新疆2种盐生补血草营养器官的解剖学研究

采用叶片离析法和石蜡切片法,对生长在新疆盐渍环境中的大叶补血草[Limonium gmelinii(Willd.) Kuntze]和耳叶补血草[Limoniumotolepis(Schrenk) Kuntze]的营养器官解剖学特征进行了观察研究.结果显示,2种补血草属典型泌盐植物,茎和叶片表皮上分布有多细胞组成的盐腺;叶表皮细胞排列紧密,其外切向壁增厚,表皮外还被有厚的角质层;上下表皮都有气孔,气孔与表皮细胞平齐,为不等型气孔;其中大叶补血草为异面叶,而耳叶补血草为等面叶.2种补血草茎中都散生有多轮维管束;大叶补血草根中还有大量通气组织等.研究结果表明,2种补血草的解剖结构表现出与其生境相适应的特征.     

假俭草和结缕草营养器官结构对抗逆性的影响

利用光学显微镜和电镜技术,采用石蜡切片法,叶片离析法等实验技术对假俭草和结缕草的茎,叶等营养器官的解剖结构特征和表皮微形态特征作了研究;通过角质层厚度,维管束数目,气孔指数,泡状细胞等数据分析它们之间的抗逆性差别;首次从微形态角度初步了解假俭草和结缕草及其不同种群之间抗旱力,耐践踏性差异的原因。     

新疆四种补血草属植物叶片的解剖学研究

利用叶片离析法和石蜡切片法研究了补血草属4种植物叶片的形态结构。结果表明:(1)4种植物的叶片有许多共同的结构适应特征,表皮细胞排列紧密,表面有厚的角质层;气孔类型均为不等型,气孔位置为平置或略微下陷;上下表皮还具有多细胞构成的盐腺;栅栏组织发达,多为等面叶;存在粘液细胞和单宁细胞;机械组织和维管组织都不发达等。(2)不同种间有不同的结构适应特征,如表皮细胞的形状、大小、垂周壁饰样,气孔密度,盐腺密度,叶片厚度和栅栏组织厚度等。通过叶的结构特征反映出盐生植物与旱生植物的不同。     

星星草营养器官适应盐胁迫的结构特征

采用0．6％Na2CO3胁迫处理星星草[Puccinellia tenuiflora（Turcz．）Scribn．et Merr．]幼苗,光镜和电镜观察其根和叶的显微和超微结构。结果表明,星星草根的表皮向外突出形成密集的根毛;外皮层由1～2层细胞组成,排列较紧密;中皮层薄壁细胞排列疏松,形成发达的通气组织;内皮层呈典型的五面加厚;中柱鞘排列紧密,其壁加厚;初生木质部与初生韧皮部相间排列,初生木质部为5～7原型,中央为后生木质部导管,无髓存在。叶的表皮有表皮毛和丰富的蜡质层;叶上表皮泡状细胞数目较少,且深陷;气孔下陷,其下有较大的气室;叶脉有大、中、小3种维管束,大、中型维管束为C3型,小型维管束为C4型。星星草可能是介于C3和C4植物之间的类型,具有耐盐碱及耐干旱特征。     

中华补血草盐腺发育的解剖学研究

采用叶表皮印痕、扫描电镜以及石蜡切片法对中华补血草的叶片进行解剖研究,观察其成熟盐腺的结构、盐腺的发育与盐腺的密度。结果表明:(1)上表皮的盐腺密度比下表皮的略小。(2)成熟的盐腺由20个细胞构成,中央有4个分泌细胞,每一个分泌细胞外侧又伴有一个长方形的毗邻细胞;向外由2层杯状细胞包围,每一层分别有4个杯状细胞,使盐腺呈近似圆形;盐腺内部靠近叶肉细胞处有4个收集细胞;中央4个分泌细胞顶端的角质层各有一小孔,是盐分泌出的通道。(3)中华补血草盐腺是由一个单独的表皮细胞发育而成,分别经历单细胞时期、2细胞时期、4细胞时期、8细胞时期、16细胞时期和20细胞时期的不同发育阶段。     

