东北地区高温对玉米生产的影响及对策

极端高温是制约东北农作区玉米生产的主要气象灾害之一.本文通过研究气候变暖背景下玉米不同生育时期内日最高温度大于30℃的积温(AT)和日最高温度大于30℃的天数(AD)的时空变化特征,分析了极端高温对东北农作区不同地区玉米生产的影响,并探讨了应对高温的对策.结果表明:1961—2010年,东北农作区玉米生育期内温度显著升高,开花期(花前花后20 d)最高温度明显大于其他生育时期,玉米全生育期、营养生长期(播种到开花前11 d)、花期和生育后期(开花后11 d到收获)4个时期日最高温度的气候趋向率分别为0.16、0.14、0.06和0.23℃·10 a-1.近50年东北农作区玉米全生育期AT明显增加,西南部地区的AT明显高于其他区域,营养生长期AT的增加趋势明显大于其他两个时期.玉米全生育期AD明显增加,高值区也主要集中在西南部地区,生育后期的AD的增加趋势大于其他两个生育时期.东北农作区玉米生育期内极端高温显著影响玉米生产,其中营养生长期的极端高温对玉米产量的不利影响十分显著,松辽平原地区玉米生产的高温风险明显大于其他地区.优化作物布局,培育耐高温品种,调整玉米生产管理措施,构建防灾减灾玉米生产体系是东北农作区玉米生产应对高温风险的有效措施.     

温度和食料对白眉野草螟幼虫生长发育的影响

【目的】白眉野草螟Agriphila aeneociliella(Eversmann)是近年在我国小麦上新发现的一种害虫,以幼虫在小麦茎基部取食危害,造成缺苗断垄,对我国小麦的安全生产构成潜在的威胁。本研究旨在明确温度和食料对其生长发育的影响,对该害虫的预测预报和有效防控具有重要的指导意义。【方法】在光周期14L∶10D,RH 70%±5%的条件下,设置系列恒定温度,用小麦作饲料,记录和分析不同温度下幼虫各龄的发育历期、存活率,明确其发育起点温度、有效积温;设置温度25℃,光周期14L∶10D,RH 70%±5%的条件,分别用小麦、玉米和人工饲料饲养,分析不同食料对其生长发育和成活率的影响。【结果】在恒温(13~29℃)范围内,白眉野草螟幼虫发育历期随温度升高而逐渐缩短,存活率没有明显差异;在恒温33℃,该虫不能完成幼虫期生长发育而死亡。不同食料饲养后,幼虫各龄发育历期存在显著差异,顺序为取食小麦取食玉米取食人工饲料,尤其是1-3龄幼虫差异最为明显,取食小麦、玉米的4-6龄幼虫发育历期差异未到达显著水平,但显著低于取食人工饲料的幼虫。【结论】白眉野草螟幼虫具有很强的温度适应能力,不同温度对其发育历期具有显著的影响;在目前白眉野草螟发生危害区的主要粮食作物中,小麦为其最适宜寄主,室内条件下取食玉米也能完成幼虫期的生长发育。本研究为制定白眉野草螟在我国的潜在发生危害区提供了理论数据,为田间种群动态变化的预测预报和综合治理提供了技术支撑。     

亚洲玉米螟发育速率与温度关系研究

利用１０￣３４℃的９个恒温对亚洲玉米螟Ｏｓｔｒｉｎｉａ ｆｕｒｎａｃａｌｉｓ（Ｇｕｅｎｅｅ）发育与温度的关系进行了研究。亚洲玉米晕除了在１０℃不能发育以外,在其８种恒温中均可发育,但其死亡率在１２０℃和３４℃中较高。从产卵成到虫羽化,卵期占整个发育过程中１７％,幼虫期占５７％,蛹期占２５％。最低发育起点温度卵期为１０．３８℃,幼虫期为１０．０６℃,蛹期为１１．０７℃。高温限制温度卵期为２８．００℃     

