高亏格膜泡形状

溶液中流体相磷脂膜泡的平衡形状是由其弯曲弹性能决定的。我们用Surface Evolver软件找到了一个具体的模拟稳定膜泡形状的方法,对亏格为2的膜泡进行了研究。我们提供了具体的计算结果。     

球形拓扑下对budding和multi-budding生物膜泡形状的研究

流体相磷脂双分子层在水溶液中能自组织的形成球形拓扑的膜泡,膜泡的平衡形状是由其弯曲弹性能决定的.Budding是流体相磷脂双分子膜泡的一个显著的形状.从自发曲率(SC)模型的弯曲能量和双层(BC)模型的弯曲能量在参数替换情况下,我们看到自发曲率(SC)和双层(BC)模型具有相同的形状方程.本文从双层(BC)模型的相图出发,在双层(BC)模型下,通过建立一些与目标形状相近似的初始形状,在面积A,体积V和平均曲率的积分M的约束条件和使用约化量的情况下,经Surface Evolver软件的逐次细分并长时间演化,得到了一些budding和multi-budding型的生物膜泡形状.     

开口膜泡形状的研究

本文报道了最近在开口膜泡研究方面的一些理论和实验进展,给出了开口膜泡的形状方程和边界条件及稳定开口膜泡的形状及其相图,并对该领域的研究存在的问题与研究趋势进行了分析.     

数值解法研究生物膜泡形状

目的:研究生物膜泡的可能形状.方法通过数值解法中的打靶法,运用Mathematica软件进行编程.结果:获得与Udo Seifert计算基本相符的图,得到了相应的生物膜泡形状,包括双凹圆盘,长椭球和扁椭球等,且获得了新的形状.结论:本法提供了一种相对精确的寻找膜泡的方法.     

小约化体积膜泡形状的研究

目的:研究ADE模型下小约化体积膜泡的形状。方法:应用数值计算方法中的打靶法,运用Mathematica 7.0软件进行编程。结果:在ADE模型下,计算得到了一系列小约化体积的膜泡的形状,解决了已往小约化体积区域内不存在稳定膜泡的问题。结论:研究表明,在ADE模型下通过适当的边界条件把黏附双层区域的接触势能考虑进去,数值计算结果与实验上的非常相似。     

SC模型小约化体积膜泡的形状方程的研究

目前还没有相关文献报道在自发曲率模型下探究小约化体积形状方程以及边界条件.本文应用标准的变分法,在自发曲率模型下推导了旋转轴对称情况下的小约化体积膜泡的形状方程以及讨论了相应的边界条件.我们相信数值求解该模型下的形状方程和边界条件依然会得到与实验上观察一致的膜泡.     

细胞内膜泡运输中拴系因子的功能

膜泡运输是不同细胞器间进行物质传递的基本方式,分为4个重要步骤：囊泡的出芽、转运、拴系和融合。在此过程中,有许多相关因子参与调控,如包被蛋白、Rab蛋白、拴系因子、SM蛋白和SNARE等。拴系因子在运输囊泡和靶位膜发生接触的最初阶段起重要调控作用,多数拴系因子形成大的多亚基复合体发挥功能。目前,关于拴系因子的功能已经有了一定的了解,在此,我们对酵母、哺乳动物以及植物细胞中的已知拴系因子的特点和功能进行了概述。     

SM蛋白在膜泡运输中的功能

大多数细胞内都包含靶向不同细胞器的各种运输囊泡,其运输机制在进化上是高度保守的。Sec1/Munc-18(SM)蛋白在膜泡运输中起着重要的调控作用,它能够与SNARE(Soluble N-ethylmaleimide-sensitive factorattachment protein receptor)蛋白结合,共同在细胞内各个膜融合发生部位发挥重要作用。SM蛋白和SNARE复合体中的Syntaxin蛋白结合,调节SNARE复合体的装配,并与SNARE协同作用促进整个膜融合过程。文章对SM蛋白在结构和功能分析方面的最新研究进展进行了概述。     

