The genus Eugenia L. (Myrtaceae) in southern Africa: the structure and taxonomic value of stomata

The mature stomatal morphology of 11 southern African species of Eugenia , and also of E. uniflora L. (naturalized) and E. incerta Diimmer (a garden plant of unknown origin) has been studied by light and scanning electron microscopy.
Leaves of all the species are hypostomatic and water-stomata are occasionally present. Two different stomatal types, X and Y, differing mainly in their cuticular ornamentation, were found in the southern African species. The grouping of species based on stomatal characters supports a previous grouping of species on the basis of periderm and seed characters.
Conspicuous lipid bodies, usually present in the subsidiary cells, are limited to the southern African species. Although the subsidiary cells do not differ in shape and size from adjacent epidermal cells, their contents often have a higher tannin content than ordinary epidermal cells. The variable patterns of arrangement of the three to five subsidiary cells makes it difficult to identify the stomata with existing classifications based on mature topography. Thus, a new term 'anomostaurocytic' is proposed for the stomatal type found in the southern African species.
Stomata of E. uniflora and E. incerta are paracytic and anomocytic respectively, and the cuticular ornamentation of their stomata differs from those of the southern African species. The view that E. incerta is not closely related to the southern African species is supported by differences in its cuticular ornamentation, lack of lipid bodies in the subsidiary cells, anomocytic stomata and prominent T-pieces at the guard cell poles.     

Leaf anatomical studies of Eugenia L. (Myrtaceae) species from the Malay Peninsula

KHATIJAH, H. H., CUTLER, D. F. & MOORE, D. M., 1992. Leaf anatomical studies of Eugenia L. species from the Malay Peninsula. The leaf and petiole anatomy of 25 Malaysian species of Eugenia L. sensu lato was investigated to determine the value of vegetative anatomy for the identification of non-flowering material. Twelve characters proved useful for the identification of species: type of stomata; shape of leaves in T.S.; shape of midrib bundle; sclerenchyma sheath; cutinization of outer epidermal wall; presence or absence of sclereids, idioblasts, hypodermis, columnar epidermal cells, solitary crystals; number of palisade layers and the shape of vascular strand, sclerenchyma sheath and sclereids in the parenchyma of the petiole. Using these characters an anatomical key was constructed to assist identification of the species. Only the closely related species E. stapfiana and E. nilidula could not be separated on anatomical characters.
The anatomical data support the treatment of Henderson (1949) of section Acmena but not of sections Cleistocalyx and Fissicalyx , which fit better in section Syzygium.     

哈萨克斯坦中部(Kaydagul Formation) 欧洲水松的角质层结构分析

研究了哈萨克斯坦中部上渐新统/下中新统的欧洲水松(Glyptostrobus europaeus (Brongn.) Ung.)的枝叶微形态结构,并利用扫描电子显微镜和光学显微镜与"现存最近亲缘种"--水松(G. pensilis C. Koch)的表皮特征进行了比较.     

哈萨克斯坦中部（Kaydagul Formation）欧洲水松的角质层结构分析

研究了哈萨克斯坦中部上渐新统／下中新统的欧洲水松(Glyptostrobus europaeus(Brongn.)Ung．)的枝叶微彤态结构,并利用扫描电子显微镜和光学显微镜与“现存最近亲缘种”——水松(G.pensilis c.Koch)的表皮特征进行了比较。     

Complete Nucleotide Sequence of the Chloroplast Genome from the Tasmanian Blue Gum, Eucalyptus globulus (Myrtaceae)

