Taxonomic significance of alkaloids and iridoid glucosides in the tribe Psychotrieae (Rubiaceae)

Leaves of 15 Brazilian species of Psychotria, three of Rudgea and Palicourea rigida, were analyzed for their alkaloid and iridoid content. Alkaloids were found in three of Rudgea and 14 species of Psychotria, and iridoids were found in Psychotria leiocarpa, which produces asperuloside and deacetylasperuloside. Palicourea rigida yielded no alkaloids but loganin was isolated. The results illustrate the significance of the alkaloids in the chemotaxonomy of some taxa of Psychotrieae. The phytochemical data indicate that the American species of Psychotria with Palicourea could be joined to form the genus Heteropsychotria.     

A revised classification of the sister tribes Palicoureeae and Psychotrieae (Rubiaceae) indicates genus-specific alkaloid accumulation

Phytochemistry Reviews - Tribes Palicoureeae and Psychotrieae (Rubiaceae, Gentianales) are complex and speciose sister groups with a pantropical distribution. Since the initial studies on...     

Pollen of African Spermacoce species (Rubiaceae) Morphology and evolutionary aspects

Pollen morphology of 43 African species of the genus Spermacoce has been investigated by scanning electron and light microscopy. The genus is eurypalynous, which is reflected in the remarkable variation of almost all pollen characters. The average equatorial diameter (E) ranges from 15.8 w m to 115.5 w m. Grains are colporate or pororate. The number of apertures varies from 3 up to more than 25. The majority of species has apertures situated only at the equator (being zonoaperturate), but a few species have pantoaperturate grains. The endoaperture is generally an endocingulum, often with a secondary lolongate or lalongate thinning at the ectocolpus; endocolpi and endopores are also observed. The sexine is usually perforate, but eutectate, foveolate, and (micro)reticulate tecta were also found. Supratectal elements are present as granules, microspines or spines. The inner nexine surface is granular, often with irregular grooves (endocracks). Among native African species, nine pollen types are recognized mainly on the basis of pollen size, aperture morphology and tectum peculiarities. In two of the pantoaperturate types, apertures are in a configuration not yet recorded for the angiosperms in general. Some evolutionary trends are proposed that await verification by further systematic study. Pollen morphological characters have a high taxonomic value in the genus Spermacoce . They provide almost unique identification marks for the species, which enables sharpening of species boundaries. Small groups of related species often share the same pollen type. The genus Borreria , previously separated from Spermacoce on the basis of its fruit morphology only, is not supported by pollen data.     

Morphological variation and its taxonomic and evolutionary significance in the Hawaiian Psychotria (Rubiaceae)

Morphological evidence resulting from a taxonomic revision of the genusPsychotria in the Hawaiian Islands supports previous work which recognized sectionsPelagomapouria andStraussia. The differences between these sections in inflorescence architecture, flower size, anther attachment, and pyrene anatomy, strongly support the contention that at least two introductions to the Hawaiian Archipelago were responsible for the origin of these sections. Whereas the taxa in sectionPelagomapouria are quite distinct from one another morphologically, those in sectionStraussia demonstrate almost continuous morphological intergradation.Straussia taxa also tend to become less distinct when followed from the older to the younger islands of the archipelago. Morphological variation within several complex species is illustrated. The morphological evidence supports the hypothesis thatStraussia has had a shorter tenure in the Hawaiian Islands than hasPelagomapouria and is in a relatively early evolutionary stage of adaptive radiation and speciation.     

Chromosomal behaviour and evolutionary trends in Chlorophytum (Liliaceae)

Chlorophytum laxum R. Rr. (Liliaceae) is a common perennial herb occurring in many parts of India, Ceylon, Borneo, Tropical Africa and Australia. The earlier cytological studies report two numbers of chromosomes, viz. 2n = 14 & 16, for the species. The present study, based on meiotic behaviour, concludes that this species is a segmental allopolyploid from two closely related but still unknown species with 2n = 8 chromosomes. Further evolution proceeded in two different directions. In one, diploidization by chromosomal rearrangements resulted into species with 2n = 16 chromosomes, while in the other, elimination of a non-homologous segment gave rise to species with 2n = 14 chromosomes and several autopolyploids.     