黄淮海地区夏玉米生长季的干旱风险

干旱是对农业影响最大的农业气象灾害,进行干旱风险评估对于提升区域灾害风险管理和决策水平、减轻农业损失具有重要的指导意义.本文基于自然灾害风险理论,利用黄淮海夏玉米主产区69个站点的气象、夏玉米播种面积和产量数据,以及当地有效灌溉面积等数据,从灾害风险的危险性、脆弱性、暴露性和防灾减灾能力4个方面构建风险评估指标和模型,对黄淮海夏玉米主产区干旱灾害的风险进行评估分析.结果表明: 黄淮海地区夏玉米生长季(6—9月),干旱发生危险性最大的阶段主要是播种-出苗期和乳熟-成熟期,其中,河北中南部、河南西部和北部的危险性最大.经加权叠加脆弱性、暴露性和防灾减灾能力后,夏玉米干旱综合风险最大的地区主要分布在河南西部和西南部部分地区;其次是河南南部、河北沧州、邢台以及山东德州等地,属于次高风险区;风险低值区主要分布在山东南部、安徽北部和河南的信阳等地;其他地区属于中度风险区.     

基于统计和过程模型的河南省夏玉米最适播种期时空分布特征

播种期是影响夏玉米产量的重要因素,研究夏玉米最适播种期的时空分布特征对指导夏玉米生产有重要意义.本文应用统计模型和APSIM Maize过程模型分析了河南省夏玉米最适播种期的时空分布特征.结果表明: 河南省夏玉米的最适播种期为5月30日至6月13日,南早北晚,北部地区以6月4日至13日播种为宜,西部山区应在5月30日左右播种,南部地区应尽量保证在6月8日前播种.晚熟品种‘农大108’应比中熟品种‘丹玉13’至少提前播种2 d,气候变暖背景下若收获期可推迟1周,则最适播种期将至少推迟3 d.在生长季降水偏少年型下,夏玉米应较正常年型晚播7 d左右;而在生长季降水偏多年型下,夏玉米应早播7 d左右.1971—2010年,河南省夏玉米最适播种期变化趋势不显著,但是由于温度变化和品种改良对冬小麦成熟期的影响,导致河南省驻马店以南地区、中部的伊川、内乡、南阳,以及北部的林州和西部的三门峡地区夏玉米可播种期提前,可播种范围扩大.统计方法和APSIM模型计算的夏玉米最适播种期在76.7%的研究站点无显著差异.结合两种方法,北部地区应保证需水关键期降水充足和灌浆期温度适宜,做到“见雨即播”.南部地区在满足上述两个指标的条件下,应在播种期降水达到一定有效值时进行播种,对于南部和偏南部地区,该有效值分别为3.9和8.3 mm.     

黄土高原半干旱区柴胡种植模式

采用大田试验,设计冬小麦收获后复播大豆、大豆套作柴胡(小麦-大豆/柴胡)和冬小麦收获后复播柴胡(小麦-柴胡)及玉米套作柴胡(玉米/柴胡)3种种植模式,探讨黄土高原半干旱区适宜柴胡的"粮药"栽培模式.结果表明:与玉米/柴胡和小麦-柴胡种植模式相比,小麦-大豆/柴胡种植模式经济产量最高,生态效益最好;不同柴胡品种中,万柴胡(原产地温度相对较高)产量最高,左柴胡(原产地温度相对较低)最低,表明柴胡适宜从高温地区引种到低温地区栽培,可提高产量.小麦-大豆/柴胡种植模式为最佳"粮药"栽培模式,其柴胡产量比玉米/柴胡和小麦-柴胡种植模式分别增产11.6%和16.8%.     

发育中玉米胚结合蛋白(BiP)的动态变化及定位

Western blot检测表明,在玉米胚发育过程中结合蛋白(BiP)含量与胚可溶性蛋白含量变化一致,在授粉16d后BiP含量随发育而增加;对热激不敏感.组织化学免疫定位表明,在玉米胚发育的不同时期,BiP主要定位在胚芽端、初生维管组织和糊粉层中,提示胚在构建器官的同时,也为其功能执行准备了条件;热激不影响其定位.     

三叶斑潜蝇发育起点温度和有效积温的研究

不同恒温条件下测定了三叶斑潜蝇Liriomyza trifolii (Burgess)各虫态的发育历期,并用直线回归法计算出各虫态的发育起点温度和有效积温.结果表明,三叶斑潜蝇的历期、发育速率与温度间相关性明显,其卵、幼虫、蛹及全世代发育起点温度分别为9.20℃、10.80℃、6.43℃、8.40℃,有效积温分别为68...     