The complete nucleotide sequence of the chloroplast genome ofthe hardwood species Eucalyptus globulus is presented and comparedwith chloroplast genomes of tree and non-tree angiosperms andtwo softwood tree species. The 160 286 bp genome is similarin gene order to that of Nicotiana, with an inverted repeat(IR) (26 393 bp) separated by a large single copy (LSC) regionof 89 012 bp and a small single copy region of 18 488 bp. Thereare 128 genes (112 individual gene species and 16 genes duplicatedin the inverted repeat) coding for 30 transfer RNAs, 4 ribosomalRNAs and 78 proteins. One pseudogene (-infA) and one pseudo-ycf(-ycf15) were identified. The chloroplast genome of E. globulusis essentially co-linear with that of another hardwood treespecies, Populus trichocarpa, except that the latter lacks rps16and rpl32, and the IR has expanded in Populus to include rps19(part of the LSC in E. globulus). Since the chloroplast genomeof E. globulus is not significantly different from other treeand non-tree angiosperm taxa, a comparison of hardwood and softwoodchloroplasts becomes, in essence, a comparison of angiospermand gymnosperm chloroplasts. When compared with E. globulus,Pinus chloroplasts have a very small IR, two extra tRNAs andfour additional photosynthetic genes, lack any functional ndhgenes and have a significantly different genome arrangement.There does not appear to be any correlation between plant habitand chloroplast genome composition and arrangement.     

Two new species of Eugenia (Myrtaceae) from Central French Guiana

Eugenia argyrophylla andE. morii from Saül in Central French Guiana are described and illustrated.     

Observations on the structure of epidermal cells, particularly the cork and silica cells, from the flowering stem internode of Lolium temulentum L. (Gramineae)

Features of the epidermis such as stomata, hairs, cork and silica cells are described from both light and electron microscope studies. The stomatal complex consists of two guard cells and two subsidiary cells. After division of the guard mother cell a pore is left at each end of the dividing wall. The cork and silica cells arise from a single another cell and develop differentially. The silica cell enlarges more than the cork cell and finally becomes filled with solidified silica. The outer tangential and radial walls of the cork cells become very thick-walled, whereas the inner tangential and radial walls of the silica cells become thickened. The outer tangential wall of the silica cell remains thin and is covered with a thin layer- of cuticle. This wall frequently collapses in old cells leaving a depression in the surface of the stem. The change in the ultrastructure of the cork and silica cells are described and the possible functions of these cells discussed.     

Reproductive biology, variability of nectar features and pollination of Combretum fruticosum (Combretaceae) in Argentina

Flower morphology, nectary structure, nectar features (chemical composition, secretion pattern, standing crop, removal effects) and flower visitors are analysed in an Argentinian population of Combretum fruticosum. The variability of these data was examined throughout the flower lifetime. Nectar is hexose dominant. Its chemical composition and concentration are constant for all flowering stageS. Nectar volume varies as a function of flower age due to a combination of nectar secretion, cessation and resorption periods. The overall sugar production is decreased by nectar removal. The plant is self-incompatible and xenogamouS. Only 16.2% of the flowers set seedS. Inflorescences with green flowers were exclusively visited by two hummingbird and three perching bird species which transfer the pollen. A clear link was observed among nectar production pattern, standing crop of nectar, and visitors' behaviour.     

Population genetics of Glutathione peroxidase (GPX1) in Central Portugal

The isoenzymes of red cell glutathione peroxidase (GPX1) was investigated in the population of Central Portugal. A variant of GPX1 with mobility consistent with GPX1^*2 was detected with a frequency of: GPX1^*2=0,005 (N=221).     

Morphological characteristics of leaf epidermis and size variation of leaf, flower and fruit in different ploidy levels in Buddleja macrostachya (Buddlejaceae)

Buddleja macrostachya (Buddlejaceae) is a widespread shrub native to the Sino-Himalayan mountains and beyond. It has been found to occur at two ploidy levels, hexaploid, 2n=6x=114 and dodecaploid, 2n=12x=228. To determine if morphological characters might be used as indicators of ploidy levels, we measured floral and fruit length, relative and absolute leaf size, trichome density on both leaf surfaces, and stomatal density and length in different populations of B. macrostachya. In general, flower and fruit length, absolute leaf size, and stomatal length increased with an increase at ploidy level (P<0.01), whereas adaxial cell and stomatal density decreased with an increase at ploidy level (P<0.01). We found no conspicuous differences in relative leaf size (P>0.05) in different populations. Other characters studied such as trichome type, cuticular membrane and ornamentation of stomata, cell and stomatal shape, and anticlinal wall pattern were quite constant in this species. Thus it appears that flower and fruit length, absolute leaf size, and stomatal frequency and length can be used to distinguish hexaploid from dodecaploid cytotypes either in the field or in herbarium specimens.     

