花粉的结构与发育

１花粉的产生植物雄蕊是被子植物产花粉的器官 ,由纤细的花丝和产生花粉的花药组成 ,花药是由弯曲的花粉囊所组成。每个花粉囊中充满着花粉粒 ,在花药发育的早期 ,花粉囊内产生花粉母细胞 ,每一个花粉母细胞经过减数分裂产生４个称为孢子的单倍体细胞 ,每个小孢子又分化成为一个花粉粒。当花粉粒成熟时花药沿一裂缝开裂 ,散出其中的花粉。２花粉的形状花粉粒是植物的雄配子体 ,其中孕育着雄性生殖细胞或精子以及营养细胞 ,花粉还有内壁和外壁。内壁主要成分为纤维素、果胶质、半纤维素及蛋白质 ,较薄 ,软而有弹性 ;外壁主要成分为孢粉素和纤…     

东北野豌豆族植物叶形态结构的研究及其分类学意义

本研究采用了扫描电镜、叶片透明及GMA切片法,深入研究了东北野豌豆族3属,22种,2变种及1变型叶的形态结构。结果表明,叶为偶数羽状复叶,小叶1至多对,多为卵形。叶表皮细胞垂周壁多为波形。山黧豆属与豌豆属的气孔主要为不等型,野豌豆属多为无规则型。多数物种的叶片具单细胞非腺毛和多细胞腺毛。叶柄横切面多为戟形,近轴面具沟槽。叶柄具多个维管束,排列成V形、心形或圆形。本研究为野豌豆族的分类提供了形态学依据,并为探讨这一类群的系统演化及深入研究豆科的系统学提供形态学基础。     

花粉的可消化性

花粉是被子植物有性生殖中的雄配子体,在雄蕊花药的花粉囊内产生,是一些很细小的粉状颗粒。成熟的花粉粒含有2—3个细胞,即1个营养细胞和1个生殖细胞,或1个营养细胞和2个精细胞。花粉粒的形态和结构花粉粒的形状、大小、外壁表面的纹型特征、萌发孔的数目或沟缝的分布,随植物的种类而不同。这些     

东北堇菜属植物叶形态结构的研究及其分类学价值的探讨

采用GMA半薄切片及叶表皮撕取法,深入研究了东北堇菜属28种及1变种叶的形态结构。结果显示堇菜属植物叶为心形、肾形、卵形及长三角形。托叶多为披针形。毛状体为单细胞非腺毛或两细胞非腺毛。气孔主要为不等型。叶柄横切面多呈半圆形,两侧通常具翼,维管束常为3个,呈马蹄形或肾形,少数物种叶柄内具通气组织和纤维。堇菜属不同物种叶柄的形态结构有差异,其特征在组内相似,可作为种及组划分的形态依据。本研究为须毛柱头亚属、美丽堇菜亚属及堇菜组的建立,裂叶堇菜组并入合生托叶组,早开堇菜、茜堇菜和紫花地丁作为3个独立的种提供了形态学依据,并为进一步深入研究中国堇菜属及堇菜科提供了基础资料。     

东北毛茛科植物营养器官结构及其系统学意义

首次采用了GMA半薄切片及叶表皮撕取法,深入研究了东北毛茛科17属、27种及4变种营养器官的形态结构。结果显示毛茛科植物根、茎、叶的角质层,气孔、叶柄横切面形状,通气组织等特征具有重要的系统学价值。唐松草属植物具极厚的角质层,而这种厚角质层不存在于所研究的其他物种;属内不同物种气孔的分布相同,而属间有区别;毛茛组不同物种根和茎的皮层均具通气组织;叶柄横切面形态在属内不同物种相近。此外研究还揭示出毛茛属、水毛茛属和碱毛茛属植物根及茎具相似的结构,如根具溶生性通气组织,导管呈束状分布及无次生木质部,支持前人将三者归入广义毛茛属。驴蹄草属与金莲花属根皮层结构及气孔分布等存在很大不同,二者应属于不同类群,为分子系统学的结果提供了形态学依据。     

