田旋花营养器官及不定芽发生的解剖学研究

对田旋花营养器官的解剖学研究结果表明,叶为两面叶,栅栏组织和海绵组织发达。主脉为周韧型维管束,在其主脉的远轴面,紧领下表皮的为1－2层同化组织细胞。地上茎表皮内具由2层细胞组成的同化组织,维管组织呈连续的环状排列,木质部内外侧都为韧皮部。地下根状茎的结构类似地上茎的结构,维的维管组织发达,在次生生长中,中央初生木质部导管周围薄壁细胞分化产生大量薄壁细胞和韧皮部分子。根状芭茎上的不定芽及不定根由维管形成层活动产生,根上的不定芽也是由根的维管形成层产生。     

ISSR fingerprinting for the assessment of the bindweed biocontrol agent Stagonospora convolvuli LA39 after field release

AIMS: To develop a molecular identification method based on ISSR fingerprints to monitor the fungal leaf pathogen Stagonospora convolvuli LA39 used to biologically control bindweeds after a field release. METHODS AND RESULTS: The developed method proved to be suitable to clearly distinguish LA39 from resident Stagonospora spp. and was applied in two field experiments. First, the environmental persistence of LA39 was assessed in an overwintering experiment. LA39 could be re-isolated from infected bindweed 1 year after field application, but with very low frequency of occurrence. Secondly, LA39 was applied in an area with natural bindweed infestation and re-isolated from infected bindweed. The dispersal of LA39 during one season was poor (4-5 m). CONCLUSIONS: ISSR fingerprinting has been shown to be a valuable tool to monitor the environmental fate of S. convolvuli in the field. It is concluded that an LA39-based mycoherbicide will have minimal environmental impact caused by the restricted mobility, poor proliferation and poor persistence over seasons of LA39. SIGNIFICANCE AND IMPACT OF THE STUDY: Studies about the dispersal and survival of biocontrol agents after field release as well as the development of methods needed for this purpose are indispensable for a comprehensive risk assessment for biocontrol agents.     

西瓜不同发育时期的助细胞超微结构的变化

被子植物胚囊的“雌性生殖单位”,已在多种植物上进行了超微结构的观察,但大多都以卵细胞受精前后的结构变化为主要研究内容。对于“雌性生殖单位”中的另一重要成员——助细胞,在不同发育状态下其结构变化的详细资料不多,尤其是助细胞退化后的物质去向,少见报道。本研究主要观察了西瓜不同发育时期(受精前后)、不同发育状态(柱头授粉和未授粉)的助细胞超微结构,以期为研究助细胞在双受精中所起作用提供新的资     

莴苣助细胞发育过程中钙的分布研究

用焦锑酸盐沉淀法对莴苣助细胞中的钙分布进行了观察。结果表明,开花前3天刚形成的助细胞中的钙颗粒很少:开花前2天助细胞壁中的钙颗粒增加;开花前1天助细胞珠孔端细胞壁加厚,其中积累了许多钙颗粒:开花当天助细胞珠孔端的丝状器中聚集了大量的钙颗粒。授粉后1h时两个助细胞的结构和钙分布发生差异,一个呈退化状,其中的钙颗粒明显增多,另一宿存助细胞中的钙分布与授粉前相似。去雄不授粉1天后两个助细胞均保持完好,且两助细胞中的钙分布没有明显差异,表明由花粉管引起一个助细胞中钙含量增加进而导致了助细胞退化。退化助细胞在卵细胞与中央细胞之间形成一薄层。助细胞退化后不同部位的钙颗粒呈现出与受精作用密切有关的变化:授粉后1h时,钙主要聚集在近合点端部位;授粉后2.5h卵细胞即将受精,这时许多细小的钙颗粒主要聚集在卵细胞与中央细胞之间的薄层中;授粉后4h精、卵细胞已融合,这时退化助细胞合点端的钙颗粒明显减少,而在其珠孔端又聚集了较多的钙。上述助细胞中的钙含量变化与吸引花粉管进入胚囊和促使精卵细胞融合密切有关。     

