不同生态下云南稻核心种质孕穗期耐冷性状的表型多样性差异

以504份云南地方稻核心种质为材料,在昆明自然低温平均18℃(冷害)和新平27℃(正常)条件下进行孕穗期耐冷性状的表犁多样性生态差异分析.结果表明:(1)在3种生态环境下,云南稻核心种质11个耐冷性状的平均值、标准差、变异系数等参数存在一定差异,总趋势呈现籼稻(Indica)不同环境间这3个特征值差异较粳稻(Japonica)明显;弱耐冷系统群差异较强耐冷系统群明显.(2)不同环境间11个耐冷性状Shannon-weaver遗传多样性指数存在明显差异,体现为正常环境高于冷害环境,粳稻(Japonica)高于籼稻(Indica),强耐冷材料高于弱耐冷材料.这种差异主要由剑叶长、穗颈长、穗下节长、1～2节长、穗长、主穗实粒数和结实率等7个耐冷性状差异所致.     

云南粳稻核心种质杂种后代孕穗期耐冷性研究

以236份云南地方粳稻核心种质和云南主栽梗稻Oryza satica品种合系35配制的杂种F5、BC1F4、BC2F3和BC3F2为材料,在昆明自然低温平均17.8℃(冷害)条件下,对亲本及其后代进行孕穗期耐冷性研究.结果表明:①亲本耐冷性状间的相关性明显高于其杂种后代,不同世代间总体趋势为随着回交世代增加其性状间相关性减弱.在亲本及其杂种后代间耐冷指标性状穗颈长、穗下节长、每穗实粒数、每穗秕粒数与结实率均呈较高的(≥0.370)极显著(n=236,R0.01=0.181)相关.②株高、穗颈长、穗下节长等耐冷性状在亲本强弱耐冷系统群间的差异明显,表现为亲本耐冷性强的材料秆和穗较长、穗粒数较多,同一性状变异程度减小.但随着回交代数的增加,这些性状的平均值逐渐趋同于轮回亲本,差异减小.③穗颈长、穗下节长、每穗实粒数、每穗秕粒数与结实率在5个稻作区间的变化规律呈现一致性,亲本和F5的差异较大,而BC2F4、BC2F3和BC3F2的差异较小,且趋同于轮回亲本.通过连续回交,在BC3F1即可获得耐冷性状表现良好的材料.     

不同种源地云南稻核心种质主要形态性状的遗传特征

揭示云南稻核心种质资源特性、遗传变异特点,对资源的合理利用,指导育种工作,具有重要的意义.以541份云南稻核心种质为材料,在昆明地区生态条件下对其11个形态性状的遗传参数进行研究.结果表明:所研究的11个形态性状广义遗传力在65?%之间,穗颈长、实粒数、秕粒数和结实率的遗传力最大,且均表现出较大的遗传变异,选择潜力较大; 同一性状的遗传差异籼粳间不明显,而稻作区间则存在一定差异.利用本群体进行新品种选育时,应考虑各形态性状的表现特点和遗传潜力大小.对穗颈长、实粒数和结实率系统选育时,滇中一季籼稻粳稻区、滇南单双季籼稻区和南部边缘水陆稻区3个稻作区的材料选择效果较好.     

低磷胁迫下云南稻形态性状的氮肥反应

采用盆栽试验每份材料栽2桶,每盆装4 kg低磷酸性红壤(速效磷2.53 mg·kg-1、速效氮156.7 mg·kg-1和pH=6.03),设置不施氮肥(速效氮156.7 mg·kg-1)和施氮肥(速效氮490.0 mg·kg-1)两种处理对539份云南稻核心种质17个形态性状及其相对指标,研究低磷胁迫下云南稻形态性状的氮肥效应结果表明:总体上低磷胁迫下云南稻核心种质籼稻氮效反应明显比粳稻敏感;按氮反应相对指标将云南稻种17形态性状划分为氮反应的强敏感、中敏感、弱敏感和不敏感型四种类型;揭示了低磷胁迫下云南稻种氮高效鉴定指标以相对穗干质量和相对总干质量为主,相对穗长、秆干质量、地上干质量、根干质量和茎蘖数可作为参考指标,其中穗干质量为氮反应的强敏感型,总干质量、地上干质量、秆干质量和茎蘖数属中敏感型,根干质量属弱敏感型和穗长属不敏感型.另外,低磷胁迫下云南稻种8个对氮反应敏感相对性状无论是在539份云南稻核心种质及其籼粳亚种间,还是在五个稻作区间总趋势是一致的;既证实了该文提出的低磷胁迫下8个氮反应敏感指标性状是十分可靠的,又揭示了低磷胁迫下5大稻作区氮反应的生态差异和土攘类型多样性是云南成为亚洲栽培稻籼粳分化中心之一的驱动力.     

