Septal micropores in Zygozyma and their taxonomic significance

Septal micropores or plasmadesmal canals have been observed in two species of the lipomycetaceous genus Zygozyma. The presence of these canals is considered as further evidence for the connexion between the Lipomycetaceae and the Dipodascaceae. The genus Zygozyma has been emended.     

中国凤仙花科植物叶表皮特征及其分类学意义

利用光学显微镜观察凤仙花科106份样本材料、36种代表植物的叶表皮微形态特征。结果表明:该科植物叶表皮微形态特征种内稳定,对于种间及属间关系的界定具有重要的分类学价值。上表皮细胞的形状及垂周壁的式样种间差异明显,各分类群间有明显的界限,是种间界定的重要依据,因此上表皮微形态特征具有重要的的分类学价值,基于上表皮的微形态特征将研究的36种代表植物划分为5个类型。下表皮的微形态特征虽更为多样,种间差异显著,可用于种间界定,但对于属下划分难以提供有价值的性状。该科植物叶表皮微形态特征与宏观形态特征的相关性较弱,与地理分布格局的相关性较强,关系更为密切。同一地理分布区域内的种类宏观形态特征虽然差别明显,但叶表皮微形态特征却表现出较强的一致性,这似乎也反映了叶表皮微形态这一性状受环境饰变的影响比较明显。综上所述,叶表皮微形态特征可为凤仙花科的系统发育,尤其是凤仙花属种间界定提供有价值的分类学佐证     

中国五种仙茅科植物叶形态及其分类学意义

为澄清仙茅科属间界限不清的分类学问题,该文以中国仙茅科3属5种植物为研究对象,利用显微镜、扫描电镜和石蜡切片技术,观察了其叶形态、叶表皮显微特征和叶解剖特征。结果表明:(1)叶形态有小型平整叶、中型波状叶、大型折扇状叶三种。(2)叶表皮毛状体结构为单细胞单列,可分为长柔毛、糙伏毛和星状柔毛三类。(3)叶表皮细胞有六边形和五边形,气孔为平列型和椭圆形,气孔大小和气扎密度呈反比。(4)叶表皮蜡质纹饰有光滑、颗粒、屑状和壳状四类。(5)叶中脉横切面分为平整型和龙骨型,维管束有圆形和椭圆形,叶表皮厚度与表皮细胞具有正相关性。对5种植物的叶形态和叶解剖特征比较分析认为,一些特征组合有助于理解仙茅科属间的亲缘关系和物种鉴定,支持大叶仙茅属独立于仙茅属。     

The ultrastructure of micropropagated and greenhouse rose plant stomata

Stomata of leaves from in vitro grown rose plantlets remain opened in the dark. The ultrastructure of their guard cells was studied after a 7 h light and a 7 h dark period, and compared to that of functional stomata from plants which have been acclimatized to greenhouse conditions. Qualitative and quantitative observations concerning the shape of the guard cells, mitochondria, plastids and starch grains, demonstrated the similarity in guard cell ultrastructure. The peculiarity of guard cell ultrastructure of in vitro cultured plants was the inability to close in the dark; vacuolar area was 40% of the whole guard cell area during both light and dark period whereas, in guard cells from greenhouse plants, the vacuolar area was 40% of the whole guard cell area during the light and only 25% during the dark period. These results indicate that stomata from in vitro plants are duly developed and possess an ultrastructure suitable for a typical functioning. The inability to close in the dark results from atypical water relation.     