大米草(Spartina anglica Hubbard)盐腺的形态结构

大米草的盐腺在植物体的分布,除根、根茎、茎、叶鞘的近轴面以及内稃没有外,其他所有气生部分皆具有,尤其以叶片最多。盐腺由两个细胞组成,大的基细胞和小的圆顶状的帽细胞。帽细胞位于基细胞颈状突起上面。两者都具有浓稠的细胞质、大的细胞核多数线粒体以及少数其他细胞器。基细胞具有遍布整个细胞的壁突起和折叠的隔膜系统,将细胞质分隔。帽细胞的显著特征是核仁明显,染色质遍及整个核质并沿核膜分布。基细胞肩部和底部与表皮细胞和叶肉细胞之间没有角质层隔开,而基细胞与表皮细胞和帽细胞邻接的壁上有明显的胞间联丝。大米草盐腺的发育可能与唐氏米草(S.townsendii)相同;其泌盐途径可能是叶米草(S.foliosa)与唐氏米草两者兼有之。     

盐生植物星星草叶表皮具有泌盐功能的蜡质层

利用扫描电镜和 X射线电子探针研究了星星草 (Puccinellia tenuiflora)的叶表皮及其与生境高盐的关系。结果表明 ,叶表皮由表皮细胞和气孔器组成 ,下表皮气孔器多于上表皮 ,且常下陷 ,表皮具表皮毛。表皮细胞外存在丰富的蜡质纹饰和蜡质颗粒 ,这些蜡质包含盐离子 ,具有泌盐的功能。这些特征表明星星草受外界生态因素的影响 ,而演化出具有泌盐功能的蜡质层来适应所生长的高盐生境     

四种补血草属植物叶片泌盐结构的扫描电镜观察

利用扫描电镜技术,对4种补血草属植物大叶补血草（Limonium gmelinii (Willd.) Kuntze）、耳叶补血草（Limoniu otolepis (Schrenk) Kuntze）、繁枝补血草（Limonium myrianthum (Schrenk) Kuntze）和簇枝补血草（Limonium auream）的叶表面进行了研究,以探讨植物微形态结构与生态环境的关系。结果表明,这4种植物的上下表皮都分布有盐腺,且上表皮的盐腺密度大于下表皮,盐腺的基本结构相同,多由20个细胞构成,其中4个分泌细胞顶端的角质层中央有一小孔,植物体靠盐腺的泌盐孔泌盐。但4种植物在盐腺的密度、盐腺的大小、盐腺与周围表皮细胞的位置等方面存在差异。植物在对盐碱生境的长期适应过程中,促使其强烈地分化出泌盐结构,因而,具有明显的生态适应性。     

偏序钝叶草（Stenotaphrum secundatum）与地毯草（Axonopuscompressus）营养器官特点的研究

偏序钝叶草（Ｓｔｅｎｏｔａｐｈｒｕｍｓｅｃｕｎｄａｔｕｍ（Ｗａｌｔ．）Ｋｕｎｔｚｅ）与地毯草（Ａｘｏｎｏｐｕｓｃｏｍｐｒｅｓｓｕｓ（Ｓｗａｒｔｚ）Ｂｅａｕｖ．）均为热带和亚热带的草坪优良草种,它们的匍匐枝节节可生根和产生分蘖,覆盖面积大。偏序钝叶草根毛分布范围较广,寿命较长;地毯草植株平铺地面,它们都是良好的保土植物。偏序钝叶草茎和叶的维管束都较密集,厚壁组织较发达,植株有一定的韧度。它们的叶的维管束解剖呈现“花环”结构,属Ｃ４植物。     

烟台补血草盐腺结构及发育过程观察

利用叶表皮离析、扫描电镜以及常规石蜡切片法对烟台补血草[ Limonium franchetii( Debx.) Kuntze]叶片盐腺的分布和结构特征及其发育过程进行了观察.结果表明:烟台补血草叶片上、下表皮均有盐腺分布,上、下表皮的盐腺密度分别为7.57和8.09 mm-2,同一时期叶片上表皮盐腺密度略小于下表皮.烟台补血草的成熟盐腺是由20个细胞构成的复合结构,其中,中央有4个分泌细胞,每个分泌细胞外侧均伴有1个长方形的毗邻细胞,再向外依次包围着4个内杯状细胞和4个外杯状细胞,靠近叶肉细胞处还有4个收集细胞,收集细胞与盐腺的其他细胞同源;在4个分泌细胞顶端的角质层中央各有1个小孔,称为泌盐孔.烟台补血草盐腺发育过程依次经历原表皮细胞期、2细胞期、4细胞期、8细胞期、16细胞期和20细胞期6个阶段,由1个单独的原表皮细胞发育而成,发育过程中细胞均进行垂周分裂;另外,同一时期的叶片存在盐腺发育不同步的现象.根据观察结果推测烟台补血草主要通过泌盐孔L向外泌盐.     