新疆高葶韭雄蕊开花动态特征与花粉育性研究

为进一步研究国内仅分布于新疆的高葶韭（Allium obliquum）花粉发育、传粉生物学以及为高葶韭人工有性繁殖提供理论依据和试验方法,定株观察了花期高葶韭雄蕊的开花进程以及形态变化特征,并采用6种方法测定了高葶韭花粉育性。结果显示,高葶韭单花开放经过5个形态变化至花药脱落和花被片完全闭合。高葶韭内轮花丝先于外轮花丝伸长,内轮花药先伸出花被片,随后外轮花药陆续伸出花被片。雄蕊开放至6枚花药全部脱落4～5 d。单枚花药从散粉到完全散粉一般需要1.5～2.0 h。散粉后高葶韭花粉活力（萌发率） 0～10 h内超过50%。0.5%氯化三苯基四氮唑、四甲基偶氮唑、联苯胺和离体萌发法可以用来检验高葶韭花粉活力和花粉萌发率,而醋酸洋红和碘 碘化钾不适合高葶韭花粉育性的测定。高葶韭具有雌雄异熟、雄蕊先熟于雌蕊的花部特征,花粉可育且寿命短。     

东北委陵菜属植物叶形态结构的研究及其分类学价值的探讨

首次采用了GMA半薄切片法对委陵菜属23种植物叶的形态结构进行了比较形态学研究。结果表明,东北委陵菜属植物的托叶类型多样,分为披针形、卵状披针形、卵圆形和叶状;叶柄横切面多为心形,此外还有马蹄形、近三角形和近圆形,维管束常为3个;叶表皮具腺毛和非腺毛;气孔均为无规则型,主要分布在下表皮;多数物种具韧皮纤维。本属木本植物金露梅及银露梅叶的许多特征(如毛状体类型,维管束数量及结构)与草本物种相似,故支持前人将二者放在委陵菜属。本研究可为委陵菜属的分类提供形态学依据,并为进一步深入研究中国委陵菜属以及蔷薇科的分类及系统学提供重要的基础资料。     

19种菊科植物花药结构及绒毡层的发育类型研究

花药结构和绒毡层的发育类型对菊科植物的系统分类和系统演化具有重要的意义。本研究采用苏木精和苯胺番红整体染色以及石蜡切片的方法,通过显微镜观察,对菊科7族19属19种植物花药结构及绒毡层的发育类型进行研究。结果表明,18种植物的花药由4个花粉囊组成,1种由2个花粉囊组成。花粉囊壁由表皮、药室内壁、中层和绒毡层4层细胞组成,中层细胞在花粉母细胞时期解体。随着花粉粒的形成,药室内壁先“U”形增厚,再进行条带状增厚。花粉母细胞胞质分裂类型有连续型和同时型2种,小孢子四分体以四面体形为主。绒毡层的发育类型有变形绒毡层和分泌绒毡层两种类型,变形绒毡层是管状花亚科植物的共同特点,分泌绒毡层是舌状花亚科植物的共同特点。从向日葵族向菊苣族的逐渐演化过程中,绒毡层的发育类型从向日葵族的变形绒毡层、经过变形绒毡层向分泌绒毡层的过渡类型逐渐演化为菊苣族的分泌绒毡层。变形绒毡层的形态在管状花亚科不同族之间有明显差异,绒毡层的发育类型和形态可以作为亚科和族分类的依据之一。     

花椰菜2种雄性不育系花器特征及花药发育的细胞学研究

本试验以花椰菜细胞质雄性不育系09-R9、保持系09-24和温敏细胞核雄性不育系GS-19为试验材料,采用形态学和细胞学方法研究2种雄性不育系的形态特征和花药发育的细胞学特点。结果表明,2种雄性不育系在育性转换、花器形态特征及花药发育的细胞学特征都存在着差异。不同温度处理的09-R9、09-24和GS-19之间的育性转换存在差异。09-R9和09-24的育性不受温度影响,09-R9表现为不育,09-24完全可育;GS-19的育性受温度影响,高温(20 ℃)不育,低温(15 ℃)育性恢复。GS-19和09-R9花蕾和花药大小差异显著,GS-19花蕾和花药显著小于09-R9;不育株与其可育株花的差异达到显著水平,不育株花显著小于可育株。显微结构观察发现2种雄性不育系之间的花药败育时期和方式不同,09-R9花药早期可以形成外形正常的花粉囊,但囊内物质随着花蕾的发育逐渐解体,最终这种不正常的花粉囊全部解体消失,花药发育受阻于花粉母细胞形成之前,属于无花粉囊败育类型。GS-19的花药发育过程有花粉母细胞的分化,能形成正常花粉囊,不产生花粉粒或者产生微量的无生活力的花粉粒,花药发育受阻于花粉母细胞到四分体时期,属于花粉母细胞败育类型。超微结构观察发现,不育系09-R9和高温条件下不育系GS-19花药败育相似,发生在花粉母细胞减数分裂时期,没有四分体的形成,形成了花粉粒外壁发育异常的“拟小孢子”,最后“拟小孢子”逐渐降解,只剩下花粉空壳。说明2种雄性不育系的败育方式有差异,但是败育时期一致,花药发育均受阻于四分体形成之前。     

