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1.
山西省种子植物多样性分布格局与环境关系的研究   总被引:4,自引:0,他引:4  
采用除趋势对应分析(DCA)、典范对应分析(CCA)对山西省12个区域的种子植物多样性及区系地理成分的分析表明,全省种子植物多样性格局可分为3类:第1类为山西省西部和北部山地,热量相对较低,海拔较高,降水随海拔升高而增加,气候垂直变化明显,小生境类型较多,分类强度大,区系成分中以北温带、旧世界温带属占绝对优势。第2类为山西中部地区,地势相对较低,水热条件中等,北温带成分仍为优势种,但旧世界温带分布属和泛热带分布属的比例增加。第3类为山西南部和东南部山区,降水量相对较高,但温度也高,蒸发量大,属的区系成分中以北温带成分为优势,但第二优势成分为泛热带亚洲成分,与前2类地区相比,热带成分明显增加。  相似文献   

2.
Leghaemoglobin from the root nodules of kidney bean (Phaseolus vulgaris) reacts in alkaline glycine solutions as a glycine oxidase in a reaction that may also be regarded as a coupled oxidation. Leghaemoglobin is reduced to the ferrous form by glycinate, the oxygen complex is formed, and finally the haem is attacked to yield a green reaction product. Glycine is simultaneously oxidized to glyoxylate, and hydrogen peroxide is generated. The initial velocity of the formation of the green product is proportional to the concentrations of leghaemoglobin and glycine, and the optimum pH for the reaction is 10.2. The green product is not formed if carbon monoxide, azide of imidazole is bound to the haem, whereas oxidation of glycine to glyoxylate is not inhibited by azide and not essentially by carbon monoxide. Haem breakdown is activated by digestion of leghaemoglobin by carboxypeptidase, and partly inhibited by catalase and superoxide dismutase.  相似文献   

3.
短柄五加大,小孢子发生和雌,雄配子体发育的研究   总被引:6,自引:2,他引:4  
王仲礼  田国伟 《植物研究》1998,18(2):177-183
短柄五加花药5枚,每个花药四个花粉囊。小孢子母细胞减数分裂时,胞质分裂为同时型,产生正四面体形的四分体。花药壁由表皮、药室内壁、中层和绒毡层四层细胞组成,其发育类型为双子叶型。腺质绒毡层,其细胞为二核。三细胞型花粉。子房5室,每室两个胚珠,上胚珠败育,下胚珠可育。下胚珠倒生,具单珠被,厚珠心。大孢子母细胞减数分裂形成线性排列的四个大孢子,雌配子体发育属蓼型。开花当天,花粉散开,雌配子体尚未成熟,处  相似文献   

4.
扬子鳄视觉器官组织学研究   总被引:11,自引:0,他引:11  
吴孝兵  王朝林 《动物学报》1993,39(3):244-250
本文用光镜和电镜研究了扬子鳄(Alligator sinensis)的组织学,同时测量了其眼球的一些光学参数.扬子鳄眼球呈扁圆球形,角膜径与球径的比值为1:1.44;晶状体与角膜的比值为1:1.40。角膜内具鲍氏膜;虹膜内的括约肌、睫状体内的睫状肌均属横纹肌,视细胞椭圆体内线粒体嵴突与线粒体长轴相平行,这与报道的其它鳄类不同。虹膜内未见扩瞳肌纤维,角膜缘缺巩膜小骨片,晶状体环垫薄,因而其视觉调节能力仍然很弱。视网膜中视细胞由视杆细胞、单锥细胞、双锥细胞组成,其中以视杆细胞占多数。视细胞与神经节细胞核比值平均为2.5:1,表明扬子鳄的组织结构与其弱光视觉相适应。  相似文献   

5.
羚牛(Budorcas taxicolor)部分脏器特点的观察   总被引:2,自引:2,他引:0  
本文对2只羚牛的雌性生殖器官及肝、肾、脾等脏器进行了形态描述,并与黄牛及羊的相应器官进行了比较,为探讨羚牛的分类地位提供了解剖学资料。  相似文献   

