Volker Bittrich

Phylogeny of Clusiaceae Based on rbcL sequences

Phylogenetic models of the Clusiaceae have so far been based on morphological data only. As an additional source of phylogenetic information, the chloroplast gene rbcL was sequenced for 26 species, representing all available genera of Clusiaceae. The DNA data were analyzed cladistically together with previously published sequences. The results show that the aquatic family Podostemaceae is nested inside Clusiaceae as the sister group of subfamily Hypericoideae or tribe Hypericeae. The subfamilies Kielmeyeroideae and Clusioideae, as delimited in recent morphology‐based classifications, are largely supported as monophyletic. The sole exception is Clusiella, which links with Kielmeyeroideae rather than with Clusioideae. We conclude that pollination by resin‐collecting bees arose independently in Clusiella and the Clusioideae: Clusieae.

Phylogeny of the clusioid clade (Malpighiales): Evidence from the plastid and mitochondrial genomes

PREMISE OF THE STUDYnThe clusioid clade includes five families (i.e., Bonnetiaceae, Calophyllaceae, Clusiaceae s.s., Hypericaceae, and Podostemaceae) represented by 94 genera and ≈1900 species. Species in this clade form a conspicuous element of tropical forests worldwide and are important in horticulture, timber production, and pharmacology. We conducted a taxon-rich multigene phylogenetic analysis of the clusioids to clarify phylogenetic relationships in this clade.nnnMETHODSnWe analyzed plastid (matK, ndhF, and rbcL) and mitochondrial (matR) nucleotide sequence data using parsimony, maximum likelihood, and Bayesian inference. Our combined data set included 194 species representing all major clusioid subclades, plus numerous species spanning the taxonomic, morphological, and biogeographic breadth of the clusioid clade.nnnKEY RESULTSnOur results indicate that Tovomita (Clusiaceae s.s.), Harungana and Hypericum (Hypericaceae), and Ledermanniella s.s. and Zeylanidium (Podostemaceae) are not monophyletic. In addition, we place four genera that have not been included in any previous molecular study: Ceratolacis, Diamantina, and Griffithella (Podostemaceae), and Santomasia (Hypericaceae). Finally, our results indicate that Lianthus, Santomasia, Thornea, and Triadenum can be safely merged into Hypericum (Hypericaceae).nnnCONCLUSIONSnWe present the first well-resolved, taxon-rich phylogeny of the clusioid clade. Taxon sampling and resolution within the clade are greatly improved compared to previous studies and provide a strong basis for improving the classification of the group. In addition, our phylogeny will form the foundation for our future work investigating the biogeography of tropical angiosperms that exhibit Gondwanan distributions.

Polyisoprenylated benzophenones from Clusia floral resins.

From the floral resins of various Clusia species, seven polyisoprenylated benzophenones were isolated. HPLC allowed their quantification in all resins, revealing a distribution of benzophenone derivatives distinct from each other. In some species the staminal oils were collected and oleic, stearic and palmitic acids were the main constituents.

Floral resins of clusia spp.: Chemical composition and biological function

Abstract The floral resins of five species of Clusia belonging to two taxonomic sections of the genus were investigated. These resins are used by pollinating bees for nest construction. The major components of these reins are polyisoprenylated benzophenones, a class of biologically active compounds. We found clusianone and three hitherto unknown compounds, grandone, nemorosone and hydroxy-nemorosone.

The ecological and taxonomic importance of flower volatiles of Clusia species (Guttiferae).

The chemical composition of floral volatiles of sixteen species of Clusia (Guttiferae) belonging to four different taxonomic sections of the genus was investigated. The volatiles were extracted from fresh petals by microhydrodistillation and analysed by GC/MS. The composition of the volatiles was in part, but not always, related to the taxonomic position of the species, and to a minor extent to the type of pollinator observed on the flowers as revealed by clustering analysis. The composition of the volatile components of female and male flowers belonging to the same species (C. grandiflora, C. lanceolata, C. paralicola, C. parviflora and C. spiritu-sanctensis) was found to be almost identical. Field bioassays showed the petal extracts to be attractive to pollinating bees.

Two polyisoprenylated benzophenones from the floral resins of three Clusia species

Abstract From the floral resins of Clusia nemorosa male, C. nemorosa hermaphrodite, Clusia rosea female, Clusia grandiflora male, C. grandiflora female, Clusia insignis male (all section Chlamydoclusia ). C. renggerioides male (with pistillodium), C. renggerioides male (without pistillodium), C. renggerioides female (all section Cordylandra ) belonging to the family Clusiaceae, we have isolated two novel polyisoprenylated benzophenones, nemorosone II and 6- epi -nemorosone, and a xanthone. The latter is the first member of this class of compounds ever isolated from the genus Clusia . HPLC allowed the quantification of these and other methylated benzophenones in the methylated resins revealing that indeed these are the major constituents of Clusia floral resins. Oleic, stearic and some unusual long chain esters and acids are the main constituents of the stamen oils.

