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1.
安徽黄精属植物花粉形态的研究   总被引:12,自引:0,他引:12  
郑艳  孙叶根 《植物研究》1998,18(4):414-417
利用光学显微镜及扫描电子显微镜对安徽省所产七种黄精属植物进行了花粉结构观察。结果表明,黄精属植物花粉形态较为一致,均属两侧对称;形状上多为船形,大小为(21.5-57.9)×(18.9-31.0)μm,具远极单沟,沟长,花粉外壁两层红等中外层略厚,或内层略层;外壁具微穿孔纹饰,穿孔大小、形状均不规则。主张在进行黄精属种间区分时,应考虑花粉外壁的某些特点。  相似文献   

2.
国产省藤属植物的花粉形态学   总被引:2,自引:1,他引:1  
对国产棕榈科省藤属(Calamius L.)15种植物的花粉进行了光学和扫描电镜观察,其中12种为首次报道。省藤属的花粉均为两沟型花粉,外壁覆盖层多为网状纹饰(大喙省藤C.macrorrhynchus)或具穿孔(华南省藤C.rhabdocladus)。首次发现省藤属花粉的外壁纹饰存在穿孔和外壁疣状突起的类型(阔叶鸡藤C.pulchellus)以及皱波状突起的类型(长鞭省藤C.flagellum)。花粉的大小、形状、外壁纹饰、外壁是否有突起,外壁厚度和网状纹饰网眼的大小,对于省藤属的种级分类有较大的意义。  相似文献   

3.
金花茶组植物花粉扫描电镜研究(一)   总被引:11,自引:0,他引:11  
植物花粉的形态特征具有种属特异性。本文用扫描电子显微镜报道了金花茶组8种植物花粉的形态特征。结果表明,8种金花茶组植物的花粉外壁纹饰可分为三大类型:疣状纹饰(块状纹饰)类型、脑纹状纹饰(蠕虫状纹饰)类型及拟网状纹饰类型。不同种植物花粉外壁纹饰存在一定差异,三大类型花粉外壁纹饰存在一定的演化关系,可为种间分类及演化关系提供依据。  相似文献   

4.
对中国苦苣苔科异片苣苔属、长檐苣苔属和报春苣苔属等3个特有属中3种代表植物的花粉形态进行了光镜和扫描电镜的观察。结果发现这些植物的花粉形状比较一致,均为长球形或近球形,表明花粉形状对苦苣苔科的系统与分类没有太大的参考价值。观察到两种类型的花粉外壁纹饰:细网状纹饰、粗网状纹饰;异片苣苔属具粗网状纹饰,长檐苣苔属和报春苣苔属具细网状纹饰。还讨论了一些花粉外壁纹饰特征在苦苣苔科的系统研究方面的潜在价值。  相似文献   

5.
刘林  张良英  程贵兰  何丹  张力飞  孟凡丽 《广西植物》2022,42(10):1675-1683
采用扫描电镜法,观察和比较了西藏色季拉山10种报春花的花粉形态特征,同时进行聚类分析,以期为该属植物分类提供孢粉学证据,并进一步为西藏报春花属植物杂交育种及种质资源的利用提供参考。结果表明:(1)供试10种报春花属植物的花粉形状为扁球形、近球形,其中,工布报春(Primula kongboensis)的花粉粒最小,暗紫脆蒴报春(P.calderiana)的花粉粒最大,西藏报春(P.tibetica)为多沟型花粉,其余报春花的花粉一般具3孔沟,大部分孔沟在极区汇合形成复合沟。(2)花粉外壁纹饰大多为穴状或网状,其中,中甸灯台报春(P.chungensis)和西藏报春为网状纹饰中的粗网状类型。(3)虽然基于花粉形态的聚类分析与植物学分类表现出一定的一致性,但粉报春组的西藏报春和工布报春则由于在孢粉学特征上具有明显差异,因此保持了相对较远的亲缘关系。该研究初步认为,色季拉山10种报春花粉形态存在种间差异,研究结果可为植物分类提供一定的参考依据。然而,在进行分类时,仍然需要结合形态学特征、分子生物学等方面综合考虑。  相似文献   

