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1.
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。 相似文献
2.
《草业学报》2020,(6)
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。 相似文献
3.
对3种赖草属植物和3种偃麦草属植物花粉母细胞的减数分裂过程中花粉粒形态、饱满度和生活力进行了观察与比较研究，结果表明：赖草、大赖草、中间偃麦草、巴顿硬叶偃麦草、茹莎娜硬叶偃麦草的PMC减数分裂过程中存在分裂期不同步现象；巴顿硬叶偃麦草和茹莎娜硬叶偃麦草在后期Ⅰ同源染色体分离时产生染色体桥的异常现象，巴顿硬叶偃麦草在中期Ⅰ出现染色体落后现象；PMC减数分裂的胞质分裂方式为连续型；赖草属中，大赖草的3－细胞花偻百分率高于2－细胞花粉；偃麦草属中，巴顿硬叶偃麦草的3－细胞花粉百分离高于2－细胞花粉，而中间偃麦草的3－细胞花偻百分率低于2－细胞花粉，其花偻生活力高于其它种。 相似文献
4.
6种根茎型禾草PMC减数分裂及花粉形态的研究 总被引：1，自引：0，他引：1
对3种赖草属植物和3种偃麦草属植物花粉母细胞的减数分裂过程中花粉粒形态、饱满度和生活力进行了观察与比较研究,结果表明赖草、大赖草、中间偃麦草、巴顿硬叶偃麦草、茹莎娜硬叶偃麦草的PMC减数分裂过程中存在分裂期不同步现象;巴顿硬叶偃麦草和茹莎娜硬叶偃麦草在后期Ⅰ同源染色体分离时产生染色体桥的异常现象,巴顿硬叶偃麦草在中期Ⅰ出现染色体落后现象;PMC减数分裂的胞质分裂方式为连续型;赖草属中,大赖草的3-细胞花粉百分率高于2-细胞花粉;偃麦草属中,巴顿硬叶偃麦草的3-细胞花粉百分率高于2-细胞花粉,而中间偃麦草的3-细胞花粉百分率低于2-细胞花粉,其花粉生活力高于其它种. 相似文献
5.
黄华属植物叶表皮特征及其生物学意义 总被引：11，自引：0，他引：11
在光学显微镜下观察披针叶黄华复合体、高山黄华复合体及黄华属其它种的叶表皮特征。结果表明,表皮细胞形状、垂周壁式样及气孔器类型具有重要的分类学意义。表皮细胞形状为多边型和不规则型,垂周壁式样为平直或具波纹。黄华属植物除新疆黄华,之字枝黄华,东亚黄华,柔毛黄华上表皮无气孔外,其余的上下表皮均具气孔,气孔器类型多为不规则型,只有紫花黄华为不等细胞型,有些无规则型中稍混有不等细胞型。笔者认为气孔器类型对划分属内种上等级具有一定价值。对披针叶黄华复合体、高山黄华复合体和黄华属不同种间气孔指数方差分析结果表明,气孔指数在居群水平及不同种间变化差异极显著,气孔大小及气孔指数主要受环境因子的控制。 相似文献
6.
7.
《中国草地学报》2019,(4)
利用光学显微镜对12种胡枝子属常见植物的叶表皮微形态特征进行研究,结果表明:12种胡枝子属植物叶表皮细胞形状有3种,分别为不规则形、长方形、不规则形和长方形均有;垂周壁式样有浅波状、深波状、平直—弓形、浅波状和平直—弓形均有4种;依据表皮细胞形状和垂周壁式样,12种胡枝子可以分为5类。气孔器普遍存在于所有类群的下表皮及大部分类群的上表皮上,有无规则型、不等型、平列型3种,以平列型为主;12种胡枝子属植物的气孔器长宽比在1.26～2.11之间,截叶铁扫帚和铁马鞭气孔长轴的差异最显著;气孔器密度在23.7～1135.5个/mm~2之间;气孔指数为1.5%～25.7%,各种间差异显著。表皮毛普遍存在于下表皮及大部分类群的上表皮上,长短和密度因种而异。这些叶表皮微形态特征是胡枝子属植物对不同生态环境的形态响应,可作为部分胡枝子属植物种间分类的依据。 相似文献
8.