New reports on flavonoids,benzoic- and chlorogenic acids as rare features in the Psychotria alliance (Rubiaceae)

Five flavonoid glycosides, three chlorogenic and one benzoic acid were isolated from leaves of seven species belonging to the genera Notopleura, Palicourea and Psychotria. In most species, common flavonol glycosides based upon quercetin and kaempferol were recorded, which corresponds well to literature data on other species of the Psychotria alliance. From Notopleura polyphlebia, however, the new dihydroflavonol glycoside (2R,3R)-7,4′-O-dimethyl-aromadendrin 5-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (1) was isolated, which is remarkable in terms of both the structure of the aglycone as well as the rarity of apiose as sugar moiety. In addition to flavonoids, benzoic and chlorogenic acids are a common and frequently neglected feature in the alliance, but all appear to be of limited chemosystematic significance when compared to tryptamine-iridoid alkaloids prominently known from this group.     

Novelties in spermacoceae (Rubiaceae) from Bolivia and Paraguay

One new Bolivian species (Borreria pazensis) and three new varieties (Borreria densiflora var.minima, Richardia, scabra var.chacoensis andStaelia virgata var.killeenii) are described and illustrated. The genusDiodella, with three species (D. apiculata comb. nov., D. radula comb. nov., andD. teres), is reported for the first time.Borreria limae, B. wunschmannii, B. scabiosoides var.scabiosoides, andB. scabiosoides var.anderssonii are also reported as new to Bolivia.     

Evolution of breeding systems and fruits in New World Galium and relatives (Rubiaceae)

? Premise of the study: Dioecy occurs in only about 6% of angiosperms, yet it has evolved many times from hermaphroditism. Polygamy is an even more uncommon condition within angiosperms, in which both unisexual and bisexual flowers occur within a species. Polygamy, dioecy, and hermaphroditism all occur within a New World clade of Galium (Rubiaceae), in which dioecy is hypothesized to have evolved from hermaphroditism via polygamy. At least five sections of Galium as traditionally defined by fruit morphology occur within this group. We tested the monophyly of sections defined by fruit morphology and sought to determine origins and pathways of breeding systems within this group. ? Methods: We obtained chloroplast (rpoB-trnC, trnC-psbM, trnL-ndhJ) and nuclear ribosomal (external transcribed spacer) DNA sequences for 89 taxa from the Cruciata-Galium-Valantia (CGV) clade to estimate the phylogeny. Ancestral states for breeding systems, fruit types, and fruit hairs were reconstructed using parsimony and likelihood analyses. ? Key results: We identified nine well-supported lineages of New World Galium taxa. However, none of the sections traditionally defined by fruit morphology are monophyletic. Dioecy is inferred to have arisen at least three times from hermaphroditism; polygamy is inferred to have arisen at least twice from dioecy and at least six times from hermaphroditism. ? Conclusions: Polygamy appears to be a terminal condition in the CGV clade and not a pathway to dioecy. Fruit characters traditionally used in the taxonomy of this group have arisen multiple times within this clade of Galium and are not reliable indicators of shared evolutionary history.     

Two novel Ty1-copia retrotransposons isolated from coffee trees can effectively reveal evolutionary relationships in the Coffea genus (Rubiaceae)

In the study, we developed new markers for phylogenetic relationships and intraspecies differentiation in Coffea. Nana and Divo, two novel Ty1-copia LTR-retrotransposon families, were isolated through C. canephora BAC clone sequencing. Nana- and Divo-based markers were used to test their: (1) ability to resolve recent phylogenetic relationships; (2) efficiency in detecting intra-species differentiation. Sequence-specific amplification polymorphism (SSAP), retrotransposon-microsatellite amplified polymorphism (REMAP) and retrotransposon-based insertion polymorphism (RBIP) approaches were applied to 182 accessions (31 Coffea species and one Psilanthus accession). Nana- and Divo-based markers revealed contrasted transpositional histories. At the BAC clone locus, RBIP results on C. canephora demonstrated that Nana insertion took place prior to C. canephora differentiation, while Divo insertion occurred after differentiation. Combined SSAP and REMAP data showed that Nana could resolve Coffea lineages, while Divo was efficient at a lower taxonomic level. The combined results indicated that the retrotransposon-based markers were useful in highlighting Coffea genetic diversity and the chronological pattern of speciation/differentiation events. Ongoing complete sequencing of the C. canephora genome will soon enable exhaustive identification of LTR-RTN families, as well as more precise in-depth analyses on contributions to genome size variation and Coffea evolution.     