6.
四川自贡发现合川马门溪龙新材料   总被引:1,自引:0,他引:1  
叶勇  欧阳辉  傅乾明 《古脊椎动物学报》2001,39(4):266-271,T001
记述了产自四川自贡上侏罗统的一具较完整的蜥脚类恐龙骨架 ,将其归入合川马门溪龙 (Mamenchisaurushochuanensis)中。新材料的发现弥补了合川种正型标本的不足 ,对合川种的特征作了重要补充 ,同时也使我们对马门溪龙的末端尾椎形态有了新的认识。  相似文献   

7.
爪鲵消化系统的解剖学和组织学初步研究   总被引:5,自引:0,他引:5  
本文报道了爪鲵消化系统的形态学和组织学结构特点。爪鲵口腔底部具有肌肉质的舌,食管很短,胃是呈纺锤形的长囊,胃壁较厚,粘膜厚,胃腺发达。消化管肌层皆为平滑肌,环肌明显多于纵肌。肝脏较大,分左、中、右三叶;有胆囊;胰腺长带状,胰管与胆管汇合后与小肠最前部的十二指肠相连。  相似文献   

8.
几种不同进化程度动物细胞内质网超微结构的比较研究   总被引:1,自引:0,他引:1  
应用稼射电镜技术,高锰酸钾固定扫描电镜技术及生化分离技术,比较研究了家兔、家鸽、蟾蜍,鲤鱼、脉红螺肝细胞和眼虫的内质网超微结构及含量。透射电镜观察结果显示:在高等哺乳动物肝细胞内质网丰富,以扁囊结构为主,在整个细胞质内均有分布,主要存在于核周围,并伴有伴随线粒体分布的特征;蟾蜍肝细胞内质网稀少,以长管状平行排列,分布在细胞质的局部,鲤鱼肝细胞内质网呈小泡状均匀分布在细胞质中,脉红螺肝细胞及眼虫细胞  相似文献   

9.
马蹄香种子生物学特性研究   总被引:3,自引:0,他引:3  
赵桦  杨培君  李会宁   《广西植物》2006,26(1):14-17
马蹄香的雌蕊子房半下位,心皮6枚,蒴果蓇葖状,果实成熟时沿腹缝线开裂。种子呈三角状倒椭圆形,其背面凸出,具明显横皱纹,腹面凹入。马蹄香种子由种皮、胚乳和胚三部分构成。种皮由多层细胞组成;核型胚乳,种子成熟时游离胚乳核形成胚乳细胞,而胚尚未分化,仍停留在原胚阶段。种子发芽试验表明,马蹄香种子萌发率极低,具有种子休眠的生物学特征。对马蹄香种子的化学成分作了分析研究,种子胚乳中富含营养物质,其中粗蛋白含量为17.3(g/100g)。此外,种子含有丰富的镁、锰、钙、铁、锌等矿质元素。  相似文献   

10.
不同风信子品种在南京地区的物候期及生长特性分析   总被引:1,自引:0,他引:1  
对从荷兰引进的17个风信子(Hyacinthus orientalis L. )品种在南京地区的物候期、观赏特性和生长状况进行了调查分析.调查结果表明,17个风信子品种的耐寒性较强,出苗期最早在1月下旬,多数品种的出苗期在2月中下旬;绝大多数风信子品种的叶片展开期集中在3月14日至20日;花现色期多为2月底至3月初,第1朵花的开花期在3月中上旬;大部分品种的单花序开花持续时间和群体开花持续时间较长,分别达20~22 d和27~31 d.17个风信子品种的花均具有非常浓烈的香味,花蕾与花脉颜色相同,花色从花脉辐射至花瓣边缘并逐渐变淡,花色艳丽, 观赏性强. 少数品种具1个花枝, 多数品种具2个花枝, 花茎长度12.7~21.9 cm, 多数品种的花茎长度在17 cm以上;主花序长度多在11 cm以上,约占整个花茎长度的2/3;单花序花朵数为20~61.各品种的花瓣数和花药数基本一致,多以6为基数;17个风信子品种的花粉均有一定的萌发能力,其中9个品种的花粉萌发率较高,均超过40%.多数品种的叶片数为6或7,叶片长18~29 cm,宽2.2~3.6 cm.除品种'阿姆斯特丹'、'简波斯'和'福特'外,其余品种均可以分生出籽球,其中,品种'蓝星'、'蓝夹克'和'爱丽斯'的籽球分生能力最强,分生率达66%以上;不同风信子品种的籽球直径也各不相同,多数籽球直径较大,为3~5 cm.结果显示,风信子可作为早春花卉在南京进行种植,但具体种植条件尚待深入研究.  相似文献   