19种菊科植物花药结构及绒毡层的发育类型研究

花药结构和绒毡层的发育类型对菊科植物的系统分类和系统演化具有重要的意义。本研究采用苏木精和苯胺番红整体染色以及石蜡切片的方法,通过显微镜观察,对菊科7族19属19种植物花药结构及绒毡层的发育类型进行研究。结果表明,18种植物的花药由4个花粉囊组成,1种由2个花粉囊组成。花粉囊壁由表皮、药室内壁、中层和绒毡层4层细胞组成,中层细胞在花粉母细胞时期解体。随着花粉粒的形成,药室内壁先"U"形增厚,再进行条带状增厚。花粉母细胞胞质分裂类型有连续型和同时型2种,小孢子四分体以四面体形为主。绒毡层的发育类型有变形绒毡层和分泌绒毡层两种类型,变形绒毡层是管状花亚科植物的共同特点,分泌绒毡层是舌状花亚科植物的共同特点。从向日葵族向菊苣族的逐渐演化过程中,绒毡层的发育类型从向日葵族的变形绒毡层、经过变形绒毡层向分泌绒毡层的过渡类型逐渐演化为菊苣族的分泌绒毡层。变形绒毡层的形态在管状花亚科不同族之间有明显差异,绒毡层的发育类型和形态可以作为亚科和族分类的依据之一。     

中国十字花科果实微形态及其系统学意义

采用GMA半薄切片法,首次深入研究了中国十字花科(Brassicaceae)76种及7变种(包括9族35属)果实的微形态,结果显示十字花科果实分两侧压扁及背腹压扁。除乌头荠族、紫罗兰族的果实无毛状体外,其他7个族均具单细胞毛。毛状体分为4种类型:单毛不分枝、丁字毛、分叉毛及星状毛。独行菜族果实具翅,包括微翅、周翅、宽翅及披针形翅。中果皮通常由薄壁细胞层及纤维层构成,少数物种的中果皮细胞木化(如南芥族、独行菜族、香花芥族)。维管束多数,分布于果皮薄壁组织。假隔膜通常为2层薄壁细胞,但南芥族及香花芥族少数属种的假隔膜细胞木化,三肋菘蓝及厚壁荠未见明显假隔膜。十字花科果实特征通常在属内是稳定的,具有重要的分类学价值。本研究完善了十字花科果实形态学,为该科族或属的划分提供了形态学依据,为分子系统学的研究提供了形态学支持,并为进一步深入研究十字花科系统学提供了基础资料。     

中国蓼科植物花被片和果实形态结构及其系统学价值

首次采用了外部特征的观察,果皮细胞分离及GMA半薄切片法,深入研究了中国蓼科9属、64种、2变种的花被片及果实的形态结构。结果显示花被片边缘全缘,微波状或锯齿状。三出脉,网状脉或羽状脉。脉序的特征在属内是稳定的。果实多为三棱,双凸镜和近球形。外果皮几乎全为石细胞,石细胞多为镶嵌或栅栏状排列,具7种类型:1)近椭圆形,细胞壁波状;2)长柱状,细胞壁波状弯曲;3)近长方形,细胞壁具突起;4)长圆柱形,细胞壁具突起;5)近长方形,细胞壁平直;6)近椭圆形,细胞壁具突起;7)长条形,细胞壁波状。蓼亚科具类型1~5,酸模亚科具类型6和7。外果皮和中果皮细胞有单宁。本研究为中国蓼科的分类提供花被片及果实结构的依据,为分子系统学揭示的蓼科不是一个自然的类群提供了形态学支持,并为进一步深入研究蓼科的系统学奠定了形态学基础。     