Comparative vegetative anatomy and systematics of Vanilla (Orchidaceae)

Vanilla is a pantropical genus of green-stemmed vines bearing clasping (aerial) and absorbing (terrestrial) roots. Most vanillas bear normal, thick foliage leaves; others produce fugacious bracts. Seventeen species, including both types were studied. Foliage leaves of Vanilla are glabrous, have abaxial, tetracytic stomatal apparatuses, and a homogeneous mesophyll. Species may or may not have a uniseriate hypodermis. Crystals occur in the foliar epidermises of some species, but all species have crystalliferous idioblasts with raphides in the mesophyll. Vascular bundles in leaves are collateral and occur in a single series alternating large and small. Sclerenchyma may or may not be associated with the vascular bundles. Scale leaves may be crescent or C-shaped and usually have abaxial stomatal apparatuses. A hypodermis may or may not be present; the mesophyll contains raphide bundles in idioblasts. Vascular bundles are collateral and occur in a single row sometimes aligned close to the adaxial surface. They may or may not be associated with sclerenchyma. Stems of leafy vanillas show a sclerenchyma band separating cortex from ground tissue; stems of leafless vanillas do not show a sclerenchyma band. Ground tissue of the stem may consist solely of assimilatory cells or mixed assimilatory and water-storage cells. In some species centrally located assimilatory cells are surrounded by layers of water-storage cells. A uniseriate hypodermis is present in all stems. Sclerenchyma may completely surround the scattered collateral vascular bundles, occur only on the phloem side, or be absent. Both aerial and terrestrial roots are notable for their uniseriate velamen the cell walls of which may be unmarked or ornamented with anticlinal strips. Exodermis is uniseriate; the cells vary from barely thickened to strongly thickened. Only the outer and radial walls are thickened. Cortical cells of aerial roots generally have chloroplasts that are lacking from the same tissue of terrestrial roots. Raphide bundles occur in thin-walled cortical idioblasts. Endodermis and pericycle are uniseriate; pericycle cells are all ?-thickened opposite the phloem. Cells of the endodermis are either ?- or ∪-thickened opposite the phloem. Vascular tissue may be embedded in thin- or thick-walled sclerenchyma or in parenchyma. Metaxylem cells are always wider in terrestrial than in aerial roots of the same species. Pith cells are generally parenchymatous but sclerotic in a few species.     

Comparative vegetative anatomy of Stanhopeinae (Orchidaceae)

Stanhopeinae are a group of tropical American orchids characterized by euglossine bee pollination and lateral inflorescences stemming from the bases of pseudobulbs. Leaves are hypostomatal, and all stomatal configurations are tetracytic. Chlorenchyma is homogeneous and characterized by fibre bundles in adaxial/abaxial or adaxial/median/abaxial positions. Collateral vascular bundles occur in a single row and feature phloic and xylic sclerenchymatous caps and thin-walled bundle sheath cells. Fibre bundles and vascular sclerenchyma are accompanied by stegmata containing conical silica bodies. Pseudobulbs have thick-walled turbinate epidermal cells and ground tissue of smaller, living assimilatory cells and larger, dead water-storage cells. Fibre bundles are usually absent but occur in several genera. Collateral vascular bundles show phloic sclerenchyma, but xylic sclerenchyma occurs only in die larger vascular bundles. Phloic and xylic sclerenchyma are associated with stegmata containing conical silica bodies. Roots are velamentous. Velamen cell walls have fine, spiral thickenings. Exodermal cells are thin-walled. The cortex features scattered thick-walled cells and in some cases branched bars of secondary cell wall material. Endodermis is either u-or O-thickened, but pericycle is always O-thickened opposite the phloem. Vascular tissue consists of alternating strands of xylem and phloem surrounded by a matrix of thick-walled cells. Pith cells may be parenchymatous or sclerenchymatous.     