草地贪夜蛾对不同品种玉米的适应性比较研究

为了解不同玉米品种对草地贪夜蛾生长发育的影响,本文通过比较草地贪夜蛾Spodoptera frugiperda取食2种糯质型玉米(明玉1203和苏玉糯5号)与3种普通玉米(苏玉29、苏玉30和郑单958)后的发育历期、死亡率、蛹重、成虫畸形率、繁殖力与幼虫取食选择率等生物学参数,分析了草地贪夜蛾对不同品种玉米的适应性差异.结果表明:以糯质型玉米饲养的草地贪夜蛾幼虫发育历期与成虫寿命均长于取食普通玉米的个体,而蛹重与单雌产卵量低于取食普通玉米的个体.草地贪夜蛾最高总体死亡率(50.82％)与成虫畸形率(41.38％)均来自于取食糯质型玉米明玉1203处理,而最低总体死亡率(37.29％)与成虫畸形率(12.50％)则分别来自于取食糯质型玉米苏玉糯5号和普通玉米苏玉30处理组.此外,仅6龄幼虫对不同玉米品种的取食偏好性存在显著差异,更倾向于取食普通玉米.综合可见,草地贪夜蛾对普通玉米的适应性好于糯质型玉米,且对糯质型玉米明玉1203的适应性最差.研究结果为所选品种玉米的安全生产与草地贪夜蛾的发生为害评估奠定了研究基础.     

温度对荔枝异形小卷蛾发育和繁殖的影响

荔枝异形小卷蛾的蛀梢为害是珍贵树种格木人工林健康发展的主要限制因子。依据其天然分布和潜在推广区的温度范围设置系列温度梯度,探讨温度对荔枝异形小卷蛾发育和繁殖的综合影响。结果显示,温度对荔枝异形小卷蛾各阶段的发育历期具有显著影响,在研究温度范围内,发育历期随温度升高呈显著地下降趋势,世代历期在18℃时为66.87 d,30℃时降至35.77 d。预蛹和蛹的存活率对温度的响应不敏感,而卵、幼虫、成虫的存活率和世代存活率以及产卵量均随温度升高表现为先上升后下降的变化趋势,且繁殖力对温度的反映较存活率敏感,其存活率和繁殖力在18℃时均最低,分别为41.20%和13.90粒,在27℃时发育最适,分别为83.80%和45.40粒,在30℃时虽有下降,分别为66.00%和32.40粒,但仍高于18℃时,即其对低温较高温敏感。荔枝异形小卷蛾完整世代发育起点温度为5.77℃,所需有效积温为876.76 d℃,其中幼虫发育所需有效积温最高,占整个历期的45.23%,发育速率与温度显著正相关。根据荔枝异形小卷蛾为害方式、发育和繁殖特征分析可知,在低温地区其幼虫期长,但世代数少、存活率和繁殖力低,对寄主植物受害部位的单次为害程度严重;在高温地区则幼虫期短,但世代数多、存活率和繁殖力高,对寄主植物受害部位的单次为害程度低,但更为频繁,持续为害程度高。研究结果对于不同地区选择荔枝异形小卷蛾的防治具有借鉴意义,同时有助于指导格木人工林的合理推广和健康发展。     

Pathways in the emergence of developmental neuroethology: Antecedents to current views of neurobehavioral ontogeny

The historical forces that have contributed to our current views of neurobehavioral development (and thus to the fields of developmental psychobiology and neuroethology) are many and varied. Although similar statements might be made about almost any field of science, it is in particular true of this field, which represents a kind of mongrel discipline derived from at least three major sources (psychology, embryology, and neuroscience) and several more minor ones (including developmental psychology and psychiatry, psychoanalysis, education, zoology, ethology, and sociology). Although I attempt to demonstrate here how each of these sources may have influenced the emergence of a unified field of developmental psychobiology or developmental neuroethology, because the present article represents the first attempt of which I am aware to trace the history of these fields I am certain that there is considerable room for improvement, correction, and revision of the views expressed here. Accordingly, I consider this inaugural effort a kind of reconnaissance intended to trace a necessarily imperfect historic path for others to follow and improve upon. In the final analysis, I will be satisfied if this article only serves to underscore two related points: first is the value derived from historical studies of contemporary issues in development, and the second concerns the extent to which our current ideas and concepts about neurobehavioral development, ideas often considered new and contemporary, were already well known to those who came before us. The first point underscores the arguments expressed in the Introduction that the present must always be reconciled with the past, for the past is never entirely past. The second point returns full circle to an important thought expressed in the opening quotation to this article, namely, that even though our historic predecessors lacked much of the empirical facts available to us they were nonetheless able to attain a surprisingly deep understanding of neurobehavioral ontogeny. © 1992 John Wiley & Sons, Inc.     