6.
采用光学显微镜和扫描电镜对产自安徽省大别山金缕梅科银缕梅(Parrotia subaequalis)的花粉进行了观察和研究。银缕梅花粉粒近球形或长球形,P/E(极轴/赤道轴)=1.27(1.14-1.32),赤道面观椭圆形,极面观圆三角形或三裂圆形,大小为37.3(32.0~41.0)×29.4(25.0~36.0)μm。具3沟,沟狭长,几达两极。花粉外壁厚2.0~2.4μm,外层与内层近等厚,柱状层基柱发达。外壁纹饰在光镜下为细网状,在扫描电镜下为粗网状纹饰,网脊上有刺瘤。现生银缕梅具有鲜明的生境和分布格局特点,本研究为利用地层中银缕梅化石花粉重建古环境、古气候等提供了现代孢粉学参考依据,也为研究金缕梅科的起源、演化和现代地理分布提供了科学依据。  相似文献   

7.
通过开展山茶属连蕊茶组(Camellia Sect. Theopsis)和毛蕊茶组(Camellia Sect. Eriandria)的花粉形态研究,为2组植物的系统演化、分类鉴定等提供一定的参考依据。以2组植物的20种(变种)材料为研究对象,进行花粉形态的扫描电镜观察。结果显示:(1)20种连蕊茶组和毛蕊茶组植物主要为中等花粉(25~50μm)和大花粉(50~100μm),花粉极面观为三裂圆形,赤道面观为长球形,萌发孔类型为3孔沟型。(2)花粉的外壁纹饰主要包括孔穴状、疣状和颗粒状3种纹饰类型,长管连蕊茶(C. elongata)为孔穴状纹饰,蒙自连蕊茶(C. forrestii)和尖萼蒙自连蕊茶(C. forrestii var. acutisepala)为疣状纹饰,其余17种(变种)均为颗粒状纹饰。研究推测2组植物花粉外壁纹饰的演化趋势为孔穴状→颗粒状→疣状。花粉的形态特征支持连蕊茶组和毛蕊茶组植物为单系类群的观点,但作孚连蕊茶(C. tsofuii)和荔波连蕊茶(C. lipoensis)作为变种的分类观点有待进一步研究探讨。  相似文献   

8.
用扫描电子显微镜对中国鸡矢藤属(Paederia L.)6种1变种植物的花粉进行观察。结果表明:鸡矢藤属植物的花粉均为单粒,辐射对称,小型或中型,极面观3-裂圆形至钝三角形,赤道面观呈长圆球形或近长球形,具3个萌发沟,无内萌发孔。外壁纹饰网状、细网状或穿孔状,孔边缘具小刺状突起或无。臭鸡矢藤(P.foetida)和白毛鸡矢藤(P.pertomentosa)具有花粉二型现象,其中白毛鸡矢藤(P.pertomentosa)是首次报道。花粉二型现象与花柱二型现象可能没有直接的关联性,与前人的观点一致。推测鸡矢藤属外壁纹饰的可能演化趋势为:穿孔、网状、细网状→粗网状;网眼内无棒状突起→网眼内有棒状突起。鸡矢藤属花粉的外壁纹饰变化较大,且无内萌发孔,是茜草科花粉过渡类型的特征。  相似文献   

9.
在扫描电子显微镜下,对豆科土儿属(Ap ios)和旋花豆属(Coch lianthus)7个种植物的花粉进行了观察.结果表明,2个属的花粉均为三孔沟,形状为三角球形或球形.土儿属的花粉可划分为2种类型:肉色土儿(A.carnea)的花粉外壁为典型的网状纹饰,其它种的花粉外壁较光滑,具颗粒状或短条纹状纹饰,研究结果不支持土儿属下亚属的划分;肉色土儿花粉外壁的网状纹饰式样可能反映了其在土儿属中处在较进化的位置.土儿属东亚分布种的花粉类型较为多样,原始和进化2种类型并存,表明东亚可能是土儿属的起源地和演化中心.旋花豆属的花粉特征和肉色土儿相似,说明两者之间的亲缘关系可能较近.  相似文献   