抗裂荚箭筈豌豆荚果发育动态及其腹缝线结构

易裂荚箭筈豌豆(Vicia sativa)的荚果开裂主要是由离层和细胞失水产生的机械拉力导致的,但是在抗裂荚的箭筈豌豆中的组织结构尚不明确。该研究以抗裂荚的135号箭筈豌豆(V.sativasubsp.sativa No.135)为对象,对其荚果在发育过程中的形态特征、水分含量、发芽率及腹缝线横截面解剖结构等的动态变化进行观察分析,以探讨抗裂荚箭筈豌豆荚果的抗裂机理,以及为生产中确定其种子收获的适宜时间提供理论依据。结果显示,1)135号箭筈豌豆约在盛花后26d荚果变为棕黑色,荚果的大小、干重已经达到最大值,含水量较低,发芽率较高且硬实率较低。2)135号箭筈豌豆腹缝线处夹在两个维管束之间的薄壁细胞没有分化成离层,而是分化成与维管束细胞一样的厚壁细胞,将两个维管束连接起来,形成由厚壁细胞组成的整体。综上所述,盛花后26d荚果变为棕黑色时是135号箭筈豌豆的适宜收获时间,离层的丢失和分化形成的厚壁细胞是其荚果抗裂的主要原因。     

A VALENTINE‐SHAPED CARDIAC SILHOUETTE IN FELINE THORACIC RADIOGRAPHS IS PRIMARILY DUE TO LEFT ATRIAL ENLARGEMENT

Conflicting information has been published regarding the cause of a valentine‐shaped cardiac silhouette in dorsoventral or ventrodorsal thoracic radiographs in cats. The purpose of this retrospective, cross‐sectional study was to test the hypothesis that the valentine shape is primarily due to left atrial enlargement. Images for cats with a radiographic valentine‐shaped cardiac silhouette and full echocardiography examination were retrieved and independently reviewed. A subjective scoring system was used to record severity of radiographic valentine shape. Subjective radiographic evidence of left atrial enlargement in a radiographic lateral projection and a final diagnosis based on medical records were also recorded. A total of 81 cats met inclusion criteria. There was a strong positive correlation (P < 0.001) between echocardiographic left atrial size and severity of radiographic valentine shape. There was no effect of echocardiographic right atrial size on the severity of valentine shape, except when concurrent with severe left atrial enlargement. In this situation, right atrial enlargement increased the likelihood of observing a severe valentine shape. There was no effect of right atrial enlargement on the shape of the cardiac silhouette when left atrial enlargement was absent or only mild to moderate. There was no correlation between the category of final diagnosis of cardiac disease and the severity of valentine shape. Findings from this study supported the hypothesis that a valentine‐shaped cardiac silhouette in radiographs is due primarily to left atrial enlargement in cats, with right atrial enlargement only impacting the shape if concurrent with severe left atrial enlargement.     

Description of Pelonia africana n. g., n. sp. (Pentastomida: Sebekidae) from the lungs of Pelomedusa subrufa and Pelusios sinuatus (Chelonia) in South Africa

The terrapins Pelomedusa subrufa and Pelusios sinuatus taken from a water reservoir in the Northern Province, South Africa, were examined for pentastome infections. Two immature specimens, a patent female and a mature male, were obtained from the lungs of four hosts, each of which harboured a single specimen. Based on the morphology of the specimens the new monospecific genus, Pelonia africana n. g., n. sp., is described. It is characterized by smooth, dorsally convex hooks with sharply bent blades. The oral cadre is more or less U-shaped. Delicate chitinous fibres, which can be difficult to see, connect the lateral prongs anteriorly. In this, as well as the morphology of the copulatory spicules, it is most like Sebekia wedli. The latter, however, possesses spinous hooks, which are absent in P. africana. The hooks are slightly and the copulatory spicules markedly larger in P. africana than in S. wedli. The lack of a double-hooked collar at the terminal end of the cowry-shell shaped base of each copulatory spicule and the absence of a peg-like extension of the oral cadre into the oesophagus, distinguishes P. africana from members of the genus Alofia. The oral cadre of the South American species Diesingia megastoma, from aquatic chelonians, is more than twice the size than that of Pelonia and there is a distinct difference in shape. The hooks of the genus Diesingia are flat-topped, and both the anterior as well as the posterior fulcra carry cowl-like extensions. The number of annuli, 55-60 in D. megastoma and approximately 30 in P. africana, further separates the two genera. The most striking feature of Diesingia which sets it apart from Pelonia and the other genera of the family Sebekidae, is the configuration of its copulatory spicules. Pelonia and Diesingia share morphological features with all the other sebekiids, but it is the unique combination of diagnostic characters that separates the two genera from those, as well as from each other.     