A new combination in palicourea (Rubiceae: Psychotrieae) with ethnobotanical notes from amazonian bolivia

A new combination, Palicourea, Palicourea brachyloba for a white-flowered Amazonian species in anticipation of its use in other publications. Comments on the local name and utilization are given.     

Intraspecific variation and evolutionary trends in Capparis spinosa L. (Capparaceae)

 In order to investigate the variability of the polymorphic Capparis spinosa L., a comparative study was carried out in Sicily on subsp. spinosa and subsp. rupestris. Autecology, phenology, quantitative morphology, plant architecture and leaf development of several populations were examined. These data reveal a parapatric distribution of the two subspecies and support their present taxonomic treatment. Subsp. spinosa is widespread on clay soils and shows remarkable intrapopulational variation. It is characterized by shortened reproductive and vegetative periods, high shoot growth rate, winter-desiccating shoot system and stipular thorns. Subsp. rupestris, less variable and linked with carbonatic and volcanic outcrops, shows prolonged phenological patterns, slow growth rate, woody habit and caducous stipules. A noteworthy phenotypic convergence with subsp. rupestris was observed in individuals of subsp. spinosa growing in rocky habitats. The evolutionary trends of Capparis spinosa in the Mediterranean region are discussed. Received March 29, 2000 Accepted April 6, 2001     

Phylogeny of the Gardenieae (Rubiaceae)

The phylogeny of Gardenieae (Rubiaceae) is evaluated using 70 morphological and anatomical characters and 81 terminal taxa. After successive reweighting of the characters and modified bootstrap tests the following is concluded. The position of the Diplosporinae genera Argocoffeopsis, Calycosiphonia, Cremaspora and Tricalysia with the genera belonging to the tribes Aulacocalyceae, Coffeeae, Octotropideae and Pavetteae, suggests that this subtribe does not belong in Gardenieae. Posoqueria is nested among outgroup genera and consequently is not a member of the tribe. Robbrecht & Puff's informal 'tetrad group' is monophyletic. Likewise, their 'Alibertia group' is supported as monophyletic, although slightly rearranged. On the other hand, their 'Aidia group' must he greatly expanded with several genera in order to be monophyletic, but the monophyly of this group is weakly supported. Several disputed genera should be included in Gardenieae ( Anomanthodia, Amaioua, Brachytome , and supposedly Bertiera ). Most inferred groups, however, exhibit low bootstrap values and should he viewed with caution.     

东亚粗叶木属（茜草科）植物纪要

修订了东亚茜草科粗叶木属植物,新归并１１个种名及２个变种名,建立１个新变种,３个新组合变种和１个新等级亚种。报道２个中国分布新记录种。讨论了一些易于混淆种的界限,以及探讨了一些种的植物地理意义。     

A new species of pagamea (Rubiaceae) from the Brazilian Guayana

Pagamea aracaënsis Boom, endemic to Serra Aracá, Brazil is described and illustrated, and its relationship toP. anisophylla Standley & Steyerm, is discussed.     

Phenylpropanoid glucosides from leaves of Coussarea hydrangeifolia (Rubiaceae)

Phenylpropanoid glycosides, 1'-O-benzyl-alpha-L-rhamnopyranosyl-(1'-->6')-beta-D-glucopyranoside (1) and alpha-L-xylopyranosyl-(4'-->2')-(3-O-beta-D-glucopyranosyl)-1'-O-E-caffeoyl-beta-D-glucopyranoside (2), together with the known derivatives, 1,6-di-O-caffeoyl-beta-D-glucopyranoside (3), 1-O-(E)-caffeoyl-beta-D-glucopyranoside (4) and 1-O-(E)-feruloyl-beta-D-glucopyranoside (5), were isolated from leaves of Coussarea hydrangeifolia. Their structures were determined by IR, HRESIMS, and 1D and 2D NMR experiments, and their antioxidant activities, evaluated by assaying the free radical scavenging capacity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical as substrate. The antioxidant activities of 3 and 4 (IC50 values of 15.0 and 19.2 microM, respectively) were comparable to that of the standard positive control caffeic acid, whilst 2 and 5 were only weakly active and 1 was inactive.