Anatomy of the extrafloral nectaries in species of Chamaecrista section Absus subsection Baseophyllum (Leguminosae,Caesalpinioideae)

In this paper the ontogenesis and histochemistry of the petiolar glands found on the petiole/rachis of the eight Chamaecrista species of the section Absus, subsection Baseophyllum (Leguminosae, Caesalpinioideae) are studied by using light microscopy techniques, aiming to characterise these structures and to provide taxonomic characters which may be useful in phylogenetic approaches. Strips for glucose identification reacted positively with the exudates of the glands, confirming the presence of nectar in the secretion, characterising these glands as extrafloral nectaries (EFN). Histochemical tests also detected the presence of neutral and acid muco-polysaccharides, pectins, mucilages, total proteins, and phenolic compounds in the EFNs. The EFNs arise from a group of meristem cells (protodermis, ground meristem and procambium) in the petiole/rachis. All EFNs of the investigated taxa share some morpho-anatomical characters, so that their peculiarities are too weak to be used alone in the identification of particular species. Rather their similarities may be used to include these species into a single group, supporting the hypothesis of monophyly of the subsection Baseophyllum.     

Genetic and palaeo-climatic evidence for widespread persistence of the coastal tree species Eucalyptus gomphocephala (Myrtaceae) during the Last Glacial Maximum

Background and Aims

Few phylogeographic studies have been undertaken of species confined to narrow, linear coastal systems where past sea level and geomorphological changes may have had a profound effect on species population sizes and distributions. In this study, a phylogeographic analysis was conducted of Eucalyptus gomphocephala (tuart), a tree species restricted to a 400 × 10 km band of coastal sand-plain in south west Australia. Here, there is little known about the response of coastal vegetation to glacial/interglacial climate change, and a test was made as to whether this species was likely to have persisted widely through the Last Glacial Maximum (LGM), or conforms to a post-LGM dispersal model of recovery from few refugia.

Methods

The genetic structure over the entire range of tuart was assessed using seven nuclear (21 populations; n = 595) and four chloroplast (24 populations; n = 238) microsatellite markers designed for eucalypt species. Correlative palaeodistribution modelling was also conducted based on five climatic variables, within two LGM models.

Key Results

The chloroplast markers generated six haplotypes, which were strongly geographically structured (G_ST = 0·86 and R_ST = 0·75). Nuclear microsatellite diversity was high (overall mean H_E 0·75) and uniformly distributed (F_ST = 0·05), with a strong pattern of isolation by distance (r² = 0·362, P = 0·001). Distribution models of E. gomphocephala during the LGM showed a wide distribution that extended at least 30 km westward from the current distribution to the palaeo-coastline.

Conclusions

The chloroplast and nuclear data suggest wide persistence of E. gomphocephala during the LGM. Palaeodistribution modelling supports the conclusions drawn from genetic data and indicates a widespread westward shift of E. gomphocephala onto the exposed continental shelf during the LGM. This study highlights the importance of the inclusion of complementary, non-genetic data (information on geomorphology and palaeoclimate) to interpret phylogeographic patterns.     

Structure and histochemistry of the extrafloral nectary ofAcacia terminalis (Salisb.) MacBride (Leguminosae,Mimosoideae)

Summary The extrafloral nectary ofAcacia terminalis is of the flat type and is located on the adaxial surface of the petiole of the bipinnate leaf. The secretory area is restricted to the base of the trough and no gaps or pores were detected by staining with vital dyes. Between the vascular bundles beneath the nectary and the surface cuticle there were three cell types. The cells of the flanking zone adjacent to the vascular bundles did not appear to be producing secretion whereas the cells of the glandular and secretory zones were secreting. The cells of the glandular zone were elongated whereas those of the surface secretory zone were spherical. Both had endoplasmic reticulum and Golgi bodies with secretory vesicles which were observed in close association with the plasmalemma. Secretion accumulated in the intercellular spaces of the glandular zone cells and forced the cells of the secretory zone apart. Symplastic contact was maintained in all cell types by plasmodesmata which were often associated with endoplasmic reticulum. Secretion accumulated beneath the cuticle which was distended but remained intact on the surface of the secretion.     