多胚水稻ApⅢ（双13）的胚胎学观察

对多胚水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）ＡｐⅢ的大量成熟颖果、人工萌发的幼苗和开花后３～５ ｄ 的幼嫩颖果进行的整体解剖和显微制片观察表明：ＡｐⅢ的５０００粒成熟颖果中,８９．０％ 含单胚单苗,８．９％ 和１．２％分别含双胚双苗和三胚三苗;７００多粒幼嫩颖果中,９０．０％ ～９５．０％ 含单胚,５．０％ ～７．０％ 含双胚。因制片的数目有限,未见到含三胚的;在含单胚和多胚颖果中,胚均位于同一胚囊的珠孔端,未见到胚囊以外存在不定胚。根据上述结果,似可以认为ＡｐⅢ单粒颖果的双胚和三胚是由同一胚囊内的卵细胞和１或２个助细胞受精或不受精发育而来的     

Embryological Observation on the Apomictic Rice-ApⅢ (Shuang 13)

Since 1988s, the phenomenon of multiple seedlings and multiple embryoes of apomictic rice, Ap Ⅲ (Shuang 13) has been interestingly concerned. Embryological investigation of Ap Ⅲ has been carried out with the whole dissection and conventional sectioning technique. The main conclusions are as follows: 1.8. 9 % of 5000 matured caryopsises, contained one embryo in a caryopsis, from which single seedling arose, while 8.9 % twin embryoes and 1.2 % triplet embryoes of which developed two seedlings and triple seedlings respectively; 2. In over 700 young caryopsises, 90.0%～95.0% contained only one embryo, 5.0%～7.0% twin embryoes, except a few of the ovules with absorptive embryo sac or embryo and endosperm. Triplet embryoes caryopsis could not be traced further due to their low frequency; 3. Authors' materials showed that all the single, twin and triplet embryoes were situated at the micropylar end in one embryo sac of young ovule and no adventitious embryo was seen outside the embryo sac of ovules. From the aforementioned results, it can be infered that albeit single embryo is derived from the egg cell yet it could be possible twin or triplet embryocs may be developed from the egg cell and one or two of the synergids either or not through fertilization.     

多胚水稻品系SB—1的细胞胚胎学研究：助细胞无配子生殖

对多胚水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）品系ＳＢ－１ 自然群体中单倍体来源进行的细胞胚胎学研究表明,卵器中的一个或两个助细胞能在受精之前发育成胚,其发生率分别为观察子房数的２．２４％ 和１．７５％ 。在１ 个助细胞提前发育成胚的胚囊中观察到双受精作用。在开花后３—８ ｄ的颖果中观察到１．６２％ 的与合子胚迥异的异位瘦长单胚和０．８１％ 的有胚无胚乳子房,根据胚所处的位置认为其来源于助细胞无配子生殖。此外,还观察到极少数的中央细胞未经受精自发产生胚乳的现象。讨论了ＳＢ－１中发生的无配子生殖的意义     

Development and function of the synergid cell

The synergid cells are located in the female gametophyte and are essential for angiosperm reproduction. During the fertilization process, a pollen tube grows into one of the synergid cells, ceases growth, ruptures, and releases its two sperm cells into this cell. The synergid cells produce an attractant that guides the pollen tube to the female gametophyte and likely contain factors that control arrest of pollen tube growth, pollen tube discharge, and gamete fusion. The synergid cells contain an elaborated cell wall at their micropylar poles, the filiform apparatus that likely plays a role in pollen tube guidance and pollen tube reception. Recent genetic, molecular, and physiological studies in Arabidopsis, maize, and Torenia have provided insights into synergid cell development and the control of pollen tube growth by the synergid cell.     