Pollination biology ofSymphonia globulifera (Clusiaceae)

The pollination biology ofSymphonia globulifera was studied in Central Amazonia, Brazil. As suggested by the bird syndrome of the flowers, these are mainly pollinated by hummingbirds. Occasional visits by other birds, butterflies and more rarely bees, as well as tamarin monkeys were also observed.Trigona bees partly destroy the flower tube to rob nectar. The possibility thatS. globulifera may not be primarily adapted to hummingbird pollination is discussed. The pollen is intermixed in an oily fluid secreted by the anthers (antheroil). Each of the five stigmas consists of a pore-like opening at the apex and a small chamber behind it. The antheroil mixed with pollen is absorbed by capillarity into the chamber when deposited on the pore. the pollen germinates inside the stigma. The presence of antheroil and pore-like stigmas in the flowers of the closely relatedPlatonia insignis indicate a similar mode of pollination. The results of this study are compared with observations in some otherClusiaceae (Caraipa, Clusia, Garcinia, Mahurea), where floral oils or floral resin occur. The role of these substances in the pollination process and their relation to the evolution of flower biology inClusiaceae are briefly discussed.

Flower Morphology and Pollination Biology of Some Clusia Species from the Gran Sabana (Venezuela)

The flower morphology and its relation to the pollination biology of four species of Clusia (Guttiferae) from the Gran Sabana (Guyana highland) belonging to three sections of the genus is described. The flowers of both genders of C. schomburgkiana (sect. Polythecandra) and of C. columnaris (sect. Omphalanthera) offer resin as a reward for small bees acting as pollinators. In both species the androecial morphology is highly derived. Functionally, this can be interpreted in terms of minimization of contact of the sticky resin and the pollen. Male flowers of C. pusilla and Clusia sp. of sect. Clusiastrum offer pollen as a reward for large, middle-sized and small bees, who vibrate the anthers to collect pollen. Female flowers are rewardless and unusual in the genus by the presence of long styles. The pollinating bees are probably deceived by the combination of papillose stigmas and the yellowish staminodes directly below these. The bees pollinate the stigmas when trying to vibrate them. The evolution of the flower biology in the genus Clusia is briefly discussed.

FLORAL BIOLOGY OF SOME CLUSIA SPECIES FROM CENTRAL AMAZONIA

The floral biology of 3 species of Clusia sect. Chlamydoclusia and 3 species of Clusia sect. Cordylandra from Central Amazonia was investigated. The flowers of both sexes offer resin as the reward for pollinating bees. The male flowers of the species of sect. Chlamydoclusia may additionally offer pollen. Principal pollinators observed were bees, mainly of the tribes Euglossini and Trigonini. In the male flowers of sect. Chlamydoclusia the pollen is kept separately from the floral resin, but in sect. Cordylandra it is mixed with the resin. The elongated connectives of the fertile stamens in sect. Chlamydoclusia secrete droplets of an oily fluid which probably serves as accessory pollenkitt. The stigmas of the pistils and pistillodes of flowers of sect. Cordylandra secrete an oily fluid; possible functions of this are discussed. C. renggerioides has male plants with two different floral morphs; pollen of both produced fertile seeds when used to pollinate female plants. The taxonomic significance of the different pollination strategies in Clusia and their evolution is discussed.

The chemistry of flower rewards -- Oncidium (Orchidaceae)

Most of the flower-pollinator interactions are based on rewards as pollen and nectar. Our group however, has been focusing on the chemical composition of unusual rewards like floral resins and floral oils. We are now reporting the chemistry of the floraloils of Oncidium pubes which are composed of diacylglycerols and triacylglycerols possessing one or two acetyl residues and one long chain fatty acid. The substitution pattern of some of the diacylglycerols was inferred to be 1, 3 based on spectroscopic analyses and comparison with 3 different synthetic compounds obtained from D-mannitol, oleic acid and acetic acid. The fatty acid residues possess double bond and/or acetoxy group as functional groups. Finally our results provided chemical evidences that pollination of Oncidium pubes is not based upon an attraction-deception system but on floral lipids and this is the first time this has ever been mentioned in the literature.