Simultaneous and independent effects of abscisic acid on stomata and the photosynthetic apparatus in whole leaves

(±)-Abscisic acid (ABA) at 10^-5 M was added to the transpiration stream of leaves of 16 species (C₃ and C₄, monocotyledons and dicotyledons). Stomatal responses followed one of three patterns: i) stomata that were wide and insensitive to CO₂ initially, closed partially and became sensitive to CO₂; ii) for stomata that were sensitive to CO₂ before the application of ABA, the range of highest sensitivity to CO₂ shifted from high to low intercellular partial pressures of CO₂, for instance in leaves of Zea mays from 170–350 to 70–140 bar; iii) when stomata responded strongly to ABA, their conductance was reduced to a small fraction of the initial conductance, and sensitivity to CO₂ was lost. The photosynthetic apparatus was affected by applications of ABA to various degrees, from no response at all (in agreement with several previous reports on the absence of effects of ABA on photosynthesis) through a temporary decrease of its activity to a lasting reduction. Saturation curves of photosynthesis with respect to the partial pressure of CO₂ in the intercellular spaces indicated that application of ABA could produce three phenomena: i) a reduction of the initial slope of the saturation curve (which indicates a diminished carboxylation efficiency); ii) a reduction of the level of the CO₂-saturated rate of assimilation (which indicates a reduction of the ribulose-1,5-bisphosphate regeneration capacity); and iii) an increase of the CO₂ compensation point. Photosynthesis of isolated mesophyll cells was not affected by ABA treatments. Responses of the stomatal and photosynthetic apparatus were usually synchronous and often proportional to each other, with the result that the partial pressure of CO₂ in the intercellular spaces frequently remained constant in spite of large changes in conductance and assimilation rate. Guard cells and the photosynthetic apparatus were able to recover from effects of ABA applications while the ABA supply continued. Recovery was usually partial, in the case of the photosynthetic apparatus occasionally complete. Abscisic acid did not cause stomatal closure or decreases in the rate of photosynthesis when it was applied during a phase of stomatal opening and induction of photosynthesis that followed a transition from darkness to light.Abbreviations and symbols A rate of CO₂ assimilation - ABA (±)-abscisic acid - c _a partial pressure of CO₂ in the ambient air or in the gas supplied to the leaf chambers - c _i partial pressure of CO₂ in the intercellular spaces of a leaf - e _a partial pressure of H₂O in the air - g conductance for water vapor - J quantum flux - T ₁ leaf temperature     

Structure, distribution and taxonomic importance of stomata in some Indian Tephrosia Pers.(Fabaceae)

SUBBA RAO, J.V.& SHANMUKHA RAO, S. R.(1994).Structure, distribution and taxonomic importance of stomata in some Indian Tephrosia Pers.(Fabaceae).Structure, distribution and taxonomic importance of stomata in all the vegetative parts of 18 taxa of Indian Tephrosia including five species endemic to south India are described. The stomata are anisocytic, anomocytic or paracytic. In addition, brachyparacytic stomata have been recorded for the first time in this taxon. This is the first attempt to assess subgeneric treatment in the light of stomatal characteristics and it suggests certain realignments at the infrageneric level in Indian Tephrosia.     

Survey of leaf anatomy,especially secretory structures,of tribeCaesalpinieae (Leguminosae,Caesalpinioideae)

We studied leaflet anatomy, emphasizing secretory structures, from herbarium specimens of 128 species of 44 genera of tribeCaesalpinieae, using clearings, resin sections, and scanning electron microscopy. These observations, combined with those from our three earlier papers, provide a survey of 210 species representing all genera. Seventy-three species had secretory structures: 21 had glands or gland-like trichomes, 40 had living mesophyll idioblasts, and nine had cavities (three species each had two different types). Five additional species, all inCercidium (Caesalpinia group), had paired or clustered large spheroidal, thick-walled, empty cells (veinlet idioblasts) interconnected by perforation plate-like gaps. Secretory structures have systematic significance at various taxonomic levels.     

Nutlet sculpturing of selectedTeucrium species (Lamiaceae): A character of taxonomic significance

Nutlet sculpturing of 23Teucrium species belonging to six sections was studied. The nutlets of analysed species were characterized by the presence of the oil glands of various density. SectionTeucrium is well defined by very densely distributed trichomes and oil glands on nutlets. Trichomes on nutlets were absent in all other species, except inT. marum from sect.Chamaedrys. Sect.Polium is a homogeneous group, distinguished from the other sections. There are some similarities of this sect. with sect.Scordium. Species of sect.Chamaedrys are heterogeneous and overlap according to the surface sculpturing characters with the other sections. The significance of nutlet microcharacters as additional taxonomical markers in the infrageneric classification of the genusTeucrium is discussed.     