Comparative anatomy and systematics of Catasetinae (Orchidaceae)

Catasetinae consist of five genera of pseudobulbous Orchidaceae of the Neotropics. Anatomy is characterized by sunken, three-celled foliar hairs, mostly tetracytic stomatal apparatuses, superficial stomata, homogeneous mesophyll, foliar fibre bundles, collateral vascular bundles in a single row, xylem and phloem sclerenchyma associated with vascular bundles in leaves, conical, and rough-surfaced silica bodies adjacent to vascular bundle sclerenchyma; epidermal cells of pseudobulbs with heavily thickened outer walls, pseudobulb ground tissue of assimilatory and water-storage cells, scattered vascular bundles in pseudobulbs, and sclerenchyma and stegmata associated only with phloem of pseudobulbs; roots with thin-walled velamen cells and tenuous spirals of cell wall material, distinctive epivelamen cells, thin-walled exodermal cells and vascular tissue embedded in parenchyma. Except for mucilaginous idioblasts that occur in Mormodes and Cycnoches , there are few outstanding anatomical differences among the five genera. Thus, there are few anatomical characteristics of phylogenetic value. The monophyly of Catasetinae is supported by the presence of sunken foliar hairs. Our results support a close relationship between Clowesia and Catasetum , and between Mormodes and Cycnoches. Among the outgroups Pteroglossaspis is especially distinctive.     

Evolution in Spartina (Gramineae): III. Species chromosome numbers and their taxonomic significance

The chromosome numbers of nine species of the genus Spartina have been determined and their meiotio pairing has been examined. All numbers are referable to either 2 n = 40 ( S. pectinata, S. patens, S. cynosuroides, S. gracilis, S. bakeri and S. arundinacea ), 2 n =60 ( S. maritima ) or 2 n =62 ( S. alternifiora and 8. glabra ). No intraspeoifio polyploids have been found. Supernumerary or B -chromosomes occur rarely in S. pectinata . Hence the basio chromosome number is deduced as being x = 10 for these speoies in contrast to former reports of x = 7. The implications of the new basic number with respect to taxonomic position are pointed out.     

Nutrients, competition and plant zonation in a New England salt marsh

1 We examined the effects of nutrient availability on the competitive interactions of the New England salt marsh perennials that occupy discrete vegetational zones parallel to the shoreline.
2 Fertilized and unfertilized plots of pair-wise mixtures and monocultures of Spartina alterniflora, S. patens and Juncus gerardi were compared in order to assess the effects of nutrient addition on the competitive dynamics of these species in the field. In addition, we examined competition between some of these species and Distichlis spicata , a species common to disturbed marsh habitats.
3 After two growing seasons, changes in above-ground biomass of the species indicated that in fertilized plots, S. alterniflora outcompeted S. patens, S. patens outcompeted J. gerardi, and D. spicata outcompeted both J. gerardi and S. patens. This was the reverse of the interactions seen under ambient marsh conditions, and suggested that, under conditions of nutrient limitation, competitive dominance may result from efficient competition for nutrients.
4 Using a conceptual model of salt marsh zonation as a function of competition, physical stress and nutrient limitation, we hypothesize that a nutrient-induced reversal in the competitive dynamics among salt marsh perennials may result in modification of the pattern of plant zonation in this and similar marshes.     

刺槐叶的亚显微结构与耐旱性的关系

刺槐（RobiniapseudoacaciaLinn．）虽然引自北美,但现在已成为西北干旱半干旱地区的主要造林树种。叶片形状为羽状复叶,小叶呈椭圆形,叶面积与体积之比为5．6。叶表面具蜡质壳状、管状毛和鳞片状纹饰。叶片与叶柄被以毛状体;叶背面有浅内陷气孔,具大孔下室。上下表皮细胞外壁具明显的角质层加厚;上表皮细胞呈椭圆形,下表皮细胞呈乳头状;栅栏组织与海绵组织之间界限不明显,栅栏组织较为发达,排列紧密,约2—3层细胞,海绵组织有退化的趋势;中脉和叶柄维管束均有厚壁组织细胞组成的维管束鞘;薄壁组织细胞中含有大量的晶体和淀粉粒,叶片已具有许多旱生特征。     