拟南芥SNARE因子在膜泡运输中的功能

高等植物细胞含有复杂的内膜系统,通过其特有的膜泡运输机制来完成细胞内和细胞间的物质交流。膜泡运输主要包括运输囊泡的出芽、定向移动、拴留和膜融合4个过程。这4个过程受到许多因子的调控,如Coat、SM、Tether、SNARE和Rab蛋白等,其中SNARE因子在膜融合过程中发挥重要功能。SNARE因子是小分子跨膜蛋白,分为定位于运输囊泡上的v-SNARE和定位于靶位膜上的t-SNARE,两类SNARE结合形成SNARE复合体,促进膜融合的发生。SNARE蛋白在调控植物体生长发育以及对外界环境响应等生理过程中起重要作用。该文对模式植物拟南芥（Arabidopsis thaliana）SNARE因子的最新细胞内定位和功能分析等研究进展进行了概述。     

花粉形态计算机量化分析研究

以白莲花粉为实验材料,介绍了进行花粉形态计算机量化分析的步骤。花粉经醋酸法处理后,用电子显微镜对花粉进行观察照相,尔后用计算机技术对花粉电镜照片进行处理,最后用C语言编制了计算花粉形态面积的计算机程序。结果表明：花粉计算机量化分析有助于快速定量测定有关花粉形态指标,是花粉数量分类的一种有效方法。     

A Study on the Genus Acidosasa of Bambusoideae

The genus Acidosasa was published by the present authors in 1979. It only had one species at that time, Acidosasa chinensis C. D. Chu et C. S. Chao. Since then species number of the genus steadily increases. The authors have rather comprehensively studied this genus and its related genera for F1. Reip. Pop. Sin. The present paper deals mainly with morphological characteristics of the genus Acidosasa and the differences from its related genera i. e. Arundinaria, Sasa and Indosasa. The genus Acidosasa is closely related to the genus Arundinaria in the type and origin of inflorescences and the vegetative appearance. But it differs from Arundinaria in the structure of florets. In Acidosasa, each floret is provided with six stamens, while in Arundinaria each floret is of only three stamens. The genus Acidosasa is similar to the genera Indosasa and Sasa in the numbers of stamens, but it is distinguished from lndosasa by its semelauctant (determinate) inflorescence, not iterautant (indeterminate) one, from Sasa by its taller stature and branch complement with three branches. We have carefully examined all the type specimens of Acidosasa and its related genera. A conclusion reached is that there are six species in the genus Acidosasa, most of which are native to S. China, with only one species in Viet Nam. Five specific binomials are reduced and one species is transferred into this genus. Two keys to species, respectively based on the flowering and vegetative characters, are given as follow: Key to species of the genus A cidosasa (1)(based on the flowering state) 1. Lemmas glabrous. 2. Spikelets stout, 3-6mm broad, pedicels 1.5-4cm long; lemmas large, 1.5-2.2cm long, with 15-19 nerves, subcoriaceous, not glaucous, shiny. 3. Lemmas up to 2.2cm long with conspicuously transverse veinlets, tessellate; palea and rhachilla entirely. glabrous, lodicules elliptic-lanceolate, glabrous ... 1. A. chinensis 3. Lemmas 1.5-1.8cm. long, slightly tessellate; palea puberulous at apex of carina, rhachilla puberuous at apex, lodicules obovate, ciliate at apex ............ 2. A. brilletii 2. Spikelets rather slende, 2-4mm broad, pedicels 0.5-1cm long; lemmas small, about 1.3 cm long, with 7-13 nerves, more or less glaucous .......... 3. A. chienouensis 1. Lemmas pubescent. 4. Glumas and lemmas densely pubescent ........................ 4. A. hirtiflora 4. Glumas subglabrous, lemmas sparsely pubescent. 5. Spikelets large, 3-7 cm long, lemmas 1.6-1.7 cm long, pedicels 2-13 mm long ................................................. 5. A. longiligula 5. Spikelets small, 2-3.7 cm long, lemmas about 1.3 cm long, pedicels 1-3 cm long ................................................... 6. A. venusta Key to species of the genus A cidosasa (2) (based on the vegetative state) 1. Ligules of leaf-sheaths strongly elevated, usually 2-8 mm long. 2. Young culms with bristly sheath scars; culm-sheaths without auricles and oral setae, not spotted, sheath-blades erect ................. 4. A. hirtiflora 2. Young culms with glabrous sheath scars; culm-sheaths with small auricles and oral setae, sparsely spotted, sheath-blades reflexed .......... 5. A. longiligula 1. Ligules of leaf-sheaths inconspicuous, less than 2 mm long. 3. Young culms more or less bristly, or sheath-scars bristly: 4. Culm-sheaths without auricles and oral setae, not farinose, without hairs at base. 5. Young culms densely bristly; culm-sheaths attenuate at apex and as wide as sheath-blades, with conspicuously transverse veinlets; leaf-blades large, usually 2.5-3.5 (-6.5) cm broad, conspicuously tessellate ..................................................... 1. A. chinensis 5. Young culms sparsely bristly; culm-sheaths truncate at apex and broader than sheath-blades, without transverse veinlets or inconspicuous; leaf-blades small, 1.5-2.5 cm broad, without visible transverse veinlets .................................................... 6. A. venusta 4. Culm-sheaths with auricles and oral setae, slightly farinose, densely bristle at base; leaf-blades rather narrow, 0.8-1.8 cm broad ............ 3. A. chienouensis 3. Young culms entirely glabrous; leaf-blades rather narrow, 1.2-1.8 cm broad ....................................................................................... 2. A. brilletill     