瘤足蕨属(Plagiogyria)植物叶柄和羽片横切面解剖学特征及分类学意义

该文采用光学显微镜,首次对九种瘤足蕨属植物的叶柄和羽片横切面进行了解剖学比较研究。结果表明:九种瘤足蕨属植物在叶柄中部横切面的表皮、基本组织和中柱以及营养叶羽片的表皮、叶肉和主脉等结构特征是相似的,如叶柄中部横切面的表皮不被毛或是鳞片,表皮细胞形状呈类圆形,具有厚壁组织,中柱为周韧型维管束;营养叶羽片横切面的气孔只分布于下表皮,表皮细胞形状呈扁平状,主脉的结构类型属于周韧型维管束。在系统的演化中,瘤足蕨与桫椤科植物有一定的亲缘关系,两者既有相似的特征但也表现出一定的差异,支持瘤足蕨属是一个自然分类的观点。九种瘤足蕨属植物叶柄中部横切面形状有梯形、椭圆形和三角形,叶柄中部横切面维管束的形状成"U"字形、"V"字形或"品"字形;维管束数目1个或3个;维管束结构中的木质部成"八"字形、"U"字形或"一"字形;羽片主脉下侧形成了以三角形、弧形或梯形的突起;叶柄中的木质部形态有两种,即典型的海马形状以及非典型的海马形状,其中典型的海马形状的特点为叶柄的木质部两侧都呈现弯曲成钩的形态,非典型的海马形状特点为2个木质部束的两侧都未出现弯曲成钩的形态或者是其中的一个木质部一端无弯曲成钩的形态,这些形态解剖特征稳定且具类群特异性,为瘤足蕨属植物的分类和系统学研究提供了新的依据。同时,依据其叶柄和羽片横切面解剖叶柄学特征列出了瘤足蕨属植物分种检索表。     

TheUlmaceae, one family or two? Evidence from chloroplast DNA restriction site mapping

The Ulmaceae is usually split into two subgroups, referred to as either tribes or more commonly subfamilies (Ulmoideae andCeltidoideae). The two groups are separated, with some exceptions, on the basis of leaf venation, fruit type, seed morphology, wood anatomy, palynology, chemistry, and chromosome number. Propositions to separate the two groups as distinct families have never gained general acceptance. Recent morphological and anatomical data have suggested, however, that not only is family status warranted but thatCeltidaceae are more closely related toMoraceae and otherUrticales than toUlmaceae. In order to test these alternative sets of relationships, restriction site mapping of the entire cpDNA was done with nine rare cutting enzymes using 11 genera ofUlmaceae s. l., three other families of theUrticales, and an outgroup family from theHamamelidae. Cladistic analysis of the data indicates thatUlmaceae s. l. is not monophyletic and that distinct families (Ulmaceae andCeltidaceae) are warranted; thatUlmaceae is the sister group toCeltidaceae plus all other families in the order; and thatCannabaceae might be nested withinCeltidaceae. Familial placements of various problematic genera (e.g.Ampelocera, Aphananthe) are resolved and character evolution of key morphological, anatomical, chemical, and chromosomal features are discussed.     

山矾科中原氏山矾复合体的叶形态特征及分类意义

该研究在形态学观察以及统计学分析的基础上,深入研究了山矾科中原氏山矾复合体的叶片形态学结构。结果表明:叶片质地在整个复合体中可分为革质、纸质2种类型,叶片大小变异幅度较大,除中原氏山矾(Symplocos kawakamii)、棱角山矾(S.tetragona)、蒙自山矾(S.henryi)均与其他种差异显著外,其余种均属于连续过度,叶片分形可以初步区分该复合体植物。该研究结果为中原氏山矾复合体的进一步研究提供了依据,对复合体的分类处理具有一定的分类学意义。     