10.
广西苦苣苔科植物花粉形态   总被引:3,自引:0,他引:3  
曹明  林春蕊  唐赛春  韦毅刚 《广西植物》2003,23(2):139-T004
对广西苦苣苔科(Gesneriaceae)8个属(1个特有属)11个种(8个特有种)的花粉形态进行了扫描电镜的观察。结果发现这些不同属种的花粉形状均为长球形或近球形,花粉形状对苦苣苔科的系统与分类没有多大的参考价值。但花粉外壁纹饰则有多种类型。其中,吊石苣苔属(Lysionotus)、金盏苣苔属(I sometrum)、长檐苣苔属(Dolicholoma)、紫花苣苔属(Loxostigma)、半蒴苣苔属(Hemiboea)、圆唇苣苔属(Gy rocheilos)及唇柱苣苔属(Chirita)中的百寿唇柱苣苔(C.baishouensis)为网状纹饰;唇柱苣苔属(Chirita)的桂林唇柱苣苔(C.gueilinensis)和融安唇柱苣苔(C.ronganensis)为拟网状纹饰;异唇苣苔属(Allocheilos)为脑纹状纹饰。孢粉学特征表明,花粉外壁纹饰特征在苦苣苔科的分类与系统研究方面可能具有较大价值。  相似文献   

11.
The ATP/ADP exchange is shown to be a partial reaction of the (H+ + K+)-ATPase by the absence of measurable nucleoside diphosphokinase activity and the insensitivity of the reaction to P1, P5 -di(adenosine-5′) pentaphosphate, a myokinase inhibitor. The exchange demonstrates an absolute requirement for Mg2+ and is optimal at an ADP/ATP ratio of 2. The high ATP concentration (K0.5 = 116 μM) required for maximal exchange is interpreted as evidence for the involvement of a low affinity form of nucleotide site. The ATP/ADP exchange is regarded as evidence for an ADP-sensitive form of the phosphoenzyme. In native enzyme, pre-steady state kinetics show that the formation of the phosphoenzyme is partially sensitive to ADP while modification of the enzyme by pretreatment with 5,5′-dithiobis(2-nitrobenzoic acid) (DTNB) in the absence of Mg2+ results in a steady-state phosphoenzyme population, a component of which is ADP sensitive. The ATP/ADP exchange reaction can be either stimulated or inhibited by the presence of K+ as a function of pH and Mg2+.  相似文献   

12.
目的甲型H1N1流感病毒A/California/7/2009与A/California/4/2009病毒序列比较同源性在99%以上,本实验旨在比较两株病毒感染BALB/c小鼠研究感染力强弱。方法分别将A/California/7/2009(CA7)与A/California/4/2009(CA4)两株病毒分别连续10倍稀释后,对4~6周龄雌性BALB/c小鼠经乙醚麻醉后进行滴鼻攻毒,每个稀释度接种10只实验小鼠,测定CA7 MLD50为101.24/0.05 mL,检测小鼠感染、致病的多项指标,观察期为14 d。结果相同TCID50的CA7和CA4病毒感染小鼠,CA4感染小鼠后14 d内死亡率为20%,而CA7感染小鼠后8 d内死亡率为100%。CA7 106TCID50感染的小鼠病理表现为重度弥漫性间质性肺炎,CA4 106TCID50感染的小鼠病理表现为中度-重度间质性肺炎。结论在相同条件下,CA7感染力明显强于CA4。  相似文献   

13.

Background  

Assignment of function to new molecular sequence data is an essential step in genomics projects. The usual process involves similarity searches of a given sequence against one or more databases, an arduous process for large datasets.  相似文献   

14.
The parameters estimated from traditional A/C i curve analysis are dependent upon some underlying assumptions that substomatal CO2 concentration (C i) equals the chloroplast CO2 concentration (C c) and the C i value at which the A/C i curve switches between Rubisco- and electron transport-limited portions of the curve (C i-t) is set to a constant. However, the assumptions reduced the accuracy of parameter estimation significantly without taking the influence of C i-t value and mesophyll conductance (g m) on parameters into account. Based on the analysis of Larix gmelinii’s A/C i curves, it showed the C i-t value varied significantly, ranging from 24 Pa to 72 Pa and averaging 38 Pa. t-test demonstrated there were significant differences in parameters respectively estimated from A/C i and A/C c curve analysis (p<0.01). Compared with the maximum ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylation rate (Vcmax), the maximum electron transport rate (Jmax) and Jmax/Vcmax estimated from A/C c curve analysis which considers the effects of g m limit and simultaneously fits parameters with the whole A/C c curve, mean Vcmax estimated from A/C i curve analysis (Vcmax-C i) was underestimated by 37.49%; mean Jmax estimated from A/C i curve analysis (Jmax-C i) was overestimated by 17.8% and (Jmax-C i)/(Vcmax-C i) was overestimated by 24.2%. However, there was a significant linear relationship between Vcmax estimated from A/C i curve analysis and Vcmax estimated from A/C c curve analysis, so was it Jmax (p<0.05).  相似文献   