A Study on Karyotypes of the Genus Lycoris

The genus Lycoris (Amaryllidaceae) consists of about 20 species, all of which are confined to temperate China, Japan and Korea. Cytological investigations, including a reexamination of the karyotypes of 14 taxa, measurements of relative nuclear DNA content, and meiotic configuration observations on some specific forms and interspecific hybrids, have been carried out by the present authors in order to re-evaluate the mode of karyotype evolution and the role of hybridization in the speciation of Lycoris. These have resulted in a new theory for explaining the karyotype evolution in the genus, which will be considered elsewhere. The present paper deals with observations on karyotypes of 11 species, 1 variety and 2 artificial hybrids. Results obtained through karyotype analysis, as shown by the data in Table 1, Plates I-VI and Figs. 1-2, reveal that: (1) the karyotypes of Lycoris rosea, L. radiata var. pumila, L. sprengeri, L. haywardii, L. caldwellii, L. squamigera and L. radiata are, on the whole, consistent with those reported by the previous authors^{[1,2,3,4,5,8,10,12]};(2) the I (rodshaped) chromosomes of L. chinensis and L. longituba are all T’s (telocentric) instead of t’s (acrocentric) or t(Sat)’s; (3) the three materials of L. aurea of different sources have shown a karyotypic differentiation: one with 2n=14=8m+6T, and the others with 2n=16=6m+10T: (4) both of the karyotypes of L. straminea and L. albiflora are 2n=19=3V+6I, inconsistent with 2n=16=6V+10I for the former and with 2n=17=5V+12I for the latter as reported by Inariyama (1953), Bose and Flory (1963) and Kurita (1987). The following aspects are worthwhile discussing: 1. The types of chromosomes. Karyotype analyses reveal the existence of three major chromosome types in Lycoris: (1) m (metacentric) chromosomes: (2) t (acrocentric) chromosomes, with short arms, (3) T (telocentric) chromosomes, sometimes with dot-like terminal centromeres. To distinghish t’s from T’s is of paramount importance for solving the problem of karyotype evolution in Lycoris. Bose (1963) pointed out that in the species with 2n=22, all I chromosomes were t’s, while in species with 2n=12-16, all I chromosomes were T’s. Our results of chromosome observations are consistent with Bose’s remarks. Some authorst^[3,6] have probably mistaken the dot-like terminal centromeres of T’s of L. longituba and L. chinensis as the short arms of t’s. 2. The significance of Robertsonian change in karyotype evolution. Although chromosome numbers and karyotypes are very variable in Lycoris, as shown in Table 1, the total number of arms of a chromosome complement of any species is always multiples of 11. Hence, it seems likely that Robertsonian changes have taken part in karyotype alteration, The genus has a series of basic chromosome numbers: 6, 7, 8 and 11. But which is the most primitive one? It is uncertain whether a successive decrease in chromosome numbers as a result of Robertsonian fusion or a gradual increase in chromosome numbers brought about by fission (fragmentation) has been the essential mechanism for karyotype evolution and speciation in Lycoris. These problems are of crucial importance and will be discussed in our subsequent papers. 3. The origin of polyploids. As evident from Table 1, there are two levels of ploidy differentiation in Lycoris: (1) di ploids with 2n=22 or the equivalent of 22, (2) triploids with 2n=33 or the equivalent of 33. The most common way of origination of triploids in plants is the hybridization of diploids with Tetraploids. But tetraploids have never been found in Lycoris. Thus, it is suggested that the triploids have originated from the combination of an unreduced gamete of a diploid with a normal gamete of another diploid. 4. The role of hybridization in speciation. Results of karyotype analyses show that hybridization has taken an important part in the speciation of Lycoris. Two types of hybrids have been found: (1) 2n=19= 3V+ 16I, L. straminea, L. albiflora and the two artificial hybrids L. sprengeri×L. chinensis and L. haywardii× L. chinensis all possess this karyotype. It could be seen from the above chromosome number and karyotype that this sort of karyotype is exactly half of the total sum of 2n=22I and 2n=16= 6V+10I. It is, therefore, quite evident that taxa possessing this karyotype are all diploid hybrids of 2n=22 and 2n=16, (2) 2n=27=6V+21I, L. caldwellii and L. squamigera possess this karyotype. It is reasonable to assume, too, that they are segmental allotriploids and have arisen from the combination of an unreduced diploid gamete of 2n=16 and a normal haploid gamete of 2n=22. The origin of the hybrid karyotype 2n=17=5V+12I reported by Inari- yama (1953) is similar to that of 2n=19, except that one of the parents possesses 2n=12= 10V+2I instead of 2n=16=6V+10I. The origin of the other hybrid karyotype 2n=30=3V+ 27I reported by Bose (1963) is similar to that of 2n=27, but the diploid gamete comes from taxa possessing 2n=22 instead of 2n=16.     

