Epidermal Micromorphology Research Articles

Comparative foliar micromorphological studies of some Bauhinia (Leguminosae) species

A comparative foliar epidermal micromorphology of 5 species of Bauhinia L. belonging to family Leguminosae (Fabaceae) was conducted with a view to elucidating their taxonomic significance and presenting complementary data to aid in the identification of the species. The epidermal cells in all species were polygonal with straight walls except in B. tomentosa L., which had an undulating outline. The stoma types were mainly anisocytic, anomocytic, and paracytic. Among the 5 species, B. blakeana L. was hypostomatic with anisocytic and paracytic stomata. Stomatal indices, frequencies, and sizes were determined. The frequency of stomata differed markedly between different species, with the highest frequency in B. malabarica L. and the lowest in B. tomentosa L. Trichomes were either unicellular or multicellular or both. B. malabarica L. can be identified by its unicellular hooked trichome. Based on the characteristic features, a diagnostic key for identification of the studied species was prepared.

Petal and Sepal Epidermal Micromorphology of Six Lathyrus Taxa (Fabaceae) and their Systematic Value

In this study, the epidermal types and their distribution on dorsal and lateral petals, the trichome types and their density on sepals of Lathyrus chloranthus, L. digitatus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, L. sativus, and L. tuberosus, belonging to sections Lathyrus, Lathyrostylis, Pratensis, and Orobon of the genus Lathyrus in Turkey were investigated using light microscopy (LM) and scanning electron microscopy (SEM), and the systematic significance of these characters was evaluated. These taxa, except L. sativus, are studied for the first time under aspects of the petal and sepal micromorphology. Three major epidermal types were recognized on the petal: tabular rugose striate cells (TRS), areolate cells with more or less striations (AS), and papillose conical striate cells (PCS). TRS and AS were further subdivided into three subtypes. TRS was found on the dorsal and lateral petals of L. chloranthus, L. sativus, and L. tuberosus: the dorsal petals of L. roseus subsp. roseus and the lateral petals of L. laxiflorus subsp. laxiflorus, while AS was present on the dorsal and lateral petals of L. digitatus and the lateral petals of L. roseus subsp. roseus. PCS was found only on the dorsal petals of L. digitatus. Three main types of trichomes on the sepal were observed: peltate glandular, capitate glandular, and nonglandular trichomes. The capitate glandular and nonglandular trichomes were further subdivided into three subtypes. The peltate glandular trichomes were present only in L. chloranthus, but absent in the others. The capitate glandular trichomes were found in L. chloranthus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, and L. tuberosus. The nonglandular trichomes were always present in L. chloranthus and L. laxiflorus subsp. laxiflorus. The present results show that the petal and sepal micromorphology can be used in delimitation of the taxa based on petal and sepal micromorphology.

Leaf micromorphology of Aesculus hippocastanum L. and damage caused by leaf-mining larvae of Cameraria ohridella Deschka and Dimić

The present study is a continuation of our research on the structure of healthy leaves of <em>Aesculus hippocastanum </em>and leaves damaged by larvae of <em>Cameraria ohridella. </em>In this study, the epidermal micromorphology of both leaf surfaces in <em>A. hippocastanum </em>was investigated by scanning electron microscopy (SEM). Light microscopy was used to examine on which side of the leaf blades eggs of <em>Camerari</em><em>a ohridella </em>were laid. The characteristic features of the adaxial and abaxial epidermis were shown. In the hypostomatic leaves of the studied species, the stomata occurred at a density of 173 × mm<sup>-2</sup> and they represented the cyclocytic type. A striated layer of the cuticle was observed only in the adaxial epidermis in which glandular hairs were also present along the midribs. Non-glandular trichomes grew only on the surface of the midribs or in their axils in the abaxial epidermis. We found eggs of <em>C. ohridella </em>only on the adaxial surface of the epidermis. Using SEM, we also observed in the mines leaf tissues damaged by <em>C. ohridella</em>. We found palisade parenchyma to be absent, whereas in the spongy parenchyma there could be seen large intercellular spaces and at places a dense mass of organic matter, formed from damaged cells and larval excrement. The vascular bundles and calcium oxalate crystals remained in the feeding places. We found numerous bacteria, fungal spores and hyphae as well as cleistothecia of Erysiphales in the mines on the surface of the damaged mesophyll.<br /> The glandular trichomes occurring only locally on the leaves, the relatively thin cell walls of the epidermis and a not well-developed cuticle layer on their surface do not protect sufficiently these leaves against the invasion of <em>C. ohridella. </em>On the other hand, damaged tissue areas are a convenient place for the growth of bacteria and fungi.