海桑和无瓣海桑叶片结构的比较研究

为了探讨外来植物无瓣海桑的潜在危害,采用石蜡切片法对海桑(Sonneratia caseolaris Engl.)、无瓣海桑(S.apetala B.Ham)叶片进行了解剖学研究。实验结果显示,两种植物的叶片均为等面叶;中脉维管束为周韧维管束;具4级侧脉,第1级侧脉为半周韧维管束;成熟叶片叶肉组织具发达的贮水薄壁细胞,具含单宁成分的薄壁细胞,具晶体细胞和石细胞;盐腺由表皮细胞发育而成,可分为3个发育阶段。作为外来植物的无瓣海桑,其中脉维管束具微弱形成层,叶脉维管组织比海桑更发达;贮藏组织中含单宁细胞、晶体细胞较多;栅栏组织含叶绿体多于海桑等特点,使其比海桑对环境具有更大的适应性。因此,无瓣海桑有可能成为入侵植物。     

葡萄属营养器官的比较解剖学及其系统学意义

本文对国产葡萄属24个种、6个变种和4个美洲种进行了比较解剖学研究。比较观察了茎、节、 叶柄、叶片的维管系统、厚角组织、厚壁组织、毛状体、后含物、叶表皮角质等解剖学特征。并讨论了它们在系统学上的意义。     

The evolution of Spartina anglica G. E. Hubbard (Gramineae): genetic variation and status of the parental species in Britain

The perennial salt marsh grass Spartina anglica is one of the classic examples of allopolyploid speciation. It originated on the south coast of England at the end of the nineteenth century following chromosome doubling in S. × townsmdii , a hybrid between the native British S. marilima and a species introduced from the United States, S. alterniflora. The nature of the origin of S. anglica is beyond doubt; however, it is not known whether it had a single or multiple origin. In order to address this problem we undertook a survey of the genetic variation in the parental species of S. anglica using isozyme electrophoresis. The results show that S. alterniflora has no detectable variation and that S. maritima has extremely low levels of variation. These results, unfortunately, prevent the question of a single or multiple origin from being answered. Possible reasons for the low levels of variation and its influence on the future of the species are discussed. Another problem concerning the parental species is the rapid decline of S. maritima in Britain. It is often assumed that the major factor in this regression is the invasion of its habitats by S. anglica. We have examined the status of S. marilima throughout its range in Britain and have found that S. anglica rarely co-occurs with S. maritima. We propose that the decline of S. maritima is largely due to the physical erosion of its habitats and that this erosion may produce suitable habitats for colonization by S. anglica.     

Vegetative anatomy of subtribe Habenariinae (Orchidaceae)

Leaves of Habenariinae are characterized by anomocytic stomatal apparatuses, homogeneous mesophyll, collateral vascular bundles in a single series, and thin-walled bundle sheath cells. There is no foliar sclerenchyma nor a hypodermis. Cauline cortex consists of thin-walled living cells among which are large and numerous intercellular spaces. The ground tissue is bordered externally by a layer of thick-walled living cells, except in Habenaria repens. Central ground tissue cells are living, and usually thin-walled surrounding intercellular spaces of various dimensions. These are conspicuously large in H. repens. Collateral vascular bundles are scattered across the ground tissue. Sclerenchyma is absent. Absorbing roots are generally velamentous, exodermal dead cells are diin-walled, and passage cells usually have a thickened outer wall. A regular vascular cylinder is present, and vascular tissue is embedded in parenchyma. Root tubers are velamentous, exodermal cells are usually thin-walled, and passage cells frequently have thickened outer walls. Vascular tissue of root tubers is organized into two classes: (1) those with a single vascular cylinder surrounded by a cortex and (2) those with a series of meristeles dispersed throughout the ground tissue. In group (1) cortex is homogeneous either with or without mucilage cells except in Stenoglattis where the cortex is heterogeneous, consisting of water-storage and assimilatory cells, and lacks mucilage cells. In group (2) the ground tissue consists of larger mucilage-containing cells and smaller assimilatory cells.