15.
Purified cytochrome P450SCC from bovine adrenocortical mitochondria was incorporated into liposomes by the cholate-dilution method utilizing either dialysis or Sephadex gel filtration. Among synthetic phospholipids tested, dioleoylglycerophosphocholine showed the best stability during the incorporation of P450SCC into liposomes. A maximum amount of heme was incorporated into liposomes at a molar ratio of phospholipid to the cytochrome of approx. 200. When P450SCC was incorporated into the dioleoylglycerophosphocholine liposomes by the cholate-filtration method, the P450SCC-containing liposomes showed two major populations on the elution pattern of the Sepharose 4B gel filtration, and were seen at a diameter of 200–600 Å and its aggregated forms. When the cytochrome was incorporated into dioleoylglycerophosphocholine liposomes or cholesterol-free adrenocortical mitochondrial liposomes, P450SCC was less stable than P450SCC in aqueous solution. Cholesterol or adrenodoxin markedly stabilized the liposomal P450SCC. Liposomal P450SCC required cholesterol for its optimum reduction with adrenodoxin, adrenodoxin reductase, and NADPH in the presence of CO. About 70% of the total heme in the dioleoylglycerophosphocholine liposomes was reduced by the enzymatic reduction in the presence of cholesterol, indicating that 70% of the total molecules are exposed to the surface of the outer monolayer. In order to see the location of the heme in membrane, the dioleoylglycerophosphocholine-liposomal P450SCC was subjected to p-chloromercuriphenyl sulfonic acid treatment. This reagent destroyed the liposomal P450SCC. These results suggest that the heme is located in the proximity of the p-chloromercuriphenyl sulfonic acid reacting sites which are exposed to the surface, or located on the vincinity of polar heads of the membrane.  相似文献   

16.
The partial purification of (Na+ + K+)-ATPase from pig lens has been achieved by treatment with deoxycholate followed by density gradient centrifugation. The specific activity of the final preparation, ranging from 300 to 500 nmol/h per mg protein, is increased approx. 100-fold compared to the homogenate. A parallel increase in p-nitrophenylphosphatase activity is also observed. Sodium dodecyl sulfate (SDS) gel electrophoresis reveals six major protein bands, one of which is the 93 kDa α subunit of (Na+ + K+)-ATPase which can be phosphorylated by reaction with [γ-32P]ATP. A second band contains a glycoprotein which displays an apparent molecular weight of 51 000 and thus appears to be the β subunit of the enzyme. The enzyme is sensitive to ouabain with the I50 for (Na+ + K+)-ATPase and p-nitrophenylphosphatase inhibition being 1.2 and 1.3 μM, respectively. Several agents which inhibit Na+ + K+)-ATPase from other tissues such as oligomycin, Ca2+, vanadate, N-ethylmaleimide, p-chloromercuribenzenesulfonic acid (PCMBS) and 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) also inhibit the lens enzyme. Monovalent cations other than K+ are partially effective in activating the (Na+ + K+)-ATPase and p-nitrophenylphosphatase activities. The K+ congeners were relatively more effective in supporting (Na+ + K+)-ATPase compared to p-nitrophenylphosphatase activity. Other kinetic properties of the lens enzyme are also comparable to those of the enzyme from other tissues. Utilizing the partially purified membrane bound enzyme, discontinuities in Arrhenius plots of (Na+ + K+)-ATPase activity, p-nitrophenylphosphatase activity and fluoresence polarization of the fluidity probe, 1,6-diphenyl-1,3,5-hexatriene (DPH), are observed near the physiological temperature of lens. The possible significance of these observations for the mechanism of cataract formation are discussed.  相似文献   