Development of fluctuating asymmetry in tail feathers of the barn swallow Hirundo rustica

Fluctuating asymmetry represents usually small, random deviations from symmetry in bilateral morphological characters. The ontogeny of asymmetry in morphological characters may reveal information about developmental processes in a general sense. I studied the development of fluctuating asymmetry in feather characters of the barn swallow Hirundo rustica, that are developed repeatedly during the single annual moult, with the following results. First, the side developing a larger feather was found to be partially biased, as demonstrated by one side consistently developing a larger feather under natural and experimentally induced growth episode events. Second, asymmetric feathers were found to consist of asymmetric daily growth increments, and the size of the increments developing under different environmental conditions were positively correlated. Third, fluctuating asymmetries of feathers developing under different environmental conditions were positively correlated, although the level of asymmetry was larger under adverse environmental conditions. Fourth, individual asymmetries in tail length and growth bar length were unrelated to the duration of the developmental period, although late growth increments were smaller and more symmetric than early increments. These observations suggest that fluctuating asymmetry partially arises as a consequence of a random bias in the feather follicles and differences in environmental conditions during ontogeny of feathers.     

A simple model of the relationship between asymmetry and developmental stability

The relationship between developmental stability and morphological asymmetry is derived under the standard view that structures on each side of an individual develop independently and are normally distributed. I use developmental variance of sizes of parts, V_D, as the converse of developmental stability, and assume that V_D follows a gamma distribution. Repeatability of asymmetry, a measure of how informative asymmetry is about V_D, is quite insensitive to the variance in V_D, for example only reaching 20% when the coefficient of variation of V_D is 100%. The coefficient of variation of asymmetry, CV_FA, also increases very slowly with increasing population variation in V_D. CV_FA values from empirical data are sometimes over 100%, implying that developmental stability is sometimes more variable than any previously studied type of trait. This result suggests that alternatives to this model may be needed.     

The beak of the other finch: coevolution of genetic covariance structure and developmental modularity during adaptive evolution

The link between adaptation and evolutionary change remains the most central and least understood evolutionary problem. Rapid evolution and diversification of avian beaks is a textbook example of such a link, yet the mechanisms that enable beak''s precise adaptation and extensive adaptability are poorly understood. Often observed rapid evolutionary change in beaks is particularly puzzling in light of the neo-Darwinian model that necessitates coordinated changes in developmentally distinct precursors and correspondence between functional and genetic modularity, which should preclude evolutionary diversification. I show that during first 19 generations after colonization of a novel environment, house finches (Carpodacus mexicanus) express an array of distinct, but adaptively equivalent beak morphologies—a result of compensatory developmental interactions between beak length and width in accommodating microevolutionary change in beak depth. Directional selection was largely confined to the elimination of extremes formed by these developmental interactions, while long-term stabilizing selection along a single axis—beak depth—was mirrored in the structure of beak''s additive genetic covariance. These results emphasize three principal points. First, additive genetic covariance structure may represent a historical record of the most recurrent developmental and functional interactions. Second, adaptive equivalence of beak configurations shields genetic and developmental variation in individual components from depletion by natural selection. Third, compensatory developmental interactions among beak components can generate rapid reorganization of beak morphology under novel conditions and thus greatly facilitate both the evolution of precise adaptation and extensive diversification, thereby linking adaptation and adaptability in this classic example of Darwinian evolution.     