A Study on the Genus Rubus of China

The genus Rubus is one of the largest genera in the Rosaceae, consisting of more than 750 species in many parts of the world, of which 194 species have been recorded in China. In the present paper the Rubus is understood in its broad sense, including all the blackberries, dewberries and raspberries, comprising the woody and herbaceous kinds. So it is botanically a polymorphic, variable and very complicated group of plants. The detailed analysis and investigation of the evolutionary trends of the main organs in this genus have indicated the passage from shrubs to herbs in an evolutionary line, although there is no obvious discontinuity of morphological characters in various taxa. From a phylogenetic point of view, the Sect. Idaeobatus Focke is the most primitive group, characterized by its shrub habit armed with sharp prickles, aciculae or setae, stipules attached to the petioles, flowers hermaphrodite and often in terminal or axillary inflorescences, very rarely solitary, druplets separated from receptacles. Whereas the herbaceous Sect. Chamaemorus L. is the most advanced group, which is usually unarmed, rarely with aciculae or setae, stipules free, flowers dieocious, solitary, druplets adhering to the receptacles and with high chromosome numbers (2n = 56). Basing upon the evolutionary tendency of morphological features, chromosome numbers of certain species recorded in literature and the distribution patterns of species, a new systematic arrangement of Chinese Rubus has been suggested by the present authors. Focke in his well-known monograph divided the species of Rubus into 12 subgenera, while in the Flora of China 8 sections of Focke were adapted, but some important revisions have been made in some taxa and Sect. Dalibarda Focke has been reduced to Sect. Cylactis Focke. In addition, the arrangement of sections is presented in a reverse order to those of Focke’s system. The species of Rubus in China are classified into 8 sections with 24 subsections (tab. 3) as follows: 1. Sect. Idaeobatus, emend. Yü et Lu(11 subsect. 83 sp.); 2. Sect. Lampobatus Focke (1 sp.); 3. Sect. Rubus (1 sp.); 4. Sect. Malachobatus Focke, emend. Yü et Lu (13 subsect. 85 sp.); 5. Sect. Dalibardastrus (Focke)Yü et Lu (10 sp.); 6. Sect. Chaemaebatus Focke (5 sp.); 7. Sect. Cylactis Focke, emend. Yü et Lu (8 sp.); 8. Sect. Chamaemorus Focke (1 sp.). In respect to the geographical distribution the genus Rubus occurs throughout the world as shown in tab. 2, particularly abundant in the Northern Hemisphere, while the greatest concentration of species appears in North America and E. Asia. Of the more than 750 species in the world, 470 or more species (64%) distributed in North America. It is clearly showm that the center of distribution lies in North America at present time. There are about 200 species recorded in E. Asia, of which the species in China (194) amount to 97% of the total number. By analysis of the distribution of species in China the great majority of them inhabit the southern parts of the Yangtze River where exist the greatest number of species and endemics, especially in southwestern parts of China, namely Yunnan, Sichuan and Guizhou (tab. 3. 4.). It is interesting to note that the centre of distribution of Rubus in China ranges From northwestern Yunnan to south-western Sichuan (tab. 5), where the genus also reaches its highest morphological diversity. In this region the characteristics of floristic elements of Rubus can be summarized as follows: it is very rich in composition, contaning 6 sections and 94 species, about 66% of the total number of Chinese species; there are also various complex groups, including primitive, intermediate and advanced taxa of phylogenetic importance; the proportion of endemic plants is rather high, reaching 61 species, up to 44% of the total endemics in China. It is noteworthy to note that the most primitive Subsect. Thyrsidaei (Focke) Yü et Lu, consisting of 9 endemic species, distributed in southern slopes of the Mts. Qin Ling and Taihang Shan (Fig. 4). From the above facts we may concluded that the south-western part of China is now not only the center of distribution and differentiation of Rubus in China, but it may also be the center of origin ofthis genus.     

