Chemical composition of <Emphasis Type="Italic">Catha edulis</Emphasis> (khat): a review

Khat (Catha edulis) belongs to Celastraceae family which contains 60–70 genera and 850–900 species. It is an indigenous plant to Ethiopia and Yemen as the countries of origin. It is also found in many other east and southern African countries. Khat leaves are chewed by the local people for their stimulant action. The main active ingredient compounds those are responsible for this action is cathinone and a mild stimulant cathine. In addition to these khat contains several phytochemicals such as alkaloids (phenylalkylamines and cathedulins), flavonoids, steroid and triterpenoids, monoterpenes and volatile aromatic compounds, and other miscellaneous compounds like vitamins and amino acids. Hence, this paper presents a comprehensive and unified review of literatures which concerned on the phytochemical composition of khat plant. And it also provides the isolated compounds with their chemical structures.     

The seed appendage of Eriosema (Fabaceae)

A bilobed structure develops from the distal end of the funiculus, primarily by cell enlargement, during the ontogeny of the seed ofEriosema glaziovii Harms. This appendage is present in all species ofEriosema and was found to contain conspicuous oil droplets in the thirteen species examined in this study. The appendage is referred to as a strophiole or a rim-aril although seeds of the genus have been previously described as estrophiolate by other authors.     

MICROPYLAR EXUDATE IN GASTERIA (ALOACEAE) AND ITS POSSIBLE FUNCTION IN POLLEN TUBE GROWTH

The micropylar exudate of Gasteria verrucosa (Mill.) H. Duval was studied using light and electron microscopic techniques. Ovules may contain micropylar exudate before stigma receptivity. During successive phases of stigma receptivity, the number of ovules with micropylar exudate and the amount of micropylar exudate per ovule increases. At the late phase of stigma receptivity, large amounts of micropylar exudate with a smooth to cauliflowerlike appearance were observed. Micropylar exudate is viscous and contains, among other components, proteins and carbohydrates. At all stages of the stigma investigated, ovules situated at the base of the ovary contain a larger quantity of micropylar exudate than those at the top. The appearance of micropylar exudate is related to the degree of development of the embryo sac and it originates primarily from the filiform apparatus. It is assumed that an uptake of water by the ovule initiates the outflow of micropylar exudate from the filiform apparatus into the micropyle. Both ovular pollen tube ingrowth and seed set mark the optimum pollination stage of the stigma, which for both events lies around the onset of stigma receptivity. When pollen tubes have reached the ovary, young micropylar exudate stimulates their growth rate. The presence of micropylar exudate seems to be a requirement for pollen tube penetration, and an interaction between the pollen tube and the micropylar exudate has been proposed. Possibly, the micropylar exudate serves as a nutritional source and, in an optimum condition, as an attractant for approaching pollen tubes.     

Beta-mannosidase (EC 3.2.1.25) activity during and following germination of tomato (Lycopersicon esculentum Mill.) seeds. Purification,cloning and characterization

Beta-mannosidase, a high-salt-soluble enzyme, increases in activity in seeds of tomato prior to the completion of germination. This increase occurs in both the lateral and micropylar endosperm and becomes more evident during post-germinative seedling growth. The beta-mannosidase activity profile is similar to that of endo beta-mannanase although it is the first to increase in the lateral endosperm. Tomato seed beta-mannosidase was purified to homogeneity and its cDNA (LeMside1) obtained by 3'-RACE PCR using oligonucleotide sequences based on four peptide sequences obtained from the purified enzyme. The derived amino acid sequence of the tomato beta-mannosidase shows the enzyme is a member of the Glycosyl Hydrolases Family 1 (GHF1) but has a very low sequence identity with that of beta-mannosidases from non-plant sources; no other plant sequence for the enzyme is known. There appears to be only one gene encoding beta-mannosidase in tomato, the sequence of which has been determined (LeMSide2). Its expression occurs first in the micropylar endosperm, and then declines after germination. This is followed by an increase in its expression in the lateral endosperm, which precedes that of the gene for endo beta-mannanase. Expression of the beta-mannosidase gene increases appreciably in the growing seedling embryo. With this report, the cloning of all three of the enzymes involved in galactomannan mobilization (endo beta-mannanase, alpha-galactosidase and beta-mannosidase) in tomato seeds has now been achieved.     