对诺丹冰草种子发育过程的切片进行观察和研究。合子的第一次分裂为横分裂。形成顶细胞和基细胞。接着顶细胞纵分裂。基细胞横分裂，胚胎发生属紫宛型。胚发育经过椭圆形至棒形。并出现凹陷。开始初分化直至成熟胚。部分种子出现有斜向原胚及胚囊中缺少胚的现象。胚乳为核型胚乳．胚乳细胞化始于多细胞原胚期。成熟胚乳最外层发育糊粉层。其它胚乳细胞充满淀粉粒。珠心与珠被在胚发育过程中细胞质作为营养物质被吸收、解体。细胞壁则被挤压成为一厚壁层，构成乳熟期的种皮。子房壁细胞中的大量淀粉粒在胚、胚乳的发育过程中作为营养物质被吸收。 相似文献
9.
应用光学显微镜对西北农林科技大学植物标本馆中分布于陕西省的14种小檗属(Berberis)植物的叶表皮微形态特征进行了研究。结果表明:14种小檗属植物叶表皮细胞形状有多边形和无规则形两种;垂周壁式样有平直-弓形、浅波形和深波形3种。叶表皮外均有不同程度加厚的角质层。气孔器只分布在所有研究的14种小檗属植物的下表皮,形状为椭圆形、长椭圆形、宽椭圆形;气孔器类型大多为无规则型。这些特征与它们具有的耐旱性有一定的相关性。对气孔指数、气孔密度、气孔长宽比的数据分析表明:陕西14种小檗属植物的气孔指数差异较大,可作为种间分类的依据;气孔密度在特定几种植物间的差异较明显,可作为部分种的分类依据。 相似文献
10.
运用光学显微镜和扫描电镜的方法,对3种香根草属植物的叶表皮微形态特征进行观察和比较。结果表明,香根草属3个种的叶表皮皆由长细胞、短细胞、气孔器、微毛、刺毛、大毛和乳突所组成。长细胞为长方形,垂周壁呈深波状或浅波状,短细胞有哑铃形、十字形,结节形;气孔器均为纵列型,副卫细胞为圆屋顶形至三角形;上下表皮都具微毛和乳突,下表皮还具刺毛和大毛;叶片表面有一层厚厚的角质膜,并常有条状隆起。该研究说明香根草属植物叶表皮微形态既有种间相似的特征,又存在一定的特异性,可为本属种间的分类及其抗逆机理提供依据。 相似文献
11.
