Crassulacean acid metabolism (CAM) in an epiphytic ant-plant, Myrmecodia beccarii Hook.f. (Rubiaceae)

This study demonstrates unequivocally the presence of crassulacean acid metabolism (CAM) in a species of the Rubiaceae, the fourth largest angiosperm plant family. The tropical Australian endemic epiphytic ant-plant, Myrmecodia beccarii Hook.f., exhibits net CO₂ uptake in the dark and a concomitant accumulation of titratable acidity in plants in the field and in cultivation. Plants growing near Cardwell, in a north Queensland coastal seasonally dry forest of Melaleuca viridiflora Sol. ex Gaertn., accumulated ~50 % of their 24 h carbon gain in the dark during the warm wet season. During the transition from the wet season to the dry season, 24 h carbon gain was reduced whilst the proportion of carbon accumulated during the dark increased. By mid dry season many plants exhibited zero net carbon uptake over 24 h, but CO₂ uptake in the dark was observed in some plants following localised rainfall. In a shade-house experiment, droughted plants in which CO₂ uptake in the light was absent and dark CO₂ uptake was reduced, were able to return to relatively high rates of CO₂ uptake in the light and dark within 12 h of rewatering.     

Review of the genus perama (Rubiaceae)

The nomenclatural and taxonomic history of the genusPerama Aubl. (Rubiaceae) is discussed. The major trends of evolution within the genus are characterized, and the sections of the genus are delimited. A new section,Diperama Kirkb. & Steyerm., is described. The distribution of the genus is updated, and centers of species concentration are indicated. A complete synonymy is given for the genus, and the type species cited. An artificial key to the species is given ; a new combination,P. parviflora (Standl.) Kirkb. & Steyerm., is mads; and three new species are described,P. harleyi Kirkb. & Steyerm.,P. irwiniana Kirkb. & Steyerm., andP. sparsiflora Standl. ex Steyerm. & Kirkb.     

Leaf flavonoids ofGalium sect.Aparinoides (Rubiaceae)

13 taxa belonging to 4 “species groups” ofGalium L. sect.Aparinoides (Jord.)Gren. produce 15 leaf flavonoids: Apigenin-7-diglucoside, Luteolin-7-monoglucoside and 7-diglucoside, Diosmetin, Diosmetin-7-monoglucoside and 7-diglucoside; Kaempferol-3-rutinoside, Kaempferol-3,7-diglucoside, Quercetin, two Quercetin-3-monoglycosides, Rutin, Quercetin-3-rutinoside-7-glucoside, Quercetin-7-glycoside and an unidentified aglycone. TheG. trifidum, G. obtusum andG. palustre groups (with the exception of theG. tinctorium subspecies andG. elongatum) have similar flavone-flavonole patterns, while theG. antarcticum group produces a specific pattern. Leaf flavonoids of theG. trifidum andG. antarcticum group are inhomogenous, becauseG. tinctorium subsp.tinctorium andG. antarcticum lack flavones. For all taxa (with the exception of those of theG. antarcticum group) intraspecific variation is demonstrated, and 4 populations ofG. trifidum subsp.trifidum, G. tinctorium subsp.tinctorium,G. obtusum subsp.obtusum andG. labradoricum even exhibit intrapopulation variation. The implications of flavonoid data on the systematics and the astonishing intrapopulation and intraspecific variation are discussed.     

Leaf Nodule Development in Psychotria kirkii Hiern. (Rubiaceae)

The initiation, development and structure of the leaf nodulesof the Rubiaceous shrub Psychotria kirkii Hiern. has been studiedin detail at the ultrastructural level. Bacteria, maintainedin the shoot tip in the secretions from dendroid colleters,invade the substomatal chamber of stomatal pores which formprecociously on the abaxial leaf surface. Proliferation of theepidermis around the pore pushes the bacterial cavity deep intothe lamina, thus forming a small internal nodule. Endophyte-mediatedschizogeny of the cells surroundng the nodule causes it to expandwhile at the same time giving rise to an interconnected reticulumof invasive host cells which are involved in metabolite exchangebetween microoganisms and host plant. Bacterial morphology changesafter entry of the microsymbiont into the host plant and, bythe time the nodule is mature, the bacteria exhibit distinctpleomorphism. Senescent nodules are shown to accumulate lipidand starch. The developmental process is discussed in the lightof existing information on this symbiosis. Psychotria kirkii, leaf nodule development, symbiosis, ultrastructure     

Screening for leaf-associated endophytes in the genus Psychotria (Rubiaceae)