The development of the fruits and seeds of campomanesia (Myrtaceae)

The glandular nature of the “seed coat” has long been the most important taxonomic character defining the genusCampomanesia. It is shown here that the structure, which has been taken for the “seed coat,” is actually the locular wall. The development of the ovaries and seeds ofCampomanesia is discussed and illustrated. Three characteristics ofCampomanesia are identified as distinguishing it from other genera of the Myrtaceae: (1) the abortion of all but one ovule in each fertile locule; (2) the protective, glandular locular wall that serves as a false seed coat; and (3) the large number of locules in the ovaries. Reasoning is presented to explain the possible sequence of evolutionary origin of these three characteristics.     

Development of the ovule and seed in Costus cuspidatus (N.E.Br.) Maas (Zingiberaceae), with special reference to the formation of the operculum

The ovule primordium of Costus is trizonate and both its integuments are dermally initiated. With other evidence, this strongly suggests that most, if not all, monocotyledons have dermally initiated integuments, indicating a derived status. The mature seed coat of Costus is completely formed by the outer integument and its principal mechanical layer is the endotesta.
The seed of Costus has an aril, an operculum and a micropylar collar. These structures, characteristic of zingiberalean seeds, are each initiated in a different, specific cell layer of the exostome. The aril is completely dermally initiated. The parenchymatic part of the operculum and the micropylar collar are of dual origin, namely dermal at me integumentary region and subdermal at the raphe.     

A preliminary study of the seed anatomy of Zingiberaceae

Seeds in Zingiberaceae comprise an aril, seed coat, perispenn, endosperm, embryo, and micropylar and chalazal region. The seed coat is derived from the outer integument, and can be divided into cxotesta, mcsotesta and endotesta; the mesotesta is further subdivided into hypodcrmis, translucent cell layer and pigmented cell layer. The micropylar region includes a micropylar collar and operculum; in some taxa it also includes a caruncle-like structure or a stalk-like structure. A chalazal pigmented cell group (CPG), endotcstal gap, diaphragm and the course of raphe bundle in the chalazal region may be of systematic significance in some species. There are two types of endotesta in the family: parenchymatous (in tribes Hedychieae, Zingibereae and Globbeae) and sclerenchymatous (in Alpineae). The exception is Pommereschea lacknen , which is placed in Alpineae but has the parenchymatous type of endotesta. For this and other reasons this taxon should be transferred to another tribe. On the basis of seed characters, Hedychieae, Zingibereae and Globbeae are apparently closely related, although Hedychieae and Zingibereae differ from Globbeae which has a multiple-layered exotestal epidermis. Seeds of most Zingibereae have a peculiar carunclelike structure at the base of the seed which forms the expanding part beyond the micropylar collar. Zingiberaceae and Costaceae are connected through tribe Alpineae with a sclerenchymatous type of endotesta.     

Seed formation in two species of Adesmia (Fabaceae): co‐occurrence of micropylar and lateral endosperm haustoria in legumes and its taxonomic value

Seed ontogeny of Adesmia bicolor and Adesmia latifolia was analysed using light microscopy and standard histological techniques. Fertilization was porogamic. Linear proembryonal tetrads were observed in A. bicolor. The robust elongated suspensors possessed specialized basal cells. The nucellar epidermis became endothelial. The free‐nuclear endosperm produced a micropylar, filamentous and ephemeral haustorium and a lateral sac‐like haustorium at the funicular side. The cellular endosperm was initiated from the micropylar zone after the cordiform embryo stage. It mostly disintegrated in mature seeds. The sclerified bilayered testa was derived from the outer ovular integument. Different astrosclereid arrangements beyond the lens in both Adesmia species may be related to the different habitats of the two species. The occurrence of both micropylar and lateral nuclear endosperm haustoria has so far not been reported in Fabaceae and is the most distinctive embryological character of Adesmieae. The taxonomic value of the mostly uniform morphology of the suspensor in the Adesmia species studied could also be relevant. The nature of seed endothelia in many Fabaceae requires accurate redetermination prior to taxonomic use. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 602–612.     