11.
Failure of pancreatic beta-cells is the common characteristic of type 1 and type 2 diabetes. Type 1 diabetes mellitus is induced by destruction of pancreatic beta-cells which is mediated by an autoimmune mechanism and consequent inflammatory process. Various inflammatory cytokines and oxidative stress are produced during this process, which has been proposed to play an important role in mediating beta-cell destruction. The JNK pathway is also activated by such cytokines and oxidative stress, and is involved in beta-cell destruction. Type 2 diabetes is the most prevalent and serious metabolic disease, and beta-cell dysfunction and insulin resistance are the hallmark of type 2 diabetes. Under diabetic conditions, chronic hyperglycemia gradually deteriorates beta-cell function and aggravates insulin resistance. This process is called "glucose toxicity". Under such conditions, oxidative stress is provoked and the JNK pathway is activated, which is likely involved in pancreatic beta-cells dysfunction and insulin resistance. In addition, oxidative stress and activation of the JNK pathway are also involved in the progression of atherosclerosis which is often observed under diabetic conditions. Taken together, it is likely that oxidative stress and subsequent activation of the JNK pathway are involved in the pathogenesis of type 1 and type 2 diabetes.  相似文献   

12.
大黄鱼精子的超微结构   总被引:44,自引:1,他引:43  
尤永隆  林丹军 《动物学报》1997,43(2):119-126
大黄鱼的精子由头产和尾部两部分组成。头部结构较为独特,其腹侧有一较大的细胞核,背部有中心粒复合体。头部的后端是袖套。细胞核的腹面稍向外突出背面则稍向内凹。细胞核中的染以质浓缩成致密的团块状。团块状的染色质之间分布着松散的纤维状染色质。植入窝位于细胞核的背部表面,由细胞核背面向内凹陷而成,呈一沟状,其走向与精子的长轴平行。  相似文献   

13.
路娟  陈非 《生物技术》1994,4(5):34-37
药敏药片经临床对金黄色葡萄球菌、大肠埃希氏菌、铜绿假单胞菌等235株考核.表明药片工艺研究先进,药片与培养基结合牢固,无断裂、崩解,不渗出颗粒,抑菌圈呈同心园扩散.边缘清楚。药物含量均匀,释放度好。药片抑菌差仅1~3mm;而纸片抑菌差为2~12mm。药片变黑系数CV为2.71~4.21;而纸片CV为3.82~14.36。表明纸片片间差大,药片精密度明显好于纸片。  相似文献   

14.
Phylogenetic relationships within Collembola were determined through the cladistic analysis of 131 morphological characters and 67 exemplar taxa representing the major families of the group, with special emphasis on Poduromorpha. The results show that the order Poduromorpha is monophyletic and the sister group to the remaining Collembola, with Entomobryomorpha monophyletic and the sister group to the clade Neelipleona + Symphypleona. In Entomobryomorpha, Actaletidae is the sister group of the remaining families. In Poduromorpha, Tullbergiinae is monophyletic as well as Onychiurinae and the group Tetrodontophorinae + Onychiurinae which is the sister group of the remaining Poduromorpha; Tetrodontophorinae is paraphyletic; Onychiuridae is polyphyletic; Isotogastruridae is not an intermediate between Poduromorpha and Entomobryomorpha, it is the sister group of Tullbergiinae; Odontellidae is monophyletic and the sister group to the clade Neanuridae + Brachystomellidae; in Neanuridae, Frieseinae and the group Pseudachorutinae + Morulinae + Neanurinae are monophyletic; Morulinae is the sister group of Neanurinae; Pseudachorutinae is paraphyletic; Hypogastruridae is polyphyletic; Podura aquatica (Poduridae) is not 'primitive', it clusters with the genera Xenylla and Paraxenylla in Hypogastruridae. On the basis of these relationships and the position of the aquatic species, the most parsimonious hypothesis is a terrestrial edaphic origin for the springtails.  相似文献   