Burkholderia endophytes were identified within the leaves of non-nodulated members of the genus Psychotria. In contrast to leaf-nodulated Psychotria species, which are known to accommodate their endosymbionts into specialized endosymbiont-housing structures, non-nodulated species lack bacterial leaf nodules and harbor endosymbionts intercellularly between mesophyll cells. Based on molecular data (rps16, trnG, and trnLF), the phylogenetic reconstruction of the host plants revealed a separate origin of leaf-nodulated and non-nodulated Psychotria species. Despite a distinct phylogenetic position of the two host clades, the endophytes of the non-nodulated plants were not placed into a single monophyletic group but were found to be closely related to the leaf-nodulated endosymbionts. The observation of genetically similar endophytes in both nodulated and non-nodulated Psychotria lineages suggests that the host plant is playing a crucial role in the induction of leaf nodule formation. Moreover, the concentration of endosymbionts into specialized leaf nodules may be considered as a more derived evolutionary adaptation of the host plant, serving as an interface structure to facilitate metabolic exchange between plant and endosymbiont.     

Photodynamic activity of anthraquinones isolated from Heterophyllaea pustulata Hook f. (Rubiaceae) on MCF-7c3 breast cancer cells

Searching for agents that could be effective in the treatment of cancer, special highlight has focused on the study of numerous plant-derived compounds. We previously demonstrated that anthraquinones (AQs) isolated from a vegetal species: Heterophyllaea pustulata Hook f. (Rubiaceae), such as rubiadin, rubiadin-1-methyl ether, soranjidiol, soranjidiol-1-methyl ether exhibit photosensitizing properties without antecedents as photodynamic agents in malignant cells. In the present study, we investigated the potential role of these AQs as a phototoxic agent against human breast carcinoma using MCF-7c3 cells. All AQs exhibited significant photocytotoxicity on cancer cells at the concentration of 100 μM with 1 J/cm² light dose, resulting soranjidiol-1-methyl ether in complete cell destruction. The observed cellular killing by photoactivated AQs exhibited close relation with singlet oxygen production, except for soranjidiol-1-methyl ether, where cell viability decrease is in relation to uptake by tumor cells.     

Phylogenetic systematics of the monotypic genus Hayataella (Rubiaceae) endemic to Taiwan

Hayataella (Rubiaceae) is a monotypic genus endemic to Taiwan that comprises H. michelloides. In recent years, Hayataella was considered to be synonymous with Ophiorrhiza; however, no specific data have been reported, and the systematic treatment of Hayataella has been unclear. To elucidate the systematic treatment of Hayataella, molecular phylogenetic analyses based on ITS of nrDNA, atpB–rbcL, and trnK/matK of cpDNA were conducted with four Ophiorrhiza species. In the Bayesian and the most parsimonious trees, H. michelloides was included in the Ophiorrhiza clade. The monotypic status of Hayataella is, therefore, not considered appropriate, and the combination Ophiorrhiza michelloides (Masam.) H. S. Lo is supported.     

非洲山毛豆叶片蛋白组双向电泳样品制备方法的建立

以非洲山毛豆叶片为材料,对非洲山毛豆总蛋白质3种提取方法(TCA/丙酮沉淀法、尿素/硫脲法和酚-甲醇/醋酸铵沉淀法)以及3种蛋白裂解液进行比较分析。结果表明,采用酚-甲醇/醋酸铵沉淀法提取非洲山毛豆叶片总蛋白,用蛋白裂解液(7mol/L尿素,2mol/L硫脲,4%CHAPS,40mmol/LTris-base,1%Bio-LytepH3.5-10,65mmol/LDTT)裂解蛋白1h,2-DE图谱分离到的蛋白点效果最好。此方法适合于色素、多酚及黄酮类次生代谢物含量较多的非洲山毛豆叶片总蛋白制备方法。     

Agouticarpa, a new neotropical genus of Tribe Gardenieae (Rubiaceae)

Agouticarpa, a new genus of the informalAlibertia group (Rubiaceae), is described and illustrated. It comprises six species, and occurs from Costa Rica to Bolivia. Three species are here described as new:Agouticarpa grandistipula, A. hirsuta, andA. velutina. Additionally, three new combinations are made:A. curvifolia andA. williamsii (previously inGenipa) andA. isernii (previously inAlibertia). Agouticarpa is characterized by being dioecious, having elliptic to abovate, membranaceous stipules, male flowers in a branched dichasial or thyrse-like inflorescence, a poorly developed cup-shaped calyx, pollen grains with 3–7 apertures, and large globose fruits.     

Development and Structure of Bacterial Leaf Nodules in Psychotria bacteriophila Val. (Rubiaceae)

The development and mature structure of bacterial leaf nodules in Psychotria bacteriophila were studied by using light and electron microscopy. Bacteria in mucilage surrounding the shoot apex pass through certain stomates in leaf primordia into the substomatal chamber. These chambers enlarge and become nodules as the yound leaves grow out of the apical region. Surrounding mesophyll cells grow into each nodule and form a cellular reticulum whose interstices are occupied by bacteria. Each intrusive mesophyll cell wall is unusually thick and continually supplemented by vesicles originating from dictyosomes. The gram-negative bacteria are often surrounded by capsules. Nodule bacteria contain several crystal-like dense bodies. A population of normal, dividing, and degenerating bacteria is found in each nodule. Extensive membranes occur between the bacteria. A hypothesis is proposed to explain certain aspects of this obligate symbiotic relationship.     