云南稻核心种质耐低磷性状与籼粳亚种间的关系

在土壤有效磷含量6．26mg／kg和40mg／kg条件下对548份云南地方稻核心种质进行形态性状与籼粳亚种鉴别性状间的耐低磷特性研究．以明确籼粳亚种及其中间型耐低磷特性有无明显差异以及耐低磷特性和籼粳分化相互关系。结果表明：（1）相对分蘖力、相对有效穗、相对总干物质量和相对地下干物质量4个耐低磷指标性状可作为水稻耐低磷能力强弱评价的理想指标；低磷胁迫下耐低磷指标性状可作为水稻磷高效基因型筛选指标。（2）云南稻核心种质由95份籼、178份偏籼、85份偏粳和190份粳稻组成．籼粳亚种间平均耐低磷能力存在明显差异：相对分蘖力、有效穗、地下干物质量、总干物质量平均值由大到小依次为籼、偏籼、偏粳、粳．耐低磷能力随程氏指数的增大，呈现递减趋势。（3）云南稻核心种质6个籼粳分类性状和耐低磷指标性状多数呈显著负相关．耐低磷特性和籼粳分化密切相关。     

云南稻种磷高效特性相关性状的生态差异

云南不仅是世界稻种(Oryza sativa L.)最大的遗传和生态多样性中心之一,也是中国土壤类型最丰富的地区;中国南方和云南耕地65%以上缺乏有效磷,土壤缺磷已成为稻作生产的主要限制因子.该文中,缺磷(速效磷6.26 mg·kg-1)与适磷(速效磷40 mg·kg-1)酸性红壤进行比较,以相对茎蘖数(RTA)、相对总质量(RTB)、相对地上质量(RDWU)和相对地下质量(RDWG)为参数,研究了来自云南省16个州市5个稻作区577份水稻核心种质的磷高效基因型及其生态差异,结果表明:低磷胁迫下云南稻核心种质的相对茎蘖数、相对总质量、相对地上质量和相对地下质量密切相关,这4个性状是水稻磷高效鉴定较可靠和方便的指标,并筛选出10个磷高效品种;磷高效基因型在籼粳间存在较大差异,但丁颖分类性状中的水陆、粘糯间差异较小;水稻磷高效品种广泛分布于5个稻作区和绝大多数州市,特别是磷高效极强品种主要来自云南稻种的遗传多样性中心(思茅、临沧、西双版纳、德宏和文山州)和基因多样性中心(南部边缘水陆兼作区).这些结果有力地支持了水稻磷高效特性与酸性红壤和遗传多样性中心有关,更好地理解水稻磷高效特性的地理生态和遗传多样性机制.     

云南稻核心种质苗期与孕穗期耐冷性特点及关系分析

以544份云南地方稻核心种质为材料,在昆明自然低温(苗期平均5.5～12.3℃,孕穗期平均17.8℃)冷害下,按籼粳、稻作区进行云南稻核心种质苗期耐冷性与孕穗期耐冷性的特点及关系研究.结果表明:(1)苗期耐冷性与孕穗期耐冷性密切相关,苗期耐冷性强的材料表现为孕穗期株高、剑叶长和宽、穗颈长、穗下节长、1～2节长、穗长较长、穗粒数较多,耐冷性较强.通过对苗期耐冷性的严格选择,可以间接获得孕穗期耐冷性较强的材料.(2)苗期和孕穗期耐冷性在籼粳间、稻作区间差异明显.籼粳间均表现为粳稻强于籼稻;稻作区间苗期耐冷性为滇中一季籼粳稻区和滇南单双季籼稻区最强,滇中一季籼粳稻区和滇西北高寒粳稻区孕穗期耐冷性较强,揭示了水稻苗期与穗期耐冷性的形成演化机制存在一致性和差异性.     