花粉形态计算机量化分析研究

以白莲花粉为实验材料 ,介绍了进行花粉形态计算机量化分析的步骤。花粉经醋酸法处理后 ,用电子显微镜对花粉进行观察照相 ,尔后用计算机技术对花粉电镜照片进行处理 ,最后用C语言编制了计算花粉形态面积的计算机程序。结果表明 :花粉计算机量化分析有助于快速定量测定有关花粉形态指标 ,是花粉数量分类的一种有效方法。     

蛛网菌属在我国的首次报道及其全球地理分布

基于蛛网菌属（ＡｒａｃｈｎｏｃｒｅａＭｏｒａｖｅｃ）的模式标本及其所有种的分类特征的研究进一步明确了其系统分类位置及其分类界定;该属是肉座菌科（Ｈｙｐｏｃｒｅａｃｅａｅ）中一个较原始类型。糙孢蛛网菌（ＡｓｃａｂｒｉｄａＤｏｉ）采于云南西双版纳;并与日本（主模式）和新西兰标本及其近缘种的标本作了微、宏观解剖形态学的比较,确定了本种的变异范围。该属的现代地理分布格局表明它是一个北半球温带分布属,然而其分布向南延伸至热带,历史上很可能它是一个东南亚热带起源的属,这一地域极可能是该属的物种分化中心     

The Genus Nomocharis

Background: Ziziphus lotus, wild jujube, is a xerophytic shrub of the Rhamnaceae family widely distributed in arid and semi-arid regions of Tunisia, where it occupies most soil types. Phenological patterns of desert plants are strongly affected by the seasonality of water availability and phreatophytes represent a particularly interesting case for studying such relationships.

Aim: This study aims to investigate the relationship between phenological traits and water potential patterns of the wild jujube as a tool for understanding how plants cope with extreme drought.

Methods: Phenophases and predawn (Ψ_pd) and midday (Ψ_md) xylem water potentials of wild jujube were studied monthly (Nov 2007–Oct 2008) at Samaâliate and Oued El Hallouf in southern Tunisia. These sites receive164 mm and 191 mm of annual rainfall, respectively, and differ in slope and soil type.

Results: The Ψ_md decreased progressively and concomitantly with increasing seasonal drought, reaching the lowest values in late summer (down to –3.9 MPa for both sites). Seasonality of Ψ_pd was less pronounced for plants established in Oued El Hallouf (–2.09 MPa) than in Samaâliate (–2.63 MPa) at the end of the dry season. Wild jujube is dormant from October through to March and mature plants flower in May and produce fruits in August.

Conclusions: Our results clearly demonstrate that wild jujube is a drought tolerant species reaching low water potentials during the driest months of summer.