贺兰山荒漠草原几种主要植物花粉形态观察

通过扫描电镜观察结果,描述了贺兰山荒漠草原植被6科、8属、10种主要植物的花粉形态特征。结果表明,在扫描电镜观察下,每种植物花粉的轮廓、形状、大小、表面纹饰、萌发器官类型及数量各不相同;同科或同属内种间总体形态特征相似,而细微特征存在明显差异。     

Morphological study of tracheal shape in donkeys with and without tracheal obstruction

Reason for performing study: There is limited information on the gross tracheal morphology of donkeys with or without tracheal abnormalities. Objectives: To: 1) examine the morphology of tracheas of donkeys with and without clinical and/or post mortem evidence of tracheal obstruction; 2) record the cross‐sectional dimensions and shapes of tracheal rings at fixed sites; and 3) document prevalence, sites and characteristics of detected tracheal abnormalities. Methods: The tracheas of 75, predominantly aged (median age 30 years, range 7–48 years) donkeys that died or were subjected to euthanasia on humane grounds were examined. Five had severe dyspnoea due to tracheal obstruction (with intercurrent lung disease in 3), while 7 had post mortem evidence of severe tracheal airway obstruction. Every 5th tracheal ring was dissected free and the inner and outer vertical and transverse dimensions and cross sectional areas were measured. Each dissected ring was photographed and the shape of the trachea was classified as normal or, in one of 6 abnormal grades, according to the type and degree of structural abnormality present. Results: The tracheas had a mean of 43 (range 34–50) tracheal rings that tended to be more oval in shape in the distal cervical region. Only 31.2% of rings examined had a circular to oval shape. Dorso‐ventral flattening was present in 0.9% of tracheal rings, dorsal ligament separation in 24.4%, slight cartilage deformity in 26.0%, moderate cartilage deformity in 10.4%, marked cartilage deformity in 1.9% and miscellaneous other abnormalities in 4.9% of tracheal rings. The 12 donkeys with ante or post mortem evidence of tracheal obstruction had significantly increased tracheal abnormality grade in comparison to the remaining donkeys. Conclusions and potential relevance: Structural tracheal abnormalities are present in most old donkeys, but generally do not cause clinical problems in these sedentary animals unless intercurrent pulmonary disease is present.     

Papillar morphology of the rumen of forest reindeer (Rangifer tarandus fennicus) and semidomesticated reindeer (R. t. tarandus)

The papillar morphology of the ventral and dorsal rumen of the wild forest reindeer (Rangifer tarandus fennicus Lönn.) and semidomesticated reindeer (R. t. tarandus L.) was studied in October and November 1996. The morphological measurements which were carried out were: the lengths of the papillae, the number of the papillae per square centimetre, the cross‐sectional area and perimeter of sections cut from the middle of papillae. From these measurements mean papillar volume, areal papillar volume, mean papillar (epithelial) surface area, areal papillar surface and surface enlargement factor were calculated. No differences in these measurements between ventral and dorsal walls of the rumen were evident. The semidomesticated reindeer had longer papillar perimeters, larger mean and areal papillar surface areas, larger mean papillar volumes, and a larger surface enlargement factor in the ventral rumen than did forest reindeer. This may be a result of differences between feeding habits, the semidomesticated reindeer preferring a diet including more plants rich in carbohydrates e.g. lichens, which has resulted in a high production of volatile fatty acids and thus stimulation of papillar growth.     

牛肝胆超声断层扫描的研究

利用Ｐｉｅ Ｄａｔａ ＳＣ－４００型超声扫描仪,对１２头临床健康牛进行肝胆超声断层扫描的反复实验。结果：牛肝脏可在右侧第８～１２肋间显示,呈均匀的弱回声影像,肝下缘切面轮廓为锐角的楔状图像,肝壁面及脏面整齐、清晰：门静脉和肝静脉能在多数牛的第１０～１２肋间显示,并可根据其管壁回声强弱等加以分辨;胆囊多在右侧第１１或１０肋间探到,为边缘光滑整齐、轮廓清晰的类三角形或椭圆形无回声液性暗区。并测定了试验