Petal Development in Lotus japonicus

Previous studies have demonstrated that petal shape and size in legume flowers are determined by two separate mechanisms, dorsoventral (DV) and organ internal (IN) asymmetric mechanisms, respectively. However, little is known about the molecular mechanisms controlling petal development in legumes. To address this question, we investigated petal development along the floral DV axis in Lotus japonicus with respect to cell and developmental biology by comparing wild-type legumes to mutants. Based on morphological markers, the entire course of petal development, from initiation to maturity, was grouped to define 3 phases or 13 stages. In terms of epidermal micromorphology from adaxial surface, mature petals were divided into several distinct domains, and characteristic epidermal cells of each petal differentiated at stage 9, while epidermal cells of all domains were observed until stage 12. TCP and MIXTA-like genes were found to be differentially expressed in various domains of petals at stages 9 and 12. Our results suggest that DV and IN mechanisms interplay at different stages of petal development, and their interaction at the cellular and molecular level guides the elaboration of domains within petals to achieve their ideal shape, and further suggest that TCP genes determine petal identity along the DV axis by regulating MIXTA-like gene expression.

Morphological characteristics, distribution and taxonomic consideration of Chionanthus retusus Lindl. & Paxton in Korea

The morphological characteristics of Chionanthus retusus Lindl. & Paxton in Korea are reviewed in this study through the comparison with its previous records and a distribution map of this species is created using previous flora and voucher specimens. The leaf epidermal micromorphology and the petiole anatomy are also briefly described.

Comparative labellum micromorphology of the sexually deceptive temperate orchid genusOphrys: diverse epidermal cell types and multiple origins of structural colour

Labellum micromorphology was imaged via scanning electron and light microscopy in 32 microspecies and one artificial hybrid of the European terrestrial orchid genus Ophrys, together representing all ten macrospecies circumscribed in the genus via molecular phylogenetics. Imaging of homologous regions of the adaxial surface, paying particular attention to the diagnostic feature of the comparatively reflective speculum, revealed the presence of between three and seven epidermal cell types on each labellum, the less complex labella being plesiomorphic. Epidermal protuberances range from short, domed papillae to long, twisted unicellular filaments. Multiple origins are inferred for pale labellar margins, large yellow appendices (both putative osmophores exuding pseudopheromones), broad flat labella and long lateral horns. Homoplasy in the speculum is manifested in unusually complex or simple outlines and the presence or absence of a pale margin or iridescence. The reflectivity of the speculum is caused by a combination of chemical and physical colour, whereas iridescence can be caused only by physical properties. The specula of most microspecies studied bear striated trichomes, albeit maturing comparatively late in ontogeny and being sufficiently narrow to allow light to reach the flat polygonal trichome bases. Reflectivity appears to be negatively correlated with the convexity and degree of cuticular corrugation shown by these epidermal cells. Two clades (the Speculum + Tenthredinifera + Bombyliflora group and Bertolonii subgroup of the Sphegodes group) have lost specular trichomes and include the most iridescent species; their flat, polygonal, nonstriated cells resemble those observed on the paired pseudoeyes that bracket the stigmas of all Ophrys except the Fusca group. The smooth thick-layered cuticle and dense layers of organelles and starch bodies revealed by preliminary transmission electron microscopy study provide alternative candidates for the primary reflective surface of the speculum; in contrast, the trichomes and conical cells that dominate Ophrys labella, and occur on the specula of all but the most reflective species, absorb and/or diffuse light. Multiple MYB family genes are hypothesized to control epidermal micromorphology. The relative contributions of olfactory, visual and tactile cues to the sophisticated pseudocopulatory pollination mechanism that characterizes Ophrys remain unclear, but the degree of reproductive isolation achieved, and thus the speciation rate, have certainly been greatly exaggerated by most observers.