The pollen morphology ofOdontites (Scrophulariaceae) and its taxonomic significance

The pollen morphology of 29 species ofOdontites and related genera was examined by light and scanning electron microscopy. Three major pollen types differing fundamentally in exine sculpturing were found. In the parasitic tribePedicularieae retipilate sculpturing is the most widespread type representing a plesiomorphic character state from which the two other types are derived. Of these, reticulate sculpturing is confined toOdontites, whereas a complex retirugulate pattern was found only in the monotypic Near East genusBornmuellerantha. Within the retipilate and the reticulate major types eight minor types were distinguished based on the differential correlation of exine surface morphology, size, shape and amb form. The pollen data are generally well correlated with macromorphological features and furnish important taxonomic characters at the genus—as well as at the specieslevel.     

Amino acids and sugars in nectar,and their putative evolutionary significance

Individual amino acids and sugars from flower nectar of 32 plant species with different pollination systems were quantified and compared. Data show that there is no correlation between sugar and amino acid concentration. Furthermore there is no correlation between composition and concentration of amino acids and evolutionary advancement, nor any direct relation with pollination systems. However, higher sugar concentrations are often linked with more advanced morphological characters. Nectars from pierced or damaged flowers or nectars contaminated with pollen exhibit modifications and increases in amino acid composition. The presence of proline probably indicates such pollen contamination. Most pollinating animals depend on flower nectar in their energetic requirements, yet innumerable alternative amino acid and protein sources exist. Future research has to consider the relationship between nutritional requirements of pollinating animals and dependence on flower nectars.Dedicated to Prof. Dr.L. van der Pijl, Den Haag, in honour of his 80th birthday.     

Morphology, anatomy, and taxonomic position of Pagameopsis (Rubiaceae-Rubioideae)

Morphological and anatomical features (including wood anatomy and pollen morphology) of the small neotropical genusPagameopsis (Rubiaceae-Rubioideae) are discussed and illustrated. The fused ovaries, fenestrate corolla tube, basally attached anther filaments, and absence of raphides are especially noteworthy.Pagameopsis is definitely not a member of the Psychotrieae because of significant differences in wood anatomy and gynoecial and fruit structure. A close affinity with Gaertnereae seems doubtful for similar reasons. The taxonomic affinities ofPagameopsis remain obscure. The genus shows similarities with several taxa of the Rubioideae, such as Coccocypseleae, Morindeae, Hedyotideae, andMetabolos. The absence of raphides, on the other hand, makes a position in the Rubioideae doubtful.     

Climbing of Leaf Trichomes by Eriophyid Mites Impedes Their Location by Predators

Eriophyid mites are plant parasites that are well adapted to hide away from predators. Tiny and wormlike, they can invade very narrow spaces in plants or form galls that, apart from other functions, serve as a shelter from predation. Previous observations showed that some free-living eriophyids as well as tetranychid mites spend their quiescence on the top of leaf trichomes. Here, I investigated climbing leaf trichomes by the eriophyid, Rhinophytoptus concinnus, and tested whether it enables the herbivores to avoid phytoseiid mites. Climbing behavior took place just prior to the quiescent period of juveniles. Larvae and nymphs raised the hind part of their stiffening bodies and walked, turning around on their axis. Having found a hair, juveniles attached their anal suckers to its tip, and, pushing back from a leaf surface or the base of the hair, they lifted their bodies up to become motionless. As revealed by the playback experiments with the phytoseiid mite, Typhloctonus tiliarum, predatory females needed much more time to find quiescent nymphs perching on hairs than those placed on a leaf surface. The time of nymph handling was similar in both situations. Also, a similar number of predators gave up feeding on nymphs in both locations. I conclude that climbing leaf trichomes enables the herbivorous mite to hide from predators. After detection, however, placement on trichomes does not give the quiescent juveniles any advantage over those placed on a leaf blade.     