15.
利用石蜡切片法对中华花龟的心脏、肝脏、脾脏、肺和肾脏等组织器官进行了组织学观察.结果显示心肌的特点是暗带较窄,心肌纤维束状排列.肝脏分3叶,肝实质内结缔组织少,肝小叶分界不清楚.脾脏分被膜和实质两部分,实质由白髓和红髓构成,白髓包括椭球周围淋巴鞘(PELS)和动脉周围淋巴鞘(PALS),红髓由脾索和脾窦组成,未发现淋巴小结和生发中心.肺一对,为长形扁平囊,肺泡囊状,肺泡内可见管壁的结节状膨大.肾脏由肾小体、颈段、近曲小管、中间段、远曲小管和收集管6部分构成,肾小体由肾小球和肾小囊组成,在肾小体附近可见致密斑样结构.  相似文献   

16.
In contrast to the epidermal growth factor (EGF) receptor, ErbB2 is known to remain at the plasma membrane after ligand binding and dimerization. However, why ErbB2 is not efficiently down-regulated has remained elusive. Basically, two possibilities exist: ErbB2 is internalization resistant or it is efficiently recycled after internalization. By a combination of confocal microscopy, immunogold labeling electron microscopy, and biochemical techniques we show that ErbB2 is preferentially associated with membrane protrusions. Moreover, it is efficiently excluded from clathrin-coated pits and is not seen in transferrin receptor-containing endosomes. This pattern is not changed after binding of EGF, heregulin, or herceptin. The exclusion from coated pits is so pronounced that it cannot just be explained by lack of an internalization signal. Although ErbB2 is a raft-associated protein, the localization of ErbB2 to protrusions is not a result of raft binding. Also, an intact actin cytoskeleton is not required for keeping ErbB2 away from coated pits. However, after efficient cross-linking, ErbB2 is removed from protrusions to occur on the bulk membrane, in coated pits, and in endosomes. These data show that ErbB2 is a remarkably internalization-resistant receptor and suggest that the mechanism underlying the firm association of ErbB2 with protrusions also is the reason for this resistance.  相似文献   

17.
The first comprehensive analysis of higher‐level phylogeny of the order Hymenoptera is presented. The analysis includes representatives of all extant superfamilies, scored for 392 morphological characters, and sequence data for four loci (18S, 28S, COI and EF‐1α). Including three outgroup taxa, 111 terminals were analyzed. Relationships within symphytans (sawflies) and Apocrita are mostly resolved. Well supported relationships include: Xyeloidea is monophyletic, Cephoidea is the sister group of Siricoidea + [Xiphydrioidea + (Orussoidea + Apocrita)]; Anaxyelidae is included in the Siricoidea, and together they are the sister group of Xiphydrioidea + (Orussoidea + Apocrita); Orussoidea is the sister group of Apocrita, Apocrita is monophyletic; Evanioidea is monophyletic; Aculeata is the sister group of Evanioidea; Proctotrupomorpha is monophyletic; Ichneumonoidea is the sister group of Proctotrupomorpha; Platygastroidea is sister group to Cynipoidea, and together they are sister group to the remaining Proctotrupomorpha; Proctotrupoidea s. str. is monophyletic; Mymarommatoidea is the sister group of Chalcidoidea; Mymarommatoidea + Chalcidoidea + Diaprioidea is monophyletic. Weakly supported relationships include: Stephanoidea is the sister group of the remaining Apocrita; Diaprioidea is monophyletic; Ceraphronoidea is the sister group of Megalyroidea, which together form the sister group of [Trigonaloidea (Aculeata + Evanioidea)]. Aside from paraphyly of Vespoidea within Aculeata, all currently recognized superfamilies are supported as monophyletic. The diapriid subfamily Ismarinae is raised to family status, Ismaridae stat. nov. © The Will Henning Society 2011.  相似文献   