云南稻核心种质苗期耐冷性及其地理生态差异

采用Nagamine等(1991)法研究了598份云南稻核心种质在稻作区划间、地州间苗期耐冷性强弱、变异程度及其地理生态差异。结果表明,稻作区划间苗期耐冷强弱差异较大,平均耐冷级别为:I(4.70)>II(4.78)>V(4.79)>III(5.34)>IV(5.36),40份强耐冷种质频率为II(45%)>I(25%)>III(22.5%)>V(5.0%)>IV(2.5%),其变异系数为II(32.22%)>I(31.28%)>V(29.65%)>III(19.66%)>IV(19.59%);揭示了苗期耐冷性与低温胁迫下水稻冬春育秧、冷泉水密切相关,其耐冷基因源是云南南部地区冬季育秧和滇中一带苗期倒春寒长期协同进化的结果;苗期耐冷种质广泛存在于热带、亚热带和温带地区,品种间苗期耐冷差异也明显。云南稻核心种质16个地州平均苗期耐冷强弱差异较大。根据气候、生态、云南稻种多样性及其苗期耐冷性等将云南稻作区划分为重冷害多样性贫乏区、冷害多样性中区和轻冷害区三部分。其中,曲靖、大理、楚雄、昆明和丽江5个地州平均耐冷级别3.65~4.32,0—2级苗期强耐冷种质占27.5%(2.5%~10%)和高海拔冷泉水苗期灌溉,属于重冷害多样性贫乏区;文山、红河、思茅、保山、德宏和临沧6个地州平均耐冷级别4.45~5.40,0—2级苗期耐冷种质占70%(5%~30%)和冬春育秧,属于冷害多样性中区;怒江、玉溪、昭通、迪庆和西双版纳5个地州平均耐冷级别5.05~5.87,0—2级苗期耐冷种质占2.5%(0~2.5%),属于轻冷害多样性扩散区。水稻冬春育秧和高海拔冷泉水灌溉在云南稻核心种质苗期耐冷基因源演化中起了重要作用。     

同源四倍体水稻亲本材料的结实研究

研究了2份二倍体水稻和29份同源四倍体水稻(2n=4x=48)亲本(其中4份低代材料、25份高代材料)在2004年和2005年的结实情况.与二倍体对照相比,同源四倍体材料的花粉育性、结实率均不同程度下降,尤其低代材料的花粉育性(59.6%～65.3%)和结实率(26.8%～33.5%)大幅度降低;但经过选择改良,大多数材料的花粉育性和结实率均不同程度提高.F检验表明,同源四倍体不同品种间各性状均差异显著,说明同源四倍体材料具有很大的改良潜力.从1996年到2005年对部分同源四倍体水稻进行了连续选择改良,并对其结实率进行T检验,结果表明经过9a的选择改良,同源四倍体水稻结实率显著提高.本文还对同源四倍体水稻各性状间的相关性进行了分析,结果表明,结实率与花粉育性、穗着粒数、穗实粒数极显著相关,理论产量与花粉育性、有效穗数、穗着粒数、穗实粒数、结实率及千粒重极显著相关.表3图1参18     

云南籼稻核心种质回交后代苗期耐冷性研究

早春低温和连续阴雨是导致籼稻烂秧的主要因素之一,筛选耐冷的种质资源,将耐冷性基因导入高产的籼稻品种之中是防止低温冷害最为经济有效的方法。加强籼籼稻杂交后代的苗期耐冷性研究,可为籼稻耐冷性育种提供条件。以235份云南籼稻核心种质和云南主栽籼稻品种滇屯502(Oryzasatica)配制的杂种F5、BC1F4、BC2F3和BC3F2代为材料,在昆明自然条件下,对亲本及其后代进行苗期(三叶)耐冷性研究。结果表明,(1)不同回交世代与杂种与亲本间的苗期耐冷强弱差异较大,总体趋势为回交供体亲本>F5>BC1F4>BC2F3>BC3F2;揭示了随着回交世代的增加,其回交杂种苗期耐冷性减弱,越来越趋于轮回亲本,在耐冷育种上对回交供体亲本及其早世代材料进行选择更易获得苗期强耐冷材料。(2)同一稻作区,回交供体亲本的苗期耐冷强于杂种后代;稻作区划间,回交供体亲本及杂种F5总趋势相近,滇中一季籼稻粳稻区和滇东北高原粳稻区材料耐冷最强,而BC1F4、BC2F3和BC3F23个回交世代存在一定差异。     

Observations on the function of the glands of the foot of the pediveliger of Ostrea edulis during settlement

The use during settlement of secretions of the 9 different types of gland in the foot of the pediveliger of Ostrea edulis L. was examined experimentally. During settlement, there is a progressive decrease in the crawling speed of the larva and a strengthening of its bond with the substratum. Both changes are related to (a) a change from ciliary to muscular pedal locomotion; (b) the increasing acidity and viscosity of the mucoid secretions used; (c) the secretion of a byssus thread by the glands of the byssus duet; (d) changes in the form and composition of this byssus. At the termination of settlement, the entire contents of 2 types of gland are discharged. Their secretions give rise to the cement which permanently fixes the larva to the substratum. The 9 types of gland are utilised sequentially in a manner closely related to the 6 phases recognised in settlement behaviour.     