Evolution of petal epidermal micromorphology in Leguminosae and its use as a marker of petal identity

The legume flower is highly variable in symmetry and differentiation of petal types. Most papilionoid flowers are zygomorphic with three types of petals: one dorsal, two lateral and two ventral petals. Mimosoids have radial flowers with reduced petals while caesalpinioids display a range from strongly zygomorphic to nearly radial symmetry. The aims are to characterize the petal micromorphology relative to flower morphology and evolution within the family and assess its use as a marker of petal identity (whether dorsal, lateral or ventral) as determined by the expression of developmental genes. Petals were analysed using the scanning electron microscope and light microscope. A total of 175 species were studied representing 26 tribes and 89 genera in all three subfamilies of the Leguminosae. The papilionoids have the highest degree of variation of epidermal types along the dorsiventral axis within the flower. In Loteae and genistoids, in particular, it is common for each petal type to have a different major epidermal micromorphology. Papillose conical cells are mainly found on dorsal and lateral petals. Tabular rugose cells are mainly found on lateral petals and tabular flat cells are found only in ventral petals. Caesalpinioids lack strong micromorphological variation along this axis and usually have only a single major epidermal type within a flower, although the type maybe either tabular rugose cells, papillose conical cells or papillose knobby rugose cells, depending on the species. Strong micromorphological variation between different petals in the flower is exclusive to the subfamily Papilionoideae. Both major and minor epidermal types can be used as micromorphological markers of petal identity, at least in papilionoids, and they are important characters of flower evolution in the whole family. The molecular developmental pathway between specific epidermal micromorphology and the expression of petal identity genes has yet to be established.

Studies on leaf epidermal micromorphology, wood element characters and phytochemical screening of three medicinal plants of Convolvulaceae

The scientific evaluation of ethnomedicinally important plants is now being done thoroughly covering various aspects of study like efficacy of the crude drugs, chemistry of active principles, different pharmacognostic parameters, etc. The use of micromorphology and anatomy is now a recognised tool in the field of plant systematics. Therefore, in this investigation the micromorphology of leaf epidermis, stem xylem element characters and phytochemical screening of three ethnomedicinally important members of the family Convolvulaceae namely Evolvulus alsinoides, Evolvulus nummularius and Ipomoea cairica have been studied. The epidermal cells are found to be irregular in shape and the outlines of the cells are wavy in every species. Stomata are amphistomatic and mainly of paracytic type except in Evolvulus nummularius. Trichomes are glandular and non-glandular, unicellular or multicellular, straight or curved. The range of stomatal index varies from 11.40 to 20.00. Palisade ratio ranges from 6.2 to 9.8. The vessel element length ranges from 60.71 um to 357.10 um and the diameter varies from 21.78 um to 66.06 um. Perforation plate is simple and transverse or obliquely placed. Fibres are typical libriform, very long and diameter ranges from 10.71 um to 16.78 um. In every case, tracheids are long with spiral to condensed spiral type of sidewall thickening and diameter is from 07.14 um to 16.07 um. The active compounds are identified by the chemical colour reaction tests belonging to the phytochemical groups of amino acids, alkaloids, reducing sugars, flavonoids, saponins, steroids and triterpenoids, tannins, etc. The findings will be a useful marker for identification of the crude drugs obtained from the selected taxa. The purpose of the study is to know the leaf epidermal micromorphology, wood element characters and phytochemical screening of three ethnomedicinally important plants of the family Convolvulaceae as it has not been properly worked out. These micromorphological features and phytochemical screening will be very helpful in proper identification of respective crude drugs obtained from these three members of Convolvulaceae and also be used in detection of drug adulterants. Thus, it will be a tool in maintaining the quality of the drug obtained from these three plant species.

The Trillium pusillum Michaux Complex (Trilliaceae): Analysis of Pollen and Leaf Epidermal Micromorphology