Phylogenetic analysis ofUlmaceae

A phylogenetic analysis of theUlmaceae, Cannabaceae, Barbeyaceae, andBroussonetia of theMoraceae produced nine equally parsimonious trees with 127 steps. TheUlmoideae (Ulmaceae, sensuGrudzinskaya) are a monophyletic group and distinct from theCeltidoideae. The genusAmpelocera occupies an isolated taxonomic position among the celtidoids. The similarity ofAmpelocera to the fossil celtidoid flowerEoceltis of North America suggests thatAmpelocera posesses an archaic suite of characters, and occupies a primitive position among the celtidoids, theCannabaceae and theMoraceae. The relationships among the other celtidoid taxa,Cannabaceae, andBroussonetia are problematic. TheCannabaceae andBroussonetia of theMoraceae are nested within the celtidoids suggesting that this is a paraphyletic group. The close, but unresolved, relationship of the celtidoids to theMoraceae andCannabaceae observed in this analysis, and the appearance of the celtidoids in the fossil record prior to the ulmoids suggests that the evolutionary relationship of the ulmoids and celtidoids may be more distant than current taxonomic treatments reflect.     

Trichomes: their Diversity,Distribution and Density in Acclimatization of Teak (Tectona grandis L.) Plants Grown in vitro

Diversity, distribution and density of trichomes were studied in relation to other morphological and physiological parameters of in vivo and in vitro teak (Tectona grandis L.) plants with the objective to understand their role in hardening and acclimatization of micropropagated plants. Less diversity and scanty distribution of trichomes of in vitro leaves in comparison to the in vivo ones were correlated with water loss of the former plants leading to low rate of survival after transplantation. The probable cause for absence of certain types of trichome in in vitro plants was also discussed.     

Pollen morphology ofPyrola and its taxonomic significance

Pollen from 152 collections representing 16Pyrola species was examined with LM, SEM and TEM. The genusPyrola is stenopalynous in having tetrads and 3-colporoidate grains. However, a continuous and serial variation in the exine sculpture and the tetrad diameter (D) was revealed within the genus. Křísa's system ofPyrola (1971) was re-examined in the light of these palynological characters which may have a taxonomic significance, as well as the external morphology. P. minor (only member of the subgenusAmelia), which is characterized by having small (D=30–35 μm) pollen tetrads with verrucate sculpture must best be placed near sectionPyrola of the subgenusPyrola. P. faurieana must be segregated from sectionChlorantha and together withP. media placed intermediate between the subgenusAmelia and sectionPyrola of the subgenusPyrola based on their larger (D=ca. 40 μm) pollen tetrads with verrucate sculpture. Two series of sectionChlorantha excludingP. faurieana are differentiated in the exine sculpture. Therefore, they are regarded as the distinct taxonomic groups. SectionScotophylla is characterized by having psilate sculptured pollen tetrads, which indicates that its sectional rank is sufficiently asserted. The evolutionary trend in the exine sculpture from verrucate through rugulate to psilate is suggested withinPyrola.     

Iridoid glucosides substitution patterns inVerbenaceae and their taxonomic implication

The familiar limits ofVerbenaceae are controversial, ranging from a sensu lato arrangement of seven subfamilies until a sharply defined sensu stricto group consisting of only some genera from subfam.Verbenoideae. Iridoid contents of genera belonging toVerbenaceae s. l. were examined through a cladistic analysis, using outgroup analysis to evaluate character polarity within the ingroup. The cladogram obtained shows the distribution of the species according to their iridoid content.     

Ascospore septation inDiploschistes (Thelotremataceae, lichenizedAscomycota) and the taxonomic significance of macro- and microcephalic ascospore types

The ascospore septation in 13 species ofDiploschistes was examined. Microcephalic, macrocephalic, as well as irregular ascospore septation were found. In some species and even specimens of some species, different types of spore septation were detected. The taxonomic significance of the character of ascospore septation sequence is questioned, and the distinction of the ordersGraphidales andOstropales, which was primarily based on this character, is rejected.This paper is dedicated to Prof. DrRolf Santesson (Uppsala) on the occasion of his 80th birthday.