Testa and seed appendage morphology in Aeschynanthus (Gesneriaceae): phytogeographical patterns and taxonomic implications

The current sectional classification of the genus Aeschynanthus Jack, essentially based on seed morphology, presents some problems of species placement. A comparative SEM survey of seed and seed appendages was undertaken in order to assess the value of this classification. Seeds of 99 taxa (that is about two‐thirds of the estimated total) were examined and found to fall into two types, A and B. Type A has spiral testa cell orientation, papillae formed from a single cell and short smooth appendages. Type B is recognized by the straight orientation of the testa cells, combined with the presence of papillae formed from the raised ends of two adjacent cells on the long hair‐like appendages and usually on the testa. Only six of the investigated species did not fall into either category. Three have straight testa cell orientation combined with single‐cell papillae and short smooth appendages; the papillae and appendage characters place them in type A. Three have spiral testa cell orientation and short smooth appendages but the testa cells have slightly raised ends; these are also placed in Type A. The three subtypes in Type A are equivalent to the sections Haplotrichium s.s., Microtrichium and Aeschynanthus, but the divisions are less clear than those within Type B. However, other morphological characters support sectional separation. Type B subdivides into three: two subtypes equivalent to sections Polytrichium and Diplotrichium, and a third encompassing section Xanthanthos together with part of the current sect. Haplotrichium, and here referred to as sect. X. There is sufficient morphological correlation with seed type to make the sectional position of many species clear without recourse to seed, particularly in sects Polytrichium, Diplotrichium, Haplotrichium S.S. and Aeschynanthus. There is strong correlation between seed type and geographical distribution. Sects. Microtrichium and Aeschynanthus, with Type A seed, are essentially Malesian. Groups with Type B seed are largely confined to mainland south and south‐east Asia, except for sect. Polytrichium which is more widespread, possibly due to the greater effectiveness of a coma of hairs in wind dispersal. It is suggested that Type A seed, probably sect. Microtrichium, is the least determined and Type B sect. Polytrichium the most derived seed type. Based on these findings a revised key to the sections is provided.     

Parasegmental appendage allocation in annelids and arthropods and the homology of parapodia and arthropodia

The new animal phylogeny disrupts the traditional taxon Articulata (uniting arthropods and annelids) and thus calls into question the homology of the body segments and appendages in the two groups. Recent work in the annelid Platynereis dumerilii has shown that although the set of genes involved in body segmentation is similar in the two groups, the body units of annelids correspond to arthropod parasegments not segments. This challenges traditional ideas about the homology of "segmental" organs in annelids and arthropods, including their appendages. Here I use the expression of engrailed, wingless and Distal-less in the arthropod Artemia franciscana to identify the parasegment boundary and the appendage primordia. I show that the early body organization including the appendage primordia is parasegmental and thus identical to the annelid organization and by deriving the different adult appendages from a common ground plan I suggest that annelid and arthropod appendages are homologous structures despite their different positions in the adult animals. This also has implications for the new animal phylogeny, because it suggests that Urprotostomia was not only parasegmented but also had parasegmental appendages similar to extant annelids, and that limb-less forms in the Protostomia are derived from limb-bearing forms.     