Morpho-anatomical features of the leaves of the mediterranean geophyteUrginea maritima (L) baker (Liliaceae)

The morpho-anatomy and histochemistry of the hysteranthous leaf ofUrginea maritima (L.) Baker and its adaptive strategies to the Mediterranean climate were investigated. The leaf ofU. maritima is 714 μm thick and possesses moderate specific leaf mass (8.564 mg cm^-2) and low tissue density (136.5 mg cm^-3). The epidermal cells are compactly arranged and covered with cuticle. The average density of stomata in lower epidermis is higher than that of the upper one. The mesophyll cells occupy 52.96% of the total volume of the leaf, while the mesophyll intercellular spaces and the air spaces occupy 30.41%. Idioblastic cells containing raphide bundles and different phenotypes of crystalloid inclusions, embedded in polysaccharides, occur in the lower side of the mesophyll. The presence of oil droplets and lipids is evident. Bundle sheath cells are hardly visible with no chloroplasts which are a pronounced C₃ plant character. Plastids containing protein crystalloid inclusions are abundant in the protophloem sieve elements.U. maritima, a deciduous plant, possesses leaves with mesophytic characters, in order to optimize its adaptation to the seasonal fluctuation of environmental conditions of the Mediterranean climate.     

Notes on the epidermal features of Degeneria vitiensis I. W. Bailey & A. G. Smith (Degeneriaceae)

The epidermis of leaves of Degeneria vitiensis is described by reference to cuticular morphologies. Paracytic stomata and enlarged stomata are recorded and the detailed structure of the former is described. A variety of other epidermal structures characterized by radially exerted influences upon the general epidermal pavement is also described. On the basis of comparisons with published accounts of the epidermis of other 'ranaleans' the original separation of Degeneria from the Magnoliaceae is supported. Degeneria is considered to have a closer epidermal affinity with some members of the Illiciales than with members of the Magnoliales to which the Degeneriaceae is currently assigned.     

Phylogeny of Australian species of flatheads (Teleostei, Platycephalidae) as determined by allozyme electrophoresis

Phylogenetic relationships of 24 taxa of Platycephalid fish were examined for up to 40 loci using starch and polyacrylarnide gel electrophoresis. Over 400 different enzyme mobilities were scored. The extent of homoplasy was estimated to be between 5 and 12%. Polymorphism at the 1% level was observed at 26 of the 40 loci. The importance of shared polymorphic alleles in cladistic analysis was endorsed by the different results obtained from multistate and binary coding of alleles. Many loci were shown to contain phylogenetically informative ancestral alleles which appear irregularly in extant species. The polymorphism parsimony method provided the most informative results. Genetic similarities between endemic Australian species from each family stem provide the basis for a major revision of subfamilies and genera within the family.     

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.     

Surface features of the adaxial epidermis in the conduplicate-leaved Cypripedioideae (Orchidaceae)

Epidermal cells from adaxial leaf surfaces of 42 species of Paphiopedilum and 6 species of Phragmipedium were surveyed with the SEM. The surfaces of the cells are flat to papillose and often have various sculpturing patterns. To designate two orders of papilla size the terms 'macropapilla' and 'micropapilla' are proposed. Species exhibiting unornamented flat to macropapillose epidermal cells appear to be correlated with high light environments, whereas those species exhibiting micoropapillae and various degrees of sculpturing appear to be correlated with low light environments. Sculpturing features are often characteristic of a single species, but they may vary considerably between species. Epidermal characters are of some utility in identifying sterile plants which are otherwise indistinguishable.