樟科柔毛润楠正确名称的考订

在确认润楠属（Machilus Nees）应作为一独立属后,根据《国际植物命名法规》,恢复柔毛润楠的正确名称应为Machilus villosa（Roxb．）Hook．f．     

Notes on African species of the genus Anisopappus Hook. & Arn. (Asteraceae)

Two new species of the genus Anisopappus Hook. & Arn. (Asteraceae) are described A. athanasioides Paiva & Ortiz, from Angola, and A. pseudopinnatifidus Ortiz & Paiva, from Namibia. The morphological variability of the A. chinensia-A. africanus complex is studied and two new combinations are proposed: A. chinensis subsp. africanus (Hook. fil.) Ortiz & Paiva and A. chinensis subsp. lobatus (Wild) Ortiz & Paiva.     

Notes on African species of the genus Anisopappus Hook. & Arn. (Asteraceae)

Two new species of the genus Anisopappus Hook. & Arn. (Asteraceae) are described: A. athanasioides Paiva & Ortiz, from Angola, and A. pseudopinnaididus Ortiz & Paiva, from Namibia. The morphological variability of the A. chinensis-A. africanus complex is studied and two new combinations are proposed: A. chinensis subsp. africanus (Hook, fil.) Ortiz & Paiva and A. chinensis subsp. lobatus (Wild) Ortiz & Paiva.     

On the identity of Guatteria costata Hook. f. & Thomson (Annonaceae)

Examination of the type from Burma of Guatteria costata in the East India Company herbarium at Kew shows that it belongs in Trivalvaria and provides an earlier name for T. dubia (Kurz) J. Sinclair. A new combination is proposed. A further synonym, Polyalthia montana Ridl., is lectotypified.     

Cytotaxonomic investigations on some species of the genus Galium (Rubiaceae) from the Balkans

The results of a cytological and morphological investigation on the following species of the genus Galium L. collected in the Balkans are described and discussed: Sect. Platygalium Koch: G. rotundifolium L. and G. boreale L.; Sect. Aparinoides (Jord.) Gren.: G. palustre L.; Sect. Leiogalium Ledeb.: G. heldreichii Hal., G. lovcense Ur., G. album Mill. with the ssp. album, pycnotrichum (H.Br.) Krendl and prusense (C. Koch) Ehrend. et Krendl, G. lucidum All., G. corrudifolium Vill., G. scabrifolium (Boiss.) Hausskn., G. procurrens Ehrend., G. schultesii Vest, and G. bulgaricum Velen.; Sect. Kolgyda Dumort.: G. aparine L., G. intricatum Margot et Reut., G. parisiense L., G. divaricatum Pourr. ex Lam. and G. tenuissimum Bieb.     

Evidence for Cytokinin in Bacterial Leaf Nodules of Psychotria punctata (Rubiaceae)

Cytokinin activity based on two bioassays was at least 100-fold higher in Psychotria punctata leaf discs with bacterial nodules than in discs without them. Nodulated discs from young leaves yielded 0.4 to 6 μg of cytokinin (zeatin equivalents) per g fresh weight of leaf tissue, whereas non-nodulated discs from the same leaves yielded 0 to 0.003 μg per g fresh weight. These estimates probably include free-base cytokinins and, if present, any nucleoside cytokinins precipitable by acidic silver nitrate. Cytokinin concentrations in Psychotria leaf nodules appear to be higher than normally found in green leaves of other plants. In l-butanol-acetic acid-water (12:3:5, v/v), the one peak of activity chromatographed with an R_F similar to zeatin's, but both number and identity of the active substance(s) remain unknown. These findings suggest that a cytokinin is produced by bacteria in leaf nodules of P. punctata and that it is involved in the symbiosis.     

Neomussaenda (Rubiaceae), a new genus from Borneo

A new genus, Neomussaenda is described to accommodate the species Greenea xanthophytoides and the new species Neomussaenda kostermansiana , described here. Neomussaenda is endemic to Borneo and differs from the genus Greenea in the induplicate-valvate aestivation, shape and indumentum of the corolla, heterostyly, bifid stipules, pollen morphology, seed exotestal cells with tuberculate inner wall, ideoblasts filled with numerous minute druses, and fruits not opening while attached to the inflorescence, but may open later loculicidally by decay. It is close to the genera Pseudonmussaenda and Schizomussaenda , with which it shares the induplicate-valvate aestivation and fruits with a splitting zone for loculicidaly dehiscence. Neomussaenda is placed in the tribe Isertieae.