Imogen Rüsse Fred Sinowatz Laszlo Richter Margot Lehmann Edgar Schallenberger 《Anatomia, histologia, embryologia》1992,21(4):324-347
Yolk sac development was investigated in 69 ovine and 10 bovine embryos from the blastocyst stage to the 7th week of gestation. Light and electron microscopical findings are reported. The yolk sac in sheep and cattle is composed of an enlarged sac-like portion lying below the embryo and two ends which follow the elongated course of the trophoblast. In sheep, an open connection exists between the intestines and the yolk sac up to a crown-rump length (CRL) of 9 mm. It is closed by 12 mm CRL. The wall of the yolk sac is especially well vascularized in the enlarged, sac-like portion. Primary erythropoiesis occurs within the blood capillaries. In the blastocyst, the yolk sac entoderm is made up of elongated, flat cells. It becomes cuboidal in the 3 mm embryo (ovine) and later columnar. The up to 20 microns tall cells stain darkly and contain numerous light-colored vesicles. At 4.5 mm CRL light cells appear between the dark ones. Both cells are rich in rough endoplasmic reticulum (rER). The increased staining of the darker cells is due to an osmophilic cytoplasm and numerous, often parallel lamella of rER. The rER of the light cells is enlarged to irregularly-shaped cisternae, which nearly fill the entire cytoplasm and give them a rounded appearance. The dark cells contain polygonal nuclei, whereas those in the light cells are round with one or two nucleoli. The oval mitochondria have only a few peripheral cristae. Golgi fields are not very common. Cells of the entoderm are connected to one another over zonulae occludentes. They possess microvilli on the luminal surface and are supported by a basement membrane. From 5 mm CRL onwards (ovine), the yolk sac entoderm folds itself between the capillaries, thereby becoming stratified. The intercellular space between the cells expands as projections between neighboring cells interlock. Canaliculi arise between adjacent epithelia. The wall of the yolk sac thickens as a result of this infolding and the densely packed capillaries. Infoldings are especially predominant in the sac-like portion of the yolk sac, and only suggested in the ends. Involution of the yolk sac begins in the peripheral end segments and proceeds centripetally. Numerous glycogen particles appear in the yolk sac entoderm cells of the ovine fetus at a CRL of 36 mm, and by a CRL of 42 mm, the sac-like portion has also begun to show signs of degeneration. Mesenchyme is very sparse within the wall of the yolk sac throughout the entire period of development.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
12.
A seven‐month‐old purebred Nelore calf was diagnosed with a bilateral finger‐shaped swelling although more prominent at the left side of the scrotum, located longitudinal and parallel to epididymis corpus. The finding was present from 7 months of age up to castration (performed at 25 months of age). Scrotal circumference, testicular and epididymis consistency and symmetry as well as seminal quality were normal during the follow‐up period. The ultrasonographic appearance of the scrotal wall, pampiniform plexus, gonad and epididymis was normal. However, an anechoic region surrounded by a wall forming a sac‐like structure with a blind end at its dorsal pole was seen on the swelling area. The examination of fluid aspirated from the saccular contents revealed the presence of mononuclear cells mainly from lymphocytic and histiocytic type as well as some loosing degenerated mesothelial cells. Gross examination at castration revealed a blind sac‐like appendix derived from an evagination in the parietal layer of the tunica vaginalis. The structure of approximately 5.0 cm in length extended from the dorsal edge of the epididymis cauda. No adherences with surrounded tissues were observed. Histopathology of the sac wall showed a smooth inner surface composed by scarce mesothelial cells forming in some areas papillary‐like projections protruding to the vaginal cavity. Underneath, a thick layer of fibrous tissue mixed with collagen fibres and mononuclear inflammatory cells were seen. The potential consequences of this saccular formation at an older age in a bull are unknown. 相似文献
13.
用5MHz线阵探头对14只母犬从配种后18d开始，每2d用B超探查1次；配种后36～48d，每3d探查1次；48d以后，于52、57d各探查1次。结果表明，于配种后18～22d确诊7只犬妊娠，7只空怀。有3只犬分剐在配种后24、36、39d发生流产。观察胎囊、胎儿、胎心、胎动、胎儿脏器、胎儿骨骼出现时间和测量胎囊大小、冠臀长、胎儿身长、头长、双顶径、胸深和心区大小，证明胎囊大小、胎儿冠臀长、身长、头长、双顶径、胸深与胎龄呈显著正相关。在配种后18～30d，观察子宫暗区大小可预测胎龄。在配种32d以后，观测胸深、双顶径或头长。可精确预测胎龄。 相似文献
14.
采用石蜡切片技术，观察研究番木瓜长圆开型两性花的花器官发生和分化过程及其与外部形态关系。结果发现，番木瓜两性花的发育方式属于向心式，花部各器官由外向内依次分化发生。发育进程可以分为以下几个阶段:花芽未分化期，花芽分化期，花萼原基分化期，花冠原基分化期，雄蕊原基分化期，雌蕊原基分化期。花芽分化启动的时间非常短，在外部形态直径小于0.4mm左右时，花芽已开始分化。雄蕊的发育早于雌蕊，花粉粒成熟时，大孢子才处于球形胚或心形胚阶段。研究结果为生产上对两性花的花期和花性调控的时间选择提供了理论参考。 相似文献
15.