霜霉一新种——薄荷霜霉

本文报道寄生在薄荷(Mentha aruensis L.)叶片上的一种新的霜霉,命名薄荷霜霉(Peronospora menthae X.Y.Cheng et H.C.Bai)对新种进行了汉文和拉丁文描述。     

裂叶苣荬菜的研究

本文对裂叶苣荬菜(Sonchus arvensis L)进行了初步研究。考察了它的植物生态特征和分布环境,预试了化学成分并进行了临床病例观察。为裂叶苣荬菜以其本名作为治疗肝炎的草药入药提供了可靠的依据。     

Gametophytic pollen tube guidance

The concept of a pollen tube attractant was proposed in the late nineteenth century when pollen tubes were found to grow toward excised pistil tissues on medium. Since then, for about 140 years, plant biologists have tried to identify the pollen tube attractants. However, no molecule has been convincingly demonstrated to be the true attractant that actually controls the navigation of pollen tubes in the pistil. The past decade has seen substantial progress in this field in terms of our understanding of the various mechanisms of pollen tube guidance. It was suggested that diffusible pollen tube attractants might provide localized signals that affect the directional growth of the pollen tube, especially in the last phase of guidance by the target female gametophyte. Here, we review the mechanisms of pollen tube guidance, with special focus on the gametophytic guidance and the attractant. The necessary and appropriate conditions required by the true attractant will be discussed. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Specific Neurochemical Derangements of Brain Projecting Neurons in Apolipoprotein E-Deficient Mice

Abstract: Apolipoprotein E (apoE)-deficient mice provide a useful system for studying the role of apoE in neuronal maintenance and repair. Previous studies revealed specific memory impairments in these mice that are associated with presynaptic derangements in projecting forebrain cholinergic neurons. In the present study we examined whether dopaminergic, noradrenergic, and serotonergic projecting pathways of apoE-deficient mice are also affected and investigated the mechanisms that render them susceptible. The densities of nerve terminals of forebrain cholinergic projections were monitored histochemically by measurements of acetylcholinesterase activity, whereas those of the dopaminergic nigrostriatal pathway, the noradrenergic locus coeruleus cortical projection, and the raphe-cortical serotonergic tract were measured autoradiographically using radioligands that bind specifically to the respective presynaptic transporters of these neuronal tracts. The results obtained revealed that synaptic densities of cholinergic, noradrenergic, and serotonergic projections in specific brain regions of apoE-deficient mice are markedly lower than those of controls. Furthermore, the extent of presynaptic derangement within each of these tracts was found to be more pronounced the further away the nerve terminal is from its cell body. In contrast, the nerve terminal density of the dopaminergic neurons that project from the substantia nigra to the striatum was unaffected and was similar to that of the controls. The rank order of these presynaptic derangements at comparable distances from the respective cell bodies was found to be septohippocampal cholinergic > nucleus basalis cholinergic > locus coeruleus adrenergic > raphe serotonergic ? nigrostriatal dopaminergic, which interestingly is similar to that observed in Alzheimer's disease. These results suggest that two complementary factors determine the susceptibility of brain projecting neurons to apoE deficiency: pathway-specific differences and the distance of the nerve terminals from their cell body.     

中国苋科一新分布

发表了作者在皖北植物资源调查中采集到的1500余号标本,经研究鉴定发现,中国苋科一新分布,阿尔维长序苋(D. arvensis Forsk.)文中所及标本,存安徽大学资源植物标本室。     

中国苋科一新分布

发表了作者在皖北植物资源调查中采集到的1500余号标本,经研究鉴定发现,中国苋科一新分布,阿尔维长序苋(D. arvensis Forsk.)文中所及标本,存安徽大学资源植物标本室。     

随机扩增多态DNA(RAPD)在野蘑菇杂交育种中的应用

野蘑菇 (AgaricusarvensisSchaeffex .Fr.)是蘑菇属 (Agaricus)又一种近年来广泛栽培的食用菌。由于它的菌丝细胞具有多核 ,无锁状联合 ,以及人们对它的繁殖模式和生活史认识的不足 ,给杂交育种工作造成了较多困难。运用随机扩增多态DNA遗传标记技术 ,结合拮抗试验和核相分析 ,对自育的单孢菌株之间的杂交试验进行分析研究。结果表明 :两个相互亲合的同核体菌株被配对培养时 ,交配反应出现 ,并形成异核体的后代。可能野蘑菇具有双重的交配繁殖系统———     