Linear and threshold-dependent expression of secondary sexual traits in the same individual: insights from a horned beetle (Coleoptera: Scarabaeidae)

Elaborate horns or horn‐like structures in male scarab beetles commonly scale with body size either (a) in a linear fashion with horn size increasing relatively faster than body size or (b) in a threshold‐dependent, sigmoid fashion; that is, males smaller than a certain critical body size develop no or only rudimentary horns, whereas males larger than the threshold size express fully developed horns. The development of linear vs. sigmoid scaling relationships is thought to require fundamentally different regulatory mechanisms. Here we show that such disparate regulatory mechanisms may co‐occur in the same individual. Large males of the south‐east Asian Onthophagus (Proagoderus) watanabei (Ochi & Kon) (Scarabaeidae, Onthophagini) develop a pair of long, curved head horns as well as a single thoracic horn. We show that unlike paired head horns in a large number of Onthophagus species, in O. watanabei the relationship between head horns and body size is best explained by a linear model. Large males develop disproportionately longer horns than small males, but the difference in relative horn sizes across the range of body sizes is small compared to other Onthophagus species. However, the scaling relationship between the thoracic horn and body size is best explained by a strongly sigmoid model. Only males above a certain body size threshold express a thoracic horn and males smaller than this threshold express no horn at all. We found a significant positive correlation between head and thoracic horn length residuals, contrary to what would be expected if a resource allocation tradeoff during larval development would influence the length of both horn types. Our results suggest that the scaling relationship between body size and horn length, and the developmental regulation underlying these scaling relationships, may be quite different for different horns, even though these horns may develop in the same individual. We discuss our results in the context of the developmental biology of secondary sexual traits in beetles. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 83 , 473–480.     

Effects of the egg incubation environment on turtle carapace development

Developing organisms are often exposed to fluctuating environments that destabilize tissue-scale processes and induce abnormal phenotypes. This might be common in species that lay eggs in the external environment and with little parental care, such as many reptiles. In turtles, morphological development has provided striking examples of abnormal phenotypic patterns, though the influence of the environment remains unclear. To this end, we compared fluctuating asymmetry, as a proxy for developmental instability, in turtle hatchlings incubated in controlled laboratory and unstable natural conditions. Wild and laboratory hatchlings featured similar proportions of supernumerary scales (scutes) on the dorsal shell (carapace). Such abnormal scutes likely elevated shape asymmetry, which was highest in natural nests. Moreover, we tested the hypothesis that hot and dry environments cause abnormal scute formation by subjecting eggs to a range of hydric and thermal laboratory incubation regimes. Shape asymmetry was similar in hatchlings incubated at five constant temperatures (26–30°C). A hot (30°C) and severely Dry substrate yielded smaller hatchlings but scutes were not overtly affected. Our study suggests that changing nest environments contribute to fluctuating asymmetry in egg-laying reptiles, while clarifying the conditions at which turtle shell development remains buffered from the external environment.     

红颈常室茧蜂蛹发育的形态特征

红颈常室茧蜂Peristenus spretus Chen et van Achterberg是一种绿盲蝽若虫的优势内寄生蜂,本研究利用超景深三维显微系统、显微镜观察了红颈常室茧蜂老熟幼虫发育特征、蛹形态特征及蛹发育后期卵巢的超微结构。结果表明:红颈常室茧蜂蛹期为12～15 d,其中雌蛹期比雄蛹期长2～3 d。根据其形态特征,可将蛹划分为预蛹期、第一蛹阶段、第二蛹阶段、第三蛹阶段。蛹期发育前9 d,蛹期组织结构开始分化形成,成蜂的外部形态基本显现,但性别难以区分;蛹期发育至10～14 d,可通过幼蜂体表颜色的变化或腹部末端的形状区分性别,在相同的适宜温度条件下,雌蜂比雄蜂颜色深,雌蜂腹部末端比较尖,有突出的产卵瓣,雄峰腹部末端钝圆,无凸起;雌蜂卵巢在化蛹后的第11天开始形成,卵巢初期的形状如细丝,此时卵巢管已开始初步分化,但卵室尚未分化;蛹发育至第12天时,卵巢管逐渐加粗,卵室开始分化;第13天时,卵巢管、卵室数量逐渐增多;第14天卵巢基部开始有少量成熟卵子产生,呈乳白色。10～12 d,雄蜂腹部末端绒毛逐渐增多,体壁变硬,逐渐角质化,虫体可活动,雄蜂胸部略带黑色,翅逐渐伸展开,整个虫体呈浅红棕色。本研究结果明确了红颈常室茧蜂蛹发育的形态变化过程,提出了蛹期雌雄区分的方法,叙述了蛹后期卵巢发育特征,为研究该蜂繁殖机理奠定了形态学基础。