O J Ginther 《Equine veterinary journal》1989,21(3):171-174
Recent findings on the development and natural outcome of twins from Day 17 (immediately after fixation) to Day 40 are reviewed. Incidence of embryo reduction was increased significantly when the vesicles became fixed unilaterally, rather than bilaterally, and when the vesicles were unequal in diameter. Of 68 mares with twins on the day of fixation, post fixation embryo reduction occurred in 41 (60 per cent). The incidence of reduction was 41 of 48 (85 per cent) following unilateral fixation; reduction occurred in all of 22 mares with vesicles of dissimilar size (4 mm or more difference in diameter) and in 19 (73 per cent) of 26 mares with vesicles of similar size (0 to 3 mm difference). Embryo reductions were complete (vesicle no longer visible ultrasonically) by Day 20 (59 per cent of the reductions), during Days 21 and 30 (27 per cent), or Days 31 to 38 (14 per cent). In 80 per cent of the early reductions (by Day 20) the eliminated vesicle disappeared within one day. Reductions that occurred after Day 20 were preceded by a gradual decrease in size. As the number of days after Day 17 increased, the frequency of reduction decreased and the time required for completion of reduction increased. When the twins were dissimilar in diameter (4 mm or more), they were more likely to undergo reduction by Day 20. In summary, dissimilarity in diameter increased the likelihood of unilateral fixation, increased the incidence of reduction for unilaterally fixed vesicles, hastened the day of occurrence of reduction and shortened the interval from initiation to completion of reduction. The deprivation hypothesis proposes that embryo reduction occurs when a major portion of the three walled area of the yolk sac or the vascularised wall of the yolk sac or allantoic sac is in apposition with the wall of the adjacent vesicle rather than with the endometrium; the vesicle is deprived of adequate embryonal-maternal exchange and therefore regresses. 相似文献
16.
Chicken embryo propagation of type I avian adenoviruses 总被引：2，自引：0，他引：2
B S Cowen 《Avian diseases》1988,32(2):347-352
Forty-two clone-purified, cell-culture-propagated type I avian adenoviruses (AAV) representing 11 serotypes and two intermediate strains were evaluated for virus replication (evidenced by embryo death and lesions) resulting from the inoculation of specific-pathogen-free chicken embryos via the chorioallantoic sac or yolk sac. Commonly observed embryonic changes were death, stunting and curling, hepatitis, splenomegaly, congestion and hemorrhage of body parts, and urate formation in the kidneys. Basophilic or eosinophilic intranuclear inclusion bodies characteristic of fowl adenoviruses were observed in hepatocytes. The magnitude and relative uniformity of intra- and interserotypic embryo mortality, gross lesions, and virus titers was greater in embryos inoculated via the yolk sac. This work identifies the yolk sac as a practical and sensitive chicken embryo inoculation route for poultry diagnosticians to employ. It is suggested that the yolk sac may be a reliable alternative to cell culture for the successful isolation of all type I avian adenoviruses. 相似文献
17.
The postnatal development of the stomach in the Japanese field vole, Microtus montebelli , were studied with the light and scanning electron microscopes.
Three kinds of cells constituting the fundic glands, that is, mucous neck cells, parietal cells and chief cells were distinguished clearly by light microscopy to have been differentiated around 14 days old. At 4 days old, the structure of pyloric glands was similar to that of adult stage. The investigation on the development of esophageal sac, fundic stomach and pyloric stomach was made by measuring each area of the vertical section. The fundic stomach grew more rapidly than the esophageal sac and pyloric stomach. The ratio of esophageal sac to fundic stomach and pyloric stomach in the area was about 1.5: 2: 1 at 20 days old.