Ovule morphology, embryogenesis and seed development in three Hylocereus species (Cactaceae)

Pre-embryonic and embryonic stages and seed developments were studied in the diploids Hylocereus monacanthus and Hylocereus undatus and the tetraploid Hylocereus megalanthus. Ovule morphology was similar among species except for micropyle entrance. H. monacanthus had the thickest and most robust suspensor. Embryo developmental time, measured from fertilization to maturity, was significantly more prolonged in H. megalanthus. Typical to Cactaceae, the seed coat was formed by one layer of sclerenchymatous cells, but was more lignified in H. megalanthus. Morphological features common to all species included (1) cellular type endosperm with independent patterns of development in the chalazal and micropylar zones, forming a haustorium layer from the chalazal zone to the embryo; (2) an endothelial layer surrounding the embryo sac almost complete; (3) a nucellar summit growing into the micropyle; and (4) a placental obturator and a funicle connecting the ovarian tissue to the ovule. Seed development was typically endospermic (exendospermic orthodox seeds). Anomalies included two egg cells in the same embryo sac, two embryos developing in the same ovule, and embryos developing from the chalazal pole region. Total seed number and seed viability were significantly lower in H. megalanthus than in the other two taxa. Embryos at different developmental stages were observed in aborted H. megalanthus seeds.     

Seed coat morphology and its systematic significance in Juncus L. (Juncaceae) in Egypt

The seed morphology of nine taxa of Juncus from Egypt has been investigated using light and scanning electron microscopy, to determine the importance of seed coat features as taxonomic characters. Macro- and micromorphological characters, including seed shape, color, size, seed appendages, epidermal cell shape, anticlinal boundaries, and outer periclinal cell wall and secondary cell wall sculpture are presented. Four types of seed appendages are recognized: (i) seeds with two appendages; (ii) seeds without appendages; (iii) seeds with minutely a piculate at one end; and (iv) seeds with minutely a piculate at both ends. Two types of anticlinal cell wall boundaries,(i) raised-channeled, straight and (ii) raised, straight or sinuous, and three different shapes of outer periclinal cell wall are described: (i) flat; (ii) concave; and (iii) flat to slightly concave. The secondary sculpture of the cell wall varies from striate to microreticulate or reticulate, and smooth to finely folded. Seed characters provide useful data for formulating the taxonomy of Juncus both on the subgeneric and sectional level. A key for the identification of the investigated taxa based on seed characters is provided.     

Lectin binding to the egg envelopes in Eyprepocnemis plorans (Charp.) (Orthoptera, Acrididae)

The distribution of glycoconjugates in the egg envelopes of Eyprepocnemis plorans was investigated using various FITC-conjugated lectins. In the epichorion, the lectins ConA, SBA and WGA each have particular binding patterns, while TPA binding is confined to its deepest regions only. The glycoconjugates of the micropylar wall present different characteristics from those of the surrounding chorion. The vitelline coat shows a marked binding for WGA and TPA only; below the inner micropylar openings, this binding pattern is uniform over the whole extent of the coat and therefore it is not possible to identify specific binding sites for these two lectins. Contrary to what has been observed in some other insect species, the vitelline coat does not seem to be involved in the structural organization of the mycropyles.     

A new species of Blakea (Melastomataceae) from Panama with foliaceous sepal appendages and zygomorphic flowers

The new species Blakea bocatorena is described from Bocas del Toro province in Panama. It is only the third species to be described in the genus that has foliaceous appendages on the sepals. The other two species with these sepal appendages are B. calycosa and B. tuberculata. Blakea bocatorena differs from the latter two species in that it has white petals and a type of herkogamy in which the style is opposite the stamens and results in a zygomorphic flower. In B. calycosa and B. tuberculata, the larger petals are pink-magenta and tuberculate with the stamens encircling the exserted style resulting in a radially symmetric herkogamous flower.     

Development of endosperm inScrophularia himalensis with a discussion on the variation in the endosperm of the tribeScrophularieae (Scrophulariaceae)

Scrophularia himalensis has anab initio cellular endosperm. A transverse division separates a micropylar chamber from a chalazal chamber. The second division is vertical in both, the third is also vertical but at right angles to the second and restricted to the micropylar chamber just as the fourth transverse division. The four-celled micropylar haustorium is branched, highly aggressive, and persists for a long time during seed development. The bicelled chalazal haustorium is non-aggressive and is relatively short-lived. The endosperm proper is ruminate. Variation in the early ontogeny of the endosperm and the structure of endosperm haustoria in the tribeScrophularieae are evaluated.     