18.
产生复干是银杏个体发育过程中一个普遍现象。本研究以临沂生生园全国最大复干银杏群落为对象,采用每木检尺的方式对园内复干银杏进行调查。结果显示,生生园内银杏共385株,雌株379株,占98.41%;平均树高20.9m,总胸径0.93m,母干胸径0.33m,冠径在5.0-15.0m范围内,枝下高6.3m;17株无复干,复干率为98.58%,每株复干数平均为4.6个,最大复干高为12.5m,胸径0.18m,复干与母干距离为0.61m,复干与母干夹角为10.5?;34株无萌蘖,萌蘖平均株数为38株,萌蘖高1.11m,萌蘖与母干最大距离0.73m。该片银杏林原桩有240年历史,现存复干银杏系从原桩萌发形成,树龄53年。本文对生生园复干银杏的起源、性别比例、复干与银杏适应性的关系等进行了探讨。  相似文献   

19.
蓝翅希鹛消化系统的初步研究   总被引:4,自引:0,他引:4  
于德芳  郭延蜀 《四川动物》2007,26(4):919-922,F0003
对6只(3♀,3♂)蓝翅希鹛的消化系统进行了解剖观察,结果表明:蓝翅希鹛的舌成细长三角形,雌、雄舌尖端差异显著:雌鸟舌尖端各有一根长刺毛,而雄鸟无此长刺毛;在舌前端正中央还有一"v"形的凹缺,使舌成二分叉,雌鸟分叉深约2.77 mm,雄鸟为1.63 mm。食道颈胸部分段不明显,食管长18.64~23.55 mm,嗉囊外观不明显。腺胃乳突短而小,分布均匀;肌胃发达,具角质膜。肠道长与体长基本相等,小肠较发达,雌鸟长100.90 mm,占肠道总长90.08%,雄鸟分别为102.52 mm和89.60%;具有双侧盲肠,但不发达,占肠道总长的2.3%~2.8%,右侧盲肠略大于左侧;直肠短,雌鸟仅占肠道8.55%,雄鸟占8.72%。肝为体内最大的消化腺,分左右两叶。胰位于十二指肠袢内,细长形,分二小叶。由消化道特征说明其食性是以食虫为主的杂食性鸟类。  相似文献   

20.
L-Cysteinesulfonate (L-cysteate) is present in plasma, urine, and tissues in concentrations comparable to that of L-cysteinesulfinate, the primary oxidative metabolite of L-cysteine. Although cysteinesulfonate is known to be decarboxylated to taurine by cysteinesulfinate decarboxylase, the occurrence and importance of other metabolisms has not been examined. The present studies indicate that cysteinesulfonate partitions in vivo between decarboxylation and transamination; the latter reaction is catalyzed by aspartate aminotransferase and yields beta-sulfopyruvate. Whereas beta-sulfinylpyruvate, the product of cysteinesulfinate transamination, decomposes spontaneously, beta-sulfopyruvate is stable and is reduced by malate dehydrogenase to beta-sulfolactate. When L-[1-14C]cysteinesulfonate is given to mice, 60-75% is decarboxylated to taurine and about 25% is excreted in the urine as beta-sulfolactate. beta-Sulfo[1-14C] pyruvate is found to partition about equally between beta-sulfolactate and cysteinesulfonate formation; greater than 90% of the latter is decarboxylated. Parenterally administered beta-sulfo[1-14C]lactate is mostly excreted in the urine, but 12% is metabolized via beta-sulfopyruvate and cysteinesulfonate to 14CO2 and taurine. beta-Sulfopyruvate is not excreted, and only traces of sulfoacetate, perhaps formed by oxidative decarboxylation, are detected. These studies establish that cysteinesulfonate, beta-sulfopyruvate, and beta-sulfolactate are reversibly interconverted in vivo. Since only cysteinesulfonate is directly metabolized to CO2, the rate of 14CO2 formation from L-[1-14C]cysteinesulfonate is a valid measure of total cysteinesulfinate decarboxylase activity in vivo; use of this assay permits inhibitor effects to be accurately determined in intact mice. Thus, whereas in vitro assays indicate that beta-methyleneaspartate inhibits brain, liver, and kidney cysteinesulfinate decarboxylase by 0, greater than 60, and 90%, respectively, in vivo studies with L-[1-14C]cysteinesulfonate show net metabolic inhibition is about 40%.  相似文献   

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