17.
The modulating effect of membrane lipids on enzyme function has been described by several investigators. We have used the spin probe N-oxyl-4′,4′-dimethyloxazolidine-12-keto methyl stearate (M 12-NSE) to study this interaction in ox brain membranes enriched with (Na+ + K+)-ATPase. This methyl ester of stearic acid is practically insoluble in aqueous media, and consequently spectra of M 12-NSE-labelled preparations are free of “liquid lines”.At least two types of spectra may be obtained when ox brain microsomes are spin labelled with M 12-NSE, indicating the presence of two distinct binding sites. At one site the spin label is relatively unrestricted and gives rise to an isotropic spectrum. A second spectrum, which is obtained from spin label at another site, is similar to that which is observed after incorporation of M 12-NSE into phospholipid bilayers. This suggests that this latter site is within the core of the microsomal membrane.The two binding sites differ in their affinity for the spin probe. The low affinity site is both more abundant in crude preparations and is more easily removed by detergent treatment; spin labels at this site produce isotropic spectra. The high affinity sites are fewer in number and produce broad spectra. In addition these high affinity sites increase in concentration as the enzyme undergoes purification.The two sites are quite distinct in their sensitivity to ascorbic acid, the low affinity site showing a considerably greater rate of reduction by this agent.This study also demonstrates that the delipidation effects of sodium dodecyl sulfate and sodium deoxycholate on (Na+ + K+)-ATPase-enriched microsomes from ox brain are not identical.It is suggested that the two spin probe binding sites represent two different lipid domains, one of which is very closely associated with the (Na+ + K+)-ATPase enzyme and may reflect a protein-directed phospholipid specificity for this enzyme.  相似文献   

18.
Showdomycin inhibited pig brain (Na+ + K+)-ATPase with pseudo first-order kinetics. The rate of inhibition by showdomycin was examined in the presence of 16 combinations of four ligands, i.e., Na+, K+, Mg2+ and ATP, and was found to depend on the ligands added. Combinations of ligands were divided into five groups in terms of the magnitude of the rate constant; in the order of decreasing rate constants these were: (1)Na+ + Mg2+ + ATP, (2) Mg2+, Mg2+ + K+, K+ and none, (3) Na+ + Mg2+, Na+, K+ + Na+ and Na+ + K+ + Mg2+, (4) Mg2+ + K+ + ATP, K+ + ATP and Mg2+ + ATP, (5)K+ + Na+ + ATP, Na+ + ATP, Na+ + ATP, Na+ + K+ + Mg2+ + ATP and ATP. The highest rate was obtained in the presence of Na+, Mg2+ and ATP. The apparent concentrations of Na+, Mg2+ and ATP for half-maximum stimulation of inhibition (K0.5s) were 3 mM, 0.13 mM and 4μM, respectively. The rate was unchanged upon further increase in Na+ concentration from 140 to 1000 mM. The rates of inhibition could be explained on the basis of the enzyme forms present, including E1, E2, ES, E1-P and E2-P, i.e., E2 has higher reactivity with showdomycin than E1, while E2-P has almost the same reactivity as E1-P. We conclude that the reaction of (Na+ + K+)-ATPase proceeds via at least four kinds of enzyme form (E1, E2, E1 · nucleotide and EP), which all have different conformations.  相似文献   

19.
One of the ninhydrin-negative alanine conjugates isolated from pea seedlings was identified as N-malonyl-D-alanine.The identification of this conjugate was carried out by a comparison of its gas-liquid chromatographic and mass spectrometric properties, and its nuclear magnetic resonance and infrared spectra with those of synthetic N-malonyl-D-alanine. The alanine in the conjugate was shown to be present as the D-isomer by enzymatic and chromatographic analyses.  相似文献   

20.

Background  

Risk for complex disease is thought to be controlled by multiple genetic risk factors, each with small individual effects. Meta-analyses of several independent studies may be helpful to increase the ability to detect association when effect sizes are modest. Although many software options are available for meta-analysis of genetic case-control data, no currently available software implements the method described by Kazeem and Farrall (2005), which combines data from independent family-based and case-control studies.  相似文献   

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