Molecular Phylogeny of the Small Ermine Moth Genus Yponomeuta (Lepidoptera,Yponomeutidae) in the Palaearctic

Background

The small ermine moth genus Yponomeuta (Lepidoptera, Yponomeutidae) contains 76 species that are specialist feeders on hosts from Celastraceae, Rosaceae, Salicaceae, and several other plant families. The genus is a model for studies in the evolution of phytophagous insects and their host-plant associations. Here, we reconstruct the phylogeny to provide a solid framework for these studies, and to obtain insight into the history of host-plant use and the biogeography of the genus.

Methodology/Principal Findings

DNA sequences from an internal transcribed spacer region (ITS-1) and from the 16S rDNA (16S) and cytochrome oxidase (COII) mitochondrial genes were collected from 20–23 (depending on gene) species and two outgroup taxa to reconstruct the phylogeny of the Palaearctic members of this genus. Sequences were analysed using three different phylogenetic methods (parsimony, likelihood, and Bayesian inference).

Conclusions/Significance

Roughly the same patterns are retrieved irrespective of the method used, and they are similar among the three genes. Monophyly is well supported for a clade consisting of the Japanese (but not the Dutch) population of Yponomeuta sedellus and Y. yanagawanus, a Y. kanaiellus–polystictus clade, and a Rosaceae-feeding, western Palaearctic clade (Y. cagnagellus–irrorellus clade). Within these clades, relationships are less well supported, and the patterns between the different gene trees are not so similar. The position of the remaining taxa is also variable among the gene trees and rather weakly supported. The phylogenetic information was used to elucidate patterns of biogeography and resource use. In the Palaearctic, the genus most likely originated in the Far East, feeding on Celastraceae, dispersing to the West concomitant with a shift to Rosaceae and further to Salicaceae. The association of Y. cagnagellus with Euonymus europaeus (Celastraceae), however, is a reversal. The only oligophagous species, Y. padellus, belongs to the derived western Palaearctic clade, evidence that specialisation is reversible.     

EMBRYOLOGICAL DEVELOPMENT OF LACHNANTHES CAROLINIANA (HAEMODORACEAE)

Embryological development of Lachnanthes caroliniana was studied utilizing standard anatomical techniques and SEM. Lachnanthes has a monocotyledonous anther wall development (endothecial cells with spiral secondary wall thickenings), successive microsporogenesis, and amoeboid (periplasmodial) tapetal development. Mature pollen grains are 2-nucleate with a proximal, fusiform generative cell. Ovules are initiated as 5–7 cylindrical primordia from a common placental base. Basal ovular swellings collectively contribute to the enlarged, peltate placenta. Mature ovules are pleurotropous, anatropous, bitegmic, and crassinucellate; the nucellus consists of a chalazal hypostase, radially elongate lateral cells, and a prominent micropylar nucellar cap. Megasporogenesis is successive, forming a linear tetrad of megaspores. Megagametogenesis is monosporic; the female gametophyte is of the Polygonum-type with relatively large, pyriform antipodals. Endosperm formation is helobial, resulting in the establishment of a ring of four thick-walled basal endosperm cells (the chalazal chamber) and numerous free nuclei (in the micropylar chamber). The mature cellular endosperm is filled with starch grains and has a chalazal cavity and a thick-walled peripheral layer. The discoid, peltately attached seeds have marginal wings derived by anticlinal divisions and buckling of the outer integument alone. Inner and middle cuticular layers are present in the seed coat. Lachnanthes is similar to all other investigated members of the Haemodoraceae in major embryological features. The significance of embryological evidence with regard to interfamilial classification is discussed. Future studies of ovule and seed development may prove valuable in phylogenetic studies in assessing the homology of placental, ovule, and seed morphology and anatomy.