烟草雌性细胞原生质体的融合实验

将聚乙二醇诱导的单对原生质体融合技术应用于烟草（Ｎｉｃｏｔｉａｎａ ｔａｂａｃｕｍ ）雌性细胞体外融合,成功地进行了雌性细胞间,雌、雄性细胞间,雌性细胞与体细胞间各种组合的融合实验。此外,应用微滴培养与微室饲养培养两种方法诱导了体细胞原生质体分裂并形成细胞团,为数目有限的性细胞融合体的培养奠定了技术基础     

水稻雌蕊与胚囊中钙的超微细胞化学定位

用焦锑酸盐沉淀法对水稻（OryzasativaL．）授粉前后雌蕊和胚囊中的钙进行了超微细胞化学定位。结果表明,柱头乳突细胞表面和花柱薄壁细胞中均含钙沉淀;开花前1d,整个胚囊中含钙较少,两个助细胞中钙分布无差异;临近开花时,1个助细胞已退化,其钙含量明显增加;开花后6h,胚囊已受精,退化助细胞中钙含量进一步增加;受精前卵细胞中钙主要分布在液泡中,核和胞质中较少;受精后,其钙含量明显增加,主要分布于核中。重点讨论了钙与助细胞退化和卵细胞激活的关系。     

天竺葵雌性生殖单位的超微结构

应用透射电镜研究了临近受精时天竺葵(Pelargonium hortorum Bailey)胚囊中的卵细胞、助细胞和中央细胞的结构。证明了卵细胞与助细胞以及助细胞与助细胞之间从合点端至珠孔端有很大的面积以质膜分界,仅珠孔端少部分以壁分隔。卵细胞与中央细胞之间同样缺乏细胞壁。在卵细胞的合点端,两质膜不同程度地分离形成宽窄相间的间隙。在间隙的絮状基质中存在小泡,这些小泡的产生似与卵和中央细胞中周质内质网的活动有关。推测小泡为多糖性质,可能为合子新壁的建造提供物质。卵细胞质中含巨大线粒体,质体和内质网也较丰富。基于超微结构的特征,可认为卵细胞具高度的生理合成活动的潜能。中央细胞极核位于珠孔端与卵器细胞毗邻,有利于在双受精作用中同时发生精细胞与卵细胞和精细胞与中央细胞核的融合。中央细胞的侧壁在珠孔端形成内突,具传递细胞的特点,表明这是雌配子体向孢子体摄取营养的重要部位。助细胞的细胞质含丰富的细胞器,这与多数植物中的相似,但具几个明显的特征,即核中存在微核仁,内质网形成圆球体或脂体,线粒体富集在丝状器的附近。传粉后花粉管进入胚囊之前,两个助细胞中一个退化。     

田茜（茜草科）——中国大陆新归化植物

报道了中国大陆新归化植物——田茜（Sherardia arvensis L.）,并对其形态学特征进行了详细描述,同时对其入侵风险做了简要评估。     

刺旋花种群形态参数的通径分析与亚灌木个体生物量建模

对刺旋花４种形态参数的通径分析表明,冠幅（Ｃ）对种群生物量作用最大,其它依次为分枝数（ＢＮ）、基径（ＢＤ）和高度（Ｈ）．在此基础上,选取ＣＨ和常用变量Ｄ２Ｈ,就７种常规方程对生物量建模的效果进行比较,并同时建立营养器官和单株总生物量的预测方程．结果表明,选取变量ＣＨ较Ｄ２Ｈ合适,线性回归方程较其它方程准确直观,其中单株生物量择优预测方程为Ｙ＝１２．１０＋０．０１０５ＣＨ（Ｒ＝０．９８３,Ｐ＜０．０１）．