25%～35%,研究不同程度干旱胁迫条件下接种YX₂对苹果实生幼苗光合和生理生态特性的影响.结果表明: 与未接种处理相比,干旱环境下接种YX₂提高了苹果幼苗叶片的相对含水量、叶绿素含量、抗氧化酶活性、叶绿素荧光值、气孔导度和光合性能,降低了相对电导率、渗透调节物质和丙二醛的积累,缓解了干旱胁迫对净光合速率的抑制,增强了抗氧化系统的防御能力,减少了细胞膜过氧化伤害,提高了植株抗旱性能.     

Effect of environment on the early steps of ear initiation in maize (Zea mays L.)

The effects of environmental conditions on ear-shoot initiation have been investigated in three inbred genotypes of Zea mays L. which are used for seed production. Scanning electron microscopy (SEM) and binocular examination during the vegetative phase showed that axillary meristems are initiated at the same rate as the leaf primordia on the apical meristem, but with a delay of 5.6–7.0 plastochrons, depending on the genotype. Furthermore, the topmost axillary meristem is initiated on the same day as the tassel, whatever the genotype. One of the inbreds (B22) used in this study has been reported to exhibit, in field conditions, a reproductive failure affecting car initiation, causing the topmost car to be replaced at maturity by a sterile, leaf-like, structure. Scanning electron microscopic study of the formation of the abnormal axillary buds indicated that ear failure resulted from the early collapse of the axillary meristem followed by elongation of the prophyll or of the meristem itself. Using controlled environments, ear abortion was mimicked by a chilling treatment (10°C), given just before tassel initiation. Other factors, such as high irradiance and flooding, enhanced the abortive response. The critical stage for the main car was just before the initiation of the topmost axillary meristem which also corresponded to tassel initiation. Chilling the plants before or after tassel initiation either induced an acclimation response or had no effect. The three inbreds showed differential responses to the stress treatment, indicating that a genetic factor is implicated as well. It is suggested that chilling causes a perturbation of apical dominance which, in the responsive genotypes, represses axillary meristem development. The use of a stress-sensitive inbred such as B22 as a model system could yield some interesting clues to the mechanism of endogenous control of ear initiation in maize.     

迷迭香对干旱胁迫的生理响应及其诱导挥发性有机化合物的释放

为探讨干旱胁迫对迷迭香(Rosmarinus officinalis)生理生化特性及挥发性有机化合物(VOC)释放规律的影响, 该文采用盆栽称重控水法研究了轻度(LD)、中度(MD)和重度(SD)干旱胁迫对迷迭香二年生实生苗叶片细胞膜透性、可溶性糖、可溶性蛋白质和丙二醛(MDA)含量以及脂氧合酶和抗氧化保护酶活性的影响, 并采用热脱附/气相色谱/质谱联用技术对不同干旱胁迫下迷迭香释放的挥发性有机化合物成分进行了分析。结果表明: 干旱胁迫对迷迭香叶片可溶性糖和可溶性蛋白质含量有明显的影响, MD和SD处理12天时其含量极显著地增加(p < 0.01), 与对照相比可溶性糖分别增加了51.5%和87.4%, 可溶性蛋白质含量分别增加了0.82和1.40倍。在MD和SD胁迫下, 超氧化物歧化酶、过氧化物酶和过氧化氢酶对干旱胁迫的响应存在一定差异, 表现为相互协调的作用。随着干旱胁迫时间的延长, 迷迭香体内MDA含量极显著地增加(p < 0.01), 细胞膜损伤率显著增加。分析显示, 迷迭香释放的VOC主要是萜烯类化合物, 占总量的46.0%以上; 随着干旱胁迫增强, 迷迭香释放的VOCs总量减少, 种类增多; LD、MD和SD胁迫处理萜烯类化合物相对含量与对照相比分别增加了14.4%、17.0%和23.7%; 干旱胁迫还明显诱导绿叶挥发物(green leaf volatiles)和醛类化合物的释放, 诱导产生了2-己烯醛、叶醇、山梨醛和癸醛4种新组分。研究表明: 干旱胁迫条件下, 迷迭香能够通过调节保护酶活性、渗透调节物质含量和释放VOCs来提高抗旱性。