TIMMERMAN-ERSKINE, M., R. R. DUTE, AND R. S. BOYD (Department of Biological Sciences, Auburn University, AL 36849-5407). The Trillium pusillum Michaux complex (Trilliaceae): Analysis of pollen and leaf epidermal micromorphology. J. Torrey Bot. Soc. 129:175-186. 2002.-The T. pusillum complex consists of five or six southeastern morphogeographical taxa with a confused taxonomic history. Some authors have considered them as a single species, whereas others have split the complex into various combinations of species and varieties. Our study examined pollen and stomatal characteristics of these taxa for their utility as taxonomic characters. All T. pusillum varieties have pollen characterized by somewhat spherical and inaperturate grains with rounded granulate ornamentation. Stomatal complexes lacked subsidiary cells and were aperigenous and homostomatic. Although trends were identified in both pollen diameter and stomatal size and shape, these characters were not reliable variety-specific taxonomic characters. Only T. pusillum var. texanum exhibited both abaxial and adaxial stomata, a feature that consistently distinguished it from other putative varieties that we examined. We suggest that this complex be subdivided into two species, T. texanum Buckley and T. pusillum Michaux, based upon these stomatal distribution patterns.

Chusquea sect. Longiprophyllae (Poaceae: Bambusoideae): A New Andean Section and New Species

Chusquea sect. Longiprophyllae, a group of six species of the Andean montane forests, is described as new based on the vinelike clambering habit, infravaginal branching, abaxially scabrous culm leaves, tightly circular array of subsidiary buds, central bud with an elongated prophyll, dimorphic subsidiary branches, and well developed glume II. Four new species, C. ex- asperata, C. londoniae, C. maculata, and C. longiprophylla, are described, illustrated, and their ranges mapped. Chusquea sneidernii and C. ligulata, two previously described species, are transferred to this section, and are also treated. Two keys to species are provided, one based solely on vegetative characters and the other on vegetative and flowering characters. The foliar epidermal micromor- phology of this section is described and illustrated based on a scanning electron microscopy survey of the six species. Species-specific differences were observed, and the bifurcate or branched papillae on the subsidiary cells of the stomatal apparatus and small papillae on the bulliform cells characterize the section. Chusquea Kunth is a neotropical, primarily montane bamboo genus of at least 120 species (Clark 1989). Its diversity encompasses several evolutionary lines, some of which were re- cently formally recognized as sections (Clark 1989). The sections of Chusquea are defined on the basis of modifications in the morphology of their buds, branches, foliage leaves, and to a lesser extent, inflorescences and spikelets. Re- cent field work in Colombia and Venezuela re- vealed the existence of another well defined group of species with elongated bud prophylls. In this paper, Chusquea sect. Longiprophyllae is formally recognized and described. Four new species and two previously described species comprise the section; all are described and il- lustrated, and their ranges mapped. Evidence is presented to support a monophyletic origin of this section. Because previous studies of foliar epidermal micromorphology demonstrated taxonomically useful patterns of variation within Chusquea (Clark 1986), a scanning electron microscopy (SEM) survey of the foliage leaves of the species of this section was conducted.

SCANNING ELECTRON MICROSCOPY SURVEY OF LEAF EPIDERMIS OF SORGHASTRUM (POACEAE: ANDROPOGONEAE).

Scanning electron micrographs of the foliar epidermes of all 17 species of Sorghastrum are presented. A description of foliar epidermal micromorphology for the genus is followed by short descriptions of the individual species, emphasizing their epidermal differences. Papillar morphology is variable but taxonomically informative in distinguishing among the species of Sorghastrum. Based on the absence or presence of papillae, and differences in papillar morphology, three informal groups within Sorghastrum are recognized: 1) the nonpapillate group including S. balansae, S. rigidifolium, S. setosum, S. contractum, S. minarum, and S. viride; 2) the globose-papillate group including S. elliottii, S. incompletum, S. nudipes, S. nutans, S. scaberrimum, S. secundum, and S. trichopus; and 3) the elongate-papillate group including S. brunneum, S. stipoides, S. chasae, and S. pellitum. No correlation between papillar development and habitat is evident; however, a correlation exists between papillar development and the geographic distribution of the species of Sorghastrum.

A systematic revision of the genus Carex (Cyperaceae) with respect to the section Lupulinae

To assess the phenetic affiliation of species in Carex sect. Lupulinae, we examined achene epidermal micromorphology, using scanning electron microscopy. The newly disclosed differences in achene micromorphology, in particular the presence of silica platforms with or without central bodies, in conjunction with macromorphological features, support the division of section Lupulinae into subsection Lupulinae (comprises Carex lupulina, C. lupuliformis, C. louisianica, and C. gigantea) and subsection Intumescentes (comprises C. intumescens and C. grayi).