In the fundic glands, 5-hydroxytriptamine (5-HT)- and somatostatin-immunoreactive cells appeared first at 6 days old and at birth, respectively and in the pyloric glands, gastrin-, 5-HT- and somatostatin-immunoreactive cells appeared at 19th day fetus. Gastrin-immunoreactive cells showed a rapid increase in the pyloric glands after birth. The distribution and frequency of endocrine cells were similar to that of adult at about 20 days old.
The fimbria showed bank-like appearance at the beginning and thereafter they showed the process-like structure. The fimbria in both the appearance and the length at 60 days old was similar to that of adult stage.
As a whole, the stomach of the field vole seemed to became mature at 20 days old in the aspects of gastric endocrine cells and morphology of gastric wall, although the fimbria formation was not accomplished at the same period. 相似文献
Three kinds of cells constituting the fundic glands, that is, mucous neck cells, parietal cells and chief cells were distinguished clearly by light microscopy to have been differentiated around 14 days old. At 4 days old, the structure of pyloric glands was similar to that of adult stage. The investigation on the development of esophageal sac, fundic stomach and pyloric stomach was made by measuring each area of the vertical section. The fundic stomach grew more rapidly than the esophageal sac and pyloric stomach. The ratio of esophageal sac to fundic stomach and pyloric stomach in the area was about 1.5: 2: 1 at 20 days old.
In the fundic glands, 5-hydroxytriptamine (5-HT)- and somatostatin-immunoreactive cells appeared first at 6 days old and at birth, respectively and in the pyloric glands, gastrin-, 5-HT- and somatostatin-immunoreactive cells appeared at 19th day fetus. Gastrin-immunoreactive cells showed a rapid increase in the pyloric glands after birth. The distribution and frequency of endocrine cells were similar to that of adult at about 20 days old.
The fimbria showed bank-like appearance at the beginning and thereafter they showed the process-like structure. The fimbria in both the appearance and the length at 60 days old was similar to that of adult stage.
As a whole, the stomach of the field vole seemed to became mature at 20 days old in the aspects of gastric endocrine cells and morphology of gastric wall, although the fimbria formation was not accomplished at the same period. 相似文献
18.
J. Riggs J. F. Ladlow L. J. Owen J. L. Hall 《The Journal of small animal practice》2019,60(3):191-197
Internal obturator and/or semitendinosus muscle flaps were used to reinforce primary appositional rectal wall repair in three dogs and one cat in this case series. All three dogs incurred rectal wall compromise during surgical excision of anal sac tumours. The cat sustained bite wounds to the perianal region resulting in abscessation and a rectal tear. Our results indicate that application of an internal obturator and/or semitendinosus muscle flap can reduce the risk of rectal wall dehiscence after primary repair, and consequently the risk of pararectal abscess or rectocutaneous fistula formation. 相似文献
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应用流式细胞仪结合免疫荧光抗体技术对固始鸡和固始鸡胚胎免疫器官内T淋巴细胞亚群的动态变化和发育分化规律进行了研究.结果发现,(1)胚胎时期,胸腺内T淋巴细胞发育分化低,表现为成熟的T淋巴细胞(CD3~+)和不成熟的胸腺细胞均较少;出壳后,固始鸡胸腺内成熟T淋巴细胞增多,占胸腺细胞的30%左右,但大部分仍是未成熟的胸腺细胞.(2)脾脏内T淋巴细胞为成熟的T淋巴细胞(CD3~+),占淋巴细胞的60%左右.胚胎时期脾脏内CD3~+水平低,出壳后2周已达脾脏内正常水平(60%左右).(3)法氏囊内有少量的成熟T淋巴细胞(10%左右).结果表明,T淋巴细胞在固始鸡胸腺内增殖分化和成熟,脾脏和法氏囊内的成熟T淋巴细胞均来源于胸腺. 相似文献