On the behaviour of the residence time at the bottom of the mixed layer

To understand why the findings of Deleersnijder et al. [(2006), Environ Fluid Mech 6: 25–42]—the residence time in the mixed layer in not necessarily zero at the pycnocline—are consistent with those of Delhez and Deleersnijder [(2006), Ocean Dyn 56:139–150]—the residence time in a control domain vanishes at the open boundaries of this control domain—, it is necessary to consider a control domain that includes part of the pycnocline, in which the eddy diffusivity is assumed to be zero. Then, depending on the behaviour of the eddy diffusivity near the bottom of the mixed layer, the residence time may be seen to exhibit a discontinuity at the interface between the mixed layer and the pycnocline. If such a discontinuity exists, the residence time is non-zero in the former and zero in the latter. This is illustrated by analytical solutions obtained under the assumption that the eddy diffusivity is constant in the mixed layer.     

豪猪消化系统的解剖研究

为了了解豪猪的消化生理,为豪猪的人工饲养技术研究提供基础依据,以达到高效饲养豪猪的目的,笔者对豪猪的消化器官进行了系统解剖研究.结果表明:豪猪的胃为单室胃.盲肠很发达,这与其能够消化植物纤维有关.豪猪肝脏很发达,其重量为402 g,是其体重的4.59%,肝脏分叶多而明显.     

刍议医院资产管理的现状及其对策

医院的固定资产和流动资产是医院赖以生存和发展的基础,是一项非经营性国有资产．目前公立医院固定资产、流动资产管理现状不容乐观,针对这种状况,首先分析问题形成的原因,然后提出管理的措施或建议,从而使资产管理工作规范化、制度化、科学化,使有限的卫生资源发挥出最大的社会效益和经济效益．参3．     

Mining of the forest and the time path of the price of timber

The paper analyzes the effect of transportation (site specific) costs and the effect of mining (depletion) of the forest on the time path of the price and of the net price of timber in two forestry models. The models differ in that one has zero costs and the other has positive costs. The analyses yield the standard mining theory results for certain cases. They also yield extentions of these results for cases with growth of the harvested trees and/or regeneration on the harvested land. The paper concludes, as one would expect, that the theory of the mine is useful in analyzing the time path of the price of timber.     

Adjusting the economy to the new energy realities of the second half of the age of oil

Our research indicates that, due to the depletion of conventional, and hence cheap, crude oil supplies (i.e. peak oil), increasing the supply of oil in the future would require exploiting lower quality resources (i.e. expensive), and thus will most likely occur only at high prices. This situation creates a system of feedbacks where economic growth, which requires more oil, would require high oil prices that will undermine that economic growth. We conclude that the economic growth of the past 40 years is unlikely to continue unless there is some remarkable change in how we manage our economy.     

Splitting the tail of the displacement kernel shows the unimportance of kurtosis

Animals disperse in space through different movement behaviors, resulting in different displacement distances. This is often described with a displacement kernel where the long-distance dispersers are within the tail of the kernel. A displacement with a large proportion of long-distance dispersers may have impact on different aspects of spatial ecology such as invasion speed, population persistence, and distribution. It is, however, unclear whether the kurtosis of the kernel plays a major role since a fatter tail also influences the variance of the kernel. We modeled displacement in landscapes with different amounts and configurations of habitats and handled kurtosis and variance separately to study how these affected population distribution and transition time. We conclude that kurtosis is not important for any of these aspects of spatial ecology. The variance of the kernel, on the other hand, was of great importance to both population distribution and transition time. We argue that separating variance and kurtosis can cast new light on the way in which long-distance dispersers are important in ecological processes. Consequences for empirical studies are discussed.     

Stimulation of fat-body production in the polyps of the coralPocillopora damicornis by the presence of mutualistic crabs of the genusTrapezia

A mutualism exists between the xanthid crabs of the genusTrapezia and their host corals,Pocillopora damicornis. It has previously been established that these obligate coral residents benefit the coral hosts by defending them against echinoderm predators and by increasing the survival of polyps located deep between the coral branches. In turn, the corals apparently benefit the crabs by producing lipid-filled structures on which the trapezid crabs feed; these fat bodies may contain some of the lipid which in previous studies of coral metabolism has been termed excess. It was determined by experiments conducted at the Hawaii Institute of Marine Biology that the presence of crabs in colonies ofP. damicornis stimulates the polyps to produce the lipid-filled fat bodies; removal of crabs causes corals to cease producing fat bodies. A structure very similar to the fat bodies ofP. damicornis has been reported inAcropora durvillei. Both of these coral genera ordinarily possess xanthid-crab mutualists. This association between branching corals and crustaceans may have evolved because corals of these genera provide shelter among their branches and because these shallow-water corals are evidently capable of releasing lipid which is excess to the corals' metabolic needs, but which can be utilized by the crabs.     

三峡库区消落带土壤中铅污染调查

报道了三峡库区长江干流及小江支流消落带土壤中重金属铅含量背景值的调查结果。结果表明，目前土壤未被重金属铅污染。